Bi2O3/rGO/TiO2 catalytic membrane for advanced treatment of secondary effluent: Insights into EfOM degradation and membrane fouling alleviation

Secondary effluent organic matter (EfOM) significantly contributes to membrane fouling in ultrafiltration (UF) systems, which limits their broader use in municipal wastewater recycle. A modified ceramic ultrafiltration membrane (MCUM) was synthesized via vacuum filtration and thermal treatment and then activated under ultraviolet (UV) irradiation. The results indicated that the MCUM-2.88 exhibited the most excellent removal of EfOM, effectively retained high molecular weight (MW) proteinaceous substances, and converted medium MW humic-like compounds into lower MW derivatives. Through parallel factor analysis in conjunction with the self-organizing map algorithm, it was observed that the MCUM primarily degraded aromatic, high MW fluorescent components, while tryptophan-like substances remained as dominant residues due to their resistance to photodegradation. Additionally, the improved surface roughness and hydrophilicity of the MCUM facilitated fouling mitigation by strengthening interfacial repulsion, which diminished foulant adhesion. The fouling mechanism transitioned from complete and intermediate blocking to predominantly intermediate blocking, accompanied by a reduction in gel layer fouling. Consequently, the reversible fouling resistance of the MCUM was reduced by 76.8 %, and the irreversible resistance by 34.3 %, markedly enhancing antifouling performance. The results underscore the effectiveness of MCUM in advanced municipal wastewater treatment, showcasing enhanced antifouling performance and strong potential for sustainable water reuse applications.