3-Aminopropyltrimethoxysilane Functionalized Mesoporous Materials and Uptake of Metal Ions

Abstract

γ-Aminopropyl-functionalized mesoporous materials were synthesized by chemical modifcation of a HCl-ethanol washed mesoporous silica (OSU-6-W) with 3-aminopropyltri-methoxysilane (APTMS). The synthesized inorganic-organic hybrids were characterized by solid state ²⁹Si NMR spectroscopy, a titration method and elemental analysis of the modified samples. The average numbers of pendant groups were found to be 2.47 and 4.71 groups/nm². Surface area analysis showed that these materials have channel diameters of 43.6 and 36.2 Å and surface areas of 1023 and 709 m²/g. Infrared spectroscopy, solid state NMR for ¹³C and ²⁹Si nuclei and X-ray diffraction patterns are in agreement with the success of the preparation of organicallymodified mesoporous silicas. Adsorption experiments of Cu²⁺, Zn²⁺ and Cd²⁺ shows a remarkably high adsorption capacities with an increase in the surface density of amino groups and affected by the pH of the medium, surface areas and pore sizes.