Super-hydrophobic graphene-coated thermoplastic polyurethane porous monolith with superior photothermal effect for solar-assisted efficient cleanup of crude oil spill

Abstract

Frequent occurrences of oil spill accidents have posed a serious threat to ecological system and human health, hence it is imperative to explore new-typed absorbent materials to efficiently clean up high-viscosity crude oil in an environmentally-friendly way. Herein we reported a reduced graphene oxide-wrapped and fluoroalkylsilane-modified thermoplastic polyurethane porous monolith (abbr. F-rGO@TPU monolith) with superior photothermal effect for solar-driven high-efficiency cleanup of crude oil spill. Owing to superior superhydrophobicity (water contact angle of 153°) and porosity (87.4 %), the as-prepared F-rGO@TPU monolith possessed high saturated absorption capacity (6.5–53.7 g/g) and splendid oil/water separation efficiency (over 99.3 %) for various low-viscosity oils/organic solvents. Excellent reversible compressibility and fatigue resistance (1000 compression cycles under 80 % strain) allowed the monolith to repetitively absorb oil via simple manual squeezing. By virtue of the outstanding photothermal effect of reduced graphene oxide coating, the F-rGO@TPU monolith exhibited almost full absorption (96.0 %) of solar spectrum (wavelength range of 250–2500 nm) and efficient light-to-heat conversion capability (achieving 80 °C in 5 min under 1.0 kW/m2 solar irradiation), enabling it to in situ reduce the viscosity of crude oil for rapid absorption. More importantly, the solar-heated monolith could continuously and fast separate crude oil/water mixture by a pump-assisted absorption device (crude oil flux of 510 kg/(m2·h)), revealing immense potential in oil spill remediation.