Singlet oxygen-dominated dye degradation by cobalt-functionalized ceramic hollow fiber membrane via peroxymonosulfate activation

The efficient treatment of dye-containing wastewater remains a critical environmental issue, primarily due to its biological toxicity to aquatic microorganisms and high chromaticity. In this work, two types of Co₃O₄-functionalized ceramic hollow fiber membranes were designed to activate peroxymonosulfate (PMS) for the efficient removal of dyes from water. Compared to the static-deposited membrane (SCHFM), the dynamic-deposited membrane (DCHFM) demonstrated a higher loading capacity and more uniform distribution of Co 3 O 4 on both the surface and internal pores, leading to a significant enhancement in catalytic performance. Under optimal operating parameters, the DCHFM achieved over 98% removal of rhodamine B (RhB) during the filtration. Radical quenching and electron paramagnetic resonance (EPR) confirmed the involvement of multiple reactive oxygen species, including singlet oxygen ( 1 O 2 ), hydroxyl radical (HO•), sulfate radical (SO 4 •− ) and superoxide radical (•O 2 − ), with 1 O₂ identified as the predominant reactive species. Furthermore, the functionalized membrane exhibited outstanding operational stability and reusability with negligible cobalt leaching. The findings of this study provide a high-performance catalytic membrane system for the advanced purification of industrial wastewater.