Xenon adsorption isotherms on chabazite. Statistical physics modeling investigation: Adsorption energy and pore size distributions computation

Abstract In order to investigate the toxic Xenon removal by an adsorption process on chabazite, the grand canonical formalism of statistical physics has been used. This conducted statistical physics treatment enabled us to draw information about the interactions between Xenon atoms and chabazite surface through the determined physico-chemical parameters. The adsorption energy and pore size distributions have been derived by using an integral expression based on a monolayer model as local isotherm. The fitted values of the steric coefficient showed that one chabazite active site can trap only one Xenon atom. The evaluated densities of receptor sites played an important role in the assess of the adsorption capacity. Ca-CHA sample showed the maximum adsorption capacity (2.36 mmol.g-1). By using the adsorption energy distributions (GD), the physisorbed character of the Xenon adsorption on chabazite samples was brought out. The diversification of the active sites is noticed for all chabazite samples. The highest adsorption energies are observed in the case of the Xenon adsorption on CA-CHA sample. Furthermore, by using the pore size distribution (PSD), the microporous character of all samples (Ca-CHA, Cs-CHA, Li-CHA, K-CHA and Rb-CHA) has been showed. The maximum surface area was found to be 187.23 m2. g-1 for Ca-CHA. The calculated surface tensions are in the range [10.07E-5 N.m-1-13.46E-5 N.m-1]. Finally, by combining the thermodynamical and statistical physics treatments, the chemical potential describing the Xenon adsorption, is calculated at different pressures.