High-flux and durable Janus membrane for oil-in-water emulsions separation via asymmetric acylated zein nanoparticle assembly

The treatment of emulsion-based oily wastewater presents significant challenges due to the scarcity of effective separation materials and the risk of secondary pollution. Janus membranes, with their asymmetric wettability, have emerged as a promising solution for efficiently separating oil-water mixtures. In this study, we developed an excellent environmental friendliness Janus membrane by assembling asymmetric acylation-modified zein nanoparticles (AAZN) and adsorbing them onto one side of polyvinylidene fluoride (PVDF) channels through evaporation-induced self-assembly. The adsorption of AAZN within the membrane pore channels reduced the thickness of the hydrophobic layer to 50-64 mu m, facilitating droplet contact with the hydrophilic layer and accelerating the generation of capillary forces. As a result, the Janus membrane demonstrated an ultra-high flux of 20,524.47 Lm- 2 h- 1 bar- 1 and outstanding separation efficiency (>= 97.91 %) in treating oil-in-water emulsions. Remarkably, the membrane maintained consistent performance over 26 reuse cycles, with flux values consistently around 20,000 Lm- 2 h- 1 bar- 1. Furthermore, molecular dynamics (MD) simulations revealed that the Janus channels exerted significant and opposing forces on water and oil molecules within the emulsion droplets, contributing to exceptional emulsion-breaking and separation capabilities. This study presents a green, straightforward, and efficient approach for the fabrication of Janus membranes, offering promising prospects for the production of environmentally friendly oil-water separation membranes.