Magnetically driven superhydrophobic/superoleophilic graphene-based polyurethane sponge for highly efficient oil/water separation and demulsification

Cost-effective and efficient sorbents with emulsion-breaking capability, especially surfactant-stabilized emulsions, are required to remediate oil spills from water. Herein, in situ growth of magnetic Mn0.01Co0.90Fe3O4 (MCFO) nanoparticles (NPs) on reduced graphene oxide (RGO) was performed to prepare MCFO/RGO nanocomposite via a simple solvothermal method. The nanocomposite was coated onto a polyurethane (PU) sponge to fabricate a novel magnetic, superhydrophobic/superoleophilic and flame-retardant material. The prepared magnetic MCFO/RGO/PU was superhydrophobic with a contact angle of 165 +/- 1 degrees. Compared with neat PU, the MCFO/RGO/PU sponge could be driven by a magnet for oil collection in water. More importantly, the MCFO/ RGO/PU sponge could effectively collect oil droplets from surfactant-free and stabilized toluene/water emulsions. In addition, the fabricated sponge exhibited excellent performance for oils and organic solvents sorption, achieving up to 131 times of its own weight and retaining its ability even after 10 sorption cycles. Interestingly, the thermal stability and fire retardancy of the prepared PU sponge were improved with respect to neat PU.