Catalytic degradation of p-nitrophenol by magnetically recoverable Fe3O4 as a persulfate activator under microwave irradiation

In this study, Fe 3 O 4 and microwave (MW) were combined to activate persulfate (PS) for the removal of organic matter, resulting in the enhanced degradation of p -nitrophenol (PNP) in solution. During the preparation of Fe 3 O 4 , the effect of sodium acetate was examined, and the results showed that the concentration of sodium acetate had little effect on the catalytic activity of the Fe 3 O 4 /PS/MW system but did have an effect on the Fe 3 O 4 yield. In addition, with regards to the representative environmental factors, the degradation experiment showed that humic acid and the co-existing anions of chloride, sulfate, nitrate, and phosphate had little effects on p -nitrophenol removal; however, carbonate had a negative effect. In addition, the Fe 3 O 4 /PS/MW system performed well in the initial pH range of 3.0–9.0. According to the quenching experiment and electron paramagnetic resonance (EPR) detection, sulfate radicals and a minority of hydroxyl radicals play dominant roles in the degradation process. In addition, the role of Fe 3 O 4 was confirmed to take part in the degradation process by X-ray photoelectron spectroscopy (XPS) analysis. Because of the good performance observed in the water matrices of tap water and the Songhua River, these results demonstrate the potential application of the Fe 3 O 4 /PS/MW system for wastewater treatment .