Description of the thickness of the adsorbed layer, identification of the instability characteristics of the liquid–vapour interface and assessment of criticality in elliptical pores through the Broekhoff de Boer theory

Abstract

This paper analyses the growth of the adsorbed layer during the course of N 2 adsorption verified in two types of elliptical pores, oblates and prolates, by means of the Broekhoff de Boer theory. The information provided by the value of the thickness of the adsorbed layer permits to characterize the geometrical features of the liquid-vapour interface at every stage of the isotherm, prior and at the onset of capillary condensation. The features of the liquid-vapour interface that are characteristic of the instability at the onset of capillary condensation were identified. Additionally, the critical ellipsoidal pore sizes were calculated, thus identifying the limit of stability for the formation of the liquid-vapour interface during N 2 adsorption.

Gas Sorption Characterization of Porous Materials Employing a Statistical Theory for Bethe Lattices

“…The CLJ 10-4-3 potential is always more strongly adsorbing, exhibits a deeper minimum than the CLJ 10-4 potential, and is expected to work better for pores with walls of finite thickness. Note that for the case of silica, the value of thickness Δ, is set to Δ = 0.36 nm. , Further details on the CLJ potentials are provided in the Supporting Information section.…”

“…Note that for the case of silica, the value of thickness Δ, is set to Δ = 0.36 nm. 83 , 84 Further details on the CLJ potentials are provided in the Supporting Information section .…”