Adsorption of Carbon Dioxide on High-Silica Zeolites with Different Framework Topology

Abstract

Adsorption isotherms of carbon dioxide were measured on six high-silica zeolites TNU-9, IM-5, SSZ-74, ferrierite, ZSM-5 and ZSM-11 comprising three-dimensional 10-ring (8-ring for ferrierite) at 273, 293, 313 and 333 K. Based on the known temperature dependence of CO2 adsorption, isosteric heats of adsorption were calculated. The obtained adsorption capacities and isosteric adsorption heats related to the amount of CO2 adsorbed have provided detailed insight into the carbon dioxide interaction with zeolites of different framework topology. The zeolites TNU-9 and ferrierite are characterized by pronounced energetic heterogeneity whereas due to the location of Na+ cations in the same positions the isosteric adsorption heats of CO2 adsorption on IM-5, ZSM-5 and ZSM-11 zeolites are rather constant for molecular ratio CO2/Na+ < 1. As IM-5 zeolite has a maximum adsorption capacity, it appears to have optimum properties for carbon dioxide separation.