Multilayer adsorption equilibrium model for gas adsorption on solids

Abstract

Adaptation of the ENSIC model to physisorption of nitrogen or argon on a solid surface first led to a 3 parameters model called multilayer adsorption equilibrium model (MAE model). One of these parameters is related to the formation of a multilayer of adsorbate on the solid surface. Exploitation of data from the literature pointed out that this parameter does not depend on the nature of the solid surface and an average value was calculated in the case of N 2 and Ar. As a consequence, the MAE model can be considered as a 2 parameters model. Linearization of the model was established allowing an easy determination of surface areas of macroporous and some mesoporous solids. Fitting of isotherms of meso and macroporous solids has led to promising results compared to the ones obtained with the BET model. Moreover, adaptation of this model to microporous solids can also be used for an uncomplicated determination of porous volume and external surface. Results obtained from data of the literature were close to those obtained with the t-plot model.

Adsorption-based characterization of hierarchical metal–organic frameworks

“…Another model, the so-called multilayer adsorption equilibrium model (MAE), was recently developed. This model describes the formation of a multilayer film of adsorbate on the surface of a solid [Thomas and Schaetzel, 2013]. The authors fitted this model against many nitrogen adsorption isotherms at 77 K found in the literature.…”

A Simple Mechanistic Multilayer Model for the Rigorous Description of Brunauer–Emmett–Teller Type Isotherms

“…Approximation of the "Loose Layer" Multilayer Adsorption Theory: The MAE model. 5 Recently, Thomas et al 5 have published the description of a mechanistic theory to fit type II experimental adsorption data, the MAE model. The demonstration of this simple theory is based on the hypothesis that a new gas molecule susceptible to be adsorbed by the pore walls of the adsorbent is allowed to colonize a free adsorption site or a previously colonized site.…”

“…Simulation of adsorption isotherms with eq (MAE model). Isotherms generated with n 0 = 0.1 mol/kg, k 1 = 150, and different values of k 2 .…”

“…The BET theory authors give no relative pressure limit to the validity of the theory and apply the BET equation to the 0−0.7 relative pressure domain for at least one adsorption isotherm. 3 The aim of this paper is to propose a new equation, based on the same type of assumption that we used to demonstrate the multilayer adsorption equilibrium (MAE) theory 5 and the simple unified theory for adsorption and sorption 1 with an extension of these two models. The model is not a thermodynamic model but a model based on a simple and explicit multilayer molecular mechanism and will lead to a simple equation that will fit most type II adsorption isotherms with a robust calculated specific adsorption surface when changing the relative pressure fitting range.…”

Kinetic Approach to Multilayer Sorption: Equations of Isotherm and Applications

“…In 1938, Brunauer, Emmett, and Teller (BET) [1] extended Langmuir's monolayer theory [2][3][4][5] to multilayer adsorption. The BET equation derived was applied to a wide variety of gases on surfaces as well as to the sorption of water vapor by food materials [6][7][8].…”