Banca de QUALIFICAÇÃO: LUCAS ANTONIO DA SILVA DE JESUS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LUCAS ANTONIO DA SILVA DE JESUS
DATE: 19/12/2024
TIME: 13:00
LOCAL: MODO REMOTO
TITLE:

Application of biomass derived reduced graphene oxide as an adsorbent for different industrial effluents

KEY WORDS:

Adsorption; Graphene; Phenol; Dye; Removal, Biomass.

PAGES: 90
BIG AREA: Engenharias
AREA: Engenharia Química
SUBÁREA: Processos Industriais de Engenharia Química
SPECIALTY: Processos Orgânicos
SUMMARY:

Graphene consists of a single layer of carbon atoms arranged in a two-dimensional hexagonal structure, while reduced graphene oxide (rGO) is a modified form of graphene. Due to these unique characteristics, including its high surface area, adsorption capacity and functional groups that facilitate the adsorption of different pollutants present in industrial effluents, such as heavy metals, dyes and organic compounds, rGO is a promising material as an adsorbent. Recently, other carbon precursors have been investigated for alternative sources of graphene synthesis and one of them is biomass. The biomass-derived rGO used was characterized by HRTEM, XRD, Raman, FTIR, BET and Zeta potential. Therefore, this study was divided into three stages: In the first stage (I), the behavior of this rGO as an adsorbent to remove phenol from water was demonstrated. In this first study, 99% removal efficiency and a maximum absorption capacity (Qmax) of 240 mg/g were obtained, using 10 mg of rGO at an initial phenol concentration of 200 mg/L in 120 min, with pH 8.0 and temperature of 30ºC, these values are higher than those found in the literature. In the second stage (II), it was demonstrated how this rGO behaves in the adsorption of Methylene Blue (AM), which is a cationic dye. In this second stage of the study, 99% removal of AM was obtained with 50 mg of rGO at a dye concentration of 80 mg/L in 130 min, with pH 3.0 and temperature of 30ºC. The maximum absorption capacity (Qmax) value of 495.7 mg/g was obtained, which is higher than the values found in the literature. In the third stage (III), the adsorbent was applied to remove remaining dyes from a synthetic effluent obtained from a trichrome of disperse dyes. In this third stage, a removal of 98% was obtained using 0.3 g of rGO in 120 min. In the first three stages of this study, the Freundlich isotherm was the most appropriate, with an R2 value of 0.99 for both models, demonstrating that the adsorption occurs in multilayers on a heterogeneous surface. The kinetic study of the three stages demonstrated that the pseudo-second-order model is the most appropriate to describe the behavior of both, with an R2 value of 0.99. In the thermodynamic study, both stages showed positive enthalpy values (∆H°) confirming the endothermic nature of the reaction, with decreasing Gibbs free energy values (∆G°) indicating that higher temperatures have better removal efficiency and positive entropy values (∆S°) indicate that solid/liquid randomness occurs in the adsorption process.

COMMITTEE MEMBERS:
Presidente - 2941160 - JOSE HERIBERTO OLIVEIRA DO NASCIMENTO
Interno - 1584174 - DOMINGOS FABIANO DE SANTANA SOUZA
Externa ao Programa - 3919045 - JULIANA DELGADO TINOCO - UFRNExterno ao Programa - ***.778.283-** - RAFAEL BARBOSA RIOS - UFERSA