Lignin/CaCO₃ Coated Membrane Integrated with UV Deactivation for Water Filtration and Pathogen Removal

The integration of lignin-coated membranes and ultraviolet (UV) inactivation provides an effective approach for enhanced water filtration and pathogen removal. In this study, a hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membrane was coated with lignin and calcium carbonate nanoparticles to improve hydrophilicity and antifouling properties. The modified membrane demonstrated significantly enhanced performance, achieving an oil emulsion rejection rate of 95.97% and a flux of 63.87 L·m⁻²·h⁻¹, which was approximately twice that of the unmodified PVDF membrane. Additionally, calcium carbonate nanoparticles further improved the oil removal efficiency. To complement membrane filtration, UV treatment was employed for pathogen deactivation, targeting the nucleic acids of waterborne pathogens to inhibit their replication. The UV-treated water was evaluated in term of bacterial regrowth, revealing distinct differences between bacterial species. Escherichia coli exhibited higher photoreactivation rates (10.66%) under fluorescent light compared to dark conditions, whereas total coliforms showed even greater photoreactivation susceptibility (21%) under the same UV dosage (237 mJ/cm²). The integrated membrane-UV filtration system effectively eliminated up to 95% of E. coli from river water and significantly reduced turbidity. These findings highlight the potential of calcium carbonate-enhanced lignin coatings for membrane modification and underline the importance of understanding bacterial responses to UV disinfection in integrated water treatment systems.