Adsorption of Metal Ions to Surface-Template Resins Prepared with Amphiphilic Styrene Monomers Bearing Amino Carboxylic Acid

Monomer-type functional surfactants, 2-(p-vinylbenzylamino)alkanoic acid (RnNAc) and N,N-dialkyl derivatives (RRnNAc), have been used as both a ligand and an emulsifier for the preparation of surface-template resins. The surfactants adsorbed at the toluene–water interface and emulsified divinylbenzene–styrene in a Cu2+ or Zn2+ solution. Emulsion polymerization using a K2S2O8 initiator (80 °C) or by irradiation with γ-rays gave fine particles of 200—800 nm in diameter. Metal-imprinted resins prepared with RnNAc and RRnNAc showed a high adsorptive capacity for the metal ion (surface-template effect). Cu-imprinted resins prepared with R8NAc were 2.69-times as effective for Cu2+ in competitive sorption from a Cu2+–Zn2+ mixture and Zn-imprinted resins were 1.84-times as effective for Zn2+, compared with unimprinted resins. Because of the great emulsifying power, metal-imprinted resins prepared with R8NAc showed the most metal-selective adsorption and the largest capacity among resins prepared with RnNAc and RRnNAc.