Durable superhydrophobic sponge for all-weather cleanup of viscous crude oil by electrothermal and photothermal effects

Creating innovative absorbent materials with a rapid absorption rate and high absorption efficiency for viscous crude oils continues to be a global problem. Hydrophobic/oleophilic porous sorbents with light-to-heat or electric-to-heat capabilities are attractive options for crude oil clean-up, but their complicated preparation processes, poor stability, and variable weather restrict their practical usage. Herein, the light-absorbing and electrical polypyrrole and Fe3O4 are introduced to endow the melamine sponge with excellent photothermal and electrothermal properties, while the polydimethylsiloxane is coated on the surface of the sponge to make it durable, compressible, and superhydrophobic. Thanks to the superior photo/electro-heat conversion capability, the temperature of the as-prepared sponge′s surface may reach 95.9 °C under solar light with 1 kW m−2 intensity or 101.4 °C under a voltage of 11 V, making it adaptable to reduce the crude oil's viscosity and absorb it in all weather. In addition, when the sponge is exposed to sunlight and voltage at the same time, its crude oil absorption velocity is dramatically improved and is about 107 times greater than that of an unheated sponge. Based on the eco-friendly preparation method and excellent crude oil absorption performance, this work provides a promising absorbent for the recycling of spilled crude oil.