Dissertations/Thesis

Clique aqui para acessar os arquivos diretamente da Biblioteca Digital de Teses e Dissertações da UFRN

2024
Dissertations
1
  • ARIVONALDO BEZERRA DA SILVA
  • BIBLIOMETRIC ANALYSIS AND MACHINE LEARNING TO DETERMINE OPTIMIZED MANGANESE- BASED OXYGEN CARRIERS FOR APPLICATION IN CHEMICAL LOOPING PROCESSES

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • SIBELE BERENICE CASTELLA PERGHER
  • RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS
  • DENER DA SILVA ALBUQUERQUE
  • REBECCA ARAÚJO BARROS DO NASCIMENTO SANTIAGO
  • Data: Jan 30, 2024


  • Show Abstract
  • The scope of this dissertation consists of determining optimized manganese-based oxygen carriers for application in Chemical Looping processes using Bibliometric Analysis and Machine Learning. The Bibliometric Analysis carried out in this study offers a comprehensive view of statistical data and trends related to manganese-based oxygen carriers for applications in Chemical Looping (CL) processes from 2006 to 2023. The search was carried out in the Web database of Science resulted in a total of 426 documents, of which 65 were carefully selected using the ProKnow-C method to compose the study portfolio. Then, to carry out the bibliometric analysis (construction of tables, graphs and bibliometric maps) the Web of Science platform, VOSviewer and Excel were used. Soon after, an Excel spreadsheet was created containing the input and output data referring to the articles in the bibliographic portfolio for application in Machine Learning, to determine the optimized oxygen carriers based on manganese. Then, the oxygen carriers were experimentally reproduced and XRF, DRX, SEM and oxygen transport capacity (Roc) analyzes were carried out on a thermobalance. Bibliometric analysis revealed the considerable potential of manganese-based synthetic oxygen carriers for application in Chemical Looping processes. According to analyzes of the most relevant articles, these materials have been shown to have reduced friction rates and a low tendency to agglomerate in continuous fluidized bed reactors. Furthermore, the analysis will contribute to the optimization of the physicochemical properties of oxygen carriers, as it considered the influence of the type of active phase and support on reactivity tests, oxygen transport capacity, friction rate and agglomeration in continuous fluidized bed reactors in CL processes. Regarding data processing in Machine Learning, it was found that the data relating to Oxygen Transport Capacity adjusted very well to the Random Forest and XGBoost regression models, with highly accurate predictions with a high coefficient of determination for the training set. (R2 = 0.9511 in Random Forest and R2 = 0.9999 in XGBoost) and test (R2 = 0.9352 in Random Forest and R2 = 0.9309 in XGBoost), low mean squared errors (MSE = 0.0728 in Random Forest and MSE = 0.0776 in XGBoost) and Root Mean Square Error for the test set (RMSE = 0.2698 in Random Forest and RMSE = 0.2786 in XGBoost). Furthermore, analyzing the graphs of the input variables versus Roc for the training sets of the two models, it is possible to determine two oxygen carriers that have good oxygen transport capacity and good mechanical resistance: TO_MnFe (76% Mn and 24 % Fe) and TO_MnMg (60% Mn and 40% Mg).

2
  • RITA DE CÁSSIA DANTAS DA SILVA
  • Optimization of the synthesis of silica nanoparticles obtained from diatomite for application in modified drug delivery systems.

  • Advisor : NEDJA SUELY FERNANDES
  • COMMITTEE MEMBERS :
  • NEDJA SUELY FERNANDES
  • RAQUEL DE MELO BARBOSA
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Mar 14, 2024


  • Show Abstract
  • Modified drug delivery systems (MDDSs) are valuable allies in the quest for optimizing pharmaceuticals, whether to modulate their release profiles or increase their bioavailability. In this context, silica particles in the nanometric size range stand out as excellent materials for MDDS applications, thanks to their favorable interactions with drugs provided by silanol groups. Experimental planning is a widely applied tool in various scientific fields, and in this study, its relevance is emphasized in the synthesis of silica nanoparticles as promising drug delivery systems. The research details the synthesis process of silica nanoparticles from diatomite using the sol-gel method, along with meticulous material characterization through analytical techniques such as X-ray diffraction (DRX), X-ray fluorescence (FRX), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (MEV), nitrogen adsorption/desorption (N2), dynamic light scattering (DLS), and zeta potential. Following the successful optimization of the synthesis, particles within the range of 292.5 ± 33.0 nm were obtained, with a yield of 90% and a polydispersity index of 0.218 ± 0.041. The experimental planning enabled the attainment of particles with appropriate size, high yield efficiency, and low polydispersity. The unique characteristics of sílica particles, especially their favorable interactions with drugs due to silanol groups, point to notable potential in modulating drug release profiles and increasing their bioavailability. The incorporation of these modified release systems represents a significant advancement in the field of therapeutics, allowing for more effective and personalized approaches in the treatment of various diseases and medical conditions.

3
  • MARIANA RAQUEL DE LIMA SILVA
  • Study of the adsorption of synthetic dyes methylene blue and Congo red and the antibiotic tetracycline using the clay mineral halloysite

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • LUCIENE DA SILVA SANTOS
  • JOSE LUIS CARDOZO FONSECA
  • CARLOS AUGUSTO CABRAL KRAMER
  • ENRIQUE RODRÍGUEZ CASTELLÓN
  • LEILA MARIA AGUILERA CAMPOS
  • Data: Mar 22, 2024


  • Show Abstract
  • Halloysite (Hal) is a clay mineral with the possibility of application in various areas of industry, mainly due to its tubular morphology. The use of this material as an adsorbent in the process of removing medications, such as tetracycline, and for removing synthetic dyes, such as congo red (CR) and methylene blue (MB) in an aqueous medium, is considered a efficient, non-toxic method of low cost. The use of Hal to rebate dyes proved to be economically and environmentally viable for industrial application. In this work, the characterization of this material, in its natural form (HAL) after acid treatment (HAL-A), was carried out using the techniques of X-ray fluorescence (XRF), X-ray diffraction (XRD), microscopy scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray excited photoelectron spectroscopy (XPS), and N2 adsorption/desorption. TEM analyzes showed the formation of nanotubes measuring 60 to 600 nm in length and the adsorption/desorption of N2 indicated that the clay mineral is mesoporous with a surface area of 38.10 m2.g-1 for HAL-A. Several kinetic and equilibrium models were applied to obtain the adsorption mechanism. Fitting the experimental data to the pseudo-second order (R2 >) kinetic model indicated that the mechanism for this process is based on chemisorption for both adsorbates. The maximum tetracycline adsorption capacity calculated from the Langmuir equilibrium isotherm (R2 = 0.9909) was 4.08 mg.g-1 for HAL-A. The removal capacity of the study drug reached 92% with HAL and 98% with HAL-A. The adsorbent also showed the potential to remove CR (> 98%) and MB (> 85%) in 180 min, using 0.3 g of adsorbent and an initial dye concentration of 250 mg.L-1. The clay mineral halloysite showed high efficiency as an adsorbent material for the removal of both dyes and the drug tetracycline, standing out for being a natural, low-cost and environmentally friendly material.

4
  • PEDRO ÍTALO DA CRUZ
  • CHITOSAN-BASED SUPERPARAMAGNETIC COMPOSITE FOR TETRACYCLINE ADSORPTION

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • JOSE LUIS CARDOZO FONSECA
  • LETICIA STRECK
  • Data: May 13, 2024


  • Show Abstract
  • Polymer-based magnetic compounds have desirable properties for use in environmental remediation, such as high surface area and easy removal. Both chitosan and magnetite are biocompatible, biodegradable and non-toxic, in addition to being low-cost and easy to operate, which allows their use in wastewater treatment. Therefore, this study was carried out to obtain the chitosan-based magnetite compound (CS/Fe3O4) through the coprecipitation method, where the tetracycline adsorption capacity of the compound was investigated and the equilibrium time was identified. The adsorption studies were prolonged at temperatures of 15, 25 and 35 ± 2 °C and were monitored by readings on the UV-Vis spectrophotometer at 357 nm. The compound was characterized by infrared, X-ray diffraction, zeta potential and magnetic measurements, which confirmed that the deposit had been obtained. The results showed that the adsorption of tetracycline at 25 ºC reached the Lagmuir and Sips models, while the adsorption at 35 ºC reached the Freundlich and Sips models. The compound showed a tetracycline adsorption capacity of 12.5 ± 0.15 mg/g.

5
  • JOSÉ RODRIGUES DE MORAIS FILHO
  • Sorption of basic blue dye 41 (BB41) in a particulate system commercial chitosan

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • JOSE LUIS CARDOZO FONSECA
  • DAVI SERRADELLA VIEIRA
  • ZILVAM MELO DOS SANTOS
  • Data: May 28, 2024


  • Show Abstract
  • The Sorption of the dye basic blue 41 was carried out on a system particulate of commercial chitosan in aqueous solution. Dye adsorption isotherms were carried out at 15°C, 25°C, 35°C and 45°C, where an increase in adsorption was observed with increasing temperature, indicating a possible endothermic behavior. At 15°C about 50% of the dye was removed at the lowest concentration of the isotherm, followed by 60% at 25°C, 70% at 35°C and 92% at 45°C, all at the lowest concentration worked. The calibration curve was performed using a non-linear regression method, where 𝑅 2 = 0,9998, showing good correlation. The theoretical adsorption model that presented the best correlation was the Sips model, that is, at low concentrations of dye the model reduces to the Freundlich model and at high concentrations it reduces to the Langmuir model. All data was handled in Python.

6
  • PEDRO FELYPE FERREIRA ARAÚJO
  • Synthesis and application of silver nanoparticles (AgNPs) for quantification of scale inhibitors and scale cations in the petroleum industry.

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • MARCOS ANTONIO VILLETTI
  • MIGUEL ANGELO FONSECA DE SOUZA
  • RAFAEL DA SILVA FERNANDES
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Jun 5, 2024


  • Show Abstract
  • The search for alternative analytical methods for determining scale inhibitors and scale cations has aroused interest in the petroleum industry. In this sense, silver nanoparticles (AgNPs), more specifically the optical properties of Localized Surface Plasmon Resonance (LSPR), become a promising material for the development of nanoplatforms for spectral optimization and nanosensors. optics. Thus, the objective of this work was to combine AgNPs with Raman spectroscopy (SERS), UV-Vis spectroscopy and digital images (using a smartphone and free software, Image J) to determine the concentration of scale inhibitors (ATMP and DTPMP) and fouling cations (Mg+2, Ca+2, Sr+2 and Ba+2). These methodologies were based, respectively, on the properties of AgNPs for Raman signal amplification, variation in the absorbance intensity of the plasmonic band (400 nm) and changes in the color of the silver nanoparticle solution in the presence of the analyte. The SERS effect allowed the detection of ATMP in concentrations in the order of 10-4 M. Furthermore, digital imaging and UV-Vis spectroscopy analyzes quantified fouling cations and the inhibitor DTPMP in concentrations in the order of 10-6 M, with excellent linear regression. Characterizations by UV-Vis spectroscopy and Dynamic Light Scattering (DLS) proved that the sensor is based on the mechanism of aggregation or stabilization of AgNPs, depending on the analyte with which they interact. Thus, the results obtained demonstrated that the methodologies developed are efficient, reliable, low-cost and less laborious, when compared to traditionally used methodologies (volumetry and ICP-OES).

7
  • FRANCISCO EMANUEL DA SILVA
  • Nanostructured mesoporous materials with different morphologies: Support for co2 conversion catalyst

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • Gabriel Orlando Ferrero
  • ANNE GABRIELLA DIAS SANTOS
  • ANTONIO SOUZA DE ARAUJO
  • MARIELE IARA SOARES DE MELLO
  • MELISSA GURGEL ADEODATO VIEIRA
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Jun 10, 2024


  • Show Abstract
  • Carbon dioxide has been the subject of many global discussions due to its great impact on the planet's impact on the planet, among many sources of emissions is the oil and energy industry. There are many alternatives on how to reduce this problem, for example, hydrogenation to produce methanol. This is a profitable process, which has attracted many studies, such as the use of silica supports for anchoring copper, zinc and zirconium-based catalysts. Among these supports there are nano-structured mesoporous materials such as SBA-15 and KIT-6, which due to their textural properties, among others, have attracted a lot of attention in this process. These properties can be improved through the change in morphology, which occurs through its synthetic process. Thus, the objective of this work is to synthesize nanostructured mesoporous materials of the SBA-15 type in different morphologies and KIT-6, in order to obtain different textural properties, to be used in the hydrogenation of carbon dioxide (CO2) to obtain Methanol, using hydrothermal synthesis at different reaction temperatures. The materials were characterized using x-ray diffraction, N2 adsorption and desorption, Scanning Electron Microscopy (SEM) and Furrier transform infrared (FTIR). Materials in different morphologies were successfully obtained, with different textural properties, such as specific area, external area, porous volume, pore diameter and wall thickness and their influence on the material structure, such as mesoporous parameter and chemical groups. existing on the surface of the material. CO2 adsorptions were carried out to evaluate the adsorption capacity of each material. The reactions were carried out for conversion to obtain methanol and each product was identified using gas chromatography.

Thesis
1
  • CRISLÂNIA CARLA OLIVEIRA MORAIS
  • Electrochemical technologies: Characterization of a flow recirculation reactor, degradation and detection of Norfloxacin.

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • ELISAMA VIEIRA DOS SANTOS
  • JOSÉ EUDES LIMA SANTOS
  • POLLYANA SOUZA CASTRO
  • SUELY SOUZA LEAL DE CASTRO
  • Data: Jan 31, 2024


  • Show Abstract
  • Water contamination and pollution are priority and emerging issues, both from a scientific and technological point of view. The need to develop efficient methodologies for treating and monitoring water and effluents has grown significantly. In this context, electrochemical technology (ET) has stood out both in the development of sensors and in the application of electrochemical advanced oxidative processes (EAOP). In this work, ET was used to characterize a flow recirculation reactor with parallel rectangular plates of Ti/TiO2RuO2IrO2 (anode) and Ti (cathode), and for the degradation and detection of the drug Norfloxacin (NOR). The diffusion limit current technique was used to determine the experimental mass transfer coefficient (km) and the dimensionless numbers at different flow rates (25, 75, 250 and 500 L h 1), and computational fluid dynamics (CFD) to evaluate the flow velocity distribution within the reactor. The km values and the CFD simulation showed a system totally dependent on the flow rate and the correlation of the dimensionless numbers indicated the predominance of a turbulent regime, at any flow rate. The optimal condition for using the proposed reactor was at a flow rate of 500 L h 1 (km = 1.9 × 10 4 m s 1) and its efficiency was confirmed by electrochemical oxidation studies of 2.5 × 10−4 mol L−1  NOR, at different current densities (j). The degradation process was monitored by UV-visible spectroscopy and total organic carbon (TOC). Molecular absorption spectrophotometry showed a decrease of 70%, 92% and 85% of the initial drug concentration, and TOC analysis showed a mineralization of 28%, 42% and 36% for 20, 40 and 60 mA cm  2, respectively. The drug degradation process was confirmed by ion chromatography (IC), which indicated the formation of short-chain organic acids (formic and acetic acids) at the end of electrolysis. The biodegradability index was also investigated and the results (BOD5/COD ≥ 0.5) showed that after electrochemical treatment the substrate was transformed into a more biodegradable material, which favors the mitigation of environmental impacts. Sequentially, an amperometric sensor with a simple approach was developed, using a carbon fiber (CF) rod as a transducer to monitor online the degradation process of the NOR molecule via EAOP. The electroactivity study of NOR on CF using Britton-Robinson buffer at pH 2.0 showed an irreversible oxidation peak at 1.13 V vs. Ag/AgCl. By correlating Ep versus pH, it was possible to indicate the pKa values of the drug (6.5 and 8.1); the pH study indicated that the determining step of the reaction involved 1 proton and 1 electron in an EC mechanism; and the potential scan rate study showed a mixed adsorption-diffusion process. For the amperometric analysis, the potential was set at 1.2 V, which presented the highest current value. The calibration curve presented a linear range between 1.6 µmol L 1 and 30.0 µmol L 1, with R2 = 0.998, and detection (DL) and quantification (QL) limits of 0.01 µmol L 1 and 0.4 µmol L 1, respectively. The reproducibility and repeatability presented a DPR of 2.1% and 2.9%, respectively, indicating the accuracy of the chronoamperometric sensor. The applicability of the proposed sensor was compared to that of the spectrophotometric method by monitoring the NOR degradation process by EAOP and the results obtained were in agreement. In this way, electrochemical technology can be effectively applied from different perspectives, both in monitoring and mitigating environmental pollutants.

2
  • IZAIAS CAMPOS DA PAIXÃO
  • Electrorefinery of high-value-added carboxylic acids and green hydrogen through electrochemical oxidation of lignina.

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • JOÃO MILLER DE MELO HENRIQUE
  • JUSSARA CÂMARA CARDOZO
  • Data: Feb 7, 2024


  • Show Abstract
  • A growing concern for issues related to environmental impacts has intensified the search for technologies in effluent remediation, renewable energies, and sustainable sources of chemical precursors. Electrochemical oxidation for promoting the reforming of organic effluents can be an alternative for obtaining high-value industrial chemical reagents. The main challenges are associated with the high energy cost of oxidative remediation processes, which can be minimized with renewable energy sources such as wind and photovoltaic. In this research, a reactor with a divided flow by an anionic ion exchange membrane was used, separating the anodic and cathodic compartments. As anodic electrodes, the following were used: Nb/BDD (Niobium/Boron-Doped Diamond) and DSA® (Ti/TiO2, RuO2, and IrO2), with a Ni-Fe mesh (Nickel-Iron) as the cathode, were used for remediating synthetic lignin effluents (a residue from the production process). The oxidative cleavage of lignin resulted in the generation of carboxylic acids in the anodic compartment and green hydrogen in the cathodic compartment. Using a BDD electrode, the best results were achieved with the following concentrations under experimental conditions of 0.5 mol L-1 NaOH and J=100 mAcm-2: oxalic acid 86.03 mg L-1, acetic acid 15.67 mg L-1, formic acid 8.64 mg L-1, and vanillic acid 0.6795 mg L-1. With a DSA electrode, the best results were obtained under similar experimental conditions: oxalic acid 53.14 mg L-1, formic acid 10.58 mg L-1, acetic acid 2.11 mg L-1, and salicylic acid 0.011 mg L-1. The best results for green hydrogen production were 2.59 L in experiments with a BDD anode under experimental conditions of 1 mol L-1 NaOH and J=100 mAcm-2, and 2.93 L in experiments with a DSA anode under experimental conditions of 0.5 mol L-1 NaOH and J=100 mAcm-2. In this context, the results obtained indicate that promoting electro-refining in lignin-based effluents is a viable alternative for obtaining value-added products, such as carboxylic acids widely used in the industry, and green hydrogen.

3
  • LUIS OTAVIO DE ARAUJO
  • PRODUCTION OF COMPOSITE FILMS BASED ON GELATIN, BENTONITE AND SULFANILAMIDE FOR APPLICATION AS WOUND DRESSING.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • FABIO GARCIA PENHA
  • IANE MAIARA SOARES DE SOUZA
  • RONALDO DOS SANTOS FALCÃO FILHO
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Mar 25, 2024


  • Show Abstract
  • There has been much discussion about the treatment and social and economic damage of wounds. This topic has become increasingly relevant due to antibiotic-resistant bacteria. In this sense, one of the approaches to treating infected wounds is the use of antimicrobial composite materials. Based on this, the objective was to develop composite films based on Gelatin, Bentonite, and Sulfanilamide with antimicrobial activity for wound dressings. The starting materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-ray fluorescence (XRF). The  composite films  were characterized for water absorption capacity, moisture content, solubility, and in vitro antimicrobial capacity. For the analysis of the results, the ANOVA statistical test was applied, considering p < 0.1. The results of the tests for moisture, water absorption capacity, and solubility were significant at the probability level, with some films absorbing more than 200% in 60 minutes. Through simultaneous optimization using Box-Behnken design, an ideal formulation containing 14.88% Gelatin (w/v), 15% glycerol (v/v), and 2.5% Bentonite (w/w) was obtained. The insertion of Sulfanilamide into the Bentonite structure was carried out by cation exchange at different pHs, and its entry was confirmed by XRD and TGA, where it was attested that the pH (pH = 4 and pH = 7) did not interfere with the amount of adsorbed antibiotic, remaining around 5%. Composite films containing antibiotics were effective against Staphylococcus aureus and Escherichia coli microorganisms, qualifying them as promising wound dressings.

4
  • ALYXANDRA CARLA DE MEDEIROS BATISTA
  • THERMOCATALYTIC PYROLYSIS OF MICROALGAE BIOMASS USING PURE KIT-6 IMPREGNATED WITH COBALT AND MOLYBDENUM

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • CARLOS ALBERTO MARTINEZ HUITLE
  • ALBERTO WISNIEWSKI JUNIOR
  • EDJANE FABIULA BURITI DA SILVA
  • FABÍOLA CORREIA DE CARVALHO
  • Data: Apr 23, 2024


  • Show Abstract
  • A renewable and promising alternative to mitigate greenhouse gas emissions in the environment is the use of microalgae biomass. Therefore, the work aims to evaluate pre-treatment processes applied to microalgae, then synthesize KIT-6 and impregnate it with Cobalt and Molybdenum and, finally, evaluate the influence of these materials on the thermocatalytic pyrolysis of microalgae. The kinetic study was carried out using the Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods to evaluate the degradation of microalgal biomass. The thermodynamic parameters: Enthalpy (ΔH), Gibbs free energy (ΔG) and entropy (ΔS) were also calculated and, finally, the analysis of the bio-oils obtained from thermocatalytic pyrolysis was carried out. The pyrolysis of Monoraphidium sp. confirmed that the second acetylation promoted greater bio-oil formation, reaching a yield of 40%. Based on the correlation coefficient (R2) values, the KAS kinetic model best suits the degradation process, presenting Ea values of 147.30; 138.60; 145.80; 144.88 and 166.43 kJ.mol-1 for the following samples MA II, K6MA II, CoK6MA II, MoK6MA II and CoMoK6MA II, respectively. The average values of ΔH, ΔG and ΔS indicate that the thermal and thermocatalytic conversion of microalgae biomass is characterized as an endothermic, non-spontaneous and low reactivity process. Thermocatalytic pyrolysis showed a decrease in nitrogen compounds, indicating that KIT-6 pure and with the addition of metals improved the quality of the bio-oil.

5
  • RAFAEL BARBALHO DE LIMA
  • Formation of mesopores in zeolitic material of MWW topology by alkaline treatment

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • ANTONIO SOUZA DE ARAUJO
  • ADONAY RODRIGUES LOIOLA
  • IANE MAIARA SOARES DE SOUZA
  • LINDIANE BIESEKI
  • VINÍCIUS PATRÍCIO DA SILVA CALDEIRA
  • Data: Apr 26, 2024


  • Show Abstract
  • Due to their unique characteristics, zeolites have a wide range of applications. However, the presence of a uniquely microprose structure restricts its use in reactions involving bulky molecules. Therefore, to solve the problem of accessibility of bulky molecules to the active sites of zeolites, the focus has been on the development of zeolites with hierarchical structures. Hierarchical zeolites present a combination of microporosity, characteristic of zeolites, with an additional level of porosity that can be in the range of mesopores or macropores, allowing greater accessibility. Given the methods developed to obtain hierarchical zeolites (Top-down and Bottom-up), alkaline treatment, one of the processes that constitutes the Top-down method, has been widely used due to its simplicity and efficiency. Alkaline treatment through the desilication process promotes the formation of secondary porosity by removing silicon atoms from the zeolitic structure. In alkaline treatment, several factors can influence the formation of secondary porosity, such as Si/Al ratio, morphology, structure, pore-directing agents, among others. In this work, alkaline treatment was carried out on MCM-22 zeolite with a Si/Al ratio equal to 15 and 50, with a two-dimensional and three-dimensional structure, obtained in rotational and static form, and with different types and quantities of pore-directing agents (CTAB and TPAOH). All synthesized materials presented crystalline phases referring to the MWW zeolite structure. The synthesis in the rotational form presented a rounded and thin platelet cluster morphology, while the static form presented more homogeneous and thick rounded platelets. All samples subjected to alkaline treatment showed lower crystallinity than the starting sample, due to partial destruction of the structure, caused by the removal of silicon atoms, however samples with two-dimensional structures showed greater crystallinity when compared to three-dimensional structures.

6
  • EDLA FREIRE DE MELO
  • Catalytic cracking of Pachira aquatica Aubl. oil: PY-GC/MS study using HZSM-5.

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • RENATA MENDONÇA ARAUJO
  • RENATA MARTINS BRAGA
  • ADRIANO LINCOLN ALBUQUERQUE MATTOS
  • JOSÉ LUIZ FRANCISCO ALVES
  • Data: May 31, 2024


  • Show Abstract
  • Biofuels play a crucial role in the transition to a more sustainable and environmentally friendly energy matrix. The oil obtained from the seeds of the fruit of Pachira aquatica Aubl. (PAA), also known as Munguba, stands out as a promising source of raw material to produce biofuels and chemical compounds of industrial interest, through thermochemical conversion processes. Its composition has significant amounts of saturated fatty acids, especially palmitic acid (C16:0), along with the unsaturated fatty acids oleic (C18:1) and linoleic (C18:2). The objective of this study is to characterize the seeds and oil from PAA with a focus on evaluating their energy potential to produce 2G drop-in advanced biofuels and valuable products for the chemical industry. The seeds were collected, and after cleaning and characterization, the oil was extracted by mechanical pressing. Among the seed characterizations, the ash content (4.05%), moisture (3.09%), volatile components (91.79%) were consistent with previous studies carried out on seeds of the same species. From the extracted oil, a satisfactory yield of 36.0% was observed, in addition to notable thermal stability, withstanding temperatures of up to 250 °C and presenting a high calorific value (37.94 MJ/kcal). Comprehensive physicochemical analyses, including ash, density, viscosity and determination of acidity, iodine, saponification, peroxides, and refraction indices were carried out. A preliminary study using conventional analytical pyrolysis of the oil revealed a predominance in the formation of aliphatic hydrocarbons in the C7-C18 range, with a low number of oxygenated compounds. In catalytic pyrolysis using zeolite type HZSM-5, a significant reduction in oxygenated compounds was observed, with the predominance of aliphatic hydrocarbons in the ranges of C4-C13 at 500 °C and of C7-C14 at 300 °C, with characteristic of drop-in aviation fuels. From these data, a 32 factorial design was carried out in conjunction with the principal component analysis (PCA) and response surface (RSM) methodology to investigate the effect of the independent temperature variables of the catalytic windmill (300, 400 and 500 ° C) and the biomass/catalyst ratio (2, 6 and 12 mg of catalyst) in the response variables, such as hydrocarbon content by the number of carbons in the chains and compound content by range of biofuels. The best condition was shown to be with the lowest temperature (300 °C) and smallest amount of catalyst (2 mg) showing better distribution of products in the gaps of gasoline (46.5%), diesel (91.2%), kerosene (56.8%) and lubricating oil (54.8%). In all variations of catalytic bed temperatures there was no formation of oxygenated products and a high yield of aromatic compounds, including benzene, toluene, ethylbenzene, and xylene (BTEX), which are products of great industrial interest. The use of the HZSM-5 catalyst provided an improvement in the products formed, due to its ability to promote decarbonization, decarbonylation, deoxygenation and aromatization of structures, due to its acidic properties and porous structure. These results point to the significant potential for application of PAA seed oil in obtaining advanced drop-in biofuels and selectivity in aromatic bioproducts for the chemical industry.

7
  • THUANNY MOURA DE SOUSA
  • Ruthenium Nitrosyl Complexes: Synthesis, Characterization, Reactivity and action towards plasmid DNA

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANIEL DE LIMA PONTES
  • DULCE MARIA DE ARAUJO MELO
  • FRANCISCO ADILSON MATOS SALES
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • SÉRGIO XAVIER BARBOSA ARAÚJO
  • Data: Jul 19, 2024


  • Show Abstract
  • Nitric oxide (NO) is a signaling molecule involved in several biological processes, including the regulation of blood pressure, neurotransmission, immunological responses, antibacterial activity and anticancer activity. For this reason, nitrosyl complexes have been investigated as NO donors in order to improve the biological applications of this molecule that depends on modulating the structure of the complexes to interact or act on potential molecular targets. In this context, this paper aims to develop new ruthenium nitrosyl complexes of the system [Ru(bpy)(L)(NO2)(NO)](PF6)2, where L are the ligands phen = 1,10'- phenanthroline, phendione = 1,10'-phenanthroline-5,6-dione and bpy = 2,2'-bipyridine, capable of acting as nitric oxide releasers in biological systems. The compounds were obtained from the cis-[Ru(bpy)(L)Cl2] precursor complexes in water and ethanol, with the addition of the ligand sodium nitrite in HTFA 4 mol.L -1 . Trough the infrared technique, in KBr pellets, the complexes exhibited vibrational modes at 1941 and 1944 cm1 associated with NO+ with phenanthroline and phendione, respectively, indicating the coordination of the nitric oxide ligand. Using the UV-vis technique, in acetonitrile, it was possible to identify intraligand bands of π → π* character in the ultraviolet region as well as charges transfer transitions from ruthenium to polypyridine ligands around 450 nm. The cyclic voltammograms obtained in 0.1 mol.L-1 NaTFA and pH = 3.5 showed a half-wave potential of 122 mV for the complex with phenanthroline and 133 mV with phendione, both referring to the NO+/0 redox couple. Regarding UV-Vis reactivity, the complexes showed evidence of NO release in the presence of glutathione and cysteine due to the generation of intermediate products at 450 and 380 nm as well as the formation of the aqueous complex at 450 nm. Meanwhile, in square wave voltammetry, the reaction of the compounds with glutathione, histidine and methionine showed qualitative signs of NO release, due to the appearance of processes in the range of 100-150 and 500-700 mV characteristic of the redox pairs NO+/0 and Ru3+/2+, respectively. Finally, (pBR322) plasmid DNA cleavage tests revealed that in the dark the complexes do not exhibit activity even with up to 60 µM of the compounds. However, under blue LED irradiation (460 nm) and in the presence of glutathione, the complexes showed signs of cleavage, therefore altering their form I (supercoiled) structure between forms II (open circular) and forms III (linear form).

8
  • ADRIANA PERPETUA FIGUEIREDO PAULISTA
  • Synthesis of carbon nanotubes from the catalytic conversion of ethylbenzene over SrFe12O19/SiO2 oxide: Application in the photocatalytic degradation of the industrial dye Remazol Red

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • GERALDO EDUARDO DA LUZ JUNIOR
  • MARCO ANTONIO MORALES TORRES
  • NEFTALÍ LENIN VILLARREAL CARREÑO
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: Jul 23, 2024


  • Show Abstract
  • Carbon-based materials have stood out due to their variety of applications such as photocatalysis. Thus, strontium hexaferrite dispersed in silica was prepared by the Pechini method and used as a catalyst in the ethylbenzene reaction to produce carbon filaments and subsequent application in the photodegradation of the remazol red dye. The presence of SrFe12O19, Fe2O3 and amorphous silica phases was confirmed according to XRD, Raman and XPS analysis. The SEM and TEM results of the oxides indicate cluster and sponge-like morphology. It was possible to observe the formation of carbon filaments by SEM analysis after the CCVD method that arose during the catalytic ethylbenzene reaction. TEM images confirm the generation of carbon nanotubes (~67 nm). The XRD after reaction shows the formation of graphite carbon, SrFe12O19, amorphous SiO2, and Fe0 phases, confirming the hematite reduction. The growth of nanotubes occurs from metallic iron, considering that the tip of the tube contains only iron, according to EDS results. The Raman spectrum exhibited the characteristic D and G bands of carbon, where the ID/IG ratio decreased with increasing temperature, indicating an increase in carbon encapsulation with increasing temperature. The reaction with the best catalytic performance achieved an average ethylbenzene conversion of 99% was more selective to ethene (~ 93%) at 650°C. Furthermore, it was possible to carry out a simple theoretical-computational study regarding the distribution of the sites in a 2D plane by constructing maps and proposing a mechanism for the carbon nanotubes formation from the ethylbenzene conversion. Finally, the obtained materials were applied in the remazol red dye degradation, achieving complete degradation in 15 min for the material synthesized at 650°C. Materials reduced in hydrogen at different temperatures were also applied in the same reaction to verify the influence of carbon, showing that carbon favors the photodegradation of the dye.

2023
Dissertations
1
  • LUCAS OLIVEIRA DO ROSÁRIO
  • Synthesis and characterization of SrMoO4/g-C3N4 prepared via hydrothermal tratment: a study of optical and photocatalytic properties.

  • Advisor : MAURICIO ROBERTO BOMIO DELMONTE
  • COMMITTEE MEMBERS :
  • FABIANA VILLELA DA MOTTA
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • LUÍS PRESLEY SEREJO DOS SANTOS
  • MAURICIO ROBERTO BOMIO DELMONTE
  • Data: Jan 30, 2023


  • Show Abstract
  • The inappropriate dumping of organic effluents in aquatic ecosystems has raised the need for new technologies for water treatment, capable of definitively reducing the concentration of these compounds in the environment. In this scenario, Advanced Oxidative Processes based on semiconductor photocatalysts, such as strontium molybdate (SrMoO4), emerges as an appropriate alternative to promote the degradation of organic pollutants into non-toxic substances. However, SrMoO4 in its pure phase normally has unfavorable photocatalytic properties. A potentially effective strategy to overcome such limitations is the construction of a heterostrtured photocatalyst with the polymeric semiconductor g-C3N4. Thus, SrMoO4 particles and SrMoO4/xg-C3N4 heterostructures were synthesized via a co-precipitation route with additional hydrothermal treatment for different heating times at a fixed temperature of 140 °C. In order to evaluate the influence different percentages of g-C3N4 the SrMoO4 structure and the synergistic effect resulting from the interface interaction between both, the powders were structurally characterized by X-ray diffraction and Raman spectroscopy, in which it was possible to verify the obtaining of the pure phase of SrMoO4 and the composite phase of SrMoO4/xg-C3N4. Optical analysis by ultraviolet visible spectroscopy revealed that g-C3N4 can considerably decrease the SrMoO4 gap, while the heterojunction mechanism estimated for SrMoO4/g-C3N4 suggests an increase in the lifetime of photogenereated loads. Such characteristics indicate the possibility of obtaining a material with improved photocatalytic properties, which were later verified through photocatalytic tests of methylene blue under UV and solar light, with results above 74 and 97%, respectively. In addition, the heterojunctions showed excellent absorption capacity in the middle of the cationic dye system.

2
  • WESLEY EULÁLIO CABRAL CAVALCANTI
  • GLYCEROL CONVERSION IN THE PRESENCE OF ETHANOL USING CATALYST BASED ON CoFe2O4/SBA-15

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • RINALDO DOS SANTOS ARAÚJO
  • TIAGO PINHEIRO BRAGA
  • Data: Feb 2, 2023


  • Show Abstract
  • Glycerol is the main byproduct for obtaining biodiesel, therefore, the growth of its production has caused an increase in the supply of glycerol, drastically reducing its market value. In order to improve the economic efficiency and ecological standards of biodiesel production, attempts have been made to catalytically convert glycerol into bioproducts with higher added value. In this sense, this work aimed to synthesize and characterize the solid based on cobalt ferrite supported on SBA-15 (CoFe2O4/SBA-15) to act as a catalyst in the reaction of conversion of glycerol in the presence of ethanol. The support was synthesized via hydrothermal method using P123 as organic director and TEOS as silica source. While the synthesis of the catalyst occurred through the impregnation of precursors of Fe3+ and Co2+ (Fe(NO3)3 · 9H2O and Co(NO3)2 · 6H2O) via Pechini's method. Characterizations via X-ray diffraction (DRX) and FTIR spectroscopy confirmed the syntheses of SBA-15 and CoFe2O4/SBA-15. Raman spectroscopy allowed the identification of ferrite with a degree of inversion (δ) of 0.4. The redox property of the catalyst was evaluated via the reduction at temperature program (TPR-H2) which showed reduction events above 400°C, referring to the reduction of Co2+ and Fe3+. The N2 physisorption analysis showed a surface area of 372 m2/g and a total pore volume of 0.65 cm3/g for the catalyst, indicating the presence of oxide on the surface and in the mesochannels of the support. Through scanning electron microscopy (SEM) it was confirmed that the support morphology was maintained after the impregnation process. Already from the transmission electron microscopy (TEM) it was observed an average particle size of 6.19 nm for the supported cobalt ferrite. The acid-base properties of the catalyst indicated the presence of weak basic sites via CO2 desorption at programmed temperature (TPD-CO2) and the presence of Lewis acid sites via NO and Pyridine adsorption followed by FTIR analysis. The presence and nature of the acid/base sites will be of fundamental importance for understanding the processes that occur during the glycerol conversion reaction in the presence of ethanol.

3
  • JOYCE CRISTINE ARAÚJO DA SILVA
  • Obtaining Carbon Nanotubes from CH4 using Ni-based catalysts supported on MgAl2O4 substituted with Fe or Mn

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • SIBELE BERENICE CASTELLA PERGHER
  • RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS
  • GILVAN PEREIRA DE FIGUEREDO
  • Data: Feb 3, 2023


  • Show Abstract
  • Obtaining Carbon Nanotubes from CH4 using supported Ni-based catalystsThis work aims to develop nickel catalysts supported on magnesium aluminate substituted with Fe or Mn, using chitosan as chelating agent. For this, the materials were synthesized via microwave-assisted combustion, partially replacing the spinel B site with Fe or Mn, and the impregnation of the active phase was due to incipient moisture. The supports were submitted to X-ray diffraction analysis in order to identify the formed phases and had their specific area determined by BET and the pore distribution calculated by the BJH method. The catalysts were characterized by XRD, infrared spectroscopy (FTIR), field emission scanning electron microscopy (FEG-SEM) and temperature programmed reduction (RTP). From the cracking of methane, the synthesis of carbon nanotubes was carried out, which were evaluated by Raman. In XRD, the 2θ peaks at 36.8, 44.8 and 65.8ºC and in FTIR, the bands at 472 and 682 cm-1 confirm the formation of MgAl2O4. The peaks at 44 and 63º in the XRD were attributed to NiO, indicating that the active phase impregnation occurred. Specific area analysis showed that the supports had a surface area between 16-39 m2/g and a maximum pore volume of 0.06 cm3/g. The SEM-FEG demonstrated that the morphology of the catalysts is modified depending on the doping used. The EDS demonstrated a good dispersion of NiO on the surface of the catalysts. The RTP allowed to evaluate the reduction profile of the catalysts in which strong O Ni/support interactions were observed for Ni/MAQ, Ni/MAF01Q and Ni/MAF05Q samples. Reduction events in the range of 250-500°C were attributed to NiO reduction. Raman confirmed the obtainment of carbon nanotubes.

4
  • ARYANDSON DA SILVA
  • Synthesis of LTA zeolites for CO2 adsorption

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • ADONAY RODRIGUES LOIOLA
  • FABIO GARCIA PENHA
  • LUCIENE DA SILVA SANTOS
  • MARIELE IARA SOARES DE MELLO
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Feb 27, 2023


  • Show Abstract
  • Currently, CO2  is the main gas that causes the greenhouse effect, mainly because it is easily obtained in combustion processes, which is the main form of energy conversion used by humanity and the amount of gas emitted into the atmosphere has increased over time. of the years, therefore, studies that aim to mitigate or end emissions are increasingly present in the scientific community. LTA zeolites synthesized from different silicon sources were then compared, cation exchange was performed on these materials, they were then characterized by x-ray diffraction (XRD), X-ray fluorescence (XRF), analysis of textural properties by adsorption and argon desorption at 77K and then applied to CO2 adsorption at low pressures up to 10 atm at room temperature, compared with model isotherms by Langmuir, Freundlich and Temkin and the best results applied to more extreme conditions, from 5 bar to 25 bar at 200°C, and selectivity tests were carried out in a fixed bed column, with a gaseous mixture of CO2/CH4. From the XRD it was possible to observe the formation of the crystalline phases characteristic of the LTA zeolite, and analyzing the argon adsorption and desorption isotherms it was possible to confirm the cation exchange process by the considerable increase in the specific area and volume of micropores. This increase significantly influenced the adsorption of CO2, as it was possible to observe by the isotherms, where the materials containing calcium absorbed a greater amount than the materials in sodium form. When applied under extreme conditions of temperature and pressure, we see that the materials continue to adsorb with increasing pressure, even at temperatures of 200°C and from the selectivity study, we see that all materials showed good selectivity for CO2, in the CO2/CH4 mixture, adsorbing more than 99% of CO2 and less than 1% of CH4 in 10 minutes.

5
  • CARLOS AUGUSTO LEAL DANTAS
  • Development of Lightweight Slurries Containing Nanosilica for Application in High-Temperature Oil Wells with Low Fracture Gradients

  • Advisor : JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • COMMITTEE MEMBERS :
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • PEDRO TUPÃ PANDAVA AUM
  • RODRIGO CESAR SANTIAGO
  • Data: Feb 28, 2023


  • Show Abstract
  • The cement used in the drilling operation of high-temperature oil wells needs to be added with silica to avoid the process of retrogression of the mechanical resistance of the cementitious matrix that occurs from 110 ºC onwards, as it forms hydration products that are harmful to the cement. In wells with a low fracture gradient, it is necessary to use lightweight cement slurries to avoid the rupture of the rock formation; therefore, cement extenders are used, such as sodium bentonite. However, its use implies the reduction of the compressive strength of the cement with the increase of its concentration. In recent years, the addition of nanosilica in cement slurries has been widely studied, obtaining promising results such as an increase in rheological parameters, a reduction in porosity and permeability, and an increase in compressive strength. Hence, this work aimed to develop lightweight slurries containing nanosilica for application in high-temperature oil wells with low fracture gradients. For this, slurries with densities of 12.5, 13.0, and 13.5 lb/gal, varying the concentration of nanosilica, and standard slurries with sodium bentonite, where all slurries contained 40% crystalline silica. The slurries were assessed regarding their rheological behavior, stability, compressive strength, X-Ray Diffraction (XRD), Thermogravimetry (TGA), and Scanning Electron Microscopy (SEM). The systems considered stable were selected and subjected to curing at 41 °C and 14.7 Psi for 24 hours and for 28 days and under the condition of 180ºC and 3000 Psi for 28 days. According to the rheological findings, the concentration of nanosilica is correlated with an increase in the values of the rheological parameters. Concerning the stability and compressive strength tests, parameters were improved with increasing nanosilica concentration. Finally, nanosilica can be characterized as a water-extending additive, and its application in high-temperature oil well cementing with a low fracture gradient can be a promising alternative.

6
  • JOSÉ VÍTOR DE SOUZA MEDEIROS
  • EVALUATION OF THERMAL AND OPTICAL PROPERTIES OF NOVEL FLUORESCENT 2,4,6- TRIARYLPYRIDINE DERIVATIVES

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • MIGUEL ANGELO FONSECA DE SOUZA
  • RODRIGO CRISTIANO
  • Data: Jun 2, 2023


  • Show Abstract
  • The world has sought to develop new functional advanced material for many applications in the optical-electronic fields, and among them, liquid crystals (LC) are widely employed as fundamental components in screens and displays. This work presents the synthesis and structural characterization as well as the investigation of photo- physical and thermal properties of a new 2,6-bis(4-(dodecyIoxy)phenyl)-4-(4-X-phenyl)pyridines (X = H, 3a; F, 3b; NO2, 3c; 2-thiophen, 3d; Ph, 3e; OCH3, 3f; OC12H25, 3g; carbazole) and 2,4,6-tris(3,4-bis(dodecyloxy)phenyl)pyridine (3h), aiming new fluorescent liquid crystals. These molecules have π-extended heterocyclic nuclei as rigid core and peripheral dodecyloxy chains, being structurally adequate for this proposal. Target molecules 3a-3g were obtained in moderate yielding (33-78%) by a multicomponent protocol based on combination of 1-(4-(dodecyloxy)phenyl)ethanone, 4-X-benzaldehyde and ammonium acetate, in DMF and presence of cobalt chloride. These products were properly characterized by 1H and 13C nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) indicated that, under heating, compound 3g showed a crystal to crystal transition at 60oC, until 95oC, when becomes isotropic liquid. This behavior was also evidenced by POM on cooling. For compound 3h, although a rationalized spherulitic texture was confirmed by POM, formation of mesophase was not evidenced. The pyridine derivatives showed maximum in absorption bands between 258 nm and 377 nm, and fluriescence in the blue/violet region in solution, emission between 370 and 391 nm, and also in the solid state. The colors associate to emission were confirmed using a chromatographic diagram software based on fluorescence data. At this moment, photo-physical and thermal analysis of target molecules are being carried out.

7
  • YURI KAUÃ RODRIGUES DE OLIVEIRA SILVA
  • Evaluation of Ni/Al2O3 Catalysts Modified with B2O3 and Cobalt in the Dry Methane Reforming Reaction.

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • TIAGO PINHEIRO BRAGA
  • RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS
  • VÍTOR RODRIGO DE MELO E MELO
  • Data: Jun 6, 2023


  • Show Abstract
  • Dry reforming of methane (DRM) is a synthetic route for the production of syngas from a binary gas mixture with greenhouse gases (CH4 and CO2). This reaction has garnered significant academic interest due to it’s similarity to the production of synthesis gas from biogas reforming, which shares the same componentes, but with varying ratios of CH4 and CO2. The main challenge regarding this topic is the rapid deactivation of catalysts, primarily caused by the high production of inorganic carbon (coke) that encapsulates the active phase particles and hinders long-term conversion. In this regard, seven catalysts were planned, prepared, and evaluated following the established mixture design. These included one nickel (Ni) catalyst used as a standard, two boron trioxide (B2O3) promoted Ni catalysts, two bimetallic Ni-Cobalt (Co) catalysts, and two B2O3-promoted bimetallic catalysts, all supported on gamma-alumina. The support was synthesized using the microwave-assisted combustion method, employing urea as the fuel. The metals and non-metallic promoter were introduced by co-impregnation with insipid wetness, followed for a subsequent heat treatment at 550 °C for three hours. The catalysts were structurally characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), field-emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). Catalyst activation was carried out at 700 °C for one hour under a hydrogen (H2) flow. Catalytic tests were conducted in a fixed-bed catalytic unit coupled with a gas chromatograph. The materials were tested for 12 hours at a space velocity of 96 L·g-1·h-1. The formed carbon was characterized by XRD and Raman spectroscopy, which revealed lower formation of crystalline carbon with a disorder degree of 1.29 for the sample with a higher amount of B2O3. The carbon content was quantified using thermogravimetric analysis (TGA), demonstrating that the insertion of B2O3 reduced the carbon amount by up to 57.7%. The results indicate high stability, improved activity, and reduced coke deposition for the catalysts containing all three components. Statistical modeling shows a strong correlation between the varied components and catalyst performance, with boron significantly reducing coke formation and cobalt providing activity and stability in terms of sintering. The proposed special cubic predictive model demonstrates high statistical significance, as evidenced by the Fisher test with an Fcalc/Ftab ratio of 41.12.

8
  • ANNE NATÁLIA ALMEIDA DE OLIVEIRA
  • Phytochemical approach and antivenom activity, in silico and in vitro, of saponins and flavonoids from Bredemeyra floribunda.

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • RENATA MENDONÇA ARAUJO
  • LEANDRO DE SANTIS FERREIRA
  • SARAH DE SOUSA FERREIRA
  • Data: Oct 5, 2023


  • Show Abstract
  • Certain species of plants are popularly used to treat accidents with venomous animals and their studies demonstrate interest from the phytochemical point of view, thus contributing to the isolation and identification of biologically active compounds. The genus Bredemeyera, belonging to the Polygalaceae family, comprises species popularly known as "snake root" due to its use as an antivenom. In ad dition to their antivenom properties, they are also known for their expectorant, diuretic and hypotensive properties. The chromatographic study of Bredemeyra floribunda resulted in the isolation of two secondary metabolites, the flavonoid rutin and xanthone, called 1,7-dihydroxy-3,4,8- trimethoxyxanthone and a fraction containing a mixture of two saponins. In view of all this, the objective of this study was to investigate the phytochemical profile of the hydroethanolic extract of the roots of B. floribunda using dereplication through ultra-performance liquid chromatography coupled with mass spectrometry (CLUE-MS) and to evaluate its effects of extract and isolated substances against the main enzymatic  activities  of  the  venom  of  the  snake  Bhotrops  leucurus  in  vitro.  The  CLUE-MS  analysis  of  the  hydroethanolic  extract  of Bredemeyera floribunda roots revealed that flavonoids, xanthones and saponins constitute the most relevant class of secondary metabolites in the extracts. For the enzymatic inhibition studies, extracts and previously isolated substances were tested, for the proteolytic assay it was observed that the proportions 1:25, 1:50, 1:75 and 1:100 (poison:extract, w/w) the extract significantly reduced enzymatic activity. The same way was evidenced in the phospholipase activity, all proportions of the tested extract proved to be effective in inhibiting the enzymatic effect. In the hyaluronidase method, it was demonstrated that the extract was effective in ratios 1:10 and 1:25. These data revealed the antiophidic potential of the extracts by inhibiting the main enzymatic activities of the B. leucurus snake venom, demonstrating that both extracts can be relevant and promising for the treatment of snake bites.

9
  • GABRIELA DA SILVA LEMOS
  • Study of thermal and thermocatalytic conversion of licuri oil  (Syagrus Coronata) using KIT-6 to obtain renewable hydrocarbons

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ANTONIO SOUZA DE ARAUJO
  • EDJANE FABIULA BURITI DA SILVA
  • FABÍOLA CORREIA DE CARVALHO
  • Data: Oct 19, 2023


  • Show Abstract
  • The use of fuels derived from fossil sources has caused major global challenges, and the development of research in search of renewable energy resources is relevant. Thus, the present work aims to evaluate the potential of licuri oil (Syagrus Coronata) to obtain renewable hydrocarbons from its thermal and thermocatalytic conversion using KIT-6 type catalysts supported with nickel and molybdenum. The catalysts were characterized by X-Ray Diffractometry (XRD), Thermogravimetric Analysis (TGA), Fourier Transform InfraRed spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDS). From the characterization of the materials, it was verified that the KIT-6 presented a well-ordered structure and that it remained unchanged after the impregnation of the metals to the support. A thermal and thermocatalytic study was carried out using thermogravimetric data obtained at heating rates of 10, 20, 30 and 40 °C/min, where a greater conversion was noted when the sample was heated more slowly. Through the kinetic study applying the Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) model, it was verified based on the values of the correlation coefficient (R²) that the KAS model best suits the process of thermal and thermocatalytic degradation of licuri oil. The OL, OLK, OLKNi, OLKMo and OLKNiMo samples exhibited, respectively, average apparent activation energy (Ea) of 75.63; 102.49; 78.11; 85.57 and 122.11 KJ/mol. Based on these results, it was verified that the presence of catalysts led to an increase in Ea values in relation to the thermal test of the oil, suggesting the occurrence of polymerization reactions. Thus, the evaluation of the products obtained in the pyrolysis process is important in clarifying the catalytic activity of the materials.

10
  • AMANDA MEDEIROS DE AZEVEDO
  • Photocatalytic decarboxylation of fatty acids for production of drop-in biofuels.

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ARUZZA MABEL DE MORAIS ARAUJO
  • CARLOS ALBERTO MARTINEZ HUITLE
  • LIVIA NUNES CAVALCANTI
  • NATALY ALBUQUERQUE DOS SANTOS
  • Data: Oct 23, 2023


  • Show Abstract
  • The growing concern about the progression of the effects of global warming caused by greenhouse gas emissions (GHGs) over the years has sparked interest in diversifying the energy matrix. In this context, there has been an increase in the demand to produce drop-in biofuels, chemically identical to fossil fuels, to reduce dependence on non-renewable resources and mitigate CO2 emissions. To form a mixture of renewable hydrocarbons compatible with engine structures, the biomass to be used needs to undergo deoxygenation processes, such as thermo-catalytic ones. However, existing methodologies have some operational limitations such as high temperatures, high hydrogen gas pressures, and the need for specific reactors. In this sense, the present work proposes the development of a selective photocatalytic method for deoxygenating fatty acids from vegetable oils under mild conditions, using an organic photocatalyst, at room temperature, in a metal-free process without the use of hydrogen gas. After the optimization of the reaction conditions carried out for a model compound, lauric acid (C12:0), a major component of some vegetable oils, yields of up to 80% were obtained for the formation of undecane. The evaluated parameters included the photocatalyst, hydrogen transfer agent, base, their respective stoichiometries, reaction concentration, light source, reaction time, as well as the performance of control experiments. Subsequently, the reaction scope was analyzed by applying the methodology to other pure fatty acids (capric, myristic, palmitic, stearic, oleic, and linoleic acids), obtaining yields of up to 60% for these species. Furthermore, to assess the robustness of the method, the decarboxylation of bio-derived fatty acids obtained from the hydrolysis of commercial Licuri oil was evaluated, resulting in a conversion of over 90% with high selectivity for the respective hydrocarbons. Thus, this new method emerges as a viable alternative to existing deoxygenation processes for producing mild drop-in biofuels with highly selective formation of Cn-1 hydrocarbons.

11
  • PEDRO FILIPE ALVES CHAVES DE QUEIROZ
  • MECHANOCHEMICAL ACTIVATION TO OBTAIN HIERARCHICAL ZSM-5 ZEOLITE AND APPLICATION IN PLASTIC PYROLYSIS

  • Advisor : VALTER JOSE FERNANDES JUNIOR
  • COMMITTEE MEMBERS :
  • VALTER JOSE FERNANDES JUNIOR
  • ARUZZA MABEL DE MORAIS ARAUJO
  • FLORIVAL RODRIGUES DE CARVALHO
  • Data: Oct 27, 2023


  • Show Abstract
  • Hierarchical zeolites are materials with a combination of micropores, mesopores, and macropores designed to facilitate the diffusion of bulky molecules while maintaining the characteristics of the original microporous zeolite. Hydrotherma l synthesis employs solvent, heat, and time, resulting in higher costs and waste generation. Thus, this research aims to bypass hydrothermal synthesis by utilizing mechanochemical synthesis through the ball milling technique of NH4ZSM-5 zeolite, solvent-free, in conjunction with co-templates: cetyltrimethylammonium bromide (CTMABr) and tetrapropylammonium bromide (TPABr). The grinding time, diameter and number of balls and the rotation scale were optimized to identify the best operational conditions of the ball mill (IKA ULTRA TURRAX TUBE DRIVE – UTTD), for mechanochemical activation of the ZSM-5 zeolite. Data analysis involved X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive X-ray Spectroscopy (EDS). These analyses revealed that the optimal conditions for the ball mill involved employing fifteen steel balls with 6 mm in diameter without the use of solvents. Textural Analysis (N2  Adsorption and Desorption) indicated that only five minutes were necessary to significantly alter the structure and chemical composition, resulting in reorganization through recrystallization and new bonds generated by the silicate and aluminate groups of the catalysts. Data from thermogravimetric analysis of zeolites underscored the importance of templates in intercrystalline mesopore development. The modified catalysts were applied in the pyrolysis of polypropylene and the products were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). It was observed that the zeolite ZSM-5 with mechanochemical activation produced 94% by mass of compounds in the range of hydrocarbons in the range of C6 to C9, similar to gasoline and diesel, with selectivity for mono-aromatic compounds, showing that the material was obtained effective for the production of high value-added sustainable fuels from the conversion of plastics.

12
  • JHONATAN FERREIRA CÂMARA
  • Effect of thiophene on the properties of lead-free perovskite halides for solar cells.

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • AMANDA DUARTE GONDIM
  • RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS
  • ÂNGELO ANDERSON SILVA DE OLIVEIRA
  • SILVIA LETICIA FERNANDES
  • Data: Nov 8, 2023


  • Show Abstract
  • The use of fossil fuels results in the release of greenhouse gases, detrimental to the environment. Hence, there has been increased investment in renewable energies, specifically in solar energy, as it is a clean, noise-free, and abundant source. Perovskite materials are promising candidates for the study of solar energy conversion into electricity due to their wide absorption of solar spectrum light, compositional versatility, defect tolerance, ease of processing, and lower cost compared to silicon used in commercially available solar panels. Therefore, this dissertation aimed to investigate the properties of inorganic perovskite Cs3Sb2I9  (CSbI) using the organic molecule thiophene (C4H4S) in the powder preparation via the anti-solvent method. The purpose was to examine its properties and prepare a photovoltaic device by doctor blade deposition, using a chitosan solution as a dispersant to form films, measuring the capability of these materials to convert solar energy into electrical energy. By producing materials with 0%, 9%, 17%, and 34% (m/m) of thiophene [(CSbI_9), (CSbI_17), and (CSbI_34)], the additive improved crystallinity, suppressed secondary phases, and elucidated the same crystallographic phase. It induced changes in the bandgap (2.23 eV, 2.00 eV, 1.95 eV, and 2.35 eV) and subtle modifications in the precipitate morphology, transitioning from coarse hexagonal plates to smaller needle and leaf-shaped particles with reduced agglomeration. Complementary EDS studies confirmed the profile for the perovskite in  question,  without  revealing  thiophene  components  (in  this  case,  sulfur),  indicating  the absence of  the  additive post-synthesis.  Raman spectroscopy exhibited the same scattering profile for the samples, with sample CSbI_9 showing lower scattering intensity, indicating fewer phonon trap sites. When constructing a microcell with the FTO/TiO2/Perovskite/NiOx/Ag configuration, a power conversion efficiency (PCE) of 0.42% was achieved for the perovskite doped with 9% (Voc: 0.059V; Isc=0.27mA, and FF=19.37%). This was the best result compared to 0.19% with the perovskite containing 17% and 0.06% with 0% thiophene. The reduced gap and fewer phonon trap states due to the electron-phonon effect made CSbI_9 the best-constructed device. The results offer perspectives for the study of additives in modulating the properties of inorganic materials for solar cells and exploring new methods for thin film deposition.

Thesis
1
  • BRUNA LUIZA BATISTA DE LIMA
  • Hydrophobically Modified Carboxymethylcellulose and Its Applicability in Drilling Fluids.

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ANA MARIA DA SILVA MAIA
  • FABRICIO GAVA MENEZES
  • LISZT YELTSIN COUTINHO MADRUGA
  • MARCOS ANTONIO VILLETTI
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Jan 10, 2023


  • Show Abstract
  • Polymers extracted from renewable sources, such as polysaccharides, have attracted increasing interest of academy and industry, in order to obtain additives applicable in different formulations. In the petroleum industry, in particular, the development of new drilling fluids with characteristics similar to those of conventional synthetic drilling fluids, but that attend to environmental requirements, has been attracting the attention of researchers. In this sense, this work has as objective to obtain and characterize hydrophobically modified carboxymethylcellulose (CMC) and to evaluate its potential for application in non-aqueous drilling fluids based on olefin, as rheological modifiers. The products were obtained from the reaction between the carboxylic acid groups of CMC and the amine from dodecylamine, via carbodiimide coupling, with or without the presence of a catalyst. The materials were characterized by spectroscopy in the infrared region (FTIR), solubility tests, dynamic light scattering (DLS) and rheological measurements. The FTIR spectra of the derivatives showed an amide band, proving that the reaction occurred. Through the solubility tests, it was observed that the CMC derivatives, unlike the precursor, showed turbidity in water, due to the hydrophobic groups inserted onto the CMC chains, which associate as a way of protection from the polar environment. This behavior resulted in higher diameter values for the derivatives in water, as observed by DLS. The rheological measurements in water also corroborated with the DLS data, as the viscosity of the derivatives was higher than that of CMC. The addition of salt to the aqueous medium resulted in even higher viscosities for the products. However, the number of hydrophobic groups inserted onto the CMC chains has not yet been enough to make the products soluble in a nonpolar solvent.

2
  • RAFAEL CHAVES LIMA
  • Layered solids structural modifications to obtaining aluminum, titanium, and niobium containing-catalysts.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • ANDERSON JOEL SCHWANKE
  • ANTONIO SOUZA DE ARAUJO
  • CHRISTIAN WITTEE LOPES
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • VERA R. LEOPOLDO CONSTANTINO
  • Data: Jan 19, 2023


  • Show Abstract
  • The layered solids Magadiite, Na-RUB-18, and potassium hexaniobate were hydrothermally synthesized and modified by many methodologies aiming isomorphous substitution and pillaring processes in order to generate potential catalysts. The materials were characterized by different techniques, namely, XRD, elemental analysis by ICP-OES and CHN, FTIR, NIR, DRUV-Vis, Raman spectroscopies, Solid-state MAS  29Si and 27Al NMR, N2 and CO2 physisorption, and FEG-SEM and TEM microscopies. Isomorphous substitutions with Al, Ti and Nb were carried out in the magadiite leading to various coordination sites. Also, some these procedures led to MOR and GIS topologies zeolite crystallization. For pillaring processes, the lamellar solids were previously swollen and verified that each one interacts differently with the intercalant agent. Magadiite was pillaring with pure silica and Al, Ti, and Nb mixed pillars, which present tetra-, penta-, and hexacoordination sites. It was found that to the processes involved metals the methods that promote a better homogenization and delayed the hydrolysis reactions tend to give more tetracoordinated Al and Ti sites, and pentacoordinated Nb sites. Na-RUB-18 was pillared with pure silica pillars and his textural properties were slightly different to the magadiite. Potassium hexaniobate was successfully submitted to silica pillaring giving a new porous double layered pillared material. To the obtained materials were suggested some catalytic reactions.

3
  • DANIELLE LOBO MONTENEGRO
  • Characterization and prediction of adsorption in heterogeneous microporous materials.

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • ANDERSON DOS REIS ALBUQUERQUE
  • DAVI SERRADELLA VIEIRA
  • PEDRO FELIPE GADELHA SILVINO
  • DANIEL VASCONCELOS GONÇALVES
  • JOSÉ CARLOS ALEXANDRE DE OLIVEIRA
  • Data: Jan 24, 2023


  • Show Abstract
  • Molecular simulation is a powerful tool to predict gas adsorption and to characterize microporous materials. The isotherms were calculated by applying the Monte Carlo method in the grand canonical ensemble. A new kernel of N2  isotherms in γ-alumina and SO2  isotherms in activated carbons were present with different pores sizes, dedicated to the characterization of the micropore range of γ-alumina and to predict SO2 adsorption in carbonaceous materials. The representative pore size distribution of γ-alumina and activated carbons samples were calculated with N2 isotherms at 77 K. A complementary characterization of C141 and WV1050 carbons were obtained with CO2 isotherms at 273 K. N2 kernel in slit-pore of γ-alumina presented a better performance in the description of the experimental N2 isotherm than the models based on cylindrical pores, confirming experimental evidence of γ-alumina morphology. Two γ-alumina samples are investigated, and we observe that 12 to 22% of the total volume consists of micropores that are not adequately characterized with approximate cylindrical kernels. For the first time in the literature, the rMD model is used to predict gas adsorption isotherms. The simulated isotherms obtained for the heterogeneous pore model agree with the experimental data and satisfactorily reproduced the adsorption of SO2 at 298 K C141 and WV1050 activated carbons. The enhancement of the characterization prediction should improve the design of suitable microporous materials for different catalysis and adsorption applications and the prediction of toxic gas adsorption isotherms, like SO2, in amorphous carbon through molecular simulation techniques should help researchers who work with adsorption under critical operational conditions to design suitable adsorbent materials for different processes without the need to carry out laborious experimental tests.

