Interplay of Montmorillonite鈥揌2O鈥搒cCO2 System between Mechanical Behavior and Adsorption: Molecular Dynamics

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• 作者：Weina Zhang ; Haixiang Hu ; Xiaochun Li ; Zhiming Fang
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：September 24, 2015
• 年：2015
• 卷：119
• 期：38
• 页码：21959-21968
• 全文大小：835K
• ISSN：1932-7455

文摘

Montmorillonite (MMT) constitutes most of fine-grained sedimentary rock, such as shale, mudstone, and siltstone. It is also applied in underground storage of carbon dioxide, petroleum drilling engineering, and material engineering. Although adsorption and mechanical behavior in MMT鈥揌₂O鈥揅O₂ is widely studied, little is known about interplay between them. In this work, we have investigated the interplay between mechanical behavior and adsorption in MMT with different proportion of H₂O and CO₂ content under super critical condition by molecular dynamic (MD) method. With respect to the calculated results, adsorption of H₂O and CO₂ can diminish stiffness of MMT. Meanwhile, diffusion of H₂O and CO₂ weakens because of stronger constrains deriving from geometry structure and hydrogen bond as the system undergoing compression test. Moreover, motion of H₂O is restrained by CO₂ molecules as self-diffusion coefficient decrease with the increase of CO₂. Hydrated MMT is more sensitive to deformation vertical to clay sheet which is confirmed by comparing changing tend of potential energy and stress. Process of adsorption can yield the stiffness of MMT structures while compression loading can slow down diffusion motions of adsobates. This impact we have revealed here is meaningful to understand mechanical properties of swelling MMT.