Application of heterogeneous photo-Fenton process for the mineralization of imidacloprid containing wastewater

The imidacloprid was mineralized by heterogeneous photo-Fenton process in a three-phase fluidized bed reactor using waste iron oxide as catalyst. The effects of catalyst loading, dosage of H₂O₂ and pH were investigated to determine the optimal experiments conditions. The results revealed that TOC removal efficiency increases with an increase in H₂O₂ dosage of up to 105.0 mM, an increase in catalyst dosage from 1.0 to 5.0 g L⁻¹, and a decrease in pH from 5.0 to 3.5. Under the optimal conditions, 97.7% TOC removal was achieved in 6 h under 254-nm UV irradiation. Moreover, recycling experiments indicated that the waste iron oxide had a good stability and the TOC removal of pesticide yielded more than 80% under the fourth recycles.