4
  • ANDRÉ HERCULANO DE OLIVEIRA
  • Synthesis and thermal-optical properties of aromatic N-heterocycle-based soft molecular materials as potential liquid crystals.

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • EDUARD WESTPHAL
  • FABIO DA SILVA MIRANDA
  • FABRICIO GAVA MENEZES
  • LIVIA NUNES CAVALCANTI
  • MIGUEL ANGELO FONSECA DE SOUZA
  • RODRIGO CRISTIANO
  • Data: Jan 30, 2023


  • Show Abstract
  • In the last decades, functional organic materials have contributed greatly to the advance of electronic devices. In this context, liquid crystals have been broadly employed as screens and displays components in televisions and computers, as sensors, amongst others. At molecular level, liquid crystal are characterized by a rigid nucleus, usually from (hetero)aromatic nature, surrounded by flexible units, usually aliphatic long chains. Such structural features lead to supramolecular organizations able to induce mesophase, the crystal liquid state, characterized by simultaneous solid and liquid properties, such as birefringence and fluidity, respectively. In the search of new N- heterocycle-based mesogens, this work presents the synthesis of three [4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)]phenol (38) and nine 2-phenyl-1H-benzo[d]imidazole (50) derivatives, which were obtained in good yields and properly characterized by IR, 1H NMR and 13C spectroscopies, and had their thermal properties evaluated by POM and DSC. The effect of aliphatic chains in thermal properties of N,O-dialkylated 38 derivatives indicated that decyl and dodecyl chains, 39b and 39c, respectively, induce to SmX mesophase formation under heating, at 0,67-157 oC e 23-130 oC. On the other hand, compound 39a presented a direct transition from crystal to isotropic liquid phases at 108 oC, which may be due to higher attractive interaction between heteroaromatic cores. The derivatives from 50 molecular system were divided into three groups. Two of them were structurally characterized by the presence of chlorine atom in the benzimidazole moiety besides one or two alkoxy chains (8, 10 and 12 carbon atoms)  in the 2-phenyl ring (48a-48c e 47a-47b, respectively). The third benzimidazolic series (43a-43c) is characterized as esterified 4-(1H-benzo[d]imidazol-2-yl)-2-methoxyphenol obtained from reactions with appropriated 4-alkoxybenzoic acids (8, 10 and 12 carbons atoms). All compounds from the first two series, 48a-48c and 47a-47c, presented SmX mesophases. The mesogens derived from 48 presented liquid crystal behavior, with temperatures ranging from 79-91 oC to 128-151 oC, being higher values obtained for the octyl derivatives. Mesophases for 47a-47c  were found from 47-48 oC to 121-132 oC, and lower temperature transitions compared to compounds derived from 48 are coherent to more alkoxy chains. Lastly, at first, esterified derivatives 43 didi not present liquid crystal property. In summary, nine from twelve final compounds herein reported were found to present liquid crystal behavior, including notable low temperature transition and broad mesophase ranges. While for imidazo-phenanthroline derivatives, intermolecular associations are based on π-stacking and Van der Waals interactions, hydrogen bonding must contribute to the intermolecular association of the benzimidazolic derivatives. These results represent a relevant advance for the development of advanced molecular materials, notably liquid crystals.

5
  • SUEILHA FERREIRA DE ANDRADE DE PAULA
  • PYROLYSIS- GC/MS OF SPIRULINA PLATENSIS: EVALUATION OF BIOMASSES GROWN UNDER AUTOTROPHIC AND MIXOTROPHIC CONDITIONS.

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • CRISTIANE FRANCISCA DA COSTA SASSI
  • JANDUIR EGITO DA SILVA
  • MARIA DE FATIMA VITORIA DE MOURA
  • POLLYANA SOUZA CASTRO
  • RENATA MENDONÇA ARAUJO
  • Data: Jan 30, 2023


  • Show Abstract
  • Microalgae are autotrophic microorganisms that fix CO2 with great potential to produce biofuels in a sustainable way, but the bottleneck is the high cost of obtaining biomass. Mixotrophic growth has been presented as an alternative to achieve economic and environmental sustainability. The biomass used in this work comes from autotrophic and mixotrophic cultivation of S. platensis grown respectively in control medium (Zarrouk) and with the addition of cheese whey at different concentrations, 2.5 (M2.5), 5.0 (M5) and 10.0% (M10), and was provided by Pereira [19] to carry out the characterization of biomasses through Elementary Analysis and calorific value. In addition, their thermal stability was evaluated using thermal analysis through thermogravimetry and fast micropyrolysis (Py-CG/MS) at temperatures of 450 °C, 550 C°C and 650 °C in the evaluation of the production of volatile compounds. The pyrolysis of the biomasses obtained in the autotrophic and mixotrophic cultures, was carried out with the purpose of obtaining bio-oil and valuable chemical products. Due to the influence of the culture medium, the biomasses used in this study present different biochemical compositions and this was observed in the obtained results of calorific value, TGA and volatile compounds evaluated by Py-GC/MS at 450°C, 550°C and 650°C. From the results obtained by thermogravimetry, it was possible to observe that the mass loss processes of all the biomasses in our study occurred in a similar way. As for pyrolysis, we had that the M10 sample, due to its lower protein content, formed a smaller amount of nitrogenous compounds by pyrolysis at all evaluated temperatures. There was a reduction of 43.8% (450º), 45.6% (550ºC) and 23.8% (650ºC) in the formation of nitrogenous compounds in relation to sample A. In addition, the temperature also showed a considerable effect on the formation of volatile compounds. The highest yields of nitrogenous compounds, phenols and aromatic and non-aromatic hydrocarbons were observed at 650ºC. Oxygenated and N and O-containing compounds decreased with increasing temperature. Hydrocarbons such as toluene, heptadecane and heneicosan were produced by pyrolysis of S. platensis. Therefore, these biomasses used in this study proved to be attractive for the production of high quality bio-oil and valuable chemicals, requiring an update regarding the content of nitrogenous compounds, through manipulation of growth conditions and process temperature of pyrolysis.

6
  • RICARDO FERNANDES DOS SANTOS
  • Excitation-emission matrix (EEM) fluorescence biospectroscopy combined with 2nd-order classification algorithms for Alzheimer disease’s diagnosis.

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • EDGAR PERIN MORAES
  • HECTOR CASIMIRO GOICOECHEA
  • KASSIO MICHELL GOMES DE LIMA
  • LUCIENE DA SILVA SANTOS
  • MÁRCIO JOSÉ COELHO DE PONTES
  • Data: Jan 30, 2023


  • Show Abstract
  • Alzheimer’s disease (AD) is a neurodegenerative disease responsible for almost 70% of cases of dementia. Dementia, in turn, is the 7th leading cause of death in the world. In recent years there have been significant advances in research to identify AD, however, the methods traditionally used for diagnosis remain invasive, time-consuming, and expensive. Studies with biospectroscopic techniques combined with chemometrics have shown promising results in AD diagnosis, with the possibility of offering a minimally invasive, rapid, and inexpensive method. This thesis presents a new methodological approach for the diagnosis of AD through the analysis of blood plasma from 230 subjects (83 AD and 147 healthy controls) by excitation-emission matrix (EEM) fluorescence spectroscopy combined with second- order classification algorithms. The classification models were validated through the calculation of figures of merit commonly used in clinical studies (sensitivity, specificity and accuracy) and figures of merit that take into account the sample unbalance and the discriminatory power of the models (F2 - score (F2), Matthews correlation coefficient (MCC) and test effectiveness (δ)). The classification models performed in this study were Parallel Factors Analysis with Quadratic Discriminant Analysis (PARAFAC-QDA) and Tucker3 – QDA. The PARAFAC – QDA model obtained 83.33% sensitivity, 100% specificity and 86.21% F2. While the Tucker3- QDA model obtained 91.67% sensitivity, 95.45% specificity and 91.67% F2. Both models showed high overall performance with 94.12% accuracy and 0.87 MCC. The classifiers also showed high efficiency with the mean scores of the classes separated by three or more standard deviations. The wavelength values from both loading profiles of models were used to suggest potential plasma AD biomarkers. Future studies may correlate these wavelengths and the PARAFAC spectral profiles with plasma AD biomarkers and confirm or not our suggestion. The results achieved with the proposed new methodological approach point to a high-performance, blood-based method for the diagnosis/screening of Alzheimer's disease. This method has the advantages of being minimally invasive, fast, inexpensive, non-destructive, and label-free. In addition, it requires a small aliquot of blood plasma and is performed in easy-to-operate equipment.

7
  • GLENDA CRISTINA DA SILVA LOPES
  • MECHANOCHEMICAL SYNTHESIS OF LTA ZEOLITE FROM KAOLIN.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ANTONIO SOUZA DE ARAUJO
  • ISABEL DIAZ CARRETERO
  • LINDIANE BIESEKI
  • LINDOVAL DOMICIANO FERNANDES
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Jan 31, 2023


  • Show Abstract
  • Due to limitations in traditional zeolite synthesis processes, the search for new and improved methods remains a topic of academic and industrial relevance. Solvent-free synthesis techniques have the advantage of being a more sustainable process, in addition to the high yield in product formation. In this way, mechanochemistry has been a growing approach and allows reducing the process to a single step. The ball mill is a suitable equipment for performing mechanochemistry. Ball milling is a simple, reproducible and environmentally friendly method for converting materials to nanometer sizes and has been recognized as an efficient method for optimizing the properties of powder materials. The study and synthesis of zeolitic materials by grinding was carried out. The first study dealt with the grinding of three different types of kaolin, varying speed and grinding time, aiming at application as a source of silicon and aluminum in the synthesis of LTA zeolite. The second study addressed the synthesis of LTA zeolite with calcined kaolin and with ground kaolin varying the speed, milling time and synthesis time. The third and fourth study addressed the synthesis of LTA zeolite from kaolin without pretreatment ground together with the dry reagents and the synthesis of LTA zeolite from kaolin without pretreatment ground together with the dry reagents and an aliquot of water, respectively, by varying the speed, grinding time, and synthesis time. The obtained materials were characterized by XRD and XRF. In the milling process, the rotation speed of 600 rpm during 60 minutes was selected as the most efficient for the amorphization of kaolin, among the conditions studied. Rotation speed of 400 rpm during 30 minutes was selected as the mildest parameter in which variations in the kaolins were perceived. The syntheses were carried out employing the kaolins ground for 30 and 60 minutes with rotation speeds of 400 and 600 rpm. The syntheses performed by mixing reagents directly in the ball mill used the same time and speed conditions as used in the kaolin grinding experiments. The calcination condition employed was not sufficient for complete amorphization of all kaolins studied. Increasing the grinding speed and time influences the further formation of the zeolite LTA. The synthesis performed by mixing the dry reagents directly in the mill has a positive influence on the formation of zeolite LTA, which is obtained at lower milling speed and time conditions.

8
  • FELIPE FERNANDES BARBOSA
  • Catalytic dehydration of glycerol under mixed oxides of CuO/Al2O3/MxOy (M = ZnO or Fe2O3): Insghts on chemistry surface

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • ALEXANDER SACHSE
  • ANDERSON DOS REIS ALBUQUERQUE
  • CRISTIANE HENRIQUES
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: Feb 27, 2023


  • Show Abstract
  • As an alternative to the use of fossil fuels, biofuels have consolidated in the international market. In this sense, biodiesel has become an excellent route, however, in its synthesis, the by-product glycerol is generated. The conversion of glycerol into higher added value products stimulates the application of different possibilities involving heterogeneous catalysis. In this work, the application of a series of oxide catalysts based on Fe, Al, Cu and another on Zn, Al and Cu was tested. XRD results indicate nanometric diameter and the presence of ZnO, Al2O3  and CuO oxides. Raman, Mössbauer and XPS spectroscopy suggest the presence of phases based on Fe2O3, Al2O3 and CuO. The 27Al NMR indicates an octahedral coordination of Al2O3. Whereas materials made of Zn present tetra, penta and hexa coordination in alumina. FTIR with pyridine adsorption revealed high Lewis acidity across the Fe catalyst series. The TPR exhibited the reduction range of the Fe3+  and Cu2+  sites, indicating the appropriate temperature range for pretreatment. N2  adsorption/desorption indicated the presence of micro-mesopores, while the porous morphology was visually observed by SEM and TEM images. Regarding the performance of the catalysts, the best condition had a conversion of 60% of glycerol and 92% of selectivity in the formation of acetol with 17% of coke according to the TG. The interaction between the different Lewis acid sites involved in the mechanisms for acetol and coke formation on the catalyst surface are discussed. Thus, the synergy between the active sites obtained in the pre-treatment with H2, based on the surface maps ρ(r) and V(r), obtained by calculations via density functional theory, indicating that the presence of Cun+  increases dramatically the selectivity in the formation of acetol, a more important characteristic than the high Lewis acidity.

9
  • HELLYDA KATHARINE TOMAZ DE ANDRADE SILVA
  • Development of analytical methodologies based on infrared spectroscopy and chemometrics applied to forensic entomology

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • EDVAN CIRINO DA SILVA
  • FABRICIO GAVA MENEZES
  • KASSIO MICHELL GOMES DE LIMA
  • SIMÃO DIAS DE VASCONCELOS FILHO
  • TATIANA DE CAMPOS BICUDO
  • Data: Feb 27, 2023


  • Show Abstract
  • This thesis presents the development of alternative analytical methodologies based on near infrared spectroscopy (NIRS, from near infrared spectroscopy) and medium (ATR-FTIR, from attenuated total reflectance with Fourier transform infrared) combined with unsupervised chemometric techniques: principal component analysis (PCA) and hierarchical cluster analysis (HCA); variable selection and multivariate classification: principal component analysis with quadratic discriminant analysis (PCA-QDA), successive projections algorithm with quadratic discriminant analysis and genetic algorithm with quadratic discriminant analysis (GA-QDA) applied to forensic entomology. In the first study, NIRS was used for spectral acquisition of nine species of flies with forensic potential (Diptera: Calliphoridae and Sarcophagidae) in two regions of the insect (dorsal and ventral) with the subsequent construction of PCA and HCA models aiming to evaluate the potential methodology in the segregation/grouping of specimens into taxonom ic categories. The best model was achieved from the average dorsal and ventral spectra, observing the segregation of the species Chrysomya albiceps (Wiedemann, 1819), Lucilia eximia (Wiedemann, 1819) and Ravinia belforti (Prado & Fonseca, 1932), the resulting loadings punctuated absorptions associated with O-H, C-O, C-H and N-H stretches, the latter may be associated with chitin (poly-N-acetyl-glucosamine), the olefinic C-H stretches and fundamental for an unsaturated carbon associated with lipid compounds. In the dendrogram, a distinction was observed between specimens by family (Calliphoridae and Sarcophagidae) and genera (Chrysomya (Robineau-Desvoidy, 1830), Lucilia (Robineau-Desvoidy, 1830), Oxysarcodexia Townsend, 1917, Peckia (Wiedemann, 1830) and Ravinia (Robineau-Desvoidy, 1863)), whereas Oxysarcodexia and Peckia species did not present such established groups, but with considerable overlap. In the second study, ATR-FTIR was applied together with PCA-QDA, SPA-QDA and GA-QDA in discrimination of scavenger larvae (Diptera: Sarcophagidae) in groups: control and intoxicated after feeding on carcasses of rats exposed to the pesticide terbufos. The results showed that the proposed methodology has the potential to classify samples with sensitivity and specificity values greater than 90%. Amon g the three models, GA QDA was the best to detect changes in the biochemical composition of larvae exposed to terbufos, successfully classifying intoxication based on five variables and reaching 98.9% sensitivity and specificity. Therefore, the reported results suggest the potential of NIRS and ATR-FTIR spectroscopies combined with multivariate analysis as alternative tools to identify taxonomic properties of flies, such as family and genera, providing rapid evidence for species identity and in the detection of terbufos poisoning in scavenger fly larvae from carcasses of intoxicated rats, respectively.

10
  • AMANDA SAYURE KASUYA DE OLIVEIRA
  • Conversion of glycerol using Zeolite Beta modified with alotate, MAl2O4 (M= Mg or Zn): Effect of physicochemical properties on catalytic stability

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • ANDERSON JOEL SCHWANKE
  • ANTONINHO VALENTINI
  • ANTONIO SOUZA DE ARAUJO
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: Feb 28, 2023


  • Show Abstract
  • The urgency to replace fossil fuels with renewable ones, combined with the growth in biodiesel production and, consequently, glycerol, stimulate research in order to transform biomass-derived products into others with greater added value and, therefore, maintain the production chain. The dehydration reaction of glycerol in gaseous phase using acidic solids is an interesting reaction pathway. To evaluate the viability of this study, catalysts were prepared with different levels of magnesium and zinc spinel dispersed in Beta zeolite and their catalytic properties were analyzed. The different solids were characterized by XRD, FRX, MPE, FTIR, Raman spectroscopy, nitrogen physisorption, SEM-FEG, TPD-NH3 and DRIFTS-pyridine. The Raman and infrared spectra suggested the presence of bands referring to spinels although by XRD the phases were not observed due to their high dispersion and nanometric size. The DRIFTS and NH3-TPD analyzes indicated that the incorporation of spinels modifies the acidic properties regarding the number, type and distribution of the sites. The N2 physisorption tests showed the maintenance of the micro and mesoporous properties of H-BEA, despite the alteration in the specific area and pore volume values. Catalysts with lower spinel content (2%) showed better performances in glycerol conversion and resistance to deactivation when compared to pure zeolite, reaching conversion values of 73.26%. These results are related to the presence of acidic and basic sites in the catalysts. Magnesium-based catalysts, in the glycerol dehydration reactions, favored the formation of acrolein (63.42% for the best material) while zinc-based catalysts produced mostly allelic alcohol (37% for the solid with the best performance) . The reaction pathways for the different products formed, depending on the type of acidic site, were detailed in the proposed mechanisms and correlated with the electrostatic potential maps. Likewise, the reactions for coke formation were described according to the compounds identified by GC-MS after coke extraction.

11
  • SIMONE ALVES SERAFIM ROCHA
  • Contribution to the chemical and biological knowledge of the species: Marsdenia megalantha (Apocynaceae) and Varronia dardani (Boraginaceae)

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • RENATA MENDONÇA ARAUJO
  • FABRICIO GAVA MENEZES
  • SILVANA MARIA ZUCOLOTTO LANGASSNER
  • ANDERSSON BARRISON
  • CALINE GOMES FERRAZ
  • Data: Feb 28, 2023


  • Show Abstract
  • The Caatinga is a unique heritage on the planet; its semi-arid climate allows for immense varieties of landscapes and unique biodiversity. To contribute to the chemical and biological knowledge of the species belonging to the Caatinga flora, as well as to aid in the discovery of new drugs to cure diseases, this study describes the phytochemical study and the investigation of some biological properties of two plant species endemic to this ecosystem: Marsdenia megalantha and Varronia dardani. M. megalantha, known as "mata-calado", has been the target of studies because it causes poisoning in animals after ingestion of its roots. The chemical study of the hydroalcoholic extract of M. megalantha roots allowed the isolation of five compounds: Megalanthosideo A, B and C and 24-methyl-polinast-5, 23-dien-3,15-diol, being reported for the first time in the literature, besides Lanosterol, revealing that this species is a promising source of saponins with pregnane skeleton, substances that present cytotoxic, antidyslipidemic, antioxidant and anti-HIV properties reported in the literature.  V. dardani, popularly known as "moleque-duro", allowed the chemical study of the ethanolic extract of the roots of V. dardani resulting in the isolation and structural identification of two naphthoquinones: the 2-ethoxy-cordiaquinone A, being unpublished in the literature and the Cordiaquinone B. All isolated chemical constituents were characterized by spectroscopic techniques such as hydrogen (NMR1H) and carbon (NMR 13C) nuclear magnetic resonance, including two-dimensional techniques (COSY, HMQC, HMBC and NOESY) and the spectra compared with data available in the literature. The compounds isolated from V. dardani were subjected to cytotoxicity test and they inhibited 50% of the growth of cell lines (IC50) against human tumor cell lines showing respectively IC50 of 2.7 - 4.2 g.mL-1 and 1.0 - 1.4 g. mL-1 for HCT-116 (colorectal adenocarcinoma) and IC50 3.0 - 4.2 g.mL-1 and 1.6 - 2.3 g.mL-1 for MDA-MB-231 (breast adenocarcinoma) respectively, demonstrating a strong potential of cytotoxic activity and stimulating the continuity of this study with perspective in the discovery of anticancer molecules. The essential oil from the leaves of V. dardani, obtained by hydrodistillation, was analyzed, and chemically characterized by Gas Chromatography coupled to Mass Spectrometry (GC-MS) and Gas Chromatography with Flame Ionization Detector (GC-FID). The analysis resulted in the identification of twenty-five (25) chemical constituents, corresponding to a total of 99.9% of the chemical composition of the oil, consisting basically of monoterpenes and sesquiterpenes. This essential oil showed antimicrobial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa and antifungal activity against two yeasts, Candida albicans and Candida parapsilosis. In addition, the essential oil was also subjected to larvicidal bioassays, showing an LC50 of 97.93 (± 1.25). This study contributed to the chemical and biological knowledge of two endemic species of the Caatinga, enabling the discovery of new unknown substances in M. megalantha, besides unprecedented biological assays related to antimicrobial, antifungal, larvicidal and cytotoxic activities in the species V. dardani.

12
  • MARCÍLIO NOGUEIRA DE SOUZA
  • Physical-chemical evaluation of micellar solutions applied in the removal of olefinic filter cake.

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • DENNYS CORREIA DA SILVA
  • JOSE LUIS CARDOZO FONSECA
  • MONICA RODRIGUES DE OLIVEIRA
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Feb 28, 2023


  • Show Abstract
  • In oil well drilling, drilling fluids are used to form a thin layer in the reservoir rock formation, which will prevent migratory flows from the well to the formation or vice-versa. The removal of this thin layer, called filter cake, formed mainly when non-aqueous fluids (paraffinic or olefinic) are used, is of fundamental importance for the inversion of rock wettability to occur and thus ensuring that success of the primary cementing operation. The fluids called flushing fluid are displaced between the drilling fluid and the cement paste. They act through chemical action in the dilution and removal of filter cake. They have dispersing additives (or drilling fluid thinners), detergents, and, when necessary, additives to inhibit clay swelling and filtrate reducers. When they are used in wells containing oil-based fluid, they also contain surfactants to reverse coating wettability and formation from oil-wet to water-wet. Flushing fluids need to be compatible with the cement paste and the drilling fluid, as they can cause a mixture with excessive viscosity capable of reducing the efficiency of displacement of the drilling fluid and, consequently, making the cement adhesion weak, in addition to the mixture cement paste and flushing fluid are resistant to compression within the limits established by standards. There are several works in the literature that prove the efficiency of removing flushing fluids that can be applied in the oil industry. The use of alcoholic micellar solutions and solutions containing mixtures of surfactants, the so-called Blends, are new technologies that have been used as a flushing fluid to remove the olefin-based drilling fluids and promote formation wettability inversion. In this sense, this work developed and characterized new alcoholic micellar systems from ternary diagrams and by blends of surfactants formulated with commercial non-ionic surfactants to be used as a cleaner in a temperature range (30°, 40°, 50°, and 65°C) that simulates the temperature achieved in the drilling of some oil wells and evaluates their behavior in relation to the cloud point in the removal of the filter cake inside the well. A simplex network design using the scheffé polynomial was made to choose the most efficient formulations in relation to plaster removal. For the formulation of Blends containing surfactants in brine, a 2n factorial study was developed to choose the optimum point of Blends of surfactant solutions that were also studied as a flushing fluid. These systems were subjected to the same tests as the previous system, that is, they were studied at a temperature range (30°, 40°, 50°, and 65°C) whose purpose was to verify the filter cake removal efficiency against the Cloud Point, simulating the behavior of these solutions and their behavior inside the well. For both study systems, the best points were used, the variation of the aqueous phase and its conductivity measurements at those temperatures. After this phase, the microemulsion systems and formulated surfactant blends were characterized by the study of filter cake removal efficiency tests, surface tension measurements, droplet diameter, and wettability, while the mixtures between the flushing fluid and the paste of cement were characterized by rheology, fluid compatibility and compressive strength (UCA), and X-ray diffractometry. The two new removal systems studied in this research proved to be efficient in removing the filter cake formed by the olefinic drilling fluid used in drilling wells oil and proved to be a more economical and a cleaner technology.

13
  • GABRIELLA SOUSA DE MELO QUEIROZ
  • Production of renewable hydrocarbons from the pyrolysis of macaúba oil (acrocomia aculeata) using AlSBA-15, Mo/AlSBA-15, HBeta and Mo/HBeta

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ANTONIO SOUZA DE ARAUJO
  • ARUZZA MABEL DE MORAIS ARAUJO
  • EDJANE FABIULA BURITI DA SILVA
  • JUAN ALBERTO CHAVEZ RUIZ
  • Data: Mar 3, 2023


  • Show Abstract
  • In the present work, thermal and catalytic pyrolysis of macaúba oil was carried out in the presence of AlSBA-15, Mo/AlSBA-15, HBeta and Mo/AlSBA-15 catalysts, aiming at the production of renewable fuels in the aviation biokerosene range. The AlSBA-15 catalyst was synthesized by the hydrothermal method and the commercial zeolite HBeta activated by calcination. The materials were characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Fluorescence (FRX) and Scanning Electron Microscopy coupled to Energy Dispersive Spectrometer (SEM/EDS ). The AlSBA-15 catalyst was obtained with highly ordered P6mm hexagonal symmetry. Activation by calcination of HBeta did not compromise its crystalline structure. Impregnations with molybdenum metal were confirmed by FRX and EDS and did not change the structural and morphological characteristics of the supports. The thermal and kinetic studies were carried out through Thermogravimetric Analysis (TGA) at heating rates of 10, 20 and 30°C/min, in the temperature range of 30 to 600 °C and with 10% of catalyst by weight. The bio-oils obtained by thermal and catalytic pyrolysis were characterized by Gas Chromatography coupled to Mass Spectrometry (GC/MS), FTIR, Acidity Index, Density, Viscosity and Moisture Content. In the thermal study, there was an indication of the efficiency of the use of catalysts in the degradation of macaúba oil through the reduction in the initial temperature of degradation. For all catalysts, there was a reduction in the activation energy of the process, especially for the mesoporous catalysts AlSBA-15 and Mo/AlSBA-15. The two kinetic models OFW and KAS were adequate for the methodology used (R² > 0.9). The physicochemical parameters of macaúba oil and its bio-oils were similar to those found in the literature. FTIR analysis confirmed the cracking of macaúba oil. In thermal pyrolysis, maximum yields of 76.59% were reached, while using HBeta and Mo/HBeta yields were 85.95% and 85.02%, respectively. Indicating that the use of catalysts can improve the pyrolysis process. The HBeta, Mo/HBeta, Mo/AlSBA-15 and AlSBA-15 catalysts produced hydrocarbons in the aviation kerosene range (C11-C16) in 90.88%, 90.45%, 71.34% and 20.35%, respectively.

14
  • LUCIO CESAR DANTAS DE MEDEIROS
  • Action of Eucalyptus pyroligneous acid on the ecologically correct synthesis of silver nanoparticles.

  • Advisor : LUIZ HENRIQUE DA SILVA GASPAROTTO
  • COMMITTEE MEMBERS :
  • JOSE LUIS CARDOZO FONSECA
  • JOSÉ ROBERTO SIQUEIRA JUNIOR
  • LUCIANO CASELI
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS
  • Data: Mar 31, 2023


  • Show Abstract
  • The interest in products derived from renewable natural resources has increased in recent years. Concerning nanotechnology, the goal is to employ low-toxicity chemicals resulting from environmentally benign processes. In the present study, we demonstrated for the first time that pyroligneous acid (PA), a compound obtained from the condensation of polluting gaseous emissions generated during the pyrolysis of biomass, functioned concomitantly as  reducing and stabilizing agents in the synthesis of silver nanoparticles (AgNPs). Furthermore, this methodology was also employed for the production of a nanocomposite consisting of AgNPs anchored in cellulose nanocrystals (AgNPs/NC). Through chromatographic analysis (GC-MS) and Raman spectroscopy, it was shown that in alkaline medium oxygenated species contained in PA reduced silver ions to their metallic form. Concomitantly, acetic acid, abundantly present in PA, adsorbed on the surface of AgNPs conferring them electrostatic stability. The AgNPs werespherical in shape with an average size of 16.42 ± 4.62 nanometers, being stable for at least 150 days (zeta potential = -56 mV). In the production of the AgNPs/NC nanocomposite, it was observed that the time for the total stabilization of the AgNPs was drastically shortened and   the average size substantially reduced (5.12 ± 1.59 nanometers). Thermogravimetric experiments demonstrated that the impregnation efficiency of AgNPs in cellulose nanocrystals was greater than 95%. Finally, AP showed activity against Escherichia coli and Staphylococcus aureus bacteria only at its original pH (pH ~ 2.8). However, upon neutralization (pH = 7.5) the bactericidal activity vanished completely. As demonstrated, the actual responsible for the bactericidal effect was acetic acid. When applied at neutral pH, AgNPs and AgNPs/NC showed bacteriostatic activities similar to those reported in the literature. Based on this information, it is concluded that the use of pyroligneous acid in the synthesis of silver nanomaterials is an interesting and promising approach.

15
  • FRANCISCO GUSTAVO HAYALA SILVEIRA PINTO
  • Study of replicas of mesoporous materials obtained from hard template, using CMK-3 as structure template.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • ANTONIO SOUZA DE ARAUJO
  • LUCIENE DA SILVA SANTOS
  • ANNE GABRIELLA DIAS SANTOS
  • EDUARDO RIGOTI
  • Karim Sapag
  • Data: Apr 14, 2023


  • Show Abstract
  • The synthesis of new porous materials can leverage even more areas consolidated by various fields of research and the chemical industry. For this reason, developing new synthesis routes and improving existing ones is of paramount importance for the scientific community. Among the synthesis routes for obtaining mesoporous materials, there are the synthesis routes by soft-template and hard-template. In this work, the hard-template synthesis route was used using CMK-3 as a structural template, CMK-3 is a carbon material with mesopores obtained from SBA-15. The purpose of using CMK-3 as a mold is to obtain new mesoporous materials with a cylindrical pore system that are organized in a hexagonal way. In this work, a study was carried out on the variation of the amount of silicon in different types of synthesis. The obtained materials were characterized with N2 adsorption and desorption at 77 K, X-ray diffraction, Scanning Electron Microscopy and FTIR Spectroscopy. From the results obtained, it was possible to verify the viability of the process for obtaining new mesoporous materials, whether they are pure silicon or containing metals in their structure.

16
  • MÁRCIO CLEIVO DE MORAIS SOUZA
  • Biohydrocarbons from catalytic processes using micro and mesoporous catalysts with Co and Mo

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ANTONIO SOUZA DE ARAUJO
  • ELISAMA VIEIRA DOS SANTOS
  • ANA PAULA DE MELO ALVES
  • JUAN ALBERTO CHAVEZ RUIZ
  • Data: Jun 20, 2023


  • Show Abstract
  • The search for new sources of renewable energy is growing all over the world, this growth is due to the environmental problems caused by the excessive use of fossil fuels that cause a series of damages to the environment. Faced with this problem, the present doctoral work aims to evaluate the use of microporous catalysts of the ZSM-5 type and mesoporous type MCM-41 catalysts impregnated with cobalt and molybdenum metals in the production of biohydrocarbons via rapid pyrolysis of sunflower oil. The studied catalytic materials were characterized by X-Ray Diffraction (XRD), X-Ray Fluorescence (FRX), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) coupled to Energy Spectroscopy. Dispersive (EDS). The referred analyzes indicated that the porous structures were formed with excellence, and were maintained after the impregnation of the metals. Sunflower oil was characterized by physical-chemical analysis, such as: acidity, peroxide, saponification, refraction, free fatty acids and density, and subsequently a thermal and kinetic study of the oil degradation reaction was carried out using catalysts synthesized micro and mesoporous, and based on the free kinetic models proposed by Ozawa Flynn Wall (OFW) and Kissinger Akahira Sunose (KAS). Thermogravimetric analyzes (TGA) of sunflower oil and sunflower oil with catalysts were performed at heating rates (β) of 10, 20, 30 and 40ºC/min, then the data were treated according to the proposed models, obtaining if so values like: activation energies (Ea) for conversion rates (α) 5, 10, 20, 30, 40, 50, 60, 70, 80 and 90%. The results indicated that all catalysts tested showed catalytic activity. For sunflower oil the Ea ranged from 149.9 to 201.6 KJ/mol, for the mesoporous catalysts MCM-41, Mo/MCM-41, Co/MCM-41 and Co-Mo/MCM-41 the Ea were from 121.1 to 143.6, 72.7 to 112.1, 136.5 to 170.6 and 152.2 to 165.4 KJ/mol respectively, and for microporous catalysts HZSM-5, Mo/HZSM -5, Co/HZSM-5 and Co-Mo/HZSM-5 the Ea ranged from 119.5 to 153.6, 114.8 to 146.7, 142.9 to 166.4 and 101.5 to 158, 0 KJ/mol respectively, with emphasis on Mo/MCM-41 and Mo/HZSM-5, which showed the greatest reductions in activation energies (Ea). Both in the OFW model and in the KAS, the methodologies used proved to be adequate (R2 > 0.9). The thermodynamic parameters (A, ΔH, ΔG and ΔS) were also calculated in the reactions of thermal and thermocatalytic degradation of sunflower oil, in which we can highlight the ΔH>0, indicating that it is an endothermic reaction and the ΔG>0, corresponding to a non-spontaneous reaction. The results of the kinetic study were also used as a basis for thermal and catalytic pyrolysis reactions. In the pyrolysis process, the percentages of hydrocarbons formed were as follows: in thermal pyrolysis, 16% were obtained, in catalytic pyrolysis, the percentages of hydrocarbon formation were 28% (MCM-41), 16% (Mo/MCM-41), 21 % (Co/MCM-41) and 45% (Co-Mo/MCM-41). According to the percentages of formed hydrocarbons, in the thermal pyrolysis 53.2% are in the Aviation Biokerosene range and 46.8% in the Green Diesel range. In the catalytic pyrolysis, the presence of the catalysts favored the deoxygenation of the products by the decarbonylation reaction, thus the catalysts MCM-41, Mo/MCM-41, Co/MCM-41 and Co-Mo/MCM-41 presented 8.6 , 0, 0 and 0% in the biogasoline range, 29.4, 24.5, 27.5 and 19.4% in the aviation biokerosene range and 62.0, 75.5, 72.5 and 80.6 % in the range of green diesel respectively.

17
  • FRANCISCO ALÉXIS DANTAS MAIA
  • THERMAL AND CATALYTIC PYROLYSIS OF CRAMBE ABYSSINICA HOCHST OIL USING MCM-41 AND Mo/MCM-41 MOLECULAR SIEVES

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • CARLOS ALBERTO MARTINEZ HUITLE
  • ARUZZA MABEL DE MORAIS ARAUJO
  • ANNE GABRIELLA DIAS SANTOS
  • EDJANE FABIULA BURITI DA SILVA
  • FABÍOLA CORREIA DE CARVALHO
  • JOAO PAULO DA COSTA EVANGELISTA
  • Data: Jun 27, 2023


  • Show Abstract
  • The use of renewable fuels to replace fossil fuels has become essential for the preservation of the environment. Therefore, the main aspects of Crambe Abyssinica Hochst, the potential of this raw material for the production of biofuels, and its oil are discussed and evaluated in this work. This crop is already used in industry to obtain various products, including biodiesel, bringing expectations of producing new biofuels. Experimentally, approximately 30% oil was obtained from crambe seeds by extraction using soxhlet. A kinetic study through thermal and catalytic decomposition, with the mesoporous sieves MCM-41 and Mo/MCM-41 by thermogravimetric analysis (TGA/DTG) was carried out using the mathematical methods Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira- Sunose (KAS). Lower Activation Energy (Ea) values were obtained with Mo/MCM-41, showing the importance of the metal in the active site of the catalytic material, both in the OFW and KAS methods. The corresponding catalysts used in this process were characterized by XRD with well defined Miller index peaks. In the FRX analysis, molybdenum impregnation was observed in the form of MoO3. The thermal and catalytic pyrolysis of the same material in the proportion of 88% of the oil with 12% of the catalysts showed that the catalytic pyrolysis with Mo/MCM-41 produced 41.12% of hydrocarbons with a yield of almost 75%, considered a good result . Finally, the production of heavy gasoly (C18 – C25) among the hydrocarbon fractions formed was consistent with expectations, as the major acid present in crambe oil is erucic, which contains 22 carbon atoms.

18
  • ISABELLE MARIANE DE LIMA FERREIRA
  • Production of renewable hydrocarbons from the microalgae Monoraphidium sp.

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ANTONIO SOUZA DE ARAUJO
  • CARLOS ALBERTO MARTINEZ HUITLE
  • EDJANE FABIULA BURITI DA SILVA
  • FABÍOLA CORREIA DE CARVALHO
  • Data: Jul 26, 2023


  • Show Abstract
  • The energy potential of the microalgae of the species Monoraphidium sp. was exploited as a raw material for the production of renewable hydrocarbons. For this, the biomass was submitted to physical-chemical pre-treatments with the objective of facilitating the intracellular access of the microalgae. Renewable hydrocarbons from treated biomass were obtained through thermal and catalytic pyrolysis processes in the presence of the HZSM-5 catalyst. The HZSM-5 zeolite was synthesized and characterized by X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA/DTG), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Determination of acidity by base adsorption method (n-butylamine). XRD analyzes confirmed the formation of an MFI-like crystalline structure, with patterns similar to those defined by the International Zeolite Association (IZA). The acidity analysis showed the presence of acidic sites in the zeolite necessary for catalytic pyrolysis reactions. The kinetic parameters involved in the pyrolysis reactions of microalgae biomass were estimated through the development of the Ozawa-Flynn-Wall (FWO) and Kissinger-Akahira-Sunose (KAS) models, with the aid of thermogravimetric analysis (TGA/DTG) in the ratios of heating 10, 20, 30 and 40 °C/min. In which, it was evident that the two models generated precise kinetic data that reflect the thermal conversion of the biomass, resulting in average activation energy values of 104.2 and 122.2 kJ/mol (FWO) and 99.96 and 118, 2 kJ/mol (KAS). The pyrolysis led to the formation of the liquid product, bio-oil that was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography Coupled with a Mass Spectrometry Detector (GC-MS). The chemical composition by CG-MS showed that the bio-oils produced are renewable hydrocarbon sources that can be precursors of biofuels, as they have hydrocarbons in the C6-C20 range, which include gasoline, diesel and aviation kerosene.

19
  • LETÍCIA GRACYELLE ALEXANDRE COSTA
  • Application of Electrochemical Oxidation for the generation of strong oxidants, generation of value-added products, and degradation of Paracetamol, Caffeine, and Olanzapine in synthetic effluents

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • JOSÉ EUDES LIMA SANTOS
  • JOÃO MILLER DE MELO HENRIQUE
  • Data: Jul 27, 2023


  • Show Abstract
  • Electrochemical wastewater treatments are facing a paradigm shift, instead of achieving complete mineralization of organic pollutants researchers are seeking to give economic value to the products generated during the degradation process. One of the products that are generated in the electrochemical oxidation process are volatile fatty acids. These acids are commodities used in various industrial segments such as the food, textile, and pharmaceutical industries. For this reason, this work proposed to evaluate the efficiency of electrochemical oxidation for the degradation of pharmaceutical compounds, trying to find the best conditions both for the removal of organic pollutants and for the electrogeneration of volatile fatty acids. The results achieved are divided into two chapters. The first chapter presents the evaluation of the oxidizing power of the electrogenerated Persulfate and Peroxophosphate solutions for ex situ application. It was observed that the increase in current density is proportional to the increase in oxidant concentration. In the ex situ oxidation process, a reduction of 46.66% for Persulfate and 47.15% for Peroxophosphate was achieved in the degradation of Paracetamol at a concentration of 20 mg L-1. The best condition for this type of application was when the lowest v/v volume ratio of oxidant was used (v/v = 0.5).  The second chapter presents the results found in the electrochemical oxidation of pharmaceutical compounds. The experiments were performed in a cell using a Boron Doped Diamond (DDB) anode, using 0.5M sulfuric acid and sodium sulfate as supporting electrolyte. The drugs paracetamol, caffeine and olanzapine were used as organic contaminants. The electrochemical degradation and acid formation process was monitored by High Performance Liquid Chromatography. It was possible to observe that in sulfuric acid medium the degradation of the compounds was achieved faster. Experiments with perchloric acid were carried out under the same condition to evaluate the influence of the sulfate radical on the degradation. By comparing the experiments, it was proven that the sulfate radical is mainly responsible for the process. The results of Total Organic Carbon showed that although there was complete degradation of the initial pollutant the organic matter present in the effluent was not completely consumed, indicating that there was the production of new organic products. Through chromatographic analysis, it was verified the emergence of acetic acid, formic acid and oxalic acid in the experiments with sulfuric acid as electrolyte. As for the experiments with sodium sulfate, acetic, formic, tartaric, and salicylic acids were observed.  Toxicity experiments with lettuce seeds were performed to see the possibility of reusing the effluent after treatment for agriculture. Only the seeds that were watered with the sodium sulfate treated effluent germinated. It is concluded that electrochemical oxidation is an efficient process for both the generation of oxidant species for in situ and ex situ applications, and for the electrogeneration of carboxylic acids.

20
  • GLEILSON DE FRANÇA VIEIRA
  • APPLICATION OF ELECTROCHEMICAL TECHNOLOGIES AS AN ALTERNATIVE FOR THE TREATMENT OF BEAUTY SALON EFFLUENTS

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • AMANDA DUARTE GONDIM
  • DANYELLE MEDEIROS DE ARAUJO
  • INALMAR DANTAS BARBOSA SEGUNDO
  • JOÃO MILLER DE MELO HENRIQUE
  • Data: Jul 28, 2023


  • Show Abstract
  • One of the advanced oxidation electrochemical processes, also known as: anodic oxidation, is quite efficient in treating wastewater that contains different organic contaminants. In this scientific project, the effluent was collected during a normal day in a beauty salon located in the city of Natal, Brazil. This beauty salon effluent was treated using electrochemical oxidation without any previous treatment and its initial physical-chemical analysis showed a chemical oxygen demand (COD) of 1612 mg O2 L–1, turbidity of 477 NTU and the presence of trace-level metals such as iron, copper, chromium, and zinc (0.1; 0.03; 0.02; 0.02 L–1, respectively). The experimental analyzes were carried out in a laboratory-scale plant, using an electrochemical flow cell consisting of a circular stainless steel plate as cathode and another containing boron-doped diamond (BDD) as anode, both with an active surface of 69.4 cm2, separated by a distance of 1.7 cm. For each experiment, 1.2 liters of contaminated effluent was placed in the reservoir tank which was recirculated through the reaction compartment cell. Electrolyses were performed applying 10 and 30 mA cm–2, using different electrolytes (NaCl or Na2SO4) and concentrations (0.08 and 0.16 M). The experiments were conducted for 360 minutes and samples were collected at specific time intervals. Comparing the supporting electrolytes, NaCl performed better at a high concentration (0.16 mol/L). BDD electrodes are known to be efficient in promoting persulfate and sulfate radical generation from SO4–2 in the bulk solution, as well as reactive species based on the oxidation of Cl- ions. However, the formation of chlorinated species when NaCl is present in higher concentrations, combined with the generation of hydroxyl radicals on the anode surface, seems to be the main degradation route in this study. Furthermore, the low current density ensures better charging efficiency compared to the higher j, as the low j promotes better and efficient oxidation with less parasitic reactions. The addition of electrolytes is mandatory in order to obtain a better efficiency in energy consumption. Without salt to improve the conductivity of the solution, more than 100 kWh m–3 are consumed, while with the sulphate/chloride-based electrolyte this value decreases to approximately 20 kWh m–3. Under the best conditions (0.16 M NaCl, 10 mA cm–2), metals are eliminated from the effluent, and turbidity and COD decrease to 92 and 72%, respectively. The results prove that a simple treatment before release can lead to a less refractory effluent in the public sewage system.

21
  • ERIVALDO PAULINO DA COSTA
  • Studies of the mesomorphic and photophysical properties of 4-(quinoxalin-2-il)phenyl 4-alkoxybenzoates and photophysical investigation of alkoxy (E)-3-styrylquinoxalin-2(1H)-one derivatives

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • MIGUEL ANGELO FONSECA DE SOUZA
  • ANDRÉ ALEXANDRE VIEIRA
  • FABIO DA SILVA MIRANDA
  • RODRIGO CRISTIANO
  • Data: Jul 31, 2023


  • Show Abstract
  • The development of functional organic materials has proved relevant to many fields. Liquid crystals are very relevant to optical electronics industry, as well as fluorescent compounds, which are commonly relevant in the development of sensors. The present thesis is divided into two main parts: the first one is centered in the study of liquid crystal properties of 4-(quinoxalin-2-yl)phenyl 4-alkoxybenzoates (QX1, QX2, DMQX1 e DMQX2). These target-compounds were obtained in good yields from four-step protocols and properly characterized by spectroscopic techniques. All quinoxaline derivatives were verified to present liquid crystalline behavior with mesophases ranging up to 112 oC, which were identified as both nematic and smectic mesophase, except compound DMQX1, which was a nematic liquid crystal. IN general, structural features do not affect considerably the mesomorphic behavior of these compounds, which were properly characterized by polarized optical microscopy based on classical Schieleren (nematic) and fan-shaped (smectic) patterns, among non-conventional textures. Exact phase transition temperatures were verified by differential scanning calorimetry. In the second part of this thesis, photophysical properties of alkoxy-(E)-styrylquinoxalin-2(1H)-one derivatives (SQX1-SQX3) were investigated. The reversible cis-trans isomerism of these compounds was studied in different organic solvents (methanol, acetonitrile, dichloromethane and hexane) and in aqueous medium by UV-Vis and fluorescence spectroscopies. Also, induced aggregation effect was studies by addition of water to solutions of SQX derivatives in polar solvents, including to verify the possibility of [2+2] cycloaddition in solution. Structural features are under discussion, including data obtained from theoretical calculations, in attempt to justify the photophysical properties of these compounds in different conditions.

22
  • JAQUELINE FERREIRA DE MELO
  • Industrial and electronic waste as an alternative for manufacturing sustainable electrochemical sensors: applications in the determination of clinically and environmentally relevant species

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • ANA PAULA SILVEIRA PAIM
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • LUCIENE DA SILVA SANTOS
  • POLLYANA SOUZA CASTRO
  • SUELY SOUZA LEAL DE CASTRO
  • Data: Aug 1, 2023


  • Show Abstract
  • The increase in solid waste generation demands the search for solutions contributing to responsible waste management, minimizing environmental impact, and adding value to these materials. Several strategies can be employed in using these waste materials, including manufacturing low-cost electrochemical sensors. This work focused on developing sustainable electrochemical sensors through the reuse of solid waste for the quantification of the paracetamol and isoniazid in pharmaceutical formulations, heavy metals lead and cadmium in aqueous media. Two main approaches were explored: using carbon nanomaterials obtained from food industry waste and microchips from electronic waste. In the first approach, reduced graphene oxide (r-rGO) was synthesized and used to modify a glassy carbon electrode (r-rGO/GCE), applied in the determination of paracetamol with recovery rates of the active ingredient within the established limits for quality control. In the second approach, microchips were employed in the fabrication of an array of gold microelectrodes (Au-µEA), modified with a bismuth film (BiF/Au-µEA), and applied in the detection of Cd(II) and Pb(II), with evaluation and optimization of the effects of variables that influence the voltammetric response through experimental designs. The findings demonstrated that the developed sensor proved to be suitable for the detection of Cd(II) and Pb(II), exhibiting a linear response for Cd(II) in the range of 0.5 to 13 µmol L−1 and for Pb(II) in the range of 1.5 to 13 µmol L−1. A third approach involved the modification of the microchip surface with nanoporous gold structures (NPG/µEA) to quantify the drug isoniazid. The modified sensor showed higher electrocatalytic activity than conventional gold microelectrodes, enabling the quantification of the analyte in the range of 10 to 300 µmol L−1. Thus, the employed electroanalytical methodologies demonstrated the feasibility of developing electrochemical sensors through the reuse of solid waste. These sensors contribute to waste reduction, more efficient resource utilization, and the promotion of a sustainable approach in the manufacturing of analytical devices.

23
  • ERNANI DIAS DA SILVA FILHO
  • Sorption of emerging contaminants in magnetic composites and chitosan particles

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • ANDARAIR GOMES DOS SANTOS
  • JOSE LUIS CARDOZO FONSECA
  • JOÃO MARIA SOARES
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Aug 11, 2023


  • Show Abstract
  • The pollution of water resources caused by the textile industry and the improper disposal of medicines are serious environmental problems that require immediate attention. Dyes used in the textile industry are highly soluble in water, contaminating water resources and making removal difficult. On the other hand, improper disposal of medicines can contaminate soil and water, representing a significant risk to public health and the environment. These emerging contaminants are being detected at increasing levels in the environment and which still do not have regulations or established control standards. It is crucial that the population is aware of the risks associated with the inappropriate disposal of medicines and that they take steps for their safe and responsible disposal, and through programs to collect expired or unused  medications.  In  this  context,  this  thesis  proposes  the  study  of  the  sorption  of  drugs  sodium  cromoglycate  and  tetracycline  hydrochloride  on magnetic composites, and the development of a numerical method applied to the adsorption of dyes, acid blue 260 (AA), and methyl orange (AM), on crosslinked chitosan to individually and simultaneously identify the concentration of these dyes in aqueous solutions. For this purpose, techniques such as thermogravimetric analysis, molecular absorption spectroscopy in the ultraviolet and visible region, infrared absorption spectroscopy, X-ray diffraction, and adsorption equilibrium studies were employed. The study on drugs revealed that sorption occurred in multiple layers, reaching saturation at concentrations of 0.2 mmol of drug per gram of composite for tetracycline hydrochloride (HTCCl) in both positive and negative magnetic composites. The anionic drug was adsorbed with similar intensity in both composites, with saturation in the negatively charged composite achieved at a value of approximately 0.05 mmol per gram of composite. The Gibbs free energy of adsorption was estimated under dilute solution conditions, ranging from ‒17 to ‒3 kJ/mol. The analysis of thermal degradation kinetics using the isoconversional approach revealed that the presence of magnetite in the magnetic composites reduced the apparent activation energy. Values obtained reached up to 400 kJ/mol for the degradation of the organic phase. This phenomenon demonstrated that magnetite increased the surface area available for drug adsorption. As for the developed method applied to the dyes, it demonstrated more effective sorption for AA, which could be characterized by determining different isothermic parameters, estimation of the Gibbs free energy of adsorption as well as competitive sorption by itself.

24
  • VASCO DE LIMA PINTO
  • RENEWABLE HYDROCARBON PRODUCTION VIA THERMO-CATALYTIC PYROLYSIS OF BOVINE TALLOW USING MESOPOROUS METAL OXIDE CATALYSTS.

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • TIAGO PINHEIRO BRAGA
  • PEDRO NOTHAFT ROMANO
  • EDJANE FABIULA BURITI DA SILVA
  • FELIPE FERNANDES BARBOSA
  • NATALY ALBUQUERQUE DOS SANTOS
  • Data: Sep 4, 2023


  • Show Abstract
  • The need to explore new energy sources has escalated due to the issues stemming from the utilization of fossil fuels, such as acid rain, the greenhouse effect, and global warming. These concerns have significant societal implications, imperiling human survival and long-term sustainability. In this doctoral thesis, an investigation was conducted on mesoporous MCM-41 catalysts integrated with metallic oxides (cobalt, nickel, and molybdenum) to produce renewable hydrocarbons from bovine tallow. The raw material was procured from the Mossoró Industrial Slaughterhouse and subjected to physicochemical characterization. The synthesized catalysts were subjected to structural, chemical, and morphological analyses through X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Fourier-Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS). These analyses verified the preservation of porous structures after the incorporation of metallic oxides. Activation energies of the catalysts were determined using the isoconversional methods proposed by Ozawa-Flinn-Wall (OFW) and Kissinger Akahira Sunose (KAS). This was based on thermogravimetric analyses of bovine tallow and its mixtures with the catalysts, employing heating rates (β) of 10, 20, and 30°C/min and conversion rates (α) of 5, 10, 20, 30, 40, 50, 60, 70, 80, and 90%. The catalysts synthesized in this study, according to both methods, demonstrated effectiveness in lowering the activation energy (Ea) in the thermo-catalytic degradation reaction of bovine tallow. The Ea for the thermal degradation of bovine tallow exhibited variations of 178.7 to 199.1 kJ/mol (OFW) and 176.5 to 197.5 kJ/mol (KAS), respectively. In the presence of the MCM-41, Co/MCM-41, Mo/MCM-41, Ni/MCM-41, CoMo/MCM-41, NiMo/MCM-41, and NiCo/MCM-41 catalysts, variations ranged from 143.1 to 156.0, 146.9 to 165.2, 142.5 to 151.7, 145.5 to 165.9, 161.4 to 166.0, 171.8 to 180.4, and 148.2 to 170.0 kJ/mol for the OFW model, respectively. For the KAS model, the variations were 139.0 to 152.2, 143.0 to 162.0, 138.4 to 147.8, 134.7 to 154.7, 158.1 to 163.3, 169.2 to 177.4, and 144.4 to 167.0 kJ/mol, respectively. Among the catalysts used in the kinetic study, Mo/MCM-41 stood out, exhibiting a reduction of approximately 24% in Ea for the raw material according to the OFW model and about 25% according to the KAS model. Both models used yielded satisfactory results, with R2 values above 0.95, confirming the reliability of the methods. These results were pivotal in obtaining parameters for thermo-catalytic pyrolysis. The thermal pyrolysis reaction of bovine tallow generated a high percentage of hydrocarbons (31.76%). However, this percentage increased with the addition of catalysts to the reaction process. Thus, thermo-catalytic pyrolysis of bovine tallow produced 32.71% hydrocarbons using MCM-41, 76.18% with Ni/MCM-41, 43.72% with Mo/MCM-41, 57.86% with Co/MCM-41, 63.55% with NiMo/MCM-41, 74.60% with CoMo/MCM-41, and 84.99% with NiCo/MCM-41. Based on the percentage of hydrocarbons formed in thermal pyrolysis, the production was found to be 52.17% in the aviation bio-kerosene range, 70.40% in the green diesel range, and 14.64% of hydrocarbons with chains above C24. On the other hand, thermo-catalytic pyrolysis favored deoxygenation through decarboxylation, resulting in an even greater percentage of hydrocarbons, particularly in the green diesel range. The use of MCM-41, Ni/MCM-41, Mo/MCM-41, Co/MCM-41, NiMo/MCM-41, CoMo/MCM-41, and NiCo/MCM-41 catalysts yielded, respectively, 51.02%, 34.00%, 38.63%, 42.81%, 32.49%, 36.80%, and 40.03% in the aviation bio-kerosene range and 87.94%, 88.56%, 83.03%, 90.55%, 98.44%, 95.67%, and 93.27% in the green diesel range. Therefore, catalytic pyrolysis of bovine tallow presents itself as a promising alternative for bio-oil production, with a high production of hydrocarbons instead of oxygenated compounds, thus remaining a significant raw material in biofuel production and minimizing environmental impacts arising from its generation through the use of catalysts impregnated with metallic oxides.

25
  • ANDREY COSTA DE OLIVEIRA
  • Removal of microplastic in water through microemulsion-treated adsorbents

  • Advisor : TEREZA NEUMA DE CASTRO DANTAS
  • COMMITTEE MEMBERS :
  • JOSE LUIS CARDOZO FONSECA
  • JOSÉ RIBEIRO DOS SANTOS JÚNIOR
  • MARIA CARLENISE PAIVA DE ALENCAR MOURA
  • TAMYRIS THAISE COSTA DE SOUZA
  • TEREZA NEUMA DE CASTRO DANTAS
  • Data: Sep 13, 2023


  • Show Abstract
  • The accumulation of plastics in the environment is increasingly becoming a global concern. As part of the UN report of October 2021 and other important organizations, the need to discuss the issue and seek solutions is noticeable. Among the impacts of these materials, microplastics (particles smaller than 5 mm) have been gaining prominence due to their often imperceptible presence in the environment. Because, in the oceans, they are mistaken for food by the fauna and are often not properly removed in wastewater treatment plants (WTP). Thus, this work researched ways to remove this contaminant from effluents. The way studied was through the use of adsorbents treated with surfactants using decantation to separate them. According to the structure of the surfactant and the adsorbents, these could have some interaction with the microplastics, making their extraction possible. Among the surfactants analyzed, the Tween 80 was chosen because, in addition to low toxicity, it presented efficient interaction with plastic, explained by its chemical structure, proven via FTIR analysis. The effluent used in the tests was obtained through the contamination of distilled water by synthetically acquired microplastics. However, they were compared through the FTIR spectrum with real microplastics, taken from the UFRN WTP. Furthermore, five adsorbents were chosen to be treated with microemulsions having Tween 80 as a component: bentonite, diatomite, coconut, sugarcane, and banana peel bagasse. To measure the amount of microplastic that would be extracted, it was necessary to construct a calibration curve. It was done through the FTIR spectrum of different masses of plastic versus the peak area that varied with absorbance. According to the adsorption tests, carried out for each of the five adsorbents with and without treatment and with the aid of the NOAA method to separate the microplastics from the adsorbents after removal, it was found that the banana peel bagasse presented the highest efficiency among the untreated adsorbents: 70%. Among treated products, sugarcane bagasse had almost 80% of plastic removed. Therefore, it is observed that adsorption can be a viable method for the removal of microplastics in water.

26
  • FERNANDO RODRIGO DANTAS FERNANDES
  • Development of silicon-cerium and silicon-titanium photocatalysts for the application in the photodegradation of Rhodamine B.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • ANTONIO SOUZA DE ARAUJO
  • ADONAY RODRIGUES LOIOLA
  • ANNE GABRIELLA DIAS SANTOS
  • MARIELE IARA SOARES DE MELLO
  • Data: Sep 18, 2023


  • Show Abstract
  • The objective of this work was to develop mesoporous nanospheres composed of Silicon-Cerium and Silicon-Titanium through the soft-template method for later application in the photodegradation of Rhodamine B. The synthesis methodology of the photocatalysts basically consisted of using CTAB micelles as a template soft, and sources of silicon, cerium and titanium for the composition of the inorganic structure in the formation of materials. The syntheses were performed using different Si/Ce and Si/Ti ratios in order to evaluate the influence of the amount of metals in obtaining the nanospheres. The photocatalytic tests were carried out using a Rhodamine B solution exposed to a mercury vapor lamp (125w), using 50 mg of catalyst for each reaction in a total reaction time of 180 min. Aliquots were collected throughout the reaction time to be later analyzed in a UV-vis spectrophotometer. The obtained materials were evaluated in structural, textural and morphological character, through the techniques of DRX, FRX, EDS, Adsorption and Desorption of N2 and SEM. The Si-Ti nanospheres did not show diffraction peaks referring to any phase of titanium oxide, indicating that the metal is actually found in the structure of the nanospheres, however for Si-Ce materials it is noticed that high amounts of Cerium can lead to unwanted CeO formation. SEM images demonstrated the formation of well-defined spheres, for both metals, with diameters between 50 and 400 nm. A uniform scattering of Ce and Ti was observed in all materials, which indicates that these metals are actually participating in the composition of the inorganic structure of the nanospheres, corroborating the results of XRD. The proposed soft-template method proved to be effective, enabling the synthesis, in a short time, of Si-Ce and Si-Ti photocatalysts. The photocatalysts showed significant activity in the degradation of Rhodamine B, with Si-Ti-based materials showing the best activity, with reductions of more than 60% of the contaminant being observed. In addition to the photocatalytic activity, the materials also demonstrated a good adsorption capacity in the first 30 minutes of reaction.

27
  • ANNE BEATRIZ FIGUEIRA CÂMARA
  • Development of Analytical Methodologies Based on Advanced Chemometric Tools Coupled with Spectroscopic Techniques for Screening and Quantifying Fossil Fuel Adulteration.

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • DANIELE CRISTINA MUNIZ BATISTA DOS SANTOS
  • ANA CAROLINA DE OLIVEIRA NEVES MENEZES
  • EDGAR PERIN MORAES
  • KASSIO MICHELL GOMES DE LIMA
  • LEONARDO SENA GOMES TEIXEIRA
  • LUCIENE DA SILVA SANTOS
  • Data: Sep 21, 2023


  • Show Abstract
  • Fuel adulteration poses a significant global issue as it involves the illicit use of tax-exempt substances that often go undetected, even during the screening of petroleum products. This illegal practice has far-reaching implications, including environmental pollution, engine damage, health risks, and government tax evasion, leading to illicit gains for those engaged in fraudulent activities. Typically, fraudsters employ non-standard substances that exhibit similar properties and miscibility with fuels, such as kerosene, and residual vegetable oils, making their detection challenging using conventional physicochemical methods employed in the market. In light of these challenges, this research aims to develop advanced analytical methodologies utilizing cutting-edge chemometric tools. By leveraging these techniques, we seek to enhance the screening and quantification of fuel adulteration, enabling more accurate and efficient identification of tax-exempt substances in petroleum derivatives. The outcomes of this study will contribute to combating this pervasive issue and safeguarding the environment, engines, public health, and government revenue. For this, 60 samples of diesel and 98 samples of JET-A1 were applied to simulated the adulteration process with kerosene solvent (KS) for the application of chemometric models couped to spectroscopic techniques. The classification algorithms enabled classifying the blends according to the IR absorption bands assigned to oxidation products, such as phenols and carboxylic acid, with high accuracy and 100% sensitivity and specificity for both diesel and JET-A1. MCR-ALS and PLS regression were able to detect and quantify KS in the fuels with high accuracy (RMSEP<1.64%; R2>0.995). MCR-ALS with area constraint and PARAFAC combined with excitation emission matrix (EEM) fluorescence spectroscopy allowed the quantification of JET-A1. Furthermore, PARAFAC algorithm also quantified the content of KS with high accuracy (RMSEP = 5.36%). MCR-ALS model stood out for recovering the spectral profile of the adulterants by segregating it from the fuel spectra. In addition, the developed methodology had an overall performance superior than the traditional physicochemical methods using to screen the adulteration, showing its potential to future application for in loco fuel quality control.

