Grass-modified graphene aerogel for effective oil-water separation

Grass-modified graphene aerogel (GGA) was successfully fabricated via simple, low-cost and environment-friendly hydrothermal treatment. The samples exhibited porous structure, low density of 6.99 mg/cm(3), good thermostability, excellent hydrophobicity with water contact angle of 146 degrees. The properties of graphene aerogel have been significantly improved by introducing grass powder, leading to highly efficient selective adsorption. The adsorption capacity of GGA ranged from 68.40 to 145.84 g/g for various liquid solvents, which is superior to that of unmodified graphene aerogel (GA). Moreover, GGA can be regenerated by repeated heat treatment and its adsorption capacity maintaining at above 90% of initial value after regeneration. GGA can realize oil-water separation of mixed solution by different manipulation methods. On one hand, GGA removed little oils in water through adsorption. On the other hand, GGA can act as filter media dealing with oil-water mixtures and collecting oils continuously by gravity or peristaltic pump. Good selectivity, high adsorption capacities and satisfactory recoverability make it possible to become a potential candidate in the field of oil-water separation and spill oil cleanup to realize environmental remediation. In the meantime, the incorporation of grass improves the performances of graphene aerogel in hydrophobicity, mechanical property and oil adsorption efficiency, providing a new path for high-value utilization of biomass waste. (C) 2019 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.