Sorption Properties of Graphene Aerogel with Respect to Methane

摘要

Abstract A new nanostructured carbon material has been synthesized in the form of aerogel on the basis of reduced graphene oxide using supercritical methods of hydrogel processing in the medium of isopropyl alcohol. The synthesized material is characterized by a sufficiently high BET (Brunauer, Emmett, and Teller) specific area, 657 m2/g, with high specific volume of pores according to the density functional theory (DFT), 0.766 cm3/g, which provides wide opportunities of its application for adsorption of energetically important gases, in particular, methane. A favorable factor for improvement of adsorption–desorption is high volume of mesopores with the diameters of about 4.5–6.5 nm. Methane adsorption has been studied on the synthesized graphene aerogel at temperatures of 298.15, 303.15, 313.15 K and pressures up to 10 MPa. The maximum methane adsorption at 298.15 K and 10 MPa reaches 7.31 mmol/g. Characteristic adsorption variables have been analyzed using empirical models of the Langmuir and Freundlich isotherms. Adsorption has been analyzed at the level of evaluation of thermodynamic parameters, which indicate its change from a random to ordered state and its exothermic and physical essence. The obtained results can be used in the design of storage systems of adsorbed natural gas.