Plant stratum corneum inspired high-strength hydrogel coating modified palm skin by freezing and salting out strategy for efficient gravity-driven oil/water separation

Oily wastewater treatment with sustainable, low energy consumption and low cost has attached great significance to aquatic ecosystems, environmental protection and economic demands. Inspired by the plant stratum corneum, a simple, facile and universal strategy for fabrication of green, efficient gravity-driven and brand-new oil/water separation membrane (named FSP-P-PS) was developed by using the freezing and salting out strategy to coat high-strength hydrogel on the palm skin membrane, which could improve the anti-fouling property of palm skin and increase the tensile property by 227 % compared with that of the pretreated palm skin membrane. Additionally, the as-obtained membrane of FSP-P-PS showed superior self-cleaning and superhydrophilic properties. Under the condition of gravity-driven, the FSP-P-PS possessed high permeation flux (1298.7 L m−2 h−1), excellent separation efficiency (99.91 %) and favorable reusability (10 cycles) for oil-in-water emulsion separation. More importantly, such a plant stratum corneum inspired strategy could be extended to modify other biomass material such as wood chips, leaves and so on. We thus envision that this bio-inspired mild and universal approach for high-strength hydrogel coating modification of biomass membrane will be of great potential use for oil–water separation.