Preparation And Photocatalytic Activity Of Composite Photocatalyst

As rapid development of industrial and agricultural production, environmental pollution has become more and more serious all over the world. Thus, to study and develop clean and effective treatment technology for polluted water becomes a study topic of environmental science. Photocatalytic technique based on semi-conductor catalysts, especially TiO2and ZnO, has attracted worldwide attentions for its excellent performance.This thesis reviewed a progress on study and applications of semiconductor photocatalytic technology. The catalytic principle, factors affecting photocatalytic activity and preparation methods of the catalysts were introduced. Several composite semiconductor photocatalysts were synthesized respectively by sol-gel, chemical precipitation and adsorption methods and characterized with scanning electron microscopy(SEM), transmission electron microscopy(TEM) and X-ray diffraction(XRD) and their photocatalytic properties to the degradation reactions of some dyes were studied.1. ZnO and TiO2/AC composite photocatalysts were prepared with zinc acetate, tetrabutyl orthotitanate and activated carbon (AC) as raw materials by a sol-gel method. Effects of doping amounts of ZnO and AC on photocatalytic activity of the composite catalyst were suited and the experimental conditions were optimized. When using ZnO (9.52%)-TiO2/AC(40%) as catalyst, the removal rate of methyl orange aqueous solution of10mg·L-1reached87%within3h under ultraviolet irradiation.2. With zinc acetate and attapulgite as raw materials, ZnO/ATP composite photocatalyst was prepared by adsorption and chemical precipitation methods, this catalyst showed a high degradation efficiency for methylene blue solution under ultraviolet light irradiation.3. Using a sol-gel method, composite photocatalyst TiO2/bentonite-AC was successfully fabricated and influences of the experimental conditions on the photocatalytic performance of the product were investigated in detail. Using TiO2/bentonite (31.67%)-AC(18.33%) as a catalyst, the degradation efficiency of methylene blue solution (20mg·L-1) exceeded87%.