Banca de QUALIFICAÇÃO: ELAINE CRISTINA DE SOUZA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ELAINE CRISTINA DE SOUZA
DATE: 18/11/2024
TIME: 13:00
LOCAL: videoconferência
TITLE:

OPTIMIZATION OF CARBOXYMETHYLCELLULOSE SYNTHESIS FROM RESIDUAL BIOMASS OF PINEAPPLE CROWN AND MANGO SEED VIA EXPERIMENTAL DESIGN

KEY WORDS:

Biorefinery; Residual biomass; Physicochemical treatment; Cellulose; Carboxymethylcellulose; Experimental design

PAGES: 82
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Química dos Produtos Naturais
SUMMARY:

Lignocellulosic biomass from agro-industrial residues has stood out in research on its reuse and the conversion of its components, mainly cellulose, for the biorefinery sector. Among the high value-added polymers from cellulose, carboxymethylcellulose (CMC) stands out with applications in several branches of industry, especially due to its viscosifying property when present in aqueous solution. This work presents contributions to t he biorefinery industry through the use of mango (MA) and pineapple (AB) residues, aiming at the production of high reactivity celluloses for conversion into CMC with high mass yield and water solubility, in a more environmentally friendly process based on the principles of Green Chemistry. The ABCel and MACel celluloses were extracted through the combined acid/peroxide-alkaline (APA) treatment, and later converted into CMC through the heterogeneous etherification process under different conditions, selected by a D-Optimal experimental design of 28 experiments, where the following factors were varied: Activation Time (TA), Reaction Time (RT), NaOH Concentration (NaOH%), Mass of monochloroacetic acid ( Ac. HAcCl) and Cellulose (ABCel or MACel). Analytical techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG/DTG) and X-ray diffractometry (XRD) were used to characterize the materials studied in this research, in order to evaluate the efficiency of the treatments and the reactivity of the pulps produced. The characterizations proved the efficient extraction of high-purity holocelluloses, as well as their successful carboxymethylation, especially due to the appearance of the characteristic CMC bands in the FTIR spectra. Models for evaluating the Mass Yield and Solubility responses were constructed through analysis of variance (ANOVA) with high precision (F = 36.36, p-value< 0.0001, R2 = 0.9655); in addition, optimization via response surface methodology (RSM) demonstrated that it is possible to generate products with good water solubility and significant yields (up to 244% m/m) from 2:15h of car boxymethylation, with the concentrations of NaOH and monochloroacetic acid, as well as the type of cellulose, being the most significant factors in the variation of responses. These results reaffirm the potential of using agro-industrial waste as a sustainable raw material for the production of CMC.

COMMITTEE MEMBERS:
Presidente - 1805556 - LUCIENE DA SILVA SANTOS
Externo à Instituição - CARLOS AUGUSTO CABRAL KRAMER - IFRN
Externa à Instituição - HELOISE OLIVEIRA MEDEIROS DE ARAUJO MOURA - UFRN
Externa à Instituição - LEILA MARIA AGUILERA CAMPOS - UNIFACS