Superhydrophilic membranes with simultaneous underwater superoleophobicity are highly desirable and worth exploring for separation of emulsified oil from water. In this work, combining the strong negative charges of phytic acid (PA) and the high cationic charge density of polyethyleneimine (PEI), an eco-friendly PA@PEI polyelectrolyte complex was synthetized in aqueous solution. And then the polyelectrolyte complex was deposited onto hydrophobic PVDF membranes through a one-step assembly approach with high convenience, endowing the membranes with superhydrophilic and underwater superoleophobic property. The as-prepared PA@PEI/PVDF membrane shows outstanding static and dynamic water stability, and was successfully used to separate multiple oil-in-water emulsions, with an average rejection rate exceeding 98.5% and a water flux up to 12203.6 L m⁻²∙h⁻¹∙bar⁻¹. Furthermore, the water flux can be recovered to a high level after four separation-washing cycles, showing excellent antifouling performance and recovery capability. Together with its natural raw materials and environmentally friendly preparation strategy, the PA@PEI/PVDF membrane shows great potential in practical treatment of emulsified oily wastewater.

同时具有水下超疏油性的超亲水膜是非常需要的，值得探讨从水中分离乳化油的方法。在这项工作中，结合了植酸（PA）的强负电荷和聚乙烯亚胺（PEI）的高阳离子电荷密度，在水溶液中合成了一种环保型PA @ PEI聚电解质复合物。然后将聚电解质复合物通过一步组装的方法高度方便地沉积在疏水性PVDF膜上，赋予膜超亲水性和水下超疏油性。制备的PA @ PEI / PVDF膜具有出色的静态和动态水稳定性，并已成功用于分离多种水包油乳液，平均截留率超过98.5％，水通量高达12203.6 L m⁻² ∙h ^-1 ∙bar ^-1。此外，在四个分离洗涤循环之后，水通量可以被回收到高水平，显示出优异的防污性能和回收能力。结合其天然原料和环保的制备策略，PA @ PEI / PVDF膜在乳化含油废水的实际处理中显示出巨大潜力。