28
  • EDUARDO AUGUSTO DA SILVA DINIZ
  • COMPUTATIONAL EVALUATION OF Bothrops brazili PHOSPHOLIPASE A2 INHIBITORS.

  • Advisor : DAVI SERRADELLA VIEIRA
  • COMMITTEE MEMBERS :
  • ANDERSON DOS REIS ALBUQUERQUE
  • DAVI SERRADELLA VIEIRA
  • EUZEBIO GUIMARAES BARBOSA
  • GUTTO RAFFYSON SILVA DE FREITAS
  • NORBERTO DE KASSIO VIEIRA MONTEIRO
  • Data: Sep 29, 2023


  • Show Abstract
  • Myotoxicity caused by snakebite envenoming emerges as one of the main problems of ophidic accidents as it is not well neutralized by the current serum therapy. A promising alternative is to search for efficient small molecule inhibitors that can act against multiple venom components. Phospholipase A2 (PLA2) is frequently found in snake venom and is usually associated with myotoxicity. Thus it represents an excellent target for the search of new treatments.  Initially, the interaction of PLA2 with membrane models composed of 1-palmitoyl-2-oleoyl phosphatidylglycerol (POPG) and 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) was designed to identify the most important protein residues for interaction with the membrane. Subsequently, the effect of temperature on the inhibition of the catalytic properties of PLA2 from Bothrops brazili venom by rosmarinic (RSM) and chlorogenic (CHL) acids was analyzed through experimental and computational approaches. Three temperatures were evaluated (25, 37 and 50°C). In the experimental section, enzymatic assays showed that RSM is a better inhibitor in all three temperatures. At 50°C, the inhibition efficiency decayed significantly for both acids. Docking studies revealed that both ligands bind to the hydrophobic channel of the protein dimer where the phospholipid binds in the catalytic process, interacting with several functional residues. In this context, RSM presents better interaction energies due to stronger interactions with chain B of the dimer. Molecular dynamics simulations showed that RSM can establish selective interactions with ARG112B of PLA2, which is located next to residues of the putative Membrane Disruption Site in PLA2-like structures. The affinity of RSM and CHL acids towards PLA2 is mainly driven by electrostatic interactions, especially salt bridge interactions established with residues ARG33B (for CHL) and ARG112B (RSM) and hydrogen bonds with residue ASP89A. The inability of CHL to establish a stable interaction with ARG112B was pointed as the reason for its lower inhibition efficiency. The lower protein conformational stability promoted by ligands at 37°C for CHL and at 50°C for RSM was indicated as the reason for the lower inhibition efficiency at these respective temperatures.

29
  • HELOISE OLIVEIRA MEDEIROS DE ARAUJO MOURA
  • Innovative methodologies in the concept of biorefinery for the analysis and derivatization of lignocellulose.

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • Enrique Rodríguez-Castellón
  • HECTOR CASIMIRO GOICOECHEA
  • LEILA MARIA AGUILERA CAMPOS
  • LUCIENE DA SILVA SANTOS
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • RENATA MENDONÇA ARAUJO
  • Data: Oct 16, 2023


  • Show Abstract
  • Lignocellulose biorefinery is considered an industry analogous to oil refinery, with the potential to meet the demand for renewable fuels, chemicals, and materials in the near future. However, compositional characterization processes of potential lignocellulosic sources, in addition to treatment and heterogeneous conversion of extracted cellulose are some of the main limitations for expanding the diversity of products that can be obtained with high efficiency in biorefineries. In this work, a series of innovative methodologies were developed with focus on optimizing the processes of this industry. A new composition characterization method via peak deconvolution of derivative thermogravimetry curves (DTG) was applied to in natura biomass and pulps from corn cob (CC) and sugarcane bagasse (SB), in comparison to the standard method, with high precision (standard deviation <1.58%) and accuracy (standard error <5.74x10-2, R2>0.9993 and F>750,926). In addition, the new method made it possible to assess the treatment efficiency and reactivity of cellulose. Then, the optimization of heterogeneous synthesis of carboxymethylcellulose (CMC), one of the most commercially important cellulose derivatives, was carried out from these residual celluloses by a D-Optimal experimental design with 28 experiments. Analysis of variance (ANOVA) and response surface methodology (RSM) results proved with high precision (F=67.27; p-value<0.0001; R2=0.928; standard deviation=7.0x10-4) that the residual celluloses extracted are promising to produce CMC under milder conditions in comparison to literature, yielding about 279% (w CMC/w cellulose) of water-soluble CMC. Finally, a zinc molten salt hydrate was used as a solvent and reaction system for one-pot carboxymethylation of cellulose in a homogeneous medium, in a novel, more efficient, and environmentally friendly process. Carboxymethylation was proven after just 30 min of reaction by solubility tests and spectroscopic analyses, as well as the complexation of Zn2+ by carboxylate groups. X-ray diffraction and microscopic results proved this is a nanomaterial (10-36 nm) organized in a crystalline cubic microstructure formed by the aggregation of nanoparticles. Thus, the nanoZnCMC is the first cellulose-based biocoordination polymer reported in the literature. This material has potential high-tech applications, thus opening up a new chapter for studies in the homogeneous synthesis of innovative materials from renewable sources.

30
  • KÉVILLE PEREIRA DE OLIVEIRA
  • Adsorption on cross-linked chitosan from binary and ternary solutions of anionic drugs

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • CARLOS MAURICIO RABELLO DE SANT`ANNA
  • FABRICIO GAVA MENEZES
  • JOSE LUIS CARDOZO FONSECA
  • TIAGO PINHEIRO BRAGA
  • ZILVAM MELO DOS SANTOS
  • Data: Dec 19, 2023


  • Show Abstract
  • The inappropriate release of pharmaceutical residues into different environmental matrices has become a major concern around the world, since drugs and their metabolites can cause adverse effects on ecosystems and human health. Because of this, several studies have been carried out with the aim of removing these emerging contaminants from the aquatic environment through remediation methods. Thus, this research aims to understand the thermodynamic aspects involved in the removal of the drugs sodium cromoglycate (CG) and diclofenac sodium (DF) in aqueous solution through the adsorption process using cross-linked chitosan. The cross-linked chitosan (QR) samples and the others that were subjected to the adsorption process were characterized by infrared absorption spectroscopy, X-ray diffraction, zeta potential, scanning electron microscopy and thermogravimetry techniques. Regarding the adsorption equilibrium analyzes in a binary system, they were carried out using four different temperatures (15, 25, 35 and 45°C) and in the ternary at 25°C. To estimate the parameters of the adsorption isotherms, the experimental data were fitted with the following adsorption isotherms: Langmuir, Freundlich, Sips, Redlich-Peterson and Frumkin. To this end, the drugs, separated or mixed in aqueous solution, were quantified through the development of calibration curves obtained from experimental data measured by the UV-Vis spectrophotometry method. The results revealed that in binary systems the thermodynamic parameters of adsorption at low concentrations of adsorbate indicated an exothermic nature for CG, while for DF it was endothermic. Furthermore, entropic factors played a very important role, especially for DF, with adsorption being more favorable for CG. At high concentrations, the situation is reversed, that is, DF adsorption becomes more favorable, being endothermic for both drugs. In relation to adsorption in ternary systems, at lower concentrations, CG adsorption is favored, mainly because it has a lower Gibbs adsorption free energy. At a certain critical concentration, the adsorption changes drastically, in the form of a clear discontinuity in the adsorption isotherm, after this discontinuity, at higher concentrations, the adsorption is favored for the DF, due to the attractive interaction of the lateral parameters. Finally, it was shown that drugs adsorb spontaneously on the QR surface, being another alternative particle that can be applied in the treatment of effluents that contain pharmacological residues.

31
  • VALDIVINO FRANCISCO DOS SANTOS BORGES
  • Adsorption of surfactants in reservoir rocks via micellar solution: evaluation of experimental design and implementation of parameters

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • JOSE LUIS CARDOZO FONSECA
  • MICHELLE SINARA GREGÓRIO DANTAS
  • MONICA RODRIGUES DE OLIVEIRA
  • TIAGO PINHEIRO BRAGA
  • VANESSA CRISTINA SANTANNA
  • Data: Dec 22, 2023


  • Show Abstract
  • The adsorption of surfactants on rock surfaces can alter their hydrophobicity, surface charge, and other important properties that govern enhanced oil recovery (EOR) processes, such as reducing the interfacial tension between water and oil and increasing permeability. In general, the need to control and/or reduce the adsorption of surfactants on reservoir rock surfaces has been a challenging task in enhanced oil recovery (EOR) methods, as it directly impacts the project's economy. This requires a comprehensive study and understanding of the adsorption mechanism on rocks. The primary functions of this method are to reduce the water/oil interfacial tension and alter the wettability of the reservoir rock, which is often oil-wet, making it water-wet. This property of surfactants is due to their amphiphilic nature. In this study, the adsorption behavior via micellar solutions of ionic surfactants (OCS, OCBS, OMS, and SDS) and non-ionic surfactants (NP 9.5EO, NP 11EO, and NP 15EO) on carbonate and sandstone rocks was investigated. The finite bath method was employed to assess adsorption in all systems. For the anionic surfactants, a factorial experimental design was applied to optimize the adsorption process. It was observed that the adsorption of OCS, OCBS, and OMS was effective in limestone and negligible in sandstone, while SDS showed low adsorption efficiency in both rocks. The adsorption efficiency in limestone was 85.74%, 82.52%, and 45.30% for OCS, OCBS, and OMS, respectively. The isotherm data were well described by the Sips isotherm model for the surfactants OCS, OCBS, and OMS. The results indicated that the adsorption fitted well with the pseudo-second-order kinetic model. The Langmuir model simulated the adsorption isotherms of OCS better than the Freundlich model at three different temperatures of 298, 313, and 333 K. Thermodynamic parameters (ΔH, ΔS, and ΔG) indicated that the OCS adsorption process was spontaneous and endothermic. The experiments involving non-ionic surfactants were conducted according to the Scheffé network and showed an adsorption efficiency of 66.89% for NP-15EO, 67.15% for NP-11EO, and 70.60% for NP-9.5EO. Point F was chosen as the ideal point since it remained constant during the experiments, besides being a water-rich region and having low butanol content. The sandstone exhibited oil-favorable wettability, which underwent wettability inversion after treatment. Among the studied models, the Redlich-Peterson isotherm model was the best fit, indicating that the adsorption process occurs in monolayers and multilayers. The adsorbents were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermal Analysis (TG/DTG), X-Ray Diffraction (XRD), X-ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), Particle Size Analysis, and Zeta Potential Analysis.

2022
Dissertations
1
  • ANA KAROLINE SILVA DE AQUINO VITAL
  • “Dereplication of the hydro-ethanolic extract of the roots of Harpalyce brasiliana BENTH (Leguminosae) and evaluation of anti-inflammatory and antioxidant potential”

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • IAN CASTRO GAMBOA
  • RENATA MENDONÇA ARAUJO
  • YANNA CAROLINA FERREIRA TELES
  • Data: Jan 25, 2022


  • Show Abstract
  • The exacerbated production of reactive oxygen species in the body promotes an imbalance between the amount of oxidizing agents and the removal power of these species in the biological system, generating what is called oxidative stress. Several inflammatory diseases are associated with the overproduction of these species. The hydro-ethanolic extract of Harpalyce brasiliana Benth is widely used by the population in the treatment of snake bites and inflammatory disorders, and this effect is probably associated with the flavonoids present in this species, which are molecules already reported in the literature for their antiophidic properties. Dereplication studies began to be carried out with the aim of avoiding the re-isolation of already known compounds; however, it has become a very useful tool for analyzing the chemical profile of a species of interest. The dereplication of the hydro-ethanolic extract of H. brasiliana, a plant endemic to the Caatinga, popularly known as “snake root”, allowed the identification of 20 compounds by UPLC-MS/MS, mainly prenylated and geranylated flavanones and isoflavones. The extract was also investigated for its biocompatibility, as well as its antioxidant and anti-inflammatory effects. In cell culture, the extract has been shown to be safe in normal cell lines (RAW 247.6 and 3T3) at concentrations of 31-2000 µg/mL. The antioxidant activity of the extract (125-2000 µg/mL) was investigated through assays of reduction of diphenylpicryl-hydrazine, total antioxidant capacity, reducing power, hydroxyl radical elimination and chelation of iron and copper ions. In all in vitro antioxidant tests, the extract showed promising effects. For the dosage of NO (nitric oxide) in cell cultures (RAW 247.6), the extract (500 and 2000 µg/mL) showed a reduction in the expression of NO. In the zymosam-induced air pouch model, mice received zymosam (1 mg/mL) subcutaneously and were subsequently treated (100, 200, and 400 mg/kg) by gavage. In this animal model, the anti-inflammatory effect was observed by reducing the number of leukocytes (especially polymorphonuclear), myeloperoxidase production, total proteins and cytokine levels, as well as demonstrating the antioxidant effect by decreasing malonaldehyde and increasing parameters of glutathione. This approach demonstrates for the first time that the hydro-ethanolic extract from the roots of H. brasiliana is biocompatible, has antioxidant and anti-inflammatory properties in pre-clinical analyses, corroborating its use in folk medicine. Such data draw attention to the species as a promising source of bioactive molecules that can be used in the treatment of inflammatory diseases, which may contribute to the advancement of biopharmaceutical applications for this species.

2
  • CAIO VITOR CARVALHO DE SOUZA
  • THERMOCATALYTIC DEGRADATION OF POLYPROPYLENE RESIDUE USING MESO-MACROPOROUS BIMODAL SILICA AND H-Y ZEOLITE COMMERCIAL CATALYST.

  • Advisor : ANTONIO SOUZA DE ARAUJO
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ANTONIO SOUZA DE ARAUJO
  • EDJANE FABIULA BURITI DA SILVA
  • JOAO PAULO DA COSTA EVANGELISTA
  • Data: Jan 31, 2022


  • Show Abstract
  • Polymeric materials, especially plastic materials, due to their characteristics and properties, are widely used in the most diverse industrial sectors. The 20th century saw an exponential increase not only in production, but in the most diverse applications, from decoration tools to the automobile industry and medical hospitals. However, the excessive use of these materials, especially articles with a short lifespan, that is, those that are quickly discarded, has entailed a major problem, their inadequate disposal. Among the forms of disposal of these materials, none of them has the objective of recovering the energy content of this material, among the processes for adapting these plastic wastes, the only sustainable solution is the chemical recycling of this type of waste. Thermal or thermocatalytic degradation presents itself as a route for this purpose, with the possibility of transforming a residue into products with high added value in the fuel fraction, for example. For this purpose, the use of catalysts is necessary to improve processes, reducing their activation energy, reaction temperature and providing, from the catalyst used, routes for preferential products. Currently, zeolites are widely studied and used in various processes, especially in the petrochemical industry, but these materials have low transport rates of bulky molecules due to the small size of the micropores, so new studies are being carried out to synthesize new materials hierarchical, that is, with pore size greater than that of nanometric zeolites in order to reduce steric limitations for the conversion of bulky molecules. Thus, the bimodal catalyst, with pore size in the meso and macro order, previously synthesized was studied for polypropylene waste degradation and its catalytic activity was compared with commercial zeolite HY from the mass transformation of PP waste loads in a vessel reactor open and on a thermoanalytical balance. From the calculations of the kinetic parameters as well as the activation energy were performed using the Arrhenius equation and the Ozawa-Flynn-Wall method for isothermal and non-isothermal processes respectively. Thus, it was possible to evaluate the catalytic activity of the materials proposed for this work.

3
  • LALYSON MATHEUS LEMOS RODRIGUES DE SOUZA
  •  New phenantroline complexes of copper and cobalt with monastrol derivatives: synthesis, spectroscopic and electrochemical study.

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • CARLOS ROBERTO OLIVEIRA SOUTO
  • DANIEL DE LIMA PONTES
  • JOSÉ CLAYSTON MELO PEREIRA
  • Data: Feb 4, 2022


  • Show Abstract
  • Cobalt and copper complexes stand out as promising systems in the treatment of cancer, both due to the low toxicity of these metals in the biological environment, as well as the magnetic and electrochemical properties, making it quite interesting from the biological and medicinal point of view. In addition to metals, there is also a search for systems with bioactive ligands, for example monastrol derivatives, which can together with metal form structures with properties highly relevant for a pharmacoligal point of view. Thus, this work is presented, with the aim of contributing to the inorganic chemistry of Co(II) and Cu (II) systems, with the synthesis and spectroscopic and electrochemical characterization of new complexes with monastrol derivatives in systems [M(phen)(S-Cros)2] and [M(phen)(O-Cros)2], where  M = Co(II) e Cu(II), phen corresponds to 1,10-fenantrolina, S-Cros = ethyl 4-(4-hydroxy-3-methoxyphenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate, and O-Cros = ethyl 4-(4-hydroxy-3-methoxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate. All complexes were synthesized by adding to the precursor complexes [Co(phen)Cl2] and [Cu(phen)Cl2] the ligands S-Cros and O-Cros, in the ratio of 1:2 from precursor to ligand, using water as solvent, adjusting the pH to 11. The ligands were initially characterized by NMR 1H spectroscopy in DMSO-d6, presenting good correlation between the chemical shifts and the hydrogens in the molecules of S-Cros and O-Cros. Analyzing the vibrational spectra obtained in KBr pellets on the [M(phen)(S-Cros)2] and [M(phen)(O-Cros)2] systems, phenantroline bands in the complexes displays near the region of 1427, 854 and 723 cm-1 attributed to the stretching modes C-N and δ C-H, in addition to the S-Cros ligand bands, with stretching modes at 1692 (C=O), 1202 (C=S), 1029 (C-O ether) and 751 cm-1 ( C=S) and vibrational modes of the O-Cros  at 1696 (C=O ester), 1642 (C=O amide), 1226 (C-O) e 1023 cm-1 (O-CH3). The electronic spectra of the complexes [M(phen)(S-Cros)2] and [M(phen)(O-Cros)2] obtained in metanol, presented intraligand and intrametal bands, where in the ultraviolet region there are the bands of phenanthroline ligand, already the ligand S-Cros display a band at 304 nm, and the ligand O-Cros display a band at 285 nm. Additionally to these transitions, all complexes presented three d-d bands, because of the coordination environment of the complexes. Cyclic voltamograms of all complexes were obtained in TBAP dissolved in DMSO, presenting quasi reversible processes for both metals, for cobalt the processes are Co2+/Co1+ and Co3+/Co2+ and for Cu2+/Cu1+ for copper in the systems [M(phen)(S-Cros)2] and [M(phen)(O-Cros)2], besides there are oxireduction processes of the S-Cros and O-Cros ligands.

4
  • ALINE NASCIMENTO VASCONCELOS
  • DIMERS FATTY ACIDS AND FATTY AMIDES: PERFORMANCE IN THE STABILIZATION OF SYNTHETIC-BASED DRILLING FLUIDS

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • ROSANGELA DE CARVALHO BALABAN
  • ROSANGELA REGIA LIMA VIDAL
  • Data: Feb 18, 2022


  • Show Abstract
  • The performance of drilling fluids in the deepwater enviroments is negatively impacted by the formation of progressive gels. The stability of synthetic-base drilling fluids in offshore deepwater drilling has been acquired by the development of chemical additives that promote the maintenance of rheological properties, even with variations in temperature (flat rheological profile). Thus, fatty amides were synthesized from the condensation reactions between dimer acid and three different amines, separately: Diethanolamine (DEA), Poly(propylene glycol) bis(2-aminopropyl ether) (BPGA440) and Trimethylolpropane tris[poly(propylene glycol), amine terminated] ether (TPGA440) in the presence of N,N'-dicyclohexylcarbodiimide as coupling agent and 4-dimethylaminopyridine as catalyst, at 25°C. The products obtained were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (13C NMR). The results confirmed the amidation reaction between the reagents from the observation of the characteristic signal of the carbonyl group of amides in the FTIR and 13C NMR spectra. The solubility of dimer fatty acid and fatty amides was verified in water, olefin and brine saturated. In water DFA+DEA showed affinity with the aqueous medium, while DFA, DFA+BPGA400 and DFA+TPGA440 showed affinity with the non-polar medium because of the poor hydrophilicity. In addition, surface tension measurements verified that despite the amphiphilic structure of DFA and fatty amides, they do not have surface-active properties. To evaluate of DFA and fatty amides in synthetic-base drilling fluid, electrical stability tests, HTHP filtration and viscosity curves were performed at ambient pressure (~1 bar) and at pressure of 344 bar. At ambient pressure, the fluid with commercial rheological modifier (BDF-TM 990) presented variations in viscosity with the reduction of temperature, while the fluids prepared with DFA and fatty amides exhibited flat rheological profile. However, stable emulsions and rheological profile independent of temperature and pressure variations were obtained using the saturated dimer fatty acid.

5
  • BEATRIZ AZEVEDO GALVÃO DE LIMA
  • Development of phenanthroline complexes of manganese, cobalt and zinc with kojic acid: synthesis, spectroscopic and electrochemical study

  • Advisor : POLLYANA SOUZA CASTRO
  • COMMITTEE MEMBERS :
  • ANDERSON DOS REIS ALBUQUERQUE
  • DANIEL DE LIMA PONTES
  • EDUARDO HENRIQUE SILVA DE SOUSA
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • POLLYANA SOUZA CASTRO
  • Data: Mar 18, 2022


  • Show Abstract
  • The use of metals in pharmaceutical formulations in the treatment and diagnosis of diseases is something old, however, it was from the discovery of the antitumor properties of cisplatin that the eyes of the scientific community were opened to the application of metal complexes as chemotherapeutics in the treatment of cancer. The later discovery of the toxicity of cisplatin implied the search for new coordination compounds, aiming at similar efficacy allied to a low toxicity. In this context, manganese, cobalt and zinc complexes stand out in the literature as promising in the treatment of cancer, both for their low toxicity and for their magnetic and electrochemical properties. Therefore, this work presents, with the objective of contributing to the inorganic chemistry of Mn (II), Co (II) and Zn (II) systems, the synthesis and spectroscopic and electrochemical characterization of new complexes with phenanthroline and kojic acid of the type [M(phen)(koj)2], where M = Mn (II), Co(II) and Zn(II), phen corresponds to 1,10-phenanthroline and Hkoj to 5-hydroxy-2- (hydroxymethyl)-4H-pyran-4-one (kojic acid). All complexes were synthesized by adding the ligand Hkoj to the precursor complexes [M(phen)Cl2], with M = Mn (II), Co (II) and Zn (II), in a 1:2 ratio of precursor to ligand, using water as a solvent in the presence of potassium hydroxide. The compounds were characterized by vibrational spectroscopy in the infrared region (IR), electron absorption spectroscopy in the UV and visible region (UV-Vis) and cyclic voltammetry (CV). Analyzing the vibrational spectra obtained in KBr pellets, in the systems [M(phen)(koj)2] there is the presence of phenanthroline bands in the complexes near the region 1427, 844 and 727 cm-1, in addition to the ligand bands kojic acid, with stretch values at 1630, 1611, 1581, 877 and 548 cm-1. The electronic spectra of the [M(phen)(koj)2] complexes obtained in aqueous media showed intraligand bands in the ultraviolet region, which refer to electronic transitions of phenanthroline with absorption at approximately 222, 268 and 291 nm, in addition to the band around 320 nm referring to the kojic ion (koj-). While d-d bands were observed only for the Co and Mn (II) complexes. Cyclic voltammograms of Hkoj and the final complexes of Co and Mn (II) were obtained in KCl 0.1 mol.L-1, pH= 7.0, showing almost reversible processes for both metals. For cobalt there is the Co3+/Co2+ process and for manganese Mn3+/Mn2+, in addition to the irreversible oxidation process of the Hkoj ligand.

6
  • JOICY RIBEIRO DOS SANTOS
  • Optimization of biosorption process through factorial design for removal of Pb2+  metal ions from aquatic systems using mandacaru in natura

  • Advisor : POLLYANA SOUZA CASTRO
  • COMMITTEE MEMBERS :
  • ANDRÉ HENRIQUE BARBOSA DE OLIVEIRA
  • LUCIENE DA SILVA SANTOS
  • POLLYANA SOUZA CASTRO
  • RENATA MENDONÇA ARAUJO
  • Data: May 3, 2022


  • Show Abstract
  • The search for sustainable solutions for decontamination of water by heavy metals is a topic of absolute relevance for the future of humanity, given the ability of humans and the industrial processes developed by them to pollute the environment and consequently change the natural cycle of life. In this context, studying the natural products in order to develop new methodologies of remediation, which are low cost, efficient, easy to apply and that bring fast results is a way to mitigate these environmental damages. Therefore, this research work sought to develop a cheap and accessible biosorbent for the removal of metal ions using a native plant species of the caatinga, Cereus jamacaru, popularly known as mandacaru. The mandacaru stems were divided in three regions denominated pulp without cover (PW/OP), pulp with cover (PWP) and core (C) and used in natura. It was performed the chemical characterization of the regions by Fourier transform infrared spectrometry (FTIR) and quantification of total carbohydrates, soluble proteins and phenolic compounds in the aqueous extract. After the preliminary test of biosorption, a factorial design was applied with the objective to evaluate and optimize the effect of the variables that affect the biosorption process (pH, contact time, mandacaru region and ionic strength). Using the ANOVA tool, the statistical model that best fitted the data was the statistically significant and predictive model with the correlation coefficient of R2 of 0.9031, R-adj of 0.8243 and p < 0.05, with pH 5 solution, no NaCl addition, total time of 4h and PWP region. A remediation simulation was applied on control sample and real effluent samples of stream and sea water using the metal ion Pb2+. The removal of this contaminant was 97.3, 100 and 59.9%, for stream water, control water and sea water, respectively. The adjustment to the pseudo-second order kinetic model suggests chemisorption as the determining process for biosorption. Thus, we can conclude that the mandacaru regions demonstrated potential capacity to remediate water contaminated with this metal ion, opening new possibilities for applications of this bioadsorbent material in in real scenarios of environmental contamination.

7
  • JOHNATAN DE OLIVEIRA SOARES
  • SYNTHESIS, CHARACTERIZATION AND PHOTOCATALYTIC ACTIVITY OF OXIDES BASED ON CoFe2O4/Fe2O3 dispersed in KIT-6

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • TIAGO PINHEIRO BRAGA
  • POLLYANA SOUZA CASTRO
  • ANA PAULA DE MELO ALVES
  • Data: May 18, 2022


  • Show Abstract
  • Some poisonous compounds are resistant to degradation by common effluent treatments. For this reason, development of new methods and materials capable of solving this problem. Thus, the present work aimed to synthesize and characterize the solid CoFe2O4/Fe2O3-KIT-6, and to evaluate its performance in the photocatalytic degradation of Phenol and ultra RGB red remazol dye.The material obtained was characterized by X-ray Diffraction (XRD), Mössbauer Spectroscopy, X-ray Fluorescence (FRX), Infrared with adsorption of pyridine and NO (FTIR), Raman spectroscopy, Thermogravimetric analysis (TGA), adsorption/desorption of N2, Temperature Programmed Reduction (TPR-H2), Temperature Programmed Desorption (TPD-CO2), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Diffuse Reflectance Spectroscopy (DRS). From the XRD, N2, Raman, TG and Mössbauer fission analyses, it was possible to identify that the desired CoFe2O4/Fe2O3 phase was obtained supported on KIT-6, which maintained its structural properties. The bands at 1450, 1490 and 1609 cm-1 in the FTIR-pyridine and the FTIR-NO profile indicate the presence of Lewis acidic sites, while the TPD-CO2 profile showed a large amount of weak basic sites. The TPR-H2 result shows a reduction profile with significant events around 450°C and 850°C referring to the reduction of Fe and Co. The SEM and TEM images confirm that the morphology of the support was not significantly altered after metal impregnation. The band-gap energy of 1.7 eV indicates that the compound can be applied in photocatalytic degradation under UV/visible light, with the possibility of magnetic separation at the end of the reaction. The photocatalysis results indicate low degradation of phenol under the applied conditions and complete degradation of the remazol red ultra RGB dye in 1 hour of reaction. The combination of the proposed photocatalyst with the anatase phase (TiO2) shows significant improvements in the degradation process even in the absence of H2O2.

8
  • MARIA DO SOCORRO BEZERRA DA SILVA
  • Nickel catalyzed reductive decarboxylation to production drop-in biofuels.

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ARUZZA MABEL DE MORAIS ARAUJO
  • DJALMA RIBEIRO DA SILVA
  • LIVIA NUNES CAVALCANTI
  • REGINEIDE DE OLIVEIRA LIMA
  • Data: May 27, 2022


  • Show Abstract
  • Drop-in biofuels emerge as alternatives to petroleum derivatives to reduce CO2 emissions into the atmosphere, contributing to the energy transition to a low carbon economy. These fuels are composed of mixture of renewable hydrocarbons that ca be obtained from deoxygenation of biomass. Currently, hydrotreatment is main process applied for this purpose, however, the use of high temperatures and consumption of hydrogen gas is desirable look for other methods. For this, the present work proposed to develop a new methodology for deoxygenation of fatty acids, under mild conditions, using nickel complex as catalyst and low-cost silane as alternative source of hydrogen. Therefore, the fatty acids were converted into redox-active esters and optimization study was carried out, allowed decarboxylation of compounds at 40°C, without inert atmosphere or specific reactors. The results obtained by GC FID indicated that method promoted formation of hydrocarbons in range of green diesel and aviation biokerosene with high selectivity and yields 33-67%, under free-hydrogen conditions.

9
  • JHUDSON GUILHERME LEANDRO DE ARAUJO
  • SYNTHESIS OF DROP-IN BIOFUELS VIA PHOTOCATALYTIC DECABOXYLATION.

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ARUZZA MABEL DE MORAIS ARAUJO
  • DJALMA RIBEIRO DA SILVA
  • EDJANE FABIULA BURITI DA SILVA
  • LIVIA NUNES CAVALCANTI
  • Data: May 27, 2022


  • Show Abstract
  • The environmental impacts generated by the emission of CO2 and the energy insecurity of fossil fuels have attracted the attention of governments and transport sectors around the world. In this context, the replacement of petroleum derivatives by drop-in biofuels appears as an alternative for mitigating greenhouse gases (GHG) and diversifying the energy matrix. In Brazil, with the creation of the fuels of the future program, the development and incorporation of these biofuels is projected, and investments in R, D&I have been carried out with the objective of diversifying the biomass used and their conversion methods, which are currently expensive because they require harsh operating conditions and use non-renewable hydrogen gas. Therefore, the development of a synthetic route for converting new biomasses into drop-in biofuels using mild and H2-free conditions is desirable. Thus, in this work two photocatalytic systems were developed for the deoxygenation of fatty acids, which made it possible to obtain biohydrocarbons using organic catalysts under conditions of ambient temperature and pressure, free of metals and hydrogen gas. After optimization, the protocols were able to convert fatty acids into Cn-1 hydrocarbons with high selectivity, including a conversion of 97% of the acids obtained from licuri oil to produce a mixture of C11-C17, which is compatible with the range of the biojet and green diesel.

10
  • JOSUÉ DA CRUZ DE SOUZA
  • Development of hierarchical zeolites of different dimensions with potential for bulk hydrocarbon processing.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • FABIO GARCIA PENHA
  • MARIELE IARA SOARES DE MELLO
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: May 27, 2022


  • Show Abstract
  • The evaluation of the influence of secondary porosity, the dimensionality of zeolitic structures with 1D, 2D and 3D pore systems exert on the accessibility of voluminous hydrocarbons to active sites were evaluated in the present work. Y, ZSM-5 and mordenite zeolites underwent different top-down treatments to introduce secondary porosity. The analysis of X-ray diffraction (XRD), X-ray fluorescence (FRX), Fourier Transform infrared spectroscopy (FTIR), infrared spectroscopy of pyridine adsorption and desorption (IR-Pyridine), textural analysis by adsorption and nitrogen desorption, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) confirm the changes. The zeolites Y and ZSM-5 had a high increase in the specific area, reaching values of 858 m2/g with the maintenance of the volume of intrinsic micropores, as well as the increase in the concentration of Brönsted acid sites, reaching values of 625.4 and 892 .7, respectively. The mordenite zeolite showed an increase in the volume of mesopores and high retention values, and subsistence of Brönsted acidity. The materials were applied in the cumene cracking reaction and evaluated against the catalytic accessibility and influence of acidity. The synthesized zeolites Y, ZSM-5 and mordenite proved to be efficient catalysts, reaching values of 100% cumene conversion practically throughout the reaction time. The hierarchy factor (FH) is used to study the influence of the implemented secondary porous network, as well as its hierarchical structural organization.

11
  • JÚLIA CAROLINE CELESTE VIANA BENTO
  • ELECTRO-DECARBOXYLATION OF FATTY ACIDS TOWARD BIOFUELS.

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ARUZZA MABEL DE MORAIS ARAUJO
  • DJALMA RIBEIRO DA SILVA
  • JOAO PAULO DA COSTA EVANGELISTA
  • LIVIA NUNES CAVALCANTI
  • Data: Jun 15, 2022


  • Show Abstract
  • Electrochemical processes are promising alternative routes to promote cleaner, safer, and more sustainable redox transformations. The decarboxylative upgrading of biogenic acids via (non-)Kolbe electrolysis has demonstrated a high potential to produce valuable compounds for the chemical and fuel industries. Notably, bio-derived hydrocarbons and oxygenates have shown adequate properties that enable their use as fuel additives associated with reduced levels of emissions. Therefore, the research reported herein aimed to develop an electrocatalytic method to decarboxylate C12:C18:1 fatty acids which are predominant in the composition of liquid biofuel feedstocks. The reaction products were analyzed by CG/MS, FTIR, and TG/DTG techniques. In the absence of metal based catalysts, additives, or redox reagents, the electrochemical system enabled the quantitative conversion (97-100%) of pure fatty acids, as well as mixtures, including the one produced through Licuri oil hydrolysis, to afford mixtures composed by 19-36% of C11-C17 olefins at room temperature and pressure, employing graphite electrodes. The electrodecarboxylative protocol demonstrated the potential to serve as an alternative to hydrogen based thermocatalytic reactions to produce renewable hydrocarbons under exceptionally mild reaction conditions.

12
  • KATHERINE LIMA BRUNO
  • Spectroscopic and electrochemical study of new mono and binuclear complexes of Cu(II) and Fe(II) with nitrogenous ligands.

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • DANIEL DE LIMA PONTES
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • WENDY MARINA TOSCANO QUEIROZ DE MEDEIROS
  • Data: Jul 26, 2022


  • Show Abstract
  • In an attempt to develop more efficient compounds for pharmacological treatments, bioinorganic chemistry has been playing important roles with the participation of coordination compounds. Among these, copper(II) and iron(II) complexes stand out, which play important roles in biological systems, naturally – as in enzymes and proteins – or artificially – as pharmacological agents. Using these metals associated with molecules that already have biological activity described in the literature, such as phenanthroline, piperazine and nitrite, it becomes possible to develop drugs with greater potential, due not only to the diverse structural possibility, but to the wide spectrum of biochemical applications. . In this sense, this work aims to contribute to bioinorganic chemistry with the synthesis and characterization of new mono compounds - [Cu(phen)(pip)NO2]Cl and Na2[Fe(CN)4(NH3)2] - and binuclear – Na[(NO2)(phen)Cu–pip–Fe(CN)4(NH3)] – of copper(II) and iron(II), where phen = 1,10- phenanthroline and pip = piperazine. The mononuclear copper complex was obtained through the reaction, in methanol, between its precursor – [Cu(phen)Cl2] – and the ligands piperazine and nitrite; the iron compound, in water, through the reaction between its precursor – Na2[Fe(CN)4(DMSO)2] – and ammonia gas, with subsequent precipitation (NaI); and the binuclear, from the addition of the two monomers in methanol and water, all of which are characterized by spectroscopic (IV and UV-Vis) and electrochemical (cyclic voltammetry) techniques. By means of IV and Uv-vis, it was possible to verify the main vibrational modes of phenanthroline and piperazine in the synthesized copper systems, through the C=C (1580, 1517, 1492 and 1427 cm-1) stretching of the rings and N-H (1615 cm-1) of the amine, as well as intense bands with transitions π→π* (204, 221, 272 and 293 nm) and n→π* (204 nm) in the ultraviolet region, respectively, in addition to the d-d bands (625 and 692 nm) of Cu2+  in the visible region. The nitrite stretches were also evidenced in the IR with the signs at 1349(a) and 1269(s) cm-1. For iron systems, it was possible to identify their main stretches (νN-H, νC≡N, δFe-CN), through the IV, and their bands in the UV-vis, such as the MLCT charge transfer (dπ Fe2+ → pπ * CN- at 221 nm) and d-d (405 and 518 nm) of Fe2+. The cyclic voltammograms allowed the visualization of a quasi-reversible system for the 3 complexes, with only one redox process each, referring to the pair Cu2+/1+ and Fe2+/1+ and the overlap of these two in the binuclear, in addition to the observation of greater stability and evaluation of the nature of the ligands.

13
  • MÁGNO KLEBSON AUGUSTINHO SENA
  • Synthesis, spectroscopic and electrochemical characterization of new cobalt (III) complexes with nitrogenous ligands.

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • ANDERSON DOS REIS ALBUQUERQUE
  • DANIEL DE LIMA PONTES
  • WENDY MARINA TOSCANO QUEIROZ DE MEDEIROS
  • Data: Jul 29, 2022


  • Show Abstract
  • Tumor hypoxia regions are currently one of the main therapeutic targets for anticancer therapy, because these regions are related to the increase of mortality and metastasis, therefore, today in bioinorganic research seeks to develop metal complexes that can act as hypoxia-activated pro-drugs (HAPs). Cobalt (III) complexes are widely studied as HAPs because they are inert, and then when reduced to Co (II) present a lability (reactivity) and release a drug into the tumor environment. In this context, the present work aims to synthesize new cobalt complexes with the auxiliary ligand o- phenanthroline (phen), and the ligands imidazole (imd), 4-aminopriridin (4apy) and 7-hydroxy-4-imidazolylmethylcoumarin (S1) as pro-drugs. Thus, cis-[Co(phen)2L2]n+ complexes were synthesized, l being the ligands Cl-, imd, 4apy and S1, and n equal to 1+ or 3+. The S1 ligand was synthesized from a methodology reported in the literature and characterized by spectroscopic techniques (UV-vis, fluorescence, IR, NMR), while the synthesized complexes were characterized by spectroscopic and electrochemical techniques.   From the vibrational and NMR spectra, it was possible to confirm the structure of the S1 ligand, it is through the data of absorption and fluorescence to identify pKa of approximately 7.5 for the ligand, besides the fluorescence having a strong dependence on pH and solvent. The IR spectra for the complexes confirmed the coordination of the ligands by presenting characteristic stretches from phen (C=N), imd (N-H), 4apy (N-H) and S1 (C=O). The electronic spectra in DMSO presented intraligands bands in the region from 200 to 400 nm and the d-d transitions in 534 and 612, 487, 462 and 530, 475 nm for the cis-[Co(phen)2L2]n+ complexes with L =chlorides, imd, S1 and 4apy, respectively. In addition, it was observed the order Cl-< S1 < imd < 4apy for the crystal field splitting. From the fluorescence of the complex containing the S1 ligand, it was possible to observe an emission band at about 472 nm. Additionally, the cyclic voltammograms of the cis-[Co(phen)2L2]n+ complexes presented  two redox pairs for the metal, CoIII/II and CoII/I, with potentials of E1/2  between 380 and 460 mV for CoIII/II and -860 to -750 mV for CoII/I, presenting redox process within the biological medium range for generation of reactive oxygen species.

14
  • RITA DE CÁSSIA NASCIMENTO SOUSA
  • Biomimetic Oxidative Reactions with Acanthoic Acid.

  • Advisor : LEANDRO DE SANTIS FERREIRA
  • COMMITTEE MEMBERS :
  • ELIANE DE OLIVEIRA SILVA
  • LEANDRO DE SANTIS FERREIRA
  • RENATA MENDONÇA ARAUJO
  • Data: Aug 30, 2022


  • Show Abstract
  • The  acanthoic  acid,  (-)-pimara-9(11),15-dien-19-oic  acid,  is  a  type  of  pimaradiene  diterpene  mainly isolated  from  the  Korean  medicinal  plant, Acanthopanax koreanum. Other species as Annona amazonica, Rollinia pittieri, Rollinia exsucca, Aralia racemosa and Croton oblongifolius Roxb also revealed this diterpene in its constitution. Despite its biological diversity for the treatment of several diseases described in the literature (ulcerative colitis, hepatic fibrosis, type 2 diabetes, inflammatory cardiovascular diseases and periodontal), studies related to its pharmacokinetic parameters such as absorption, metabolites characterization, elimination kinetics in addition to the toxicity related to its administration still need to be investigated. In this way, this study aims to investigate the phase I metabolism of acanthoic acid through biomimetic oxidative reactions with the Jacobsen catalyst, using PhIO, m-CPBA and H2O2  as oxygen donors in homogenous medium. The Jacobsen catalyst is known by its easy synthesis and purification, and along with the metalloporphyrins have the ability to simulate the catalytic activity of the cytochrome P450 enzymes, which are the main responsible by phase I metabolism. Through the analysis by GC-MS, it was possible to observe the ratio 1:60:120 (catalyst:substrate:oxidant) as the more efficient for the conversion of acanthoic acid for the formation of the possible products oxidized mainly in the system with PhIO. However, none products were detected when H2O2  was used as oxidant even in this proportion mentioned. At least six possible products of oxidation were detected which 4 of them can be considered isomers. In this way, the present work may serve as a basis for investigating the oxidation of acanthoic acid by other in vitro methodologies and assist in the characterization of products obtained in vivo. Hopefully, that will encourage future pharmacological and toxicological studies to ensure their safety.

15
  • TAINÁ MELQUÍADES ARROSPIDE
  • Prenylated and Geranylated Derivatives of Non-oxidized Monomeric Acylphloroglucinols of Natural Origin: A Review

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • JULIA MORAIS FERNANDES
  • LEANDRO DE SANTIS FERREIRA
  • RENATA MENDONÇA ARAUJO
  • Data: Sep 23, 2022


  • Show Abstract
  • Derivatives of acylated monomeric phloroglucinols are predominant secondary metabolites in the genus Hypericum and have an acyl group directly connected to the THB nucleus, in addition to very commonly also having prenyl and geranyl substituents. The origin of these compounds shows that the carbonyl unit is bioenergetically favored, this is because phloroglucinols come from a biosynthetic route where the THB nucleus is biosynthesized by the acetate-malonate pathway, being susceptible to cyclization and oxidation. Due to its structural variability and associated diverse biological activities, there is an interest in new studies and reviews that aim to explore the topic in a more specific way. For this review, a survey of data from the period between 1965 and 2022 was carried out on the platforms Google Scholar, CAPES Periodicals, Science Direct and ScienceFinder, considering as inclusion criteria compounds of the class of monomeric acylphloroglucinols, also called acetophenones, from the aforementioned biosynthesis , relating to the different species of plants where they were isolated from their extracts and cataloged structurally and biologically. Among the main biological activities found, the following stand out: anti-inflammatory, antibacterial and cytotoxic. 1H and 13C NMR (nuclear magnetic resonance) data served as a basis for the chemical analysis of the compounds and their grouping into classes of monocyclic and polycyclic monomers with prenyl and geranyl substitutions.

Thesis
1
  • JORGE LEANDRO AQUINO DE QUEIROZ
  • Development of miniaturized electrochemical sensors for monitoring species of environmental relevance.

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • POLLYANA SOUZA CASTRO
  • FABIANA DA SILVA FELIX
  • MARCO ANTONIO QUIROZ ALFARO
  • SUELY SOUZA LEAL DE CASTRO
  • Data: Jan 28, 2022


  • Show Abstract
  • Electrochemical advanced oxidation processes (EAOPs) are new and promising methodologies for wastewater treatment, at domestic or industrial level, that emerge as an alternative to traditional water treatment methods. On EAOPs reactors, a wide variety of organic or inorganic pollutants can be degraded by strong oxidizing agents electrochemically generated. Therefore, on these processes, it is crucial a proper monitoring for the generation of oxidants and the degradation of pollutants in order to make the process more efficient and reduce costs. Thus, in this work we propose the utilization of miniaturized electrochemical sensors for the real time monitoring of species generated or degraded in the reactor. First, an integrated Pt microelectrode (a microelectrode that combines a working Pt microdisc to a silver quasi-reference electrode) for monitoring hydrogen peroxide generated in the reactor. Using this integrated microelectrode it was possible to obtain a real-time profile for H2O2 generation by the electrolysis of a 0.10 mol L-1 HClO4 solution. The reactor was equipped with a Nb/BDD anode and a Ti cathode under different current densities (30, 60, 90 e 120 mA cm-2). The H2O2 generation rate was strongly dependent on the applied current density (j) and that it reaches its peak production after 90 minutes of electrolysis, exhibiting a pseudo zero-order kinetics. The results obtained were in accordance with a spectrophotometric method used as reference at a 95% level of confidence. In a second approach, a gold microelectrode set was obtained from discarded computer microchips. The set of microelectrodes was modified with electrochemically reduced graphene oxide and applied to quantify isoniazid antibiotic by linear scan voltammetry, showing a good linear correlation (R2 = 0.9926) and limit of detection (1.38 μmol L-1) on the concentration range from 5.0 to 100.0 μmol L-1. The sensor was then applied to isoniazid determination in river and lagoon water samples.

2
  • JOSÉ AURÉLIO PINHEIRO
  • THERMORESPONSIVE CELLULOSE NANOCRYSTALS: EVALUATION OF THE VERSATILITY OF USE THROUGH TESTS IN DRILLING FLUIDS AND RAW MACROPHAGE CELLS.

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ROSANGELA DE CARVALHO BALABAN
  • PAULO CÉSAR FRANÇA DA CÂMARA
  • HUGO ALEXANDRE DE OLIVEIRA ROCHA
  • ANA MARIA DA SILVA MAIA
  • LISZT YELTSIN COUTINHO MADRUGA
  • Data: Feb 4, 2022


  • Show Abstract
  • In this study, cellulose nanocrystals (CNC) were obtained from acid hydrolysis of a commercial cotton cellulose sample. Then, the CNCs were chemically modified by grafting chains of the thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAM). Grafting reaction was performed using the monomer N-isopropylacrylamide (NIPAM) using the redox pair potassium persulfate/N,N,N',N'-tetramethylethylenediamine as initiators at room temperature (~ 25 °C), or by thermal activation (60 °C) of potassium persulfate. The materials were characterized by elemental analysis, Fourier Transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-Ray diffraction (XRD) and thermogravimetric analysis (TGA). The properties of CNC and their thermorresponsive derivatives in aqueous medium were evaluated by dynamic light scattering (DLS), zeta potential and confocal microscopy. In addition, the visual stability of modified materials in solvents of different polarities was evaluated. CNC grafted with PNIPAM were studied as additives in synthetic-based drilling fluids. They were able to reduce the filtrate under high temperature and high pressure (HTHP) conditions, indicating a high potential for application in the area. Furthermore, in a second line of applicability, in the biomedical area, modified CNC and its precursors were evaluated for cytotoxicity, immunomodulation and ability to reduce cellular oxidative stress. They exhibited good cytotoxic and antioxidant activities on RAW macrophage cells, even greater than their precursors. The protection of cells against oxidative damage by CNC-g-PNIPAM opens the way for application in the biomedical field.

3
  • MARLIZIA ADJA LOPES DE OLIVEIRA
  • THERMORESPONSIVE NANOGELS BASED ON MANGO STARCH AND THEIR APPLICABILITY AS CARRIER OF HYDROPHOBIC MOLECULES

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ANA MARIA DA SILVA MAIA
  • JOSE LUIS CARDOZO FONSECA
  • KEILA DOS SANTOS ALVES
  • LISZT YELTSIN COUTINHO MADRUGA
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Feb 25, 2022


  • Show Abstract
  • The Northeast Brazilian produced 1,093,864 tonnes of mango in 2019. It is estimated that 40-60% of mango production is discarded as waste, in forms such as husks and pits. Almost 60% of the dry mass of mango kernel is due to starch. Given this scenario, producing copolymers based on mango starch, which is currently discarded as agro-industrial waste, in the form of thermoresponsive nanogels for drug incorporation is an economically viable solution. In addition, a problem faced in the pharmacological area is that most hydrophobic drugs have low absorption in the human body, due to their low solubility and stability in aqueous media. Consequently, the use of specific carriers for the delivery of hydrophobic drugs can increase their efficiency of action. Therefore, in this work the proposal is the production of biodegradable and thermoresponsive nanovehicles that are effective in the transport of hydrophobic drugs. For this, first, the starch was crosslinked with glutaraldehyde, followed by carboxymethylation with monocloacetic acid and, finally, by grafting of poly(N-isopropylacrylamide) chains (PNIPAM). The results obtained in the elemental analysis, hydrogen NMR and infrared with Fourier transform revealed the structural aspects and composition of the materials, evidencing the success in the production of carboxymethylamido-g-poly(N-isopropylacrylamide) (CMA-g-PNIPAM). Through SEM and DLS it was found that the nanoparticles showed high swelling power. The transmittance of the copolymers in aqueous media abruptly decreased above 33 °C. The nanogels showed no toxicity to human adipose tissue-derived stem cells (ADSCs) and red blood cells (RBCs). Likewise, the products proved to be non-hemolytic in the LDH, alamarBlue and hemolysis assays. In view of the results obtained, the potential of polymeric matrices based on CMA-g-PNIPAM as carriers of hydrophobic drugs was evaluated, using curcumin as a model drug. The curcumin incorporation kinetics data showed that in 8 hours the polymer matrix was able to absorb approximately 25% of the available free curcumin, fitting the pseudo-second order sorption model. Based on the results obtained, it is concluded that the synthesized copolymers present interesting functional characteristics for application in hydrophobic drug delivery systems.

4
  • JANNYELY MOREIRA NERI
  • FUNCTIONALIZED QUINOXALINE APPLIED TO THE SYNTHESIS OF SILVER NANOPARTICLES AND INCLUSION COMPLEX WITH β-CYCLODEXTRIN

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • JOSE LUIS CARDOZO FONSECA
  • ANA CAROLINA DE OLIVEIRA NEVES MENEZES
  • JOSIEL BARBOSA DOMINGOS
  • VANDERLEI GAGEIRO MACHADO
  • Data: Mar 21, 2022


  • Show Abstract
  • Quinoxalines, belonging to the class of nitrogenated heterocycles, have applications in biological and technological areas, in addition to versatility when it comes to organic synthesis. They are also present in chromogenic chemical sensors, which are defined as optical devices for detection of analytes of interest, whose development has been stimulated in recent decades because of the ease of use, low costs, and high selectivity and sensitivity, even in complex samples. Recently, the use of silver nanoparticles as chemosensors has brought new possibilities for the growth of this area. Metal cations and amino acids are important analytes explored in the development of selective synthetic probes, especially because of their roles in biological processes and environmental issues. The present work describes the synthesis of silver nanoparticles (AgNPs) functionalized with the derivative 2,3-diethanolaminoquinoxaline (DEQX) via a low environmental impact synthetic route. The QX-AgNPs system was characterized by spectroscopy in the ultraviolet-visible (UV-vis) and infrared (ATR-FTIR) region, as well as by transmission electron microscopy (MET), and then applied as a chromogenic probe for selective detection of L-cysteine, as well as Mg2+ and Sn2+ in aqueous solution. Qx-AgNPs were able to selectively detect cysteine and Mg2+ in alkaline medium among various amino acids and metal cations, respectively. On the other hand, QX-AgNPs were effective in detecting Sn2+ at pH 7.5. The selective detection of the analytes and the respective mechanisms were adequately discussed based on UV-vis, MET and ATR-FTIR analyses. The detection limits reached 2.7 nmol L-1, 15 nmoL L-1 and 18 nmoL L-1 for cysteine, Mg2+ and Sn2+, respectively. These limits were ratified as the success of quantification of cysteine in urine and Mg2+ in tap water by Qx-AgNPs. Moreover, in view of the low water solubility of DEQX and promising anticancer activity it has shown in recent works, the present work also reports the obtainment of inclusion complexes of DEQX with β-cyclodextrin (βCD) (DEQX/βCD), a useful excipient in a wide field of applications, obtained by physical mixing (PM) and kneading (KND) methods, with the aim of improving the physicochemical properties of said quinoxalin derivative. The DEQX/βCD complex was properly characterized by ATR-FTIR, nuclear magnetic resonance (NMR), X-ray diffractometry (XRD), scanning electron microscopy (SEM), as well as thermal analyses thermogravimetry (TG) and differential scanning calorimetry (DSC). Phase solubility indicated that the solubility of DEQX increased with increasing concentrations of βCD, that the DEQX/βCD complex is formed with 1:1 stoichiometry, and the inclusion trend of DEQX with βCD was adequate. In addition, the stable three-dimensional structure obtained with the molecular dynamics simulation method showed insertion of DEQX into the cavity of βCD. The obtained inclusion complexes were also evaluated against cytotoxic properties in human erythrocytes by hemolytic test, which showed that both DEQX and its inclusion complexes with βCD, obtained by PM and KND were found to be non-toxic. Therefore, the results obtained show the potential of DEQX for applications of extreme relevance, indicating an important contribution to the area of nanosensors for multiple detection of analytes in aqueous media, as well as for future advances in anticancer tests, after evidence of association with βCD.

5
  • ALDO MIRO DE MEDEIROS
  • CATALYTIC PYROLYSIS OF THE COCONUT OIL WITH  Ni/SBA-15 e Ni/H-Beta.

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • ANDRE ANDERSON COSTA PEREIRA
  • DJALMA RIBEIRO DA SILVA
  • ENIO RAFAEL DE MEDEIROS SANTOS
  • SAULO HENRIQUE GOMES DE AZEVÊDO
  • Data: Apr 29, 2022


  • Show Abstract
  • In the present work, a study of the pyrolysis process of coconut oil (Coco Nucifera), using the Ni catalyst on SBA-15 supports and on H-Beta zeolite, to produce aviation biokerosene was carried out. The catalysts were calcified and characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy coupled to the Energy Dispersive Spectrometer (SEM/EDS). The SBA-15 was obtained with hexagonal ordering and symmetry, the thermal activation of H-Beta did not compromise its structure and the impregnations with the metal resulted in the targeted percentages and its presence did not change the morphology and structure of the supports. The thermal and kinetic studies were performed using the Thermogravimetric Analysis technique (TGA/DTG). Then, Gas Chromatography coupled with Mass Spectrometry (GC/MS) was used to analyze the bio-oil samples. In order to better understand the behavior of this process, heating rates of 5, 15 and 20 °C/min were used in the experiments, in the temperature range between 30 and 600 °C and 10% of catalyst. In general, the increase in the heating rate provided an increase in the temperature range, maximum temperature and a decrease in mass loss. In the kinetic study, lower heating rates produced higher conversions and the Kissinger-Akahira-Sunose (KAS) model was better suited to the process. Conversions greater than 90% were verified. The catalyst with the highest catalytic activity was H-Beta 5% Ni for the entire process with an average Ea of 318.06 kJ/mol for the KAS model. The influence of nickel metal on the reaction was also analyzed using SBA-15 and H-Beta as catalytic supports. Samples were characterized by CG/MS. In thermal pyrolysis without Ni, bio-oil yields of 69.76% were achieved. Using the H-Beta 5% Ni catalyst, 77.83% of bio-oil and 1.80% of water were reached, showing that Ni provided a certain deoxygenation of the bio-oil. The catalysts SBA-15 1% Ni, SBA-15 5% Ni, H-Beta 1% Ni and H-Beta 5% Ni produced hydrocarbons in the range of C11-C16 kerosene at 73.73%, 73.17%, 78 .08% and 2.77%, respectively. Concluding that the first 3 were selective in the kerosene range.

6
  • MARFRAN CLAUDINO DOMINGOS DOS SANTOS
  • Infrared and molecular fluorescence spectroscopy in conjunction with analysis multivariate in the detection of arboviruses in Aedes aegypti mosquitoes and clinical samples.

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • KASSIO MICHELL GOMES DE LIMA
  • FABRICIO GAVA MENEZES
  • LUCIENE DA SILVA SANTOS
  • HECTOR CASIMIRO GOICOECHEA
  • ROBINSON SABINO DA SILVA
  • Data: Jul 26, 2022


  • Show Abstract
  • Viral diseases are among the main public health problems, especially arboviruses, which are among the viruses that most infect humans, with an estimated 3 billion people living in areas at risk of infection. The aim of this research was to evaluate the application of spectroscopic techniques in the detection of arboviruses in Aedes aegypti mosquitoes and clinical samples. In the described studies, on this thesis, molecular fluorescence spectroscopy was applied together with the multivariate analysis techniques PARAFAC-LDA, PARAFAC-QDA, and NPLS-DA, as a new sensitive, specific, fast, simple methodology capable of identifying spectral variations between clinical samples with and without dengue and chikungunya viruses. To get this, Excitation-Emission Matrix (EEM) of 26 samples for each class (healthy x dengue x chikungunya) were used, totaling 78 samples. The samples were divided into calibration and test sets and, after building the models, the results were analyzed based on calculations of accuracy, sensitivity, specificity, and F-score. It was observed that the most efficient model in the classification work was the PARAFAC-QDA, obtaining the maximum value for all the calculated figures. PARAFAC-LDA and NPLS-DA also achieved encouraging results. The loadings captured in PARAFAC were provided and can be used in future studies to prove the relationship (or not) of the spectral data with the presence of viruses. In another study, infrared spectra (NIR and MIR) were used together with the SPA and GA variable selection algorithms, to select wave numbers capable of discriminating female Aedes aegypti mosquitoes infected with dengue (n = 32) from uninfected mosquitoes (n = 66). For this, SPA-LDA and GA-LDA models were constructed for the two techniques (NIR and ATR-FTIR). The built models were evaluated based on sensitivity and specificity calculations, and it was observed that for both SPA-LDA and GA-LDA, the models based on NIR spectra obtained better classification values, reaching 82.65 % of sensitivity and specificity for NIR-SPA-LDA; and 100.00 % for sensitivity and specificity for NIR-GA-LDA. Finally, it was observed that EEM matrices have the potential to be used as screening or diagnosis of arboviruses, having advantages when compared to more conventional techniques, demonstrating that, in the future, it will be possible to rely on portable NIR instruments in the work of entomological surveillance and prediction of dengue outbreaks.

7
  • MARCELO VICTOR DOS SANTOS ALVES
  • DEVELOPMENT  OF  ANALYTICAL  METHODOLOGIES  BASED  ON  MASS  SPECTROMETRY  AND  MULTIVARIATE ANALYSIS IN THE DIAGNOSIS OF FIBROMYALGIA.

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • KASSIO MICHELL GOMES DE LIMA
  • LUCIENE DA SILVA SANTOS
  • RODRIGO PEGADO DE ABREU FREITAS
  • AMÉLIA PASQUAL MARQUES
  • BONIEK GONTIJO VAZ
  • Data: Aug 25, 2022


  • Show Abstract
  • This thesis presents the development of new analytical methodologies that combine instrumental mass spectrometry readings with multivariate classification, in the search for the differentiation of blood plasma samples for the detection of fibromyalgia. Within the execution of the research, the studies carried out in this thesis explored the Paper Spray Ionization Mass Spectrometry (PSI-MS) to obtain spectra from the blood plasma of patients with and without fibromyalgia, and the processing of these spectral data by multivariate analysis models. The multivariate classification techniques used represent Principal Component Analysis (PCA), Successive Projection Algorithm (SPA), Genetic Algorithm (GA), Linear Discriminant Analysis (LDA) and Quadratic (QDA) and Support Vector Machine (SVM) proposing PCA-LDA, SPA- LDA, GA-LDA, PCA-QDA, SPAQDA, GA-QDA, PCA-SVM, SPA-SVM and GA-SVM models. For a first study, using a total of twenty samples, the sensitivity and specificity results showed 100% separation between classes, involving the supervised SPA-LDA technique, in addition to good classifications with other models. For a second study the classifications obtained 100% sensitivity for the PCA-LDA model, with sixty four samples, using patients with symptoms related to catastrophizing pain (CAT) as a parameter. In addition to this last result, the second study also presented classifications of different datasets with samples of patients with and without fibromyalgia, related to other common symptoms in the disease. Another important result, present in both studies, is the association of variables selected by the classification models to the lysophosphatidylcholine (LysoPC) metabolite class, mentioned in studies on fibromyalgia biomarkers. Thus, the results demonstrated suggest the development of useful tools in the screening of fibromyalgia, with the advantages of providing quick results, of simple operation and use of small aliquots of blood plasma  samples,  also  providing  a  good  theoretical  contribution  on  the  diagnostic  approach  of  fibromyalgia,  demonstrating  the  good  execution  of  the  analytical methodology in the detection of the disease.

8
  • KEVERSON GOMES DE OLIVEIRA
  • Sustainable Biodiesel Production: Development of Green Catalysts, Transesterification of Residual Cooking Oil and Conversion of Glycerol to Triacetin.

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • LUCIENE DA SILVA SANTOS
  • POLLYANA SOUZA CASTRO
  • CARLOS AUGUSTO CABRAL KRAMER
  • ENRIQUE RODRÍGUEZ CASTELLÓN
  • LEILA MARIA AGUILERA CAMPOS
  • LEONARDO SENA GOMES TEIXEIRA
  • Data: Aug 26, 2022


  • Show Abstract
  • Due to environmental concerns, several researches emerge in the search for energy alternatives to the use of fossil fuels. Among the possibilities, there is biodiesel, which allows the reduction of the use of diesel, contributing to the mitigation of environmental impacts, as it is a natural and renewable source. This work proposed a greener and more sustainable process for the production of biodiesel from residual cooking oil (OCR), using catalysts from natural and/or residual sources, from the ash of banana peels (BPC) and tangerine (TPC), in addition to sodium and potassium silicates (SPS) originating from beach sand. At the end of the residue recovery cycle, acetins were synthesized from the residual glycerol produced in the transesterification reaction. The catalysts produced were characterized through the techniques, X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), thermogravimetric analysis (TG/DTG), desorption at programmed temperature of CO2 (TPD-CO2) and analysis by the method deconvolution of the DTG and TPD-CO2   curves. The biodiesel produced was characterized by 1H and 13C nuclear magnetic resonance spectroscopy (NMR 1H and 13C), TG/DTG using the deconvolution method on the DTG curves, density at 20 °C, kinematic viscosity at 40 °C and acidity. In order to better evaluate the yield of the reactions to obtain biodiesel from OCR with the catalysts, variations were applied in the following synthesis parameters: time (3-9h), catalyst concentration (2.5-10%) and alcohol/ oil (A/O) (9:1-18:1). The solid materials BPC and TPC presented a majority composition of potassium carbonate, and in the SPS it was found mainly potassium silicate and sodium silicate. The TPD-CO2 analyzes indicated a greater amount of basic sites in the SPS and BPC materials, with forces in the moderate to strong range. In the case of the TPC catalyst, the presence of weak sites was observed. The OCR biodiesel formed with the catalysts TPC, SPS and BPC showed conversions of 91.3%, 93.9% and 90.9%, respectively. Glycerol was converted into acetins using catalysts based on transition metal oxides. The 13C NMR spectra confirmed the synthesis by identifying the acetate carbonyl peaks present in the synthesized acetins. Therefore, in this work, the production of biodiesel was developed from a more environmentally friendly process, due to the use of green catalysts, residual cooking oil and obtaining products derived from residual glycerol.

