Stability of montmorillonite edge faces studied using firstprinciples calculations

Hiroshi Sakuma, Yukio Tachi, Kenji Yotsuji, Shigeru Suehara, Tatsumi Arima, Naoki Fujii, Katsuyuki Kawamura, Akira Honda

研究成果: ジャーナルへの寄稿学術誌査読

2 被引用数 (Scopus)


The reactivity and stability of the edge faces of swelling clay minerals can be altered by layer charge and the stacking structure; however, these effects are poorly understood due to experimental limitations. The structure and stability of the montmorillonite {110}, {010}, {100}, and {130} edge faces with a layer charge of either y = 0.50 or y = 0.33 (e-/Si4O10) were investigated using first-principles calculations based on density functional theory. Stacked- and single-layer models were tested and compared to understand the effect of stacking on the stability of montmorillonite edge faces. Most stacked layers stabilize the edge faces by creating hydrogen bonds between the layers; therefore, the surface energy of the layers in the stacked-layer model is lower than in the single-layer model. This indicates that the estimates of edge face surface energy should consider the swelling conditions. Negative surface energies were calculated for these edge faces in the presence of chemisorbed water molecules. A high layer charge of 0.50 reduced the surface energy relative to that of the low layer charge of 0.33. The isomorphic substitution of Mg for Al increased the stability of interlayer Na ion positions, which were stable in the trigonal ring next to the Mg ions. The lowest surface energies of the {010} and {130} edge faces were characterized by the presence of Mg ions on edge faces, which had a strong cation adsorption site due to the local negative charge of the edges. The coordination numbers of O atoms around cations adsorbed to these edge faces were small in comparison to interlayers without water.

ジャーナルClays and Clay Minerals
出版ステータス出版済み - 8月 2017

!!!All Science Journal Classification (ASJC) codes

  • 水の科学と技術
  • 土壌科学
  • 地球化学および岩石学
  • 地球惑星科学(その他)


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