Photocatalytic oxidation of chlorinated hydrocarbons in water

The impact of surface modification on the photocatalytic activity of two different commercial TiO2 catalysts is studied using different impregnation methods with platinum, silver and iron oxide. The Degussa P-25 TiO2 as received is more active than Aldrich TiO2, but the photocatalytic activity of Aldrich TiO2 can be greatly increased by surface modification with platinum or silver. No improvement in the photocatalytic activity has been observed for the Degussa P-25 TiO2 impregnated with platinum. The most active photocatalyst for the trichloroethylene (TCE) destruction is Aldrich TiO2 loaded with 1.0 wt% platinum using a photoreduction method. Similar destruction efficiency was obtained for the destruction of para-Dichlorobenzene (p-DCB) using platinized Aldrich TiO2 as catalyst. A kinetic model developed in this study can quantitatively describe the effect of light intensity and catalyst dosage on the photocatalytic oxidation of TCE. The reaction rate is proportional to the half-order of incident light intensity for the light intensity within the range studied (83.2-743.3 mW/L). The optimum catalyst dosage increases as the incident light intensity increases. (C) 1997 Elsevier Science Ltd.