Adsorption behaviors of CO₂ and CH₄ on zeolites JSR and Na_nJSR using the GCMC simulations

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• 作者：Xiao-zhong Chu ; Song-song Liu ; Shou-yong Zhou ; Yi-jiang Zhao ; Wei-hong Xing…
• 关键词：Adsorption ; CO2 and CH4 separation ; GCMC method ; Modified JSR zeolite
• 刊名：Adsorption
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：22
• 期：8
• 页码：1065-1073
• 全文大小：702 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Surfaces and Interfaces and Thin Films
  Industrial Chemistry and Chemical Engineering
  Engineering Thermodynamics and Transport Phenomena
  
• 出版者：Springer Netherlands
• ISSN：1572-8757
• 卷排序：22

文摘

The adsorption behaviors of CO₂ and CH₄ on new siliceous zeolites JSR and Na_nJSR (n = 2, 8, 16) were simulated using the Grand Canonical Monte Carlo method. The adsorption isotherms of CO₂ became higher with an increase in the Na+ number at a low pressure range (<150 kPa), whereas the isotherms showed a crossover with increasing pressure and the adsorption amount became smaller at a high pressure range (>850 kPa). With an increase in Na+ number, the pore volume decreased as the pore space was occupied by increasing Na+ ions. Additionally, two energy peaks on the interaction energy curves implied that CO₂ was adsorbed on two active sites. On the other hand, the adsorption amount of CH₄ decreased with an increase in the Na+ number and only one energy peak was observed. Adsorption isotherms were well fitted with the Langmuir and Freundlich equations up to 1000 kPa and the adsorption affinity of CO₂ on Na₁₆JSR zeolite was highest. The adsorption capacities of CO₂ in the studied zeolites were up to 38 times higher than those of CH₄. Diffusion constants of CO₂ and CH₄ decreased with an increase in the adsorbed amount and Na+ number. Considering the adsorbed amount, adsorption selectivity and affinity, zeolites JSR with a low Na+ number (JSR and Na₂JSR) is a good candidate for a pressure swing adsorption in the separation of CO₂/CH₄ mixture whereas JSR zeolites with high Na+ ratios (Na₁₆JSR and Na₈JSR) may be a better selection for a vacuum swing adsorption.