磁性Fe_3O_4@SiO_2@CS镉离子印迹聚合物的制备及吸附性能

Preparation and Adsorption Properties of Magnetic Fe_3O_4@SiO_2@CS Cadmium Ion-imprinted Polymer

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.

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%.