Experimental and theoretical determination of adsorption heats of CO2 over alkali metal exchanged ferrierites with different Si/Al ratio

0343891 - ÚFCH JH 2011 RIV GB eng J - Journal Article
Zukal, Arnošt - Pulido, A. - Gil, B. - Nachtigall, P. - Bludský, Ota - Rubeš, M. - Čejka, Jiří
Experimental and theoretical determination of adsorption heats of CO2 over alkali metal exchanged ferrierites with different Si/Al ratio.
Physical Chemistry Chemical Physics. Roč. 12, č. 24 (2010), s. 6413-6422. ISSN 1463-9076. E-ISSN 1463-9084
R&D Projects: GA ČR GA203/09/0143; GA MŠMT LC512; GA ČR GA203/08/0604
Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506
Keywords : adsorption * CO2 * FTIR spectroscopy
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 3.454, year: 2010

The adsorption of CO2 in Li-, Na-, and K-FER was investigated by a combination of volumetric adsorption experiments, FTIR spectroscopy, and density functional theory. Experimental isosteric heats of CO2, Qst, depend significantly on the cation size, cation concentration, and on the amount of adsorbed CO2. The differences observed in experimentally determined isosteric heats were interpreted at the molecular level based on good agreement between experimental and calculated characteristics. The highest interaction energies were found for CO2 adsorbed on so-called dual cation sites in which CO2 is bridged between two alkali metal cations. The formation of CO2 adsorption complexes on dual cation sites is particularly important on Na-FER and K-FER samples with higher cation concentration. On the contrary, the differences in Qst observed for Li-FER samples are due to the changes in the Li+ coordination with the framework.
Permanent Link: http://hdl.handle.net/11104/0186264