High capillary effect and solar dual-drive nanofibrillated cellulose aerogels for efficient crude oil spill cleanup

• Wood-inspired strategy for constructing aerogel with directional structure is proposed. • Crude oil cleanup is rapidly driven by the capillary effect and solar energy. • Excellent self-absorption rate and capacity for highly viscous oil are achieved. • D-CuS@CP-PMTS aerogel exhibits superior reusability, durability, and universality. Frequent oil spills pose a serious threat to ecosystems, and rapid cleanup and recycling of oil spills are in high demand. Herein, inspired by natural wood structures and solar-driven viscosity-break, we developed a rapid oil-adsorption aerogel named D-CuS@CP-PMTS, which is dual-driven by capillary effect and solar energy. Briefly, copper sulfide (CuS) nanoparticles were rapidly in situ deposited on the template of oxidized nanofibrillated cellulose (ONC), aiming at achieving high photothermal effects. Subsequently, ethylene glycol diglycidyl ether (EGDE) was introduced to build multiple cross-links between CuS@ONC and polyvinyl alcohol (PVA), followed by fabricating an aerogel with directional channels for rapid oil transport using unidirectional freeze-drying technology. Finally, methyltrichlorosilane (MTS) was uniformly deposited on the aerogel using a gas–solid reaction to improve its hydrophobicity. The resulting composite aerogel achieved rapid oil adsorption with the dual assistance of solar self-heating and oriented channel structure, which significantly shortened the oil adsorption time (from 45 min to 2 min), companying with encouraging antibacterial effects. Meanwhile, rapid and repeated multiple adsorptions of high-viscosity crude oils and high melting point oils were achieved, which is superior to other reports. This work provides a new insight into adsorption and recycling of high-viscosity crude oil, and also broadens the potential application prospects of ONC-based aerogels.