Synthesis And Photocatalytic Properties Of The TiO₂ Loaded Zeolite Photocatalysts

In this thesis, the first chapter gives an overview of the development in photocatalytic technology and the latest progress of TiO2 loaded zeolite photocatalysts. Titanium dioxide (TiO2) based photocatalysts were prepared by impregnating natural zeolites using a sol-gel technique in this study. The TiO2/zeolite photocatalysts were characterized by using UV-Vis absorption spectrum, FT-IR spectrum, thermogravimetric analysis and differential thermal analysis, UV-Vis diffuse reflection spectrum, X-Ray diffraction and BET surface area analysis etc. The properties of TiCVzeolite photocatalysts were performed by degrading of methyl orange, salicylic acid, Cibacron red and Cibacron yellow under the ultraviolet light irradiation. The experiments indicate that TiCVzeolite photocatalysts have excellent photocatalytic activity. The effect of TiO2 amount on zeolite, intensity of light irradiation, irradiation time, catalysts concentration, initial pH value of methyl orange solution, and the heat treatment temperature of catalysts on the photocatalytic activities was studied. The influence of the presence of strong oxidant species (H2O2) on the process was also investigated. The results show that the photocatalytic activities of TiO2/zeolites can be improved under the condition of lower heat treatment temperature of catalysts, the presence of H2O2 and lower initial solution pH value. In the TiO2/zeolite suspension system, the reaction kinetic laws of the photocatalytic degradation of methyl orange, salicylic acid were studied. It was found the procedure of photocatalytic degradation of methyl orange, salicylic acid followed the first order kinetic relationship and their reaction rate constants were 0.0056min-1, 0.0086mm-1 respectively.The research on photocatalytic performance of TiCVzeolite which modified by doping transition metal ions was carried out. The Fe3+, Ni2+, Ce3+, Cd2+, Cr3+, Cu2+, Zn 2+, Pd 2+ doped TiO2/zeolite photocatalysts were prepared by using a sol-gel technique. Characterization of photocatalysts was done with X-Ray diffraction and UV-Vis absorption spectrum. The photocatalytic reduction of methyl orange was dealt with under the ultraviolet light irradiation in order to examine the photocatalytic activities of the photocatalysts. It was found that the photocatalytic activity of the TiCVzeolite can be enhanced efficiently by doping with the Fe3+, Ni2+, Cr3+, Zn2+, Cd2+, Ce3+, Pd2+, while the photocatalytic activity of the TiCVzeolite catalyst doped with Cu2+ decreased.