9
  • DJALAN FRANÇA DE LIMA
  • Computational modeling of the interaction between calcium ions and scale-inhibiting species: understanding the anti-scaling mechanism.

  • Advisor : MIGUEL ANGELO FONSECA DE SOUZA
  • COMMITTEE MEMBERS :
  • EZEQUIEL FRAGOSO VIEIRA LEITÃO
  • DAVI SERRADELLA VIEIRA
  • FABRICIO GAVA MENEZES
  • JÚLIO COSME SANTOS DA SILVA
  • MIGUEL ANGELO FONSECA DE SOUZA
  • Data: Aug 30, 2022


  • Show Abstract
  • The deposition of scale salts, particularly calcium carbonates (CaCO3), on production equipment is a very challenging problem for the oil and gas industry. The process of deposition of scaling salts is often an intrinsic problem, occurring as a consequence of the physicochemical conditions in oil wells. In order to remedy the oil industries use chemical species called scale inhibitors to prevent the deposition process. The understanding of the molecular mechanism of action of inhibitors is not completely understood. Then, computational studies were carried out to calculate the electronic and structural properties of the interaction between scale inhibitors and calcium cations (Ca2+), in order to provide details at the molecular level about the mechanistic action of anti-scalants. For these studies, the approach of density functional methods combined with the implicit solvation model for the quantum electronic structure calculations was used. The thesis was divided into three distinct studies, involving the calculation of the binding energy between the Ca2+ ion(s) and inhibitory species, namely: (i) sodium hexametaphosphate, (NaPO3)6 – HMP; (ii) copolymer monomer poly(4-styrene-sulfonic acid-co-maleic acid) [P(SS-MA)] and anionic surfactant sodium dodecyl sulfate (SDS); and (iii) carboxymethylcellulose (CMC) and hydroxyethylcellulose (HEC) polymer monomers. For the species HMP, the pKa values of the (de)protonation process of the species (HPO3)6 were estimated, namely: pKa1 = –1.2; pKa2 = -0.98; pKa3 = +3.7; pKa4 = +5.6; pKa5 = +10.4; and pKa6 = +12.0. The values obtained by the theoretical calculations show good agreement with values of +6.2 (pKa4) and +9.2 (pKa5) obtained experimentally. In all cases the binding energies between the inhibitor species and the Ca2+  ion were compared with the binding energies of Ca2+···HCO3–  and Ca2+···CO32–. In (i) the complexes formed by the interaction between Ca2+  ions at each HMP coordination site, in their anionic forms H4(PO3)62− and H2(PO3)64−, are thermodynamically favorable. In (ii) the theoretical results suggest that the binding energies between the monomeric species of P(SS-MA) and Ca2+ ions are thermodynamically favorable if the coordination occurs through the carboxylate groups. However, the binding energy between the SDS and the Ca2+ ion is unfavorable in terms of the Gibbs energy. Furthermore, the cooperative interaction of the surfactant SDS and P(SS-MA) with the Ca2+ ion(s) can result in an exergonic complex. Finally, in (iii) the results of binding energy calculations between Ca2+ and CMC and HEC monomers suggest that the Ca2+ cation interacts more strongly with CMC than with HEC. This is because while the CMC monomer has carboxylate groups to interact with the cation, the HEC has only polar (non-anionic) groups. Furthermore, for this system, the interaction energy of the monomers with a cluster of [CaCO3]5 was calculated. Theoretical results suggest that the CMC monomer can replace the position of a CO32– ion in the cluster, but the HEC monomer does not have this ability.

10
  • JÉSSICA PIRES DE PAIVA BARRETO
  • STUDY OF EFFICIENCY OF PRODUCTION OF GREEN H2  SIMULTANEOUSLY WITH THE PRODUCTION OF STRONG OXIDANTS USING BORON DOPED DIAMOND ELECTRODE (BDD).

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • DJALMA RIBEIRO DA SILVA
  • ELISAMA VIEIRA DOS SANTOS
  • SUZANA MARIA LOURES DE OLIVEIRA MARCIONILIO
  • Data: Sep 5, 2022


  • Show Abstract
  • Electrochemical water splitting driven by renewable energy sources is considered to be a promising carbon-free pathway for the production of the “green” fuel hydrogen. Efforts for decarbonization are recurrent, so the use of electrochemical technology powered by renewable sources, such as photovoltaic cells (PV), wind turbines, among other alternatives, have increasingly attracted the attention of the scientific community. Despite the promises of such an approach, the process economics are not yet favorable. Faced with this scenario, propositions arise such as the integration of processes. The use of membrane divided electrochemical reactors is a well-known technology in hydrogen production (at the cathodic compartment). The proposal is the simultaneous production of green hydrogen with anodic reactions. Then, on the one hand, the supply of electrical energy to promote anodic reactions in the production of strong oxidants is an alternative to be considered for the parallel production of hydrogen, reducing energy consumption and costs; Being an eco-friendly sustainable process, if the electricity is produced by PV cells. On the other hand, the use of a boron-doped diamond electrode, in the anodic electrolytic compartment, can be considered a promising alternative, because the wastewater treatment, disinfection of water or electrosynthesis of oxidants can be attained. Thus, this work proposed the production of sulfate-based oxidizing species in the anode compartment with the simultaneous production of green H2 in the cathode compartment. Results clearly have demonstrated that higher production efficiencies, from 0.5 to 2.0 mM, of sulfate-based oxidizing species can be obtained depending on applied current densities, producing in parallel, from 0.2 to 0.8 L of pure hydrogen in 120 min. Application ex-situ of electrogenerated persulfate stored at lower temperatures has greater applicability than when stored at room temperature. The transition from “on-grid” to “off-grid” technology has some advantages such as cost reduction, ease of logistics and greater process portability and reproducibility. Sulfate-based oxidizing species solutions can be used as an off-grid technology to degrade pollutants, thus, increasing the high-added value of the technology.

11
  • DANIELE DA SILVA OLIVEIRA
  • Beta EMT FAU Zeolites, Hierarchization, Glycerol Dehydration, Zeolite Templated Carbon - ZTC

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • ELEDIR VITOR SOBRINHO
  • ADONAY RODRIGUES LOIOLA
  • CHRISTIAN WITTEE LOPES
  • ALEXANDER SACHSE
  • VINÍCIUS PATRÍCIO DA SILVA CALDEIRA
  • Data: Sep 6, 2022


  • Show Abstract
  • The excess of glycerol as a by-product of biodiesel has become an obstacle in the biodiesel production chain, creating new challenges for its sustainable use. Thus, the use of hierarchical zeolites to obtain higher value-added products from glycerol is a promising alternative, due to its properties such as high specific area, acidity, shape selectivity, with a shorter diffusion path in the micropores and an improved access to micropores through the generated mesopores. Thus, the objective of this work was to generate mesopores in the zeolites *BEA, EMT and FAU by an economical and easy method, and to evaluate their catalytic activity in the glycerol dehydration reaction, and to obtain Zeolite Templated Carbon - ZTC in order to obtain higher added value products. Zeolites were hierarchical by post-synthesis treatment. EMT zeolite was first hierarchical with NH4F. *BEA zeolite was hierarchical with NH4OH, hierarchical zeolites were applied in the glycerol dehydration reaction showing excellent conversion (EMT 60.83% and Beta 99.58%), being selective to acetaldehyde, acrolein and acetol. The ZTCs were obtained using the hierarchical FAU zeolite and glycerol as a precursor for the first time. Glycerol presented itself as an innovative and efficient precursor for obtaining ZTC.

12
  • MANUELA SILVA MARTINS DE OLIVEIRA
  • Hierarchically Structured Zeolites: A Study of Mesoporosity Insertion via Mechanochemistry.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • ADONAY RODRIGUES LOIOLA
  • ANTONIO SOUZA DE ARAUJO
  • EDUARDO RIGOTI
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: Sep 16, 2022


  • Show Abstract
  • Structurally, zeolites – when considered as aluminosilicates – basically consist of a three-dimensional network formed from silicon and aluminum tetrahedra that are interconnected by means of oxygen atoms. Due to their diverse properties and characteristics, it can be said that zeolites are the most used catalysts in the industry; however, the intrinsic microporosity of these materials has limited their application aimed at processing larger molecules. In this work, the influence of mechanochemical methods in obtaining zeolitic materials with hierarchical pore structure was studied, through the insertion of mesoporosity via dry grinding in a ball mill, seeking to obtain zeolites with greater accessibility of active sites. The zeolitic materials used in this process were Mordenite, Linde Type X and USY. In the application of the mechanochemical method, the variables rotation speed (200, 400 and 600 rpm) and rotation time (20, 40 and 60 min) were evaluated. For the mordenite zeolite, the acid materials previously submitted to a rotation speed of 200 rpm and a rotation time of 60 min showed more acceptable structural and textural maintenance compared to other milling studies. In addition, it kept the specific area practically unchanged and a considerable increase in the surface area and volume of mesopores. For Linde Type X zeolite, the low Si/Al ratio presented by the material ended up causing a structural collapse; which in turn made it difficult to apply this material. Finally, USY zeolite presented a profile similar to Mordenite zeolite materials, exhibiting less incisive structural changes at lower rotation speeds and times.

13
  • JUSSARA CÂMARA CARDOZO
  • Electrochemical oxidation of emerging pollutants: voltammetric studies and green hydrogen production.

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • ELISAMA VIEIRA DOS SANTOS
  • MARCO ANTONIO QUIROZ ALFARO
  • SUZANA MARIA LOURES DE OLIVEIRA MARCIONILIO
  • Data: Sep 30, 2022


  • Show Abstract
  • Electrochemical advanced oxidative processes are effectively used to treat effluents containing organic pollutants. In this work, the electrochemical oxidation of pharmaceuticals and dye, in aqueous media was studied. The electroanalytical studies showed that for the drug Olanzapine, both direct and indirect oxidation processes can occur using the boron-doped diamond electrode, confirming the versatility of this electrode. The parameters investigated were the influence of the supporting electrolyte, pH and current density while the analytical methods used to analyze the degradation of the pollutants were UV-Vis spectroscopy, chemical oxygen demand (COD), total organic carbon (TOC) and high-efficiency chromatography (HPLC), obtaining results with a removal percentage higher than 90%. For the production of hydrogen, the electrochemical experiments were performed in an electrochemical cell of two compartments separated by a Nafion membrane, where it was possible to perform the oxidation of the calcon dye and simultaneously produce hydrogen in the cathode compartment. The results of the electrochemical oxidation of calcon dye, using a BDD electrode demonstrated that the application of this electrode proved to be very efficient, where the significant concentration of hydroxyl radicals -OH formed in the BDD effectively attacks the dye, promoting a great performance of oxidation, since it not only reduced the color of the effluent but also led to its mineralization. Regarding hydrogen production, the results showed that the speed of H2 production is dependent on the applied current and electrolysis time, showing faradaic efficiency of over 90% during the process.

14
  • FRANCIMAR LOPES DE SOUSA JUNIOR
  • In vitro biological activity of copper and zinc complexes with vanilloid results: Characterization, superoxide generation assay, anticancer and antiparasitic activities.

  • Advisor : FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • JOSE LUIS CARDOZO FONSECA
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • DANIEL DE LIMA PONTES
  • JOSÉ CLAYSTON MELO PEREIRA
  • VERONICA DA SILVA OLIVEIRA
  • Data: Oct 21, 2022


  • Show Abstract
  • Metallic compounds containing vanilloid derivatives have gained interest in medicinal inorganic chemistry, due to the biological properties of this class of ligands, having as an example the ability to generate specific reactive oxygen (SRO). In this context, the present work aims to synthesize and characterize complexes of the type [M(phen)(L)2], where M=Cu2+ and Zn2+, and L=o-vanillin (ovan) and ovani, in which the latter is a schiff base derived from the reaction of o-vanillin with isoniazid. In addition, the [Cu(phen)(ovan)2](3) and [Zn(phen)(ovan)2] (4) complexes were tested against AGS and HeLa cancer strains, as well as Tryponosomacruzi strains. From the vibrational spectra of the complexes [M(phen)(ovan)2], the mode of coordination of the ovan was determined by the variation of the energy of the carbonyl band, in addition, for the compounds [M(phen)(ovani)2], it was observed the presence of the hydrazide C=O band at 1709 cm-1 and the imine band (C=N) around 1630 cm-1, which are indicative of the formation of the Schiff base. From the study of cyclic voltammetry, it was observed that the [Cu(phen)(ovan)2], presented an E1/2 of -171 mV, demonstrating within the redox range of the biological medium, with this, the test of the tetrazolium-nitroblue chloride (NBT), using glutathione as a reducing agent, showed a positive response to the formation of O2-. Complex (3) was more effective in both strains with IC50 of 6.19 and 5.63 µM, for AGS and HeLa respectively. Regarding the antiparasitic test, a dose-dependent behavior was observed for both compounds, obtaining an inhibitory concentration of 5.03 for (3) and 108.40 µM for (4) respectively.

15
  • LARISSA CASTRO DIÓGENES
  • Development of carriers for LTA zeolite and hydroxyapatite based fertilizers with slow release of nitrogen, phosphorus and potassium.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • ANTONIO SOUZA DE ARAUJO
  • LUCIENE DA SILVA SANTOS
  • LINDIANE BIESEKI
  • ADONAY RODRIGUES LOIOLA
  • ISABEL DIAZ CARRETERO
  • Data: Nov 3, 2022


  • Show Abstract
  • Population growth and the growing need for food require greater efficiency in the use of nitrogen (N), phosphorus (P) and potassium (K) present in fertilizers, which can be increased through the development of composites that slowly release N, P and K. To obtain the composite, bentonite and illite clays, LTA zeolites and clinoptilolite were tested as potassium carriers. The materials were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR). The leached potassium content in soil columns was determined by inductively coupled plasma atomic emission spectrometry (ICP-OES). Among the materials tested, LTA zeolite showed the best potassium adsorption capacity, with a slow and gradual release behavior. LTA zeolite together with hydroxyapatite and urea constitute the synthesized composites that were characterized by XRD, XRF, FTIR and scanning electron microscopy (SEM-FEG). XRD analysis with Rietveld refinement confirmed that the composite samples present hydroxyapatite in two monoclinic and hexagonal phases, in addition to the phases referring to zeolite LTA and urea, which are also confirmed by the FTIR and SEM results. The SEM images show the rod-shaped hydroxyapatite-urea crystals lining the cubic surface of the zeolite LTA.

16
  • DAYANA PATRÍCIA DA SILVA PENHA MACEDO
  • SYNTHESIS, CHARACTERIZATION AND STUDY OF THE REACTIVITY OF RUTHENIUM NITROSYL COMPLEX WITH POSSIBLE CYTOTOXIC ACTION

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DANIEL DE LIMA PONTES
  • DULCE MARIA DE ARAUJO MELO
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • SIBELE BERENICE CASTELLA PERGHER
  • SÉRGIO XAVIER BARBOSA ARAÚJO
  • WENDY MARINA TOSCANO QUEIROZ DE MEDEIROS
  • Data: Dec 21, 2022


  • Show Abstract
  • Nitric oxide is a signaling molecule that has important chemical and biological characteristics for the development of new cytotoxic agents, such as ruthenium nitrosyl complex which upon receiving a photochemical stimulus, can release nitric oxide in the body and generate reactive species that destroy target cells in a treatment known as photodynamic therapy. In this way, the synthesis, characterization and study of the reactivity of nitrosyl complex of the cis-[Ru(bpy)(phen)L(NO)](PF6)4 type is presented, in which L are biological and cationic dyes such as Nile blue and safranin, bpy = 2,2'-bipyridine and phen = 1,10'-phenanthroline. The complexes were obtained from the cis-[Ru(bpy)(phen)Cl2] dissolved in the 1:1 proportion of water and ethanol with the addition of the ligands under study. According to the electronic spectra, in methanol, it was possible to verify the intraligand bands of dyes, bipyridine and phenantroline, as well as the charge transfer band from the metal to the polypyridine ligands in the region of 420 nm. In the vibrational spectra in KBr pellets, the stretch of NO+ in 1926 and 1938 cm-1 is verified for the complexes with Nile blue and safranin, respectively, indicating that the nitric oxide is coordinated to the metallic center in the linear form. When analyzing the cyclic voltammograms of nitrosyl complexes, in NaTFA 0.1 mol L-1, there is a single almost reversible process related to the NO+/0 redox pair. Regarding the reactivity was done the acid-base equilibrium, noting that at pH 9.4 and 8.6 there is the conversion of nitrosyl to nitrite for the complexes with Nile blue and safranin, in that order. The release of nitric oxide from the coordinating sphere was analyzed by electrochemistry by square wave voltametry and through the photochemical stimulus with red light, the release occurs by a chemical reaction that reduces the binding from NO+ to NO0 and due to the weakening of the bond RuII - NO0, this is released.

2021
Dissertations
1
  • FERNANDO VELCIC MAZIVIERO
  • INFLUENCE OF PROMOTERS ON Ni-X/Al2O3 (X= Mn, Mg, Ce and P) CATALYSTS APPLIED IN DRY REFORMING OF METHANE PROCESS.

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • GILVAN PEREIRA DE FIGUEREDO
  • RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Jan 5, 2021


  • Show Abstract
  • The dry reforming of methane process (RSM) is a technology that uses two of the main greenhouse gases (CH4 and CO2) for the production of syngas (H2 and CO), which has several industrial applications in addition to hydrogen be considered a source of clean and highly efficient energy, giving it high commercial value. Nickel-based catalysts based on alumina were prepared containing the Mg, Mn, Ce and P promoters, chosen due to their different chemical properties. The synthesis method used for the support was microwave assisted combustion where urea was used as fuel for the process in quantities below the stoichiometric point in order to obtain lower crystallinity Al2O3 in the gamma phase. The promoters and the active phase were incorporated into the support using the sequential impregnation method via incipient wetness, ending the synthesis stage with heat treatment at a temperature of 550 ° C for three hours. The obtained materials were characterized by X-Ray Diffraction (XRD) to elucidate the phases obtained in each catalyst and to evaluate the influence of the promoters on the material structure, spectroscopy in the infrared region with Fourier transform (FTIR) to prove the presence of phosphorus in the catalyst and evaluate the species it is in, Temperature Programmed  Reduction (TPR) to identify the reducible species present and the reduction profile of the catalysts and in-situ X-Ray Diffraction using a synchrotron radiation source to analyze the variation of the structure during the activation step. The catalytic test was carried out at a temperature of 700 °C with GHSV = 100 L.g-1.h-1 for 20 hours and the carbon formed was quantified through thermogravimetric analysis. The results indicated that successive steps of solubilization and calcination resulting from the sequential impregnation method cause structural changes, altering the degree of crystallinity of the Al2O3 support in the catalyst with the promoters. In the catalytic stability test, the materials containing Mn promoter obtained the best conversion value due to the presence of MnO2, which favors parallel reactions of methane decomposition during the RSM process. The catalysts containing phosphorus and cerium produced smaller amounts of coke compared to the standard catalyst due to the interaction of promoters with carbon on the surface of the catalytic sites, in addition to acting on the particle size obtained for the active phase.

2
  • LIDIANE GONÇALVES DA SILVA
  • HIV. Pregnant women. ATR-FTIR. Multivariate Analysis. GA-LDA

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • KASSIO MICHELL GOMES DE LIMA
  • FABRICIO GAVA MENEZES
  • EDGAR PERIN MORAES
  • ROBINSON SABINO DA SILVA
  • Data: Jan 21, 2021


  • Show Abstract
  • The human immunodeficiency viruses (HIV) is the cause of a nfection that can compromise the immune system. The main concern with pregnant women with the virus is the vertical transmission that can occur during pregnancy, during labor and even during the breastfeeding period. The risk of vertical transmission can be reduced through early diagnosis. The colorimetric assays used for the detection of the virus have high costs and are quite laborious, making it necessary to develop fast and low-cost methodologies for the detection of HIV. Herein, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) combined with multivariate analysis was used to distinguish HIV-infected patients (n = 40) from healthy controls (n = 80) in a total of 120 blood plasma samples. PCA-LDA, PCA-QDA, PCA-SVM, GA-LDA, GA-QDA, GA-SVM, SPA-LDA, SPA-QDA and SPA-SVM were used as classification tools. The algorithms had their performances evaluated according to precision, sensitivity, specificity, F-score and G-score. PCA-SVM, SPA-LDA and GA-LDA algorithms were the ones that obtained the most satisfactory results for the discrimination of the samples with accuracy of 81%, 75% and 88.9% respectively. GA-LDA was the best classification algorithm, presenting the best values of sensitivity (83%), specificity (92%), F-score and G-score (87%). The results suggest the potential of ATR-FTIR spectroscopy combined with multivariate analysis as an alternative tool for HIV screening in pregnant women based on blood plasma, being a low-cost, fast and reagent-free method

3
  • MIKAELY LIZANDRA MOREIRA DE ASSIS
  • SYNTHESIS, CHARACTERIZATION AND APPLICATION OF THE PALYGORSKITE/TITANIUM DIOXIDE NANOCOMPOSITE IN PHOTOCATALYTIC DEGRADATION OF TEXTILE DYES

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • JOÃO SAMMY NERY DE SOUZA
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • NEDJA SUELY FERNANDES
  • Data: Jan 28, 2021


  • Show Abstract
  • One of the biggest environmental problems is due to industrial activity, in which the contamination of water resources with post-production waste occurs, causing adverse effects to the ecosystem. The effluents of industrial dyes present a great risk to the health of biodiversity, in most cases, they are toxic, persistent organic compounds that are difficult to remove by conventional treatments, in addition to presenting themselves as carcinogenic materials. The development or improvement of techniques for effluent treatment are of great interest, since the objective is to search for low-cost synthesis routes that generate less toxic waste or by-products. The photocatalytic discoloration of industrial dyes, Novacron blue (AZN) and Novacron yellow (AMN), were investigated using TiO2-based composites supported on natural palygorskite (TiP10 and TiP30). The method consisted of synthesizing the composites starting from a physical mixture of TiO2 and natural palygorskite in the presence of alcohol, for impregnation through calcination under conditions of temperature equal to 450ºC and atmospheric air. The characterization techniques used in this work were: FTIR, DRX, MEV, particle size analysis and zeta potential. The photocatalysis for the AZN dye was investigated through the application of a factorial experimental design 24, aiming at the best experimental conditions and finally applying them in another AMN industrial dye. The investigated AZN concentrations were 10 ppm and 30 ppm, the composites were synthesized using 10 and 30% (m/m) titanium dioxide in palygorskite, the two pH values were 2 and 6 and the light intensities were powers 9 and 18W are used. Tests performed at: pH 2.0; TiP30 composite; 18W power and 10 ppm of dye, showed 100% removal of both dyes in 90 min. The decolorization process followed the pseudo-first order kinetic model and the apparent constant (kapp) was 0.0216 min-1 and 0.0193 min-1 for the AZN and AMN dyes, respectively. The results of the final treatment cost for the tests were feasible in terms of efficiency and economy. Since, under the best parameters studied, the photocatalysis of AZN and AMN had an energy consumption of 0.135 kWh / dm3 and a final cost of R$ 0.0895.

4
  • LUIZ FELIPE DA HORA
  • Obtaining nanolatics via semi-continuous emulsion polymerization and its application as a surface modifier in dyeing with soy protein fibers.

  • Advisor : JULIANA DE SOUZA NUNES
  • COMMITTEE MEMBERS :
  • JOSE HERIBERTO OLIVEIRA DO NASCIMENTO
  • JOSE LUIS CARDOZO FONSECA
  • JULIANA DE SOUZA NUNES
  • ROSANGELA DE CARVALHO BALABAN
  • ZILVAM MELO DOS SANTOS
  • Data: Jan 29, 2021


  • Show Abstract
  • In this work, nanolatexes were produced by semicontinuous emulsion polymerization. Parameters such as monomeric composition, initiator and surfactant type were investigated in order to obtain a nanolatex with small particle size and high functionalized surface area. Afterwards, the nanolatex was used as a binder to improve the dyeing process of soybean protein fiber (SBF) fabric with a cationic dye (Basic Red 46). The best monomer composition was the one with the following ratio in mass BA/MMA/MAA (5:4:1). The best performance as an initiator was presented by APS, and the SDS had the best performance as a surfactant. The polymeric particles were analyzed by several techniques such as: gravimetry, DLS, SEM, TEM, FTIR, ELS, tensiometry, and conductometry titration. Nanolatexes with particle size as small as 29 nm and surface charge up to 93.8 μC/cm2 were obtained through emulsion polymerization technique. The presence of nanolatex on the surface of the soybean fiber was verified by FTIR and TGA analysis. The nanolatex efficiency as an additive to modify the dyeing process was evaluated by colorimetric data using the Kubelka-Munk equation. Preliminary tests showed that the fabrics functionalized with nanolatex had an increase of up to 13% in color intensiity, showing its ability to be used as surface additive in the dyeing proccess.

5
  • MIZRAIM BESSA TEIXEIRA
  • Rice husk ash influence in cement slurries for early stages offshore well cementing, an economic and sustainable alternative.

     

  • Advisor : JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • COMMITTEE MEMBERS :
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • RODRIGO CESAR SANTIAGO
  • LECH WALESA OLIVEIRA SOARES
  • Data: Mar 8, 2021


  • Show Abstract
  • The use of rice husk ash (RHA) in cementitious formulations has been widely studied in the literature in recent years. There are several applications for this by-product of the food industry. Some examples are the use of ash as a fertilizer, as a source of amorphous silica, as a source of pozzolanically active biomass and in the formulation of cement pastes for onshore oil wells, from medium to high temperature (50-200 ° C). However, little has been investigated about the use of RHA for low temperature systems, as is the case with the cementation processes of the initial phases of offshore wells, which generally occur at temperatures around 3-5 ° C. This study aims to analyze the influence of the addition of RHA in cement matrices destined for offshore operations that occur between 3-5 ° C. Cement pastes with a fixed density of 13.5 lb / gal (1.62 g / cm³), containing RHA (0%; 10%; 20%; 30%; 40% and 50%), were prepared and technological tests conducted (Resistance to Compression, UCA, Thickening Time, Stability, Rheology) in order to verify the feasibility of using ash for low temperature oil wells. The tests showed that the use of ash provided hydrated product with 96.8% of the standard paste resistence (Portland Cement  + 2% bentonite), as well as improving the stability and rheology of the paste in relation to those without addition. The addition of 50% ash reduced the percentage of free water in the paste by 5.6%, compared to 0% RHA. The formulation containing 50% RHA showed adequate resistance gain profile, with a pumpability time of 23h (50Bc). The stability test proved that the addition of RHA increases the stability of the paste, reducing the top drawn and avoiding decantation of the paste. RHA is a sustainable alternative for applications in low temperature environments, such as early stages of marine oil wells, considerably reducing cement consumption (15% by weight in relation to standard paste), thus contributing to the reduction in emissions of CO2 in the atmosphere due to cement production. Finally, RHA proved to be extremely economically viable. Compared to standard formulation, the use of 50% ash reduced the cost of the barrel by 23.7%, which represents savings of U$ 7.49 for each barrel (bbl).

6
  • RAMONI RENAN SILVA DE LIMA
  • OBTAINING SOYBEAN OIL BIODIESEL USING HETEROGENEOUS CATALYST FROM PONKAN TANGERINE PEEL ASHES (C. RETICULATA BLANCO)

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • ANNE GABRIELLA DIAS SANTOS
  • IVONEIDE DE CARVALHO LOPES BARROS
  • LUCIENE DA SILVA SANTOS
  • VALTER JOSE FERNANDES JUNIOR
  • Data: Mar 12, 2021


  • Show Abstract
  • The advance of global energy demand has intensified environmental problems caused by the use of fossil fuels and has been driving the search for and development of greener matrices, which are being used in order to minimize environmental impacts and human health. This work proposed a sustainable process for the production of biodiesel, an alternative fuel to diesel, with the use of a heterogeneous, green catalyst, called CT, derived from a residual biomass, from the bark of 'Ponkan' mandarin (Citrus reticulata Blanco). Through d-optimal experimental planning to obtain soybean biodiesel, process parameters such as: methanol/oil molar ratio, catalyst concentration, temperature and reaction time were optimized. Initially, three catalyst samples were prepared by calcination of the ashes of the tangerine barks at a time of 4h, CT7 (700 ° C), CT8 (800 ° C) and CT9 (900 ° C), and after preliminary tests, the yields (m/m) in biodiesel were 79.77, 77.58 and 77.40 %, respectively. The mass catalyst yield obtained for each temperature (700, 800 and 900 °C) starting from 50 g of bark were 3.76, 1.54 and 0.98%, respectively. The catalysts were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM-FEG), X-ray dispersive energy (EDS), CO2 desorption at programmed temperature (TPD-CO2), thermal analysis (TG/DTG) and Hammett's basicity test.  The quality of biodiesel was evaluated according to the standard procedures established by ASTM (American Society for Testing and Materials) for the properties of kinematic viscosity and density. The XRD patterns of the CT catalyst showed the peaks associated with the characteristic phases of K2CO3, K2O, K2Ca(CO3)2, SiO2, Na2O confirmed by XRD and FRX, which identified large proportions of these oxides. TPD-CO2 analysis demonstrated the presence of weak and moderate base sites in the CT catalyst. Good thermal stability was observed through the TG/DTG curves. The optimized conditions generated by the response surface were: 3 h reaction time, catalyst concentration of 3.5% m/m, molar ratio of 15: 1 (methanol: oil) and temperature of 64 ° C. For these optimized conditions, the conversion of the reaction quantified by 1H NMR was greater than 87% and the catalyst presented reuse capacity of up to 5 times.

7
  • ALANE PRISCILLA AMÉRICO DOS SANTOS
  • Biotióis; 2,3-dicloro-6,7-dinitroquinoxalina; Quimiodosímetro; Estudo computationa

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • RENATA MENDONÇA ARAUJO
  • LIVIA NUNES CAVALCANTI
  • GUTTO RAFFYSON SILVA DE FREITAS
  • Data: May 10, 2021


  • Show Abstract
  • Biothiols, such L-cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), are highly relevant species in many biological processes, and therefore, the development of methodologies for the selective detection of these biothiols is a relevant research field. This work aims to provide theoretical support to the results obtainted in our research group for the L-cysteine (Cys) sensing ability of the chemodosimeter 2,3-dichloro-6,7-dinitroquinoxaline (DCDNQX), with an extension for its reactions with Hcy and GSH. The method M06-2X with 6-311+G (2d,p) basis set was applied for all calculations. They were evaluated several mechanistic proposals taken into account the versatility of Cys, Hcy and GSH as nucleophiles, including the possibility of nucleophilick attack by amino ad/or thiol groups, for both mono- and dissubstitution, including intramolecular cyclizations. Geometric parameters, inclding transition states for all molecules and reactions were optimized searching for thermodynamics and kinetics information. The results indicated the preference for the S- over N-attack, and the cyclized product being the most stable. The effect of structure on intramolecular cyclization was also studied.

8
  • JOÃO EDSON TAVARES SOUSA DANTAS
  • OBTAINING FUNCTIONALIZED MESOPOROUS CARBONS FOR ELECTROCHEMICAL SENSORS APPLICATION IN THE DETECTION OF EMERGING CONTAMINANTS

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • FERNANDO JOSÉ VOLPI EUSÉBIO DE OLIVEIRA
  • TIAGO PINHEIRO BRAGA
  • Data: Jul 16, 2021


  • Show Abstract
  • THE MESOPOROUS SILICA SBA-15 WAS SYNTHESIZED THROUGH HYDROTHERMAL METHOD AND USED AS TEMPLATE FOR THE SYNTHESIS OF THE MESOPOROUS CARBON, CMK-3, THROUGH NANOCASTING ROUTE. THE SYNTHESIZED MATERIALS KEPT THE HEXAGONAL PORE STRUCTURE. THE CMK-3 WAS ORGANOFUNCTIONALIZED USING MALEIC ANHYDRIDE AND REDUCING REAGENTS IN ORDER TO GENERATE CARBOXYLIC GROUPS AND TO CAUSE ITS REDUCTION, CMK-3RED. BOTH SYNTHESIS AND MODIFICATION OF MESOPOROUS CARBONS WERE PROVEN BY X RAY DIFFRACTOMETRY (XRD), THERMOGRAVIMETRY (TG), RAMAN SPECTROSCOPY AND SCANNING ELECTRON MICROSCOPY (SEM). THE XRD SPECTRA CONFIRM THAT THE CARBONACEOUS MATERIAL CMK-3 KEPT THE SAME STRUCTURE MORPHOLOGY OF SBA-15, CONFIRMED BY THE SEM IMAGES. THE FUNCTIONALIZED CMK-3RED HAD MORPHOLOGY ALTERATION DUE TO ITS CHEMICAL MODIFICATION, WHICH WAS CONFIRMED BY XRD, SEM AND TG. FOR THE ELECTROCHEMICAL DETECTION OF CAFFEINE AND SALICYLIC ACID ANALYTES WAS USED AN GLASSY CARBON ELECTRODE, WHICH WAS MODIFIED THROUGH DROP CASTING METHOD WITH THE MESOPOROUS CARBONS. DIFFERENTIAL PULSE VOLTAMMETRY WAS USED AS ELECTROCHEMICAL DETECTION TECHNIQUE, EXHIBITING IMPROVEMENT OF SENSITIVITY TO ANALYTES, BOTH INDIVIDUALLY AND SIMULTANEOUSLY, IMPROVING IN 10% WITH CMK-3 AND IN 30% WITH CMK-3RED.

9
  • GIDIÂNGELA CECÍLIA CAVALCANTE DA SILVA LIMA
  • SYNTHESIS OF ZEOLITE SILICOALUMINOPHOSPHATE (SAPO-11) USING FLUORESCENT LAMP WASTE

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • ANTONIO SOUZA DE ARAUJO
  • MARIELE IARA SOARES DE MELLO
  • SIBELE BERENICE CASTELLA PERGHER
  • ÍRIA ALMEIDA LEAL BASSAN
  • Data: Jul 22, 2021


  • Show Abstract
  • The fluorescente lamp is a material widely used in society, after consumption because it is treated as a material that contains heavy metals, such as Mercury, its inappropriate disposal causes great environmental impacts. The residue from the fluorescente lamp (phosphorous poder) was supplied by the company BQMIL (Brasil Química e Mineração Industrial Ltda), located in Mossoró/RN, after the processo f crushing the lamps, the substances are separated into categories such as: glasses, gases, electrodes (electrons), bakelitic isolation and phosphoric poder, this phosphoric poder undergoes a distillation process to recover mercury, leaving the solid residue. In order to use and manage the phosphoric poder residue, this was used material in the synthesis processo f zeolites, which are composed of tetrahedra of AlO4 and SiO4, linked together by sharing common oxygen atms. The studied residue has in its chemical composition silicone(Si), aluminum (Al) and phosphorus (P), which contributed to the synthesis of silicoaluminophosphates (SAPO-11) zeolites, structure AEL, as na alternative source of Si, Al and P, by means of the conventional hydrothermal process. The methodology applied in the studies, parameters such as the source of additional aluminum in the synthesis, neutral alumina or aluminum hydroxide, temperature and crystallization time were varied. The results of the syntheses were characterized by X-ray diffraction (XRD) techniques, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR), scanning eléctron microscopy (SEM) and textural analysis. The rearch carried out in this work is na innovation in the SAPO-11 synthesis, adding value to the waste and transforming it into a new material, thus reducing costs in syntheses and mitigating environmental impacts.

10
  • RENILSON DE OLIVEIRA MAPELE
  • APPLICATION OF HS-GC-FID IN ANALYSIS OF SOIL SAMPLES CONTAMINATED WITH COMMERCIAL GASOLINE

     

  • Advisor : VALTER JOSE FERNANDES JUNIOR
  • COMMITTEE MEMBERS :
  • VALTER JOSE FERNANDES JUNIOR
  • ANTONIO SOUZA DE ARAUJO
  • GLAUBER JOSÉ TUROLLA FERNANDES
  • Data: Jul 27, 2021


  • Show Abstract
  • This work aimed at evaluating the application of the HS-GC-FID technique for analysis of soil samples contaminated with gasoline. For this, samples of five types of soils from Rio Grande do Norte region were inserted in vials, contaminated with commercial gasoline, in the proportion of 3g soil/200 µL gasoline, and analyzed via HS-GC-FID (Shimadzu GC 2010). The samples were left open at room temperature, being sealed only at the time of each analysis. The data obtained from the chromatograms showed that the hydrocarbon concentration decay profile with time can be given by an exponential decay model of the type y = y0 + α e-x/β (R² > 0.99). The TG/DTG data showed that the organic composition of the soil had a maximum value of 3.8% and a maximum moisture content of 1.0%. The XRD and XRF data showed that the main components of the soil are, respectively, silicon, aluminum and iron, present in the form of oxides.

     

11
  • RODRIGO VICTOR BARBOSA
  • THERMOANALYTICAL EVALUATION OF POLYPROPYLENE DEGRADATION ON EXPANDED PERLITE COMPOSITE MATERIALS IMPREGNATED WITH CERIO, H-Y ZEOLITE AND THE COMPOSITE/ZEOLITE MIXTURE

  • Advisor : VALTER JOSE FERNANDES JUNIOR
  • COMMITTEE MEMBERS :
  • VALTER JOSE FERNANDES JUNIOR
  • ANTONIO SOUZA DE ARAUJO
  • GLAUBER JOSÉ TUROLLA FERNANDES
  • Data: Jul 29, 2021


  • Show Abstract
  • ABSTRACT: The objective of this work was to evaluate the thermal degradation of polypropylene on the composite of expanded perlite impregnated with cerium oxide, hereinafter referred to as Ce-PER, as well as to compare it with the degradation of PP when using a commercial HY zeolite and a mixture of Ce-PER with HY. Cerium oxide was added to the expanded perlite by means of the excess solvent co-impregnation method. The materials were analyzed by the techniques of XRD, XRF, SEM, TG/DTG and acidity test by thermal desorption of n-butylamine. The degradation profile of polypropylene was evaluated in a thermobalance. The degradation of PP was catalyzed when mixtures containing 30%H-Y + PP and 15%H-Y + 15%Ce-PER + PP were used. On the other hand, PP received a thermal stabilization effect when using the mixtures containing 10% and 30%Ce-PER + PP. The acidity analysis yielded the total acid site density values for zeolite H-Y (2,30 mmol) and for Ce-PER (0,2 mmol).

12
  • RANAYANNE SUYLANE PEREIRA CAMPOS
  • CHEMICAL CHARACTERIZATION OF IMBURANA EXTRACT (COMMIPHORA LEPTOPHLOEOS) AND ITS USE IN THE GREEN SYNTHESIS OF CuFe2O4 PARTICLES.

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • RENATA MARTINS BRAGA
  • GILVAN PEREIRA DE FIGUEREDO
  • RODOLFO LUIZ BEZERRA DE ARAÚJO MEDEIROS
  • Data: Jul 29, 2021


  • Show Abstract
  • Copper Ferrite Nanoparticles (CuFe2O4) were synthesized by a green route using the aqueous and hydroethanolic extract of the bark of Commiphora Leptophloeos, popularly known as “Imburana”, a plant native to the Caatinga region in Brazil. The phytoconstituents present in the extract were used as complexing and chelating agents for the synthesis of CuFe2O4 particles. All characterizations of the bark and plant extract were performed by FTIR, TG, UV/Vis and HPLC-MS/MS analyses. The particle size, morphologies and properties of the materials obtained were analyzed by DRX, SEM, UV/Vis, FTIR and Mossbauer spectroscopy. The present study intends to demonstrate the effectiveness of the use of natural extracts as providers of secondary metabolics for the reduction and stabilization of nanomaterial structures of metallic oxides, in this case, Ferrites using an ecologically correct and economically viable green synthesis route. They were identified as secondary metabolites in acid and flavonoid extracts. The presence of quinic acid, eriodictiol, catechins, quercetins and luteolins showed good efficiency and action as complexing and chelating agents for the synthesis of CuFe2O4 particles.

13
  • WILLIAN BARBOSA LIMA DO NASCIMENTO
  • SYNTHESIS OF POLYMER NANOPARTICLES FOR APPLICATION IN CEMENT PASTE OF THE OIL WELL

  • Advisor : JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • FABÍOLA DIAS DA SILVA CURBELO
  • JULIANA DE SOUZA NUNES
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • Data: Jul 30, 2021


  • Show Abstract
  • New additives applied to wells cementing have been developed in search of more and more efficient paste systems for application in critical scenarios, especially those cases where the risk of gas migration is involved. The present work deals with the development of a new technology applied to the cementation of oil wells. A nanolatex sitentized from emulsion polymerization that contains polystyrene particles with a size of approximately 65.9 nm, containing solids content close to 19% and low PDI values (less than 0.160). These are particles that have proven effective as additives to cement pastes, particularly as filtrate controllers for well scenarios with a risk of gas migration. The nanolatex were named according to solids concentration, ranging from 15.80 % (seed 1) to 19.8% (seed 6). The nanolatex were characterized by gravimetry (analysis done to determine polymer conversion and solid content), dynamic light scattering (DLS - analysis of particle size and particle number), polydispersity index (PDI - analysis of the homogeneity of the particle size of the system), zeta potential (analysis of colloidal stability). The cement pastes were characterized by static filtration and rheological tests. The cement paste additivated with 1.0 gpc (gallon per cubic foot of cement) of seed 7 showed consistency below 30 UC up to 199 °F. The filtrate and plastic viscosity tests showed values within acceptable ranges for application in cementing operations, 44mL/30min and 112 cP, respectively. Based on the results, the developed nanolatex presents itself as a potential additive for application in oil wells with fluid-loss and gas migration risk.

14
  • MARIA APARECIDA AIRES DE LIMA SARAIVA
  • Synthesis and characterization of tetracyan complexes - Na2[Fe(CN)4(L)2] - in which L are the Pyrazinamide and Isoniazid ligands

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • SÉRGIO XAVIER BARBOSA ARAÚJO
  • CARLOS ALBERTO MARTINEZ HUITLE
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • TIAGO PINHEIRO BRAGA
  • Data: Jul 30, 2021


  • Show Abstract
  • The growing number of bacteria resistant to conventional antibiotics has led the scientific community to seek more effective, selective drugs that cause less side effects. In this context, the development of coordination compounds for pharmacological purposes has been a great resource in the fight against resistant microorganisms due to the coordination of metal cations to significantly alter the physiological profile of drugs; making them more active than the free binder, reducing side effects and leading to a reduction in microbial resistance. Given the above, the present work aims to synthesize and characterize iron complexes of the type Na2[Fe(CN)4(L)2] in which L are the ligands, amino, pyrazinamide and isoniazid. The tetracians were obtained from the precursor compound NAT211 - Na2[Fe(CN)4(NH3)2] - dissolved in water followed by the addition of the binders, under stirring. Through vibrational spectroscopy in the infrared region, it was possible to detect the characteristic signals of the ligands coordinated to the metallic center, such as: cyan in the region between 2011 and 2094 cm-1; amino at 3288 cm-1; pyrazinamide in the range of 3412 to 1477 cm-1; and isoniazid from 3302 to 1554 cm-1. The electronic spectra in the UV-Vis region of the complexes showed bands of the type, d-d at 439 nm for the precursor; 378 nm for the compound with the pyrazinamide linker (NAT212) and 303 nm for the complex with the isoniazid (NAT213). The cyanide charge transfer bands (MLCT) are observed between 218 and 210 nm in the synthesized compounds. The MLCT of the N-heterocyclic ligands appear in 494 and 442 nm referring to NAT212 and NAT213, in that order. The analysis of voltammograms showed the presence of only one redox pair, with half wave potentials (E1 / 2) at 105, 334 and 242 mV for compounds NAT211, NAT212 and NAT213, respectively, indicative of the redox pair FeIII / FeII.

15
  • GIORGIO LÚCIO FERNANDES
  • Construction of a multichannel UV-VIS spectrophotometer and applications in the study of chemical reaction kinetics: a proposal for an analytical and educational platform

  • Advisor : POLLYANA SOUZA CASTRO
  • COMMITTEE MEMBERS :
  • WAGNER BEZERRA
  • FERNANDO SILVA LOPES
  • POLLYANA SOUZA CASTRO
  • VALTER JOSE FERNANDES JUNIOR
  • Data: Aug 11, 2021


  • Show Abstract
  •  

    The UV-VIS spectrophotometer is the most widely used analytical instrument in analytical laboratories around the world. Due to the recurrent lack of investment in Brazilian education, it is still possible to observe a great lack of infrastructure in teaching laboratories. As an alternative to the acquisition of these commercial equipment, the present work presents the construction and validation of a portable, low cost and light multichannel UV-VIS spectrophotometer. The instrument has the construction scheme of a single-beam spectrophotometer, using a CMOS (Complementary metal-oxide-semiconductor) camera as a multi-channel detector, a 1000 lines/mm holographic diffraction grating and a thermostated cell for the sample, innovative component compared to commercial instruments. The assembled device cost approximately $95.00, its dimensions were 23cmx13cmx06cm, providing easier accommodation and transport. For validation, a potassium permanganate solution was used as a chemical species due to its characteristic absorption spectrum. Thus, calibration tests and analytical validation of the equipment were performed by constructing an analytical curve with concentration solutions from 2.5x10-5 to 2.0x10-4 mol/L. As results, figures of merit were obtained: linear correlation coefficient (R2) 0.997, detection limit 0.331 mg/L, quantification limit 1.10 mg/L, measurement dispersion of 1.7%, spectral resolution 0.14nm , acquisition speed of up to 120 spectra/s. In addition, the molar absorptivity for potassium permanganate of 2.554 x103 Lmol-1cm-1 was calculated, being consistent with values reported in the literature. The equipment was also used to monitor the kinetics of chemical reactions. The investigated reaction was the oxidation of sucrose by potassium permanganate in a basic medium, known as the “chemical chameleon”. From the results obtained, the linear behavior in the Arrhenius equation was observed between temperatures from 30°C to 40°C, calculating the kinetic parameters Ea=13,932.03 J; ∆H# (308.15K) = 11,370.07 J; ∆S# (308.15K) = -190.43 J; ∆G# (308.15K) = 70,052.13 J. Therefore, the manufactured equipment shows itself as a promising miniaturized analytical platform, accessible and with performance and performance comparable to commercial equipment, in addition to showing itself as a good teaching tool due to its ability to work fundamental concepts of chemistry.

     

16
  • JOADIR HUMBERTO DA SILVA JUNIOR
  • Synthesis, characterization, and spectroelectrochemicalstudy of polyaniline thin films

  • Advisor : POLLYANA SOUZA CASTRO
  • COMMITTEE MEMBERS :
  • POLLYANA SOUZA CASTRO
  • CARLOS ALBERTO MARTINEZ HUITLE
  • BRUNO CAMPOS JANEGITZ
  • RODRIGO ALEJANDRO ABARZA MUNOZ
  • Data: Aug 24, 2021


  • Show Abstract
  • A polianilina (PANI) é um homopolímero intrinsecamente condutor com interessantes propriedades eletroquímicas e espectroscópicas. Característica da sua natureza macromolecular, esse material pode apresentar propriedades diversas de acordo com a forma como é obtido e/ou processado.Neste trabalho, filmes finos destepolímero foram sintetizados sobre eletrodos de platina por meio de processos eletroquímicos distintos. Ascaracterísticas do material formadoforam investigadas a partir de estudos espectroeletroquímicos in situ usando técnicas espectroscópicas eletrônicas (UV-VIS) e vibracionais (Raman). Além disso, análises complementares utilizando espectroscopia no infravermelho (IRRAS), voltametria cíclica e difraçãode Raios-X também foram utilizadas para caracterização do material. As análises in situforam possíveis graças ao desenvolvimento de células espectroeletroquímicas usando a tecnologia de impressão 3D por fusão e deposição de material (FDM). A competência das célulasfabricadas foi avaliada a partir de materiais e processos com comportamento espectroscópico e eletroquímico previsível e amplamente descritosna literatura. O corante vermelho allura AC e o crescimento e conversão eletroquímica de filmes finos de Azul da Prússia foram investigados obtendoboa consonânciadosresultados, validando portanto a utilização das células espectroeletroquímicas. As características eletroquímicas dos filmes de polianlina sintetizados divergiram de acordo com o método de síntese, e à causa foi atribuída fator conformacional das cadeias poliméricas, que se moldam a partir de mecanismos distintos e característicos de cada meio de obtenção. Os resultados sugerem que filmes obtidos galvanostaticamente apresentam maior organização das cadeias e maior resistência ao transporte de prótons durante processos de interconversão eletroquimicamente induzidos.

17
  • LUCAS HILÁRIO NOGUEIRA DE SOUSA
  • Literature review on the genus Callyspongia and chemical analysis of the species Callyspongia vaginalis.

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • NILCE VIANA GRAMOSA POMPEU DE SOUSA BRASIL
  • LEANDRO DE SANTIS FERREIRA
  • RENATA MENDONÇA ARAUJO
  • Data: Sep 17, 2021


  • Show Abstract
  • The genus Callyspongia (Callyspongiidae) is a group of demosponges including 261 described species and approximately 180 accepted by taxonomist’s review. The marine organisms of Callyspongia are distributed in tropical ecosystems, especially in the central and western Pacific, but also in the regions of the Indian, the West Atlantic and the East Pacific Oceans. The interest in the genus Callyspongia is because it is a source of bioactive compounds. In this review, we group the chemical information about the secondary metabolites isolated from the genus Callyspongia, as well as studies of the biological activity of these compounds. Through NMR data, a total of 212 metabolites were identified from genus Callyspongia (15 species and Callyspongia sp.), of which 103 compounds are categorized as polyacetylenes and lipids. Beside these, benzenoids, alkaloids, indol derivatives, diazepine, diketopiperazines, dipeptides, amphiphilic diacid, naphthopyrone, macrolide, polyketides, dihydrofurans, benzofuran, nucleosides, cyclic peptides, cyclic depsipeptides were isolated in the genus. 109 molecules have been reported with some bioactive activity, mainly cytotoxic and antimicrobial (antibacterial and antifungal) action. Thus, we conclude that polyacetylenes correspond to the largest class of bioactive metabolites of the genus and the results are in accordance with the relevance of the metabolites for anticancer action. In addition, a chemical prospection of the hexane fraction from ethanol extract of the specie Callyspongia vaginalis carried out in the present paper allowed the isolation and identification by spectroscopic analysis techniques, including 1D and 2D NMR, of two substances: β-sitosterol, widely isolated in plants, but reported one time in genus, and a ceramide, reported here for the first time in the genus Callyspongia. In addition, GC-MS analysis allowed the identification of four unsaponifiable compounds (stigmasterol, brassicasterol

18
  • IGOR RAFAEL RESENDE DE OLIVEIRA
  • In Silico Investigation of Stigmurin Analog Antimicrobial Peptides with Membrane Models

  • Advisor : DAVI SERRADELLA VIEIRA
  • COMMITTEE MEMBERS :
  • CARLOS ALESSANDRO FUZO
  • ANDERSON DOS REIS ALBUQUERQUE
  • DAVI SERRADELLA VIEIRA
  • Data: Sep 23, 2021


  • Show Abstract
  • Stigmurin (Stig), a peptide originating from the venom of the scorpion Tityus stigmurus, and its analogs (StigA8, StigA15, StigA18, and StigA28), are effective in previous in-vitro and in-vivo studies (Larvae of Mariposa Galleria Mellonella), with Stig showing antibacterial activity on Gram-positive bacteria and the analogs on both Gram-positive and Gram-negative. To investigate in detail the interaction of these peptides with different bacterial membranes and establish structural parameters to discuss the mechanism of action of these peptides, molecular dynamics (MD) simulations of Stig, StigA8, and StigA18 peptides were performed in Gram-positive membrane and Gram-negative membrane models. Systems with 1, 2, and 7 peptides were simulated to investigate the effect of peptide concentration on membrane disturbance. MD simulations were carried out using Gromacs 2018 software package and the perturbation and stability analyzes were performed with MEMPLUG (Membrane Thickness, Area by Lipid and Order Parameter). The intermolecular interaction energies were calculated as a function of the time between each peptide and the membrane, showing that there is a greater stabilization in the interactions of the analog peptides with bacterial membranes compared to Stig. Structural parameters, such as membrane fluidity and lipid area, were also evaluated. Analogous peptides caused greater disorder in the lipid tail of bacterial membranes than Stig, characterizing the greater perturbation effect caused by the analogs. Bacterial membranes underwent a slight increase in their surface area, due to the surface interaction and coupling to the membrane surface by the peptides. Finally, the simulations for the concentrated systems (7 peptides) showed the formation of the aggregates, and consequently, a greater local disturbance on the membranes, with drastic reductions in their thickness at the interaction region. The present work corroborates the experimental results and suggests that the mechanism of action of these peptides must be investigated by longer simulations, in concentrations that favor the formation of the aggregates.

19
  • ANTÔNIO MARCELO SILVA LOPES
  •  In situ synthesis of highly stable carbon-encapsulated FeCo alloy from ethanol

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • TIAGO PINHEIRO BRAGA
  • MARCO ANTONIO MORALES TORRES
  • JOSÉ MARCOS SASAKI
  • Data: Oct 26, 2021


  • Show Abstract
  • This research proposed to develop a FeCo magnetic alloy encapsulated in carbon, using ethanol as a carbon precursor, through the CVD route, for the photocatalytic degradation of organic contaminants. Initially, a CoxFeyO4 oxide in a 1:1 ratio was synthesized using the Pechini method. The material was subjected to in situ reduction, by the CVD method, using ethanol as the initial reagent at temperatures of 400, 500, 600 and 700ºC. The reactions were studied by Gas Chromatography (GC), from gas aliquots collected at predetermined times. From the ethanol dehydrogenation and dehydration reactions, it is transformed into an encapsulated binder and, for comparative purposes, it is reduced to oxide in the pure FeCo binder using only H2. You are materialized by a characterized and interpreted result. From the analysis of XRD and Rietveld Refinement, it is possible to identify the phases present without CoxFeyO4 oxide, as well as the presence of crystalline carbon and FeCo phases in reduced materials via CVD, whose peak intensity increases with the synthesis temperature. Thus, we show FeCo-400 and FeCo-700 were treated in acidic and alkaline medium and we verified the importance of encapsulation for the stability of the FeCo bond. TGA profiles indicate an increase in the thermal stability of the bond as the local temperature is raised. Magnetic measurements performed for the FeCo, FeCo-400 and FeCo-700 samples reveal a reduction in the more values due to the presence of the carbon phase, as well as showing high Hc values compared to the FeCo Bond, especially for an It presents FeCo-400, which may be associated with the existence of a fraction of the oxide phase that was not reduced. Mössbauer spectroscopy confirms the presence of the BCC structure of the FeCo magnetic bond in FeCo, FeCo-400 and FeCo-700 materials and indicates values of isomeric displacement and Bhf coefficient with literature for the FeCo phase. The H2-TPR profile shows a complete reduction of the oxide in the bond at approximately 470°C, or which justifies the presence of the mixture of oxide and bonding phases in presenting FeCo-400. The profiles of NH3-TPD and CO2-TPD revealed the presence of Lewis acid sites and basic sites (O2-). The Raman spectra will show that a higher and lower degree of graphitization is respectively FeCo-700 and FeCo-500, which uses TEM analysis to confirm the presence of more organized CNTs for FeCo-700. The SEM-FEG analysis shows the uniformity of the oxide surface and the prediction of the presence of CNTs, which was confirmed by the TEM images. Adsorption tests prove or encapsulate two materials as the synthesis temperature increases and indicate a less encapsulated FeCo-400 that synergizes with Fe-Co oxide as an adsorbent. Proposal is a mechanism to explain the formation of carbon-based encapsulated binding material in ethanol dehydration and dehydration reactions. The band-gap energy of two materials indicates that they are promising for photocatalytic applications, where the photodegradation of methylene blue (MB) is studied, which obtains the best removal for the FeCo-400 sample through a photo-processing process. Fenton with in situ H2Ogeneration, which also has its mechanism of synergism between the encapsulated bond and the oxide phase, together with the small diameter of the crystallite of the FeCo bond, favors MB photodegradation.

20
  • ROALLISSON SPAYCK DE OLIVEIRA SILVA
  • ELECTROCHEMICAL DETECTION OF CAFFEINE USING A BORON DOPED CARBON NANOWALL ELECTRODE (B: CNW)

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • ELISAMA VIEIRA DOS SANTOS
  • DANYELLE MEDEIROS DE ARAUJO
  • Data: Oct 29, 2021


  • Show Abstract
  • Over the years there have been significant increases in the production and consumption of caffeine worldwide, this popularity is due to its important physiological effects, however, its unregulated use and inadequate dosages can cause serious problems in the short and long term. Taking great interest and concern from the scientific community in studying and proposing new effective ways to monitor the dosage used for the production of products containing caffeine. Electrochemical techniques suggest a new and efficient way to detect caffeine quickly. Using simple instrumentation, they provide an efficient detection sensitivity for the compound of interest. The present work will address the use of a new boron-doped carbon nanowall electrode (B: CNW) for the detection of caffeine. Electrochemical studies were performed on synthetic and real samples, the results showed that the new electrode presented an anodic signal for caffeine in the range of 1.35 V, the analysis of the regression residues showed that there is a linear response, obtaining a limit detection of 7.97 x 10-5 M. The electrode was able to efficiently quantify low concentrations of caffeine present in real samples of commercial products. The results and previous studies carried out so far, demonstrate the potential of this modified electrode for future applications in food sensors, but further study and improvement in experimental parameters is required for its use as a chemical and biological sensor.

21
  • CARLOS VITAL DOS SANTOS JÚNIOR
  • Electronic structure and chemical bonds in mechanisms of chemical reactions of nucleophilic substitution: Topological analyses of total and overlap electronic density

  • Advisor : MIGUEL ANGELO FONSECA DE SOUZA
  • COMMITTEE MEMBERS :
  • ANDERSON DOS REIS ALBUQUERQUE
  • JÚLIO COSME SANTOS DA SILVA
  • MIGUEL ANGELO FONSECA DE SOUZA
  • RENALDO TENÓRIO DE MOURA JÚNIOR
  • Data: Oct 29, 2021


  • Show Abstract
  • Understanding the key aspects of chemical reaction mechanisms is usually focused on the profile energetic surface (PES) energetic and structural. However, bond analysis methodologies can add information about the reaction mechanisms. An attractive reaction to apply bond analysis methods is the bimolecular nucleophilic substitution (SN2). A peculiar feature of this reaction in the gas phase is the PES dependence on the atomic center and/or substituent group nature, generally attributed to steric effects. The central goal of this work is to apply the QTAIM, overlap properties (OP), and local vibrational mode (LVM) theory models to study the chemical bonds in stationary points of the Cl + XR3Cl (with A = C and Si) and C–– + BR2Cl (with B = P and N) reactions, with R = H, F, Cl, Me, e Et. On the one hand, for the SN2@C and SN2@N reactions, the reactants and products are separated by a pentacoordinate(@C) and tetracoordinate (@N) transition state (TS), corresponding to a saddle point in the PES. On the other hand, for SN2@Si and SN2@P reactions a stable pentacoordinate(@Si) and tetracoordinate (@P) transition complex is observed. The chemical bond descriptors  and , overlap properties () and LVM force constants () were obtained for the studied systems. QTAIM analysis indicated that the C–R and N–R bonds are indicated to be more covalent than the Si–R and P–R bonds, due more negative HBCP and  values. These results agree with the overlap properties to C–R and N–R bonds, indicating a high density concentration as compared to Si–R and P-R bonds. Besides, the LVM analysis also reveal that the C–R and N–R bonds are more stronger (from the force constants  values) than Si–R and P–R ones. Lastly, the overlap Coulomb repulsion energy () is generally greater in C–R than in Si–R in XR3Cl systems, suggesting that the steric hindrance experienced by Cl in SN2@C reactions is probably associated with the greater covalent nature of C–R bonds, that concentrate density along the chemical bond more efficiently than in Si–R.

     

22
  • DANIEL LUCAS DANTAS DE FREITAS
  • : Development of graphical interface based on exploratory analysis for multivariate chemical data

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • KASSIO MICHELL GOMES DE LIMA
  • LUCIENE DA SILVA SANTOS
  • EDGAR PERIN MORAES
  • Cristina Malegori
  • Data: Dec 16, 2021


  • Show Abstract
  • This dissertation aims to demonstrate application of supervised and exploratory classification algorithms in chemical data, showing the potential of this combination. For this, three research articles are available. Initially, two applications based on infrared spectroscopy and supervised classification are addressed. Finally, a computational tool based on exploratory analysis is proposed as a technological innovation for data analysis. The first article consists of the application of chemometric tools as na alternative method of screening for breast cancer, aiming at rapid, low-cost, minimally invasive and statistically reliable detection when compared to the mammography method, which is now established as the standard method for screening and detection. The second article demonstrates the application of spectroscopic and supervised classification methods in HIV-infected patients, aiming at their rapid detection through blood plasma at a low operating cost. The third article presents a graphical user interface (GUI) built as a user-friendly, iterative, educational and scientific tool with a strong visual appeal. This interface uses several clustering methods, based on hierarchical group analysis (HCA), as well as principal component analysis (PCA) for exploratory data study, focusing on first-order spectroscopic data. Furthermore, the interface can be used for data processing and cluster estimation, presenting itself as a potential tool for multivariate chemical data analysis. The results presented here are useful and innovative, serving as theoretical and practical support for future chemometric applications.

23
  • WELLINGTON JEFFERSON OLIVEIRA DA SILVA
  • PHYSICAL-CHEMICAL EVALUATION OF AERONAUTICAL FUEL: AN APPROACH TO STABILITY AFTER STORAGE AND ADDING ADULTERANTS

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • LEILA MARIA AGUILERA CAMPOS
  • LUCIENE DA SILVA SANTOS
  • TATIANA DE CAMPOS BICUDO
  • Data: Dec 27, 2021


  • Show Abstract
  • O querosene de aviação, principal combustível aeronáutico, devido a demanda de utilização e por questões de segurança, necessita de um criterioso controle de suas propriedades físico-químicas, que infiram a qualidade do produto. Entretanto, processos de adulteração nas etapas de distribuição e abastecimento, podem comprometer a qualidade deste produto. Neste trabalho, foi desenvolvida metodologia para a simulação e detecção do processo de adulteração do querosene de aviação, QAV, com a adição indevida de um querosene iluminante (50%, v/v), de baixo custo, com a finalidade de evidenciar este grave problema mundial. Análises físico-químicas especificadas pela Agência Nacional de Petróleo, Gás Natural e Biocombustíveis - ANP, não foram capazes de identificar a adulteração das amostras. Visando identificar e quantificar o adulterante no QAV, além de avaliar o efeito causado pelo envelhecimento das amostras, foram desenvolvidas metodologias baseadas em modelos quimiométricos, PCA, PCA-LDA e MCR-ALS utilizando as espectroscopias de infravermelho, MIR e NIR. Aplicando estes modelos, a adulteração do QAV com o querosene comercial, na faixa de 5 a 60% (v/v), foi avaliada em intervalos semanais, num período de 0 a 60 dias. Os modelos de classificação separaram as amostras em duas classes, antes e após 30 dias, com boa precisão. A presença de bandas que representam a oxidação dos compostos presentes nas amostras adulteradas, como as de fenóis e ácidos carboxílicos, foi determinante na identificação do aging. Foram obtidos 100 % de sensibilidade e especificidade para o PCA-LDA. MCR-ALS conseguiu identificar os perfis espectrais dos componentes nas amostras, gerando um excelente método para a identificação do adulterante no QAV.

