The texture of montmorillonites as influenced by the exchangeable inorganic cation and the drying method I: External surface area related to the stacking units of the aggregates

Stul, Michel; Leemput, L. Van

doi:10.1016/0376-4583(82)90028-0

Cited by 14 publications

(8 citation statements)

References 20 publications

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“…Literature results (Cebula et al 1980, Stul and Van Leemput 1982, Schramm and Kwak 1982 show that the surface area of dry montmorillonite increases with the size of the cation and that in dilute suspensions, the mean number of layers per tactoid increases with the cation atomic weight from 1 for Li § to 4 (or 5 depending of the equation used) in the case of Cs § Such results involve a splitting of the tactoids saturated with the smaller cations, in agreement with the present work.…”

Section: Textural Evolution During Water Adsorptionsupporting

confidence: 81%

Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. 1. The sodium-exchanged form

Cases¹,

Berend²,

Besson³

et al. 1992

Langmuir

405

358

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Abstract--Methods previously used to distinguish between water adsorbed on external surfaces and in the interlamellar space of Na-montmorillonite during adsorption and desorption of water vapor have been extended to a set of homoionic Li-, Na-, K-, Rb-and Cs-montmorillonite. The textural and structural features have been investigated at different stages of hydration and dehydration using controlled-rate thermal analysis, nitrogen adsorption volumetry, water adsorption gravimetry, immersion microcalorimetry and X-ray powder diffraction under controlled humidity conditions. During hydration, the size of the quasi-crystals decreases from 33 layers to 8 layers for Na-montmorillonite and from 25 layers to 10 layers for K-montmorillonite, but remains stable around 8-11 layers for Cs-montmorillonite. Each homoionic species leads to a one-layer hydrate, which starts forming at specific values of water vapor relative pressure. Li-, Na-and K-montmorillonite can form a two-layer hydrate. By comparing experimental X-ray diffraction patterns with theoretically simulated ones, the evolution of structural characteristics of montmorillonites during hydration or desorption can be described. Using structural and textural data, it is shown that during adsorption: (1) the rate of filling of interlamellar space of the one layer hydrate increases with the relative pressure but decreases with the size of the cations; and (2) the different hydrated states are never homogeneous.

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Section: Textural Evolution During Water Adsorptionsupporting

confidence: 81%

Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. 1. The sodium-exchanged form

Cases¹,

Berend²,

Besson³

et al. 1992

Langmuir

405

358

View full text Add to dashboard Cite

show abstract

“…Of particular importance are the changes in their hydraulic permeability, compressibility and water content as a result of the changes in physico-chemical conditions of the feed streams. Although various researchers have reported on clay behaviour as a result of changes in associated aqueous conditions [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], the study of how these changing conditions in the feed streams affect the structure of the accumulating solid assemblages on the membrane surface under very low-pressure membrane filtration operation is rare.…”

Section: Introductionmentioning

confidence: 99%

Effect of ionic strength and pH on hydraulic properties and structure of accumulating solid assemblages during microfiltration of montmorillonite suspensions

Santiwong

Guan

Waite

2008

Journal of Colloid and Interface Science

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“…Therefore, water on the external surface of the quasicrystal forms an approximate bilayer, whereas in the interlamellar space, an homogeneous 2-layer hydrate state is formed for Mg-, Ca-and Sr-montmorillonite and a predominant 2-(70%) and 3-layer hydrate interstratified is formed for Ba-montmorillonite. cation by a divalent one (Stul and Van Leemput 1982). Textural characteristics of dried materials seem difficult to generalize and are strongly dependent on the starting material (nature of exchangeable cation, texture in the natural occurrence, method used to prepare homoionic saturated samples) and on the drying conditions.…”

Section: Enthalpy Of Immersion or An Attempt To Characterize The Finmentioning

confidence: 99%

Mechanism of Adsorption and Desorption of Water Vapor by Homoionic Montmorillonite: 3. The Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ Exchanged Forms

Cases

1997

Clays and clay miner.

320

258

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Abstract--The swelling of some well-defined Mg-, Ca-, Sr-and Ba-homoionic montmorillonites was studied in the domain of water relative pressures lower than 0.95. This involves the expansion of the crystal lattice itself, commonly known as the "interlamellar expansion" or "inner crystalline swelling". The initial freeze-dried clays were characterized by nitrogen adsorption-desorption volumetry and controlled transformation rate thermal analysis. The evolution of the structural and textural properties of these different clays at different stages of hydration and dehydration was investigated using water adsorption gravimetry, immersion microcalorimetry at different precoverage water vapor relative pressures and X-ray diffraction (XRD) under controlled humidity conditions. Large textural variations are observed in the dry state depending on the exchangeable cations. The 2-layer hydrate exhibits the most ordered layer stacking. Water is mainly adsorbed in the interlamellar space. With increasing water pressure, each homoionic species leads to a l-layer hydrate and, with the exception of Ba-montmorillonite, to a predominant 2-layer hydrate. The relative pressure corresponding to the formation of the 2-layer hydrate decreases with increasing hydration energy of the interlayer cation. For Ca-, Sr-or Mg-montmorillonites, simulation of XRD patterns leads to the definition of successive homogeneous states corresponding to the 2-layer hydrate. Furthermore, it yields the water filling ratio corresponding to the different hydration states during adsorption and desorption of water vapor.

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The texture of montmorillonites as influenced by the exchangeable inorganic cation and the drying method I: External surface area related to the stacking units of the aggregates

Cited by 14 publications

References 20 publications

Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. 1. The sodium-exchanged form

Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. 1. The sodium-exchanged form

Effect of ionic strength and pH on hydraulic properties and structure of accumulating solid assemblages during microfiltration of montmorillonite suspensions

Mechanism of Adsorption and Desorption of Water Vapor by Homoionic Montmorillonite: 3. The Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ Exchanged Forms

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The texture of montmorillonites as influenced by the exchangeable inorganic cation and the drying method I: External surface area related to the stacking units of the aggregates

Cited by 14 publications

References 20 publications

Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. 1. The sodium-exchanged form

Mechanism of adsorption and desorption of water vapor by homoionic montmorillonite. 1. The sodium-exchanged form

Effect of ionic strength and pH on hydraulic properties and structure of accumulating solid assemblages during microfiltration of montmorillonite suspensions

Mechanism of Adsorption and Desorption of Water Vapor by Homoionic Montmorillonite: 3. The Mg2+, Ca2+, Sr2+ and Ba2+ Exchanged Forms

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Mechanism of Adsorption and Desorption of Water Vapor by Homoionic Montmorillonite: 3. The Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ Exchanged Forms