Enabling polyketone membrane with underwater superoleophobicity via a hydrogel-based modification for high-efficiency oil-in-water emulsion separation

Membrane separation is regarded as an efficient technology in treating oily wastewater. However, the oil fouling of the membrane is an unavoidable issue during the separation process, which will largely reduce the permeation flux or even destruct membrane structure. While polyketone is a promising membrane material with favorable chemical resistance to be implemented in oil/water separation, its weak hydrophilicity and underwater oleophobicity limit the possibility of high-efficiency separation. In this work, a hydrophilic alginate hydrogel was successfully deposited onto the polyketone membrane through a facile electrostatic attraction force strategy. By optimizing the concentration of the alginate hydrogel, stable underwater superoleophobicity and ultralow oil adhesion of the membrane were obtained. The membrane showed the significantly improved separation efficiency for the rejection of various kinds of oil-in-water emulsions, indicating the effectiveness and durability of the method proposed in this work. It is expected that this modification method may also be applied for the improvement of other membrane materials.