PVDF Membranes Incorporating OPEFB-Derived Cellulose for Enhanced Synthetic Dye Removal and Thermoresponsive Cleaning Performance

This study developed thermoresponsive poly(vinylidene fluoride) (PVDF) membranes incorporating oil palm empty fruit bunch (OPEFB)-derived cellulose and SiO2–poly(N-isopropylacrylamide) (SiO2–PNIPAM) particles for methylene blue (MB) removal and thermally assisted cleaning. Membranes were fabricated via non-solvent-induced phase separation and characterized in terms of morphology, porosity, pore size, hydrophilicity, permeability, antifouling behaviour, and dye rejection. The incorporation of OPEFB-derived cellulose and SiO2–PNIPAM particles significantly altered membrane structure and surface properties. The combined membrane (PVDF-CP) containing OPEFB-derived cellulose and SiO2–PNIPAM exhibited the highest porosity (50.09 ± 1.26%), smallest mean pore size (16.29 ± 0.45 nm), and lowest water contact angle (63.66 ± 4.73°). Although the cellulose-modified membrane showed the highest pure water permeability (66.29 ± 2.21 L m−2 h−1 bar−1), PVDF-CP achieved the highest MB rejection of 76.99% and 83.60% before and after cleaning, respectively, together with a flux recovery ratio (FRR) of approximately 97%. The SiO2–PNIPAM particles modified membrane exhibited the highest FRR (122%) owing to the thermoresponsive behaviour of PNIPAM. The results demonstrate that the combined incorporation of OPEFB-derived cellulose and SiO2-PNIPAM particles enhanced membrane hydrophilicity, fouling resistance, cleaning efficiency, and dye removal performance. These findings highlight the potential of sustainable biomass-assisted thermoresponsive membranes for wastewater treatment applications.