Studying of the adsorption and diffusion behaviors of methane on graphene oxide by molecular dynamics simulation.

Abstract

In this work, the sorption and diffusion behaviors of the methane on graphene oxide (GO) were investigated by molecular dynamics (MD) simulation. The sorption isotherms at different temperatures were calculated using the Grand Canonical Monte Carlo (GCMC) method and using the Langmuir adsorption model to fit those isotherms. To investigate the effect of the number of graphene oxide layers on the adsorption process, methane adsorption isotherms were calculated for graphene oxide with 1, 2, and 3 layers. The adsorption parameters including Langmuir adsorption constant, the entropy and the enthalpy of adsorption, collision flux, the rate of adsorption, and the rate of desorption were investigated in this work. The highest amount of adsorption calculated is related to graphene oxide three layers. The methane diffusion coefficients and diffusion activation energies were estimated at different temperatures by MD simulation coupled with Einstein relationship. The maximum diffusion coefficient calculated of methane at 348K was 49 × 10-10m2/s.