Swelling of Na∕Mg-montmorillonites and hydration of interlayer cations: A Monte Carlo study

Meleshyn, Artur; Bunnenberg, Claus

doi:10.1063/1.2011392

Cited by 40 publications

(28 citation statements)

References 30 publications

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“…There is a large body of experimental [ Mooney et al ., ; Chiou and Rutherford , ; Cuadros , ; Morodome and Kawamura , ; Woodruff and Revil , ] and modeling studies [ Skipper et al ., ; Chang et al ., ; Chavez et al ., ; Meleshyn and Bunnenberg , ; Ferrage et al ., , ; De Pablo et al ., ] on interlayer distances in montmorillonite with increasing relative humidity or water vapor pressure. While the conditions in these studies differ from ours, they are useful in helping to understand the role of the interlayer cation in the swelling mechanism.…”

Section: Discussionmentioning

confidence: 99%

Permeability and frictional strength of cation‐exchanged montmorillonite

Faulkner

2013

JGR Solid Earth

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[1] Smectites, such as montmorillonite, are abundant throughout the upper crust and are commonly found in fault gouge. They are known for their weak frictional strength and low permeability. Smectites are swellable clays in which the interlayer cation can easily be exchanged. In this study, we measure permeability and frictional strength of montmorillonite exchanged with Na + , K + , Ca 2+ , and Mg 2+ using a triaxial shear apparatus. We find that the interlayer cation influences both permeability and the friction coefficient. K-montmorillonite is significantly stronger ( = 0.26) than Na-montmorillonite ( = 0.15) and Ca-or Mg-montmorillonite ( = 0.11). Permeability for all four clays is between 10 -21 and 10 -23 m 2 in the pressure range between 10 MPa and 100 MPa, with K-montmorillonite the most permeable clay gouge. Mg-, Ca-, and Na-montmorillonite show relative similar permeabilities of which Na-montmorillonite is least permeable. We relate the higher frictional strength and permeability of K-montmorillonite to reduce interlayer water content caused by differences in cation hydration and adsorption. The results show that the rapid cation exchange process in montmorillonite can influence macroscale parameters, such as permeability and strength, which can contribute to changes in local pressure conditions and frictional strength of shallow fault zones.Citation: Behnsen, J., and D. R. Faulkner (2013), Permeability and frictional strength of cation-exchanged montmorillonite,

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Section: Discussionmentioning

confidence: 99%

Permeability and frictional strength of cation‐exchanged montmorillonite

Faulkner

2013

JGR Solid Earth

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“…The different interlayer cations vest multiple properties to MMTs thus the MMTs appeared different swelling abilities and diffusion coefficients in solvent . The reason for these differences in properties may be due to the hydration of interlayer cations .…”

Section: Introductionmentioning

confidence: 99%

Correlation of exfoliation performance with interlayer cations of montmorillonite in the preparation of two‐dimensional nanosheets

et al. 2019

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Montmorillonite (MMT) can be exfoliated into nanosheets used in a wide range of applications as two-dimensional (2D) material. The exfoliated MMT nanosheets with high diameter-thickness ratio appear to show superior properties in preparation of nanocomposites and other functional materials. In this work, the correlation of exfoliation performance with interlayer cations of MMT in the preparation of 2D nanosheets was investigated. The thickness and lateral diameter of MMT nanosheets were quantitatively measured by atomic force microscopy (AFM) technique. AFM results showed the exfoliated K-MMT had larger lateral diameter and thinner thickness than the exfoliated Ca-MMT under the same exfoliation conditions. Molecular simulation was applied to investigate the interlayer-binding energy (IBE), population analysis and density of states. K-MMT structures tend to have higher in-plane chemical bond intensity than Ca-MMT because of the impact of antibonding. The IBE of K-MMT was higher than that of Ca-MMT after the sorption of water molecules into the neighboring monolayers, indicating that thinner naonosheets tend to be easier obtained from Ca-MMT than K-MMT in liquid exfoliation. These findings might be helpful for the preparation and application of 2D MMTNS through controlling interlayer cation species and the exfoliation properties of MMT. K E Y W O R D Satomic force microscopy,

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“…[10] In a mixed valent montmorillonite, the exchangeable cations within the interlayers and in between the clay particles may comprise either a single cation species or a mixture of all cation types available in the clay [Mering and Glasser, 1954;Keren and Shainberg, 1979;Meleshyn and Bunnenberg, 2005]. The repulsive energy due to hydration of divalent exchangeable cations is significantly greater than that for monovalent ions [MacEwan, 1954].…”

Section: Literature Reviewmentioning

confidence: 99%

Swelling pressure of a divalent‐rich bentonite: Diffuse double‐layer theory revisited

Schanz

Tripathy

2009

Water Resources Research

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[1] Physicochemical forces are responsible for the swelling pressure development in saturated bentonites. In this paper, the swelling pressures of several compacted bentonite specimens for a range of dry density of 1.10-1.73 Mg/m 3 were measured experimentally. The clay used was a divalent-rich Ca-Mg-bentonite with 12% exchangeable Na + ions. The theoretical swelling pressure-dry density relationship for the bentonite was determined from the Gouy-Chapman diffuse double-layer theory. A comparison of experimental and theoretical results showed that the experimental swelling pressures are either smaller or greater than their theoretical counterparts within different dry density ranges. It is shown that for dry density of the clay less than about 1.55 Mg/m 3 , a possible dissociation of ions from the surface of the clay platelets contributed to the diffuse double-layer repulsion. At higher dry densities, the adsorptive forces due to surface and ion hydration dominated the swelling pressures of the clay. A comparison of the modified diffuse double-layer theory equations proposed in the literature to determine the swelling pressures of compacted bentonites and the experimental results for the clay in this study showed that the agreement between the calculated and experimental swelling pressure results is very good for dry densities less than 1.55 Mg/m 3 , whereas at higher dry densities the use of the equations was found to be limited.

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Swelling of Na∕Mg-montmorillonites and hydration of interlayer cations: A Monte Carlo study

Cited by 40 publications

References 30 publications

Permeability and frictional strength of cation‐exchanged montmorillonite

Permeability and frictional strength of cation‐exchanged montmorillonite

Correlation of exfoliation performance with interlayer cations of montmorillonite in the preparation of two‐dimensional nanosheets

Swelling pressure of a divalent‐rich bentonite: Diffuse double‐layer theory revisited

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