Preparation of Molybdate Anion Surface-Imprinted Material for Selective Removal of Molybdate Anion from Water Medium

Abstract

A MnO4– anion surface-imprinted material was prepared with the new surface-imprinting technique of “pre-graft polymerizing and post-crosslinking/imprinting” for the selective removal of molybdate anions from a water medium. Monomer dimethylaminoethyl methacrylate (DMAEMA) was first graft-polymerized on micron-sized silica gel particles by using a surface-initiated graft-polymerization method, resulting in the grafted particles PDMAEMA/SiO2. Subsequently, the grafted macromolecule PDMAEMA was quaternized with epichlorohydrin as a reagent, and the quaternization transform of the grafted particles was realized, obtaining the functional grafted particles QPDMAEMA/SiO2, on which original tertiary amine groups had been transformed into quaternary ammonium groups. The adsorption property of the functional grafted particles for molybdate (MoO42– anion) was examined. On this basis, the MoO42– anion imprinting toward the functional macromolecules QPDMAEMA was conducted with 1,6-hexanediamine as a cross-linker, and MoO42– anion surface-imprinted material IIP-QPDMAEMA/SiO2 was obtained, namely, MoO42– anion surface-imprinted material IIP-QPDMAEMA/SiO2 was prepared with the “pre-graft polymerizing and post-crosslinking/imprinting” method. The ion recognition and combination characters of IIP-QPDMAEMA/SiO2 particles were researched in depth. The experimental results show that this MoO42– anion surface-imprinted material has specific recognition selectivity and combination affinity for the template ion, the MoO42– anion. Relative to the two contrast anions, WO42– and MnO4–, the selectivity coefficients of IIP-QPDMAEMA/SiO2 for the MoO42– anion were 6.41 and 5.39, respectively, displaying high ion recognition ability of this imprinted material.