Adsorption of cadmium and lead in wastewater by four kinds of biomass xanthates.

This study determined the adsorption of Cd and Pb (100 mg·L of each) in simulated wastewater by biomass xanthates made from starch, chitosan, wheat stalk and corn stalk. The results showed that the adsorption efficiency of Pb and Cd ions followed the order: corn stalk xanthate > wheat stalk xanthate ≥ chitosan xanthate > starch xanthate. The results of kinetic modeling showed that the adsorption process was characterized by physical-chemical adsorption, and that a second-order kinetics equation described the adsorption process well. The optimum conditions for the adsorption of Cd and Pb by corn stalk xanthate were: adsorption time 2 hours, temperature 20-25 °C, and pH 6-8. The results serve as a reference for treating wastewater containing Cd and Pb2.