Reusable, Stable, Efficient and Multifunctional Superhydrophobic and Oleophilic Polyurethane Sponge for Oil–Water Separation Prepared Using Discarded Composite Insulator

Oil spills and chemical leakages are a serious source of pollution in oceans and rivers, and have attracted worldwide attention. Many scientists are currently engaged in the development of oil–water separation technology. In this study, the umbrella skirt of a discarded silicone rubber insulator was utilized as feedstock, and polydimethylsiloxane (PDMS) was employed to immobilize the prepared powder (FXBW) onto a polyurethane (PU) sponge skeleton. Without any modifications using chemical reagents, a novel oil–water separation material, FXBW-PU, was developed, with a water contact angle of 155.3°. The FXBW-PU sponge exhibited an absorption capacity ranging from 11.79 to 26.59 g/g for various oils and organic solvents, while maintaining an excellent selective adsorption performance, even after undergoing ten compression cycles, due to its exceptional chemical and mechanical stability. With the assistance of a vacuum pump, the FXBW-PU sponge was utilized in a continuous separation apparatus, resulting in a separation efficiency exceeding 98.6% for various oils and organic solvents. The separation efficiency of n-hexane remains as high as 99.2% even after 10 consecutive separation cycles. Notably, the FXBW-PU sponge also separated the dichloromethane-in-water emulsions, which achieved the effect of purifying water. In summary, FXBW-PU sponge has great potential in the field of cleaning up oil/organic solvent contamination due to its low preparation cost, environmental friendliness and excellent performance.