Aminated lignin-modified polyethersulfone membranes with enhanced antifouling performance for oil-water separation

Polyethersulfone (PES) membranes are widely utilized in oil-water separation applications owing to their exceptional chemical and thermal stability. However, their inherent hydrophobic nature renders them susceptible to fouling and blockage by oily substances in practical applications. In this study, aminated lignin (AML), containing hydrophilic amino groups and exhibiting good compatibility with PES, was incorporated into PES membranes to prepare AML/PES composite membranes. The physical and chemical properties, oil-water separation capacity, and anti-fouling performance of the composite membranes were systematically analyzed. Under optimal process conditions (AML concentration 2.0 wt%, PES concentration 16 wt%, temperature 40 °C), the AML/PES membrane exhibited markedly improved performance; the porosity reached 75.67 % and the hydrophilic contact angle decreased to 53.4°. Furthermore, pure water flux recovery rate FRR significantly increased from 65.51 % without AML to 79.22 %, while the resistance to irreversible contamination decreased to 26.47 %, and the resistance to reversible contamination increased to 29.75 %. After three testing cycles, the recovery rate of pure water flux declined by only 9.38 %, indicating that the composite membrane has excellent anti-pollution performance and good cycling stability. Our results highlight a promising strategy for the high-value utilization of lignin, providing a new type of high-performance membrane material solution for the field of oily wastewater treatment.