Hierarchical superhydrophobic polydimethylsiloxane/copper terephthalate/polyurethane sponge for highly efficient oil/water separation

Frequent discharge of oily wastewater in industry or daily life not only seriously wastes oil resources, but even endangers environment. Functional sponge material is an ideal adsorbent for treating and recycling oily wastewater owing to their low cost and high efficiency. In order to improve the treatment effectively of oily wastewater, the commercial polyurethane sponge (PU) was modified by copper terephthalate (CuTPA) and polydimethylsiloxane (PDMS), and a robust composite sponge with hierarchical structure was prepared. The composite sponge possesses many superior properties, including good superhydrophobicity (water contact angle was 157°), porous network structure and stable mechanical properties, which makes it has good oil adsorption capacity (10–33 g/g) and cycling performance. More importantly, the hierarchical structure of the composite sponge improves the wettability of the sponge and the separation efficiency of oil-in-water emulsion (above 92%). In addition, the composite sponge also has excellent chemical stability and high-temperature resistance, which indicates that the composite sponge has a good application prospect in the field of oil/water separation.