磁性Fe3O4@SiO2@CS镉离子印迹聚合物的制备及吸附性能

以SiO2包覆的纳米Fe3O4为载体, 壳聚糖(Chitosan, CS)为功能配体, γ-缩水甘油醚氧丙基三甲氧基硅烷为交联剂, 制备了磁性Fe3O4@SiO2@CS镉离子印迹聚合物(Magnetic ion-imprinted polymer, M-IIP). 采用扫描电镜和红外光谱对该磁性印迹聚合物进行了表征. 结果表明, 壳聚糖在环氧基硅烷交联作用下, 实现了印迹壳层在磁性Fe3O4表面的接枝, 该印迹材料是边长为60~120 nm的立方体. 吸附性能实验表明, M-IIP对Cd(Ⅱ)的吸附符合一级动力学吸附模型; M-IIP对Cd(Ⅱ)/Cu(Ⅱ), Cd(Ⅱ)/Zn(Ⅱ), Cd(Ⅱ)/Pb(Ⅱ)和Cd(Ⅱ)/Hg(Ⅱ)的相对选择系数分别为2.92, 3.43, 8.97和9.20. 原子吸收光谱检测结果表明, 该磁性Fe3O4@SiO2@CS离子印迹聚合物可用于水溶液中Cd(Ⅱ)的分离, Cd(Ⅱ)回收率在98%以上.

Preparation and Adsorption Properties of Magnetic Fe3O4 @ SiO2 @ CS Cadmium Ion-imprinted Polymer

Magnetic Fe3O4@SiO2@CS cadmium ion-imprinted polymer(M-IIP) was prepared on the surface of silica-coated Fe3O4 nanoparticles using chitosan(CS) as functional monomer, and γ-glycidoxypropyltrimethoxysilane(GPTMS) as cross-linker. The imprinted material was characterized with scanning electron microscope(SEM) and infrared spectrum technique. The results indicated that the imprinted layer was grafted on the magnetic Fe3O4 surface, and a cubic morphological characteristic of M-IIP with edge length of 60—120 nm was observed. The selective experiment results show that the adsorption kinetics of M-IIP toward Cd(Ⅱ) is fit to pseudo first-order kinetic isotherms capacity experiment. The relative selectivity coefficient of M-IIP toward Cd(Ⅱ)/Cu(Ⅱ), Cd(Ⅱ)/Zn(Ⅱ), Cd(Ⅱ)/Pb(Ⅱ) and Cd(Ⅱ)/Hg(Ⅱ) were 2.92, 3.43, 8.97 and 9.20, respectively. The M-IIP was employed successfully to extract Cd(Ⅱ) from aqueous solution coupled with atomic absorption spectrometry(AAS) with a recovery of >98%.