Abstract:

Micron-sized thiocyanate anion-imprinted microspheres(IIPMs) were prepared successfully with inverse suspension polymerization method. In the inverse suspension polymerization system, cyclohexane was used as dispersion medium and Span-60 was used as dispersant in the oil phase, cationic monomer of acryloxyethyltrimethyl ammonium chloride(DAC), the crosslinker N, N'-methylene bisacrylamide(MBA) and the template SCN^- anion were dissolved in aqueous phase. The crosslinking copolymerization of DAC in water-in-oil droplets was carried out and SCN^- IIPMs with diameter of about 200 μm were obtained. The ion recognition selectivity and binding property were investigated with monovalent anions, NO₃^- and I^-, as the references. In water-in-oil droplets, since cationic monomer DAC associates with SCN^- anion by strong electrostatic interaction, SCN^- anions are imprinted while DAC produces crosslinking polymer. The prepared IIPMs possess strong binding ability(3.3 mmol/g(192 mg/g)) and selectivity. The IIPMs can selectively recognize and bind SCN^- anion from a mixture with NO₃^- and I^- ions. The coefficients of the selectivity of IIPMs are 3.24 and 6.78, respectively. The IIPMs also exhibit excellent reusability.

Key words: reversed phase suspension, imprinted microspheres, electrostatic interaction, ion imprinting, ion recognition