Study On The Metal Ion Imprinted Polymeric Microspheres

Molecular imprinted polymers(MIPs), as molecular recognition materials with high selectivity to imprinting molecules, have extensive potential application in separation, purification, enzyme mimic, biomimic sensors, membrane separation and other fields.This paper aimed to study the preparion technique of metal ion imprinted polymer in aqueous system, the surface morphology of polymer obtained and their selective properties to metal ions.In this paper, Cu2+ imprinted polymer microspheres were prepared by reverse-emulsion suspension polymerization. The methacrylic acid (MAA), TRIM and SDBS were used as functional monomer, polymeric matrix and dispersant respectively. The process affecting the polymer morphology, such as the kind and amount of dispersant, the amount of functional monomer, the Cu2+ concentration and the composition of external aqueous phase, were investigated in detail. At the same time , the selective adsorption to Cu2+ and Ni2+, including the dynamics and thermodynamics, was performed. The results indicated that the polymer obtained exhibited good selectivity to Cu2+ and Ni2+ and the separation factor up to 1.54.Cu2+ and Ni2+ imprinted polymers were prepared with the optimal recipe obtained by previous studies and 2-acrylanido-2-methyl-propanesulfonic acid(AMPs) as functional monomer. It was showed that the particle size and swelling rate of imprinted polymers increased with the increase of functional monomer. The adsorption capacity to imprinted metal ion enhanced with the increase of mol ratio between functional monomer and imprinted metal ions. However the relative separation factor ( firstly increased and then decreased.Moreover, in order to avoid the bad effect of other metal ions on the Cu2+ imprinted polymer, the polymers were performed by inverse emulsion suspension polymerization and PVA as dispersant. The process of preparing was studied and selective adsorptions were carried lastly, the suspension polymerization method was applied to manufacture Ni2+ imprinted polymer and MAA as functional monomer. Those factors affected the polymer morphology, for instance the amount of functional monomer, the added order of AIBN, the ratio of oil and water, the amount of toluene, were investigated detailed. A further research on the selectivity of polymers to the imprinted metal ion and competitive ion was performed. The results showed the resulting polymer appeared regular sphericity and existed good recognition property to imprinted ion in mixture of imprinted ion and competitive ion.