Molecular simulation of preferential adsorption of CO2 over CH4 in Na-montmorillonite clay material
Molecular simulation of preferential adsorption of CO2 over CH4 in Na-montmorillonite clay material
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DOI：
10.1016/j.apsusc.2015.08.101
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发表时间：
2015-11-30
影响因子：
6.7
通讯作者：
Yang, Xiaoning
中科院分区：
文献类型：
--
作者：
Yang, Nannan;Liu, Shuyan;Yang, Xiaoning
采用巨正则Monte Carlo模拟方法研究了二氧化碳和甲烷及其混合气体在钠基蒙脱土上的吸附行为。结果表明，两种吸附剂在粘土结构附近的吸附行为存在明显差异。纳蒙土对CO2的吸附能力明显高于CH4。用层间界面结构和吸附等温热表征了吸附行为和机理。同时，混合吸附表明，具有增强的吸附强度的CO2分子能够竞争性地取代粘土结构中的CH4分子。CO2相对于CH4的高分离选择性意味着使用粘土矿物从天然气混合物中分离CO2的可能性。层间钠阳离子和带负电荷的粘土表面可以提供与具有高四极矩的CO2分子的增强的相互作用，这是CO2的较高吸附负载的原因。(C)2015 Elsevier B.V.版权所有。
Grand canonical Monte Carlo simulations have been conducted to study the adsorption of carbon dioxide and methane, as well as their binary mixtures on Na-montmorillonite clay material. It was found that the adsorption behavior near the clay structure for the two species is distinctively different. The Namontmorillonite clay shows obviously high adsorption capacity for CO2, as compared with CH4. The adsorption behavior and mechanism have been characterized by the interlayer interfacial structures and isosteric heats of adsorption. Meanwhile, the mixture adsorption demonstrates that CO2 molecules with enhanced adsorption strength are able to competitively replace CH4 molecules within the clay structure. The high separation selectivity of CO2 over CH4 implies the possibility of separating CO2 from natural gas mixtures using the clay minerals. The interlayer sodium cations and negatively charged clay surface can provide enhanced interaction with CO2 molecules that have high quadrupole moment, which is responsible for the higher adsorption loading of CO2. (C) 2015 Elsevier B.V. All rights reserved.