Development of a new ion-imprinted polymer (IIP) with Cd2+ ions based on divinylbenzene copolymers containing amidoxime groups

Abstract

In this study, we synthesized a new ion-imprinted polymer (IIP) based on introduction of amidoxime groups in acrylonitrile, complexation with Cd2+ ions and polymerization with styrene and divinylbenzene by aqueous suspension polymerization. A non-imprinting polymer (NIP) was also synthesized. The adsorption tests of Cd2+ by IIP were performed by varying the pH, Cd2+ ion concentrations and contact time between the ions and the IIP. Kinetic models and adsorption isotherms were applied to evaluate the behavior of the IIP. The optimum conditions for Cd2+ adsorption by IIP were pH 6.0 and equilibrium time of 12 min. The increase in initial concentration of the Cd2+ ions resulted in an increased sorption capacity, qe. The Elovich and Freundlich were the most appropriate models to describe the sorption equilibrium and the sorption mechanism, respectively. Selectivity studies were conducted in the presence of Zn2+, Pb2+, Cu2+ and Ni2+. The selectivity results showed that the NIP was not selective for Cd2+ ions and the IIP was selective for Cd2+ ions in relation to ions of Zn2+, Cu2+ and Ni2+, but not in relation to Pb2+ ions.