Photocatalytic oxidation of dichlorvos in the presence of hydrogen peroxide and ferrous ion

The photocatalytic oxidation of dichlorvos has been investigated with two different reactors. The reactor using 254 nm light is a system with TiO₂ suspensions. The 360 nm light is used as the light source of the fixed system which was TiO₂ coated on the inner surface of the reactor. In terms of quantum yield, the 254 nm radiation is more effective for dichlorvos oxidation than the 360 nm light. The effect of H₂O₂ on dichlorvos oxidation shows a negative performance. The influence of H₂O₂ on the photocatalytic oxidation of dichlorvos is greater in the fixed system than that in the suspension system. The ferrous ions can induce the photo-Fenton-type reaction. However, the photocatalytic oxidation of dichlorvos will be inhibited slightly at the concentration of 1.0 × 10⁻⁵ M Fe⁺². This result is explained in terms of the net production of hydroxyl radical.