Characteristics of Thiol-Functionalized Mesoporous Silica and its Application to Silver and Cadmium Ion Removal

Abstract

—An uptake of silver and cadmium from aqueous solutions by ion exchange on functionalized large pore mesoporous silica has been studied. Mesoporous silica with large pore (about 6nm) was synthesized by condensation of siliceous solution using nonionic oligomeric polyethylene glycol block copolymer (P123) as surfactant in acidic medium and was functionalized by 3-mercaptopropyltrimetoxysilane (MPTMS) on surface of silica for good selectivity and high adsorption capacity. The result of nitrogen gas adsorption (BET) and transition electron microscopy (TEM) show that silica adsorbate have ordered mesoporous structure with uniform pore size distribution. 29Si MAS NMR, TG and FT-IR confirm the functionalization of MPTMS on the surface of mesoporous silica. The removal efficiency of metal in various concentration of metal cations in aqueous solution was investigated and it is determined that in various concentration range, adsorption amount of metal cations on mesoporous silica match to Freundlich and Henry adsorption isotherm data which are used for calculation of ion exchange parameter.