基于离子交换和表面引发接枝聚合制备阴离子表面印迹材料及其识别特性研究

建立了一种新的离子表面印迹(IIP)方法. 使用偶联剂γ-氨丙基三甲氧基硅烷(AMPS)对微米级硅胶微粒进行表面改性, 制得表面含有氨基的改性硅胶AMPS-SiO₂. 凭借离子交换作用, 阳离子单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)结合在模板离子磷酸根周围; 改性硅胶AMPS-SiO₂表面的氨基与溶液中的过硫酸盐构成氧化还原引发体系, 使DMC及交联剂N,N'-亚甲基双丙烯酰胺(MBA)在硅胶微粒表面发生接枝交联聚合, 从而实现了磷酸根离子的表面印迹, 制得了阴离子表面印迹材料IIP-PDMC/SiO₂. 采用静态与动态两种方法, 考察研究了IIP-PDMC/SiO₂对PO₄^3-离子的识别特性与结合性能. 研究结果表明, 离子表面印迹材料IIP-PDMC/SiO₂对PO₄^3-离子具有特异的识别选择性与优良的结合亲和性, 相对于对比离子高锰酸根离子, IIP-PDMC/SiO₂对PO₄^3-离子的识别选择性系数为9.58.

Preparing Surface Anion-imprinted Material Based on Ion Exchange and Surface-initiated Graft-polymerization and Studies on Its Recognition Character

The molecularly imprinted polymers(MIPs) synthesized by conventional bulky imprinting methods suffer from several limitations,such as time-consuming preparation process,poor site accessibility to the target molecules and the lower binding capacity for the target molecules.To overcome these problems in bulking imprinting,in this work,a novel surface-ion imprinting method that not only is simple but also highly effective,is put forward and found.The coupling agent γ-aminopropyltrimethoxysilane(AMPS) was bond onto the surface of silica gel particles,and amino groups were introduced onto the surfaces of silica gel particles,obtaining the modified particles AMPS-SiO2.In aqueous solution,the molecules of the cationic monomer methacryloxyethyltrimethyl ammonium chloride(DMC) were first combined around the template ion,phosphate ion,by right of ion exchange action.A redox initiating system was constructed by the amino groups on AMPS-SiO2 and ammonium persulphate in the solution,and free radicals were produced on the surfaces of silica gel particles.These free radicals initiated the monomer DMC and the crosslinker N,N’-methylene bisacrylamide(MBA) to be graft-copolymerized and crosslinked,and the surface-imprinting of phosphate ion was realized.After removing the template ions,PO43-ion surface-imprinted material IIP-PDMC/SiO2 was obtained.Both permanganate ion,4 MnO-ion,and PO43- ion are isoelectronic bodies.Their chemical structures are similar and their configurations are the same,but their sizes are different.In this work,4 MnO-ion was used as contrast ion,and both static and dynamic methods were adopted to study the binding properties and ion recognition character of IIP-PDMC/SiO2 for PO43-ion.The experiment results show that IIP-PDMC/SiO2 have specific recognition selectivity and excellent binding affinity for PO43-ion,and its selectivity selectivity coefficients for PO43- ion with respect of 4 MnO-ion is 9.58.Besides,IIP-PDMC/SiO2 has excellent elution property,with NaCl solution as eluent,the desorption ratio of PO43- ion reach 99.53% in 20 BV.