Compressive, ultralight and fire-resistant lignin-modified graphene aerogels as recyclable absorbents for oil and organic solvents

Compressive, ultralight and fire-resistant graphene aerogel is facilely modified by renewable lignin biomass with hydrophobic and porous skeletons. The lignin-modified graphene aerogel (LGA) show highly efficient absorption of not only petroleum oils, but also toxic solvents such as toluene, chloroform and carbon tetrachloride (up to 350 times of its own weight), which is superior to that of graphene aerogel (GA) and among the highest in previous reported absorbents. Even after several compressive and release cycles, their absorption capacity are also maintained at 96%. Moreover, the absorption capacity can be further improved by carbonation treatment maximum up to 522 times of its own weight. Importantly, the LGA can be regenerated by repeated heat treatment and squeezing method, yielding almost full release of adsorbates. Such a high efficient, recyclable and renewable LGA exhibits it a potential candidate for applications in oil-water separation and also paves way to high-valued utilization of biomass waste.