Adsorption kinetic models of heavy metal ions on granular activated carbon

Abstract

Adsorption is considered as one of the most effective and cost efficient methods in water effluents purification. Frequently used adsorbent for heavy metals removal is activated carbon. The adsorption of lead ions from wastewater model solutions on activated carbon has been studied by a batch adsorber. Experiments were performed at constant temperature, while the concentration of lead ions in the solutions has been varied. Using the MatLab software the parameters for the Langmuir and Freundlich adsorption isotherms were determined. The experimental data obeys the Langmuir isotherm, and the maximum sorption capacity determined was 17.09 mg g-1. The impact of the quantity of activated carbon and the initial concentration of lead ion on adsorption kinetics has been studied. The kinetics models for the first, pseudo-first, second and pseudo-second-order reaction were fitted to the experimentally obtained data by MatLab software. Data obtained by the kinetics study of Pb2+ adsorption on activated carbon, might be useful in the selection of the most probable mechanism of the adsorption process. It has been shown that the pseudo-second-order model explains the experimental data the best.