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

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.