蒙脱土中间层扩散和电导率的分子动力学模拟,The Journal of Physical Chemistry C

当前位置： X-MOL 学术 › J. Phys. Chem. C › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

蒙脱土中间层扩散和电导率的分子动力学模拟
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2016-01-20 00:00:00 , DOI: 10.1021/acs.jpcc.5b10851
J. A. Greathouse ₁ , R. T. Cygan ₁ , J. T. Fredrich ₂ , G. R. Jerauld ₂

Affiliation

蒙脱石粘土矿物的夹层区域中水和离子的扩散是粘土-流体相互作用的类型和强度的直接探针。层间扩散也代表了分子模拟与宏观实验之间的重要联系。在这里，我们使用分子动力学模拟来研究蒙脱石夹层中阳离子和水扩散的趋势，特别关注层电荷，层间阳离子和阳离子电荷（钠或钙），水含量和温度的影响。对于钠蒙脱石，离子和水扩散系数的最大增加出现在一层和两层水合物之间，这对应于从内层到外层表面复合物的转变。Na-蒙脱土中离子和水扩散的计算活化能彼此相似，并且与水氢键能相似，这表明打破水-水和水-粘土氢键是层间扩散的可能机制。将层间扩散与本体电解质溶液的层间扩散进行比较，发现明显的趋势是扩散系数随电解质浓度的增加而降低，并且在大多数情况下，层间扩散结果与相应的本体溶液几乎一致。还比较了根据离子扩散系数计算出的电导率趋势。将层间扩散与本体电解质溶液的层间扩散进行比较，发现明显的趋势是扩散系数随电解质浓度的增加而降低，并且在大多数情况下，层间扩散结果与相应的本体溶液几乎一致。还比较了根据离子扩散系数计算出的电导率趋势。将层间扩散与本体电解质溶液的层间扩散进行比较，发现明显的趋势是扩散系数随电解质浓度的增加而降低，并且在大多数情况下，层间扩散结果与相应的本体溶液几乎一致。还比较了根据离子扩散系数计算出的电导率趋势。

"点击查看英文标题和摘要"

Molecular Dynamics Simulation of Diffusion and Electrical Conductivity in Montmorillonite Interlayers

The diffusion of water and ions in the interlayer region of smectite clay minerals represents a direct probe of the type and strength of clay–fluid interactions. Interlayer diffusion also represents an important link between molecular simulation and macroscopic experiments. Here we use molecular dynamics simulation to investigate trends in cation and water diffusion in montmorillonite interlayers, looking specifically at the effects of layer charge, interlayer cation and cation charge (sodium or calcium), water content, and temperature. For Na-montmorillonite, the largest increase in ion and water diffusion coefficients occurs between the one-layer and two-layer hydrates, corresponding to the transition from inner-sphere to outer-sphere surface complexes. Calculated activation energies for ion and water diffusion in Na-montmorillonite are similar to each other and to the water hydrogen bond energy, suggesting the breaking of water–water and water–clay hydrogen bonds as a likely mechanism for interlayer diffusion. A comparison of interlayer diffusion with that of bulk electrolyte solutions reveals a clear trend of decreasing diffusion coefficient with increasing electrolyte concentration, and in most cases the interlayer diffusion results are nearly coincident with the corresponding bulk solutions. Trends in electrical conductivities computed from the ion diffusion coefficients are also compared.

更新日期：2016-01-20

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南