24
  • PAULO VITOR MATIAS FARIA
  • Computational Modeling of the Reaction of the Pyrrolidine with Pyridine-N-Oxide Activated by Phosphonium Salt: Electrostatic Control Of Regioselectivity.

  • Advisor : MIGUEL ANGELO FONSECA DE SOUZA
  • COMMITTEE MEMBERS :
  • MIGUEL ANGELO FONSECA DE SOUZA
  • FABRICIO GAVA MENEZES
  • ELIZETE VENTURA DO MONTE
  • Data: Dec 29, 2021


  • Show Abstract
  • Aminopyridines belong to an important class of compounds in organic chemistry, due to their applications in the construction of drugs particularly related to neurological diseases. In 2010 an alternative, general, easy and one-pot method was presented for the synthesis of 2-aminopyridines from pyridine-N-oxides activated with phosphonium salts. This alternative method showed high efficiency and selectivity when compared to the conventional preparation method. In this work, the mechanism of this synthesis was elucidated through quantum calculations of electronic structure, using the density functional theory and the continuous solvation model. We are proposing that the mechanism of this reaction be described in four steps and that the regioselectivity be kinetically controlled, but not thermodynamically. First, the pyridine-N-oxide is added to the phosphonium salt from a nucleophilic displacement, forming a first reaction intermediate (a phosphonium complex with a double positive charge). Second, this first intermediate undergoes an amine attack, which can occur either at position 2 or at position 4 of the activated pyridine-N-oxide. Finally, two subsequent proton abstractions must produce 2- and/or 4-aminopyridines. Our computational results suggest that counterions, which are derived from the phosphonium salt, play a key role in the regioselectivity of these reactions. We found that 4-aminopyridine formation is slightly favorable when the reaction path is modeled without the presence of counterions. However, when counterions were considered in the reaction mechanism, we observed that the pathway related to the attack at position 2 of pyridine-N-oxide becomes preferential, presenting more accessible reaction barriers and exergonic reaction intermediates. The regiochemical preference for the addition of the 2-position can be attributed to a charge association that occurs between the reactional intermediate of the phosphonium complex and the counterions. Furthermore, we verified a critical dependence of the evolution of this reaction with some characteristics of the phosphonic additive. In this case, the phosphonium salt must have a good leaving group for the pyridine-N-oxide activation step to occur easily.

Thesis
1
  • JOSÉ EUDES LIMA SANTOS
  • STUDY OF THE EFFICIENCY OF CATHODIC PRODUCTION OF H2 FROM THE ADVANCED ELECTROCHEMICAL OXIDATION OF RED METHYL AND SODIUM 2,4-DICLOROPHENOXYACETATE POLLUTANTS

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DAYANNE CHIANCA DE MOURA
  • MARCO ANTONIO QUIROZ ALFARO
  • NEDJA SUELY FERNANDES
  • POLLYANA SOUZA CASTRO
  • SUELY SOUZA LEAL DE CASTRO
  • Data: Jan 19, 2021


  • Show Abstract
  • Environmental pollution, especially of water, and the energy crisis caused by the growing use of fossil fuels are two of the greatest contemporary world problems that require an immediate solution. For this reason, this work proposed to evaluate the efficiency of hydrogen production from the oxidation of two of the most polluting sources of water, dyes and herbicides. For this purpose, the electrochemical oxidation of the methyl red dye (MR) and the herbicide 2,4-dichlorophenoxyacetate (2,4-DNa) was investigated in the anodes of Si/BDD, Pb/PbO2 and Ti/Sb doped SnO2 in acidic aqueous medium by applying 30 mA cm-2 with simultaneous production and quantification of the hydrogen gas produced in the cathode bay. The electrochemical experiments were performed in an electrochemical cell of two compartments separated by a Nafion® membrane. The electrochemical degradation process was monitored by UV-VIS spectroscopy, HPLC and Total Organic Carbon analysis. The electrocatalytic properties of anodes and cathodes were evaluated by Tafel parameters obtained by linear sweep voltammetry. The results clearly showed that MR and 2,4-DNa can be oxidized over such anodes, but both the oxidation level and anodic current efficiency varied significantly between these materials. Si/BDD had the highest electrochemical removal capacity of organic pollutants, which was attributed to the high participation of hydroxyl and sulphate radicals. The formation of the sulfate radical, only in the anode of BDD, inhibited the production of oxygen in the anode by about 50% in 0.5 mol L-1 of H2SO4. Regarding hydrogen production, the results showed that the H2 production rate is dependent on the current applied, the electrolysis time and the cell design. Moreover, the cathodic current efficiency was higher than 80% in the type H cell and 100% in the type II cell. The use of alternative cathodic materials to platinum has efficiencies similar to this noble metal, differing only in its chemical/electrochemical stability in the electrolytic medium studied and in the overpotential of hydrogen. With hydrogen production, the energy consumption of the electrochemical system can be reduced by up to 44% with the BDD anode supported on niobium and platinum cathode on 2 mol L-1 of H2SO4. Therefore, with this coupled system it is possible to reduce the impact of water pollution and generate a clean energy source that can be used to reduce the cost of electrochemical water treatment processes.

2
  • JOSÉ ANDERSON MACHADO OLIVEIRA
  • CHARACTERIZATION OF THE COMPOSITE COATINGS OF CHITOSAN-TUNGSTEN AND CHITOSAN-MOLYBDENUM OBTAINED BY ELECTROPHORETIC DEPOSITION.  

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • ANA REGINA NASCIMENTO CAMPOS
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • JOSE LUIS CARDOZO FONSECA
  • MARCIA RODRIGUES PEREIRA
  • POLLYANA SOUZA CASTRO
  • RENATO ALEXANDRE COSTA DE SANTANA
  • Data: Jan 21, 2021


  • Show Abstract
  • Chitosan is a naturally occurring polysaccharide derived from chitin. It has biocompatible, antibacterial, biodegradable properties, low toxicity, and excellent film formation capacity. Therefore, chitosan-based composite materials or coatings can be applied in different technological and industrial sectors, for example, in the food, cosmetics, textile, biomedicine, and agriculture industries. Due to their mechanical properties and corrosion resistance, tungsten, molybdenum, and their compounds can be used to produce materials with superior properties for applications in environments under extreme operational requirements. Thus, based on the intrinsic properties of chitosan and the metals tungsten and molybdenum, two new composite coatings of chitosan-tungsten (Quit-W) and chitosan-molybdenum (Quit-Mo), obtained by the electrophoretic deposition process, were characterized in this work to evaluate its possible application for protection of metallic structures against corrosion in a medium containing chloride ions (NaCl). The results of morphology (SEM), chemical composition (EDS), crystallography (XRD), and spectroscopy in the infrared region (FT-IR) confirmed the deposition of composite coatings consisting of a film on the micrometric scale, impregnated with metal nanoparticles (tungsten or molybdenum) distributed homogeneously in the chitosan matrix. The results of corrosion resistance, obtained by Potentiodynamic Polarization (PP) and Electrochemical Impedance Spectroscopy (EIS), showed that the composite coatings improved the corrosion resistance of 1020 steel exposed in corrosive NaCl medium (3.5 %). The Quit-W composite coating obtained under the operating conditions of 10 V, pH 5.5, and 10 minutes of deposition showed a corrosion current density (icorr) of 4.0 ± 0.2 µA/cm²; the Quit-Mo composite coating obtained in the conditions of 5 V, pH 5.5, and 10 minutes of deposition (suspension 1: 0.5 g/L of chitosan and 1 mmol/L of sodium molybdate) showed an icorr of 1.4 ± 0.3 µA/cm², thus being the most corrosion-resistant coatings for each evaluated system. Therefore, the results presented here prove the achievement of a new class of chitosan-based composite materials with potential application for the protection of metallic structures against corrosion.

3
  • PAULO CÉSAR FRANÇA DA CÂMARA
  • Obtaining biomaterials using tannin derivatives and glycosaminoglycans for applications in tissue engineering and regenerative medicine

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • CARLOS AUGUSTO GALVAO BARBOZA
  • DENISE FREITAS SIQUEIRA PETRI
  • JOSE LUIS CARDOZO FONSECA
  • JULIANA DE SOUZA NUNES
  • PAULO NORONHA LISBOA FILHO
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Feb 2, 2021


  • Show Abstract
  • Develop stable polysaccharide structures with biochemical and biomechanical properties used by extracellular matrix (ECM) is one of the goals of tissue engineering and regenerative medicine. Improve the biocompatibility of conventional materials through surface modification has been shown to be an effective way to enhance their biological response. In addition, biomaterials used in medical devices need to be compatible with various biological environments, not activating the patient's immune system, leading to rejection and failure of these materials. We report a new class of surface coatings for the purpose of enhancing biocompatibility and cellular response using multilayer self-assembled polyelectrolytes (PEMs) with a derivative of cationic tannins and glycosaminoglycans (chondroitin sulfate or heparin) because they exhibit similar chemical structures to found in ECM. The construction of polyelectrolyte multilayers was monitored by Fourier Transform Surface Plasmon Resonance (FT-SPR). The surface properties were assessed by X-ray Excited Photoelectron Spectroscopy (XPS), Atomic Force Spectroscopy (AFM) and contact angle measurements. The response of human adipose-derived stem cells (ADSCs) was evaluated in vitro through cytocompatibility assays, adhesion and proliferation of the cells using fluorescence microscopy. For the hemocompatibility assays, the adsorption of serum protein, adhesion and platelet activation, as well as whole blood coagulation assays was monitored by XPS, scanning electron microscopy (SEM) and visible ultraviolet (UV-vis) spectroscopy. The interactions of ADSCs with these new biomaterial surfaces demonstrate that these surface coatings exhibit good cytocompatibility and that they promote cell attachment and proliferation. Blood tests point to the high potential of developing hemocompatible materials through tannin derivatives. Particularities in the chemical structure of tanfloc were signaled as crucial in the control of blood protein adsorption, such as fibrinogen, creating an antiplatelet effect on the surface of the materials. The association between biomaterial components and cells and key bioactive molecules in biological processes important in the reconstruction of large tissue losses highlights the great potential of materials. These characteristics are very desirable for biocompatible coatings for applications such as tissue engineering scaffolds and medical devices.

     

4
  • STÉPHANIE CAVALCANTE DE MORAIS
  • Evaluation of polyelectrolytic complexes based on poly(epichlorohydrin-co-dimethylamine) and poly (4-styrene-sulfonic acid-co-maleic acid) in the delivery of polyphosphates for the control of CaCO3 scale in oil wells

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ROSANGELA DE CARVALHO BALABAN
  • JOSE LUIS CARDOZO FONSECA
  • MIGUEL ANGELO FONSECA DE SOUZA
  • ALESSANDRO FRANCISCO MARTINS
  • MARCOS ANTONIO VILLETTI
  • Data: Mar 11, 2021


  • Show Abstract
  • Polyelectrolytic complexes (PEC) based on poly(epichlorohydrin-co-dimethylamine) (EPI-DMA) and poly(4-styrene-sulfonic acid-co-maleic acid) (PSSMA) for polyphosphate encapsulation were first prepared in the literature. The PEC was developed in order to increase the durability of the treatment of scale in oil wells. Sodium hexametaphosphate (SHMP) was used as a model polyphosphate in this work and evaluated as a calcium carbonate scale inhibitor. The relationship between pH and CaCO3 formation was evaluated by static tests, dynamic precipitation in capillary and scanning electron microscopy (SEM) images. At pH 6.5, excellent results were found with complete inhibition of CaCO3 deposition in the capillary with only 2.5 mg L-1 of SHMP and a deformed structure of the CaCO3 crystals by SEM images was observed. In turn, at pH 7.5 and above, SHMP showed a significant decrease in the efficiency of scaling inhibition even at high concentrations. These results were attributed to the precipitation kinetics of CaCO3 under the drastic conditions evaluated. To optimize the PEC formulations, a 23 factorial design was applied. The resulting PEC suspensions were characterized by dynamic light scattering (DLS), zeta potential and SHMP encapsulation efficiency (EE). The best results were found by the formulation using 1% (w/w) of EPI-DMA, 0.1% of PSSMA and addition of SHMP before PSSMA. This optimized formulation was applied in real oil well conditions and showed good stability at 25 °C and reduced stability with increasing temperature. The PEC showed excellent inhibition efficiency against calcium carbonate scale with minimum effective concentration (MCE) of 2.0 mg L-1 using the same concentration of SHMP at 100 °C and 1000 psi. The PEC suspension also showed exceptional performance in the evaluation of the interaction with sandstone, improving not only the adsorption of the material in the rock grains, but also the durability of the treatment by 100%.

     

5
  • ARGEU CAVALCANTE FERNANDES
  • APPLICATION OF ADVANCED OXIDATIVE ELECTROCHEMICAL PROCESSES (AOEP’s) IN THE TREATMENT OF PHARMACEUTICAL EFFLUENTS USING DDB ANODE

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • ALINE MARIA SALES SOLANO
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • DJALMA RIBEIRO DA SILVA
  • ELISAMA VIEIRA DOS SANTOS
  • Data: May 19, 2021


  • Show Abstract
  • In this study, the Anodic Oxidation processes with in situ hydrogen peroxide (AO-H2O2) and Electro-Fenton (EF) processes were used for the decontamination of two synthetic effluents containing the drugs caffeine and metformin hydrochloride (MET). the first one of the compounds most consumed by the general population and the last used in the treatment of type II diabetes. The anode using was the DDB boron doped diamond. The efficiency of the processes was evaluated by means of spectroscopy in UV-vis, COD, COT and HPLC. In order to optimize the processes, the influence of operational parameters was studied, such as support electrolyte concentration, drug concentration, current density (15, 30 and 60 mA cm-2) and initial pH (3.0). The maximum removal of caffeine, due to the chemical oxygen demand (COD), reached 92% and 53% after 360 min of electrolysis at the initial pH 3 for EF and AO-H2O2, respectively, with the initial concentration of caffeine 100 mg L-1, with a constant current density of 30mA cm-2 and 0.05 mol.L-1 of the Na2SO4 electrolyte. As for MET, it was possible to notice that the increase in the applied current density also favored the removal using AO-H2O2. Observing the EF data, it was possible to notice that the results were better with more than 97% removal when compared to AO-H2O2, which achieved 85% removal.

6
  • MAICON OLIVEIRA MIRANDA
  • PHOTOCATALYTIC DEGRADATION OF IBUPROFEN USING TITANIUM NANOPARTICLES SUPPORTED ON CMK-3 MESOPOROSUS CARBON.

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • ANNE GABRIELLA DIAS SANTOS
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DAVI SERRADELLA VIEIRA
  • EDSON CAVALCANTI DA SILVA FILHO
  • TIAGO PINHEIRO BRAGA
  • Data: Jul 22, 2021


  • Show Abstract
  • TiO2 nanoparticles dispersed in ordered mesoporous CMK-3 carbon with different Ti contents were successfully synthesized and their activity in the photocatalytic degradation of ibuprofen was presented. The photocatalysts were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, diffuse reflectance, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM-FEG) and transmission electron microscopy (TEM). A simple theoretical-computational study through the single point energy calculation was also presented. Diffractograms, Raman, and XPS spectra confirmed the formation of anatase and graphitic carbon. Low-angle XRD, N2 physisorption and the TEM images indicated that the CMK-3 support does not undergo a significant change in the mesoporous structure after the insertion of TiO2. The ID/IG ratio observed in the Raman spectra did not vary significantly with an increase in the titanium content, which shows that the crystallinity of CMK-3 is practically unchanged. Anatase crystallite sizes vary from 8 to 15 nm and specific areas vary from 348 to 586 m2.g-1, depending on the TiO2 content. The single point energy calculation confirmed the lowest energy to stabilize the titanium oxide and carbon composite for the sample with 1% of Ti compared to 8 and 18%. The 1% TiO2/CMK-3 photocatalyst exhibited the best photocatalytic performance, reaching 100% degradation in just 5 min. Chemical oxygen demand and total organic carbon results confirmed the mineralization of ibuprofen. The degradation and mineralization mechanism of ibuprofen follows a sequence of radical reactions that occur in solution and on the solid surface, and may lead to the formation of intermediates before its mineralization.

7
  • DAMIANA SINÉZIO DE SOUZA
  • Controlled insertion of aluminum oxide pillars in bentonite clays

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • FABIO GARCIA PENHA
  • FERNANDO JOSÉ VOLPI EUSÉBIO DE OLIVEIRA
  • LINDIANE BIESEKI
  • Manuel Karim Sapag
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: Aug 6, 2021


  • Show Abstract
  • Clays are minerals widely available in nature. They are applied as catalysts in various chemical processes, such as oil cracking, and chemical transformations in soils. Some specific clays (such as bentonitic) have characteristics that allow us to modify their properties, such as an increase in specific area, an increase in active sites and greater thermal stability. Among the chemical modification processes of clays, there is pillarization, which consists of inserting pillars between the lamellae, increasing the basal spacing and consequently the accessibility of the clay galleries, thus intensifying its adsorptive and catalytic characteristics. A system for the synthesis of pillarization with Al30 was studied, which made it possible to obtain a material with properties superior to those synthesized using traditional methods. Variations were made in the parameters: Application of clay expansion with water, cetyltrimethylammonium bromide (CTMA-OH), tetrapropylammonium bromide (TPA-OH), ethylene glycol (EG), temperature, time, and concentration of reagents. The synthesis temperature of the pillaring solution as well as the heating time together show to be the primary factor in relation to the size of the basal spacings. The concentration of reagents also contributed to obtain Al30. The best results were obtained for the pillaring solution with ratio [OH]/[Al] = 2.4, temperature of 95°C for 12h. The results showed that it is possible to obtain some control over the insertion and size of columns in pillars with bentonite clays by adjusting the parameters of the synthesis system commonly used for pillars with Al13.

8
  • FLORYMAR ESCALONA DURÁN
  • Treatment of residual gaseous emissions by electro-absorbent technologies.

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • ENGRACIA LACASA FERNÁNDEZ
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • GIANCARLO RICHARD SALAZAR BANDA
  • MANUEL ANDRES RODRIGO RODRIGO
  • Data: Aug 24, 2021
    Ata de defesa assinada:


  • Show Abstract
  • In the search for new alternatives for the treatment of volatile organic compounds (VOCs) and gases with an unpleasant odor, in this work, the degradation of gaseous pollutants using electrochemically assisted absorbent devices was studied. For this, a packed column or a Venturi injector was integrated into an electrochemical cell (with boron-doped diamond anodes (BDD) supported on Tantalum and/or Silicon substrates) and the efficiency in the removal of toluene and perchloroethylene (PCE) from air streams was studied, without and with the mediating effect of the Co(II)/Co(III) couple in solution. In the first results, it was obtained that the formation of Co(III) on the Ta/BDD anode was significantly higher concerning the Si/BDD anode, which was later corroborated with the treatment of gaseous streams contaminated with PCE, where again the Ta/BDD anode was more efficient both in the production of Co(III) species and in the degradation of the pollutant, and the degradation rate increased in the presence of cobalt, especially when previous electrolysis was carried out for the accumulation of oxidants. Comparing the absorbent devices, it was obtained that the removal of PCE was more efficient using the Venturi injector both in absorption experiments and in electroabsorption. For its part, the removal of toluene by mediated electroabsorption yielded the best efficiencies, especially at high current densities; however, important participation of the sulfate/persulfate pair was also suggested in electroabsorption experiments with only an acidic medium as a supporting electrolyte. With the packed column, the system showed a better performance for the electrochemical degradation of toluene, while the Venturi injector reported the best efficiencies for the retention of the contaminant in the electrolyte/absorbent. The results obtained are interesting because, in general, both electroabsorption systems allowed the efficient removal of the treated pollutants. The BDD anode substrate seems to have a determining effect on the efficiency of the mediated electrochemical treatments, an aspect that has been little investigated and therefore offers a new line of study. Finally, the mediating effect of the Co(II)/Co(III) pair was significant in the treatment of PCE with pre-electrolysis and in the oxidation of toluene at the highest current density, in both cases using Si/BDD anodes, which highlights the relevance of mediated electro-oxidation mechanisms. The results obtained with the highest amounts of Co(III) generated at the Ta/BDD anode propose that the promotion of oxidants is not always positive from the point of view of their accumulation in the electrolyte, Ta/BDD anode appears to promote sufficient amounts of hydroxyl radicals, making the presence of the metal unnecessary.

    The high potential demonstrated so far by this integrated technology and the need to develop new gas treatment processes for real applications, suggest that electro-scrubbing technology may, in the long term, have important industrial applications in the treatment of numerous pollutants. gaseous.
9
  • SEMUEL EBENEZER DANTAS COSTA
  • synthetic rocks, petrophysical properties, uniaxial compressive strength, enhanced oil recovery.

  • Advisor : TEREZA NEUMA DE CASTRO DANTAS
  • COMMITTEE MEMBERS :
  • ANTONIO ROBSON GURGEL
  • EDNEY RAFAEL VIANA PINHEIRO GALVAO
  • JOSE LUIS CARDOZO FONSECA
  • MARCOS ALLYSON FELIPE RODRIGUES
  • TAMYRIS THAISE COSTA DE SOUZA
  • TEREZA NEUMA DE CASTRO DANTAS
  • Data: Aug 31, 2021


  • Show Abstract
  • : Due to modern society dependence on petroleum derivatives, researches about its exploration and production have become extremely important. Since the natural rocks commonly used in enhanced oil recovery (EOR) laboratorial trials are difficult to acquire and, also due to the fact that these rocks are usually anisotropic, the utilization of synthetic similar materials appear as an alternative to analysis and evaluation of EOR methods. Therefore, the present work aims to produce and evaluate synthetic rocks that may replace natural ones in EOR studies. To achieve that goal, rocks were created by mixing sand beach and ceramic, diatomaceous and kaolinite clays, using a 23 factorial experimental design and triplicate in the central point. During the making of the rocks, the binder concentration, compaction pressure and syntherization temperature were changed, in order to evaluate the petrophysical and mechanical characteristics of the synthetic rocks. The variance analysis (ANOVA) indicates that the porosity, permeability and uniaxial compressive strength models obtained are both predictive and significant, reaching determination coefficients of at least 0.95276. In addition, the petrophysical properties of the manufactured rocks presented similar values when compared to limestone and Berea and Botucatu sandstones, commonly used in EOR studies, with porosities from 17.89 to 36.78% and permeabilities from 14.34 to 201.98 mD. The best results were obtained with the ceramic clay, which contains a higher amount of funding minerals.

10
  • MAILON AGUIMAR DE LIMA
  • Cellulose nanocrystals obtaition from cotton waste and their potential application in oil well cement pastes

  • Advisor : JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • COMMITTEE MEMBERS :
  • ANDREZA KELLY COSTA NOBREGA
  • JOSE HERIBERTO OLIVEIRA DO NASCIMENTO
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • ULISSES TARGINO BEZERRA
  • Data: Sep 20, 2021


  • Show Abstract
  • Primary cementation consists in injection of cement into the annular space between the outer wall of the coating column and the rock formation. This process is extremely important in the oil and gas industry, aiming to fix the piping and prevent the migration of fluids between permeable zones. In its hardened state, it is extremely important to cement to be durable, providing a longer “life span” to the well. For this, 3 (three) characteristics are essential to the cement paste: porosity, permeability and compressive strength. Cellulose nanocrystals (CNC) has been widely applied as reinforcement material in cement and polymer matrices due to its unique properties such as: high crystallinity and contact surface, high Young modulus, high tensile strength and low thermal expansion coeficiente. For this reason, the aim of this research was to evaluate the influence of adding different concentrations of cellulose nanocrystals (0 to 0.3%) on mechanical strength of the cement (compressive strength), porosity and permeability. The nanocrystals were obtained from a cotton fiber residue arising from the sanding process, provided by the VICUNHA TÊXTIL® industry, Natal – RN. The obtention was carried out by acid hydrolysis (H2SO4  65% w/w), under constant agitation, for 60 minutes at 45ºC. The hydrolysis was stopped in an ice bath. The resulting suspension was subjected to 4 (four) centrifugation cycles of 15min at 11000rpm and 20ºC and then subjected to the dialysis process until reaching a pH close to 5-6. The stability of the resulting nanocrystal suspension was assessed by the zeta potential, in addition, the characterization of the CNC was made by transmission electron microscopy (MET), TGA, FTIR e XRD. The pastes were formulated based on the standards established by the API (American Petroleum Institute), with a volume of 600cm3  of paste and density of 15lb/gal. It was evaluated the concentrations of 0; 0.05; 0.1; 0.15; 0.2 and 0.3% of CNC in the compressive strength, porosity and permeability of the specimens. The results show that the resulting nanocrystal suspension was well dispersed, with needle-shaped nanocrystals (nanowhiskers) with a diameter and length of approximately 17 and 175nm respectively. The mechanical tests show a rapid gain in compressive strength (after 24 hours of curing), around 45% for the formulation containing 0.2% of CNC. Even after 28 days of curing, pastes reinforced with CNC still show better results when compared to the standard, with a gain greater than 30%, also for formulation 0,2%. The porosity and permeability tests show that even standard pastes (without the addition of CNC) have low permeability. Even so, the addition of nanocrystals reduced porosity by approximately 27% and paste permeability by 25% after adding any concentrations of CNC. The results indicatethat there is a great potential in the use of CNC to improve the mechanical strength of oil well cement, as well as reducing its porosity and permeability, thus enabling a more effective sealing of the annular space, preventing gas migration through the cement sheath and, consequently, improving well integrity.

11
  • JÚLIO CÉSAR OLIVEIRA DA SILVA
  • APPLICATION OF ELECTROCHEMICAL OXIDATION FOR TREATMENT OF REAL WASTEWATER IN PILOT PLANT

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • CARLOS ALBERTO MARTINEZ HUITLE
  • ELISAMA VIEIRA DOS SANTOS
  • ALINE MARIA SALES SOLANO
  • MARCO ANTONIO QUIROZ ALFARO
  • ÁMISON RICK LOPES DA SILVA
  • Data: Dec 3, 2021


  • Show Abstract
  • Water is the central axis for the sustainable development of countries, which must be consumed and disposed of conscientiously, but it is a limited resource, increasingly scarce in some regions of the world. Contamination of surface and underground water sources by organic chemical compounds is definitely a matter of concern. Lately, many technological alternatives for the treatment of wastewater and drinking water for human consumption have been proposed, among them the advanced oxidative processes (AOPs) have gained acceptance for the disinfection and decontamination of effluents. Treatments by advanced oxidative processes (AOPs) have shown good effectiveness in eliminating chemical and microbial contaminants in water. The main highlight of the (AOPs) is the in situ production of the highly reactive species, the hydroxyl radical (•OH), the superoxide radical (•O2-) and the sulfate radical (•SO4-) which can fragment organic pollutants and pathogens . These processes are based on electrogeneration of hydroxylic radicals (•OH), which can react non-selectively with organic pollutants until their complete removal. Radicals (•OH) have a high redox potential (2.8 eV/SHE) and are not selective, being able to attack organic compounds by four ways: hydrogen abstraction, combination or addition of radicals and electron transfer. In this work, a pilot plant and a reactor were built for the electrochemical treatment of anodic oxidation in wastewater from the petroleum industry, textile industries, pharmaceuticals and pesticides, disinfection of water with potability potential as a substitute for chlorine that can be a remediation alternative with low cost of assembly, installation and energy consumption, solar energy sources can be used. The results of this research clearly reveal that electrochemical oxidation - anodic oxidation used on a pilot plant scale is efficient and can be used in conjunction with other wastewater treatment techniques, as well as an alternative for disinfection of water with potability potential, without the use and storage of chlorine. The reactor proved to be efficient, and anodic electrodes of different materials can be applied according to the economic viability of the material. Like the reactor, the pilot plant can be used for other types of effluents, enabling further research and consequently increasing the variety of effluents that can be treated by the same equipment.

12
  • EDILSON DO VALE JÚNIOR
  • APPLICATION OF ELECTROCHEMICAL AND ELECTROANALYTICAL METHODS IN THE TREATMENT OF WASTEWATERS

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • ELISAMA VIEIRA DOS SANTOS
  • ALINE MARIA SALES SOLANO
  • DANYELLE MEDEIROS DE ARAUJO
  • MARCO ANTONIO QUIROZ ALFARO
  • Data: Dec 10, 2021


  • Show Abstract
  • The application of electrochemical technologies in remediation of wastewater has been extensively studied due to the promising results achieved. These technologies are mainly based on the generation of species with high oxidation power, which in turn are responsible for the degradation and mineralization of organic compounds. In this work, the application of some of these methodologies in the treatment of synthetic contaminated water was studied, in addition to the use of electroanalytical technologies in the detection and quantification of these compounds. The results achieved are presented in two distinct chapters. In the first chapter, peroxycoagulation (PC) was used to treat a synthetic effluent of methyl orange (MO), an azo dye, studying the effects of different parameters including initial pH, current density (j), initial concentration of dye and electrolyte support. In addition, PC performance has been compared to other advanced electrochemical processes, under similar experimental conditions. The results indicate that the kinetic decay of the MO increases in the following order: electrocoagulation (EC) < electrochemical oxidation (EO) with electrogenerated H2O2 < PC < electro-Fenton (EF). This behavior is attributed to the highly oxidizing character of the homogeneous ●OH radicals generated by the EF and PC processes. Energy consumption was about 0.06 kWh gCOD-1, 0.09 kWh gCOD-1, 0.7 kWh gCOD-1 and 0.1 kWh gCOD-1 were achieved for PC, EF, EO-H2O2 and EC, respectively. PC thus appears as a promising and competitive alternative for the decontamination of wastewater. In the second chapter, the detection and quantification of p-benzoquinone (BQ) was performed using the differential pulse voltammetry (DPV) technique with a diamond film sensor, in addition to BQ degradation by anodic oxidation. A series of electrochemical galvanostatic oxidation experiments with 130 mL of BQ solution was carried out in order to understand the effect of current density, pollutant concentration and initial pH using different electrolytes with similar conductivity. The ideal operating conditions were achieved in 33.3 mA cm-2, 100 mg L-1 of BQ at pH 5.0 with 50 mM Na2SO4. In addition, the evolution of short-chain carboxylic acids in this test was followed over time to suggest a possible degradation route. Demonstrating the efficiency of electrochemical technology in the degradation and evaluation of treatment.

13
  • CARLOS AUGUSTO CABRAL KRAMER
  • OXIDATION OF BANANA LIGNIN VIA THE CATALYTIC ACTION OF CO3O4 UNDER MILD CONDITIONS AND INVESTIGATION OF STABILITY,PROPERTIES OF THE βO4 BINDING AND INTRAMOLECULAR INTERACTIONS THROUGH THE DFT, QTAIM AND NCI APPROACH 

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • ANDERSON DOS REIS ALBUQUERQUE
  • ANNE GABRIELLA DIAS SANTOS
  • LUCIENE DA SILVA SANTOS
  • SAULO GREGORY CARNEIRO FONSECA
  • ÁMISON RICK LOPES DA SILVA
  • Data: Dec 13, 2021


  • Show Abstract
  • Lignin is a natural macromolecule that, in general, is formed by the aromatic units S, G and H, depending on their origin. It is noteworthy that from its structure it is possible to obtain molecules of high added value, however, the processes come up against the need to break the bond that unites these aromatic units, the βO4 bond. This work, through computational modeling methods via DFT, QTAIM and NCI, investigated the main intramolecular interactions and their properties related to this bond. The stability was also evaluated, by evaluating the boundary orbitals, of these models and their oxidized equivalents. It can be seen that lignins that have methoxyl linked to the second aromatic unit, that is, the unit that performs the βO4 bond, perform interactions that are totally different from models that do not have them. For some specific conformations, hydrogen bonds between the gamma hydroxyl and the methoxyl of SUA were characterized and these are responsible for making the βO4 bond stronger. However, the methoxylated models are dominated by repulsive and destabilizing interactions that make their βO4 bonds, in general, 4.41% weaker than the models formed by H units that perform attractive and stabilizing dihydrogen interactions. The computational modeling used confirmed that lignins derived from more oxygenated monomers have a smaller HOMO-LUMO gap and, therefore, are less stable. In the developed study, the replacement of alpha hydroxyl by carbonyl (oxidation) was able to abruptly change the electronic topology, reducing the binding energy in βO4 for all models considered. Experimentally, an efficient oxidative method was developed, which was applied in the oxidation of banana organosolv lignin via atmospheric oxygen gas with an oxidizing agent in the presence of Co3O4 as a heterogeneous catalyst at a temperature of 80°C under ambient pressure. The ideal concentration of the catalyst verified was 1% (mol/mol), which after 54 hours of reaction was sufficient for the satisfactory oxidation of the structure, which was confirmed by FTIR analysis.

14
  • KAROLINE NÓBREGA CELINO
  • Analysis of the glycerin viability as a polar phase of an emulsion based glycerin in olefin for drilling oil wells.

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • FABIO PEREIRA FAGUNDES
  • FABÍOLA DIAS DA SILVA CURBELO
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Dec 13, 2021


  • Show Abstract
  • The drilling in ultra-deep waters presents a series of difficulties and specificities, related to the depth of the well, water depth, high pressures and salt
    formations found in the pre-salt basins. Moreover, there is still a need to use fluids in compliance to environmental legislation for cleaning and disposing of
    cuttings at sea. In this sense, inverted emulsion fluids, from brine in olefin, are favorable and have been used extensively for this application. The fluids need
    to maintain their rheological properties throughout the entire drilling, also considering the variation of temperature, in order to minimize the formation of
    hydrates, interaction with clayey areas, interaction with saline zones and damage to the formation. The hypothesis of this thesis is that the substitution of
    brine for glycerin can promote the maintenance of rheological properties, as well as mitigate the interaction with clay and salt zones, not potentiate the
    formation of hydrates and give a destination to a residue from the production of biodiesel. For this purpose, in the preliminary study, the physical-chemical
    characteristics of the dispersed phase and the continuous medium were studied for application in an emulsified system of glycerin in olefin. Keeping in mind
    the initial characteristics, the emulsified system was applied as a drilling fluid, using commercial additives and comparing the rheological responses varying
    the temperature. The interaction with saline and clay zones was investigated by assessing the interaction of the dispersed phase and the continuous medium
    using clay and salt plugs. Among the main results, the glycerin obtained as a by-product of biodiesel was compatible with the commercial additives used in
    drilling fluids based on brine in olefin, demonstrating the feasibility of immediate application in drilling fluids, given the maintenance of rheological
    properties, decreasing the volume of filtrate and less reactivity towards salt and clay areas. In this way, the thesis presented a new composition of drilling
    fluid in ultra-deep waters, with the potential to minimize damage to the rock formation, through the use of a residue from the biodiesel production industry,
    without the need for previous treatments.

15
  • IZABELLE CRISTINA DA COSTA SOARES
  • Theoretical and experimental insights into degrading organic compounds: experimental conditions, technologies and pollutants.

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • ALINE MARIA SALES SOLANO
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • ELIANE BEZERRA CAVALCANTI
  • ELISAMA VIEIRA DOS SANTOS
  • Data: Dec 13, 2021


  • Show Abstract
  • Water quality, as well as its pollution, feared great concern in the scientific community. This problem has been accompanied by increasing public interest, generating a political demand to legislate more rigorously the limits of emission and content of pollutants in water. Within this context, electrochemical water treatment technologies are highly promising for environmental remediation. These technologies are based on no high oxidation power of two hydroxyl radicals (• OH), which has a high reativity to oxidize organic compost present in effluents. Therefore, at present, I study the application of different Advanced Oxidative Eletrochemical Processes (PEOAs) to treat contaminated synthetic solutions. It is endorsed by the influence of different functional groups in the core structure by potentiodynamic measurements and by computational analyzes, which will allow us to carry out morphological studies in front of orbit where the electrons are more energetic and, then, it has been carried out by transferring the electrons to the electrode surface. , which was associated with electrochemical measurements. Furthermore, the theoretical studies are used to understand electrolyte in mass, in terms of mineralization. The two corantees are reactive Orange 16, Reactive Violeta 4, Reactive Red 228 and Reactive Black 5 foram escolhidos which present the same molecular-based structure with different functional groups. No case of chapter 4 for eletrochemical and photoeletrochemical treatments using UVA and solar radiation. A solution containing or herbicide Triclopyr was treated at neutral pH by different PEOAs. In comparison with the eletro-Fenton treatments it revealed the crucial role of the photo-Fenton reaction, one time that it promoted the production of soluble Fe (II) that favors the removal of pesticides. The Fe (III) -EDDS (1: 1) complex provides an efficient ferrous catalyst for triclopyr herbicide treatment in neutral pH for the PEF process. Finally, a plausible rotation for the degradation of the herbicide catalyzed by Fe (III) -EDDS by PEF and SPEF is finally proposed based on the detected by-products: three heteroaromatic compost and four linear N-aliphatic, formamide and tarthronic and oxamic acids. The PEOAs studied in this work prove to be satisfactory and sustainable technologies for the treatment of effluents.

16
  • KARLA CAROLINE DE FREITAS ARAÚJO
  • persulfate, organic compunds, boron doped diamond, electrochemistry.

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • ELISAMA VIEIRA DOS SANTOS
  • ALINE MARIA SALES SOLANO
  • DANYELLE MEDEIROS DE ARAUJO
  • ELIANE BEZERRA CAVALCANTI
  • Data: Dec 22, 2021


  • Show Abstract
  • Oxidation of organic contaminants via sulfate radicals electrogenerated with boron-doped diamond electrode is an efficient electrochemical technique that is gaining more and more space and applications in the research field. The present work consists of the use of BDD electrodes, of different sizes and properties, for the production of persulfate during electrosynthesis. One of the stages of the research was the analysis of persulfate, before its application in organic compounds, with the objective of studying the oxidant's half-life and its potential for storage / storage, under different conditions, and with that define how many days the persulfate maintains the ability to oxidize selected organic compounds. The compounds chosen were methyl orange and pquinone, to which were added the electrogenerated persulfate solutions that were stored. The degradation of these compounds was accompanied by the use of a BDD sensor during electroanalysis.

17
  • JEFFERSON ANDREY LOPES MATIAS
  • (MATERIALS CHEMISTRY APPLIED TO BISMUTH COBALTITE-RICH NANOCOMPOSITES WITH SILLENITE CRYSTAL STRUCTURE)


  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • SIBELE BERENICE CASTELLA PERGHER
  • MARCO ANTONIO MORALES TORRES
  • JOAO BOSCO LUCENA DE OLIVEIRA
  • ADEMIR OLIVEIRA DA SILVA
  • SAULO GREGORY CARNEIRO FONSECA
  • ISAAC BARROS TAVARES DA SILVA
  • Data: Dec 28, 2021


  • Show Abstract
  • The constant scientific advancement is contributing to multifunctional materials emergence, aiming to provide the growing worldwide technology demand. Thus, the study and development of materials is directly associated with the understanding of Materials Chemistry. In this scenario, this thesis aims to apply the four pillars of Materials Chemistry (synthesis, characterization, properties, and applications) in the production of an inorganic nanocomposite rich in bismuth cobaltite with a crystalline structure of sillenite (Sillenite Co - Co3O4) as a promising candidate for scientific-technological use. Initially, in a first work, two polycrystalline samples of the nanocomposite were prepared by combustion and sol-gel methods, with grain sizes ranging from 64.4 nm to 80 nm in all phases. The combustion sample displayed a diffractogram with slightly asymmetrical sillenite peaks, which indicated the presence of sillenite with some variation in its stoichiometry. From the magnetic susceptibility, it was verified that the combustion sample has a degree of magnetic frustration twice as high as the sol-gel sample. Both samples presented a Néel temperature of 36 K for the secondary phase Co3O4 and a hysteresis at 6 K. However, in the MT measurements with a magnetic field of 200 Oe, above 148 K, only the combustion sample presented a signal superparamagnetic, this signal changes to 70 K when a 600 Oe magnetic field is applied. In a second work, directed to the application of the nanocomposite, the production process via combustion route and characterization of Sillenite Co – Co3O4 powder was reported. The dielectric characterization of the nanocomposite presented significant results in the X-band, with low values of conductivity and loss tangent from 6.0 GHz to 8.5 GHz, a characteristic that allows its application as a substrate for resonators. Therefore, the nanocomposite was applied as a substrate in a microstrip antenna. The reflection coefficient measurements displayed good agreement with the simulations, reaching only 0.39% error in the resonance frequency, validating the morphological and dielectric characterizations performed, according to the antenna design. In a third investigation, optimization of the nanocomposite synthesis was carried out based on a Box-Behnken Design of Experiments and the study of structural, chemical, and dielectric properties were performed to the samples synthetized by three different types of fuel: urea, glycine, and ethylene glycol. A total of 15 samples were prepared by combining combustion and sol-gel method steps at low temperatures to evaluate the effects of fuel type, along with the percentage of fuel and initial pH of the reaction on the relative mass concentration of the Co Sillenite phase present in the nanocomposite. Validation experiments confirmed the good predictive potential of the proposed quadratic model between the response (% CoS) and the significant variables, with the ethylene glycol sample showing the highest % CoS, with 87.92%.

2020
Dissertations
1
  • ERNANI DIAS DA SILVA FILHO
  • Superparamagnetic gels based on polyacrylamide and magnetite

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • JOSE LUIS CARDOZO FONSECA
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • SEVERINO ALVES JUNIOR
  • Data: Feb 3, 2020


  • Show Abstract
  • Polyacrylamide and magnetite gels are used for various applications due to their magnetic properties. Magnetite has some advantages such as low production cost and low toxicity. Such characteristics provide its use in biomedical and technological applications such as hyperthermia, drug release, effluent treatment, magnetic separation and abrasives. Thus, Superparamagnetic gels based on polyacrylamide and magnetite were synthesized by the in situ preparation of magnetite nanoparticles in physical polyacrylamide hydrogels (PAM) at different polymer concentrations. The formation of magnetite nanoparticles and their magnetic properties were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and Rheology. Gels show that the main functional group of PAM (amide I and amide II) appeared in the three samples of gels synthesized with magnetite. Through the structural refinement technique by the Rietveld method showed an average size of diameters ranging from 12-16.3 nm. SEM micrographs of the gel with Fe3O4 show that the materials have spherical structures. The Rheology measurements showed that the viscosity is decreasing with the shear rate and has a behavior of a non-Newtonian fluid. Magnetic measurements show that the saturation magnetization decreases with the percentage of polyacrylamide and show superparamagnetic behavior.

2
  • ELMAR DAMASCENO JUNIOR
  • Application of palygorskite in pH-responsive release of tuberculostatic drugs

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • JOSE LUIS CARDOZO FONSECA
  • SIBELE BERENICE CASTELLA PERGHER
  • NEDJA SUELY FERNANDES
  • VERA R. LEOPOLDO CONSTANTINO
  • Data: Feb 4, 2020


  • Show Abstract
  • Tuberculosis (TB) is the second leading cause of death from worsening infection worldwide. This status is mainly due to therapeutic efficacy problems encountered in existing treatments. Isoniazid (INH) and rifampicin (RIF) are very effective first-line drugs in the treatment and prevention of TB. However, administration of these drugs may cause serious side effects such as peripheral neuropathy, hepatotoxicity, hematotoxicity and other adverse effects from prolonged use of these substances, which may result in discontinuation of treatment. Thus, it is necessary to search for new delivery systems for tuberculostatic drugs, in order to avoid unwanted adverse effects, protect the drug from degradation in the gastrointestinal tract, increase its bioavailability and, consequently, improve its therapeutic efficacy. The present work studied the obtaining of pH-responsive systems for INH and RIF, using palygorskite (PAL) as nanocarrier, a natural, abundant and low cost material. The incorporation process was evaluated through a factorial design in order to investigate the influence of some factors on drug adsorption. The experiment using the maximum concentration (0.075 mg / mL for INH and 0.125 for RIF), lower PAL mass (300 mg) and lower pH (pH 2) was the most efficient compared to the other experiments performed, resulting in a higher concentration. incorporated drug dose equivalent to 12.93 mg / g PAL for INH and 33.62 mg / g PAL for RIF. The results obtained by the characterization techniques employed (FTIR, XRD, TG/DTG, DSC, Zeta Potential, SEM and EDS) and by the application of kinetic models and adsorption isotherms confirmed the incorporation of the drugs in the clay mineral and helped to elucidate the mechanism of interaction between materials. Through in vitro release studies performed for isoniazid, it was possible to prove the efficacy of the pH-dependent system obtained for the drug. More than 60% of the dose was released into the intestinal medium (pH 6.8 and pH 7.4). The kinetic study showed that the zero-order model was the best fit to the experimental data, indicating that INH is released at a long time from the palygorskite.

3
  • LAMARA MACIEL DOS SANTOS
  • ZEOLITE A WASTE-FREE SYNTHESIS: EVALUATION OF REACTIONAL PARAMETERS FOR AN ECO-FRIENDLY ROUTE

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • DULCE MARIA DE ARAUJO MELO
  • FABIO GARCIA PENHA
  • MARIELE IARA SOARES DE MELLO
  • Data: Feb 10, 2020


  • Show Abstract
  • There is a huge consumption of synthetic zeolites in the world and zeolite A has been the most used due to its versatility, being used as adsorbent, detergent additive, animal feed and agriculture. However, its route of hydrothermal synthesis does not meet the criteria of sustainability and reduction of residues. Thus, type A zeolite samples were synthesized from an experimental design, aiming to optimize the synthesis process and to evaluate the effect of crystallization time and NaOH/SiO2 and H 2 O/SiO 2 ratios. Additionally, the reuse of separated alkaline mother liquor during filtration was also studied. Significant amount of mother liquor waste is generated in the preparation of zeolitic materials. Recycling is proposed as the best solution for handling such chemical wastes. As a result, it was possible to optimize the synthesis process to obtain crystals of zeolite A, with adequate morphology and crystallinity, in 79 minutes and with a 50% reduction of water and sodium hydroxide content in the synthesis gel. Zeolite A crystals with high crystallinity could also be obtained within 60 min at 100 °C by reusing the mother liquor. The materials were characterized by powder X-ray diffraction and scanning electron microscopy.

4
  • RENATO DANTAS LUZ PEIXOTO
  • EVALUATION OF POTENTIAL OF UNSYMMETRICAL CARBONATES AS ORGANIC BASE IN NON‑AQUEOUS DRILLING FLUIDS

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • ANNE GABRIELLA DIAS SANTOS
  • LUCIENE DA SILVA SANTOS
  • MARCUS VINICIUS GOMES PAIXÃO
  • ROSANGELA DE CARVALHO BALABAN
  • TATIANA DE CAMPOS BICUDO
  • Data: Feb 19, 2020


  • Show Abstract
  • Low toxicity and considerable biodegradability are responsible by the inclusion of vegetable esters-based fluids as an altern ative environmentally correct for oil wells drilling, according to environmental agencies regulations. However, the physicochemical properties of the fatty esters result in limited applications in synthetic base fluids. The use of unsymmetrical carbonates can be considered a viable alternative, as they present several advantages over esters, such as greater thermal oxidative stability and compatibility with various elastomers. In addition, the products formed during its hydrolysis are not detrimental to rh eological properties of fluids. Additionally, they tend to have high biodegradability, since they are structurally similar to vegetable esters. Thus, the aim of this work is to synthesize unsymmetrical carbonates by the reaction between decan-1-ol and dimethyl carbonate using KOH as catalyst, and to evaluate the potential of asymmetrical carbonates as organic base in non aqueous drilling fluids. The employment of babassu esters served as a comparative for the work. The infrared spectrum provided the structural information presenting the two most important characteristics in the asymmetrical carbonates spectrum, the strong band of the carbonyl group (C═O), which appears at 1749 cm-1, and the presence of intense absorption at 1261 cm-1 of the CꟷO stretch. Due to the low pour point (−4.5 °C), fluids formulated with this organic compound probably will not freeze in the regions near the Blowout Preventer during deepwater drilling. Transport, storage and use is safe as it has a high flash point (128 °C). The relatively low kinematic viscosity (3.2 cSt) revealed this compound as promising in the formulation of non-aqueous fluids. The fluid performance, evaluated by laboratory tests (rheological parameters, electrical stability and filtrate), showed that this carbonate represents a real alternative for application in invert emulsion fluids in substitution to other organic bases. Thus, limitations on the use of ester-based drilling fluids can be suppressed by employing asymmetric carbonates as continuous phase.

5
  • ADRIANA PERPETUA FIGUEIREDO PAULISTA
  • Synthesis of the Fe-Co alloy from hybrid spheres using carboxymethylcellulose as template and its application in catalysis

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • FERNANDO JOSÉ VOLPI EUSÉBIO DE OLIVEIRA
  • JOÃO MARIA SOARES
  • RÔMULO BATISTA VIEIRA
  • TIAGO PINHEIRO BRAGA
  • Data: Feb 28, 2020


  • Show Abstract
  • Hybrid spheres is confirmed to be an efficient method in the synthesis of Fe-Co alloy. The carboxymethylcellulose-based organic precursor (CMC) was added dropwise to a solution containing Fe3+ and Co2+ , leading to the formation of the hybrid spheres from the complexation of the metal cations with the radicals present in the biopolymer (cross-linking process). The hybrid spheres were calcined in air atmosphere leading to the formation of Fe and Co based oxide. After, it was reduced with H2 flow to form the FeCo alloy. The alloy was applied in the ethylbenzene dehydrogenation reaction to styrene production (high added value product). In order to characterize the obtained materials, it was used the infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), magnetometry and gas chromatography (GC). FTIR confirms the complexation mechanism between metal ions and CMC and the complete oxidation of the biopolymer after calcination. The diffractograms confirm the formation of the FeCo alloy after reduction under H2 atmosphere. TG indicates the minimum temperature at which the alloy is oxidized, confirming the chemical resistance of the FeCo alloy against the oxidizing atmosphere. The magnetic hysteresis curves confirm the ferromagnetic nature of the FeCo alloy. The ethylbenzene dehydrogenation reaction was selective for the formation of styrene in the presence of the FeCo alloy, confirming the interesting properties of the iron-based catalysts for dehydrogenation reactions.

6
  • FRANCILENE RUFINO DE LIRA
  • Synthesis of a Solid Polymeric Electrolyte in Form Self-Sustainable Membrane - Sodium Alginate and Lithium Perchlorate.

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • MARIA GORETTE CAVALCANTE
  • ULISANDRA RIBEIRO DE LIMA
  • Data: Mar 10, 2020


  • Show Abstract
  • Self-sustainable membranes were synthesized used in a solid polymer electrolyte (SPE), having as host matrix or sodium alginate  and as site doping or perforating agent  in different volumes (1, 3, 5 and 7 mL). The membranes were obtained using the sol-gel synthesis method and then characterized by XRD, FTIR-ATR, SEM, TG/DTG and DSC. The diffractograms showed that the amorphous behavior of the pure sodium alginate membrane predominates in the membranes with salt. In the FTIR-ATR spectra no band shifting was observed, however, the physical interactions between the polymeric chains and the salt ions are confirmed by the variation of the area of two bands characterized as marker bands. As morphological images applied by SEM, which show all membranes except AlgL1, show heterogeneous surfaces with clusters of different shapes and sizes, evidencing the presence of salt in the polymeric matrix. TG/DTG curves showed the thermal behavior of the membranes showing that salt does not interfere with polymer decomposition, however, the salt decomposes at lower temperatures as its concentration in the electrolyte increases. From the TG/DTG data, a kinetic study of the thermal decomposition of the membranes was performed using the Coats - Redfern (CR) and Horowitz - Metzger (HM) methods, which suggest first order kinetics. The pre-exponential factor A and the thermal activation parameters, E*, ΔH*, ΔS* and ΔG* were obtained. Through the DSC curves it is observed that two exothermic events occur, the first related to the decomposition of the polymer while the second related to the decomposition of the salt.

7
  • MATEUS COSTA MEDEIROS
  • Obtaining High Value Added Products From The Technical Liquid Of Cashew Nuts Using Electrochemical Oxidation With Active And Inactive Anodes

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • DANYELLE MEDEIROS DE ARAUJO
  • MARCO ANTONIO QUIROZ ALFARO
  • Data: Mar 13, 2020


  • Show Abstract
  • Electro-organic synthesis is undergoing a renaissance due to the tremendous contributions of various electrocatalytic materials, as well as the use of electrical current as a cheap and suitable reagent to conduct electrosynthetic transformations, avoiding the use of oxidizing or reducing agents. Consequently, electrosynthesis has a significant impact due to its advantages such as versatility, environmental compatibility (possibility to recover and recycle unconverted substrates), automation (turning on or off electric current), inherent safety and potential cost-benefit, among others. In this context, the electrochemical synthesis mechanism depends on the nature of the electrode material used, that is, the species formed depend on the anode or cathode used. Boron-doped diamond (BDD) electrodes belong to the class of inactive anodes that lead to the combustion of organic matter, producing few intermediates and low selectivity in the reaction. However, dimensionally stable anodes (DSA) belong to the class of active anodes that are characterized in producing different intermediates and having selective reactions. Therefore, in this work, the performance of BDD and DSA (Ti/RuO2IrO2TiO2) in the electro-oxidation of cashew nut shell liquid (CNSL) was evaluated, in order to favor its conversion into products with high added value, such as carboxylic acids. The evolution of five carboxylic acids was followed over time for three different current densities, using 0.10% and 0.01% LCC in NaOH 1.00 mol L-1 for BDD and DSA respectively. At 70 mA cm-2, the most notable increase in organic acid concentrations occurred during the last two hours, reaching electrochemical conversions of 4.1 and 7.8% for acetic and oxalic acids, respectively for BDD anode, already in DSA the conversion was more selective, producing only acetic acid with a yield of 11.7% in 30 minutes of electrolysis.

8
  • THIAGO JACKSON TORRES CRUZ
  • SYNTHESIS OF ZEOLITE LTA USING LIGHT ASH FROM COAL ASH

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • FABIO GARCIA PENHA
  • MARIELE IARA SOARES DE MELLO
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: Aug 28, 2020


  • Show Abstract
  • Mineral coal is a solid fossil fuel that, in the burning process, generates large volumes of waste. As it is a waste that contains heavy metals, its disposal in inappropriate places causes great environmental impacts. In order to minimize waste management problems, use this material in the zeolite reproduction process, which are the porous crystalline materials based on aluminosilicates. The residue used as a study was supplied by SATC Criciúma - SC and presents its chemical composition 24.09% Al2O3 and 54.25% SiO2. Studies of the use of coal ash with the objective of obtaining ATL were carried out, both by hydrothermal and alkaline fusion, and the combination of two methods, varying as: crystallization time, Na / T ratio, ultrasonification, gel agitation temperature and temperature alkaline melting process of the residue. The results were characterized by X-ray diffraction techniques (XRD) and scanning electron microscopy (SEM-FEG).

9
  • WILLAME GOMES DA SILVA BATISTA
  • Evaluation of Polyester Resin as an alternative material for application in Oil Well Plug and Abandonment operations.

  • Advisor : JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • COMMITTEE MEMBERS :
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • FABRICIO GAVA MENEZES
  • PAULO HENRIQUE SILVA SANTOS MOREIRA
  • RODRIGO CESAR SANTIAGO
  • Data: Sep 10, 2020


  • Show Abstract
  • Alternative materials to portland cement have been extensively studied in recent years for application in oil well plug and abandonment operations. Among these materials, thermosetting resins have stood out due to their rheological and mechanical properties being compatible with the application in oil wells. Resin systems containing reused PET in their composition were evaluated, as well as the influence of montmorillonite and dolomite. The resin compositions were characterized using infrared, with characteristic bands of polyester and styrene monomers being identified in all systems, even with the addition of the thixotropic agent and mineral filler. Compressive strength (RC), rheology, and stability under sedimentation tests were performed. The pure polyester resin showed a RC value above 90 MPa for all curing times. This result is 12 times higher than the minimum required for abandonment operations (7 MPa). All systems presented Newtonian behavior and the addition of 5% dolomite decreased the apparent viscosity. The optimum systems was formulated with 0.1 montmorillonite and 5% dolomite. Based on the results presented, the polyester resin proved to be promising for application in operations of plug and abandonment of oil wells.

10
  • JORDAN KERVEN PATRÍCIO DA SILVA
  • 2,3-Dichloro-6,7-dinitroquinoxaline as a chemodosimeter for the detection of L-cysteine in aqueous medium

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • RENATA MENDONÇA ARAUJO
  • LIVIA NUNES CAVALCANTI
  • Tula Beck Bisol
  • Data: Oct 5, 2020


  • Show Abstract
  • Amino acids are key species in several biological processes due their role as building block for the synthesis of proteins as well as other biological functions. L-cysteine is an essential proteic amino acid, and beside other functions, acts effectively in active site of enzymes and as glutathione precursor. Due its relevance, Cys has became an interesting target for the development pf molecular systems able to detect it. This work reports the use of 2,3-dichloro-6-7dinitroquinoxaline (DCDNQX) as a functional chemodosimeter for detection of Cys in aqueous solution based on nucleophilic aromatic substitution (SNAr). DCDNQX was synthetized in good overall yield (65%) via a sequential three-step protocol. UV-Vis spectroscopy analysis indicated that DCQNQX reacts selectively with Cys over other selected amino acids (tyrosine (Tyr), alanine (Ala), lysine (Lys), Histidine (His) and glutamic acid (Glu)) in DMF-H2O 5:1 v/v solution in the presence of K2CO3. This behavior is justified by the higher nucleophilicy of tiolate over phenols and amines in SNAr reactions. Selective sensing was based on the band at 275 nm that emerges in the reaction between DCDNQX and Cys after 20 minutes. At this moment, the products from reaction of DCQNQX and Cys are under characterization in attempt to understand the whole mechanisms involved in the detection of this relevant amino acid.

     

Thesis
1
  • ÁMISON RICK LOPES DA SILVA
  • Application of density functional theory (DFT) and quantum theory of atoms and Molecules (QTAIM)in the understanding of anodic oxidation of pollutants promoted by boron-doped diamond (BDD) anode

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • ANDERSON DOS REIS ALBUQUERQUE
  • JOAO BOSCO LUCENA DE OLIVEIRA
  • DANIELA KARLA DE SOUZA XAVIER
  • SAULO GREGORY CARNEIRO FONSECA
  • Data: Jan 31, 2020


  • Show Abstract
  • In environmental electrochemistry, there is a centralized focus on effluent decontamination, using catalytic techniques and materials that promote the oxidation / mineralization of organic materials present in the effluent. Electrochemistry applied in this context is a treatment that fits green chemistry, as it avoids the use of aggressive reagents in the environment. The chemical complexity surrounding the oxidation of polluting molecules is studied step by step in order to understand and improve processes at the molecular level. One step further, as contributions from computational studies, apply to these molecular systems, have a complete character, because a literature is still considered poor in this collaboration of the fields of environmental electrochemistry and theoretical chemistry. To contribute to this focus and improve the literature, two systems have been studied. The first work, which composes these, deals with the evaluation of the result of an electroanalytical technique: cyclic voltammetry. Applied to caffeine using boron-doped diamond anode (BDD). The electroanalytical profile displayed for this system results in an oxidative peak, which presents a coffee oxidation as a direct oxidation, ie, a peak that occurs before the water discharge potential. Indicating that caffeine oxidation occurs directly on the surface of the BDD. From the information provided by the experimental measurements, a BDD surface cluster was computationally used to verify coffee-electrode interactions, obtaining thermodynamic parameters and geometric interactions by DFT, QTAIM and ELF (Electronic Location Function) calculations. According to the results of the energy analysis, obtained from the DFT, as more and less stable geometries were used thermodynamically. Topological data of interaction geometries were used using QTAIM and ELF to verify how influences occurred during an interaction and relationship to the interaction energy. The second work, which includes, deals with a more active scenario, an anodic oxidation using BDD to mineralize another pollutant, the Eriochrome Black T (EBT) in solution with Mg2+ and Ca2+ cations. The oxidation made in batch, monitoring the decontamination by COD and UV-VIS. The behavior observed was opposite to the related literature, when the treatment used was electro-fenton. In this scenario, use of DFT to obtain the complex structures formed between EBT and cations, and after qtaim calculations applied the complexes in order to analyze the Metal-binder bonding in the complexes structure. The electronic density in these bonds reveals the strength of the complexes. In order to compare the facility order in undergoing oxidation among the complexes formed, considering complex with the tri and hexavalent coordination sphere.

2
  • LISZT YELTSIN COUTINHO MADRUGA
  • CARBOXYMETHYLATION OF KAPPA-CARRAGEENAN FOR PRODUCTION OF BIOCOMPATIBLE NANOFIBERS

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • RODRIGO JOSÉ DE OLIVEIRA
  • CARLOS AUGUSTO GALVAO BARBOZA
  • ELITON SOUTO DE MEDEIROS
  • LEANDRO DE SANTIS FERREIRA
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Feb 4, 2020


  • Show Abstract
  • Chemical modifications of polysaccharides are important routes to increase, develop or change the properties of these polymers. The sulfation and carboxymethylation of polysaccharides has attracted great interest, since the modified polysaccharides present a variety of biological activities and increasing application in the production of biomaterials. However, sulfation methods generate toxic waste due to the use of strongly hydrolytic sulfating agents. In this study kappa-carrageenan (KC), a naturally sulfated polymer, was modified by carboxymethylation reaction with monochloroacetic acid in order to obtain different degrees of substitution (DS). The DS was calculated from the 1H NMR spectra and ranged from 0.8 to 1.6. The chemical structure of carboxymethyl-kappa-carrageenan (CMKC) was characterized by infrared (FT-IR) and 1H and 13C NMR spectra, which confirmed carboxymethylation. The chemical modification increased the relative viscosity of KC in water and decreased the relative viscosity in saline solution. CMKCs showed higher moisture absorption and retention as well as superior antioxidant activity when compared to KC. In the tests for antibacterial activity in solution, CMKCs with DS 0.8, 1.0 and 1.2 exhibited growth inhibition against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. Thus, in order to apply to biomaterials the synthesized polymer, nanofibers were formed through the electrospinning technique using an aqueous solution blend of polyvinyl alcohol (PVA) and 25 to 75% CMKC with DS 1.1 and posterior cross-linking by temperature. The fiber manufacturing process was completely green, with no hazardous waste produced. The nanofibers were characterized by FT-IR, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The characterization showed the presence of the carboxylate and sulfate groups in all the fibers, which proved the presence of CMKC. Cytocompatibility, cell growth and adhesion and differentiation in osteoblasts through stem cells derived from human adipose tissue (ADSC) were evaluated. The results showed that nanofibers with CMKC are cytocompatible and promote increased cell growth, adhesion and differentiation in osteoblasts. Adhesion and platelet activation assays and blood coagulation in contact with the material were performed with plasma and human blood samples. Antibacterial activity in solution and on the surface of the nanofibers were performed at 6 h and 24 h with strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Nanofibers with higher percentage of CMKC have more pronounced coagulant activity, as well as higher antibacterial activity in contact with the surface. Based on the obtained data, the biomaterial formed is a strong candidate for application in wound dressings.

