Banca de QUALIFICAÇÃO: RENNAN FÉLIX DA SILVA BARBOSA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RENNAN FÉLIX DA SILVA BARBOSA
DATA : 04/04/2025
HORA: 09:00
LOCAL: On-line
TÍTULO:

Development of chitosan hydrogels containing modified cellulose nanostructures for removal and recovery of metals in contaminated water

PÁGINAS: 177
RESUMO:

The presence of potentially toxic elements in water, especially metal ions, has been a major environmental concern due to their effects on the health of living beings. This study aimed to develop sustainable alternatives using chitosan hydrogels containing modified cellulose nanostructures to remove copper, nickel, cadmium, and chromium ions. A study was carried out to develop the hydrogel using experimental planning to define the ideal concentration of chitosan and glutaraldehyde for the hydrogel formulation used. Next, eucalyptus waste was used as a cellulose source, which underwent combined mechanical treatment and isolation methods to obtain cellulose nanostructures, which were then modified using three different routes. The nanostructures were evaluated and incorporated during the formulation of chitosan hydrogels to get a functional material with optimized performance. The experimental design allowed the impact of the concentration of chitosan and glutaraldehyde on the properties of water absorption and adsorption of metal ions to be evaluated using response surfaces, with the formulation with 2% chitosan and 1% glutaraldehyde standing out. The combined isolation method effectively obtained cellulose nanostructures, which were then modified, especially the routes using succinic anhydride and EDTA dianhydride, which showed direct evidence of modification by infrared and magnetic resonance analysis. The modifications promoted significant increases in the removal of metal ions, demonstrating a direct influence of pH on sorption and reaching qmax of 1.75, 2.22, 1.81, and 1.60 mmol g-1 for copper, nickel, cadmium, and chromium, respectively, according to the Langmuir isotherm, which showed a better fit to the data and indicated a preferential chemisorption process. The hydrogels showed different optimum levels of incorporation, depending on the type of nanostructure, showing water absorptions of around 450% and significant increases in sorption capacity due to the incorporation of the modified nanostructures, illustrating their potential for water decontamination.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1760410 - JEVERSON TEODORO ARANTES JUNIOR
Membro Titular - Examinador(a) Externo à Instituição - MELISSA GURGEL ADEODATO VIEIRA - UNICAMP
Membro Titular - Examinador(a) Externo à Instituição - SIMONE DE FÁTIMA MEDEIROS SAMPAIO - USP
Membro Titular - Examinador(a) Externo à Instituição - ALEXANDRE TADEU PAULINO - UDESC
Membro Suplente - Examinador(a) Interno ao Programa - 2605463 - JOSE ANTONIO SOUZA
Membro Suplente - Examinador(a) Interno ao Programa - 1309493 - PEDRO ALVES DA SILVA AUTRETO
Membro Suplente - Examinador(a) Externo à Instituição - ANA MARIA COULON GRISA - UCS
Membro Suplente - Examinador(a) Externo à Instituição - MARA ZENI ANDRADE - UCS