Kinetic and equilibrium study of Alizarin Red S removal by activated carbon

Abstract

Activated carbon has been applied for the adsorption of Alizarin Red S (ARS) from the waste water in a batch method to obtain high removal percentage. The influence of variables such as pH, temperature, ARS concentration, mass and size of adsorbent, and contact time on ARS removal percentage was investigated. Different kinetics, thermodynamics, and isotherm models were applied for fitting the experimental data. The adsorption process follows a pseudo second-order kinetic model with R 2 of 0.98 and Freundlich, Tempkin, and Dubinin-Radushkevich isotherm models with high determination coefficients (R 2) of 0.91, 0.98, and 0.98, respectively. High enthalpy (positive value), Gibbs free energy (negative value), and high entropy values shows the feasibility and the endothermic spontaneous nature of the removal process.