Photocatalytic degradation of organophosphorus pesticides using thin films of TiO 2

This paper studies the feasibility of photocatalytic degradation of organophosphorus pesticides using thin films of TiO 2 . The results show that 0·65 × 10 −4 mol dn −3 of dichlorvos, monocrotophos, phorate, parathion can be completely photocatalytically degraded into PO   4 3−within a short time under illumination with a medium pressure mercury lamp of 375 W. The effect of parameters such as he amount of TiO 2 attached, initial concentration of organphosphorus pesticides, initial pH, amount of air flow, concentrations of H 2 O 2 and Fe 3+ on the photocatalytic degradation are studied. The possible mechanisms of photocatalytic degradation are discussed. It is our assumption that the degradation reactions occur on the surface of TiO 2 via primary produced oxidizing species such as the OH radical and O   2 2− , after 80 h illumination, there is no significant loss of the photocatalytic activity of TiO 2 .