Sorption kinetic analysis for the removal of cadmium ions from effluents using bone char

The adsorption of cadmium ions onto bone char has been studied using a batch adsorber. The experimental data was analyzed using four sorption kinetic models-the pseudo-first order, the Ritchie second order, the modified second order and the Elovich equations-to determine the best-fit equation for the sorption of metal ions onto bone char. The best-fit equation was identified using the sum of the errors squared ( SSE). Finally, equilibrium studies were used to evaluate the sorption capacity of bone char for cadmium ions and experimental results showed this to be 0.57 mmol g −1 at an equilibrium solution concentration of 3.0 mmol dm −3. Since the sorption capacity is relatively high, bone char can be considered as a suitable sorbent for the adsorption of cadmium in wastewater treatment systems.