Magnetic polyurethane sponge for efficient oil adsorption and separation of oil from oil-in-water emulsions

In this contribution, we report a straightforward method for the preparation of magnetic polyurethane (MPU) sponge with superhydrophobic/superoleophilic properties. The MPU sponge is fabricated in a two-step process consisting of surface functionalization of PU sponge with 3,5-bis(trifluoromethyl)benzenediazonium tosylate [ADT-(CF3)(2)] for the enhancement of its hydrophobicity, followed by incorporation of magnetic nanoparticles modified with the same diazonium salt. The proposed functionalization scheme endows the PU sponge with superhydrophobic and magnetic properties necessary for efficient oil-in-water emulsion separation and easy recovery through the application of an external magnet. The MPU sponge exhibits high adsorption capacity (40 to 75 wt/wt) for various oils such as rapeseed and pump oils, and organic solvents. Additionally, the MPU sponge is successfully applied for the effective separation of oil-in-water emulsions. Taken together, the results obtained in this work hold promise for many environmental applications.