The photocatalytic degradation of trichloroethane by chemical vapor deposition method prepared titanium dioxide catalyst

The purpose of the investigation was to study the photocatalytic reaction of trichloroethane using a TiO(2) catalyst deposited in an annular reactor by the chemical vapor deposition (CVD) method. The experimental results indicated the highest decomposition rate of the trichloroethane was 2.71 mumol/(s m(2)) and the conversion ratio reached a maximum of 99.9%. When the humidity was below 154 muM, the reaction rate slightly increased with increasing humidity. However, the reaction rate decreased as the humidity increased > 154 muM. Oxygen played a role as an electron acceptor in the reaction, and reduced the recombination of the photogenerated electron-hole pairs. Therefore, the reaction rate rose as the oxygen concentration increased. Nevertheless, after the oxygen concentration reached 12%, the reaction rate reached it maximum and was constant in spite of increasing oxygen concentration. As the initial reactant concentration increased, the reaction rate increased, but the conversion ratio dropped. An increase of light intensity resulted in an increase in the number of photons and thus increased the reaction rate. Accordingly the decomposition of trichloroethane could be fitted by the semi-empirical bimolecular Langmuir-Hinshelwood model. Moreover, the reaction rate was proportional to the 0.48-order of the light intensity. (C) 2002 Elsevier Science B.V. All rights reserved.