Investigation on the selective adsorption and separation properties of coal mine methane in ZIF-68 by molecular simulations

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• 作者：Qingzhao Li ; Maliang Ruan ; Yuannan Zheng ; Xiaoning Mei ; Baiquan Lin
• 关键词：Coal mine methane ; Adsorption and separation ; ZIF ; 68 ; Selectivity ; Molecular simulation
• 刊名：Adsorption
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：23
• 期：1
• 页码：163-174
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Industrial Chemistry/Chemical Engineering; Surfaces and Interfaces, Thin Films; Engineering Thermodynamics, Heat and Mass Transfer;
• 出版者：Springer US
• ISSN：1572-8757
• 卷排序：23

文摘

Methane adsorption separation by ZIF-68 had been investigated using Grand Canonical Monte Carlo and Molecular dynamics simulations. Results show that ZIF-68 is a more desirable material for CH₄ separation, even with CO₂ and H₂O presences. At 298 K and 1000 kPa condition, diffusion selectivity and permselectivity of ZIF-68 are 6.07 and 24.01 respectively. With temperature increasing, the adsorbed amount, selectivity of CH₄/N₂ and affinity constant (k₁) of CH₄ and N₂ would be reduced correspondingly. However, presences of moisture and CO₂ have more significant influence on the adsorption selectivity for CH₄ than for N₂, which would reduce the CH₄/N₂ separation effects as the moisture content increases. For CO₂ impurity, it is preferentially adsorbed at low pressures and lead to rapid saturations. However, CH₄ would be adsorbed more easily at higher pressure conditions, which can be attributed to the additional site IV. Methane adsorption selectivity of ZIF-68 at 298 K and 8000 kPa would be up to 16.48 and 15.37, respectively. Results indicate that ZIF-68 could be a promising candidate for methane adsorption separation efficiently and effectively. Research work may have important significance to the industrial application of ZIF-68 for methane separation from coal mine gases.