Rapid synthesis of titania-silica nanoparticles photocatalyst by a modified sol-gel method for cyanide degradation and heavy metals removal

摘要

Titania-silica (TiO_2-SiO_2) photocatalyst was prepared by a modified sol-gel technique. Titania sol was firstly synthesized by acid hydrolysis of a TiCl_4 precursor instead of titanium alkoxides. The titania sol was further modified with SiO_2 to obtain a modified catalyst. The as-prepared TiO_2-SiO_2 catalyst demonstrated a remarkable photocatalytic activity toward degradation of cyanide and heavy metals removal (Cr(III), Co(II) and Pb(II)). The influence of the preparation parameters; the reaction time, the calcination temperature and time, the [H~+]/[Ti] ratio, the pH value and the acid concentration on the structural and chemical properties of the catalyst was investigated in details. The catalytic performance was found to depend essentially on the catalyst and target concentrations and the reaction time. The as-synthesized catalyst was characterized by a variety of techniques including surface area measurement, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) transmission electron microscopy (TEM) and ultraviolet-visible (UV-vis) spectroscopy measurements. Results of the synthesis and characterization of TiO_2-SiO_2 catalyst and its photocatalytic performance are presented and thoroughly discussed.