Superhydrophobic polyurethane sponge based on sepiolite for efficient oil/water separation

Massive oil leakage accidents and illegal discharge of oily wastewater have not just destroyed the sustainability of the ecological environment but caused permanent damage to marine ecosystems, which makes it urgent to handle it. In this paper, by means of sol-gel, micro-nan silica that grew from the surface of fibrous sepiolite was organically modified with 1 H, 1 H, 2 H, 2 H-perfluorodecyltriethoxysilane (PFDS). The superhydrophobic sepiolite/silica firmly attached to the surface of polyurethane sponge under the action of oily epoxy resin with strong adhesion. The sponge exhibited superhydrophobicity and excellent selective oil adsorption capacity (19.98–40 times of their own weight). More importantly, besides the effective separation of immiscible oil-water mixtures (the separation rate reached 98.72%), it could also efficiently separate oil with water and oil with salt solution emulsions. In addition, the sponges kept hydrophobic even after floating in extremely corrosive liquids for 20 h, showing a strong resistance to strong acidic as well as alkaline liquids. After 100 times of mechanical compression, the three-dimensional structure of sponge held still and the water contact angle was greater than 144°, demonstrating an excellent mechanical stability, which provided a reference for its practical application in oil-water separation.