Development and performance of chemically treated PVDF hollow fiber membrane under UV post-treatment

This study investigates the effects of ultraviolet (UV) irradiation on the structural, chemical, and performance characteristics of polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs), with and without chemical treatment using hydrogen peroxide (H2O2) or polyethylene glycol (PEG). Membranes were exposed to UV light for 10, 20, and 30 minutes. Characterization techniques including SEM, FTIR, EDS, NMR, and AFM revealed that short-term UV treatment preserved the chemical integrity of the membranes and caused no significant surface damage, especially in chemically pretreated samples. PEG and H2O2 treatments enhanced membrane resistance to UV-induced degradation. Surface hydrophilicity improved with UV exposure, as indicated by reduced water contact angles and increased porosity. The treated membranes exhibited increased permeability 52.6 LMH to 82.3 LMH after 30 minutes of UV exposure, especially in H2O2-modified samples, while maintaining Methylene blue (MB) rejection of 75%. In contrast, PEG-modified membranes showed reduced permeability (from 49.8 LMH to 29.2 LMH) with UV exposure due to partial pore blocking. Mechanical strength varied with treatment, showing slight improvements in H2O2-treated samples and reductions in raw and PEG-treated ones. These findings demonstrate that UV post-treatment, especially when combined with H2O2, provides a clean and effective modification route to enhance PVDF HFMs, leading to improved hydrophilicity, permeability, and stability for water treatment applications.