A generalized analytical theory for adsorption of fluids in nanoporous materials

Abstract

An analytical theory is presented for the adsorption of fluids confined in zeolites, molecular sieves, and other nanoporous materials. The theory takes advantage of the localized adsorption sites within a zeolite and develops a statistical mechanical lattice model of adsorption. The theory is completely generalized and can be used to model the lattice of adsorption sites within any arbitrary zeolite. The theory also has the advantage of requiring very few parameters: it requires only 4 parameters to describe the adsorbent, which can be obtained from a potential energy map of the adsorbent. No molecular dynamics simulations are required for parametrization. The theory incorporates both the atomistic structure of the adsorbent and the fundamental physical mechanisms, which dictate the behaviour of fluids confined in nanoporous materials. Finally the theory has the practical advantage of computational efficiency. The theory can generate a complete isotherm in approximately 1 minute on a desktop PC (300 MHz), compared with tens of CPU hours of supercomputer or parallel cluster time necessary to perform the molecule dynamics simulations required to generate a few points of the same isotherm.