This study presents the implementation of distinct fluid-fluid and wall-fluid interaction potentials to investigate the adsorption behavior of methane on a graphite surface. The Lennard-Jones (LJ) family of potentials with tunable softness and the Mie potential were utilized for fluid-fluid pair interactions, while Crowell-Steele (10-4) and Steele (10-4-3) potentials were employed for wall-fluid interactions. A parameter denoted as α was introduced to modulate the strength of wall-fluid attractions within the Steele (10-4-3) potential, enabling a transition from purely repulsive to strongly attractive wall-fluid interactions. Grand canonical Monte Carlo (GCMC) simulations were conducted to compute the isosteric heat of adsorption of methane on a graphite surface. These simulations were performed using an in-house Mathematica® code, which effectively incorporated the α parameter and accurately delineated fluid-fluid and wall-fluid interaction potentials. The results demonstrate a precise estimation of the isosteric heat of adsorption, thereby validating the separation of interaction types and the efficacy of the proposed methodology.

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