Isotherm, kinetics and thermodynamic analysis of dye removal from aqueous solutions using chestnut shell

Abstract

In this study, the removal of crystal violet dyes from aqueous solutions using chestnut shell was investigated. For this purpose, the effects of parameters such as initial dye concentration, adsorbent dosage, contact time, pH and temperature on adsorption performance were investigated. According to the results obtained, the removal efficiency increased with increasing temperature and adsorbent dosage. It was observed that the removal efficiency decreased when the initial dye concentration increased. In the isotherm studies using equilibrium adsorption data, the best results were obtained in the Langmuir isotherm and the maximum dye adsorption capacity under optimized conditions was calculated as 48.78 mg/g. Kinetic studies were carried out using pseudo-first and pseudo-second-order kinetic models and it was determined that the pseudo-second-order kinetic model was the most appropriate (R2>0.99). Thermodynamic parameters (?Go, ?Ho, ?So) showed that the adsorption process was feasible, spontaneous and endothermic. In addition, FTIR analyzes were performed before and after adsorption. These results showed that chestnut shell can be used as an alternative and low-cost material for the removal of crystal violet from aqueous solutions. © 2025 Elsevier B.V., All rights reserved.