Study On Dye-sensitized TiO₂ Visible Light Photocatalytic Degradation Of Organic Pollutants

The application of TiO₂ on photocatalytic degradation of organic contaminant is a promising technology of wastewater treatment recently. It is used as photocatalyst extensively because of its low cost, none secondary pollution caused, high photoactivity and good photochemical stability. while easily compound of electron-hole, low quantum efficiency and poor utilization of visible light limit its widespread application, so we considered using dye-sensitized TiO₂ to enhance its range of light response and improve its photocatalytic efficiency.The thesis focused on treating the phenol with the P-25 TiO₂ photocatalyst under simulated sunlight and UV, analysed the external influenceing factors include amount of catalyst, initial concentrateion of phenol, light source, pH of solution etc. At the same time, investingated the photocatalytic degradeation of phenol with TiO₂ in the presence of dyes, The dyes with good modification performance on TiO₂ were choosed. The machanism of sensitizing TiO₂ with dye to enhance the visible light photodegradation efficiency of phenol and sodium dodecylbenzenesulfonate (DBS) was discussed.Results indicated that: The phenol degradation follows the elementary kinetics discipline, the degradation rate decreased with the increase of initial concentration of phenol at the low concentration, The photocatalytic activity of TiO₂ under UV irradiation was higher than Xe lamp. The photodegradation rate initially increased with the increase of amount of catalyst and then decreased.The influences of dyes on TiO₂ visible light photoactivity were different. Alizarin red and acid magenta dyes could increase the phodegradation efficiency of phenol. when 10mg/L alizarin red were added into the system, the phenol removal increased to 91% from 17%, and acid magenta have the same effect. While the adding of other dyes such as methylene blue and acidic chromium haran would produce kinds of middle product or inhibit the degradation efficiency of phenol. So in this paper, we mainly discussed the promoting effect and degradation mechanism with adding alizarin red and acid magenta. Meanwhile, the method was put into treating surfactant(DBS), the effect was obvious, so photocatalytic oxidation combines with dyes is regarded as future advanced oxidation technology in environmental protection...