scholarly journals Molecular Dynamics Study of the Effect of Layer Charge and Interlayer Cations on Swelling of Mixed-Layer Chlorite–Montmorillonite Clays

2020 ◽  
Vol 124 (4) ◽  
pp. 2553-2561 ◽  
Author(s):  
Mahsa Rahromostaqim ◽  
Muhammad Sahimi
Keyword(s):  
Molecular Dynamics ◽  
Mixed Layer ◽  
Layer Charge ◽  
Interlayer Cations ◽  
Montmorillonite Clays

scholarly journals Effect of Crystal Chemistry Properties on the Distribution Characteristics of H2O and Na+ in Na-Montmorillonite Interlayer Space: Molecular Dynamics Simulation Study

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 162 ◽  
Author(s):  
Qiu ◽  
Liu ◽  
Jiang ◽  
Chen ◽  
Wang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Charge Density ◽  
Crystal Chemistry ◽  
Dynamics Simulation ◽  
Layer Charge ◽  
Isomorphic Substitution ◽  
Substitution Ratio ◽  
The Impact ◽  
Tetrahedral Substitution

At monolayer hydration state, the spatial distribution of H2O and Na+ in the interlayer of Na-montmorillonite (Na-MT) with different crystal chemistry properties was investigated by the molecular dynamics simulation method. The simulation results show that when layer charge density increases, H2O will move and form hydrogen bonds with O in tetrahedral surfaces (Ot) at a distance of 1.676 ± 0.043 Å. The impact of isomorphic substitution on the relative concentration of H2O depends largely on the layer charge density of Na-MT, when layer charge density is high, H2O move obviously to both sides of Na-MT sheets with the increase of octahedral substitution ratio. Nevertheless, Na+ coordinate with Ot at a distance of 2.38 Å, and the effect of isomorphic substitution ratio on the diffusion of Na+ is opposite to that of H2O. The mobility of both H2O and Na+ decreases with the increase of layer charge density or tetrahedral substitution ratio. The radial distribution function of Na-Ow (O in H2O) shows that the coordination strength between Na+ and Ow decreases with the increase of layer charge density or tetrahedral substitution ratio, and Na+ are hydrated by four H2O at a Van der Waals radius of 2.386 ± 0.004 Å. The research results can provide a theoretical basis for the efficient application of Na-MT at the molecular and atomic levels.

Molecular dynamics study of the swelling patterns of Na/Cs-, Na/Mg-montmorillonites and hydration of interlayer cations

2017 ◽  
Vol 43 (8) ◽  
pp. 575-589 ◽  
Author(s):  
Jiafang Xu ◽  
Moussa Camara ◽  
Jinxiang Liu ◽  
Lin Peng ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Interlayer Cations

Interaction between glycine and Na-, Caand Cu-rich smectites

Clay Minerals ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 635-641 ◽  
Author(s):  
E. Benincasa ◽  
M. F. Brigatti ◽  
C. Lugli ◽  
L. Medici ◽  
L. Poppi
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Sequential Extraction ◽  
Layer Charge ◽  
Close Attention ◽  
Interlayer Cations ◽  
Extraction Procedures ◽  
Zwitterionic Form ◽  
Sequential Extraction Procedures ◽  
Thermal Curves

AbstractThe interactions between glycine and two Na-, Ca- and Cu-exchanged smectites with different layer-charge location were studied. The sorption of glycine depends on the nature of the interlayer cations (Ca < Na < Cu), and on the type of smectite. Sequential extraction procedures were carried out in order to test the possibility of removing metals and/or glycine from the smectite interlayer. By the end of the treatments, the release of the amino acid from the substrates, with the exception of Cu-rich smectite, was virtually complete. The thermal curves of glycine-smectites confirm the stronger bonding of the amino acid with Cu-exchanged samples, and FTIR spectra indicate that glycine is mainly sorbed in the zwitterionic form. The data obtained suggest that in investigations into mechanisms of the binding of metals by minerals and their subsequent mobilization, amino acids merit close attention.

The influence of exchangeable aluminium ion concentration and of layer charge on the catalytic activity of montmorillonite clays

1989 ◽  
Vol 2 (3) ◽  
pp. 125-128 ◽  
Author(s):  
J. H. Purnell ◽  
J. M. Thomas ◽  
P. Diddams ◽  
J. A. Ballantine ◽  
W. Jones
Keyword(s):  
Catalytic Activity ◽  
Ion Concentration ◽  
Layer Charge ◽  
Aluminium Ion ◽  
Montmorillonite Clays

scholarly journals Molecular Dynamics Simulation in the Interlayer of Mixed-Layer Clays Due to Hydration and Swelling Mechanism

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 586
Author(s):  
Yu Yang ◽  
Sanjeev Adhikari ◽  
Guoyuan Xu
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonds ◽  
Interaction Energy ◽  
Mixed Layer ◽  
Bound Water ◽  
Swelling Behavior ◽  
Dynamics Simulation ◽  
Basal Spacing ◽  
Water Interaction ◽  
Swelling Mechanism

The swelling behavior of clay minerals is widely known for its importance in soil and environmental sciences and its detrimental effects in engineering fields. Although more than 70 percent of all clays are of mixed-layer types, the vast majority of the previous experiments and simulations are focused on pure clays, which cause the swelling mechanism of the widespread mixed-layer clay (MLC) and its role in soils are little understood, especially the most common illite-montmorillonite (I-M) mixed-layer clay (MLC). This paper reports on a molecular dynamics (MD) study of the differences in swelling behavior between I-M MLCs containing K+ and Na+ and Na-montmorillonite (MMT). It captures the evolution of quantitative properties such as basal spacing d, interaction energy, and many hydrogen bonds in the clay interlayer, increasing hydration for the first time through the scripts. It is found that MLCs have smaller swellings than Na-MMT due to the asymmetric interlayer charges and mixed counterions in the I-M interlayer. However, in terms of the interaction energy for the in-depth reason of swelling, it is found that the clay-clay interaction energy and the clay-ion interaction energy drop, while the clay-water interaction energy increases with increasing hydration. In addition, the attractive interaction of clay-bound water seriously promotes swelling, and it is mainly composed of Coulomb interaction and Van der Waals interaction. The higher the K+ concentration, the more noticeable these phenomena are. Besides, it is also reported that the number and distribution mechanism of hydrogen bonds in MLCs are very different from that of pure clay. This work provides insight into the molecular mechanism for initial swelling and clay-bound water interaction in widespread MLCs. This will help to decipher its specific role in soils and minimize clay swelling.

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