Unconventional, Highly Selective CO2 Adsorption in Zeolite SSZ-13

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• 作者：Matthew R. Hudson ; Wendy L. Queen ; Jarad A. Mason ; Dustin W. Fickel ; Raul F. Lobo ; Craig M. Brown
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：February 1, 2012
• 年：2012
• 卷：134
• 期：4
• 页码：1970-1973
• 全文大小：251K
• 年卷期：v.134,no.4(February 1, 2012)
• ISSN：1520-5126

文摘

Low-pressure adsorption of carbon dioxide and nitrogen was studied in both acidic and copper-exchanged forms of SSZ-13, a zeolite containing an 8-ring window. Under ideal conditions for industrial separations of CO₂ from N₂, the ideal adsorbed solution theory selectivity is >70 in each compound. For low gas coverage, the isosteric heat of adsorption for CO₂ was found to be 33.1 and 34.0 kJ/mol for Cu- and H-SSZ-13, respectively. From in situ neutron powder diffraction measurements, we ascribe the CO₂ over N₂ selectivity to differences in binding sites for the two gases, where the primary CO₂ binding site is located in the center of the 8-membered-ring pore window. This CO₂ binding mode, which has important implications for use of zeolites in separations, has not been observed before and is rationalized and discussed relative to the high selectivity for CO₂ over N₂ in SSZ-13 and other zeolites containing 8-ring windows.