Recent advances in membrane hydrophilic modification with plant polyphenol‐inspired coatings for enhanced oily emulsion separation

Abstract Oily wastewater, especially the emulsified one, causes serious environment pollution and poses threats to the ecosystem and resource recycling. Among various filtration media, porous polymeric membranes have gained tremendous attention in dealing with oily emulsions due to their energy‐saving, cost‐effective, and highly efficient features. However, to alleviate membrane fouling by oil droplets and ensure high separation efficiency, endowing membrane with superhydrophilicity and underwater superoleophobicity via facile strategy is highly desired. Taking advantages of the mild forming conditions, universality and cost‐efficiency, more and more efforts have been devoted to membrane hydrophilic modification by plant polyphenol‐inspired coatings in recent years. In this review, we focus on recent advances in constructing plant polyphenol‐involved coatings on membrane surface for oil‐in‐water emulsion separation. The interactions between plant polyphenol and functional materials including amino‐functionalized materials, transition metal ions and oxidants via covalent chemistry, coordination chemistry, and rapid oxidation are highlighted. In addition, the impacts of the resultant coating on the wettability, oily emulsion separation performance, and anti‐oil fouling performance of the modified membrane are systematically summarized. Finally, future outlooks in membrane surface engineering with plant polyphenol‐involved coatings are discussed to further broaden the research related to high‐efficiency oil/water separation based on membrane technology.