Petrochemical industry generates large amounts of oily wastewater that requires effective treatment methods. Among all, membrane filtration techniques have been receiving more attention, due to easy operation and low energy consumption. One of the issues is that the oily wastewater also contains high level of salinity. Thus, preparation of dual function membrane to be used for purification of saline oily wastewater is an attractive option. Inspired from fish scales, we prepared an underwater superoleophobic membrane using microalgae coated on steel mesh which can also be used in water desalination. In order to fix microalgae biofilm on the surface of steel mesh, PVA polymer and glutaraldehyde as crosslinking reagent was used. The salts can also be removed using microalgae biomass coated on steel mesh by the adsorption process. The prepared membrane demonstrated high efficiency (above 98%) for oil-water separation with the highest water flux of 30225.0 L m− 2 h− 1. Under optimized conditions, algae-based mesh exhibited salt rejection of (98.6 ± 0.5) %. Due to its simplicity, low cost and great performance in both oil-water separation and water desalination, the as-prepared membrane could find broad applications for commercial purposes.

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