Mechanically robust, solar-driven, and degradable lignin-based polyurethane adsorbent for efficient crude oil spill remediation

Rapid cleanup of crude oil spills is a worldwide challenge because heavy oil components (>10(3) mPa.s) are difficult for removal by conventional porous oil sorbents due to their inherent high viscosities. In this work, we took advantage of the photothermal effect by using sunlight as the energy source to heat heavy oil components for significantly reducing their viscosities to achieve a fast crude oil cleanup. A carbon nanotube (CNT) modified lignin-based polyurethane foam was fabricated as a photothermal sorbent that exhibited outstanding adsorption capacity for heavy oil. The modified foam achieved nearly full sunlight absorption (97%) with its surface temperature reaching up to 90.3 degrees C within 500 s owing to the excellent photothermal effect of CNTs. The resulting solar heating effectively reduced the viscosity of the heavy oil, which enabled the modified foam to quickly adsorb more than six times (6.34 +/- 0.27 g/g) of its weight of crude oil within 6 min under one sun illumination (1.00KW/m(2)). Meanwhile, the lignin-based foam adsorbents were degradable in alkaline environments and CNTs can be recovered from the same condition. They could reach a degradation efficiency of 88.03% in 2 mol/L NaOH aqueous solution at 80 degrees C for 10 h, and the degradation rate was as high as 6.25 mg/h. Given the novel structural design, excellent environmental friendliness, rapid oil adsorption rate, and high oil adsorption capacity, this work provides a promising solution for addressing catastrophic large-area viscous crude oil spills.

Automated summary

The study successfully developed a carbon nanotube-modified lignin-based polyurethane foam using the photothermal effect to rapidly clean up viscous crude oil spills.