The Study Of Gas-Phase Photocatalytic Oxidation Of Aniline With Nano-TiO₂ Photocatalyst

The paper has reviewed the most recent progress on the research of nanometer semiconductor catalysts. The current development of nano-TiO₂ photocatalyst has been considered including the preparation of catalyst and the application in degrading aniline. In this thesis, we mainly focus on the study of the gas-phase photocatalytic oxidation of aniline with nanometer TiO₂ thin film and the photocatalytic oxidation mechanism of aniline with the TiO₂ thin film is briefly discussed.The gas-phase photocatalytic oxidation of aniline on a new kind of nano-TiO₂ thin film was investigated. The photocatalytic thin film was prepared on the glass fibre cloth with two methods. The first method was the water glass as binders and dilute H2SO4 solution as solidifying reagent, and then nano-TiO₂ was loaded on the glass fibre cloth. Another method was that nano-TiO₂ crystal was directly loaded on the glass fibre cloth making use of non-crystal nano-TiO₂ colloid without binders and solidifying reagent. The nano-TiO₂ thin film's surface characters were observed by scanning electron micrograph (SEM). The photocatalytic degradation of gaseous aniline on the nano-TiO₂ thin film was carried out in UV illumination. Some important factors affecting the photocatalytic degradation were also studied such as the source of lamp, the concentration of TiO₂, the initial concentration of aniline, and water vapour existing. The experimental results indicated that the degradation rate of aniline reached 84.7% with 5% TiO₂ after UV-irradiation for 7h. If we added water vapour, the higher degradation rate of aniline would reach 94%. Furthermore, the photocatalytic activity with the nano-TiO₂ thin film prepared by the second method was higher than that by the first method. The partial intermediate products were absorbed on TiO₂ surface, which resulted in catalyst deactivation. But when it was irradiated under UV-illumination or solar irradation for some time, the catalyst could be reused without the loss of catalytic activity.In addition, the intermediate products of Photocatalytic oxidation of aniline were detected by Fourier transform infrared spectroscopy (FT-IR), Hydrogen¹ nuclearmagnetic resonance (tf-NMR), and High performance liquid chromatography (HPLC) . According to these detected intermediate products, we briefly presumed the photocatalytic oxidation mechanism of aniline with nanometer TiC>2 thin film.