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- Title
Molecular Basis for the High CO<sub>2</sub> Adsorption Capacity of Chabazite Zeolites.
- Authors
Pham, Trong D.; Hudson, Matthew R.; Brown, Craig M.; Lobo, Raul F.
- Abstract
CO2 adsorption in Li-, Na-, K-CHA (Si/Al=6,=12), and silica chabazite zeolites was investigated by powder diffraction. Two CO2 adsorption sites were found in all chabazites with CO2 locating in the 8-membered ring (8MR) pore opening being the dominant site. Electric quadrupole-electric field gradient and dispersion interactions drive CO2 adsorption at the middle of the 8 MRs, while CO2 polarization due to interaction with cation sites controls the secondary CO2 site. In Si-CHA, adsorption is dominated by dispersion interactions with CO2 observed on the pore walls and in 8 MRs. CO2 adsorption complexes on dual cation sites were observed on K-CHA, important for K-CHA-6 samples due to a higher probability of two K+ cations bridging CO2. Trends in isosteric heats of CO2 adsorption based on cation type and concentration can be correlated with adsorption sites and CO2 quantity. A decrease in the hardness of metal cations results in a decrease in the direct interaction of these cations with CO2.
- Subjects
CARBON dioxide adsorption; ZEOLITES; DISPERSION (Chemistry); CATIONS; X-ray powder diffraction; CHABAZITE
- Publication
ChemSusChem, 2014, Vol 7, Issue 11, p3031
- ISSN
1864-5631
- Publication type
Article
- DOI
10.1002/cssc.201402555