Adsorption of chromium(VI) from aqueous solution by activated carbon derived from olive bagasse and applicability of different adsorption models

In this study, activated carbon was prepared from olive bagasse by physical activation of steam. The pore properties including the BET surface area, pore volume, pore size distribution and average pore diameter were characterized. BET surface area of the activated carbon was determined as 718 m(2)/g. The removal of Cr(VI) from aqueous solutions by adsorption has been studied. The effects of pH. contact time and temperature on adsorption of Cr(VI) were investigated. The maximum adsorption yield was obtained at the initial pH of 2. The adsorption kinetics shows that pseudo-second order rate expression fitted the adsorption kinetics. Equilibrium isotherms were measured experimentally. Results were analyzed by the Langmuir, Freundlich, Dubinin-Redushkevich, Temkin and Frumkin equations Using linearized correlation coefficient at different temperatures. The characteristics parameters for each isotherm have been determined. Models and isotherm constants were evaluated depending on temperature. Langmuir equation was found to fit the equilibrium data for Cr(VI) adsorption. (C) 2008 Elsevier B.V. All rights reserved.