Adsorption of CO2 on ZSM-5 Zeolite: Analytical Investigation via a Multilayer Statistical Physics Model

Abstract

In this paper, a synthesized zeolite (ZSM-5) is used as an adsorbent to analyze the adsorption phenomenon of carbon dioxide. This investigation, based on the statistical physics treatment, applied the multilayer model with saturation to understand the CO2 adsorption on four samples, namely M-ZSM-5 (M = Na+, Mg2+, Zn2+, La3+), at various temperatures T = 0 °C, 30 °C and 60 °C. The modeling results indicated that CO2 adsorption occurred via a non-parallel orientation on the ZSM-5 surface. The CO2 adsorption capacities varied from 26.14 to 28.65 cm3/g for Na-ZSM-5, from 25.82 to 27.97 cm3/g for Mg-ZSM-5, from 54.82 to 68.63 cm3/g for La-ZSM-5 and from 56.53 to 74.72 cm3/g for Zn-ZSM-5. Thus, Zn-ZSM-5 exhibits the highest adsorption amount. The analysis of the adsorption energies shows that the adsorption of CO2 on ZSM-5 zeolite is a physisorption phenomenon that could be controlled thanks to the energy parameters obtained via the numerical findings using the multilayer statistical model. Finally, the distribution of site energy was determined to confirm the physical character of the interactions between adsorbate/adsorbent and the heterogeneity of the zeolite surface.