Treatment of p-nitrophenol in water by Fenton-like reaction with microwave coupling

In order to avoid the narrow pH range in the traditional Fenton process, the CuO catalyst was synthesized and used in the microwave-assisted Fenton-like process to remove the p-Nitrophenol (PNP), which is harmful to the environment and difficultly biodegradable. The effects of the H₂O₂ dosage, CuO dosage, microwave power, irradiation time, and initial pH on the degradation of PNP were investigated in detail. The optimal values of operating parameters were found at a H₂O₂ concentration of 0.06 mol/L, a CuO concentration of 0.3 g/L, a microwave power of 125 W, and a pH of about 6without adjusting the initial pH. Under the optimal conditions, the removal efficient of PNP reached 92% and the TOC removal was 63% after 6min of irradiation when the initial concentration of PNP was 50 mg/L. Compared with the other oxidation processes, the microwave can enhance the ·OH production from the Fenton-like process, resulting in the improved removal efficiency of PNP. As a new kind of Fenton-like process, the microwave-assisted one using the CuO catalyst can overcome the limitation of the narrow pH range in the traditional Fenton reaction, and broaden the application of the Fenton process in wastewater treatment.