Influence of unlike dispersive interactions on methane adsorption in graphite: a grand canonical Monte Carlo simulation and classical density functional theory study

Abstract

Activated carbons are popular adsorbents due to their large micro- and mesoporous volumes and high specific surface areas. Modeling adsorption behaviour using molecular computations is frequently undertaken, but the influence of the unlike intermolecular interactions on adsorption behaviour is often not well understood. This study employed grand canonical Monte Carlo simulations, and classical density functional theory coupled with a simple lattice gas model to study the influence of unlike intermolecular interactions on adsorption behaviour, with a focus on the dispersive interactions. Both approaches yielded qualitative agreement with experimental data from the literature, although only a fitted classical density functional theory approach agreed quantitatively. Changing the potential energy well depth of the methane-carbon interaction did not change the Langmuir-type adsorption behaviour observed, however, there was some dependence of the adsorption behaviour on the unlike interactions, depending on the thermodynamic conditions.