Influence of activated carbon in zeolite X/activated carbon composites on CH₄/N₂ adsorption separation ability

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• 作者：Dongmei Zhang ; Wenping Cheng ; Jinghong Ma ; Ruifeng Li
• 关键词：Zeolite X/activated carbon composite ; Surface modification ; Methane ; Nitrogen ; Adsorption
• 刊名：Adsorption
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：22
• 期：8
• 页码：1129-1135
• 全文大小：652 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

A series of zeolite X/activated carbon composites with different ratio of zeolite X and activated carbon were prepared, which were adjusted by adding solid pitch powder and silicon dioxide as additional carbonaceous and silica source, respectively. The corresponding modified samples were obtained by treatment with the ammonium chloride solution. CH₄ and N₂ adsorption isotherms on all composites were determined within the pressure of 0–100 kPa at 298 K, and fitted with Henry model and Freundlich model. The results showed the adsorption separation abilities for CH₄ and N₂ were strongly influenced by activated carbon content, micropore structure and surface properties. The increase of activated carbon content increased the BET surface area, micropore surface area and micropore volume, leading to an enhanced CH₄ adsorption capacity and CH₄/N₂ adsorption selectivity. Compared with the unmodified composites, the modified composites showed higher CH₄/N₂ adsorption selectivity, and CH₄ adsorption capacity decreased slightly, which can be attributed to the reduction of the micropore structure parameters, the surface basic amount and basic strength. Furthermore, the modified composite HAX-3 presented the highest CH₄/N₂ selectivity of 3.4, and high CH₄ adsorption capacities, which is favorable for application in pressure swing adsorption processes.