Banca de QUALIFICAÇÃO: JOICY RIBEIRO DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : JOICY RIBEIRO DOS SANTOS
DATE: 31/01/2022
TIME: 09:00
LOCAL: Google meet
TITLE:

Potential use of Mandacaru (Cereus jamacaru) as a natural bioadsorbent agent for heavy metal water decontamination

KEY WORDS:

Heavy metal remotion, Cereus jamacaru, bioadsorbent, chemometric, factorial design, ICPOES.

PAGES: 70
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Análise de Traços e Química Ambiental
SUMMARY:

The interest for sustainable solutions for water decontamination is a relevant issue for the future, once the human beings and their industrial processes have been polluted the environment and consequently destroying the natural life cycle. In this context, studying the natural products in order to develop new remediation methodologies that are low cost, efficient, easy to apply and that brings fast results is a way to mitigate these environmental damages. Therefore, this work to characterize and apply the species Cereus jamacaru, popularly known as Mandacaru, as a bioadsorbent agent for heavy metals in water synthetically contaminated by Cu²⁺ and Pb²⁺ ions. The Mandacaru was chosen because it is a Brazilian native species and well distributed throughout the northeast region. The plant was collected in Lajes Pintadas / RN and was biologically characterized in the UFRN herbarium (26848 registration number). The rods were divided in three regions pup without cover (PSC), pup with cover (PCC) and core (M). The aqueous extract (0.4 g mL^-1) of each one of regions was characterized using standard methodology considering soluble proteins, full carbs and phenolics compounds.  Furthermore, a Fourier Transform Infrared Spectrometry (FTIR) characterization before and after the bioadsorption process provided evidence of interactions of the functional groups -OH, -CO and C=O with metallic ions. A complete factorial design experiment was developed to investigate the variables that affect the bioadsorption process considering as variables the pH solution, contact time, ionic strength and cactus region. The experimental responses obtained by Inductively Coupled Plasma Atomic Emission Spectrometry (ICPOES) was employed in the model of maximum metallic ions removal desirability. The PCC region, in a pH 5.0 solution, without influence of ionic strength and contact time of 4h was observed as the best condition. A remediation simulation was applied to a control sample and to real river and seawater by adding 500 ppb of both metals to the solution. In the control sample, removal was 64.0% for Cu²⁺ and the final concentration of Pb²⁺ ion was lower than the detection limit of the technique (LD < 0.006 ppb). For river water, the removal was 59.2 and 97.3% for Cu²⁺ and Pb²⁺, respectively. In the seawater sample, the behavior of the signals by ICPOES showed a matrix effect, but it was still possible to observe a decrease in the concentration of ions with the contact time simulation with the cactus. The experimental values obtained for the control sample and for the river water agreed with the values predicted by the chemometric model, which were 54.1 and 96.1% for Cu²⁺ and Pb²⁺ ions, respectively. Finally, we can conclude that the species investigated in this work has shown a potential ability to remediate contaminated water with these metallic ions, opening new possibilities for applications of this bioadsorbent material in real scenarios of environmental contamination.

BANKING MEMBERS:
Interna - 1805556 - LUCIENE DA SILVA SANTOS
Presidente - 2413537 - POLLYANA SOUZA CASTRO
Externo à Instituição - RAONI BATISTA DOS ANJOS