Cobalt Ferrite-Modified Carbon Nanotubes Enhance Peroxymonosulfate Oxidation to Efficiently Degrade Organic Pollutants and Mitigate Ultrafiltration Membrane Fouling in Secondary Effluent System

The freshwater resource scarcity and emerging contaminants in municipal wastewater pose challenges to the sustainability of wastewater reuse and environmental remediation technologies based on membranes. Herein, we propose a cobalt ferrite-modified carbon nanotube (CoFeCNT) activated peroxymonosulfate (PMS) pretreatment, improving secondary effluent purification and alleviating membrane fouling. Based on the effect of hydroxyl radicals, sulfate radicals, and singlet oxygen, CoFeCNT/PMS efficiently removes various emerging organic contaminants. Moreover, this process exhibits an excellent degradation performance on secondary effluent organic matter (EfOM), such as dissolved organic carbon (38.61%), absorbance at 254 nm (97.25%), and fluorescence intensity (above 80%), reducing the fouling load of membrane influent. CoFeCNT/PMS effectively mitigated the membrane fouling from EfOM, with reversible and irreversible fouling reduced by more than 80%. The membrane fouling mode of CoFeCNT/PMS is between intermediate and standard blocking, and the filtration volume entering the cake layer fouling mode increases compared with membrane filtration alone. The polar acid–base microscopic interactions on the membrane surface dominate the production of the free energy barrier (948.60 × 10–6 mJ), which can effectively slow down the dense fouling layer formation. These findings provide a promising strategy for wastewater remediation and membrane fouling mitigation.