Adsorption and Separation of CO2 on KFI Zeolites: Effect of Cation Type and Si/Al Ratio on Equilibrium and Kinetic Properties

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• 作者：Tom Remy ; Sunil A. Peter ; Leen Van Tendeloo ; Stijn Van der Perre ; Yannick Lorgouilloux ; Christine E. A. Kirschhock ; Gino V. Baron ; Joeri F. M. Denayer
• 刊名：Langmuir
• 出版年：2013
• 出版时间：April 23, 2013
• 年：2013
• 卷：29
• 期：16
• 页码：4998-5012
• 全文大小：767K
• 年卷期：v.29,no.16(April 23, 2013)
• ISSN：1520-5827

文摘

Selective separation of CO₂ is becoming one of the key technologies in the (petro-) chemical industry. This study focuses on the adsorption and separation of CO₂ from CH₄ on a new low-silica (LS) type of the eight-membered ring KFI zeolite. A series of alkali (Li, Na, K) and alkaline-earth (Mg, Ca, Sr) exchanged samples of the new LS KFI were synthesized and characterized. LS Li-KFI showed the largest pore volume, whereas LS Na-KFI and LS K-KFI were inaccessible for Argon at 87 K. Adsorption of CO₂ at 303 K demonstrated the dominant quadrupolar interaction on alkali-exchanged LS KFI samples. LS Li-KFI showed the largest capacities upon high pressure isotherm measurements of CO₂ (4.8 mmol/g), CH₄ (2.6 mmol/g), and N₂ (2.2 mmol/g) up to 40 bar at 303 K. The performance of the new LS KFI was compared to a KFI sample (ZK-5) with a higher Si/Al ratio. Isotherm measurements and dynamic breakthrough experiments demonstrated that ZK-5 samples show larger working capacities for CO₂/CH₄ separations at low pressure. Li-ZK-5 and Na-ZK-5 show the highest capacities and high selectivities (similar to benchmark 13X).