Adsorção de corante vermelho do congo empregando carvão ativado de casca de arroz

Abstract

The consumption pattern of contemporary society has created challenges in seeking solutions to mitigate the inherent environmental impacts. Among these impacts are the contamination of water bodies by organic pollutants, such as dyes. In this way, several alternatives for wastewater treatment are sought, such as adsorption. For dyes, the adsorption technology has been considered promising due to its high efficiency, low cost and simplicity of operation. Thus, the present work aims to investigate the use of activated charcoal from rice husk for the treatment of Congo red dye, through studies of the thermodynamic balance of the system and the adsorption kinetics. The equilibrium experiments were conducted at different initial concentrations (25, 50, 100 and 150 mg L-1) and temperatures (25, 35 and 45 ° C). In the kinetic experiments, temperatures of 25, 35 and 45 ºC and initial concentrations of 50, 100 and 150 mg L-1 were used. In order to describe the adsorption isotherms, an integrated adjustment strategy for data from different temperatures was adopted, using the appropriate thermodynamic concepts. From the calculation of the corrected Akaike information criterion (AICc), the Langmuir model (AICc = 86.3) was determined to be the most appropriate to describe the adsorption balance. Thermodynamic parameters point to the phenomenon of physical adsorption in monolayer, with maximum adsorption capacity close to 160 mg g-1. For the study of adsorption kinetics, the mathematical models of Pseudo-First Order (PFO) and PseudoSecond Order (PSO) were tested, each employing different adjustment strategies to minimize the number of parameters. The most appropriate model was the PSO with coupling of the Langmuir isotherm model determined in the study (AICc = 127.4). In this way, the results obtained in this work contribute to the expansion of knowledge about the Congo red adsorption process using activated charcoal from rice biomass of rice husk and rational design of operation for the treatment of such effluent.