Understanding the adsorption mechanism of carbon dioxide capture on hybrid zeolites prepared from rice husk ash via a modified statistical physics model

Abstract

In this study, a modified advanced double-layer model based on statistical physics was developed and utilized to explore the adsorption of carbon dioxide (CO₂) on two zeolites: W-ZSM-5 and W-silicalite-1. This model was formulated assuming that different chemical potentials were involved in the interfacial phenomenon, in contrast to other double-layer models that consider only one chemical potential. This formulation provides a better understanding of the multilayer adsorption of gases. The results obtained from this new model indicate that in the case of the CO₂-W-ZSM-5 system, CO₂ molecules altered their adsorption orientation from a mixed orientation (n = 0.88) involving both parallel and non-parallel configurations. Similarly, the molecules shifted from a multimolecular orientation (n = 1.17) to a perpendicular orientation for CO₂ adsorption on the W-silicalite-1 surface. The calculated adsorption energies confirmed the presence of an exothermic adsorption process governed by physical interactions between the CO₂ molecules and the surfaces of these zeolites. Finally, the adsorption energy distribution (AED) of both adsorbent surfaces was analyzed to determine the energy band activated during the CO₂ capture process. These findings contribute to a deeper understanding of CO₂ adsorption on zeolite surfaces. This new statistical physics model can be used for the process design of gas adsorption systems in various applications.