Iron molydate catalyzed activation of peroxymonosulfate for bisphenol AF degradation via synergetic non-radical and radical pathways

Though molybdate oxides have been demonstrated as desirable catalysts for environmental remediation, the mechanism of catalytic activation of peroxymonosulfate (PMS) by iron (II) molybdate (FeMoO4) remains unclear. In this study, FeMoO4 was synthesized and applied for the activation of PMS to degrade bisphenol-AF (BPAF). FeMoO4 showed excellent catalytic activity, high stability, and superior mineralization. The influence of operation parameters (i.e., FeMoO4 dosage, PMS concentration, initial pH, co-existing anions, and temperature) on the removal of BPAF were also investigated in detail. Furthermore, the possible oxidation mechanism was proposed via the chemical quenching tests and electron spin resonance (ESR) analysis, which certified that both free radical (SO4-center dot and center dot OH) and non-radical (O-1(2)) were the main reactive oxygen species for degrading BPAF. X-ray photoelectron spectroscopy (XPS) analysis indicated that the radicals were mainly generated via the continuous circulation of Fe3+/Fe2+ and Mo6+/Mo4+ redox cycles to enhance PMS activation. Finally, the degradation pathways of BPAF was proposed based on LC/MS results. This work showed the notable potential of the FeMoO4/PMS system for degrading organic contaminants in the environment remediation and would promote the understanding of the mechanism of Fe-based molybdate in advanced oxidation. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, FeMoO4 was synthesized and demonstrated to have excellent catalytic activity for the activation of PMS to degrade BPAF. The oxidation mechanism was proposed to involve free radical (SO4· and ·OH) and non-radical (O-1(2)) species. XPS analysis confirmed that the radicals were mainly generated through Fe3+/Fe2+ and Mo6+/Mo4+ redox cycles, enhancing PMS activation.