Graphene/nanofiber aerogels: Performance regulation towards multiple applications in dye adsorption and oil/water separation

The fabrication of multifunctional graphene-based aerogels is challenging due to the difficulty in controlling the structures and properties to satisfy various demands. Herein, we develop a versatile graphene oxide/nanofiber aerogel (GNA), in which cellulose acetate nanofibers are introduced in graphene aerogels for the first time to prevent the sheets from over-stacking and enhance connectivity of cell walls. This GNA exhibits excellent underwater stability and high adsorption capacity (> 800 mg/g) towards cationic dyes. Its density, pore structure and mechanical properties are easily tuned by varying the composition as well as compression deformation. The reshaping ability of GNA combined with co-deposition of polydopamine and polyethyleneimine makes it a superhydrophilic/underwater superoleophobic and shape-stable material to quickly separate oil-in-water emulsions with an extremely high flux (> 19,000 Lm(-2) h(-1) bar(-1)). On the other hand, after chemical modification and crosslinking via vapor deposition of hexadecyltrimethoxysilane, GNA turns to be a superhydrophobic and superelastic material that can adsorb organic liquids with an adsorption capacity of 230-734 g/g, being superior to most of known adsorbents. The materials are mass-producible and combine mechanical robustness and easy regeneration, providing a simple strategy for fabrication of multifunctional graphene-based aerogels satisfying various applications in water treatment.