State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing100029, P. R. China.
WestCHEM, School of Chemistry, University of Glasgow, GlasgowG12 8QQ, U.K.
ACS Appl Mater Interfaces. 2023 Jan 25;15(3):4755-4763. doi: 10.1021/acsami.2c19015. Epub 2023 Jan 11.
Efficient separation of water-in-oil emulsion is of great importance but remains highly challenging since such emulsion contains stable tiny droplets with a diameter less than 20 μm. Herein, we reported the fabrication of a modular fibrous functional membrane using an "in situ growth and covalent functionalization" strategy. The as-prepared PAN@LDH@OTS (PAN = polyacrylonitrile; LDH = layered double hydroxides; and OTS = octadecyltrichlorosilane) membrane possessed an interlaced rough nanostructured surface with intriguing superhydrophobic/superlipophilic properties. When applied for the separation of surfactant-stabilized water-in-oil emulsion (SSE), the PAN@LDH@OTS membrane exhibited an ultrahigh permeation flux of up to 4.63 × 10 L m h with an outstanding separation efficiency of >99.92%, outperforming most of the state-of-the-art membranes. In addition, the membrane can maintain a stable permeation flux and superhydrophobic/superlipophilic properties after 20 times of use. Detailed characterization demonstrated that the demulsification of the SSE process was as follows: first, the droplets can be easily adsorbed to the PAN@LDH@OTS membrane due to the improved intermolecular interactions between OTS and the surfactants (Span 80); second, the droplets can be deformed by the electropositive LDH laminate; and third, the deformed tiny emulsion droplets coalesced into large droplets and floated up, and as a result, efficient separation of SSE can be achieved.
高效分离水包油乳液具有重要意义，但由于乳液中含有直径小于 20μm 的稳定微小液滴，因此仍然极具挑战性。在此，我们报告了一种使用“原位生长和共价功能化”策略制备模块化纤维功能膜的方法。所制备的 PAN@LDH@OTS（PAN=聚丙烯腈；LDH=层状双氢氧化物；OTS=十八烷基三氯硅烷）膜具有交错的粗糙纳米结构表面，具有有趣的超疏水/超亲油特性。当应用于分离表面活性剂稳定的水包油乳液（SSE）时，PAN@LDH@OTS 膜表现出高达 4.63×10 L m h 的超高渗透通量和超过 99.92%的出色分离效率，优于大多数最先进的膜。此外，该膜在使用 20 次后仍能保持稳定的渗透通量和超疏水/超亲油性能。详细的表征表明，SSE 过程的破乳如下：首先，由于 OTS 与表面活性剂（Span 80）之间改善的分子间相互作用，液滴很容易被 PAN@LDH@OTS 膜吸附；其次，带正电的 LDH 层压物可以使液滴变形；第三，变形的微小乳液液滴聚结成大液滴并浮起，从而可以实现 SSE 的有效分离。
