High strength and ultralight lignin-mediated fire-resistant aerogel for repeated oil/water separation

Oil spillage accidents have caused serious environmental issues, and resulted in oil-cleaning materials receiving widespread attention. In this study, lignin, a crucial recalcitrant component in biomass utilization, was employed to mediate the preparation of graphene aerogel for oil/water separation and rapid regeneration through combustion. The resultant aerogel exhibits ultralight weight (14.22 mg/cm3), high porosity (99.01%), good mechanical properties (1.361 ± 0.04 MPa), super-hydrophobicity (Water Contact Angle = 154.9°), excellent oil and water separation performance (adsorption capacity of chloroform = 102 g/g), and rapid regeneration via direct ignition within 1 min. In addition, the obtained aerogel not only maintained high oil absorption rates in harsh environments (strong acid, strong alkali, high salinity, and high temperature) and facilitated continuous separation of oil and water through pumping but also retained approximately about 90% of the initial absorption capacity after at least 20 combustion cycles. Therefore, based on these extraordinary properties, the obtained aerogel demonstrates great potential for the treatment of marine oil spills. Furthermore, this work may provide a new approach for realizing the high-value utilization of lignin.