Remoção de corante Vermelho Congo de soluções aquosas utilizando cinzas de queima de bagaço de cana

Abstract

The discharge of industrial effluents containing synthetic dyes represents an important environmental problem due to their toxicity, persistence, and negative impacts on aquatic ecosystems. Congo Red dye, widely used in different industrial sectors, stands out for its resistance to removal by conventional treatment methods, reinforcing the need for efficient and sustainable alternatives for wastewater treatment. In this study, the potential of sugarcane bagasse ash, in its raw and chemically treated forms, as a biosorbent for the removal of Congo Red dye from aqueous solutions. The ash samples were characterized for their physical and chemical properties and applied in batch adsorption experiments, varying parameters such as contact time and initial dye concentration. The results showed that chemical treatment with NaOH significantly increased the adsorption capacity due to the greater exposure of active functional groups and the increase in specific surface area. The adsorption kinetics were best fitted by the pseudo-second-order model, suggesting that the process is mainly controlled by chemical interactions between the adsorbate and the biosorbent surface. The equilibrium data were better described by the Langmuir model, indicating monolayer adsorption. The maximum dye removal efficiency reached values above 80% under optimized conditions, demonstrating the potential of sugarcane bagasse ash as an alternative and economically viable material for textile effluent treatment.