3
  • LILIAN CAVALCANTE DA SILVA
  • DEVELOPMENT OF CHEMOSENSORS FOR IONS BASED ON QUINOXALINE AND QUERCETINE DERIVATIVES

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • LUCIENE DA SILVA SANTOS
  • RODRIGO CRISTIANO
  • SAVIO MOITA PINHEIRO
  • Data: Feb 10, 2020


  • Show Abstract
  • The development of artificial chemosensors for detection of ionic analytes has attracted great attention to biological and environmental fields due the possibility of fast and sensitive analysis via simple and low cost procedures. This work reports the synthesis, structural elucidation and evaluation of some quinoxaline and quercetin derivatives to detect ions in solution. Firstly, synthesis and characterization of nine novel polyfunctionalized quinoxaline potentially applied as chemosensors is presented. These compounds were obtained in good yilds (65-84%) via an one-pot procedure starting from oxidation of L-ascorbic acid followed by its reaction with two equivalents of o-phenylenediamine to afford the compound AAQX. This later reacts with aromatic aldehydes to provide a series of Schiff base as final products. Two compounds were selected to be evaluated as chemosensors. The product from reaction with benzaldehyde was verified as a selective chromogenic chemosensor for Cu2+ toward several pother cations in methanol-water 4:1 v/v. On the other hand, a nitrated compound was verified effect for detection of F- in DMSO and DMSO-water. Sensing mechanisms were proposed based in spectroscopic and theoretical data. In the second part, a multidisciplinary proposal for chemistry classes is presented. This approach is based in the ability of a coordination complex between quercetin and Al3+ to detect F- in aqueous medium. Initially, rutin is easily isolated from Bredemeyera floribunda Willd and then undergoes hydrolysis fo afford quercetin. Alternatively, rutin can be purchase at interesting price. A 2:1 coordination complex between quercetin and Al3+ (QCT2-Al3+) was characterized and applied as chromogenic and fluorogenic sensor for detection of F-. This project showed to be very interesting since it encompasses several areas, such as natural products, synthesis, organometallic chemistry and computational chemistry, leading to high stimulus for undergraduate students in chemistry courses. Lastly, a review article based on quinoxaline derivative as chromogenic and fluorogenic chemosensors for cation in solution is proposed.

4
  • LAURA GABRIELA GURGEL DE CARVALHO
  • Mango almond starch esters: synthesis, characterization and applicability study in films for food packaging and reverse emulsion systems

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ADRIANO LINCOLN ALBUQUERQUE MATTOS
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • MARCUS VINICIUS GOMES PAIXÃO
  • NÍVIA DO NASCIMENTO MARQUES
  • ROSANGELA DE CARVALHO BALABAN
  • ROSSANA MARA DA SILVA MOREIRA THIRÉ
  • Data: Jul 21, 2020


  • Show Abstract
  • After the industrial mango processing, portions of the fruit, such as peel and seed, are discarded without proper use. About 15% of the weight of mango is due to the seed, from which it is possible to obtain starch. Thus, the use of mango starch to obtain inputs that add value to industrial waste is quite promising. However, although starch is an advantageous polymer because it is biodegradable and obtained from a renewable source, it has limitations for certain industrial applications. In this context, chemical modification of the mango almond starch with vinyl laurate was carried out, with the aim of overcoming these limitations. The production of the starch ester was confirmed by infrared (IV) and nuclear magnetic resonance (NMR). The applied synthesis conditions led to the production of starch laurate with degrees of substitution 2.4 (SL1) and 0.28 (SL2). Mango almond starch showed type A crystallinity. On the other hand, its esters lost the crystallinity pattern corresponding to the granule, presenting wide and dispersive peaks, corresponding to an amorphous material. Several mixtures of starch and starch laurate were used in the preparation of polymeric films, and their mechanical and physical properties were evaluated. Starch laurate with a high degree of substitution (SL1) did not show good results in any of the methods used in the preparation of films. In turn, starch laurate with a low degree of substitution (SL2) showed promising results. The films of starch and starch laurate mixtures, with a maximum concentration of 15% for SL2 (in relation to starch), prepared by microfluidization, showed greater elongation at break, greater opacity, lower stress at break and lower Young modulus than the pure starch films. The microfluidization step was decisive for obtaining films with low water vapor permeability values. In a second aspect of applicability, SL1 (starch laurate with degree of substitution 2.4), which did not present good properties in films for food packaging, had its performance evaluated as a rheological modifier in an emulsion of brine in olefin, aiming application in drilling fluids. Unlike starch and SL2, SL1 showed good solubility in olefin and provided a significant increase in viscosity in the reverse emulsion used as a model.

5
  • MONICKARLA TEIXEIRA PEGADO DA SILVA
  • Synthesis of nanocomposites based on Fe2SiO4-Fe7Co3 dispersed in SBA-15: Application as adsorbent and magnetically separable photocatalyst  

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • JOSÉ MARCOS SASAKI
  • LUCIENE DA SILVA SANTOS
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • VINÍCIUS PATRÍCIO DA SILVA CALDEIRA
  • Data: Jul 22, 2020


  • Show Abstract
  • The present study describes the synthesis of a new type of Fe2SiO4-Fe7Co3 based nanocomposite dispersed in the mesoporous material SBA-15 in order to apply in the dyes adsorption, in the photocatalytic degradation of methylene blue (MB) and consequent magnetic separation. The parameters studied were: the reduction temperature and amount of hydrogen used in the synthesis and how these affect the physicochemical properties of the oxide-alloy mixture with iron and cobalt, as well as the adsorption capacity and photodegradation of methylene blue. The prepared materials were characterized by X-ray diffraction (XRD), Mössbauer spectroscopy (MS), X-ray photoelectron spectroscopy (XPS), vibratory sample magnetometry (VSM), temperature programmed reduction (H2-TPR), N2 or Aradsorption and desorption isotherms , Scanning electron microscopy (SEM-FEG) and Transmission electron microscopy (TEM). The XRD results together with the TPR profiles confirmed the formation of Fe2SiO4-Fe7Co3-based nanocomposites at temperatures between 690 and 720 °C and amount of H2 between 0.5 and 2%. The increase of the reduction temperature and the increase of H2 content in the reduction mixture led to the formation of a higher amount of alloy compared to oxide according to the data obtained by the Rietveld refinement. Low-angle XRD, N2 isotherms, and TEM images show the formation of the SBA-15-based mesoporous support with a high specific area of 640 m/g². However, the surface area and mesoporous structure of the silica was slightly altered (to 420 m/g²) after Fe and Co insertion due to partial pore filling by the composite. For samples containing the metals dispersed on SBA-15, there may be an interconnection between mesopores according to scanning hysteresis loop from N2 and Ar isotherms accompanied by mathematical models. Adsorption tests confirmed that the material reduced at 700 °C using 2% of H2 had the highest adsorption capacity for methylene blue (MB) dye. The nanocomposites obtained have good adsorption capacity for MB dye and can be easily separated from the final dispersion by applying an external magnetic field after adsorption. The photocatalysis results confirmed that the silica support is essential to optimize the photocatalytic activity of the Fe and Co species in the dye degradation, favoring the accessibility of active sites.  The attraction of the dye by the nanocomposite occurs mainly by π-π interactions and the mixing of Fe2SiO4 and Fe7Co3 phases leads to a synergistic effect which favor the methylene blue adsorption and the photocatalytic activity process compared to the same isolated phases. The degradation of the MB occur through a sequence of reactions both on the solid surface and on the solution.

6
  • MARIANA ALVES LEITE DUTRA
  • POLYACRYLAMIDE AND STARCH HYBRIDS HYDROGELS: SYNTHESIS, CHARACTERIZATION AND STUDY OF APPLICABILITY IN WASTEWATER

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • ADRIANO LINCOLN ALBUQUERQUE MATTOS
  • JOSE LUIS CARDOZO FONSECA
  • MARCUS VINICIUS GOMES PAIXÃO
  • MORSYLEIDE DE FREITAS ROSA
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Aug 14, 2020


  • Show Abstract
  • Starch obtained from Tommy Atkins mango kernel was used in the manufacture of acrylamide hydrogels. These hybrid hydrogels were synthesized by radical in aqueous medium and characterized by FT-IR, 13C NMR, SEM, XRD, rheometry and degree of swelling. The different molar proportions of starch / acrylamide and MBA used in the feed caused changes in viscoelastic properties, gelling kinetics, swelling degree and surface morphology. The synthesized hydrogels were evaluated for the potential of adsorption of phenolic pollutants from contaminated waters, proving to be efficient in removing these residues. The equilibrium adsorption (Qeq) values ranged from 2 to 21 mg / g and were strongly dependent on acrylamide, starch and MBA concentrations in the system. The type of adsorption isotherm that best fitted was that of the Freundlich model, with R2 values between 0.95 - 0.97. Hydrogels also showed efficiency in the release of these phenolic pollutants, indicating the possibility of reuse of these materials. In addition, in a second strand of applicability in contaminated waters, hydrogels were able to incorporate silver nanoparticles in their three-dimensional networks, in order to obtain nanocomposites with potential to detect possible water contaminants in the order of 10-8 mol. L-1 using the surface amplified Raman spectroscopy (SERS) technique.

7
  • RAFAEL VIANA SALES
  • EXPERIMENTAL AND THEORETICAL STUDY OF REAL DIESEL ADSORTIVE DESULFURIZATION USING HIGH EFFICIENCY MESOPOROUS MATERIALS

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • ANNE GABRIELLA DIAS SANTOS
  • ENRIQUE RODRÍGUEZ CASTELLÓN
  • LUCIENE DA SILVA SANTOS
  • MIGUEL ANGELO FONSECA DE SOUZA
  • TIAGO PINHEIRO BRAGA
  • VINÍCIUS PATRÍCIO DA SILVA CALDEIRA
  • Data: Aug 28, 2020


  • Show Abstract
  • The burning of fossil fuels emits sulfur oxides (SOx), which negatively affect human health and the environment, in addition to being highly undesirable by oil refineries. Researchers have sought to develop alternative methods to conventional technology, hydrodesulfurization (HDS), which is an expensive and ineffective method for removing heavy sulfur molecules. Thus, in this work, the mesoporous silicas MCM-41 and SBA-15 were synthesized and modified with metallic cations Ni2+ and Ag+ for application in adsorptive desulfurization of real diesel fuel. MCM-41 was obtained from green silica (amorphous silica MPI), from beach sand, and commercial silica. The pure and modified adsorbents were characterized by X-ray diffractometry (XRD), N2 adsorption-desorption isotherms, high-resolution scanning electron microscopy by field emission (SEM-FEG), scanning transmission electron microscopy  (STEM), high-resolution transmission electron microscopy (HRTEM) and X-ray excited photoelectron spectroscopy (XPS). These techniques were important for the elucidation of materials of the type MCM-41 and SBA-15. The results of the SEM-FEG and STEM micrographs coupled with X-ray spectroscopy by dispersive energy (EDX) showed a uniform dispersion of Ag nanoparticles on the supports. Molecular dynamics simulation, using the DFT/ONIOM method, and XPS data revealed that the adsorption of aromatic sulfur compounds by AgMCM-41 is controlled by the interactions between the sulfur atoms and the silver species. The best fit of the experimental data to the kinetic model of pseudo-second order and to the Langmuir equilibrium model is an indication that chemisorption mechanisms, especially π type complexation, govern the removal of sulfur compounds by the AgMCM-41 and AgSBA-15 adsorbents, under the conditions studied, which is in agreement with the theoretical study and the XPS results. The maximum adsorptive capacities for AgMCM-41 obtained from sustainable silica and for AgSBA-15 were 31.25 mg‧g-1 and 20.30 mg‧g-1, respectively. The pure and silver modified supports showed a satisfactory regeneration rate, after 5 recycling steps, using a chloroform/hexane/acetone solution.

8
  • ADRIANO MARTINEZ BASSO
  • Oligomerization of ethylene using Ni/β-diimine complexes heterogenized in mesoporous materials: Effect of morphology and structure.

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • CRISTIANO FAVERO
  • ELEDIR VITOR SOBRINHO
  • FABIO GARCIA PENHA
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • Data: Sep 25, 2020


  • Show Abstract
  • Mesoporous compounds of type SBA-15 with fiber, platelet, rod and enlarged platelet morphology and mesoporous type KIT-6 were covalently anchored to the β-diimine 2-phenylamine-4-phenylimine-2-pentene (L2) ligand. The enlarged platelet morphology SBA-15 was also anchored to the β-diimine 2-orthodisopropylphenylamine-4-orthodisopropylphenylimine-2-pentene ligand (L1). The hybrid materials formed were complexed with nickel. The catalytic precursors Ni-β-diimine-mesoporous were tested for heterogenized ethylene oligomerization. The materials were characterized by low angle XRD, thermogravimetric analysis, N2 sortometry, NMR-1H, NMR-29Si, elemental analysis, atomic absorption spectroscopy, scanning and transmission electron microscopy. The results showed that all complexes were more selective and less active. Among the SBA-15, the one with platelet morphology had the highest activity (12,103 h-1) maintaining the selectivity for a-C4 above 90% for at least three catalytic cycles. Comparing the SBA-15 with the KIT-6, this one had better activity (6.0.103 against 3.0.103 h-1). The selectivities for a-C4 were practically equal (96% for SBA-15 and 94% for KIT-6), keeping these rates above 90% for at least three catalytic cycles. The L1 ligand had low activity (0.3.103 h-1 against 3.0.103 h-1 of the L2 ligand) and favored the formation of 59% polymers.

2019
Dissertations
1
  • ERIVALDO PAULINO DA COSTA
  • Multicomponent synthesis of substituted 3-styryl-1H-quinoxaline-2-ones in aqueous medium

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • ROSANGELA DE CARVALHO BALABAN
  • RODRIGO CRISTIANO
  • Data: Jan 21, 2019


  • Show Abstract
  • Nitrogen heterocycles compounds are of great relevance due their applications in many scientific areas, notably in the development of new materials of technological interest, as well as therapeutic agents and other biological active compounds. Recently, application of green chemistry concepts highlighted the relevance of multicomponent reactions (MCR) in aqueous medium to organic synthesis. This work reports the synthesis of 3-styryl-1H-quinoxaline-2-one-based nitrogen heterocycles (SQXO) based in MCR protocol in aqueous medium. The tri-component systems, which involves reaction of o-phenylenediamine sodium pyruvate and different aldehydes, were carried out in 20% aqueous acetic acid, and in the presence of sodium acetate. Fourteen SQXO derivatives, including eight new compounds, were obtained in 65-92% in 8-14 hours. Products were properly characterized by melting point as well as infrared and nuclear magnetic resonance (1H and 13C) spectroscopies. Reactions are supposed to proceed via mechanism involving initial condensation of aromatic diamine and sodium pyruvate, to afford 3-methyl-1-quinoxaline-2-one, which reacts with different aldehydes via aldol-type condensation. It is important to point out that only water molecules are released to the medium during all stages. This green synthetic protocol becomes especially attractive due the applications of SQXO derivatives in many areas, notably those associated to biological and material fields.

2
  • LUIZ HENRIQUE MEDEIROS DA COSTA
  • REGIOSELECTIVITY OF THE N-/O-NITROSO-ALDOL REACTIONS: a DFT study of the reactions of nitrobenzene with morpholine and pyrrolidine

  • Advisor : MIGUEL ANGELO FONSECA DE SOUZA
  • COMMITTEE MEMBERS :
  • MIGUEL ANGELO FONSECA DE SOUZA
  • DAVI SERRADELLA VIEIRA
  • GUTTO RAFFYSON SILVA DE FREITAS
  • Data: Feb 25, 2019


  • Show Abstract
  • Aromatic C-nitroso compounds have been widely studied because of their versatility. Investigations of these compounds can be found in several areas of scientific knowledge. The nitroso group (R-NO) acts ambivalently, that is, as nucleophile and electrophile, reacting with biomolecules that have sulfur atoms (nucleophile), for example. Aldo N-/O-Nitroso reactions have been explored, in particular, using nitrosobenzene (PhNO) for new synthetic routes. The investigation of the reactive processes in computational chemistry steps, essentially, by calculations of electronic energy, in which information is obtained on the energies and the relative structural changes of the species involved in the chemical reactions. In this work, computational methods were used to understand how mechanical processes occur: 1-morpholine-1-cyclohexene reacting with nitrosobenzene and 1-pyrrolidine-1-cyclohexene also reacting with nitrosobenzene. All optimized geometries of reaction were calculated using the DFT method, functional / base set M06-2X / 6-31+G(d,p). After this step, the single point was made of these optimized geometries, but we used the B2PLYPD3 functional and the base set 6-311G(2d,p), to obtain more accurate results. The results showed that the reaction process goes through three stages: transition states 1 (TS1), zwitterionic intermediates and transition states 2 (TS2). Analogously to the reactions of Diels-Alder, the reactions studied present endo and exo isomerism. It led to eight possible confomation for the TS1 of each reaction, as well as for the intermediates. In TS2, however, only 4 structure was obtained for reaction with 1-morpholinecyclohexene, whereas structures with exo isomeria would change to endo isomerism. However, with pyrrolidine, two conformations were obtained. Furthermore, for the reaction of 1-morpholinecyclohexene, a reaction mechanism was presented which corroborates with experimental studies. With 1-pyrrolidinecyclohexene, the method used was not effective to be in agreement with experimental results. Thus, this work provides a perspective for elucidation of the aldol N- / O-Nitroso reaction.

3
  • JÉSSICA NAYARA DA SILVA CÂMARA
  • SYNTHESIS OF COMPOSITES FROM POLYVINYL ALCOHOL INCREASED WITH NON-METAL RESIDUES OF PRINTED CIRCUIT BOARDS

  • Advisor : ADEMIR OLIVEIRA DA SILVA
  • COMMITTEE MEMBERS :
  • ADEMIR OLIVEIRA DA SILVA
  • PAULO ROBERTO CUNHA DOS SANTOS
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: May 13, 2019


  • Show Abstract
  • The renewal of technologies causes the increase of electronic waste in the environment. The search for methods for the treatment of these wastes generates great discussions at national as well as international level. The printed circuit boards coming from obsolete equipment arouse great interest in researches, since they have several metals in their composition, that can be recovered. However, there are still few studies that seek to reuse the substrate from the removal of metals. Composite materials have been widely studied because they provide improvements in the mechanical, thermal and physicochemical properties of materials for certain applications. In this work were developed composites with residues of printed circuit board, having as its matrix the polyvinyl alcohol. 5%, 10%, and 20% by weight of plate powder were used for the production of the composites, which were submitted to thermal analysis (TG/DSC). The mechanical properties (wear and friction coefficient) were determined by mechanical pin-disk test. Surface topography was analyzed by Scanning Electron Microscopy (SEM). The samples were then subjected to the flammability test to evaluate the flame behavior and characterized by X-ray fluorescence and absorption spectroscopy in the infrared region with Fourier transform. Based on the results of the mechanical test, it was verified that there was no significant variation in the coefficient of friction and in the wear of the materials. In relation to the thermal analysis, it was verified the reduction of the thermal stability and the production of large number of residues with the increase of the load percentage. This growth is due to the presence of silicon compounds and metals present in the powder of the plates that qualify the composites as flame retardants. In the flammability test, it was possible to observe that the increase of the mass of the plate of dust causes the increase of the resistance of the flame propagation in the composites, causing very little damage to the materials.

4
  • THUANNY MOURA DE SOUSA
  • DEVELOPMENT AND REACTIVITY OF RUTHENIUM NITROSYL COMPLEXES WITH POSSIBLE ANTIBACTERIAL ACTION

  • Advisor : FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • COMMITTEE MEMBERS :
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANIEL DE LIMA PONTES
  • TERCIO DE FREITAS PAULO
  • Data: Jul 2, 2019


  • Show Abstract
  • The present work aims at the development of nitrosyl ruthenium complexes capable of acting as a donor of nitric oxide in biological systems, considering that this molecule acts in a variety of physiological processes such as neurotransmission, blood pressure regulation and participation in the immune system in the fight against tumor cells and intracellular parasites. For this reason, we present the synthesis, characterization, reactivity and antibacterial assays of cis-[Ru(bpy)(phen)(L)(NO)] (PF6) 3 type complexes where L are the thiourea and 4- nitroimidazole, bpy = 2,2'-bipyridine and phen = 1,10'-phenanthroline. The compounds were obtained from the cis- [Ru(bpy)(phen)Cl2] precursor complex in water and ethanol with addition of the ligands under study. Through the UV-Vis technique, in aqueous solution, it was possible to identify the MCLT bands for the polypyridine linkers as for the nitrosyl linker in the 420-480 nm range. With respect to the infrared spectra, the complexes exhibited bands in 1926 and 1942 cm-1 attributed to ѵ(NO+) with thiourea and 4-nitroimidazole, respectively, indicating the coordination of the nitrosyl ligand. The cyclic voltammograms obtained in NaTFA 0.1 mol / L and pH 3.5 showed E1/2  in 32 mV for the complex with thiourea and 112 mV for 4-nitroimidazole, both referring to the NO+/0 redox pair. Regarding the reactivity, the complexes showed to be able to release the nitric oxide by photochemical reduction and that the nitrosyl nitrite interconversion reaction occurs at pH 6.70 and pH 5.86 for the compounds with thiourea and 4-nitroimidazole, respectively. The antibacterial activity of the nitrosyl complexes was investigated against the bacteria Pseudomonas aeruginosa (ATCC-9027) and the cis-[Ru(bpy)(phen)(TU)(NO)](PF6)3 complex against Staphylococcus aureus bacteria (ATCC- 25923/ATCC-700698) and Staphylococcus epidermidis (ATCC-12228 /ATCC-35984). The test revealed a MIC of 121.5 μM, from the thiourea complex for Pseudomonas aeruginosa (ATCC-9027) and a MIC of 511 μM for the bacteria Staphylococcus aureus (ATCC-25923/ATCC-700698) and epidermidis (ATCC -12228). This indicates that the compound under study has the ability to inhibit the growth of these bacteria. In addition, the compound showed a MBC of 511 μM for Staphylococcus aureus (ATCC-25923) and Staphylococcus epidermidis (ATCC-35984) suggesting it to be an antibacterial agent.

5
  • HELOISE OLIVEIRA MEDEIROS DE ARAUJO MOURA
  • INVESTIGATING THE EFFECT OF PRETREATMENTS ON THE STRUCTURE OF LIGNOCELLULOSIC BIOMASSES FOR THE ISOLATION OF HIGH-REACTIVITY CELLULOSES

     
  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • LEILA MARIA AGUILERA CAMPOS
  • LUCIENE DA SILVA SANTOS
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Jul 12, 2019


  • Show Abstract
  • The lignocellulosic biomass is composed of cellulose, hemicellulose and lignin strongly bonded to each other and stands out as a highly available and promising raw material for conversion processes. Cellulose has been widely studied in literature as a renewable source for the production of chemical platforms, molecules of great importance for the biorefinery industry capable of being converted into the most diverse chemical compounds used in today's society. However, the efficient separation of cellulose is still challenging due to the recalcitrant nature of the biomass. Thus, this work aims to evaluate the efficiency of the combined acid/peroxide-alkaline (APA) pretreatment, the ultrasound cavitation (US) and the association of both methods (USA + PA) under different conditions in increasing the accessibility of common residual biomasses in the Brazilian Northeast: sugarcane bagasse (Saccharum officinarum), corn cob (Zea mays) and prickly pear pseudostem (Opuntia ficus-indica L. Mill.), as well as on the crystallinity changes of the celluloses that will be isolated later. For this, the peak deconvolution of X-ray diffraction (XRD) data was compared to the absorption bands generated by the Fourier transform infrared spectroscopy (FTIR) analysis of the samples, in order to evaluate the effectiveness of the APA treatment under conditions already found in the literature and in a new methodology with ultrasonic assisted acidic step (US). The evaluation of the polymorphism and inferred crystallinity parameters showed that cavitation made possible the production of a more accessible biomass under milder conditions of acid treatment (30 min, 90 °C) for removing hemicellulose and with shorter time (60 min) of the delignification step (peroxide-alkaline) for sugarcane bagasse and prickly pear pseudostem samples. The deconvolution methodology was also applied to the derived thermogravimetric curves (DTG) and was successful for separating the overlapping mass loss events and in the determination of the mass content of lignocellulosic fractions by calculating the area under each degradation curve, with precision and accuracy comparable to the standard characterization method for these biomasses.

     
6
  • LAYSA RENATA DUARTE BRITO SABINO
  • REMOVAL OF EMERGING POLLUTANTS (RIFAMPICIN AND BRILLIANT BLUE) FROM THE AQUEOUS ENVIRONMENT USING ELECTROCHEMICAL TECHNOLOGIES: STUDY OF THE EFFECTS OF MAIN PARAMETERS IN THE DECONTAMINATION OF WASTEWATER

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • ELISAMA VIEIRA DOS SANTOS
  • MARCO ANTONIO QUIROZ ALFARO
  • Data: Jul 15, 2019


  • Show Abstract
  • The most easily detected emerging pollutants in the aquatic environment are antibiotics and dyes, the first to have a refractory feature making it difficult to effectively remove wastewater from sewage and treatment plants, the second to be produced and used on a large scale in several industrial stages. On this context, there is a need for the application of advanced techniques for the degradation/removal of these pollutants that are in environment and will, in the long term, cause resistance to drugs and cancer in humans. In this study was done the treatment by anodic oxidation and electro- fenton of synthetic effluents contaminated with a drug used to Tuberculosis, Rifampicin and the other contaminated with the Brilliant Blue FCF using Boron Doped Diamond (BDD) electrodes and Carbon Felt (CF). The effect of the application of different currents on the degradation and the influence of the initial concentration of the pollutant were examined. Comparative studies using other commercial electrode materials were also investigated, as was the evaluation of the efficiency of different electrolytes. The degradation of rifampicin had better results with the BDD / CF material at current density of 50 mAcm-2, achieving 98% COD removal. While the removal of Brilliant Blue had good results from the application of the current of 250 mA for 6 hours, depending on the initial concentration, reaching current efficiency of 93%.

7
  • EDUARDO AUGUSTO DA SILVA DINIZ
  • STUDY OF THE DYNAMICS AND STRUCTURAL CHARACTERIZATION OF THE PROTEIN INTERFACE IN XILANASE-XBP CHIMERAS BY MOLECULAR SIMULATION

  • Advisor : DAVI SERRADELLA VIEIRA
  • COMMITTEE MEMBERS :
  • DAVI SERRADELLA VIEIRA
  • ANDERSON DOS REIS ALBUQUERQUE
  • NORBERTO DE KASSIO VIEIRA MONTEIRO
  • Data: Jul 17, 2019


  • Show Abstract
  • In the field of molecular biology and biotechnology, proteins owning two or more combined activities, coupled with an appropriate structural stability, have been widely applied. A few years ago three hybrid enzymes / chimeras were produced by a semi-rational protein fusion strategy, resulting in the insertion of a Xylose Binding Protein (XBP) to a Xylanase GH11, whose function is to degrade xylan , the main component of the plant cell wall. The enzymes produced showed a catalytic efficiency in the degradation of xylan two to three times higher than the isolated xylanase, besides increasing its activity in the presence of xylose, a substance that would naturally inhibit xylanase alone. Xylose activation occurs via allosteric mechanism. Currently, simulation techniques such as molecular dynamics (DM) are the best ones to bring forward detailed information at the atomic level regarding structural protein behavior, but they present limited timescale to investigate the problem fully, because the structures generated can be trapped in a local energy minimum. In this work, we explore alternative ways of circumventing these limitations, with a computationally less demanding technique for generation of new ensemble of structures, the CONCOORD, for the case of chimeric proteins with allostery. More robust statistical techniques (PCA and FMA) were used to analyze the results in order to provide a more complete analysis of the functional motions in these proteins. In addition, a detailed structural characterization of the protein interfaces between the enzymatic domains was performed since these interfaces play a fundamental role in the allosteric effect. The FMA analysis indicated that the stability of the interface is well related to a specific movement, the rotation of the xylanase and XBP domains in opposite directions, which showed good correlation with the interfacial energy for chimeras 209, 262 and 271. In the case of chimera 271 the correlation was slightly worse due to a more intense and extensive movement of the thumb region (xylanase) compared to chimeras 209 and 262. The presence of intermittent interfacial residues, especially in chimeras 209 and 262, was identified. Chimera 271 has the most stable interface, with the least amount of intermittent interfacial residues. It was observed that the occurrence of a high structural variability during the simulations is associated to a change in the interfacial energy, mainly for chimeras 209 and 262, that is, when the protein undergoes some considerable conformational transition, the interfacial energy responds, increasing or decreasing, which is in agreement with the existence of intermittent interfacial residues. Detection of such residues is fundamental to understand the structural allosterism and stabilization mechanism determined by the XBP insertion position in xylanase. A strategy which will be adopted in future studies, in continuity to the work presented here, in order to improve the stability of the protein interface and, consequently, the allosteric effect, will be the insertion of disulfide bridges at the interface concentrating on the intermittent and inert residues. The mutant hybrid enzymes produced in silico can be tested experimentally by collaborating groups

8
  • MARCEL GALDINO DE SOUZA
  • Ni-BASED CATALYSTS SUPPORTED IN MgAl2O4: Comparative study of One-pot and impregnation methods

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • RENATA MARTINS BRAGA
  • RODRIGO CESAR SANTIAGO
  • Data: Jul 19, 2019


  • Show Abstract
  • This work evaluates the fuel concentration and the method of synthesis of catalysts for dry reforming methane. The catalysts were synthesized via microwaves, using urea as fuel with a concentration between 25 and 100% of stoichiometric; also, the impregnation method was used to incorporate the nickel for two of these catalysts, that were appointed Ni-MgAl (IBT); Ni-MgAl (IAT) where IAT make reference for high content of urea and IBT for lower urea content. The others two catalysts Ni-MgAl(OBT) e Ni-MgAl(OAT) was synthesized by One Pot, keeping the same urea concentration such as used in the catalysts impregnated. The catalysts was characterized by X Ray Diffraction (XRD), Specific Area (BET), Scanning Electron Microscope (SEM), Temperature-Programmed Reduction (TPR). According to XDR, the material with high urea content presented crystal structures and well defined phases (NiO, MgO, NiAl2O4 and MgAl2O4 ), demonstrating that the fuel concentration interferes in crystallinity, already the BET showed that this material has low superficial area, which is normal for this type of oxide. The catalysts prepared with low urea content demonstrated through XRD amorphous feature, however, the refinement by the Rietveld method, indicated the presence of the same phases that others two catalysts with high urea content. This occurs most likely due to incomplete combustion, once time that urea content was low. The result of catalysts tests showed considerable percentages of conversion of methane into synthesis gas ate 750°C

9
  • MAYRA SILVA COUTINHO
  • DEVELOPMENT OF CHROMOGENIC SENSORS BASED IN ENZYMATIC REACTIONS AND SILVER NANOPARTICLES FOR ANALYSIS OF ASCORBIC ACID AND IRON (III) IN AQUEOUS MEDIUM

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • ELISANE LONGHINOTTI
  • FABRICIO GAVA MENEZES
  • JOSE LUIS CARDOZO FONSECA
  • TIAGO PINHEIRO BRAGA
  • Data: Jul 22, 2019


  • Show Abstract
  • The development of chemical systems aiming detection of specific analytes in solution has attracted great attention due the possibility of fast, low cost and practical implementation. In this context, methods based on enzymatic reactions and nanostructured systems play a relevant role. This work consist in two main parts. Firstly, a new method for detection of ascorbic acid (AA, vitamin C) based on its interfering effect in the quantification of glucose by the enzymatic colorimetric method is presented. This method is based in the inhibition of chromophore quinoneimine, generated by sequential enzymatic processes, which its concentration is proportional to concentration of glucose in the medium.  UV-vis analysis showed a linear correlation between decreasing of quinoneimine concentration concomitantly to increasing of AA concentration. The method was validated by quantification of AA from commercial effervescent tablets, with satisfactory errors, from 0.01 to 1.25 %, and limits of detection and quantification of 0.045 and 0.138 mg.L-1, respectively. In the second part of the work, silver nanoparticles functionalized with the natural product rutin (RU-AgNPs)  were employed in the detection of Fe3+ ions in solution, in the presence of AA. In the best experimental condition (AgNO3, 0,2mM; AA, 0,1 mM; NaOH, 0,1 M e AA, 1mM), according to UV-vis analysis, small but polydisperse nanoparticles (4.1 nm), as verified by transmission electronic microscopy. In the presence of Fe3+, these nanoparticles increase in size (14.7 nm average) and undergo aggregation, as verified by TEM. These effects are not verified in the presence of Cu2+, Zn2+, Hg2+, Ni2+, Pb2+, Mg2+, Cr3+, Sr2+, Ba2+, Cu+ e Al3+. Although Co2+ ions also affects the RU-AgNPs, this effect is not pronounced enough for interfering in the detection of Fe3+ ions. Mechanistically, adsorption of anionic RU to silver surface via 3-hydroxychromen-4-one moiety, since it is the main site to coordinate to metal, while addition of Fe3+ induces to the formation of a coordination complex through anionic catechol group, in which at least 2:1 ligand-Fe3+ stoichiometry is required for aggregative effect. In this process, AA has a crucial role for selective detection and two possible explanation include avoid of previous oxidation of RU by silver and/or coordination of ascorbate do other cations. UV-vis analysis showed a linear correlation between concentration of Fe3+ ions in solution (1-10 μM) and the decreasing in the surface plasmon resonance band (396 nm) associated to RU-AgNPs. Limits of detection and quantification for quantification of Fe3+ were found to be 17 nmol L-1 e 56 nmol L-1, respectively.

10
  • SUEDSON DE CARVALHO SILVA RODRIGUES
  • STRUCTURAL AND BIOLOGICAL STUDIES OF STIGA15 PEPTIDE AND THE RELATIONSHIP WITH THE NATURAL PROTOTYPE STIGMURIN

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • RENATA MENDONÇA ARAUJO
  • FABRICIO GAVA MENEZES
  • MATHEUS DE FREITAS FERNANDES PEDROSA
  • EDILBERTO ROCHA SILVEIRA
  • Data: Jul 22, 2019


  • Show Abstract
  • Due to the broad spectrum of biological activities reported in the literature for peptides present in the venom of scorpions, an increase has been observed in the studies of these molecules, especially the antimicrobial peptides, which are investigated as strategic alternatives to face problems such as resistance to conventional antibiotics. It is known that the mechanism of action of antimicrobial peptides occurs in large part by the interaction with the microorganism membrane, causing destabilization of the lipid bilayer, resulting in the formation of pores, which leads to cell lysis. However, the details of these interactions are not yet fully known and can vary significantly from peptide to peptide, therefore, membrane-peptide interaction studies with biomimetic media are necessary. The present work proposes the synthesis and the characterization of the bioactive peptide StigA15, designed from the primary sequence of Stigmurin, which has originally been isolated from the Tityus stigmurus scorpion. The peptide was obtained from Fmoc solid phase peptide synthesis and Isothermal Titration Calorimetry (ITC) and Circular Dichroism (CD) and Nuclear Magnetic Resonance (NMR) spectroscopies were used as main research tools and the respective experiments were performed in media that mimic membrane environments. When compared the activity of StigA15 to that of the of the wild-type Stigmurin, it was observed that the substitution of two serine residues by two charged lysines resulted in higher activities against Gram-positive and negative bacteria as well as against fungi. According to preliminary studies, it has been identified that StigA15 has a higher hydrophobic moment and therefore could be inserted more deeply in the membrane than Stigmurin. StigA15 presents selectivity towards pattogen cells, since it presents very low hemolysis rates at the active antimicrobial concentrations. This selectivity is further supported by ITC experiments that indicated significatly stronger interactions of StigA15 with anionic vesicles, when compared to zwitterionic vesicles. CD and NMR spectroscopies indicated that the peptide adopts helical conformations in membrane mimetic enviorenments. In addition, NMR spectrosccopy proved that the peptide shows high amphipathicity which is, together with its net positive charge (+4), a feature commonly found in several antimicrobial peptide sequences. Therefore, here is presented a novel peptide sequece with high biotechnological potential

11
  • NATHÁLIA OLIVEIRA FELICIANO
  • ADDITION OF POLYMER IN MICROEMULSION: CHARACTERIZATION EFFECT IN THE EOR TEST

  • Advisor : ALCIDES DE OLIVEIRA WANDERLEY NETO
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • JOSE LUIS CARDOZO FONSECA
  • MONICA RODRIGUES DE OLIVEIRA
  • Data: Jul 29, 2019


  • Show Abstract
  • After exhaustion of its natural energy, the reservoirs retain high amounts of hydrocarbons. The application of advanced oil recovery methods is a way of increasing the oil recovery factor resulting from the use of conventional recovery methods, which are capable of shifting only about 30% of the oil and this is due to the high viscosity of the oil and the elevated interfacial tensions between the injection fluid and the fluid to be displaced. Among the advanced recovery methods, there are thermal, miscible and chemical methods. The application of the chemical methods is done when a certain chemical interaction between the injection fluids and the fluid to be displaced is desired. This work aims to study microemulsion systems (with and without polymer in its composition) for the advanced recovery of oil, determining the phenomena of interface and viscosity, and evaluating their recovery efficiencies. For this, these systems were characterized by measurements of aggregate size, viscosity, surface tension, contact angle and oil recovery. The microemulsion systems were obtained by choosing points in the Pseudoternary diagram, of the following composition: Ultranex Np 120 (Surfactant - T), secondary butanol (Co-surfactant - C), heptane (oil phase - FO), distilled water (aqueous phase - FA) and polyacrylic acid (polymer), in a fixed ratio of C/T = 1. The chosen systems have a fixed quantity of 5% m/m FO, while the quantities of C/T and FA vary between 35 and 60%. The systems with polymer in its formulation were obtained with the addition of 0.2% m/m of the polymer. A comparison made between the surface tension results and the viscosity measurements showed that the oil displacement, for the systems without polymer, is mainly due to interfacial action, while for the systems with polymer, the recovery obtained is mainly due to mechanical displacement. In addition, all the systems under study presented positive results for tertiary recovery, increasing the wettability of sandstone, reaching 41% of original oil in place recovery (% OOIP).

12
  • LUIS OTAVIO DE ARAUJO
  • ACTIVE PACKAGING: SYNTHESIS OF ANTIMICROBIAL FILMS BASED ON LOW DENSITY POLYETHYLENE AND A ZEOLITE CONTAINING SILVER

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • FABIO GARCIA PENHA
  • KATYA ANAYA JACINTO SCATTONE
  • MARIELE IARA SOARES DE MELLO
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Oct 29, 2019


  • Show Abstract
  • Active antimicrobial packagings are materials endowed with the ability to inhibit and eliminate microorganisms that deteriorate food. Considering the great importance of practices aimed at obtaining safer food, less waste and longer shelf life of these products, the present work had the objective of synthesizing low density Polyethylene and zeolite A composite films substituted with different contents of silver for use as active packaging. 1%, 5% and 10% silver were inserted by means of cation exchange in the structure of zeolite A. The starting materials were characterized by X-ray powder diffractometer, scanning electron microscopy, thermal gravimetric analysis and X-ray Fluorescence diffractometer. The silver insertion in the zeolite did not change its structure. The antibacterial activity of the silver-substituted zeolite was performed by the minimum inhibitory concentration using Escherichia coli as target bacterium. The MIC of the zeolite with 1% silver and concentration of 0,05 mg zeolite/mL was not able to inhibit the visible growth of the bacterium, however, with the increase of the concentration there was total inhibition in the period of 24h. The contents of 5% and 10% showed MIC equal to 0,05 mg of zeolite/mL. The LDPE films added with silver-substituted zeolite A were synthesized by wet-casting. The zeolite mass content in the films ranged from 1% to 5% by mass. The films did not show significant changes in the thermal degradation profiles with the increase of the zeolita/Ag mass content present in the composite. The films with best antibacterial activity against Escherichia coli and Staphylococcus aureus were those prepared with 5% and 10% silver substituted zeolite and with a mass content of 5% (w/w), showing great potencial for applications such as active packaging in food preservation.

Thesis
1
  • JOSÉ ALBERTO BATISTA DA SILVA
  • BIODIESEL AND BIOLUBRICANTS PRODUCTION: ASSESSMENT OF NOVEL CATALYSTS AND NATURAL ANTIOXIDANTS

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • LEILA MARIA AGUILERA CAMPOS
  • LUCIENE DA SILVA SANTOS
  • MARITZA MONTOYA URBINA
  • TATIANA DE CAMPOS BICUDO
  • TIAGO PINHEIRO BRAGA
  • Data: Feb 18, 2019


  • Show Abstract
  • This research work was developed seeking the production of clean technologies and bioproducts with perspectives in industrial applications. For this purpose, several materials and bioproducts were obtained. The production of alternative silica (MP1) from the beach sand allowed to obtain mesoporous materials, MCM-41, as synthesized and modified, for several purposes, among these applications in CO2 adsorption processes, due to modifications with alkanolamines, MEA and DEA in addition to impregnation with metal cations, such as Ni+2, Zn+2 and Ag+, which allowed applications in deep desulphurization processes in petroleum derivatives. The chemical modification of MP1 with metals produced SKS bimetallic catalysts, successfully used in the synthesis of bioproducts such as biodiesel and biolubricants. All products were characterized by FTIR, TG / DTG, NMR, CG / MS, DRX, MEV-FEG, EDS, RANCIMAT, FRX, ICP-OES. Tests of reuse of the catalyst and studies on the conversion were carried out in order to obtain the best synthesis parameters. The bioproducts obtained obeyed the specifications of ANP 45/2014 for biodiesel and ANP 669/2017 for biolubricants. In order to optimize the use of the obtained bioproducts, natural antioxidants were obtained from the extracts of Syzygium aromaticum and Punica granatum and effectively tested in cotton biodiesel, to evaluate the effects produced in the oxidative stability of the biofuel.

2
  • ANA KARINA PEREIRA LEITE
  • MIXED LOFs AND NANOCOMPOSITES WITH ADSORPTIVE, PHOTOLUMINESCENT AND MAGNETIC PROPERTIES: FROM SYNTHESIS TO APPLICATION

  • Advisor : BRAULIO SILVA BARROS
  • COMMITTEE MEMBERS :
  • BRAULIO SILVA BARROS
  • DULCE MARIA DE ARAUJO MELO
  • LUCIENE DA SILVA SANTOS
  • RENATA MARTINS BRAGA
  • JARLEY FAGNER SILVA DO NASCIMENTO
  • JOANNA ELZBIETA KULESZA
  • Data: Feb 20, 2019


  • Show Abstract
  • The LOFs (Lanthanide-Organic Frameworks) have emerged as an important class of functional materials. These materials present interesting optical and magnetic properties, which are directly related to the presence of lanthanide ions connected by organic binders in a hybrid crystal network. More recently, these properties have been extended by combining with other types of materials of interest, or in other words by the formation of composites or derived materials. Among the vast possibilities, the combination of porous and / or luminescent materials with magnetite, which presents interesting magnetic properties, has been considered as promising for the sensing and the selective adsorption of organic chemical compounds besides other possibilities. In this work, mixed LOFs and Fe3O4/LOF nanocomposites were synthesized by solvothermic and hydro(solvo)thermal methods using lanthanide ions (La3+, Tb3+, Gd3+, Eu3+) and polytopic organic binders. The samples were characterized by XRD, IR, TG, MEV, photoluminescence spectroscopy and evaluated as chemical sensors for metals (Pb3+,Cd3 + and Li3+), as well as the selective adsorption of organic dyes. The results suggest that the use of a growth promoter, acetic acid, used to control the particle morphology, promoted the formation of an unexpected structure, where the lanthanide ions (La3+ and Tb3+) are coordinated to formate ions in a network three-dimensional, rather than isophthalic linker, as expected. Formate ions were formed from the hydrolysis of the solvent used, dimethylformamide (DMF). The crystallized samples are isoreticular with a structure already reported in the literature and of formula [Ce(HCOO)3]n. The IR spectra exhibited the displacement of the stretch related to the carbonyl group of the ion format. The Tb3 + ion was incorporated into the structure giving green luminescence. The morphology of powders changed from micro stems to agglomerates of small flower-like particles when the concentration of acetic acid was increased. LOFs prepared with the lanthanide ions (Gd3+ and Eu3+) and the binder precursor, 1,3,5-benzene tricarboxylic acid (BTC). The results of XRD confirmed the crystallization of an isoestructure of LOF [Gd(BTC)(H2O)](DMF)(H2O)0.5, while IV results suggest the deprotonation of the carboxyl group of the ligand and its coordination to the ion Gd3+. The red luminescence of the compound when excited in the ultraviolet region confirmed the incorporation of Eu3+ ions. Nanocomposites (Gd, Eu) -LOF/ Fe3O4 were prepared under solvothermic conditions. The results of XRD confirmed the formation of the mixed LOF at the same time that characteristic diffraction peaks of the magnetite were observed, which was also confirmed by the magnetic characteristic of the obtained samples. The analysis of IV confirmed the deprotonation of the carboxyl group of the ligand and its coordination to the Gd3+ ion, also a 560 cm-1 band was observed regarding the Fe-O stretch of the magnetite. In addition, the composite also showed red luminescence characteristic of the europium ion. The results of the tests as a chemical sensor showed that the LOF presents a satisfactory result for the Pb3+ ion. Selective adsorption tests of the dyes using the composite and LOF show that the composite adsorbs more methylene blue (98%) than methyl orange (35%) at a concentration of 70mg/L for a time of 2h.

3
  • OLÍMPIO JOSÉ DA SILVA JÚNIOR
  • COORDINATION POLYMERS AND THEIR DERIVED OXIDES: FROM THE PREPARATION TO APPLICATION IN THE DECOLORIZATION OF WATER CONTAMINATED WITH ORGANICS DYES

  • Advisor : BRAULIO SILVA BARROS
  • COMMITTEE MEMBERS :
  • BRAULIO SILVA BARROS
  • CLEONILSON MAFRA BARBOSA
  • DAVI SERRADELLA VIEIRA
  • ELANIA MARIA FERNANDES SILVA
  • JOANNA ELZBIETA KULESZA
  • Data: Feb 20, 2019


  • Show Abstract
  • Coordination polymers (CP) are a new class of hybrid materials consisting of metal species or clusters connected by organic linkers and forming structures along one, two or three dimensions. In this research, we propose the use of CPs and their derived oxides in the discoloration of water contaminated with organic dyes. Three Cu2+ coordination polymers were prepared by an electrochemical method using the following linkers: 1,3-H2BDC, 1,4-H2BDC, and 5-NH2-H2BDC. The samples obtained were calcined in air at 923 K yielding porous CuO. The synthesis of Ca-MOFs was performed using a sonochemical method. The main synthetic parameters were studied, and the factorial planning was employed to reduce the total number of samples produced. All the prepared samples were characterized by X-ray powder diffraction (PXRD), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (ATR-FTIR), Thermal Analysis (TGA-DTA) and Scanning Electron Microscopy (SEM). The results confirmed both the crystallization of the Cu2+ coordination polymers and the formation of the copper oxide after the heat treatment. The porous CuO was tested for the catalytic degradation of methylene blue in the presence of H2O2, and the effect of reaction parameters such as catalyst mass and H2O2 volume were studied. The optimum reaction conditions were established, with discoloration reaching about 94 and 100% at 308 and 311 K, respectively, after only 120 minutes of reaction. The Ca-MOFs samples were applied in the adsorption of the methylene blue dye at natural pH, obtaining maximum adsorption of 60.241 μmol.g-1 and high efficiency in the reuse, reaching 97% of the initial adsorption capacity in the second reuse cycle. The results suggest that the presence of the [Ca(BDC)(DMF)(H2O)] phase does not increase the adsorption capacity when compared to the other crystalline phase obtained, [Ca(BDC)(H2O)3]n. Both materials have been shown to be promising in the discoloration of contaminated water.

4
  • ANDERSON FERNANDES GOMES
  • EVALUATION OF THE POTENTIAL OF MICROALGAE Chlamydomonas sp. CULTIVATED IN AN OPEN SYSTEM AS A SOURCE OF HIGH VALUE METABOLITES WITH APPLICATIONS INTEGRATED TO THE BIOFUELS SECTOR, AIMING AT A BIOREFINERY PERSPECTIVE

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • LUCIENE DA SILVA SANTOS
  • ANTONIO SOUZA DE ARAUJO
  • MARTA COSTA
  • NEDJA SUELY FERNANDES
  • LEANDRO SILVA COSTA
  • MARIANA SANTANA SANTOS PEREIRA DA COSTA
  • Data: Feb 28, 2019


  • Show Abstract
  • Nowadays it is relevant that the processing of any large-scale raw material occurs in a biorefinery design, which consists in optimize the use of resources, aiming at maximizing profitability, benefits and minimizing waste generation. Considering this context, microalgae present high biorrefinario potential, since they exhibit numerous constituents with high value. The microalgae, when subjected to nutrient restriction conditions, become susceptable to the accumulation of total lipids and changes in the fatty profile. In this study, the microalgae Chlamydomonas sp. was cultivated in photosynthetic ponds and submitted to the absence of nutrients. Subsequently, the extraction efficiency of the crude hexanic lipid fraction (CHF), using mechanical agitation associated with the ultrasound technique, was evaluated in two different times (2 and 4 hours). In addition, the biomass before the extractive process (BBE), as well as the residual biomasses from the hexane fraction (RBHF2h and RBHF4h) were monitored by SEM and Thermogravimetric Analysis (TG). Crude protein and high heating value (HHV) were estimated as a function of the elemental composition of biomasses RBHF2h and RBHF4h. Crude chloroform fraction (CCF) was obtained from RBHF4h (extraction with chloroform). The CCF and CHF fractions after hydroesterification were characterized by TG, FTIR and GC/MS. Besides, the crude methanolic extract (CEM) was obtained from CTG biomass with ultrasound as cell rupture system and after that the fraction was characterized by GC/MS. It´s worth pointing out that the CEM over the cell viability of murine melanoma tumor cell line B16F10 and normal line of murine fibroblast 3T3 were evaluated as for the reduction capacity of MTT reagent. Moreover, immunosuppressive potential was also analyzed in macrophags RAW 264.7 model concerning its capacity of nitric oxide production (NO). Surface micrographs of the biomass showed greater fragmentation for RBHF4h, as well as a significant reduction in the typical thermal event of lipids (350-470 °C), indicating extraction efficiency and correlation with the significant difference (greater than 300%) of the obtained CHF at different times. The maximum total lipid fraction (CHF + CCF) was approximately 29%, 60% higher than the control group (CTG). Residual biomasses have HHV and crude protein values at about 19 MJ kg-1 and above 50%, respectively. The TG and FTIR data presume the predominant composition of saponifiable fractions for the CCF extract, unlike the CHF which is composed especially of unsaponifiables. In addition, the TG curve ratified a better conversion rate for CCF (approximately 89%), consistent with the value obtained by GC/MS (about 86%). The fatty profile of the saponifiable fractions of both extracts showed that fatty acids are mostly composed of C16:0 and C18:3 (ω-3 and ω-6). Another important aspect, and that the stress condition induced a percentage increase of C18:3, however, significantly reduced the C18:2 content when compared to CTG. It is worth mentioning that although the esters exhibit a high concentration of polyunsaturated fatty acids, which compromises their application in the production of biodiesel, the fatty profile of microalgae suggests a pharmacological potential for diet or therapy, since some of the main components are reported as bioactive metabolites. While residual biomass could potentially be targeted to aquaculture (nutritional supplementation) in the face of significant protein content, or for direct combustion due to high value HHV. GC/MS data revealed that CEM composition is mostly of squalene (isoprenoid), phytol (acyclic diterpene alcohol) and adipic acid bis(2-ethylhexyl) ester. The cell viability test revealed that the CEM extract promoted an considerable statistically decrease in the capacity of MTT reduction of B16F10 cell line, over 50%, while any effect over the normal cell line was observed, both until 400 µg mL-1. Besides, the methanolic extract showed notable inhibitory action on NO production by RAW machophages, promoting a reduction to upper 60% in comparison to positive control (LPS). Therefore, it is possible to infer that the polar extract of microalgal biomass presentes substances with inhibitory potential regarding the viability of câncer cells, as well as the production of inflammatory mediator (NO).

5
  • BRENO GUSTAVO PORFIRIO BEZERRA
  • MATERIAL COMPOSITION BASED ON HDL AND ZEOLITE A FOR THE SIMULTANEOUS REMOVAL OF ANIONS AND CACTIONS FROM THE EFFLUENT OF THE OIL INDUSTRY

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • FABIO GARCIA PENHA
  • LINDIANE BIESEKI
  • LUZIA PATRICIA FERNANDES DE CARVALHO GALVAO
  • NEDJA SUELY FERNANDES
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Mar 14, 2019


  • Show Abstract
  • The water produced is extracted together with the oil and represents the largest waste stream in the production of crude oil. The aspects that deserve attention are its high volumes and the complexity of its composition. Disposal of such waste volumes has raised concerns about uncontrolled environmental pollution and is irreversible in the marine environment.

    So the removal of these contaminants is considered a major problem, a challenge in the world today, but can be seen as an opportunity to provide a viable source of water, as beneficial in many applications, for which the quality of drinking water is not avoiding serious environmental damage. Thus the development of technologies through the adsorption of cations and anions is efficient and simple and has been used in for the remediation of waters and effluents.

    In this work, treatments were carried out in water produced through the adsorbent commercial zeolite A, through a planning in which its adsorption capacity was compared as a function of the contact time with the produced water, in periods of 0 (without treatment) to 24 hours , at the end of the treatment, the samples were analyzed by ICP-OES. Also, different materials such as zeolites, aluminas and Lamellar Double Hydroxides were used. It was observed that for zeolite materials A, ɣAl2O3 and calcined commercial HDL were the most satisfactory results with a percentage of 60% to 99% of removal and when compared to the maximum permissible values established by Resolution No. 430 of the National Council of the Environment Environment, and finally the synthesis of a new composite material based on Zeolite A and HDL, being a material with specific properties for the simultaneous removal of cations and anions, being efficient for remanage in petroleum produced water.

     

6
  • CAMILA CARVALHO DE ALMEIDA
  • DEVELOPMENT OF ELECTROCHEMICAL AND COMBINED PROCESSES FOR THE REMEDIATION OF EFFLUENTS AND SOILS CONTAMINATED WITH ORGANOHALOGEN COMPOUNDS

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DJALMA RIBEIRO DA SILVA
  • DOUGLAS DO NASCIMENTO SILVA
  • DANYELLE MEDEIROS DE ARAUJO
  • MARCO ANTONIO QUIROZ ALFARO
  • Data: Mar 18, 2019


  • Show Abstract
  • The growing concern of society with environmental risks and public health has required a more rigorous control of our waters and soil, promoting the development and implementation of new treatment technologies. Therefore, the present aimed to evaluate the decontamination of Persistent Organic Pollutants (POPs), specifically organohalogenated dye and pesticide, in effluents and soil by means of the integration of electrochemical processes using Boron Doped Diamond (BDD) anodes with other technologies of high efficiency and low environmental impact. The results of electrolysis with BDD anodes of a synthetic effluent contaminated with the Bromophenol blue textile dye clearly demonstrated that the application of different current values (1A, 2A, and 3A) was shown to be quite efficient because it not only reduces the color of the effluent, as well as lead to its complete mineralization. The significant concentration of Br- released during the attack of the OH radical on the dye and the formation of the BrO- species generated from the Anodic Oxidation of these anions explain the optimal performance of this technology in the treatment of synthetic solutions. The studies involving the decontamination of soil contaminated with the herbicide Clopiralida showed that it is possible to combine the dechlorination process with Zero Valent Iron (ZVI), soil washing and electrochemical oxidation in a single treatment sequentially or integrated in the same reactor. Therefore, Clopyralide was efficiently removed from the soil, and complete degradation of the pollutants in the wash fluids was possible using anodic oxidation with BDD electrodes in all studies. The dechlorination with ZVI integrated into the washing process has an important impact on the efficiency of the process, leading to less hazardous waste (from the point of view of toxicity), but at the same time the intermediates formed are less oxidizable than the initial chlorinated compounds, which results in a less efficient process from the point of view of mineralization. This negative impact on the efficiency of the electrochemical process is not completely undesirable, because as the toxicity of the residues decreases significantly in the initial stages with the use of iron, it becomes promising the combination of this technology with biological treatments.

7
  • RAILSON CARLOS SOUZA DA LUZ
  • INFLUENCE OF POLYELECTROLYTE COMPLEXES OF CHITOSAN-XANTHAN GUM WITH NANOSILICA IN THE              TECHNOLOGICAL PROPERTIES OF AQUEOUS DRILLING FLUIDS

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • FABÍOLA DIAS DA SILVA CURBELO
  • JULIANA DE SOUZA NUNES
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • LUZIA PATRICIA FERNANDES DE CARVALHO GALVAO
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Apr 15, 2019


  • Show Abstract
  • The incorporation of inorganic nanomaterials into polymer chains leads to the formation of new materials with specific characteristics and different from those presented by the originating materials. These materials are referred to as polymeric hybrid materials. The incorporation of nanosilica into the polymer chains of chitosan in the formation of the hybrid material of nanosilica-chitosan was the initial target of this work, being observed a significant influence of the process of obtaining, in the thermal properties and in the behavior in aqueous medium of these materials. The nanosilica-chitosan hybrid materials were also used as precursors in the formation of polyelectrolyte complexes, with the use of xanthan gum as polyanion, which, according to the results obtained from the viscoelastic behavior, provide the formation of a more structured three-dimensional network, when compared to the polyelectrolyte complex composed only of xanthan gum and chitosan. Both materials were applied in aqueous drilling fluids, providing an increase in apparent viscosity, which promotes the entrainment of gravel produced during the drilling of oil wells, providing the same cleaning efficiency. In relation to the filtration control of the drilling systems, the hybrid materials of nanosilica-chitosan presented reduction of the filtrate volume due to the formation of a less permeable filter cake. Similar result was also observed at high temperature (90 oC). In turn, the polyelectrolyte complexes presented similar behavior to the hybrid materials, that is low filter loss.

8
  • MARCUS VINICIUS GOMES PAIXÃO
  • EVALUATION OF THE POTENTIAL OF MAGNETIC/THERMORESPONSIVE CHITOSAN MICROSPHERES DECORATED WITH POLY (N-isopropylacrylamide) IN OILY WATER TREATMENT

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • JOSE LUIS CARDOZO FONSECA
  • JULIANA DE SOUZA NUNES
  • LUZIA PATRICIA FERNANDES DE CARVALHO GALVAO
  • MARCOS ANTONIO VILLETTI
  • ROSANGELA DE CARVALHO BALABAN
  • Data: May 17, 2019


  • Show Abstract
  • Smart microspheres capable of responding to magnetic fields and temperature changes were prepared by encapsulating magnetic nanoparticles into cross-linked chitosan microspheres followed by poly(N-isopropylacrylamide) (PNIPAM) brushes formation on their surfaces (MCM-PNIPAM). The synthetized microspheres were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermogravimetry (TG) and differential scanning calorimetry (DSC). While most studies have focused on the graft copolymerization reaction between chitosan and NIPAM to get a soluble particle, the main finding of this study was to improve the lipophilicity of magnetic crosslinked chitosan microspheres with PNIPAM brushes, in order to be used in oily water treatment as a solid adsorbent. In addition, we applied MCM-PNIPAM associated to PNIPAM homopolymer in an oil removal process. Commonly, oily water composition from an oil well is characterized by high salinity and high oil content. Therefore, it was investigated in this paper the PNIPAM thermoresponsive behavior in presence of salts (NaCl and CaCl2), as well as the oil removal efficiency due to the MCM-PNIPAM particles clustering effect above the aggregation temperature of PNIPAM. The thermoresponsive behavior of MCM-PNIPAM was confirmed by the sharp transition phase on DSC curves. The initial investigation of oil removal efficiency was performed to the synthesized microspheres with values higher than 97% for MCM-PNIPAM above the PNIPAM aggregation temperature. On the other hand, the results showed that the time is an important parameter to obtain higher oil removal mainly due to the salinity effect, and the presence of PNIPAM homopolymer chains can give significant advantages compared to the performance of individual MCM-PNIPAM microspheres.

9
  • JOÃO LEONARDO FREITAS OLIVEIRA
  • KINETICS AND PYROLYSIS OF LICURI OIL (Syagrus coronata) USING SODIUM / ACID VERMICULITE WITH ZINC OXIDE TO OBTAIN BIO-OIL

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • DJALMA RIBEIRO DA SILVA
  • ARUZZA MABEL DE MORAIS ARAUJO
  • EDJANE FABIULA BURITI DA SILVA
  • MEIRY GLÁUCIA FREIRE RODRIGUES
  • Data: Jun 27, 2019


  • Show Abstract
  • The application of clays has become more common in several areas of research in the last decades, thanks to its unique properties, be it in its pure form or modified physically / chemically. In this work, the natural and acidic vermiculite were used as catalysts and catalytic support for zinc oxide, in order to obtain promising catalysts for application in the pyrolysis of oleaginous plant origin known as licuri (Syagrus coronata). In all, five catalysts were synthesized, zinc oxide (ZnO), vermiculite supported with zinc oxide in the mass percentages of 1 and 6% (VZn1 and VZn6), vermiculite (V) and acid vermiculite with 1% and 6% of zinc oxide, VaZn1 and VaZn6, respectively. The catalysts under study were characterized by the following techniques: X-ray diffractometry (XRD), thermogravimetric analysis (TGA), nitrogen adsorption / desorption, scanning electron microscopy (SEM) and X-ray fluorescence (FRX). The pyrolysis tests for the determination of activation energy were performed on a thermogravimetric scale following Kissinger-Akahira-Sunose (KAS) and Ozawa Flynn-Wall (OFW) kinetic models. Rapid pyrolysis was performed using a Py-CG / MS for separation and determination of the bio-oil composition. In the kinetic study of the pyrolysis of the liqueur oil, the catalysts that showed the highest catalytic activity were V, VZn1 and VaZn1, presenting activation energy lower than the thermal pyrolysis of the oil from the 10% conversion. VZn1 and VaZn1 presented higher activity for the formation of hydrocarbons by deoxygenation of the oil, showing that the zinc oxide associated with vermiculite presents as an alternative option there are conventional catalysts for studies in the area of pyrolysis and production of bio- oil.

