Demulsification and antifouling strategies for superhydrophilic oil-water emulsion separation materials: A review

Abstract

Efficient separation of oil-water emulsions remains a critical challenge in industrial wastewater treatment, oily water purification, and marine oil spill recovery. Superhydrophilic separation materials, with their high separation efficiency, low energy consumption, and absence of secondary pollution, have emerged as an ideal solution. Within these materials, demulsification and anti-fouling strategies are central to achieving efficient emulsion separation. However, solely enhancing demulsification capability enables high-efficiency separation in the short term, yet insufficient anti-fouling capacity leads to fouling, causing sudden flux decline. Conversely, merely improving anti-fouling ability can maintain stable flux, but inadequate demulsification results in low separation efficiency. Therefore, synergistically enhancing both demulsification and anti-fouling is crucial to achieving stable and long-lasting separation. Despite extensive recent progress, comprehensive reviews integrating demulsification and anti-fouling remains relatively scarce. This review aims to address this urgent need, focusing specifically on membrane-type superhydrophilic materials. It provides an in-depth analysis of the advances in their demulsification and anti-fouling strategies. First, it introduces the fundamental mechanisms governing surface wettability regulation. Subsequently, from a performance perspective, it outlines the key factors and parameters influencing separation effectiveness. Building upon a comprehensive summary of recent strategies for enhancing demulsification and anti-fouling capabilities and their underlying mechanisms, this review objectively analyzes the prevalent challenges and limitations of current approaches. Finally, it provides valuable guidance for the future design and optimization of advanced oil-water separation materials.