Preparation and characterization of natural zeolite supported nano TiO2photocatalysts by a modified electrostatic self-assembly method

Abstract

Natural zeolite supported nano TiO2 photocatalysts were prepared by a modified electrostatic self-assembly (ESA) method. First, γ-mercaptopropyltrimethoxysilane with sulfhydryl (―SH) functional groups was modified on the zeolite powders by using a ‘dry process’. Second, silane with ―SH functional groups was oxidized to sulfonate (―SO3H) groups by using a hydrogen peroxide/glacial acetic acid mixed solution, and the surface of ―SO3H silane–zeolite was electronegative charged due to the ionization of ―SO3H. Third, the hydrolytic titanium polycation from TiCl4 solution assembled onto the electronegative charged zeolite under electrostatic attraction in the reaction solutions. Finally, zeolite supported nano TiO2 photocatalysts can be obtained after the above compounds calcined at certain temperature. The samples were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface areas, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence (XRF). The photocatalytic activities of the samples were evaluated by the degradation of methyl orange in aqueous solution. The results showed that ESA method effectively improved the composite efficiency of zeolite with TiO2. The photocatalysts prepared by ESA method exhibited higher photocatalytic and recycling activities than that of traditional method. Copyright © 2014 John Wiley & Sons, Ltd.