Preparation of Fe₃O₄@ion imprinted poly(MMA-HPMA-DVB) magnetic composite and its selective adsorption to Ni(Ⅱ)

An amino-functionalized Fe₃O₄-ion imprinted poly(methyl methacrylate (MMA)-3-(2-amino-ethylamino)-2-hydroxypropyl methacrylate (HPMA)-divinylbenzene(DVB)) magnetic composite (Fe₃O₄@ion imprinted poly(ⅡP) (MMA-HPMA-DVB)) was synthesized via ultrasonic assisted suspension polymerization with nickel(Ⅱ) as ion imprinting template. The Fe₃O₄@ⅡP(MMA-HPMA-DVB) was characterized by EA, XRD, FTIR, TEM, TG and VSM. The application for its adsorption properties on Ni(Ⅱ) from water was investigated. The results show that the Fe₃O₄@ⅡP(MMA-HPMA-DVB) has an average size of 100 nm, with the saturation magnetization intensity of 43.8 emu/g. The carbonyl group of the co-monomer methyl methacrylate (MMA) can connect with the hydroxyl group at the surface of the nano-Fe₃O₄ via hydrogen bonds, which would be favorable to the formation and stabilization of the coreashell structure of the Fe₃O₄@ⅡP(MMA-HPMA-DVB). The adsorption capacities were investigated by adsorbing the Ni(Ⅱ) from aqueous solutions, which demonstrate an excellent adsorption capacity with the maximum adsorption capacity (q_m,c at 500 mg/g, q_m,e at 478 mg/g) much higher than that of amino-functionalized nano-Fe₃O₄-none-ion imprinted polymer magnetic material (Fe₃O₄@NIP(MMA-HPMA-DVB) (q_m,c at 90.9 mg/g, q_m,e at 83.8 mg/g). The isothermal adsorption curve mainly obeys the Langmuir mode. The adsorption kinetic studies show that the adsorption processes reach the equilibrium within 5 min and the kinetic data are well fitted to the pseudo-second-order model. There is almost no interference by the coexisting components in water for the adsorption of Ni(Ⅱ), with imprinting factor (α) at 1.9, and selectivity factor (β) more than 7.7 for several kinds of common co-existing ions, respectively. The Fe₃O₄@ⅡP(MMA-HPMA-DVB) is an ideal candidate for adsorption and recycle Ni(Ⅱ) from aqueous solution.