Dehydration of Ca-montmorillonite at the crystal scale. Part 2. Mechanisms and kinetics

Ferrage, Eric; Kirk, Caroline A.; Cressey, G.; Cuadros, Javier

doi:10.2138/am.2007.2397

Cited by 51 publications

(48 citation statements)

References 32 publications

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“…The possible statistical distribution of water content that may lead some interlayers to have slightly different water content could be one of the causes of the transition of hydrated layers at different RH values. 64 Still, additional studies involving spectroscopic and computational methods are necessary to fully test such an assumption.…”

Section: Discussionmentioning

confidence: 99%

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Ferrage¹,

Lanson²,

Michot³

et al. 2010

J. Phys. Chem. C

198

246

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The dehydration of two Na-saturated synthetic saponites with contrasting layer charge was studied by modeling the X-ray diffraction (XRD) patterns recorded along a water vapor desorption isotherm. The interlayer configurations used to reproduce the XRD data over a large angular range include Na + cations located in the interlayer midplane and H 2 O molecules normally distributed about one or two main positions for mono-and bihydrated layers, respectively. Although strongly reduced in comparison to natural smectites, hydration heterogeneity was systematically observed for these synthetic saponites, especially along the transition between two hydration states. Using improved models for the description of the interlayer organization, the influence of layer charge on the structure of interlayer water can be precisely assessed. In addition, the comparison with water contents obtained from water vapor gravimetry experiments allows discriminating the relative contributions of H 2 O molecules from 1W and 2W interlayers (crystalline water) and from the pore space network.

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Section: Discussionmentioning

confidence: 99%

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Ferrage¹,

Lanson²,

Michot³

et al. 2010

J. Phys. Chem. C

198

246

View full text Add to dashboard Cite

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“…Partially hydrated smectites can therefore be considered as solid solutions between hydrous and anhydrous smectite end members. This formalism facilitates the thermodynamic analysis of experimental data and allows relating the results with structural consideration, as derived from the analysis of XRD patterns (Ferrage et al, 2005(Ferrage et al, , 2007. Ransom and Helgeson's (1994a) model used the adsorption-desorption isotherms of homo-ionic SWy-1 montmorillonites, bracketing the water content of the smectite as a function of the relative humidity.…”

Section: Basic Conceptsmentioning

confidence: 99%

“…The number of moles of water molecules close to vapor saturation can actually be extremely variable. Ferrage et al (2005Ferrage et al ( , 2007 have shown that the amount of water molecules for two water layers is ranging from 3.3 to 3.8 H 2 O per O 10 (OH) 2 . Vidal and Dubacq (2009) proposed a model with three layers of water and a maximum amount of 6.3 mol of water (per O 10 (OH) 2 ).…”

Section: Determination Of the Maximal Number Of Moles Of Interlayer Wmentioning

confidence: 99%

Hydration thermodynamics of the SWy-1 montmorillonite saturated with alkali and alkaline-earth cations: A predictive model

Vieillard

Blanc

Fialips

et al. 2011

Geochimica et Cosmochimica Acta

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“…The (force) fitted data are then used to determine the dimensionality of the single 'rate-determining step ' (e.g. Bray and Redfern 2000;Cattaneo et al 2003;Perrillat et al 2005;Ferrage et al 2007;Carbone et al 2008;Ballirano and Melis 2009;Chollet et al 2009;Inoue et al 2009;Tokiwai and Nakashima 2010;Gualtieri et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Kinetics of the chrysotile and brucite dehydroxylation reaction: a combined non-isothermal/isothermal thermogravimetric analysis and high-temperature X-ray powder diffraction study

2013

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a much higher apparent E a characterised by an initial stage of around 290 kJ/mol. Afterwards, the apparent E a comes down to around 250 kJ/mol at α ~ 65 % before rising up to around 400 kJ/mol. The delivered kinetic data have been investigated by the z(α) master plot and generalised time master plot methods in order to discriminate the reaction mechanism. Resulting data verify the multi-step reaction scenarios (reactions governed by more than one rate-determining step) already visible in E a versus α plots.Keywords Serpentine dehydroxylation · Generalised master plot · Chrysotile · Brucite · Thermogravimetry · In situ high-temperature X-ray powder diffraction

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Dehydration of Ca-montmorillonite at the crystal scale. Part 2. Mechanisms and kinetics

Cited by 51 publications

References 32 publications

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Hydration Properties and Interlayer Organization of Water and Ions in Synthetic Na-Smectite with Tetrahedral Layer Charge. Part 1. Results from X-ray Diffraction Profile Modeling

Hydration thermodynamics of the SWy-1 montmorillonite saturated with alkali and alkaline-earth cations: A predictive model

Kinetics of the chrysotile and brucite dehydroxylation reaction: a combined non-isothermal/isothermal thermogravimetric analysis and high-temperature X-ray powder diffraction study

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