Template-dependent selectivity in metal adsorption on phosphoric diester-carrying resins prepared by surface template polymerization technique

The surface templated resins for three different metal ions such as Cu2+, Zn2+ or Cd2+ as the template guest were prepared by emulsion polymerization using oleyl phenyl hydrogenphosphate as a host surfactant, sodium dodecyl sulfate (SDS) as a co-surfactant and divinylbenzene as a resin matrix-forming monomer. The Cu2+-imprinted resin adsorbed Cu2+ much more effectively than did the nonimprinted, the Zn2+- and Cd2+-imprinted ones. On the other hand, the Cd2+-imprinted resin showed a more highly effective binding to Cd2+ than those of the Cu2+-imprinted, Zn2+-imprinted, and nonimprinted resins. In fact, the Cu2+-imprinted resin did not adsorb any significant amount of Cd2+. The selective feature of the surface templated resins to the target ion was thus successfully demonstrated. The template-dependent selectivity should be ascribed to a favorable placement of the surface-anchored metallophilic groups for multidentate coordination to the specific metal ion.