Equation of state for nanoconfined multicomponent mixture gases.

Abstract

Nanoconfined binary gas mixtures exhibit complex pressure-volume-temperature properties critical to applications such as shale gas extraction and membrane separation, yet traditional models such as Dalton's Law of Partial Pressures and Lorentz-Berthelot mixing rules fail to capture their behavior due to confinement-induced effects. This study investigates two-component gas mixtures in graphene nanochannels using molecular dynamics (MD) simulations, revealing that the pressure of gas mixtures decreases with the increasing potential energy due to enhanced adsorption. Extending our prior high-precision equation of state (EOS) for single-component gases [C. Sun et al., Phys. Rev. E 111, 025413 (2025)10.1103/PhysRevE.111.025413], we propose a different mixing rule based on Lennard-Jones potential parameters, surpassing the limitations of Lorentz-Berthelot mixing rules by incorporating gas type and molar ratio effects. Partition modification further accounts for nonuniform adsorption, decomposing pressure into bulk and adsorption contributions. The resulting EOS achieves predictive accuracies of 85%-98% across diverse gas component pairs (e.g., H_{2}-Ne, N_{2}-CO_{2}), component molar ratios, and total molecule numbers, compared to MD simulations. This work elucidates the interplay of potential energy, adsorption, and confinement, offering a robust framework for theoretical and engineering advancements in nanoconfined gas systems.