All-Lignocellulosic Superhydrophobic Wood Sponge for Oil–Water Separation

Oil spills, sewage discharge, and organic solvent leakage pose serious threats to ecosystems and resource sustainability. However, most oil-absorbing sponges rely on costly modifications or nonrenewable petroleum-based raw materials. Here, we develop an all-lignocellulosic superhydrophobic wood sponge by integrating lignin nanospheres into a wood scaffold via liquid-phase deposition and stabilizing them with poly(dimethylsiloxane), achieving a low-cost and sustainable platform for oil–water separation. The obtained wood sponge combines superhydrophobicity, and high porosity, featuring a high water contact angle of 153.28° and exceptional coating robustness against extreme pH (2–12), wide temperature ranges (20–170 °C), and prolonged fluid impact (18 h), showing near-complete stress recovery at 30–50% strain and maintaining structural integrity over 150 compression cycles at 40% strain without plastic deformation. When the wood sponge was used for oil–water separation, it exhibited efficient oil adsorption above and below water with a high capacity of 6534.24 mg g –1 and sustained separation efficiencies of ∼89% (submerged) and ∼95% (exposed) over 10 cycles, alongside stable adsorption over 20 cycles. Simultaneously, the incorporation of lignin nanospheres imparts excellent photothermal performance to the superhydrophobic sponge, rapidly reaching 70.8 °C within 5 min under 1.5 kW m –2 irradiation and maintaining stable efficiency over 10 cycles, thereby boosting the adsorption rate of viscous reagents by about 4.0 times under illumination. The superhydrophobic wood sponge provides a promising and practical candidate for offshore crude oil spill remediation.