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/Fe 3+ , 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 Fe 3+ 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 photonFenton 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.