Low-pressure membrane filtrations are considered as effective technologies for sustainable oil/water separation. However, conventional membranes usually suffer from severe pore clogging and surface fouling, and thus, novel membranes with superior wettability and antifouling features are urgently required. Herein, we report a facile green approach for the development of an underwater superoleophobic microfiltration membrane via one-step oxidant-induced ultrafast co-deposition of naturally available catechol/chitosan on a porous polyvinylidene fluoride (PVDF) substrate. Membrane morphology and surface chemistry were studied using a series of characterization techniques. The as-prepared membrane retained the original pore structure due to the ultrathin and uniform catechol/chitosan coating. It exhibited ultrahigh pure water permeability and robust chemical stability under harsh pH conditions. Moreover, the catechol/chitosan hydrophilic coating on the membrane surface acting as an energetic barrier for oil droplets could minimize oil adhesion on the surface, which endowed the membrane with remarkable antifouling property and reusability in a cyclic oil-in-water (O/W) emulsion separation. The modified membrane exhibited a competitive flux of ~428 L/(m²·h·bar) after three filtration cycles, which was 70% higher than that of the pristine PVDF membrane. These results suggest that the novel underwatersuperoleophobic membrane can potentially be used for sustainable O/W emulsions separation, and the proposed green facile modification approach can also be applied to other water-remediation materials considering its low cost and simplicity.

低压膜过滤被认为是实现可持续油水分离的有效技术。然而，常规膜通常遭受严重的孔堵塞和表面结垢，因此，迫切需要具有优异的润湿性和防污特征的新型膜。在这里，我们报告了一种简便的绿色方法，用于通过在多孔聚偏二氟乙烯（PVDF）基材上自然地利用邻苯二酚/壳聚糖的一步一步氧化剂诱导的超快共沉积来诱导水下超疏油微滤膜的发展。使用一系列表征技术研究了膜的形态和表面化学。由于超薄且均匀的邻苯二酚/壳聚糖涂层，所制备的膜保留了原始的孔结构。在苛刻的pH条件下，它具有超高的纯水渗透性和强大的化学稳定性。此外，膜表面的儿茶酚/壳聚糖亲水涂层可作为油滴的能量屏障，可最大程度地减少油在表面上的附着力，从而使膜具有出色的防污性能和在循环水包油（O / W）中的可重复使用性）乳液分离。改性膜的竞争通量约为428 L /（m² ·H·3个过滤周期，其比原始PVDF膜的高70％后巴）。这些结果表明，该新型水下超疏油膜可潜在地用于可持续的O / W乳液分离，并且考虑到其低成本和简单性，所提出的绿色简便改性方法也可应用于其他水修复材料。