Superhydrophobic polyurethane sponge for efficient water-oil emulsion separation and rapid solar-assisted highly viscous crude oil adsorption and recovery

Rapid and efficient cleaning of oily wastewater and high viscosity crude oil spills is still a global challenge. Conventional three-dimensional porous adsorbents are ineffective for oil-water separation in harsh environment and are restricted to the low fluidity of high viscosity crude oil at room temperature. Increasing temperature can enormously improve the fluidity of viscous crude oil. Herein, the polydimethylsiloxane (PDMS) /carbon black (CB) -modified polyurethane sponge (PU) were prepared by a simple one-step dip-coating method. PDMS/CB@PU (PCPU) exhibits high adsorption capacity to various oils and organic liquid (28.5-68.7 g/g), strong mechanical properties (500 cycles at 50%), outstanding reusability (100 cycles of adsorption and desorption) and excellent environmental stability due to the special PDMS/CB coating. The maximum surface temperature of PCPU sponge can reach 84.7 ℃ under 1 sunlight irradiation. Therefore, the PCPU sponge can rapidly heat and enhance the fluidity of viscous crude oil, significantly speeding up the viscous oil recovery process with the maximum adsorption capacity of 44.7 g/g. In addition, the PCPU sponge can also combine with the vacuum pump to realize the continuous and rapid repair of viscous oil spills from the seawater surface. In consideration of its simple preparation, cost-effectiveness and high oil absorption ability, this solar-assisted self-heating adsorbent provides a new direction for large-scale cleanup and recycling of viscous crude oil spill on the seawater surface.