Adsorption Studies of Activated Carbon Prepared from Industrial Waste Lignin for the Removal of Malachite Green

Abstract

Activated carbon has been prepared from industrial waste lignin (IWL) using ZnCl2 as an activating agent. This prepared activated carbon was utilized for adsorption of the malachite green (MG) dye. Here an endeavor has been made to study the applicability of IWL as potential dye adsorbent for the removal of MG from aqueous solution. The systematic optimization involved the study of factors such as effect of adsorbent doses, pH, and contact time. Langmuir, Freundlich, and B.E.T. isotherms were applied to the data obtained at equilibrium. A maximum adsorption capacity of 111.11 mg/g of MG was achieved by activated carbon obtained from IWL using ZnCl2. The adsorption isotherm data was found to fit well into Langmuir and B.E.T. isotherm models with R values 0.99. The kinetic data obtained at various concentrations was studied to determine the constant rate of adsorption using Langmuir adsorption kinetics model. It shows that the rate of adsorption is very high as compared to the rate of desorption which indicates MG dye is irreversibly adsorbed on the adsorbent.