Uso de carvão ativado de babaçu na adsorção do corante fast green em efluentes sintéticos

Abstract

The constant increase in the pollution of rivers and lakes by industrial waste containing synthetic dyes has driven the search for eco-friendly and affordable solutions to address these pollutants. In this context, this research aimed to evaluate the efficiency of activated carbon produced from the shell of the babaçu coconut (Attalea speciosa) in the adsorption of the Fast Green dye, an anionic dye widely used in the textile and food industries. The activated carbon was obtained through physical activation with CO₂ and characterized in terms of pore structure, surface area, and functional groups. Batch adsorption experiments were carried out by varying the initial dye concentration, contact time, and adsorbent mass. The data obtained were analyzed using kinetic and isotherm models, with emphasis on the Langmuir and Freundlich models. The results indicated that babaçu-based activated carbon exhibited a high adsorption capacity, reaching up to 93.41% removal of the Fast Green dye under the best experimental conditions, corresponding to acidic pH, prolonged contact time, and greater adsorbent mass. The adsorption kinetics predominantly followed the pseudosecond-order model, while the Langmuir isotherm provided the best fit to the data, suggesting monolayer adsorption on a homogeneous surface. The pH analysis showed a significant influence on removal efficiency, with better performance under slightly acidic conditions. Based on these results, babassu activated carbon represents a promising, low-cost, and environmentally sustainable alternative for the treatment of effluents containing synthetic dyes, contributing to the reuse of agro-industrial residues and to the reduction of environmental impacts caused by water pollution.