Poly(Sulfuric Ester) Copolymer‐Based Ultrafiltration Membranes for Surface Water Treatment: Structure, Separation Performance, and Antifouling Properties

ABSTRACT Regulating polymer matrix composition is an effective yet underexplored strategy for enhancing the performance of ultrafiltration membranes. In this study, poly(sulfuric ester) copolymer (PSFEc) was employed as the membrane matrix material, and a series of ultrafiltration membranes with PSFEc contents ranging from 15 to 18 wt% were fabricated via non‐solvent induced phase separation. The effects of PSFEc content on membrane morphology, surface properties, separation performance, and antifouling behavior were systematically investigated. The results reveal that increasing PSFEc content induces pronounced changes in membrane microstructure and surface characteristics, leading to simultaneous enhancement of humic acid rejection and antifouling performance. The optimized PSFEc‐18 membrane achieved a high humic acid rejection of 89.6% and a flux recovery ratio of 85.3%. Furthermore, during practical surface water filtration tests, the PSFEc‐18 membrane exhibited effective turbidity removal of 72.7% and maintained stable filtration performance over multiple operation cycles. Compared with previously reported ultrafiltration membranes, the PSFEc‐18 membrane demonstrates a favorable balance between water permeance and antifouling capability. This study provides fundamental insights into the structure–property–performance relationships of polymer‐based ultrafiltration membranes and offers a simple and effective strategy for designing high‐performance membranes through regulation of membrane matrix content, with potential implications for sustainable water treatment applications.