Activation of peroxymonosulfate and recycled effluent filtration over cathode membrane CNFs-CoFe₂O₄/PVDF in a photocatalytic fuel cell for water pollution control

Few studies integrate catalytic membrane in photocatalytic fuel cell (PFC) with peroxymonosulfate (PMS) activation process. In the present work, a novel PFC-membrane reactor system integrating PMS activation (abbreviated as PMS/PFC-MR) was constructed for wastewater treatment, consisting of CNFs-CoFe₂O₄/PVDF membrane cathode (CNFs-CoFe₂O₄/PM) and Ag/ZnO NA/NiF photo-anode. The PMS/PFC-MR with enlarged volume exhibited favorable performance, increased berberine degradation by 65.9% and electricity production by 0.33 V, comparing with PFC-MR after 1 h operation. Relative to CNFs/PM (0.89 h^-1) and PM (0.53 h^-1), the PMS/PFC-MR with CNFs-CoFe₂O₄/PM greatly enhanced rate constant (4.32 h^-1). The results also indicate that recycled filtration over membrane accelerates catalytic degradation of organic pollutant in PMS/PFC-MR. Revealed by the radical quenching and EPR tests, hydroxyl radicals (^•OH), singlet oxygen radicals(¹O₂), superoxide radicals (O₂^•-) and sulfate radicals (SO₄^•-) were all confirmed present and responsible for pollutant degradation in PMS/PFC-MR. Consequently, the PMS/PFC-MR system expands the radical reactions to enhance degradation and electricity generation, due to the synergy of accelerated Co(II)/PMS oxidation with membrane filtration and photo-electro catalysis. This system provides a new efficient strategy towards wastewater treatment with energy recovery.