Solar-assisted fast cleanup of heavy oil spills using a photothermal sponge

Rapid cleanup of heavy oil spills is always considered a great challenge because conventional porous oil sorbents cannot efficiently remove them due to the high viscosity of heavy oil (>10³ mPa s). In this work, we take advantage of the photothermal effect to heat heavy oil by using sunlight as the energy source to significantly reduce its viscosity and thus to achieve a fast heavy oil cleanup. A carbon nanotube (CNT) modified polyurethane sponge was fabricated as a photothermal sorbent that exhibited superhydrophobicity and superoleophilicity, as well as outstanding absorption capacity for heavy oil. Thanks to the excellent photothermal effect of CNTs, the modified sponge achieved nearly full sunlight absorption (99%). The resulting solar heating effectively reduced the viscosity of the heavy oil, which enabled the modified sponge to quickly absorb 20 times its own weight of heavy oil under sun illumination. This solar-assisted heavy oil sorbent design is promising for future remediation of viscous oil-spills.