Substrate-Independent Cupric Phosphate Nanoflower–Mineralized Superhydrophilic Membranes for Diverse Oil–Water Separation

Developing a sustainable and efficient method or material to clean oily wastewater is a pressing need. Herein, a mussel-inspired mineralization strategy is provided to fabricate a high-performance substrate-independent superhydrophilic coating on diverse membranes to separate various types of oily wastewater. A polydopamine (PDA)/poly(ether imide) (PEI) intermediate layer is introduced via a mussel-guided codeposition technique followed by a mineralization process to create a nanoflower-like Cu3(PO4)2-PDA/PEI coating on a membrane. Because of the nanoflowered structure and strong hydration ability of Cu3(PO4)2, the mineralized membrane exhibits superhydrophilicity/underwater superoleophobicity and outstanding anti-oil-fouling properties for efficiently separating various immiscible oil–water mixtures and surfactant-stabilized oil-in-water emulsions. Additionally, the mineralized membrane shows high thermal stability and excellent salt tolerance. The exceptional resistance of the mineralized membrane to oil fouling and its high separation capacity and broad applicability give rise to the tremendous potential of the membrane for practical use in the purification of oily wastewater.