Biodegradable PLA membranes with TiO₂/MWCNTs for UV-assisted self-cleaning and oil-water separation

• 100 % flux recovery after 5 UV-cleaning cycles without chemical reagents. • >99 % oil rejection with stable TOC values well within EPA standards. • Enhanced membrane hydrophilicity, thermal stability, and porosity through TCNT loading. • A biodegradable and recyclable platform that outperforms PVDF in reusability. This study presents a sustainable, self-cleaning membrane system for oily wastewater treatment based on biodegradable polylactic acid (PLA) reinforced with TiO₂-functionalized multi-walled carbon nanotubes (TCNTs). The hybrid membranes were fabricated via nonsolvent-induced phase separation with TCNT loadings of 0–2 wt%. The incorporation of 2 wt% TCNTs into the PLA matrix enhanced water permeability by 89 % and achieved >99 % oil rejection, outperforming unmodified membranes. Notably, the membranes maintained full flux recovery after five UV-assisted cleaning cycles without the use of chemical agents. Total organic carbon (TOC) analysis confirmed treated water remained within EPA standards across all cycles, whereas the pristine PLA membrane exceeded limits by the fifth cycle. Characterization via SEM, EDS, XRD, contact angle, porometry, and TGA demonstrated improved membrane morphology, surface hydrophilicity, and thermal stability. The results highlight the effectiveness of TiO₂/MWCNT nanocomposites in enabling UV-driven self-cleaning and antifouling behavior in PLA membranes. This work offers a scalable and eco-friendly alternative to conventional synthetic polymer membranes, bridging the gap between membrane performance, fouling resistance, and environmental sustainability.