A novel sorbent, bio-formulation(BF), was prepared and employed for the adsorption of cadmium(Cd) ion from aqueous
system. The process of adsorption follows the pseudo second-order kinetic equation and the adsorption behavior is fitted with a
Freundlich isotherm. The removal rate of Cd is slightly dependent on the initial pH value over a wide range of 4-1 1. The addition of
Zn2’ and CU” ions hardly affects the Cd adsorption, whereas the coexisting Pb2+ ion greatly interferes with the adsorption. The
adsorption mechanism is supposed as a cation-exchange process between Cd” and calcium and Mg2+ present on the surface of BF,
and somewhat as adsorption in a hydrolyzed form. The adsorbed Cd ions are desorbed effectively by a 0.1 mol/L HCI solution.