10
  • JANIELE MAYARA FERREIRA DE ALMEIDA
  • SYNTHESIS AND CHARACTERIZATION OF SILICA NANOPARTICLES OBTAINED FROM EXPANDED PERLITE FOR APPLICATION IN THE PH-RESPONSIVE RELEASE OF DRUGS

  • Advisor : NEDJA SUELY FERNANDES
  • COMMITTEE MEMBERS :
  • JOÃO AUGUSTO OSHIRO JUNIOR
  • BOLIVAR PONCIANO GOULART DE LIMA DAMASCENO
  • LOURENA MAFRA VERISSIMO
  • MARCIA RODRIGUES PEREIRA
  • NEDJA SUELY FERNANDES
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Jun 28, 2019


  • Show Abstract
  • Drug delivery systems whose performance depends on external conditions such as pH are called pH-dependent or pH-responsive. They are materials capable of promoting prolonged and / or specific drug delivery. Silica nanoparticles (NPS) are excellent materials for application as pH-responsive systems, since their surface is abundant in silanols (Si-OH) groups, which are highly sensitive to variations in pH. Isoniazid (INH) is one of the first-line tuberculostatics for long treatment periods. Part of INH degrades in very acidic media such as stomach pH, impairing the treatment of tuberculosis and requiring high daily doses to maintain the therapeutic effect. Topiramate (TPM) is a potent antiepileptic, used in high daily dosages since it has low bioavailability. In this context, NPS were used as inorganic matrices for the in vitro release of TPM and INH. The synthesis of NPS was made using a natural source of silica as a precursor (the expanded perlite, a natural, low cost and abundant aluminosilicate), by a fast, simple and without many apparatus. The synthesis parameters by Stöber method (sol-gel process), were varied obtaining particles of different sizes and size distribution (monomodal and bimodal). NPS were characterized by XRD, FTIR, SEM, DLS and zeta potential. They presented amorphous structure and spherical morphology. A methodology for the detection and quantification of TPM by GC-MS was developed and validated (following ANVISA, RDC 166 of 2017), replacing the standard technique of HPLC-MS, since the TPM can not be detected by spectrophotometric techniques. The drugs were incorporated in the NPS under optimized conditions by experimental design (factorial, 2n) by different methods: INH by adsorption and melt-loading TPM. The incorporation of the TPM brought a new methodology for the preparation of carriers using a thermogravimetric (TG) system of great temperature control in a thermobalance. The drug release study was done using dissolution media simulating the gastrointestinal pH: pH 1.2 (stomach), pH 6.8 and 7.4 (intestine). The duration of the assay followed the estimated time of gastrointestinal transit that an oral solid pharmaceutical form faces upon ingestion. The release profile showed that NPS presented a pH-responsive surface (greater release at pH 7.4) and with prolonged release of the drugs (8 hours for INH and 5 hours for TPM). The kinetic study evaluated the zero order, first order and Higuchi models for drug release in NPS, and the zero order model was the one that presented the best fit, confirming the aforementioned release profile. This greater release in intestinal pH guarantees a lower degradability in the acidic environment (stomach), greater absorption and efficiency of the drugs.

11
  • MARIA DE FÁTIMA ROCHA DE LIMA
  • CHEMICAL AND BIOLOGICAL PROSPECTION OF CAATINGA SPECIES: Euphorbia tirucalli, Bredemeyera floribunda and Bredemeyera brevifolia.

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • JOSEAN FECHINE TAVARES
  • LEANDRO DE SANTIS FERREIRA
  • MAIRA CONCEIÇÃO JERONIMO DE SOUZA LIMA
  • MATHEUS DE FREITAS FERNANDES PEDROSA
  • RENATA MENDONÇA ARAUJO
  • Data: Jun 28, 2019


  • Show Abstract
  • The Caatinga biome of the Brazilian Northeast constitutes an important potential of vegetal formation, since innumerable of its species are reported in the literature by the broad spectrum of biological activities and chemical diversity. Due to the potential of this biome, the present study approaches the chemical and biological investigation of three species of the caatinga, Euphorbia tirucalli Linn., Bredemeyera floribunda Willd. and Bredemeyera brevifolia Benth. The LC-MS analysis applied to the crude extracts of the three species allowed to evaluate the phytochemical profile of each species, in which it was possible to verify that the flavonoids represent the major class of secondary metabolites. The chemical study of the extracts hexane and ethanois of the shoots and roots (ETPAE-H, ETPAE-E, ETR-H and ETR-E) of the species E. tirucalli, using chromatographic techniques (adsorption and exclusion) allowed the isolation of five constituents and the evaluation of its antioxidant and antimicrobial activities. The hexane extract from the aerial part was initially subjected to a saponification reaction and the unsaponifiable constituents obtained were applied to a flash chromatographic column. This procedure allowed the isolation of a pentacyclic triterpene, β-amyrin (ET-1), already isolated in the species. As for the ethanol extract from the root, it was possible to isolate four substances through adsorption and molecular exclusion chromatography: sorbic acid (ET-2), apelopsin (ET-3), myricetin and 3,3 ' -dimethoxy-4'-hydroxy-4-pyran-raminose, both reported for the first time in the E. tirucalli species. As a continuation of this study, the antioxidant activity of the four extracts and compounds isolated from the radicals DPPH and ABTS was evaluated, which allowed to verify that the ethanol extract from the roots presented better efficiency compared to the two radicals with IC50 of 78,27 and 221,22 μg / ml against DPPH and ABTS radicals, respectively. For the isolated compounds, it was observed that the ET-4 compound showed significant inhibition of IC 50 free radicals of 22.62 μg / mL for DPPH and 53.22 μg / mL for ABTS, thus showing higher efficiency than the Trolox standard which presented IC50 of 49.12 μg / mL for DPPH and 112.15 μg / mL for ABTS. With respect to the antimicrobial activities it was possible to verify that only the ethanolic extracts were identified as potential antibacterial and antifungal agents for inhibiting the growth or killing of strains of bacteria and fungi such as S. aureus, E. coli, S. brasiliensis and C. Albicans. Among the compounds isolated, all showed inhibitory effect against strains of bacteria and fungi, with greater effect for ET-3 and ET-4 compounds. ET-3 showed high potential against S. aureus, E. coli and C. albicans with MIC = 8 μg / mL, 16 μg / mL and 32 μg / mL, respectively. And the ET-4 compound presented MIC of 8 μg / mL and CBM of 16 μg / mL against E. coli, showing more efficacy than the antibiotic Tetracycline. The chemical study of the species of the genus Bredemeyera was also promising, since from successive chromatographic treatments (adsorption and exclusion) applied to the hydroalcoholic extract of the roots of the species B. floribunda allowed the isolation of a cinnamic derivative, (2E) -3 '- (3,4,5-trimethoxyphenyl) prop-2-enoate, and a trimethoxylated xanthone, to 1,7-dihydroxy-3,4,8-trimethoxyxanthone both already isolated in that species. The chromatographic fractionation applied to the ethanol extract of the stems also allowed the isolation of three flavonoids, canferol and quercetin, both isolated for the first time in the species, and rutin, a molecule previously isolated in the roots of this species. The hydroalcoholic extract of the roots of B. brevifolia was initially submitted to liquid-liquid partition with hexane, chloroform and ethyl acetate. The chloroform fraction (BBEA-C) was applied to adsorption chromatography allowing the identification of two flavones, 5,7,4'-trihydroxy-3'-methoxyflavone and 5,7,2 ', 3', 4'- pentahydroxy-6,4'-dimethoxyflavone (BBR-1). The acetate fraction (BBREA-Ac) was first subjected to Sephadex LH-20 chromatography, and then, flash chromatography on silica gel, these procedures allowed the isolation of flavone 5,7,4'-trihydroxy-3'- methoxyflavone (BBR-2) identified in the chloroform fraction. The evaluation of the hyaluronidase activity showed that the B. jararaca venom was totally inhibited by the hydroalcoholic extract of B. brevifolia roots, in a ratio of 1: 5 (venom: extract, w / w). The characterization and structural elucidation of the compounds reported here were performed by analyzing the Uni and bidimention 1H and 13C Nuclear Magnetic Resonance Spectroscopy data as well as by comparison with literature data.

12
  • ANALLICY SANTOS DE PAIVA
  • Iron and manganese complexes with Schiff salen base derivatives and carboxylates ligands

  • Advisor : FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • COMMITTEE MEMBERS :
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANIEL DE LIMA PONTES
  • DANYELLE MEDEIROS DE ARAUJO
  • ULISANDRA RIBEIRO DE LIMA
  • Data: Jun 28, 2019


  • Show Abstract
  • Salen-type complexes are an important class of coordination compounds, with the intention of continuing to investigate this ligand in new complexes, this present work has the objective to synthesize new iron-(III) and manganese-(III) complexes containing as main ligand the salen base Schiff derivaties, 3-MeOsalen or 3-MeOsalophen, and the salicylate and biphthalate carboxylate ligands as auxiliaries. The synthesized ligands, precursors complexes and the novel synthesized carboxylate complexes were characterized by spectroscopic techniques (Vibrational spectroscopy in the infrared region, Raman Spectroscopy,   Electronic spectroscopy in the ultraviolet and visible region and fluorescence), electrochemistry (cyclic voltammetry) and thermal analysis (Thermogravimetry). The complexes presented asymmetric and symmetrical vibrational modes of the carboxylate group, for salicylates,  observed in 1570 cm-1asCO2-) and 1370 cm-1sCO2- ) while  the spectra of the complexes with biphthalate, the υasCO2- were observed in around 1700 cm-1 and υsCO2- around 1350 cm-1. By the variation of these stretches, the ligands are coordinated in bidentent form by oxygen from different groups. In relation to the electronic spectra for the carboxylate iron complexes, bathochromic displacement of the LMCT charge transfer band was verified and in the manganese complexes changes in the d-d bands were observed, having as reference the respective precursor complexes. These changes were due to substitution of the chloride ligand by the carboxylate ligand. In the emission spectra of the iron complexes with 3-MeOsalophen ligand, they presented an emission band around 480 nm. In the voltamograms of the complexes was observed a metal redox pair Fe3+/Fe2+ ou Mn3+/Mn2+ and processes related to the Schiff base. In replacing the chloride ligand by the carboxylate caused an increase in difference of the cathodic potential and the anodic potential of the metal. In the TG and DTG curves have been observed the decomposition of the carboxylate ligand at around 262°C and the other two losses attributed to Schiff's base.

13
  • GEOVANE CHACON DE CARVALHO
  • COMPOSITION OF FATTY ACIDS IN VEGETABLE OILS OBTAINED BY GAS CHROMATOGRAPHY AND ITS CORRELATION WITH THERMAL, RHEOLOGICAL, SPECTROSCOPIC AND OTHER PHYSICO-CHEMICAL PROPERTIES

  • Advisor : MARIA DE FATIMA VITORIA DE MOURA
  • COMMITTEE MEMBERS :
  • MARIA DE FATIMA VITORIA DE MOURA
  • RENATA MENDONÇA ARAUJO
  • JAILSON VIEIRA DE MELO
  • LIVIA PAULIA DIAS RIBEIRO
  • MARTA CÉLIA DANTAS SILVA
  • Data: Jul 17, 2019


  • Show Abstract
  • This work determined the acidity index (IA), saponification (IS), peroxide (IP), iodine (II), refraction (IR), relative density (d), viscosity (ƞ), composition and acid distribution (OR), cacay (OC), quinoa (OQ), green coffee (OCV), jamelão (OJ), and moringa extracted from the fruit of the annatto (OR), according to the Association of Official Analytical Chemists of seeds and leaves and flowers, respectively WHO and OMFF. It performed the thermal characterization using thermogravimetry and calorimetry. The volatiles released during their thermal decomposition by TG-FTIR and a rheological study were analyzed. From the rheological study, the following order OR> OC> OJ> OCV> OMS> OQ> OMFF was obtained for activation energy (Ea). From the TG / DTG / DSC curves obtained, it was verified that each analyzed oil had peculiarities in its thermal decomposition, the order of stability proposed through TG / DTG is OQ> OMFF> OCV> OMS> OJ> OC> OU. From the infrared spectra it was possible to observe the evolution of the volatiles during the thermal decomposition, in the atmospheres of synthetic air and N2, of the different oils. It has been found that each oil has different intensities in the thermal decomposition products. It was observed that the products of the decomposition of the studied oils presented the same profile during their thermal decompositions, it is concluded that there is a pattern in the thermal decomposition of these oils with products of similar decomposition. Chromatograms indicated the presence of 13 fatty acids with linoleic acid (C18: 2n6c) being the most abundant fatty acid in all samples. The OMFF sample presented higher content of unsaturated fatty acids while the OJ sample presented higher content of saturated fatty acids.

14
  • ÁDILA PRISCILLA GOMES RODRIGUES
  • SYNTHESIS AND CHARACTERIZATION OF DOUBLE PEROVSKITES WITH STOICHIOMETRY La2CrBO6 WITH B = Fe, Co AND Ni - DETERMINATION OF THEIR MAGNETIC PROPERTIES

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • BRAULIO SILVA BARROS
  • DULCE MARIA DE ARAUJO MELO
  • JOANNA ELZBIETA KULESZA
  • JOSE HUMBERTO DE ARAUJO
  • RENATA MARTINS BRAGA
  • Data: Jul 22, 2019


  • Show Abstract
  • The metal oxides have various interesting physical properties ranging from, for example, ferroelectricity, colossal magnetoresistance until superconductivity, occupying therefore an outstanding position in the modern technological stage. The perovskite structure is the basis of a large number of oxides containing transition metals that exhibit these varied physical properties. This work proposes to obtain and characterize double perovskite stoichiometry with La2CrB'O6 (B '= Co, Fe and Ni) and to study the effect of the transition metals Co, Fe and Ni in their magnetic properties. The materials were obtained by gelatin synthesis. The synthesis process by this method is novel and is a variation of the sol-gel method in which the alkoxide precursors are replaced by gelatin. This method has the advantage that gelatin is a low cost and non-toxic material. The method uses metal nitrates using commercial gelatin as an organic precursor. The synthesized material was characterized by X-ray diffraction (XRD) using the Rietveld refinement of the method, scanning electron microscopy (SEM) and their magnetic characteristics were obtained by Mossbauer spectroscopy and magnetization measurements. The results of the XRD, combined with the refinement, showed the formation of perovskite phases and secondary phases in all the samples. Hysteresis curves and magnetic measurements revealed different temperature dependent magnetism behaviors.

15
  • ISABEL DO NASCIMENTO SILVA
  • STUDY OF THE PHOTOCATALITIC DEGRADATION OF THE CAPTOPRIL DRUG BY THE COMPOSITE OF TiO2- EXPANDED PERLITE NANOPARTICLES

  • Advisor : NEDJA SUELY FERNANDES
  • COMMITTEE MEMBERS :
  • CLÁUDIA DE OLIVEIRA CUNHA
  • DJALMA RIBEIRO DA SILVA
  • ELISAMA VIEIRA DOS SANTOS
  • LIDIANE ALVES DE MORAIS
  • NEDJA SUELY FERNANDES
  • Data: Jul 23, 2019


  • Show Abstract
  • Concern over the inappropriate disposal of substances in the environment has been increasing in recent years. Emerging micropollutants have been causing great impact on nature. Among this class, drugs are highlighted because they are biologically active substances that are difficult to break down by conventional treatment systems. The Advanced Oxidative Processes (AOPs) can be used in the treatment of these pollutants, because it is an efficient technique in the mineralization of the contaminant. Among these methods, heterogeneous photocatalysis can be used, being characterized by the use of semiconductors as photocatalysts. The most used semiconductor in this process is TiO2, presenting good degradation efficiency. However, TiO2 can be easily dispersed making the aqueous medium separation process difficult, and needs to be supported on some material. In this work, expanded perlite (EP), an aluminosilicate of volcanic origin, was used as support material, thus obtaining a composite. The study was carried out with captopril (CAP), an antihypertensive, also characterized as teratogenic substance, and can cause several damages in fetuses. The synthesis of the composites was based on the methodology described in the literature. Initially tests were carried out to verify the adsorption equilibrium, in which 200 mL of CAP solution in 100 mg of composite was used in a photocatalytic reactor, without radiation. For the photocatalytic tests, the same conditions were maintained, however, using a 9 and 18 Watt lamps in the irradiation process, the same parameters being established for the photolysis tests without the use of the composite. The results show that the characterization techniques used in this study, IV, XRD, FRX, SEM, EDS and particle size analysis, showed that the TiO2 was incorporated in the EP matrix. The adsorption / desorption tests showed that the adsorption equilibrium time for the composites in the CAP drug solution was 30 minutes. The photolysis and photocatalysis tests indicated that the main effect between the two degradation methods is in relation to the time of analysis. There was degradation of 32.0% in 285 minutes for photocatalysis and 26.5% in the time of 450 minutes for photolysis at the concentration of 50 mg L-1. The percentages of degradation at the concentrations of 50, 40, 30, 20 and 10 mg L-1 were respectively for photolysis 26.5, 26.3, 26.1, 40.0 and 43.1% and for photocatalysis at the concentrations of 50, 40, 30, 20 and 10 mg L-1 were 32.0, 36.0, 38.3, 41.0% and 42.8%. Degradation to T-EP-30% and T-EP-10% composites showed that there was a reduction in the concentration of CAP of 18.5% for the T-EP-30% composite at 50 mg L-1 concentration in the time of 120 minutes and 33.7% for the concentration of 10 mg L-1 in the time of 90 minutes. For the T-EP-10% composite, there was a degradation of 26.3% in 240 minutes for the concentration of 50 mg L-1 and 32.7% for the concentration of 10 mg L-1 in the time of 120 minutes, indicating that the composite with higher TiO2 content was more effective in the degradation. The kinetic study showed that kinetics is governed by the Langmuir-Heinshelwood model. The kinetics of the system was obtained as being of first order. The toxicity tests showed that the CAP had a negative influence on the germination and growth of the Lactuca sativa seeds, but the treated effluents showed a similar performance to the positive control. The increase of the radiation intensity favors the degradation process, presenting better results for the composite T-EP-50% in the concentration of 10 mg L-1. The TOC analysis showed that the test with the concentration of 10 mg L-1 of CAP and with the composite T-EP-50% with power of radiation of 18 W had a better percentage of effluent mineralization, 39.8%. The energy cost study showed that the most economical process was for photocatalysis in the concentration of CAP of 10 mg L-1 in the power of radiation of 18 W and for the photolysis process in the concentration of CAP of 10 mg L-1 in the values of R $ 0.057 and 0.0962, respectively.

16
  • FERNANDA SAADNA LOPES DA COSTA
  • SPECTROSCOPIC METHODS AND MULTIVARIATE CLASSIFICATION APPLIED IN THE DIFFERENTIATION OF PATHOGENIC MICRO-ORGANISMS

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • EDGAR PERIN MORAES
  • FABRICIO GAVA MENEZES
  • JOSELIO MARIA GALVAO DE ARAUJO
  • KASSIO MICHELL GOMES DE LIMA
  • LUCIANO FARIAS DE ALMEIDA
  • SHERLAN GUIMARÃES LEMOS
  • Data: Jul 25, 2019


  • Show Abstract
  • This study demonstrates the development of multivariate classification methods, allied to spectroscopic techniques, such as spectroscopy in the medium infrared region and molecular fluorescence, in the detection of pathogenic microorganisms: fungi and bacteria. The first studies looked for the differentiation of Cryptococcus neoformans and Cryptococcus gatti. These fungi are the etiological agents of cryptococcosis, whose adequate treatment depends on the rapid and correct detection and differentiation of the species. This determination is currently made by classical and molecular techniques and is mostly laborious and expensive. As an alternative method to discriminate C. gattii and C. neoformans, the attenuated total reflectance average infrared spectroscopy, combined with multivariate classification techniques (PCA-LDA QDA, GA-LDA QDA, SPA-LDA/QDA ), in which the GA-QDA model obtained sensitivity in the classes C. neoformans and C. gatti of 84.4% and 89.3%, respectively, using only 17 wave numbers. Then, using fluorescence emission and excitation matrix (EEM) spectroscopy, combined with multivariate classification methods (UPCA-LDA/QDA, UGA-LDA/QDA, USPA-LDA/QDA, PARAFAC/PLS-DA, nPLS-DA). The most satisfactory model was UGA-LDA, which used only 5 wavelengths, and presented a sensitivity of 88.9% in calibration and 100.0% of prediction for both species, results that are comparable to routine biological tests. The last study, aimed at the differentiation of sensitive and multiresistant bacteria of the genus Klebsiella sp. and Escherichia coli. Through molecular fluorescence spectroscopy and multivariate classification methods: LDA, QDA and SVM, coupled to PCA, GA and SPA data reduction algorithms. Among these, the models that had the best performance for both bacterial genera were UPCA-QDA and UGA-SVM with 100% classification accuracy. Compared to classical methods, the methodologies proposed in these studies demonstrate an innovative, faster and cheaper alternative for the identification of pathogenic microorganisms, such as fungi and bacteria, opening up the possibility of being applied in routine diagnostic laboratories.

17
  • MOISÉS DA COSTA BORGES SOARES
  • OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE TO STYRENE IN PRESENCE OF CO2 OVER CoFe2O4-MCM-41 CATALYST: preferential adsorption on the O2-Fe3+O2- sites located at octahedral positions

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • ANTONINHO VALENTINI
  • MARCO ANDRE FRAGA
  • MIGUEL ANGELO FONSECA DE SOUZA
  • TIAGO PINHEIRO BRAGA
  • VALTER JOSE FERNANDES JUNIOR
  • Data: Jul 26, 2019


  • Show Abstract
  • The present study describes the catalytic performance of cobalt ferrite supported on MCM-41 for the oxidative dehydrogenation of ethylbenzene and evaluates the role of CO 2 on the surface of the catalyst during the reaction using experimental data and density functional theory (DFT) calculations. A mechanism has been described indicating the role of the O-2-Fe3+-O2- and O-2-Co2+-O2- acid-base sites present in the tetrahedral and octahedral positions of the cobalt ferrite structure. The solids were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), Mössbauer spectroscopy (MS), X-ray photoelectron spectroscopy (XPS), vibration-sample magnetometry (VSM), temperature-programmed reduction (H2-TPR), chemical adsorption of NO and pyridine followed by infrared (FTIR) analysis, temperature-programmed desorption of CO2 (TPD-CO2), N2 physisorption and transmission electron microscopy (TEM). The results of XRD, RS, MS and VSM, before and after catalytic tests, confirmed the formation of partially inverted cobalt ferrite and showed the role of CO2 in the reactivation of the acid-base sites during the catalytic cycle, observing that the ferrite phase of cobalt was maintained when the reaction was carried out in the presence of CO2 and reduced in the tests without CO2. N2 isotherms, low angle XRDs and TEM images showed the formation of MCM-41 support. The catalytic tests showed that CO2 is essential to obtain good conversion values of ethylbenzene and that cobalt ferrite is more active and stable than the traditional hematite catalyst. Thermogravimetric analyzes showed that CO2 favors the oxidation of deposited carbon during the reaction. The results of TPD-CO2 and FTIR-CO2 indicated the presence of weak basic sites and the preferential adsorption of CO2 as carbonate and bicarbonate bridges. The computational results confirmed the preferential form of CO2 adsorption as bicarbonate. The proposed catalytic cycle, through a theoretical approach (DFT), shows that the adsorption of CO2 and ethylbenzene occurs preferentially at the octahedral sites O-2-Fe3+-O2- - compared to the O-2-Co2+-O2- sites, due to to a higher acidity of the iron sites compared to cobalt on the surface of the spinel, evidencing the role of CO2 in regenerating lattice oxygen and the iron phase of the spinel. By approaching the surfaces of complementary electrostatic potential, the adsorption of ethylbenzene occurs preferentially at the outermost FeOX (x> 4) sites (Lewis acid) and the dehydrogenation reaction occurs predominantly in the oxygens bound to iron (Lewis base).

18
  • MARCELA DE CASTRO NOGUEIRA DINIZ PONTES
  • CHEMICAL AND BIOLOGICAL STUDY OF SPONGES Agelas sp. AND A. dispar FROM NORTHEAST OF BRAZIL

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • RENATA MENDONÇA ARAUJO
  • FABRICIO GAVA MENEZES
  • LEANDRO DE SANTIS FERREIRA
  • MARIA DE FÁTIMA VANDERLEI DE SOUZA
  • YANNA CAROLINA FERREIRA TELES
  • Data: Jul 26, 2019


  • Show Abstract
  • The genus of marine sponges Agelas is source of brominated pyrrole and imidazole alkaloids, terpene derivatives and sterols, many of them with amino acid moieties. Its metabolites are associated with biological activities useful to human being, such as antitumor, antihistaminic, antibacterial, antifungal, cytotoxic, calcium channel modulator and antiserotoninergic, among others. In this work, two extracts from Agelas collected on brazilian northeast coast were investigated. First, semi crude fractions from extract of Agelas dispar were tested in microbiological assay and demonstrated antibacterial action against eight bacterial strains, such as Staphylococcus aureus, Staphylococcus. epidermidis, Staphylococcus hominis, Enterococcus faecalis, Enterococcus faecium, Pseudomonas aeruginosa, Escherichia Coli and Salmonella enteriditis. The fraction derived from ethyl acetate showed higher antibacterial action, with MIC = 39.06 μg/ ml. The ethanol extract from another Agelas sponge and the antibacterial fractions from A. dispar were analyzed in HPLC-MS, and were identified the metabolites longamide B, methyl ester of longamide B, mukanadine A and E, clathramide A, oroidine, 4,5-dibromo-2-carboxamide, 4,5-dibromo-2-carboxylic acid, hanishine, 9,10 di-hydro-keramadine, dispacamide A and methyl-hymenidine through positive mode. Also were identified, by HPLC-MS negative mode, the compounds agesamide, dispacamide D, mauritamide D. The GC-MS analysis permitted identification of sterols and ester from fatty acids such as penta, hexa, hepta and octadecanoic, besides nonadecen, docosanol, tetracosanol, pentacosanol and heptacosanol, behenic acid, squalene and 2,4-terc-butyl-phenol, all obtained from the fractioning of lipid extracts. The substance 4-bromopyrrole-2-carboxamide were isolated. Fractionation and identification of the metabolites was achieved through classical chromatographic techniques, GC-MS, HPLC-MS and 1H and 13C uni and bidimensional NMR.

19
  • VALDIC LUIZ DA SILVA
  • APPLICATION OF MICROEMULSIFIED SYSTEMS AS CLEANUP FLUIDS, TO REMOVE FILTER CAKE FROM NON-AQUEOUS DRILLING FLUID

  • Advisor : ALCIDES DE OLIVEIRA WANDERLEY NETO
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • JOSE LUIS CARDOZO FONSECA
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • MARCOS ALLYSON FELIPE RODRIGUES
  • FABÍOLA DIAS DA SILVA CURBELO
  • MONICA RODRIGUES DE OLIVEIRA
  • Data: Jul 26, 2019


  • Show Abstract
  • Drilling fluids with specific purposes are used in the drilling of oil extraction wells, including the formation of a thin film of low permeability (filter cake) on the walls of the well. However removal of the plaster is necessary so that the cementation between the rock formation and the coating is efficient. The refore in this process wash fluids are known as "washers" that are intended to remove the filter cake formed by the drilling fluid. The use of microemulsion systems as a cleanup fluids have stood out, mainly by removing the nonaqueous drilling fluids and promoting the inversion of the wettability of the formation. In this context, this work developed and characterized microemulsion systems based on the construction of pseudo-diagrams formulated with cationic surfactants (DAC) and anionic (SDS) for use as a cleaning fluid  that was compatible and wettable to the cement- coating. The formulated microemulsion systems were characterized by the study of: plaster removal efficiency tests, reuse of efficient rendering systems, surface tension measurements, droplet diameter, solids and liquids content (drilling fluid), thermal stability (thermogravimetric curves T / G and DTG), rheology, compatibility, wettability and compressive strength (UCA). The results with cleanup fluids, formulated with cationic surfactant (DAC), provided 100% removal efficiency for direct and bicontinuous micelles, and 98.48% for reverse micelle when these fluids have a C / T ratio of 40% in their composition. DAC-16 cleaning fluid, which has the composition 11.6% C / T, 2.4% FO and 86% FA, removed 100% of rendering and improved the wettability of the rock to water and is compatible with the system. The systems formulated with anionic surfactant (SDS) provided 100% removal efficiency for direct, bicontinuous and reverse micelles for fluids with a C / T ratio of 40% in their composition. LC-7.7 fluid, 30% C / T composition, 10% F / O and 60% FA, removed 100% plaster, excellent wettability of the water formation and compatibility with the cement paste.

20
  • FERNANDA MARIA DE OLIVEIRA
  • CHEMOMETRIC TOOLS OF MULTIVARIATE CALIBRATION FOR MONITORING OF DIESEL OIL QUALITY

  • Advisor : LUCIENE DA SILVA SANTOS
  • COMMITTEE MEMBERS :
  • DAMILSON FERREIRA DOS SANTOS
  • JOAO FERNANDES DE SOUSA
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • LUCIENE DA SILVA SANTOS
  • PATRICIA MENDONCA PIMENTEL
  • Data: Jul 31, 2019


  • Show Abstract
  • Diesel oil is one of the main derivatives of petroleum, fundamental for the Brazilian road sector, in the transportation of passengers and cargo. The adulteration of this fuel, with low-cost products, such as vegetable oils and petrochemical solvents, is worrying, since it brings numerous damages, both financial and environmental. For the rapid identification of these changes in fuels, it is necessary to develop more practical and efficient methods applied to the monitoring of diesel quality and to the detection and quantification of adulterants. This work was developed with the aim of contributing to the repertoire of analytical techniques applied to the monitoring of diesel, using spectroscopic methods associated with chemometric techniques. This research was conducted using two types of approaches, the Multivariate Curve Resolution (ALCR) and Partial Least Squares (PLS), for the identification and quantification of residual vegetable oils added as adulterants in the commercialized diesel oil and the Artificial Neural Networks (ANNs) for determination of specification parameters of diesel oil. In the identification and quantification of the adulterant residual oil, 16 commercial samples of diesel containing 8% (v / v) biodiesel and 10 mg of sulfur / kg (denominated S10B8) were mixed with the residual frying oil at various volumetric concentrations (1 - 60%), and then determined their physicochemical properties specified by the National Agency for Petroleum Natural Gas and Biofuel - ANP (specific mass, kinematic viscosity, flash point and atmospheric distillation), according to American Society standards for Testing and Materials (ASTM). At the same time, infrared medium with Fourier transform, FT-MIR, and near infrared, FT-NIR, for the creation of multivariate calibration models. The two models created (MCR-NIR, MCR-MIR, PLS-NIR and PLS-MIR) were able to accurately predict, not presenting a statistical difference between the estimated concentrations of adulterant and the reference values, being valid for a confidence level of 95%. In addition, the MCR-ALS was able to recover the pure spectral profile related to fuels and adulterants. For the modeling of ANNs, 162 diesel samples of different compositions (50, 500 and 1800 mg kg-1) were used, thus revealing the variety of fuel in the Brazilian market, which were analyzed according to ASTM methodologies recommended by the ANP, with a total of 810 tests. The ANNs were used to predict, not simultaneously, flash point, cetane number and sulfur content (S1800) of diesel blends with 7% (v / v) biodiesel, using distillation curves (ASTM D86), specific mass (ASTM D405), cetane number (ASTM D4737), flash point (ASTM D93) and sulfur content (ASTM D4294) as input data for modeling. The low error values obtained in comparison to other chemometric models described in the literature and high correlation coefficients between the reference and predicted values showed that the ANNs were efficient in determining the flash point, cetane number / cetane number and sulfur (1800 mg kg-1). In addition, the proposed method presents advantages such as low cost and easy implementation, since it uses data of the own routine monitoring to evaluate the quality control of diesel.

21
  • LECH WALESA OLIVEIRA SOARES
  • DEVELOPMENT OF Pt-USY CATALYSTS TO IMPROVE CETANE NUMBER IN LOW QUALITY DIESEL FRACTIONS VIA SELECTIVE RING OPENING REACTION OF NAPHTHENIC COMPOUNDS

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • ANTONIO SOUZA DE ARAUJO
  • ELEDIR VITOR SOBRINHO
  • FABIO GARCIA PENHA
  • LUIZ ANTÔNIO MAGALHÃES PONTES
  • Data: Aug 15, 2019


  • Show Abstract
  • A challenging hot topic faced by the oil refinery industry is the upgrading of low-quality distillate fractions, such as LCO, in order to meet current quality standards for diesel fuels. Thereof, an auspicious technological alternative entails the complete saturation of the aromatic structures followed by the selective cleavage of endocyclic C-C bonds in the formed naphthenic rings (selective ring opening or SRO). This work reports the influence of metal incorporation method in bifunctional Pt-USY catalysts with the aim of maximizing the dispersion at relatively high metal loadings as a means of improving their performance for the SRO of decalin as a model feed. A Pt-USY catalyst displaying low density of Brønsted acid sites and nearly monoatomic Pt dispersion (98%) at 4.9 wt% loading was prepared at optimized preparation conditions. This catalyst exhibited an outstanding performance in the SRO of decalin, giving a maximum combined yield to selective ring opening products (ROP: C 10 – alkylcycloalkanes + OCD: C 10 -alkanes) as high as 50% with a high proportion of the so-called open chain decanes (OCD) bearing the highest cetane. High (hydro) thermal stability and secondary mesoporosity of the Pt-USY catalysts make these systems highly prospective for upgrading low-quality distillate feeds.

22
  • CHRYSTIANE DO NASCIMENTO BRITO DE OLIVEIRA
  • PERFORMANCE EVALUATION OF BORON DOPED DIAMOND ELECTRODE IN THE ELECTROCHEMICAL DEGRADATION OF DIFFERENT TEXTILE DYES: EFFECT OF ELECTROCATALITIC MATERIAL AND REACTORS

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • DJALMA RIBEIRO DA SILVA
  • DOUGLAS DO NASCIMENTO SILVA
  • MARCO ANTONIO QUIROZ ALFARO
  • Data: Nov 8, 2019


  • Show Abstract
  • The efficiency of the advanced electrochemical oxidative process (POAE's) in the treatment of synthetic textile effluent was the object of this study, through the electrochemical performance of the boron-doped diamond (BDD) electrode, Ru0.3Ti0.7O2 and Pt, investigating the electrochemical oxidation of the dyes Acid Violet 7 (AV7) and Disperse Yellow 3 (DY3). Different experimental variables were applied, such as electric current density (15, 30, 40 and 60 mA cm-2), pH, support electrolytes (Na2SO4 and NaCl) and different electrochemical reactors with different input-output cylindrical reaction cells (I-O), one in parallel and one perpendicular to the electrodes. To achieve the objectives proposed in this study, color removal, COD, UV-Visible, COT and HPLC analyzes were performed. With the obtained results, it was investigated the degradation capacity of the textile dyes comparing the electrodes. It was verified that the BDD electrode presented better efficiency, in relation to the other electrodes, for the treatment of the textile effluents. Comparing the electrochemical reactors (parallel and perpendicular), the mass transfer coefficients (Km), 1.86 × 10−5 m s −1 and 2.56 × 10−5m s –1, respectively, were calculated using the technique acurrent limitation. The degradation results indicated that the most efficient COD removal cell was always achieved in the I-O flow cell in parallel at all current densities. This can be attributed to the possibility of some stagnation in the lateral regions of the electrodes, which favor a longer contact time between the pollutant and the anode. 

23
  • HELOIZA FERNANDA OLIVEIRA DA SILVA ATHAYDE
  • GOLD AND SILVER NANOPARTICLES APPLIED TO BIOLOGICAL SYSTEMS

  • Advisor : LUIZ HENRIQUE DA SILVA GASPAROTTO
  • COMMITTEE MEMBERS :
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • MAURICIO ROBERTO BOMIO DELMONTE
  • ARNOBIO ANTONIO DA SILVA JUNIOR
  • PIERRE BASILIO ALMEIDA FECHINE
  • SHERLAN GUIMARÃES LEMOS
  • Data: Nov 29, 2019


  • Show Abstract
  • Neoplasia and bacterial resistance are among the main challenges in the biomedical área. It requires study and development of alternative. Metal nanoparticles have shown promise in such applications. This thesis presents applications of gold and silver nanoparticles (NanoAu and NanoAg, respectively) to biological systems. NanoAu are considered as potential drug delivery platforms. However, understanding the interaction of these particles with living organisms before their use as nanocarriers is essential. Thus, the first study presents the synthesis and characterization of NanoAu and the investigation of anti-inflammatory, analgesic and antitumor effects, as well as their biodistribution and their effect on various tissue types. The NanoAu were synthesized by enviromental friendly route and characterized by transmission electron microscopy (TEM) and UV-Vis spectroscopy (UV-vis). Subsequently, HT-29 cells were exposed to NanoAu and apoptosis was evaluated by caspase-3 activity. Regarding in vivo assays, NanoAu were administered to female Swiss mice and male rats for further evaluation of their anti-inflammatory and analgesic properties. NanoAu biodistribution and its impact on tissues were studied by UV-Vis spectroscopy and histopathological analysis, respectively. Cell apoptosis was dose dependent for NanoAu concentrations between 40 µg ml -1 and 80 µg ml -1 (p <0.05). The best anti-inflammatory activity was observed at 1500 mg kg-1, which led to a reduction of 49.3% in leukocyte migration. NanoAu showed peripheral analgesia at 1500 mg kg-1 and were found in the liver, spleen, kidney and lung of Swiss mice. Histopathological examination revealed extravasation of red blood cells in the lung. The second study addresses the investigation of the metabolic synergistic effect of NanoAg combined with doxycycline hiclate, DO. ATR-FTIR biospectroscopy of bacterial samples of Staphylococcus aureus was used. PCA was applied to the spectrum group showing a pattern of differentiation between the classes. Due to the complexity of the obtained data (presenting overlapping bands and enough variance within the same class), it was necessary to use the PLS-DA variable selection tool. It was identified that all antimicrobials in this study interfere with protein synthesis. Sensitivity values of 75%, 100% and 75% for Control, NanoAg and DO respectively. It was also determined whether or not there was a statistical difference in the mean absorbance values, which allowed us to indicate in which cases the biomarkers were more expressed, which suggested the possible cause of the synergy of the antibacterial effect of NanoAu combined with doxycycline hyclate. The results obtained in both studies confirm the potential of synthesized nanoparticles in our research group as possible nanocarriers.

24
  • MAIARA BARBOSA FERREIRA
  • TREATMENT OF HAZARDOUS EFFLUENTS BY USING ELECTROCHEMICAL TECHNOLOGIES COMBINED WITH OTHER ADVANCED OXIDATION PROCESSES

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • ALINE MARIA SALES SOLANO
  • CARLOS ALBERTO MARTINEZ HUITLE
  • DANYELLE MEDEIROS DE ARAUJO
  • DJALMA RIBEIRO DA SILVA
  • MARCO ANTONIO QUIROZ ALFARO
  • Data: Nov 30, 2019


  • Show Abstract
  • The treatment of hazardous polluted liquid waste is a topic of great interest worldwide, as environmental pollution issues are promulgated annually, especially in hazardous waste, air pollution and wastewater. Wastewater can be result from overuse of pesticides and fertilizers on farmland, infiltration of livestock dams, accidental discharge of harmful pollutants, industrial wastewater, landfill leachate, oil spill and oil rigging, improper waste disposal and stocks, among others. Faced with this problem, many studies have appeared that aim to reduce or eliminate the damage caused by these contaminants. One of the alternatives more widely used in recent years is the combination of existing technologies in order to enhance the efficiency in the decontamination processes or to propose a pre-treatment prior to the use of conventional alternatives, including the biological treatments. In this work, we initially propose the study of the use of a electrochemical technology coupled with soil and wastewater remediation. The use of anodic oxidation combined with advanced oxidative processes has also been investigated using nine AOP-ZVI combinations to determine the best combination to be used as a pre-treatment for biological degradation processes of organochlorine pollutants. This was achived assesing the changes in short-term respiratory behavior, toxicity and biodegradability. Clopyralid has been used as a chlorinated hydrocarbon model. Three AOPs were studied: AO-MMO, AO-BDD and photolysis in three different modes: no ZVI addition, ZVI dehalogenation as pretreatment and ZVI dehalogenation concurrent with AOP treatment. The results showed that technologies can successfully treat Clopyralid-polluted residues and the observed effects are significantly improved by de-halogenating the residues with ZVI prior to treatment or simultaneously with AOP treatment.

25
  • ANDERSON DIAS VIANA
  • SILVER NANOPARTICLES STABILIZED BY RICINOLEIC ACID AND ITS EPOXIDED FORM APPLIED AS A CYSTEINE SENSOR AND ANTIMICROBIAL AGENT

  • Advisor : LUIZ HENRIQUE DA SILVA GASPAROTTO
  • COMMITTEE MEMBERS :
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • JOSE LUIS CARDOZO FONSECA
  • RAFAEL DA SILVA FERNANDES
  • JOSÉ ROBERTO SIQUEIRA JUNIOR
  • SEVERINO ALVES JUNIOR
  • Data: Dec 2, 2019


  • Show Abstract
  • Nanoparticles have been applied for their large surface area, their reactivity and the new properties that do not exist in the bulk phase. New syntheses using natural products have been used to make the process more ecofriendly. However, the use of raw natural product requires high temperatures or a long synthesis time. In this work we use ricinoleic acid extracted from castor oil, due to its biodegradability, higher water solubility and availability, as it is a characteristic plant of Brazilian northeastern. Ricinoleic acid epoxidation was done to increase the reducing capacity. In this work, the synthesis of silver nanoparticles with ricinoleic acid surfactant (AgSAR) and its epoxidized form (AgSEAR) was optimized to be applied as cysteine sensors and antibacterial agents. Maximum UV-Vis absorbances of 420 nm for AgSAR and 405 nm for AgSEAR were obtained, indicating nanoparticle formation. The optimal design of the experiment was the concentration of 0.5 mmol∙L-1 Ag+ and 20 mmol∙L-1 of surfactant in AgSAR synthesis and 0.3 mmol∙L-1 of Ag+ and 20 mmol∙L-1 of the surfactant in AgSEAR synthesis. Synthesis time decreased from 10 days  with AgSAR to 6 hours with AgSEAR. The average nanoparticle size was 16.70 nm for AgSAR and 17.80 nm for AgSEAR, while for EDL 75.42 nm for AgSAR and 82.10 nm for AgSEAR size diameter were obtained. This size difference indicates that surfactants are found as micelles around the nanoparticle. The nanoparticles were elective to cysteine with a detection limit of 3.49 μmol∙L-1 for AgSAR and 16.67 μmol∙L-1 for AgSEAR. In the antibacterial application, there was total inhibition of growth at a concentration of 18 mg/L for AgSAR and 11 mg/L for AgSEAR.

26
  • DENNYS SALVINO SERGIO PEREIRA
  • SYSTEMS DEVELOPMENT BASED TO CALCIUM SULPHATE TO APPLICATION IN OIL WELLS CEMENTING

  • Advisor : JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • COMMITTEE MEMBERS :
  • BRUNO LEONARDO DE SENA COSTA
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • MARCOS ALLYSON FELIPE RODRIGUES
  • MIGUEL ANGELO FONSECA DE SOUZA
  • RODRIGO CESAR SANTIAGO
  • Data: Dec 12, 2019


  • Show Abstract
  • The Portland Cement (PC) production is directly linked to different environmental impacts. Those impacts are associated with different extraction phases going from the raw material stage to the clinquerization stage, having the emission of large volumes of CO2 and very high energy utilized. The search to alternative cement materials may have similar technological properties and with less aggression to the environment, has become the target of several segments to Portland Cement industry. Calcium sulfate hemi-hydrate (HH) is a binder with reduced environmental impacts linked to both its production and use, presented as a less aggressive material to the environment. Calcium sulfate systems can be used both in their pure form and can have their properties improved upon partial replacement by Portland cement and other materials can also be used as an agent of pozzolanic activity, as a Rice Husk Ash (RHA). This paper is aimed to develop and analyze systems based on pure calcium sulfate and with the addition of Portland Cement and Rice Husk Ash (RHA), as an alternative to the formulations used in the initial stages of cementation of wells of Petroleum. For the development of this study, slurrys with water/gypsum factors (FAGs) between 0.5-0.6 were prepared, being submitted to different cures ages (24 hours, 7 and 28 days) and temperatures (27, 38 and 60 ºC). The slurrys were aditived using a handle retarder (sodium tetraborate) and superplasticizer (polycarboxylate), in order to obtain the technological properties required for application in the petroleum industry. These formulations were evaluated through tests of compressive strength, rheological parameters and permeability, besides the use of thermal characterization techniques (TG / DTG), X-ray diffraction (XRD), scanning electron microscopy (SEM-EDS) HH and its formulations with CCA and CPP. The results showed that the system based on pure calcium sulfate type HH-α and HH-β with 30% substitution for CCA and cement, present satisfactory results of compressive strength, approximately 13% higher than the formulation with CPP, traditionally used in cementing operations, with higher values, compared to the PC formulation traditionally used in cementing operations. The systems presented technological properties applicable in well cementation operations with depths ranging from 500-1000m, considering a geothermal gradient of 1.7 F / 100ft. In addition, the cost of HH is on average 60-70% cheaper than the current CPP.

27
  • GIZELY DE VASCONCELOS LEITE CAVALCANTE
  • CHEMICAL AND BIOLOGICAL PROSPECTION OF MARINE BACTERIA COLLECTED IN THE BRAZILIAN COAST

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • JACQUELINE DO CARMO BARRETO
  • LIVIA NUNES CAVALCANTI
  • LUCIENE DA SILVA SANTOS
  • RENATA MENDONÇA ARAUJO
  • SAVIO MOITA PINHEIRO
  • Data: Dec 17, 2019


  • Show Abstract
  • The importance of natural products in the discovery of new drugs has been widely documented, including their contribution to the development of current medications. Marine organisms, in turn, may be considered the most recent source of bioactive natural products in relation to terrestrial plants and non-marine micro-organisms. For some time, modern medicine relies on natural microbial products to treat infectious diseases, cancer and other persistent diseases. Included among current efforts to discover new drugs originating from natural products are studies of new populations of bacteria, including those residing in the marine environment. Collectively, these bacteria are producing a wealth of new structures, including agents that are advancing through various stages of clinical development, solidifying the importance of exploring new habitats and resources in the search for new secondary bacterial metabolites. This paper reports the chemical and biological study carried out with gram-positive and gram-negative marine bacteria collected in Rio Grande do Norte, Ceará and the coast of São Paulo, focusing on the isolation of secondary metabolites present in a gram-positive bacterium of the genus identified such as Streptomyces. Several large-scale cultures of the microorganisms with the highest cytotoxic activity were obtained in order to obtain a sufficient quantity to obtain crude extracts that were analyzed by chromatographic techniques such as High Efficiency Liquid Chromatography, Adsorption Chromatography and Molecular Exclusion Chromatography. The chromatographic fractionation of the ethyl acetate extract of the bacterium BRB-081 resulted in the isolation of eighteen substances, among which two acids, called Phenylacetic Acid and Vanillic Acid, the latter being reported for the first time in the genus, a tyramine called N -methylthyramine with antifungal and antitumor activity reported and two unpublished compounds in the literature. The other isolated compounds are still in the elucidation phase. The structural determination of the isolated secondary metabolites was performed using the techniques: 1H and 13C Nuclear Magnetic Resonance through uni and bidimensional pulse sequences, mass spectrometry and comparison with literature data. In addition to the isolated substances, 45 substances of the hexane phase were identified by CG-MS. LC-MS analyzes provided the exact mass and fragmentation profile compatible with the structure of Surugamide A and two other analogs, one of which is unknown in chloroform fractions, this chemical class has only recently been described, offers much to investigate. The isolated substances, phases, fractions and crude extracts obtained were submitted to cytotoxic assays using human colon cancer cells (HCT-116). In these tests, it was observed that the BRB081 extract was the most active among the extracts produced and that the analysis of the phases in hexane and chloroform also showed activity considered satisfactory, being the chloroform phase the most active. Fractions containing surugamides were also tested and showed promising results. However, the isolated substances did not present satisfactory cytotoxicity, demonstrating the synergism between the molecules.

28
  • ROMÁRIO CEZAR PEREIRA DA COSTA
  • MINERAL-SUPPORTED SOLID Cu AND Mn-BASED OXYGEN CARRIERS FOR USE IN CHEMICAL LOOPING COMBUSTION TECHNOLOGY WITH CO2-CAPTURE

  • Advisor : DULCE MARIA DE ARAUJO MELO
  • COMMITTEE MEMBERS :
  • DULCE MARIA DE ARAUJO MELO
  • LUCIENE DA SILVA SANTOS
  • RENATA MARTINS BRAGA
  • RODRIGO CESAR SANTIAGO
  • TIAGO ROBERTO DA COSTA
  • Data: Dec 20, 2019


  • Show Abstract
  • Energy systems with carbon dioxide capture and storage have been shown to be an alternative to minimize greenhouse gas emissions. The capture of CO2 by combustion by chemical recirculation, from Chemical Looping Combustion (CLC), stands out for not having energy penalty, but the cost and efficiency of the process depend on the materials used as oxygen carriers. In view of this, this work aims to synthesize and evaluate solid copper and manganese oxygen carriers supported on diatomite and kaolin in order to produce energy through indirect burning of fossil fuels through the CLC process. The carriers were synthesized by the incipient wet impregnation technique and characterized by X-ray diffraction, scanning electron microscopy equipped with an X-ray dispersive energy analyzer, mechanical resistance, air jet index, reduction at programmed temperature and reactivity tests by thermogravimetry. It was also verified, by temogravimetry, the oxygen transport capacity of each sample (Roc). X-ray diffraction analysis detected the presence of characteristic peaks of the active phases (CuO, Mn3O4 and Mn7SiO12), which were also confirmed by programmed temperature reduction tests. The mechanical resistance of conveyor particles below 1N is unviable in CLC beds. ¾ of the materials studied in this work obtained mechanical strength higher than 2N. The reactivity of the samples was evaluated by thermogravimetry, where three reduction and oxidation cycles were performed. In this analysis it was observed that CuO supported in diatomite (Cu-D) stood out in relation to the others, due to its high reactivity and oxygen transport capacity. This material obtained a conversion percentage of H2 above 95%, followed by kaolin supported CuO (~ 90%). Manganese-based materials showed good H2 and CH4 conversion results (above 90%), but were not efficient in oxidation, losing reactivity at each cycle. The copper-based samples are promising, as they obtained mechanical resistance above 2N, high oxygen transport capacity and fuel conversion efficiency, with values above 95%.

2018
Dissertations
1
  • IRIELSON CARNEIRO DE LIMA
  • STUDY OF THE MAGNETIC PROPERTIES OF THE MIXED OXIDE OF IRON AND MANGANESE III

  • Advisor : ADEMIR OLIVEIRA DA SILVA
  • COMMITTEE MEMBERS :
  • ADEMIR OLIVEIRA DA SILVA
  • JARLEY FAGNER SILVA DO NASCIMENTO
  • MARIA DE FATIMA VITORIA DE MOURA
  • Data: Jan 12, 2018


  • Show Abstract
  • The continued and growing demand for high-performance, more versatile and miniaturized electronic devices has increased interest in the study and development of new materials. The multiferroic (magnetoelectrics, magnetoelastoelectrics, and ferroelectric-ferroelectric) has emerged as of great interest to associate two or more ferroic properties in the same material. In this work the mixed perovskite of iron and manganese (MnFeO3) was synthesized by the combustion method, sintered at different temperatures (500 ° C, 750 ° and 900 ° C) and characterized by X-ray diffraction associated with the Rietveld method (DRX-Rietveld ) and X-Ray Fluorescence (FRX), while its magnetic properties were studied by Vibrating Sample Magnometry (VSM) and Electronic Paramagnetic Resonance (EPR).

    Analysis of the DRX-Rietiveld spectra showed that in the sample sinteerized at 500 ° formation of oxides was formed while only 64% of the material was transformed into FeMnO3 of cubic structure, whereas in the samples sintered at 750 and 900 ° the formation almost that absolute of  FeMnO3 with a small excess of iron oxide III, attributed to an experimental error. The X-ray fluorescence confirms the XRD information, showing the percentages of oxides formed.

    Paramagnetism was investigated by EPR analysis and showed a wide signal in the region of 0.3 tesla, the calculation of the factor g gave 2.043 which is close to the theoretical value for a free electron confirming the paramagnetism. The magnetization curve as a function of the applied field (M x H) obtained by the Vsm technique, shows values for superparamagnetic material.

2
  • TALES GOMES DA SILVA
  • SYNTHESIS AND CHARACTERIZATION OF CALCIUM ZIRCONATE (CaZrO3)

  • Advisor : ADEMIR OLIVEIRA DA SILVA
  • COMMITTEE MEMBERS :
  • ADEMIR OLIVEIRA DA SILVA
  • JARLEY FAGNER SILVA DO NASCIMENTO
  • MARIA DE FATIMA VITORIA DE MOURA
  • Data: Jan 15, 2018


  • Show Abstract
  • Perovskite compounds, such as Calcium Zirconate, have the structural formula ABO3 and form a class of materials with interesting optical, magnetic and electrical properties, which has several scientific and technological applications. Perovskite materials will be portrayed in this work, because they present physicochemical stability and interesting specific properties. Therefore, this work aims to analyze the synthesis of perovskites by the combustion method, performing the characterization of the samples by means of X-ray diffraction (XRD), Rietveld refinement, Scanning Electron Microscopy (SEM), Dispersive Energy Spectroscopy EDX or EDS) and X-ray Fluorescence. The evolution of the CaZrO3 crystallization process and the composition of the samples were accompanied by X-ray diffraction. The obtained X-ray patterns were refined with the Rietveld method. Scanning electron microscopes were used to identify the presence of defects and morphology of the samples. The characterization methods showed structural differences in the samples in function of the variation of the composition of the system. The results indicate a transition from deep defects to shallow defects due to the presence of secondary phases in the system.

3
  • BRUNO HENRIQUE DE ALBUQUERQUE PEREIRA
  • DEVELOPMENT AND STUDY OF THE PROPERTIES IN AQUEOUS MEDIUM OF THERMO-RESPONSIVE CARBOXYMETHYLCELLULOSE DERIVATIVES
  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • MORSYLEIDE DE FREITAS ROSA
  • RENATA MENDONÇA ARAUJO
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Jan 25, 2018


  • Show Abstract
  • The present work studies the synthesis and characterization of two copolymers with thermoresponsive properties, consisting of amino terminated poly (ethylene oxide / propylene oxide) grafts in a carboxymethylcellulose (CMC) backbone. Grafting occurred from a coupling reaction between the –NH2 group of the Jeffamine® M-1000 and M-2070 (commercial nomenclature of polyetheramines) with the COO- groups from CMC, by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. The structural characterization of the copolymers and their precursors was done by means of IR and 1H NMR spectroscopy. On the IV spectrum of the copolymers it was possible to observe the effectiveness of the grafting reaction and the determination of the degree of grafting in both copolymers. The behavior in aqueous medium was studied thru of visual tests, rheological analysis, UV-vis spectroscopy and dynamic light scattering, and the thermo-associative properties of the synthesized copolymers were verified in saline medium. The CMC-g-Jeffamine® M-1000 copolymer exhibited high apparent viscosity values even in a hostile medium, with high ionic strenght and high temperature conditions. The CMC-g-Jeffamine® M-2070 copolymer exhibited the thermothickening behavior, however its viscosity values are low when compared to the CMC-g-Jeffamine® M-1000 copolymer.

4
  • DAYANA PATRÍCIA DA SILVA PENHA MACEDO
  • SYNTHESIS, CHARACTERIZATION, REACTIVITY AND ANTIBACTERIAL EVALUATION OF RUTHENIUM NITROSYL COMPLEXES

  • Advisor : FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • COMMITTEE MEMBERS :
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • MARCIA RODRIGUES PEREIRA
  • DANIEL DE LIMA PONTES
  • LUIZ GONZAGA DE FRANÇA LOPES
  • Data: Jan 30, 2018


  • Show Abstract
  • The biological significance of nitric oxide in cardiovascular control, in neurotransmission and in defense mechanisms against microbes and tumor cells has strong interest in the coordination chemistry to develop complex capable of releasing NO in the organism. In this context, ruthenium nitrosyl complexes present a biological potential in releasing the NO molecule in a selective and controlled manner, because they are thermodynamically stable and photochemically active compounds. Thus, the synthesis, characterization, reactivity and antibacterial test of complex of the type cis-[Ru(bpy)(phen)L(NO)](PF6)n, where L are the imidazole and sulfite ligands, bpy = 2,2’- bipyridine and phen = 1,10'-phenanthroline. Complex nitrosyls were obtained by dissolving the nitro complexes in methanol and adding trifluoroacetic acid with stirring. Through electronic spectroscopy in aqueous media, it was possible to identify as intraligant bands of bipyridine and phenanthroline ligands as well as metal charge transfer bands for both the polypyridine ligands in the region of 330 nm and for the nitrosyl ligand around 476 nm. The vibrational spectra in KBr pellets showed NO+ stretching at high frequencies in the 1900 cm-1 region indicating that nitric oxide is found coordinated to the metal center. When analyzing the cyclic voltammograms, in NaTFA 0,1 mol L-1, of the nitrosyl complex, a single almost reversible process with respect to the NO+/0 redox pair was observed. Regarding the reactivity was done the acid-base equilibrium, noting that pH 6.3 and 8.9 occurs the conversion of nitrosyl to nitrite to the complexes with imidazole and sulfite, respectively. In order to verify the release of nitric oxide by square-wave voltammetry, kinetics with biological reductant and photochemical study with white light, it was inferred that the release of NO occurs by a chemical reaction in which the ligand is reduced in the NO+ to NO0, this is released due to the weakening of the link RuII - NO0 and in its position coordinates itself to the molecule of water, forming the aqua complex. The antibacterial activity of the nitrosyl complexes was tested on the bacterium Pseudomonas aeruginosa ATCC 9027 using the broth microdilution method. Thus, observed through MIC, the complexes are able to inhibit bacterial growth in minimum concentrations of 57.23 mM for the complex with imidazole and 200.8 mM with sulfite.

5
  • RAFAEL CHAVES LIMA
  • ZEOLITE MORDENITE: STUDY ABOUT ITS FORMATION AND CRYSTAL SIZE

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • ANTONIO SOUZA DE ARAUJO
  • ADONAY RODRIGUES LOIOLA
  • Data: Jan 30, 2018


  • Show Abstract
  • A system for the synthesis of the mordenite zeolite was studied, which made it possible to obtain the MOR phase without indicating the presence of any other phase. Variations in the synthesis parameters were performed aiming the establishment of the relationship between the size and the morphology of the synthesis products with the modifications made. The crystallization temperature showed to be an essential factor in the size of particles and crystallites. Dilution of the synthesis gel provided reduced crystallite aggregation and the variation of the water content in the synthesis implied changes in the zeolitization rates. The sodium content modified the growth of the crystals and the increase of intergrowths and aggregations of particles. Aging did not imply any variation in zeolite formation. The change in the silica source increased the growth rate of the crystals and contributed to changes in the size of the crystals. Larger crystals were obtained from systems with higher concentrations of sodium cations as nanocrystallite aggregates and some nanoparticles were synthesized with the lowering of temperature and the use of silica source with greater specific area. Aggregates of small pure mordenite crystallites of up to about 50 nm were obtained with syntheses performed at 150 ° C, with a lower content of Na + and water ions in the gel, dilution of the already prepared gel and with the use of silica sources of greater specific area (relative to this type of material). Opposite conditions enabled the highest growth, generating crystals up to 1 μm on average. The results showed that it is possible to exert some control over the particle size and crystallites of the mordenite zeolite by adjusting parameters inherent to the conventional synthesis system.

6
  • MARFRAN CLAUDINO DOMINGOS DOS SANTOS
  • DETECTION AND TYPING OF ARBOVIRUS (DENGUE, ZIKA AND CHIKUNGUNYA) BY INFRARED IN CONJUNCTION WITH MULTIVARIATE ANALYSIS TECHNIQUES

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • KASSIO MICHELL GOMES DE LIMA
  • FABRICIO GAVA MENEZES
  • JOSELIO MARIA GALVAO DE ARAUJO
  • HECTOR CASIMIRO GOICOECHEA
  • Data: Jan 30, 2018


  • Show Abstract
  • The objective of the studies reported in this dissertation is to evaluate the use of infrared spectroscopy in conjunction with chemometric techniques of multivariate analysis, as a new tool for detection and typing of arboviruses present in clinical samples. In this dissertation there are 4 articles: 1 review article and 3 research articles. The review article is a survey of the main techniques spectroscopic and multivariate analysis techniques used in studies in the field of virology in the last 10 years, as well as the advantages of these techniques against standard techniques. In the first research article, multivariate models based on discriminant analysis were constructed with the objective of quantitatively discriminating the DENV-3 serotype present in four different concentrations in serum and blood samples. In the second study, variable selection techniques were applied with the objective of discriminating infected serum and blood samples in the laboratory, and also to predict which serotype is responsible for the infection. In the third study, the ability of the technique to discriminate between 4 groups of samples: dengue (blood samples from patients diagnosed with dengue), Chikungunya (blood samples from patients diagnosed with Chikungunya), Zika (blood samples from patients diagnosed with Zika) and healthy (blood samples from healthy volunteers). The multivariate analysis algorithms used were Principal Component Analysis-Linear Discriminant Analysis (PCA-LDA), Successive Projections Algorithm-Linear Discriminant Analysis (SPA-LDA) and Genetic Algorithm-Linear Discriminant Analysis (GA-LDA). The performance of the technique was evaluated through calculations of sensitivity, specificity, positive and negative predictive values, Youden index and positive and negative likelihood ratio. The results were encouraging, and showed that the spectroscopy used in conjunction with multivariate analysis techniques has the potential to detect and identify the variations caused by the presence of dengue virus in biological samples, and to provide a fast result in comparison to the diagnostic techniques used in clinical routines.

