Extension of the Brunauer-Emmett-Teller (BET) model for sorption of gas mixtures on the solid substances

BET model in its original or refined form (GAB) is widely used for studying the multilayer sorption of pure gases and vapors on the different solids. In this study, the BET model was theoretically extended for the prediction of gas mixtures sorption on the solids and the details of the model derivation with related assumptions were presented. Then, for better prediction, the extended GAB model which is a modified form of BET model was derived from the extended BET model. In order to check the validity of the proposed model, predictions of the extended GAB model were compared to the sorption data of several gas -solid systems including the light hydrocarbons, CO2 and N-2 gases on different types of activated carbon and silica gel from literature. Also, the predictions of IAST and EL models were compared to the results of the model and R-squared for all the models were reported. The extended model predicted adsorption behavior of gas mixtures on different solids accurately. Thus, this model is a simple and useful tool to raise our knowledge with respect to the physical sorption of gas mixtures on different solids. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The BET model, in its original or refined form (GAB), is commonly used to study the multilayer sorption of pure gases and vapors on various solids. This study theoretically extended the BET model for predicting gas mixtures sorption on solids, and derived the extended GAB model. The extended model accurately predicted the adsorption behavior of gas mixtures on different solids, making it a simple and useful tool for understanding physical sorption processes.