Ultralight and highly efficient wood carbon aerogel for oil/water separation: recyclable via compression and combustion

Oil spills and organic solvent discharges pose serious ecological and environmental risks, necessitating the development of highly efficient oil/water separation materials. Herein, we designed and prepared a novel ultra-light aerogel, namely hydrophobic reduced graphene oxide/polyvinyl alcohol@carbon delignified wood aerogel (H-rGO/PVA@CDWA), for this purpose. In particular, we integrated a delignified wood aerogel with graphene oxide (GO) and PVA. Subsequent carbonisation at 500 °C and treatment with methyltrichlorosilane yielded a material that could be recycled through combustion or extrusion. The H-rGO/PVA@CDWA retained the anisotropic three-dimensional pore structure of wood, exhibiting good mechanical properties and fire resistance. The material also showed considerable hydrophobicity (water contact angle = 139.42°) and excellent adsorption capacity towards various oils (6.5041–17.8426 g/g). Notably, the material maintained a high adsorption capacity and satisfactory elasticity after 20 extrusion–adsorption cycles and 10 combustion–adsorption cycles. Furthermore, the material exhibited a high oil/water separation efficiency for various emulsions and a considerable capacity for continuous oil/water separation. The material preparation strategy proposed herein has broad application prospects for wood utilisation in oily wastewater treatment, oil pollution remediation and organic solvent recovery. Graphical abstract