Photocatalytic degradation of chlorinated compounds in water.: Effect of the number of the repeated dip-coating for the TiO2 thin-film on the degradation of TCE

Photocatalytic degradation of trichloroethylene(TCE) was studied by using TiO2 thin film coated on the surface of Pyrex glass tube. Two types of TiO2 coated photocatalyst were prepared; one is Pyrex tube coated with thin film only on the outside surface of the tube and the other is that coated with TiO2 thin film on both sides (inside and outside) of the tube. The TiO2 film was coated by means of dip-coating in sol-gel process. The thickness of TiO2 was changed by repeating the dip-coating process. Relations between the thickness and transmittance were determined. TiO2 films of an optimum thickness showed high photocatalytic activities under the illumination of blacklight fluorescent lamps from the outside of the tube. The photocatalytic activities of TiO2 thin film on inside of the tube is concerned with the photo-reaction.