| 초록 |
The framework of zeolites and their Si-to-Al ratio (SAR), surface area (SBET) and pore size have been correlated with the extent of CO2 adsorption at 25oC. Zeolite 13X and NaY had lower SAR values than that for ZSM-5 and SSZ-13. All zeolites used here indicated micropore sizes in the range of 4.8 - 5.5 Å; thus, they all could allow a readily access of CO2 with a molecular size of 3.3 Å even to the micropores. The extent of CO2 adsorption depended on the framework type of the zeoliltes as a primary parameter. In general, Zeolites with FAU framework, such as NaY and 13X, exhibited larger CO2 uptakes, compared to the other framework types. It seems that the SAR and SBET could also result in difference in the adsorption capacity between the zeolites. SSZ-13, SAPO-34 and 13X possessed a comparable SBET value each other; however, these zeolites showed visibly different CO2 uptakes and this variable is minor in effecting the adsorption performance. Therefore, the framework basicity of zeolites, that increases as a SAR value becomes low, may determine significance in CO2 adsorption. |
