Thiolated graphene-based superhydrophobic sponges for oil-water separation

With the environmental pollution deteriorating, oil-water separation has attracted much attention in recent years. In this work, a facile method is proposed to fabricate superhydrophobic polyurethane sponge for oil-water separation via a simple dipping-drying process. It is based on the utilization of hydrophobic thiolated graphene (GSH) with the water contact angle (WCA) of 128° from graphene oxide through thiolation reaction. The WCAs of the as-prepared sponges were largely determined by the loading of GSH, and the WCAs reached 157.0° and 160.5° with GSH loadings at 5.0% and 7.5%, respectively. The GSH-based superhydrophobic sponge exhibited high absorption selectivity for different organic solvents and oils, the absorption capacity for chloroform attained 90 times and there was no decrease after 10 absorption cycles. Importantly, with the oil-water separation device composed of pump, rubber tubes and GSH-based sponge, the separation efficiency of toluene from water reached 99.7%, and still maintained 99.5% after 5 cycles. Additionally, GSH-based sponge also effectively shortened burning time and reduced black smoke in the combustion process, demonstrating good flame retardancy. Our findings provided a new strategy to fabricate superhydrophobic materials for oil-water separation, showing the great potential in large-scale practical application.