[Synergistic Reaction Mechanism of Cu0@Fe3O4 Activated PMS for Degradation of p-nitrophenol].

A Cu0/PMS system mainly relies on the leaching of copper ions to degrade the pollutants and adapt to the narrow pH range (<7). To solve this defect, we studied the properties and reaction mechanism of Cu0@Fe3O4 magnetic core-shell material, which was successfully prepared using co-precipitation method, taking PNP as the target pollutant. The results showed that: ① a degradation rate of 96% can be achieved within 60 min for 5 mg ·L-1 PNP, 200 mg ·L-1 Cu0@Fe3O4, and 0.5 mmol ·L-1 PMS at a natural pH value (5.65); ② the Cu0@Fe3O4/PMS system can be regarded as a heterogeneous reaction system because TCu, TCu+, and iron leaching were almost negligible; ③ on comparing the performance of the Cu0@Fe3O4/PMS system and Cu0/PMS system in the pH range of 3 to 11, it was discovered that the method by which Cu0 activates the PMS to degrade the PNP was successfully changed by coating a layer of Fe3O4. The Cu0@Fe3O4/PMS system has a good degradation performance towards PNP in the pH range of 5-9; ④ SO-4 · and HO · existed in the reaction system, and their contribution rates to the reaction system were 34% and 60% ; HO · was the dominant free radical; ⑤ A bimetallic synergy exists between Fe and Cu. The presence of Cu(Ⅰ) can promote the reduction of Fe(Ⅲ) to Fe(Ⅱ), thereby forming a good redox cycle and improving the durability of the reaction system.