The effect of Pt nanoparticles distribution on the removal of cyanide by TiO2 coated Al-MCM-41 in blue light exposure

Abstract

With an aim to enhance the photocatalytic activity, Pt loaded TiO2–Al-MCM-41 catalysts with high surface area were synthesized by a multistep route. The waste of the rice processing, rice husk (RH), was used as the precursor for the extraction of silica. The diffuse reflectance and photoluminescence spectroscopy revealed the extension of the absorption edge in the visible region and exciton trapping nature of the dispersed platinum. The structural analysis was carried out by XRD, whereas X-ray photoelectron spectroscopy identified the chemical states of the components of the synthesized powders. The BET surface area measurements revealed the reduction in the surface area and pore volume with the increasing platinum loading. TEM micrographs showed the uniform distribution of TiO2 and Pt nanoparticles at the surface of Al-MCM-41. The photocatalytic efficiency of the synthesized powders as photocatalysts was obtained for the removal of 100 ppm CN− from aqueous solution in fluorescent blue light exposure. Compared to unsupported TiO2, the Pt-loaded catalysts exhibited substantially high activity for the removal of CN−. A plausible mechanism for the removal of cyanide ions was proposed. The catalysts showed excellent stability and reproducibility in the successive use. Keywords: Al-MCM-41, Rice Husk, Pt loading, TiO2 loaded Al-MCM-41, Cyanide