Highly Hydrophobic, Compressible, and Magnetic Polystyrene/Fe3O4/Graphene Aerogel Composite for Oil-Water Separation

A solvothermal technique to process novel graphene aerogel/Fe3O4/polystyrene composites with reticulated graphene structure is described. Porous Fe3O4 nanoparticles as a partial substitute for ethylenediamine assisted cross-linking and interconnections between graphene plates. Fe3O4 and polystyrene incorporation allowed a porous substructure to be formed on the reticulated graphene surfaces, effectively enhancing the hydrophobicity. The compressibility and directional recovery were achieved with the composite having an extremely low density of 0.005 g cm(-3), corresponding to a volume porosity of 99.7%. The crude oil intake capacity for the composite was 40 times its own mass after 10 water oil separation cycles, which is among the highest ever reported for oil absorbents. Furthermore, the incorporation of porous Fe3O4 nanoparticles enabled magnetism which, in combination with compressibility, allowed the oil-soaked graphene composite to be readily collected by a magnet and oil to be squeezed out before the next cyclic operation. The study implies a methodology for processing ultralow density graphene materials.