Ion-imprinted mesoporous silica hybrids for selective recognition of target metal ions

A novel ion-imprinted functional ligand derivative bearing periodic mesoporous organosilica (IIPMO) was obtained using a sol-gel process from a chemically synthesized organopolysilane precursor with a metal template (Co2+ ion) imprinted ligand centre with tetraethylorthosilicate (TEOS) and cetyltrimethylammoniumbromide (CTAB) as a structural directing surfactant under basic conditions. The imprinted metal template was easily leached out from the hybrid materials during an acid treatment, which resulted in a template-free ion-imprinted network in the PMO pore wall framework with an unaltered particle size and morphology. The ion-imprinted hybrid PMO materials were characterized by X-ray diffraction, Fourier transform-infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, solid-state Si-29 and C-13 cross polarization magic angle spinning nuclear magnetic resonance spectroscopy, N-2 adsorption-desorption analysis and elemental analysis. Furthermore, the removal of the imprinted metal template was confirmed by inductively coupled plasma-atomic emission spectroscopy. The selective rebinding ability of the template ions on the ion-imprinted PMO hybrid adsorbents was examined using a cobalt nitrate solution. The rebinding results showed that the selective efficiency of Co2+ ions on the IIPMOs were 10.1, 7.4 and 9.3 for Cu2+, Cd2+ and Zn2+, respectively. (C) 2013 Elsevier Inc. All rights reserved.