Strengthening nanofiltration membrane: Strategies for enhanced antifouling performance

Abstract

Nanofiltration (NF) membranes, characterized by intermediate pore sizes and operating pressures between ultrafiltration and reverse osmosis, are increasingly gaining attention for applications in water treatment and ion/molecule separation. However, membrane fouling remains a significant challenge, impacting membrane performance and longevity. In this review, we first provide an overview of the characteristics of fouling occurrence, fouling types, and cleaning methods for NF membranes, with a focus on the demands these behaviors impose on membrane properties and materials during the development of antifouling membranes. Next, we summarize recent advances in the fabrication methods of antifouling NF membranes, highlighting techniques such as interfacial polymerization (IP), surface grafting, surface coating, and layer-by-layer self-assembly. Due to the scalability, customization potential, and broad applicability, IP is considered the most promising method for fabricating antifouling NF membranes. Third, the strategies for enhancing the antifouling performance of NF membranes prepared by IP are discussed in terms of regulating the membrane surface properties, spatial structure, and material chemistry, and the challenges that still need to be faced by each strategy are pointed out. Subsequently, recent advances in process-oriented antifouling enhancement for NF membranes are reviewed. Finally, we conclude that with advancements in fabrication methods and material science, further improvements in the preparation and application of antifouling NF membranes are highly promising. This review provides direction and guidance for the further development and industrialization of antifouling NF membrane technologies.