Influence of ph and h₂o₂ dosage on the decomposition of carbofuran during the photo-fenton process

The effects of hydrogen peroxide dosage and pH on the decompostion of aqueous carbofuran (50 mg L^-1) during the photo-Fenton process, i.e. a combnination of UV irradiation with H₂O₂/Fe³⁺, were evaluated. The efficiency of carbon removal by the photo-Fenton process was estimated based on the reductions in dissolved organic carbon (DOC) and carbofuran concentrations. More than 90% carbofuran removal and 33% DOC reduction were observed within 100 min of the photo-Fenton reaction at pH 3, H₂O₂ dosage of 0.25 mg L^-1 min^-1 and Fe³⁺ addition of 35 mg L^-1. The photo-Fenton reaction was speeded-up at 4 mg L^-1 min^-1 of H₂O₂ dosage, beyond which a decrease in the carbofuran domposition efficiency was observed. At 4 mg L^-1 min^-1 of H₂O₂ dosage, 100 and 94% of carbofuran removal and DOC reduction, respectively, were observed within 120 min of the photon-Fenton reaction. Overall, a rapid decomposition as well as mineralization of carbofuran could be achieved at 4 mg L^-1 min^-1 of H₂O₂ dosage and pH 3.