Lattice model of gas condensation within nanopores

We explore the thermodynamic behavior of gases adsorbed within a nanopore. The theoretical description employs a simple lattice gas model, with two species of site, expected to describe various regimes of adsorption and condensation behavior. The model includes four hypothetical phases: a cylindrical shell phase $\mathrm{}\left(S\right),$ in which the sites close to the cylindrical wall are occupied, an axial phase $\mathrm{}\left(A\right),$ in which sites along the cylinder’s axis are occupied, a full phase $\mathrm{}\left(F\right),$ in which all sites are occupied, and an empty phase $\mathrm{}\left(E\right).$ We obtain exact results at $T=0\mathrm{}$ for the phase behavior, which is a function of the interactions present in any specific problem. We obtain the corresponding results at finite T from mean field theory. Finally, we examine the model’s predicted phase behavior of some real gases adsorbed in nanopores.