1996 Volume 45 Issue 11 Pages 975-986
A concept of "Surface Imprinting" has been proposed by the present authors. First, we prepared a metal ion-imprinted microsphere on the basis of the concept. The imprinted microspheres as a new metal ion-selective adsorbent were synthesized by seeded emulsion polymerization of divinylbenzene, styrene, butyl acrylate, and methacrylic acid. The imprinted structure was introduced on the carboxylated microsphere by Surface-Imprinting, in which the carboxyl groups were reorganized through complexation with metal ions on the surface, and then fixed by crosslinking polymerization in their specific orientation. Cu(II), Ni(II), and Co(II)-imprinted microspheres were obtained as submicron particles with average diameters of 0.550.60 μm.They were immediately used as a metal ion-selective adsorbent without any further treatment, such as grinding or sieving. The adsorption behaviors of metal ions {Cu(II), Ni(II), and Co(II)} were examined, and the imprinted effects were verified on these imprinted microspheres. The imprinted microspheres adsorbed the corresponding guest ion more effectively than did unimprinted ones. Furthermore, a Cu(II)-imprinted microsphere was studied in detail in order to obtain information about the origin of the imprinting effect. Unimprinted and Cu(II)-imprinted microspheres were prepared under several pH (4.0, 5.0, 5.6, or 6.0) conditions in the imprinting step. The obtained microspheres were characterized for particle form, size-distribution pattern, average diameter, Cu(II)adsorption behavior, and so on. Spectroscopic studies were also performed on Cu(II)-loaded microspheres.The collected data indicate that the origin of the imprinting effect on a Cu(II)-imprinted microsphere is an interaction between Cu(II)and the carboxylate group at the aqueous-organic interface, supporting the concept of Surface Imprinting.
