Banca de DEFESA: CAMILA COSTA PETROLEO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : CAMILA COSTA PETROLEO
DATE: 25/07/2023
TIME: 14:00
LOCAL: https://conferenciaweb.rnp.br/webconf/wagner-27
TITLE:

Identification and quantification of acid groups present on the surface of carbons

PAGES: 83
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Química de Interfaces
SUMMARY:

The surface chemistry of coals is largely determined by the number and nature of surface functional groups. Although activated carbons are widely used as adsorbents and catalysts, their high production cost has directed interest towards so-called biochars, a low-cost alternative with comparable or even superior performance. A variety of biomass sources can be used, including agricultural residues or agro-industrial by-products such as rice husks, sugarcane bagasse, coffee beans, glycerin, and sugars. The surface chemistry of coals is largely determined by the number and nature of surface functional groups. Several functionalities can be inserted on the surface of these carbons, with emphasis on the acidic groups, responsible for a significant improvement in the adsorptive and catalytic properties of the solids. Thus, several procedures and studies have been carried out in the research group to optimize the insertion of acid groups, both Brønsted and Lewis, on the surface of coals. Once inserted, the acid groups need to be assessed, to differentiate between Lewis and Brønsted acids (considering sulfonic, carboxylic, phenolic, and lactones), as well as their acid strength, thermal stability, and quantification. Several techniques have been used, such as Boehm titration, potentiometric titration, infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). Each technique has its specific application, and the biggest problem associated with these measurements is the absolute quantification of acidic or basic sites, often being limited to relative comparisons between samples. Thus, the objective of this work was, to investigate the titration technique and propose a chromatographic methodology for a qualitative and quantitative analysis of Brønsted and Lewis acid sites on coal surfaces.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 1601156 - WAGNER ALVES CARVALHO
Membro Titular - Examinador(a) Interno ao Programa - 1933328 - HELOISA FRANCA MALTEZ
Membro Titular - Examinador(a) Externo à Instituição - THIAGO DE CARVALHO CIPRIANO - CTI
Membro Suplente - Examinador(a) Interno ao Programa - 2145401 - DIOGO LIBRANDI DA ROCHA
Membro Suplente - Examinador(a) Externo à Instituição - ANTÔNIO CARLOS FERREIRA BATISTA