Photocatalytic degradation of trace

Adsorption and Sensitization Effects in Photocatalytic Degradation of Trace Contaminants... 

Guo et al. reported that trace amoimts of aqueous organochlorine pesticides, such as hexachlorocyclohexane (HCH), could be totally degraded and mineralized into CO2 and HCl by near-UV irradiation of a suspension of Mg/Al LDH intercalated with paratungstate anions [108]. They demonstrated that photocatalytic degradation of the pesticide occurs in the interlayer galleries. It was also found that Zn/Al/W(Mn) mixed oxides, formed by calcination of POM-intercalated Zn/Al LDHs [109], exhibited higher photocatalytic activity in the degradation of HCH compared with the POM-LDH precursors. 

The photocatalytic degradation of TCE was studied in the gas phase for the first time by Dibble and Raupp (1990,1992). A positive order was found with respect to the molar ratio of oxygen and TCE, whereas for water a negative order of reaction was observed. No intermediate products were observed. It was clear that traces of water were required in order to preserve photocatalytic activity for long time, however, high relative humidity reduced the reaction rate. The rate could be described by a modified LH equation ... 

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