(23i) Photocatalytic Decomposition of Trichloroethylene in Air by Nanostructured TiO2 Films

The gas phase photocatalytic oxidation of trichloroethylene (TCE) was studied using an immobilized TiO2 film reactor. TiO2 nanoparticles with different physicochemical properties were synthesized via a simple sol-gel method followed by calcination at 300-800 °C. The TiO2 nanoparticles were immobilized on glass substrates (6 mg/cm2) and incorporated into a flat-plate photocatalytic reactor irradiated by UV-365 nm radiation and equipped with a gas chromatograph (GC-FID) and on-line sampling valves. The effects of the surface area and crystal phase of TiO2 and UV light intensity on the decomposition of TCE were investigated and compared with the activity of commercial TiO2 (Degussa P-25) reference catalyst. The results showed that the TiO2 films calcined at temperatures up to 600°C exhibited a gradual increase in TCE degradation efficiency due to their increase in anatase crystal phase. Further calcination at temperature higher than 600°C transformed the crystal phase of TiO2 from anatase to rutile and a significant decreased in activity was observed. The photocatalytic activity of TiO2 films calcined at 400-600°C was much higher than that of P-25 film. This was attributed to the higher surface area and porosity of the calcined catalysts. The TCE degradation rate was found to be linearly depended on the UV light intensity in the range of 0.5-2.1 mW/cm2. In the presentation, we will discuss details on the synthesis, characterization, and immobilization of the TiO2 nanoparticles and the photocatalytic degradation of TCE.