Waste paper derived cellulose acetate enhances antifouling performance of polyethersulfone membranes

The increasing accumulation of paper waste creates an opportunity to recover cellulose-rich resources for value-added membrane materials, while polyethersulfone (PES) membranes remain limited by hydrophobicity-induced fouling. In this study, cellulose acetate (CA) synthesized from waste paper was used as a sustainable hydrophilic additive for PES ultrafiltration membranes fabricated by phase inversion. The novelty of this study lies in the direct valorization of waste paper into CA as a functional PES-membrane additive, thereby linking solid-waste utilization with membrane antifouling enhancement within a circular-material framework. CA incorporation decreased the water contact angle from approximately 83° for pristine PES to approximately 61–62° for the highest CA loading and produced a more open porous morphology. FTIR analysis showed the characteristic CA carbonyl band and spectral changes consistent with intermolecular interactions between CA and PES. The highest pure-water flux was approximately 252 L m⁻² h⁻¹, while the flux recovery ratio increased from approximately 61% to 89% during BSA fouling tests. At higher CA loading, tensile strength decreased from approximately 142.2 MPa for pristine PES to 107.9 MPa for M3, indicating a trade-off between structural openness and mechanical strength. Overall, waste-paper-derived CA improved membrane hydrophilicity, permeability, and fouling resistance and provides a proof-of-concept route for integrating paper-waste valorization with PES membrane engineering.