Molecular Simulation of Methane Adsorption in Different Micro Porous Activated Carbons at Different Temperatures

We employed the previously developed micro porous activated carbon models of different pore sizes ranges of 9-11 A, 10-12 A, and 13-16 A that were constructed by molecular simulation method based on a random packing of platelets of carbon sheets, functionalized with oxygen containing groups, to study the adsorption behavior of methane molecules. In studying methane adsorption behavior, we used Grand Canonical Monte Carlo and Molecular Dynamics methods at different temperatures of 273.15, 298.15 and 303.15 K. Adsorption isotherms, isosteric heats of adsorption, adsorption energy distributions and porosity changes of the models during adsorption process were analyzed and discussed. Furthermore, radial distribution Functions, relative distribution and diffusion coefficients of methane molecules in activated carbon models at different temperatures were studied. After the analysis, the main results indicated that large micro pores activated carbons were favorable for storing methane at lower temperatures and small micro pores were the most favorable for adsorbing methane molecules at higher temperatures. Interestingly, the developed model structures showed high capacities to store methane molecule at ambient temperatures and low pressure.