Gibbs ensemble Monte Carlo simulation of supercritical CO_2 adsorption on HaA and NaX zeolites

摘要

Adsorption of supercritical carbon dioxide on two kinds of zeolites with identical chemical composition but different pore structure (NaA and NaX) was studied using the Gibbs ensemble Monte Carlo simulation.The model frameworks for the two zeolites with Si/Al ratio being unity have been chosen as the solid structures in the simulation.The adsorption behaviors of supercritical CO_2 on the NaA and NaX zeolites,based on the adsorption isotherms and isosteric heats of adsorption,were discussed in detail and were compared with the available experimental results.A good agreement between the simulated and experimental results is obtained for both the adsorbed amount and the bulk phase density.The intermediate configurational snapshots and the radial distribution functions between zeolite and adsorbed CO_2 molecules were collected in order to investigate the preferable adsorption locations and the confined structure behavior of CO_2.The structure behaviors of the adsorbed CO_2 molecules show various performances,as compared with the bulk phase,due to the confined effect in the zeolite pores.