THE GAS-PHASE PHOTOCATALYTIC MINERALIZATION OF BENZENE ON POROUS TITANIA-BASED CATALYSTS

Photocatalytic degradation of benzene in oxygen-containing gaseous fee d streams was investigated using titania and platinized (0.1 wt.-%) ti tania photocatalysts. The titania catalyst was synthesized using sol-g el techniques. Results of this study indicate that, when using this pa rticular photocatalyst, benzene was oxidized to carbon dioxide and wat er without forming any detectable organic reaction products in the rea ctor effluent, although only some of the benzene reacted. Both the ove rall conversion of benzene and its mineralization were improved by pla tinizing the titania. When the titania catalyst was platinized, both p hotocatalytic and thermocatalytic reactions were promoted. Rates of ph otocatalytic reactions were significantly enhanced at reaction tempera tures between 70 and 90 degrees C, while at temperatures above 90 degr ees C the rates of thermocatalytic oxidation reactions were noticeably increased. It proved possible to obtain the continuous and essentiall y complete mineralization of benzene by using the platinized titania c atalyst and optimizing such parameters as the reaction temperature, sp ace time, and the concentrations of oxygen and water vapor in the feed stream.