7
  • JOE VÍTOR ALVES DO NASCIMENTO
  • EVALUATION OF THE PROPERTIES OF NATURAL AND SYNTHETIC MONTMORILLONITE CLAYS PILLARED WITH POLIHYDROXY CATIONS OF ALUMINUM

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • FABIO GARCIA PENHA
  • LUIZ CARLOS BERTOLINO
  • SIBELE BERENICE CASTELLA PERGHER
  • Data: Jan 31, 2018


  • Show Abstract
  • The montmorillonite claymineral was synthesized under hydrothermal conditions, autogenic pressure, acidic and hydrofluoric medium. Both synthetic and natural clays were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), infrared spectroscopy (FTIR), adsorption and desorption of N2, scanning electron microscopy (SEM) and energy dispersive (EDS). The synthetic clay presented an X-ray diffraction pattern with characteristic reflections of montmorillonite, like natural clay, with the exception of the presence of quartz in the mineralogical composition of the latter. By means of the analyzes, a greater amount of aluminum was identified for the synthetic clay, as well as a more meso-macroporosity character and compositional purity, when compared with the natural clay. The pillarization of the clays was done starting from two distinct sources of Keggin ions, one commercial and the other produced in the laboratory. The resulting materials were characterized by XRD, TG, FTIR and adsorption and desorption of N2. The synthetic pillared materials presented a disorganized, but pillared structure, as verified by means of X-ray diffraction and textural analysis. The natural clay also pillared with both sources presented characteristics typical of the pillared materials. The use of aluminum chlorohydrol (ACH) as a source of Keggin ions generated materials with higher amounts of aluminum species in the interlamellar space, resulting in materials with a lower volume of micropores. The specific areas of the natural pillared materials were higher than those calculated for synthetic pillared clays due to a greater contribution of the microporosity created with the pillarization process

8
  • AMANDA SAYURE KASUYA DE OLIVEIRA
  • SYNTHESIS AND CHARACTERIZATION OF ALUMINUM OXIDE AND/OR SILICON BY THE PROTEIN SOL-GEL METHOD

  • Advisor : TIAGO PINHEIRO BRAGA
  • COMMITTEE MEMBERS :
  • TIAGO PINHEIRO BRAGA
  • AMANDA DUARTE GONDIM
  • SIBELE BERENICE CASTELLA PERGHER
  • JOSÉ MARCOS SASAKI
  • Data: Feb 2, 2018


  • Show Abstract
  • In order to synthesize nanostructured substrates from a simple, renewable, efficient, low cost and high catalytic performance methodology, substrates based on aluminum oxide and / or silicon oxide were synthesized using the protein sol-gel method using porcine gelatin as an organic precursor and aluminum nitrate and / or tetraethyl orthosilicate (TEOS) as inorganic precursors. The characterization was performed by thermogravimetric analysis (TG), X-ray fluorescence (XRF), X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2 sorption, porosimetry of Mercury and catalytic tests (ethanol model dehydration reaction). The XRD diffractograms showed an amorphous material profile characteristic of highly dispersed metallic oxides. The TG results indicated the total release of the organic and inorganic material at the calcination temperature used, occurring at different mass loss intervals. This information was reaffirmed by the FTIR spectra, which showed the presence of a hybrid material and gelatin structure bands before the calcination and disappeared in the solid spectrum after calcination, indicating the loss of organic matter after the heat treatment. The spectra exhibited M-O stretching vibration at low wavelengths following calcination that are related to metal oxides (SiO 2 and Al 2 O 3). The images acquired by SEM suggested obtaining a highly porous material with very different characteristics depending on the composition of the support. The sorption isotherms of N2 indicated the presence of a micro-mesoporous oxide with interesting texture properties, especially for the supports containing aluminum oxide and silicon oxide. The results of ethanol dehydration showed higher selectivity to diethyl ether compared to ethylene while acetaldehyde showed no results. From the reaction data, the following order of acid resistance was obtained: 2 Si: Al> Si: 2Al> Si: Al> Al, proving that the Si: Al ratio and surface area influence this sequence.

9
  • ANTONIO VICENTE DE MENDONÇA JUNIOR
  • THERMAL AND THERMOCATALITIC CONVERSION OF THE BIOMASS USING MESOPOROUS MATERIALS FOR THE OBTAINMENT OF HYDROCARBONS

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • VALTER JOSE FERNANDES JUNIOR
  • ANNE GABRIELLA DIAS SANTOS
  • NATALY ALBUQUERQUE DOS SANTOS
  • Data: Feb 5, 2018


  • Show Abstract
  • A demand for fossil fuels is high worldwide, generating large environmental impacts in its extraction and burning. Another factor that becomes notorious and discarded of household waste is no environment adding ecological damage. From two pillars, it is necessary to use renewable resources with regard to biomass of residual vegetable oils. Therefore, this work offers purposes to obtain renewable fuels through pyrolysis in the presence of mesoporous catalysts. As biomass listed for the oil work of aquatic Pachira, commonly called munguba, and frying oil, its reuse is necessary for reuse in fuel sources. As a catalyst, it was used as mesoporous molecular sieves, KIT-6 and MoKIT-6. The catalysts were characterization by X-Ray Diffraction, Thermal Analysis (TG / DTG), Electron Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Dispersion Spectroscopy (EDX). Over time, the structuring of the crystals of the standard KIT-6 and MoKIT-6, this one presents an oxide phase of Molybdenum (TG / DTG), a physical structure of the KIT-6 crystals. (MoO3) at the catalyst surface and percent proposed was successfully ratified in the EDX descriptions. In the kinetic study, it was evidenced that in the frying oil there was an evident action of MoKIT-6, obtaining practically linear during the conversion, obtaining inferior energies of activation. To obtain the renewable hydrocarbons, the biomasses were submitted to thermal and thermo-catalytic pyrolysis and the product obtained was analyzed by: GC-MS, viscosity, specific mass, acid number. In summary, it can be concluded that all the specific characterization of KIT-6 and its functionalized form MoKIT-6 were obtained within the planned, and the frying oil could be successfully converted and bio- oil with excellent characteristics for use as fuels.

10
  • FRANCIMAR LOPES DE SOUSA JUNIOR
  • DEVELOPMENT NEW COPPER COMPLEXES WITH PHENANTHROLINE DERIVATIVES AND ISONIAZID

  • Advisor : ANA CRISTINA FACUNDO DE BRITO PONTES
  • COMMITTEE MEMBERS :
  • ANA CRISTINA FACUNDO DE BRITO PONTES
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • SÉRGIO DE PAULA MACHADO
  • Data: Feb 5, 2018


  • Show Abstract
  • The imidazole derivatives of 1-10-phenanthroline-5,6-dione (phend) have biological properties, such as DNA cleavage, antitumor and antibacterial, in addition, synthetic versatility allows the inclusion of groups that enhance their characteristics biochemical. In this context, the present work aims to synthesize and characterize new copper complexes with phenanthroline derivatives having as additional ligand chlorides and isoniazid (INH). The complexes [Cu(L)Cl2] and [Cu(L)(INH)2]Cl2 were synthesized, where L is phend and the imidazole derivatives obtained from the reaction of phend with 4-cyanobenzaldehyde and 4-nitrobenzaldehyde, named of L-CN and L-NO2 respectively. The ligands and complexes were synthesized from methodologies adapted as base similar compounds described in the literature and characterized by spectroscopic (Uv-Vis, IV and Raman), thermal and electrochemical techniques. From the vibrational spectra were observed the vibrational modes indicative of the phenanthroline system of the L ligands in 810 and 740 cm-1. The Compounds with the phend ligand show C = O stretching around 1690 cm-1 and the complexes with L-CN and L-NO2 exhibited the characteristic stretches of imidazole of these ligands. Infrared of the INH-containing complexes, it was determined that this ligand was coordinated in the bidentate form, due to the displacements of the amide modes I and II compared to the free ligand. The electronic spectra of the compounds in DMSO showed intraligant bands in the region of 260 to 400 nm, for the complexes the transitions d-d in 767, 741 and 732 nm were also observed for [Cu(phend)Cl2] (CuPhenD), [Cu(L-CN)Cl2] (CuLCN) and [Cu(L-NO2)Cl2] (CuLNO2) respectively. Complexes with INH, they presented the d-d bands at 760, 721 and 719 nm for [Cu(phend)(INH)2] Cl2 (CuPNI), [Cu(L-CN)(INH)2]Cl2 (CuCNI)and [Cu(L-NO2)(INH)2]Cl2 (CuNO2I) respectively. Additionally, thermal decomposition and thermal stability of the compounds were observed by the thermal analyzes (TG, DTG and EGA). The cyclic voltammograms of the [Cu(L)Cl2] complexes presented only one redox pair indicative of the Cu2+/Cu+ process, with E1/2 of 262 (CuPhenD), 195 (CuLCN) and 150 mV (CuLNO2). However, of the chlorides by INH it was possible to verify two redox pairs referring to Cu2+/Cu+ and Cu+/Cu0 processes.

11
  • DJALAN FRANÇA DE LIMA
  • Preparative and computational study of the reaction of 2,3-dichloroquinoxaline and cysteine methyl ester

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • LIVIA NUNES CAVALCANTI
  • NORBERTO DE KASSIO VIEIRA MONTEIRO
  • Data: Feb 8, 2018


  • Show Abstract
  • Traditionally, organic chemistry text books suggest araomatic/heteroaromatic nucleophilic substitution (SNAr) procedding via Meiseinheimer-type intermediate mechanism. Quinoxaline are a class of nitrogen heterocycles with application in many fields. IN this context, several synthetic methodologies based on SNAr reactions involving the substrate 2,3-dichloroquinoline (DCQX) have been reported in literature. In fact, DCQX is adequately for this type of reaction since it has two chlorine atoms as potential leaving group due the activation promoted by electron-deficient nature of the quinoxaline ring. The present work presents a combined experimental and theoretical study involving the reaction of DCQX and cysteine methyl ester (CysMe). The choice for CysMe arrives from its interesting nucleophilic nature and due the reaction products being potentially applied in many areas. On the other hand, a computational study of the mechanisms of this reaction is especially interesting due the small number of reports concerned on SNAr involving heterocycles substrates. The reaction of DCQX and CysMe in DMF, in the presence of potassium carbonate, afforded a major product (yielding 57%) in which spectroscopic characterization (NMR and IR) suggest to be 3,4-dihydro-2H-1-thia-4,9,10-triaza-anthracene carboxylic acid methyl ester (CysQX5). A secondary product is also formed in the reaction, and this has not been properly isolated and characterized.  Theoretical calculations (M06-2X/6-311+g(3df,2p) and B3LYP 6-31+g(d,p)) were performed in attempt to screen all possibilities associated to the reactivity of CysMe toward DCQX. To the moment, this work is based on the thermodynamics aspects. They were evaluated the Gibbs free energy variation between the reagents and all possible products, including those originated from monossubstituion by sulfur atom (CysQX1) or nitrogen atom (CysQX2), as well as dissubstitution by sulfur atoms (CysQX4), by nitrogen atoms (CysQX4), or simultaneously by sulfur and nitrogen (CysQX6), besides the cyclized product CysQX5. Both neutral and anionic nucleophiles were taken into account in the reactions originated from nucleophilic attack of sulfur atom. Computational results suggest that the more stable product is CysQX5 (Gibbs free energy variation of – 26.78 kcalmol-1), and it could be formed from two distinct intramolecular cyclization paths: i) from the monosubstituted product CysQX1; ii) from disubstituted product CysQX3. At the time, transition states of all processes involving in the reactions of DCQX and CYsMe are being evaluate, including the possibility of Smile-type rearrangements.

12
  • EDSON DE OLIVEIRA LIMA FILHO
  • Synthesis of Amino-N-heteroaromatic via SNAr

  • Advisor : LIVIA NUNES CAVALCANTI
  • COMMITTEE MEMBERS :
  • LIVIA NUNES CAVALCANTI
  • RENATA MENDONÇA ARAUJO
  • IVANI MALVESTITI
  • Data: Feb 19, 2018


  • Show Abstract
  • N-heteroaromatic derivatives containing amine groups in their structures are of great interest in the development of new drugs, due to the reported biological activities that these compounds present. The development of novel protocols for obtaining amino-N-heteroaromatic compounds in a mild manner and without the use of metal catalysts is much desired in synthetic organic chemistry. In this work a method was developed to obtain quinoxalinic derivatives through a SNAr reaction using 2,3-dichloro-6,7-dinitroquinoxaline (DCDNQX) and substituted anilines. After optimization, 13 examples of unpublished products were obtained under mild conditions and without the use of metallic catalysts, with yields varying from low to excellent (trace-98%). In addition to the use of the quinoxaline derivative DCDNQX, the C-H functionalization reaction with pyridine and t-butylamine was studied. The use of molecular iodine (I2) as an additive in this transformation allowed the formation of a dissubstituted product. A preliminary analysis of the results indicates that this dissubstitution occurs at the C3 and C5 or C2 and C6 positions of the pyridine ring, a reactivity rarely seen in reports in the literature, which may lead to the formation of novel compounds with potential biological activity.

13
  • BRUNA LUIZA BATISTA DE LIMA
  • Copolymers of Partially Hydrolyzed Polyacrylamide Grafted with Poly(ethylene oxide-co-propylene oxide) (HPAM-g-PEOPPO): Synthesis, Characterization and Properties Studies

  • Advisor : ROSANGELA DE CARVALHO BALABAN
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • JOSÉ MANOEL MARCONCINI
  • ROSANGELA DE CARVALHO BALABAN
  • Data: Jul 19, 2018


  • Show Abstract
  • The objective of this work was to prepare and characterize thermoassociative copolymers of HPAM-g-PEOPPO, by grafting the poly(ethylene oxide-co-propylene oxide) – PEOPPO (EO/PO = 19/03) onto the backbone of a partially hydrolyzed polyacrylamide (HPAM) For this purpose, the copolymers were prepared in water by a coupling reaction between HPAM and PEOPPO, using EDC/NHS as condensing agents. Structural characterization was carried out through infrared (IR) and 1H NMR spectroscopy. Thermal stability on solid state was evaluated by thermogravimetric analysis (TGA). The evaluation of the properties in aqueous media of different salinities was made through ultraviolet-visible (UV-Vis)and rheological measurements. The characteristic functional groups peaks for all polymers were observed through infrared spectra. By 1H NMR spectra was possible to confirm that the copolymers were successfully synthesized and to determine the degree of grafting. TGA data demonstrated that copolymers were thermally more stable HPAM. UV-Vis showed that HPAM did not exhibited change in transmittance with temperature for none of the aqueous media studied but their grafted derivatives turned turbid in the presence of salt. Rheological measurements showed that copolymers exhibited thermothickening behavior in saline media and higher apparent viscosity than HPAM above 70 °C. All results suggest HPAM-g-PEOPPO as an interesting candidate for enhanced oil recovery.

14
  • ISABELLE MARIANE DE LIMA FERREIRA
  • CATALYTIC PYROLYSIS OF MICROALGAE BIOMASS TO OBTAIN RENEWABLE FUELS USING MESOPOROUS MATERIALS WITH NICKEL AND MOLYBDENUM

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • SIBELE BERENICE CASTELLA PERGHER
  • LUZIA PATRICIA FERNANDES DE CARVALHO GALVAO
  • VINÍCIUS PATRÍCIO DA SILVA CALDEIRA
  • Data: Jul 24, 2018


  • Show Abstract
  • The use of microalgae has been prominent in the context of sustainable innovation in order to use them for the production of biofuels, due to its great biomass production capacity and its cultivation developed in adverse conditions, such as in wastewater. Therefore, the synthesis and characterization of the mesoporous material AlSBA-15, with the incorporation of nickel and molybdenum metals, was studied in order to optimize the pyrolysis products of the microalgae biomass for the generation of renewable fuels. The catalysts were synthesized and characterized by XRD, FTIR, TGA / DTGA thermal analysis and SEM with EDS. The microalgae biomass was characterized by elemental analysis (CHN) and TGA. The catalysts presented reflections on X-ray diffractograms, characteristic of the highly ordered P6mm hexagonal structure of the SBA-15, demonstrating that the incorporation of the metals did not modify the structure of the molecular sieve. The spectrum of the catalyst showed bands in the regions of 1050 and 800 cm -1, related to the symmetrical and asymmetric elongation of the O-Si-O bonds and, at 950 and 460 cm -1, attributed to the Si-OH bond elongation and the deformations Si-O-Si, common in silicate materials. And, the mapping via EDS evidenced the presence of nickel and molybdenum metals in the structure of AlSBA-15. The thermogravimetric analysis of Fourier transform infrared (TG-FTIR) was performed to show a prediction of the gaseous products obtained by the temperature range. Thus, it was found that from 300 ° C appeared bands with vibration peaks centered between 2400 and 2250 cm -1 attributed to the stretching vibrations of the functional group C = O, referring to CO2 molecules. Where the best results with very high bands were obtained when the microalgae biomass sample was in the presence of the catalysts with nickel and molybdenum metals, an indicative of deoxygenation by decarboxylation, which reflects an improvement of the fuel produced.

15
  • ANDRÉ HERCULANO DE OLIVEIRA
  • SYNTHESIS OF NOVEL PI-EXTENDED AZA-HETEROCYLES FOR APPLICATIONS AS ADVANCED MATERIALS

  • Advisor : FABRICIO GAVA MENEZES
  • COMMITTEE MEMBERS :
  • FABRICIO GAVA MENEZES
  • LIVIA NUNES CAVALCANTI
  • WELMAN CURI ELIAS
  • Data: Jul 25, 2018


  • Show Abstract
  • In recent years advanced molecular materials such as OLEDs and Liquid Crystals derived from heterocyclic compounds have propelled the branch of the Organic-Electronics for their applications as organic semiconductors. In this context, this work aims to synthesize, characterize and evaluate the potential of new organic materials for applications such as semiconductors, derived from the azaheterocyclic nuclei benzimidazole, quinoxaline and phenazine, functionalized with alkyl side chains. The benzimidazole, quinoxaline and phenazine nuclei acting as building blocks were: 4- (1H-benzo [d] imidazol-2-yl) -phenol, 1,4-dihydroquinoxaline-2,3-dione, phenazine-2,3 diol. The side chain insertions in these nuclei occurred via alkylation reactions (N, N, N, N, O and O, alkylations), the dodecyl bromide was used as the source of the alkyl units. As alkylated functionalized derivatives, 1-Dodecylquinoxaline-2,3 (1H) dione, 1-4-didodecylquinoxaline-2,3 (1H, 4H) -dione, 2- (4- (dodecyloxy) phenyl) -1H-benzo [ d] imidazole, 1-dodecyl-2- (4- (dodecyloxy) phenyl) 1H-benzo [d] imidazole, and 2,3-bis (dodecyloxy) -phenazine. All derivatives were suitably characterized by IV-ATR, 1 H and 13 C nuclear magnetic resonance. As expected, after addition of the alkyl chains the novel derivatives had lower melting points than the starting compounds. Regarding the synthetic step, the methodologies used were satisfactory and with good yields. Two of the synthesized compounds were selected for investigation of their thermal behavior by polarized optical microscopy and differential scanning calorimetry. Compound 2-(4- (dodecyloxy) phenyl)-1H-benzo[d]imidazole was found to present smectic-type liquid crystalline between 85 oC and 172 oC.

16
  • GABRIELLA SOUSA DE MELO QUEIROZ
  • PRODUCTION OF RENEWABLE HYDROCARBONS FROM THE CATALYTIC DEOXYGENATION OF MACAÚBA OIL (Acrocomia aculeata) USING THE MESOPOROUS MATERIALS AlSBA-15 E Mo / AlSBA-15

  • Advisor : AMANDA DUARTE GONDIM
  • COMMITTEE MEMBERS :
  • AMANDA DUARTE GONDIM
  • DJALMA RIBEIRO DA SILVA
  • EDJANE FABIULA BURITI DA SILVA
  • Data: Jul 26, 2018


  • Show Abstract
  • The demand for renewable energy resources has led to an increase in research for biofuels obtained from vegetable oils. In this context, vegetable oils that are not used for foodstuffs, such as macaúba oil, have shown promising. For the obtaining renewable hydrocarbons from macaúba, processes such as pyrolysis or cracking can be used, which in turn produces oxygenated compounds, leading to the search for catalysts that allow the conversion of these compounds into hydrocarbons. Thus, in the present work, the synthesis of AlSBA-15 catalyst and the subsequent impregnation with molybdenum were carried out in order to obtain renewable hydrocarbons from the catalytic deoxygenation of macaúba oil. The characterization of the catalysts was performed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) coupled with X-ray Dispersive Energy (EDX) analysis and Spectroscopy in the Infrared Region Fourier (FTIR). The catalysts showed reflections on the X-ray diffraction characteristic of the highly ordered hexagonal P6mm structure of the mesoporous material SBA-15 demonstrating that the incorporation with metal did not damage the structure of the molecular sieve. The infrared spectrum showed bands characteristic of SBA-15 type materials, such as 1088 cm-1, 804 cm-1 and 467 cm-1 bands referring to the asymmetric, symmetrical vibrational stretching and the Si-O-Si bond present in the structure of the SBA-15, respectively. Additionally, the presence of a 964 cm-1 band associated with the stretching of the Si-OH bond of the silanols groups composing the structure of the mesoporous material was verified. The TGA-FTIR analysis of pure and esterified macauba oil was performed with and without the presence of the catalysts that brings the products obtained in the pyrolysis through the characterization by Spectroscopy in the Infrared Region by Fourier Transform and by the thermal degradation of macaúba oil , allowing a better understanding of pyrolysis results. The results obtained by TGA-FTIR of the samples with the catalysts showed bands in the range of 2400-2250 cm-1  referring to the C = O bond of the CO2 group, which led to the conclusion that AlSBA-15, and especially Mo / AlSBA-15 catalysts, resulted in the deoxygenation of macaúba oil with the consequent production of hydrocarbons.

17
  • TAIZA NAYARA DA SILVA CARIDADE
  • PHYTOCHEMICAL AND BIOLOGICAL STUDY OF FOUR DIFFERENT SPECIES OF Waltheria GENUS

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • RENATA MENDONÇA ARAUJO
  • LIVIA NUNES CAVALCANTI
  • ROSA VIRGÍNIA SOARES MAMEDE
  • Data: Jul 27, 2018


  • Show Abstract
  • The genus Waltheria belongs to the family Malvaceae, which is composed of 243 genera and 4225 species distributed in different regions of the world, mainly in tropical regions of South America. Its popular use is vast, and its species are used in the treatment of ulcers, hemorrhoids , asthma, diarrhea, in addition to presenting high antioxidant, anticancer, anti-inflammatory and anticonvulsive activity. Species of this genus are rich in flavonoids, terpenes, alkaloids, cyclopeptides, among other secondary metabolites. The phytochemical study of the aerial parts and stem of different Waltheria species led to the isolation of a pentacyclic triterpene of lupan type, 3-oxolup-20 (29) -en-28-oic acid (betulonic acid), four flavonoids: 5- hydroxy-3,3,4,4-trimethoxyflavone, canferol-3-O-β-glucopyranoside, glycopyranoside and canferol-3-O-β-hydroxy-3,3 ', 4' (6 '' - cumaroyl) -glycopyranoside (tyloside), both unpublished for the species studied. In addition to the N-benzoyl-2-amino-3-phenylpropyl N-benzoyl-L-phenylalaninate dipeptide known as auranamide, unheard of for the genus studied. The study of dereplication of the studied strata showed that flavonoids are major metabolites in the species collected in the northeast, diverging from the study carried out in the south of the country, which may be related to the influence of abiotic factors. A preliminary toxicity test of the extracts with Artemia salina revealed the low toxicity of the studied species with LD50 of greater than 1000 μg / mL, in addition to high antioxidant activity against the DPPH radical, especially Waltheria douradinha, which presented superior activity to the other species studied.

18
  • ELVIS LOPES BRITO
  • SUPERPARAMAGNETIC MAGNETITE/INTERPOLYELECTROLYTE COMPLEX COMPOSITES

  • Advisor : JOSE LUIS CARDOZO FONSECA
  • COMMITTEE MEMBERS :
  • JOSE LUIS CARDOZO FONSECA
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • JOÃO MARIA SOARES
  • Data: Aug 10, 2018


  • Show Abstract
  • Magnetite nanoparticles are one of the most studied magnetic materials due their extremely low toxicity, superparagnetic behavior at room temperature and low costs, with potential for wide use in medical application as drug release, hyperthermia and magnetic separation. The functionalization of magnetite nanoparticles has been extremely promising in recent decades, since it causes dimensional and chemical modifications on the surface of the particles, taking them to new applications. Chitosan (CS) are widely used to improve biocompatibility of magnetic particles, in order to yield particle systems more adequate for application in biomedicine. CS has amino groups in its macromolecular structure, which in acid condition become protonated, resulting in positive  groups so that it can be used as coating for particles as well as in the preparation of polymer network composites. In this work, magnetic composites (CMs) were obtained by chemical precipitation between CS and poly (sodium 4-styrenessulfonate) NaPSS in presence of magnetite nanoparticles, which was studied for (SO3-/NH3+) molar ratios of 1.43 and 0.7. in order to compare, Interpolyeletrolyte complexes (IPECs) were prepared with the same proportion and without the presence of magnetite nanoparticles. Composite composition and magnetite microstructure were investigated by termogravimetric analysis (TGA), Fourier transformed Infrared spectroscopy (FTIR), X-ray powder Diffraction (DRX), Transmission electron microscopy (TEM) and zeta potential (). Magnetic characterization was performance by Field cooled (FC) and zero Field Cooled (ZFC) magnetization experiments, as well as magnetic hysteresis measured in different temperature. TGA and FTIR confirmed the presence of CS, PSS and magnetite in all composites, furthermore, the thermal event verified in TGA results for CMs agree with IPECs structure. DRX and TEM showed that magnetite had no change their structural features during the preparation of composites, being approximately 12 nm for all samples. Composite surface charge was altered according to (SO3-/NH3+) molar ratio, being positive for the composite with ratio 1.43 and negative for ratio 0.7 (). The magnetic characterization shows that both CMs are superparamagnetic in room temperature (25°C).

19
  • EMERSON CARNEIRO DA SILVA
  • RECOVERY OF METALS IN PRINTED CIRCUIT BOARDS

  • Advisor : ADEMIR OLIVEIRA DA SILVA
  • COMMITTEE MEMBERS :
  • ADEMIR OLIVEIRA DA SILVA
  • SIBELE BERENICE CASTELLA PERGHER
  • JARLEY FAGNER SILVA DO NASCIMENTO
  • Data: Aug 10, 2018


  • Show Abstract
  • The growth and technological upgrades, which occur uncontrollably each day, lead to an increase in the production and consumption of new electro/electronic devices, as a consequence, the growth of waste produced by the disposal of such equipment (e-waste). Disposal of this waste may pose a great risk to the environment because it contains toxic chemicals. The development of techniques with the objective of recovering the metals present in the electronic waste is of extreme importance, aiming at the economic power generated and also the reduction in environmental impacts. The highest concentration of the metals present in the electronic equipment are found in the printed circuit board, with this, the accomplishment of this work has as objective the separation, identification and recovery of the metals present in printed circuit boards of obsolete computers, where starting from alkaline leaching (NaOH 2 mol/L) and acid (HCl 12 mol/L and HNO3 14 mol/L) the metals were oxidized, separated into three different solutions (hydroxides, chlorides and metal nitrates) and characterized by inductive plasma coupled emission spectrometry (ICP-AES). From the three solutions, different methods were applied to recover the metals: dehydration of the solution of metal hydroxides (aluminum oxide): electrowinning solution of metallic chlorides (copper, tin and lead); and the reaction of the solution of metallic nitrates with NH4OH (nitrate of tetramincupre (II)). The solid materials obtained are analyzed by X-ray fluorescence, with yields of up to 94.74% copper, 70.21% tin and 37.55% recovered lead.

20
  • LETÍCIA GRACYELLE ALEXANDRE COSTA
  • DEVELOPMENT AND VALIDATION OF METHODOLOGY TO DETERMINE ANTITUBERCULOSIS DRUGS IN HOSPITAL EFFLUENT

  • Advisor : DJALMA RIBEIRO DA SILVA
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • TEREZA NEUMA DE CASTRO DANTAS
  • ELISAMA VIEIRA DOS SANTOS
  • RICARDO HENRIQUE DE LIMA LEITE
  • Data: Aug 28, 2018


  • Show Abstract
  • Drugs are the group of emerging contaminants that have been receiving attention in recent years, with hospital effluents being the predominant source of introduction into the environment. The main concern related to the presence of these compounds in the environment is due to the development of bacterial resistance. The antibiotics stand out because of their intensive use, and it can be emphasized those that fight Tuberculosis considered one of the biggest problems of health worldwide. In view of this conjuncture, it was proposed to develop and validate a liquid chromatography metodology coupled to tandem mass spectrometry with electrospray ionization for the analysis of anti-tuberculosis drugs via direct injection in hospital effluent samples. The developed method complied with all required validation parameters. The method robustness was evaluated through the Youden test, which allowed to determine that the best chromatographic condition was the one using mobile phase flow of 0.150 mL min-1, column temperature of 25°C, without sample acidification and using Acclain Polar Advanced (C16). The method presented good linearity in the working range of 0.1 to 100 μg L-1 with R2 values higher than 0.9632 for the four drugs. The method was shown to be sensitive, accurate, robust and with recoveries in accordance with INMETRO, above 80%. LDs and LQs were respectively 0.028 and 0.057 μg L-1 for Pyrazinamide, 0.094 and 0.176 μg L-1 for Isoniazid, 0.416 and 0.833 μg L-1 for Rifampicin and 0.263 and 0.519 μg L-1 for Ethambutol. Regarding Hospital Effluent samples, no Ethambutol was detected in any samples, while Isoniazid was determined in all samples at concentrations between 3.25 and 23.09 μg L-1. Therefore, it can be concluded that the developed method can be applied for determination of these pharmaceutical compounds with high precision and sensitivity.

21
  • VALDIVINO FRANCISCO DOS SANTOS BORGES
  • REMOVAL OF METAL ICONS OF EFFLUENTS USING BENTONITAS AND DIATOMITA TREATED WITH MICROEMULSIONS

  • Advisor : ALCIDES DE OLIVEIRA WANDERLEY NETO
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • SIBELE BERENICE CASTELLA PERGHER
  • MONICA RODRIGUES DE OLIVEIRA
  • Data: Sep 3, 2018


  • Show Abstract
  • Heavy metals have been contributing significantly to water pollution, interfering temporarily or permanently in the maintenance of aquatic biota. Industrial development contributes to water pollution by contaminating rivers, lakes and seas with heavy metals. The use of natural and chemically treated adsorbents has been an alternative in the capture of metallic ions present in aquatic environments through the adsorption process. The objective of this work was to evaluate the adsorption capacity of iron, lead and chromium ions present in synthetic solutions using commercial bentonite, sodium bentonite and diatomite in their natural forms and treated with micellar solution and microemulsion. The surfactant studied was Ultrol L-90, which together with n-butanol, kerosene and distilled water obtained a formulation consisting of direct micelle. After the treatment of the natural adsorbents with micellar solution and microemulsion, the characterizations were made by the techniques of X-ray Fluorescence (XRF), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), N2 adsorption specific área (BET), Differential and Thermogravimetric Thermal Analysis (DTA/TGA) and Fourier Transform Infrared Spectroscopy (FTIR). The adsorption study of the metals showed that the treatment with the micellar solution does not modify the capture capability, being the efficiency almost equal to the natural adsorbents. While the treatment with the microemulsion significantly increases the percentage of adsorption efficiency, reaching 99% for iron and lead ions, and 83% for the chromium ion when the diatomite is present.

22
  • DANIEL SEGUNDO XAVIER DA FONSECA
  • CHEMICAL STUDY OF LIPID FRACTIONS AND ACETATE FRACTIONS OF MARINE SPONGES Agelas dispar, Chondrilla nucula, Aplisyna fulva, Desmapsamma anchoratae Topsentia ophiraphidites and Cinachyrella apion E ANTIFUNGAL ACTIVITY TEST OF LIPID FRACTIONS

  • Advisor : RENATA MENDONÇA ARAUJO
  • COMMITTEE MEMBERS :
  • RENATA MENDONÇA ARAUJO
  • LIVIA NUNES CAVALCANTI
  • LEANDRO DE SANTIS FERREIRA
  • LILIAN GRACE DA SILVA SOLON
  • Data: Sep 6, 2018


  • Show Abstract
  • Fatty acids (AGs) are naturally occurring metabolites found in all parts of living things, and marine sponges have large amounts of GAs. Interest in these compounds arose in the 1970s, and has increased, since sponges have very rich chemical AGs, and are the source of a diverse variety of chemical structures. The study of spongy lipids is as important as other secondary metabolites. The structures were confirmed by gas chromatography coupled to GC-MS mass spectrometry through their methyl esters, using 2 series of GA standards and 4 libraries in addition to the fragmentation profile. Identification was performed through similarity and analysis of mass spectra. These results highlight the high capacity of AG synthesis by these organisms, being superior to other living organisms. Thus, the lipid profile of six sponges of the species Agelas dispar Chondrilla nucula, Topsentia ophiraphidites, Cinachyrela apion and Aplisyna fulva of the northeast coast of Brazil. The species Aplysina fulva, Topsentia ophiraphidites and Cinachyrella apion were investigated for the first time, and the species Agelas diapar, Chondrilla nucula and Desmapsamma anchorata were reexamined for their composition of fatty acids. The data revealed more than 100 fatty acids, some unheard of for the sponge species studied in this study, such as Hydroxylated acids, in Chondrilla nucula and Aplysina fulva. 4,8,12-Trimethyltridecanoic acid and 3,7,11,15-tetramethylhexadecanoic acid (phytanic) polymers known as isoprenoid acids have been identified. Among the unsaturates identified include acids with a substitution pattern Δ5.9, contribute significantly to the amount of polyunsaturated fatty acids of sponges, (5Z, 9Z) -23-methyl-5,9-tetracosadienoic acid being the only one to have branching with this replacement pattern. The present work also evaluated the antifungal activity of the lipid fractions by means of the microdilution test in broth, obtaining satisfactory results for the lipid fraction of the species Aplysina fulva.

23
  • THIAGO YURI BARRETO DE OLIVEIRA
  • GLYCEROL OXIDATION WITH SILVER IONS AT LOW TEMPERATURE

  • Advisor : LUIZ HENRIQUE DA SILVA GASPAROTTO
  • COMMITTEE MEMBERS :
  • LUIZ HENRIQUE DA SILVA GASPAROTTO
  • FABRICIO GAVA MENEZES
  • ADONAY RODRIGUES LOIOLA
  • Data: Sep 10, 2018


  • Show Abstract
  • Glycerol is a highly functional compound that has three hydroxyl groups in its structure, which is why in its oxidation process many high value-added products can be formed. The main objective of this work was to perform the catalytic oxidation of glycerol at low temperatures through homogeneous catalysis. The process performed in aqueous and basic solution had as oxidizing agent and catalysts the silver ions. It was studied how the variation of the initial concentrations of the reactants, the pH and the temperature influence in the conversion rate of the glycerol in the products formed and in the selectivity to those products. These results were analyzed by means of Gas Chromatography, the identification of the products of catalytic oxidation of the glycerol was made by High Performance Liquid Chromatography, and by means of Inductively Coupled Plasma Optical Emission Spectrometry, the consumption percentage of silver ions to metal silver was analyzed. For this analysis, the results indicate that a good part of the samples obtained high consumption percentage. Some results of Gas Chromatography point to an inversely proportional relation between the conversion rate of glycerol in its oxidation products and the selectivity to these products. It was observed that in three samples, which had the initial low glycerol concentration, the conversion rate was 100%, thus confirming that, in high quantity, glycerol inhibits its own oxidation process. The identification of the products showed mesoxalic acid as the major product of this study.

24
  • ANDREY COSTA DE OLIVEIRA
  • INFLUENCE OF ACID CONCENTRATION OF MICROEMULSIONED AND NANOEMULSIONED SYSTEMS ON ADVANCED OIL RECOVERY

  • Advisor : TEREZA NEUMA DE CASTRO DANTAS
  • COMMITTEE MEMBERS :
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • RICARDO PAULO FONSECA MELO
  • TEREZA NEUMA DE CASTRO DANTAS
  • VANESSA CRISTINA SANTANNA
  • Data: Oct 26, 2018


  • Show Abstract
  • One of the main reasons that leads to the development of technologies for the oil recovery is the high remaining oil percentage in the well after primary and secondary recovery, and these are no longer able to recover it. In this work, microemulsion systems and acid nanoemulsions will be used in advanced recovery processes. The systems present in its composition: surfactant, co-surfactant, kerosene and acid solution with different concentrations. The used surfactant is commercial and of not-ionic character. The acid, when reacting with the carbonated rock, tends to open the possible pores that still are closed for certain particles or until forming new canals, increasing the permeability of the rock. The used systems had differed only in the acid concentration in watery phase that contained 1.5% of HCl, 5%, 10% and 15%. The concentrations that compose the systems were chosen through the mounted ternary diagram, the systems contain 80% of aqueous phase, 2% of oil phase, 12% of surfactant and 6% of cosurfactant. After to have definitive this point, all the systems were characterized by its superficial tension, viscosity, corrosive capacity, c.m.c., diameter of the particle and speed of reaction between acid and rock. After the this, the efficiency of the recovery of each system in a simulator of the reservoir with controlled temperature and the pressure had been measured, them had presented the following recovered oil percentages: 28%, 39%, 44% and 48% for the systems with 1,5%, 5%, 10% and 15% of HCl, respectively. In this manner, was concluded that how much bigger the concentration of the acid one, plus it tends to increase the permeability of the rock and to increase the recovery efficiency. Finally, was made a nanoemulsion of the microemulsion system more efficient (system 4), it was characterized in the same way that too much systems, presenting 84% of recovered oil. It was concluded that acidic microemulsion and nanoemulsion are afficient systems when when applied in the advanced with the advantage of permeating the rock is a more homogeneous way and reducting the corrosion of the equipament in values up to 60%, constituting an alternative for application in the area.

25
  • ALEXSANDRO LIMA DOS ANJOS
  • SYNTHESIS AND CHARACTERIZATION OF MOLYBDENUM(VI) COMPLEXES WITH NITROGENATED LIGANDS

  • Advisor : ANA CRISTINA FACUNDO DE BRITO PONTES
  • COMMITTEE MEMBERS :
  • ANA CRISTINA FACUNDO DE BRITO PONTES
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • CLEIDE MARIA DA SILVA LEITE
  • Data: Nov 1, 2018


  • Show Abstract
  • Molybdenum is a metal that is present in the human body and performs various functions, such as assisting catalytic redox processes and transfer of oxygen atoms between various substrates. In addition, this metal are widely used to obtain new compounds with biological activities or catalysts in epoxidation reactions. Therefore, the present work aims to the synthesis and characterization of cis-dioxo molybdenum(VI) complexes with ligands 1,10-Phenantroline (phen), Azide (N3­-) and Metformin (met). Thus, the cis-[Mo(phen)(O)2Cl2], cis-[Mo(phen)(O)2(N3)2] and cis- [Mo(met)(O)2Cl2] compounds were obtained from the precursor cis-[Mo(DMSO)2(O)2 Cl2]. The compounds were obtained based on methodologies described in the literature and by adaptation of procedures of synthesis of similar complexes. The characterization was performed using spectroscopic (Infrared and Uv-vis), electrochemical techniques and thermal analysis. Based on the analysis of the vibrational spectra it was possible to verify the presence of the characteristic absorptions for compounds containing the oxide ligands, through Mo=O stretch, with bands on 919 and 891 cm-1 for the precursor, 933 and 896 cm-1 for complex with the ligand phen, 915 and 885 cm-1 for azido complex and 947 and 891 cm-1 for complex with metformin. In addition to variation in the main absorptions of the other ligands, showing coordination with the metal. The electronic spectra, obtained in water, did not present d-d transitions, the molybdenum is in maximum oxidation state (6+). Only the LMCT bands for chlorines at 213 and 234 nm were verified, in addition to other LMCT at 272 nm for for the DMSO. The complexes containing the phenanthroline ligand presented characteristic intraligand bands for the system. The Cyclic Voltammetry analysis showed irreversible and quasi- reversible processes corresponding to the one- and two-electron sequencial transfers, as well as the variation of the metal redox potential due to the exchange of ligands depending on the π-donor or π-acceptor character of the ligand. Based on the thermal analysis, it was possible to evaluate the stability of the compounds and the influence of the ligands on the main characteristics of the system, especially the initial decomposition temperature of the complexes formed. Thus, the set of techniques provided a correlation between the donor capacity of the oxo groups and the influence of ligands with different characteristics, showing how the electronic density around the metal can vary.

26
  • MAYARA JANE CAMPOS DE MEDEIROS
  • SPECTROSCOPIC, ELECTROCHEMICAL AND CYTOTOXIC EVALUATION OF COPPER (II) COMPLEXES WITH TRIDENTATE LIGANDS

  • Advisor : ANA CRISTINA FACUNDO DE BRITO PONTES
  • COMMITTEE MEMBERS :
  • ANA CRISTINA FACUNDO DE BRITO PONTES
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • JOSÉ CARLOS VIEIRA DE MIRANDA
  • Data: Dec 18, 2018


  • Show Abstract
  • Copper complexes have shown relevant cytotoxic activity, participating in the reactions responsible for DNA breakage and consequent cell death. Thus, the present work aims at the synthesis and characterization of 4-({bis[pyridin-2-yl)methyl]amino}methyl)-7-hydroxy-2H-1-benzopyran-2-one (L1) and N,N-Bis(2-hydroxy-naphthylmethyl)methylamine (L2) and [Cu(phen)(L1)](PF6)2 and [Cu(phen)(L2)] complexes, referred to as C1phen and C2phen, respectively, obtained from the precursor [Cu(phen)Cl2]. The results of IR and NMR indicated the formation of L1 and L2. For the C2phen complex, the IV showed the coordination of L2 to the metal due to the absence of νO-H, whereas for the C1phen it was possible to confirm its formation through the characteristic vibrational modes. The UV-vis showed a shift of the d-d transition to the more energetic region compared to the precursor complex. The emission spectrum confirmed that the [Cu(phen)(L1)](PF6)2 and [Cu(phen)(L2)] complexes exhibited fluorescence, even after coordination, whereas the electrochemistry showed for the compound C2phen two quasi-reversible redox processes Cu2+/1+ and Cu1+/0. For the C1phen it was possible to visualize only the process related to the Cu2+/1+ redox pair in the applied potential range. The cytotoxic potential of the complexes of interest was evaluated with two human tumor cell lines (A2058 and SiHa) by the MTT assay using the IC50 as the parameter. Like the complexes, the ligands also induced a concentration-dependent cytotoxic effect, however, the complexes demonstrated the highest cytotoxic response. Cell death and cell cycle were also assessed by flow cytometry, where C1phen and C2phen complexes mainly induced late apoptosis. Through the cell cycle, it was possible to conclude that for the SiHa, the C1phen complex inhibited the progression of the cycle in the S phase, whereas for the A2058, both C1phen and also for C2phen, the interruption occurred in the G2-M phase. Therefore, with the biological results, it is possible to suggest a possible application in the treatment of cancer.

Thesis
1
  • ALEXSANDRO JHONES DOS SANTOS
  • Treatment of water contaminated with azo dyes by the application of advanced oxidative processes: photochemical, electrochemical and photoelectrochemical using UVA and solar radiation

  • Advisor : CARLOS ALBERTO MARTINEZ HUITLE
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • ALCIDES DE OLIVEIRA WANDERLEY NETO
  • DOUGLAS DO NASCIMENTO SILVA
  • CARMEM LUCIA DE PAIVA E SILVA ZANTA
  • SUELY SOUZA LEAL DE CASTRO
  • Data: Jan 29, 2018


  • Show Abstract
  • Advanced oxidation processes (POAs) are promising technologies for environmental remediation. These technologies are based on the high oxidation power of hydroxyl radicals (OH), which have a high reactivity to oxidize organic compounds present in liquid effluents.

    In this thesis, the application of different POAs to treat synthetic and real solutions containing azo dyes has been studied. These compounds present a serious socio-environmental risk since they have high toxicity and are resistant to conventional treatment methods. The obtained results were divided into four distinct chapters. In chapter 1, two valuable natural resources of Brazil were used, namely, the sun in the Northeast region and the niobium. By combining these two goods, it has been found that solar photocatalysis whith niobium oxide (Nb2O5) is an effective and economical method for discoloring dyes at low concentrations. The photocatalytic efficiency of Nb2O5 was evaluated by varying the concentrations of dye, H2O2, Nb2O5 and pH. The best operating conditions were 1 g L-1 of Nb2O5, 5 mg L-1 of dye and 0.20 M of H2O2 and pH 5. At the end of five treatment cycles, Nb2O5 photocatalyst efficiency remained constant. In the case of chapters 2, 3 and 4, electrochemical and photoelectrochemical treatments using UVA and solar radiation were used. In chapter 2, a solution containing the dye diazo Pounceau SS was treated using a pre-pilot flow plant equipped with boron doped diamond (BDD) or platinum (Pt) anode and air diffusion cathode, connected to a photoreactor containing a 160 W UVA lamp. Anodic oxidation with H2O2 electrogenerated (AO-H2O2) was more efficient with BDD, due to the greater oxidation capacity of heterogeneous OH radicals formed on its surface. In electro-Fenton (EF) and photo electro-Fenton (PEF), the OH radicals produced by Fenton’s reaction were more reactive. The PEF had a better performance due to the additional photolysis of intermediates and photodecarboxylation of Fe (III) complexes with UVA light. The influence of light minimized the effect of the anode in the process, which was relevant in AO-H2O2 and EF processes. Chapter 3 had the objective of evaluating the influence of water hardness on the treatment of the color of eriochrome black T  by means of the EF process. The dye molecule forms complexes with calcium and magnesium. These complexes being stable make electrophilic attack of OH radicals difficult. Thus, water hardness should be an highlihted parameter in the EF process. In chapter 4, it was taken into account that daily activities as the washing of clothes generate dyes that need to be treated. A viable alternative is to consider the wastewater treatment at a domestic scale. Therefore, an actual laundry washing machine effluent was treated by advanced electrochemical oxidation processes, demonstrating high efficiency and could be applied as decentralized small scale treatment devices. The solar PEF has shown to be a suitable process for complete removal of color and organic matter after 240 min of treatment applying a current density of 66.6 mA cm-2. The POAs studied in this work proved to be satisfactory and sustainable technologies for the treatment of liquid effluents.

2
  • ADRIANA PAULA BATISTA DOS SANTOS
  • Alkaline hydrothermal synthesis of La(OH)3 nanotubes and CeO2 nanotubes and study of the influence of the synthesis parameters about its physicochemical properties

  • Advisor : ANTONIO SOUZA DE ARAUJO
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • TIAGO PINHEIRO BRAGA
  • ANNE GABRIELLA DIAS SANTOS
  • GERALDO EDUARDO DA LUZ JUNIOR
  • LUIZ DI SOUZA
  • Data: Feb 27, 2018


  • Show Abstract
  • Nanotubes 1D consisting of La(OH)3 and CeO2 obtained by hydrothermal synthesis, has attracted much interest recently, due to their detachable physical-chemical characteristics and potential applications. Due to its tubular structure with three different contact surface (inner, outer surface and tube ends), high surface area, low density and good load transfer ability. The hydrothermal method has been widely used to obtain this type of nanostructures, since it is a simple technique in which the properties of the products obtained depend on the formation mechanism and the hydrothermal conditions used. Thus, La(OH)3 and CeO2 nanotubes were synthesized using alkaline hydrothermal synthesis, free from templates. The effect of the synthesis conditions used, as NaOH concentration in the reaction medium, temperature and time of synthesis, as well as the calcination conditions were discussed on the formation of the nanotubular morphology and its properties, in the two types of nanotubes. This route to obtain nanostructures, besides the lower cost, and to treat in a more environmentally correct way, allows a greater degree of control over the size and properties of the obtained nanotubes. The results of this study were divided into three chapters, in which chapter 1, through patent of invention, presents the results obtained for the synthesis of La(OH)3 nanotubes, with the influence of the synthesis conditions on the obtained morphology. The main results for this type of material showed that in all the synthesis conditions used, high yield of the nanotubular morphology were obtained, in which the materials in all cases were composed of La(OH)3, organized in hexagonal form, which differed in the size of their external diameters. It was also observed that the higher the temperatures, the synthesis time and the NaOH concentration, the higher the diffraction peak intensities, indicating a larger structural organization, when these parameters were increased. The chapter 2, show an article that exposes the influence of calcination on the physicochemical properties of nanotubes of La(OH)3. The results showed that the calcination temperature influences the organization, composition, and texture properties of the nanotubes obtained. The hydrated material consisting of La(OH)3 with hexagonal structure was obtained after the hydrothermal synthesis and was maintained after the calcination process at 750 ° C. However, the nanotubular morphology was destroyed after this process. Calcination at 450 ° C generated a La2O2CO3 composite material with a mixture of symmetries (hexagonal and tetragonal), in which the nanotubular morphology was preserved. The calcined nanostructures presented specific surface areas of 45 and 25 m2.g-1, when calcined at 450 and 750 °C, respectively. Thus, nanotubes consisting of La(OH)3 can be obtained by alkaline hydrothermal synthesis, without templates, which can have their composition and properties altered, through the calcination process, according to their catalytic application. Chapter 3 presents the influence of the synthesis parameters (NaOH concentration on the reaction medium and temperature and time of synthesis) and of calcination process on its physicochemical properties of CeO2 nanotubes. Hydrated nanotubes consisting of CeO2 with cubic fluorite structure were obtained in all cases, in which hydration, size of nanostructures, and oxygen vacancies varied according to the synthesis condition used, providing materials with different catalytic activities. The mechanism of formation of CeO2 nanotubes was discussed. However, the results of these three chapters show for the first time the dominance over the formation, composition and size of the nanotubular morphologies of La(OH)3 and CeO2 obtained by this route, through the control of these synthesis parameters and the calcination process. This is of fundamental importance in order to obtain nanotubes with characteristics according to future applications in catalysis, sensors and electronic devices.

3
  • VERONICA DA SILVA OLIVEIRA
  • Study of the Fe-cyclam system with carboxylate ligands and evaluation of the spin crossover effect and antibacterial activity of the [Fe(cyclam)ox]PF6 complex

  • Advisor : ANA CRISTINA FACUNDO DE BRITO PONTES
  • COMMITTEE MEMBERS :
  • FRANCISCO ORDELEI NASCIMENTO DA SILVA
  • DANIEL DE LIMA PONTES
  • MARCO ANTONIO MORALES TORRES
  • ANA CAROLINA MORAIS APOLÔNIO
  • EDUARDO HENRIQUE SILVA DE SOUSA
  • Data: Feb 28, 2018


  • Show Abstract
  • The aim of this work is to synthesize complexes of the iron-cyclam system with the phthalate (ph), salicylate (sa) and oxalate (ox) ligands, to obtain the complexes [Fe(cyclam)ph]Cl (1), [Fe(cyclam)sa]PF6 (2) and [Fe(cyclam)ox]PF6 (3), respectively. The characterization of the complexes was performed using spectroscopic techniques (IV, Uv-vis) and electrochemical (CV and DPV). The IR spectra showed vibrational modes in the range of 3443-2878 cm-1, for the N-H group and C-H stretches of the cyclam macrocyclic ligand, as well as vibrational modes in the region of 1706-1550 cm-1 and 1375-1343 cm-1, corresponding to the nas(O-C-O) and ns(O-C-O), attributed to bidentate coordinated oxygenated binders. The electronic spectra of the complexes in aqueous medium presented intraligant transitions in more energetic regions, while the LMCT transitions were observed at higher wavelengths, observed at 325 nm (1), 527 nm (2) and 292 and 355 nm (3). And the cyclic voltammetry of the complexes exhibited a nearly reversible Fe3+/2+ redox pair, with E1/2 = 25.5 mV (1), 209 mV (2) and -41.9 mV (3). In addition, the complex (3) was characterized by Mössbauer spectroscopy, and also had its investigated photochemical and antibacterial activity. The mössbauer spectrum in 300K showed a doublet (D1) with d= 0.30 mm/s and ΔEQ = 0.40mm/s, typical of Fe3+ with high spin configuration. However, with the lowering of the temperature, it was observed the gradual reduction of the intensity of D1 and the appearance of a second doublet (D2), with d= 0.19 mm/s and ΔEQ = 1.73 mm/s to 12 K, typical Fe3+ low spin. Characterizing the existence of a temperature dependent spin state transition process. The photochemical reactivity evaluated by IR with exposure to white light evidenced the degradation of the oxalate ligand coordinated to the metal, being relevant in the synthesis of new complexes of the Fe-cyclam system and in the antibacterial activation. Through the photochemical reaction of the compound the binuclear [((cyclam)Fe)2(μ-SO4)](PF6)2.H2O was obtained, whose structure was identified by X-ray diffraction of monocrystal. The antibacterial activity of the complex (3) was evaluated against Pseudomonas aeruginosa (ATCC 9027), Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922). The best results were obtained for Pseudomonas, with minimum inhibitory concentration (MIC) of 293.5 μM. However, exposure of the compound to white or blue light for 90 min, potentiated the inhibitory activity of the complex by around 59% against Pseudomonas, reducing MIC values to 118.6 μM (white light) and 119.5 μM (blue light). When submitted to 240 min of exposure, the activity was potentiated in 79.5% (white light) and 77.4% (blue light). Therefore, the photochemical activity of the complex (3) represents a promising alternative in bacterial combat.

4
  • LEOMIR AIRES SILVA DE LIMA
  • NEW SPECTROSCOPIC AND ELECTROCHEMICAL METHODOLOGIES APPLYING MULTIVARIATE CLASSIFICATION IN BIOLOGICAL SYSTEMS

  • Advisor : KASSIO MICHELL GOMES DE LIMA
  • COMMITTEE MEMBERS :
  • KASSIO MICHELL GOMES DE LIMA
  • FABRICIO GAVA MENEZES
  • RENATA ANTONACI GAMA
  • EDVAN CIRINO DA SILVA
  • SHERLAN GUIMARÃES LEMOS
  • Data: Mar 16, 2018


  • Show Abstract
  • This thesis demonstrates the application of instrumental techniques such as: near and medium infrared spectroscopy, molecular fluorescence and differential pulse voltammetry, combined with multivariate classification and variable selection techniques applied to biological system such as tissue, fly larvae and blood plasma . In a first study, NIR spectroscopy was used to obtain healthy and critically defective rat skull spectra. Multivariate classification models were constructed, aiming at an alternative methodology to estimate the success rate of bone repair through low intensity laser and collagen treatments. The algorithms PCA-LDA, SPA-LDA and GA-LDA were applied as classification tools and their comparative performances. In general, the NIR spectra were able to classify the control group of the others showing efficiency in the evaluation of wound healing in rat cranial defect. In a second study, ATR-FTIR spectroscopy was used to obtain blood plasma spectra of healthy elderly patients with sarcopenia. Multivariate classification models were constructed, aiming at a diagnostic methodology for screening of sarcopenic elderly. The algorithms PCA-LDA, SPA-LDA and GA-LDA were applied as classification tools and their comparative performances. In general, the results obtained through the SPA-LDA and GA-LDA variable selection algorithm were the most satisfactory, since they could be related to functional groups belonging to different biomolecules and possible biomarkers. In a third study, differential pulse voltammetry and molecular fluorescence excitation / emission matrices were obtained for extracts of control fly larvae and containing the drug flunitrazepam. The performance of the classification algorithms with linear and quadratic discriminant and linear discriminant functions for voltammograms and the 2D-LDA algorithm compared to PARAFAC-LDA were evaluated for classification among the groups investigated. Hit rates above 90% were obtained for the control and flunitrazepam classes. The results suggest that spectroscopic and electrochemical methods added to the multivariate analysis are capable of undermining relevant information about the understanding of the biological dynamics of several organisms, as well as contributing to the public health system in the identification of sarcopenia in the elderly.

5
  • PAULO HENRIQUE SILVA SANTOS MOREIRA
  • CARBOXYMETHYL LIGNIN AS A MULTIFUNCTIONAL ADDITIVE FOR THE PETROLEUM INDUSTRY: an alternative for the use of lignocellulosic biomasses

  • Advisor : JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • COMMITTEE MEMBERS :
  • ERIKA PINTO MARINHO
  • FABÍOLA DIAS DA SILVA CURBELO
  • JÚLIO CÉZAR DE OLIVEIRA FREITAS
  • ROSANGELA DE CARVALHO BALABAN
  • ULISSES TARGINO BEZERRA
  • Data: Apr 27, 2018


  • Show Abstract
  • The thesis presents carboxymethyl lignin (CML) as a multifunctional additive for applications in the petroleum industry. The carboxymethylation reaction follows the classical reaction of Williamson ethers where an alkoxide (lignin alkali) is reacted with an alkyl halide (monochloroacetic acid) to form an ether. CML was evaluated as retardant additive for cement pastes and as a scale inhibitor additive. The studies on CML as a set retarder were performed with a lignin extracted from the sugarcane bagasse by the soda-anthraquinone method. The lignin derivative was added to the cement paste composition and tested in pressurized consistometry (API RP 10B) assays to determine the thickening time (setting time) of the tested pastes. The increase in the time of thickening of the cement pastes as a function of the addition of CML to the composition was observed. A second mechanism of action (besides the classic) for CML was proposed. Semi-empirical calculations were performed to simulate the ability of CML to form coordination complexes with Ca2+ ions fundamental to the cement set process. The proposed complex was entropically favorable in a spontaneous process with relation to Gibbs free energy. These observations about CML's ability to adsorb in the cement core and to complex Ca2+ ions motivated the study on scale inhibitor. For this work, the carboxymethylation reaction was applied to a lignin extracted from the wood by the Kraft method. CML was evaluated as a scale inhibitor in a synthetic system of produced water from oil field. Inhibition efficiency tests were performed by the dynamic method (dynamic capillary tube precipitation) according to the procedures of NACE 31105 and by the static method. The crystals formed by the static method were analyzed by scanning electron microscopy (SEM) and X-ray diffraction. It was observed that in the absence of CML the scale products were basically the polymorphs of CaCO3 with predominance of the polymorph aragonite with calcite in smaller proportion. In the presence of CML, the MEV images showed an inhibition of growth of aragonite and calcite rods as the major phase in the fouling products. XRD assays associated with Rietveld's refinement technique have confirmed that aragonite actually reduced its percentage in the inlay composition and the SEM images also show that crystal growth has been reduced by an order of magnitude. The results of the research show that the lignin carboxymethylation may be a technological alternative to add value to the lignocellulosic biomass residues and that its versatility can cover several sectors of the oil and gas industry.

6
  • FLAVIA FREITAS VIANA
  • MICROEMULSIONS AND NANOEMULSIONS WITH ALKALI-SURFACTANT-POLYMER APPLIED IN ADVANCED OIL RECOVERY

  • Advisor : TEREZA NEUMA DE CASTRO DANTAS
  • COMMITTEE MEMBERS :
  • DJALMA RIBEIRO DA SILVA
  • FABÍOLA DIAS DA SILVA CURBELO
  • MARCOS ALLYSON FELIPE RODRIGUES
  • RICARDO HENRIQUE DE LIMA LEITE
  • TEREZA NEUMA DE CASTRO DANTAS
  • Data: May 4, 2018


  • Show Abstract
  • The combination of polymer, surfactant and alkali in a same slug, known as alkali-surfactant-polymer method (ASP) presents favorable characteristics for use in advanced oil recovery (EOR). In this work, multi-component microemulsion and nanoemulsion systems with ASP were developed for application on reservoir rock wettability reversal and EOR. Pseudoternary diagrams in region rich of aqueous phase were obtained and some points were  selected for application. The sodium carbonate was selected as alkalinizing agent and subsequently 0.6% of three commercial polymers of polyacrylamide in aqueous phase were used to formulate new Microemulsion systems. With ASP MicroEmulsion points, by dilution method, systems were formulated nanoemulsions containing 1.5% of Na2CO3 and 0.06% of polymer. The microemulsions and nanoemulsions were characterized according to the average droplet diameter, maximum size and format of micelar aggregates, hydrogen ionic potential, surface tension, viscosity and rheological behavior through mathematical models, and finally applied on wettability reversal through contact angle and EOR through oil Simulator using sandstone rock Botucatu. The sizes of Microemulsion droplets are characteristic values, the maximum size of micelar aggregates was 4.2 nm and the formats of the micelles were Oblate ellipse type, ball and hollow sphere. PH confirmed an alkaline value (average pH equal to 10.0) and surface tension has been reduced, with values below 35.0 mN/m at 24° C ± 1. For microemulsions without polymer and the nanoemulsions rheological behavior was Newtonian-type, the other microemulsions rheological mathematical model of non-Newtonian fluids was appropriate, being the model of Ostwald of Waale, characteristic of fluids Polymeric. The viscosity of Microemulsion with polymers, with values of the cP 41 19, 24° C ± 1, were all larger than the average oil (29.3° API) present in the reservoir rock Botucatu, was 14.5 cP . All systems formulated left the wettable rock water, being efficient in the wettability reversal, favoring the  the oil production. The results proved the efficiency of recovery and displacement of Microemulsion  and nanoemulsions, once the total  oil  in place recovery were high, ranging from 65% to 97%.

7
  • ARTUR DE SANTANA OLIVEIRA
  • DESIGN OF NEW NANOCARRIERS FOR CONTROLLED DRUG DELIVERY OF OLANZAPINE AND CAMPTOTHECIN

  • Advisor : SIBELE BERENICE CASTELLA PERGHER
  • COMMITTEE MEMBERS :
  • SIBELE BERENICE CASTELLA PERGHER
  • NEDJA SUELY FERNANDES
  • FERNANDA NERVO RAFFIN
  • ANA CLÉCIA SANTOS DE ALCÂNTARA
  • PABLO BOTELLA ASUNCION
  • VERA R. LEOPOLDO CONSTANTINO
  • Data: May 9, 2018


  • Show Abstract
  • In recent years, related biomedical studies have been developing with a special emphasis on the controlled drug release from the development of nanostructured materials in exploration of improvements in drug administration. For the development of controlled release systems, we look for factors such as the type of drug, type of administration, resistance of the carrier material in aqueous media, biocompatibility and others. This work was carried out from the studies of the drugs Olanzapine and Camptothecin. Olanzapine (OLZ) is a drug that acts in the treatment of schizophrenia and presents low solubility in aqueous media making it difficult to treat the diseases. The controlled release system for OLZ proposes the incorporation of OLZ into an inorganic support based on montmorillonite (MMT) dispersed in a biopolymer mixture of Alginate (ALG) and Xanthan Gum (GX). After the synthesis of the proposed materials, hybrids and bionanocomposites were characterized by some techniques. The characterizations showed the intercalation of drug in the MMT by ion exchange process, as well as interaction with the biopolymers. The release test was able to show at different pHs that the proposed system shows a more controlled release for the drug studied, than when dissolved only the commercial tablet, indicating that the developed material can act as a controlled release system. For the study of Camptothecin, wide-range spectrum antitumor, the drug was incorporated in a 100% organic matrix through a covalent bonding to COF-5 (Covalent Organic Framework). So, one of the ligands used in the synthesis of COF-5, 1,4-benzenediboronic acid (BDBA), was subjected to nitration and reduction with H2 to provide a functionality with NH2 groups on the pore walls. An esterification with camptothecin and succinic acid was required for subsequent amidation to be obtained successfully. Sequential pore wall modification of covalent organic frameworks (e.g., COF-5) with nucleophyllic groups (e.g., amino) yields highly functionalized materials with outstanding resistance to hydrolytic digestion. Subsequent bonding of camptothecin reports the first case of a stable drug delivery system based on covalently conjugated COFs. The syn