One-pot synthesis of robust superhydrophobic, functionalized graphene/polyurethane sponge for effective continuous oil–water separation

• A one-pot processing technique was used to produce the modified sponge.
• The modified sponge possessed a superhydrophobicity.
• The modified sponge could act as a selective filter to continuously separate the oil.
• The modified sponge had a high oil–water separation efficiency.

Graphene/polyurethane (PU) sponges with superhydrophobicity have been one-pot synthesized by solvothermal technique. The surfaces of interconnected pores within the PU sponges were modified with (3-Mercaptopropyl)trimethoxysilane and graphite oxide via a solvothermal treatment, allowing crater-like functionalized graphene layers to be formed as a substructure and attached firmly to the polyurethane skeleton. By forming such characteristic nano–micro substructures on the backbones of PU sponges, the graphene/PU sponges possessed a superhydrophobicity with WCA exceeding 160°. When applied in conjunction with a simple vacuum system, this sponge could act as a selective filter to continuously and effectively separate the oil from water. Because the functionalized PU sponge retained original PU structural integrity, the material was chemically robust and capable of separating oil up to 53,000 times of its own mass with high oil–water separation efficiency (>99.5%). The functionalized PU sponge and integrated oil–water separation system proposed in this study may provide a novel and practical methodology for industrious scale oil–water separation.

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