Electrospinning janus membranes for on‐demand oil/water collection and emulsion separation

Abstract Oily water pollution has become one of the most serious water environment issue in worldwide. Membrane that can effectively and efficiently remove different oil pollutions from the complex water environment is still urgently needed. Herein, a Janus membrane with opposite wettability that can separate heavy oil–water and light oil–water mixtures on demand was prepared by using a simple sequential electrospinning and chemical crosslinking method. The membrane could remove oil or water under gravity with a high oil/water flux and excellent separation efficiency. Moreover, the membrane could separate different kinds of oil‐in‐water emulsions under gravity with a high flux of 1184 L m −2 h −1 and a tiny flux loss of 4.4% after a 10‐cycle separation. Owing to its excellent anti‐pollution properties the flux recovery rate of the membrane was still higher than 80% after 150 min of emulsion separation. Additionally, the membrane also displayed the ability to transport liquid unidirectionally, giving whom the capabilities to collect oil underwater or water underoil. This research provides a novel and simple method for producing membranes for a variety of separation applications.