Comparative Study Of The Biosorption Of Cadmium(Ⅱ), Chromium(Ⅲ), And Lead(Ⅱ) By Olive Stone

摘要

This research focuses on potential of using olive stone as a low-cost biosorbent, for cadmium, chromium, and lead removal from aqueous solutions in a batch system as a function of pH, contact time, and temperature. Experimental data were tested in terms of biosorption kinetics using pseudo-second-order kinetic model. The results showed that the biosorption processes of the three metal ions followed well pseudo-second-order kinetics at 25, 40, and 60℃ and for a metal initial concentration of 10 mg/L. The activation energy of biosorption (E) was determined as 7.09 kJ/ mol for Cd(Ⅱ), 12.39 kJ/mol for Cr(Ⅲ), and 10.29 kJ/ mol for Pb(Ⅱ) indicating that the biosorption of these metal ions was taken place mainly by physical interactions. The equilibrium biosorption was also studied at these temperatures applying Sips isotherm model. Using the Sips constant, b, the thermodynamic parameters were calculated. The values of these parameters showed that the biosorption of Cd(Ⅱ), Cr(Ⅲ), and Pb(Ⅱ) ions by olive stone was feasible and spontaneous and reflected the endothermic nature of the process for the removal of Cr(Ⅲ) and Pb(Ⅱ) except Cd(Ⅱ).