Enhancement of peroxymonosulfate activation and utilization efficiency via iron oxychloride nanosheets in visible light

Inspired by the photosensitivity and self-heal properties of iron oxychloride (FeOCl), we used photocatalysis coupling peroxymonosulfate (PMS) activation for effective aquatic decontamination in a cost-efficient and environmentally friendly method. Synthesized FeOCl was appointed to activate PMS to degrade bisphenol A (BPA, 2,2-bis(4-hydroxydiphenyl) propane) persistently under visible light. The best performance of FeOCl/PMS/Vis system was ∼100% BPA degradation efficiency which achieved in 20 min. The BPA removal efficiency had a positive correlation with the dosages of FeOCl and PMS, but negatively related to BPA concentration. The FeOCl/PMS/Vis system also presented impressive degradation performance at a wide pH range (pH = 3–11) and showed well excellent stability and reusability. The addition of either bicarbonate or chloride had impressive promotion effect on BPA removal. The reaction mechanism of FeOCl/PMS/Vis system was studied deeply. PMS was activated to generate active radicals (SO4− and HO) by Fe(II) of FeOCl for BPA degradation. Then the as-formed Fe(III) was reduced to Fe(II) via trapping photoexcited electrons in conduction band (CB) of FeOCl, which effectively inhibited the recombination of photo-generate charges and the pollutants oxidation would recur via facilitating the Fe(II)/Fe(III) redox recycle. Thus, the activation and utilization efficiency of PMS was effectively improved. This work indicated the FeOCl/PMS/Vis system was a promising application in wastewater treatment.