Water Adsorption at a Sodium Smectite Clay Surface: an Ab Initio Study of the First Stage

Clausen, Pascal; Andreoni, Wanda; Curioni, A.; Hughes, E. W.; Plummer, C. J. G.

doi:10.1021/jp901162s

Cited by 19 publications

(21 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For hydrated systems with a sodium cation, it has been shown that water adsorbs most preferably via a hydrogen bond to one of the surface oxygen atoms while oriented by its oxygen atom toward Na + . 47 These findings agree with our results for small kaolinite models. Thus, such initial structures of water and Na + placed close to FA on the kaolinite surface were applied in calculations presented in this paper.…”

Section: Models and Methodssupporting

confidence: 92%

“…In the presence of a sufficient amount of Na + , the surface charge of the mineral can be neutralized, making negatively charged mineral surfaces good adsorbents. 45 The cation's nearest environment contains one magnesium substitution in the octahedral sheet 46,47 or one aluminum substitution in the tetrahedral sheet. 48 Thus, in our study after substitution in the sheets, the model was kept electroneutral by the addition of a sodium cation (one of the most common exchangeable cations of kaolinite 26 ), which compensated a single (1−) negative surface charge.…”

Section: Models and Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Theoretical Study of the Roles of Na⁺and Water on the Adsorption of Formamide on Kaolinite Surfaces

et al. 2012

View full text Add to dashboard Cite

The adsorption of formamide (FA) on kaolinite surfaces and the roles of Na + and water on the adsorption were investigated theoretically using a density functional theory. The calculations reveal that adsorbed FA is able to form stable complexes with the tetrahedral and octahedral surfaces of kaolinite. The octahedral surface possesses a larger binding affinity toward FA than the tetrahedral site of kaolinite partially due to the presence of the surface hydroxyl groups that are more active in the intermolecular interactions than the basal oxygen atoms of the siloxane or tetrahedral sites. The calculated (basis set superposition error corrected) binding energies of FA on the kaolinite octahedral and tetrahedral surfaces are −14.8 and −13.7 kcal/mol, respectively. FA also forms slightly less stable complexes with the negatively charged kaolinite fragments than with neutral ones. The addition of a sodium cation plays a key role in this adsorption, while addition of one water molecule affects the binding strength insignificantly. A chemical reaction occurs involving the Na octahedral surface complex, during which hydrogen is removed from FA and binds with the surface oxygen. Full solvation decreases the adsorption affinity of FA toward both kaolinite surfaces. Estimated Gibbs free energies indicate that the adsorption of FA on most of the studied kaolinite clusters is thermodynamically feasible from both gas phase and water solution.

show abstract

Section: Models and Methodssupporting

confidence: 92%

Section: Models and Methodsmentioning

confidence: 99%

Theoretical Study of the Roles of Na⁺and Water on the Adsorption of Formamide on Kaolinite Surfaces

et al. 2012

View full text Add to dashboard Cite

show abstract

“…The cations within the interlayer space have the ability to hydrate [Norrish, 1954], resulting in continuous sheets of hydrogen-bonded water molecules that decrease tetrahedral layer contact area and reduce shear strength [Schleicher et al, 2013;Behnsen and Faulkner, 2013]. Furthermore, smectites can adsorb multiple (two to six) monolayers of water to their surface [Clausen et al, 2009]. Thus, the effect of water in smectite friction is strongly related both to adsorbed water on the mineral surface [Moore and Lockner, 2004] and to bound water in the interlayer.…”

Section: Strength Results and Effects Of Water Distributionmentioning

confidence: 99%

How phyllosilicate mineral structure affects fault strength in Mg‐rich fault systems

Sánchez-Roa

Faulkner

Boulton

et al. 2017

Geophysical Research Letters

View full text Add to dashboard Cite

The clay mineralogy of fault gouges has important implications for the frictional properties of faults, often identified as a major factor contributing to profound fault weakness. This work compares the frictional strength of a group of Mg‐rich minerals common in the Mg‐Al‐Si‐O compositional space (talc, saponite, sepiolite, and palygorskite) by conducting triaxial frictional tests with water or argon as pore fluid. The studied minerals are chemically similar but differ in their crystallographic structure. Results show that fibrous Mg‐rich phyllosilicates are stronger than their planar equivalents. Frictional strength in this group of minerals is highly influenced by strength of the atomic bonds, continuity of water layers within the crystals, and interactions of mineral surfaces with water molecules, all of which are dictated by crystal structure. The formation and stability of the minerals studied are mainly controlled by small changes in pore fluid chemistry, which can lead to significant differences in fault strength.

show abstract

“…V. Aggarwal et al have investigated adsorption of polar organic compounds onto montmorillonite. P. Clausen et al have computed the adsorption of volatile molecules . To the best of our knowledge, no theoretical studies focusing on the interaction between atrazine and clays have been performed.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the atrazine pesticide interaction with pyrophyllite and Ca²⁺-montmorillonite clay surfaces

et al. 2016

View full text Add to dashboard Cite

Atrazine, a pesticide belonging to the s-triazine family, is one of the most employed pesticides. Due to its negative impact on the environment, it has been forbidden within the European Union since 2004 but remains abundant in soils. For these reasons, its behavior in soils and water at the atomic scale is of great interest. In this article, we have investigated, using DFT, the adsorption of atrazine onto two different clay surfaces: a pyrophyllite clay and an Mg-substituted clay named montmorillonite, with Ca compensating cations on its surface. The calculations show that the atrazine molecule is physisorbed on the pyrophyllite surface, evidencing the necessity to use dispersion-corrected computational methods. The adsorption energies of atrazine on montmorillonite are two to three times larger than on pyrophyllite, depending on the adsorption pattern. The computed adsorption energy is of about -30 kcal mol for the two most stable montmorillonite-atrazine studied isomers. For these complexes, the large adsorption energy is related to the strong interaction between the chlorine atom of the atrazine molecule and one of the Ca compensating cations of the clay surface. The structural modifications induced by the adsorption are localized: for the surface, close to substitutions and particularly below the Ca cations; in the molecule, around the chlorine atom when Ca interacts strongly with this basic site in a monodentate mode. This study shows the important role of the alkaline earth cations on the adsorption of atrazine on clays, suggesting that the atrazine pesticide retention will be significant in Ca -montmorillonite clays. © 2016 Wiley Periodicals, Inc.

show abstract

Water Adsorption at a Sodium Smectite Clay Surface: an Ab Initio Study of the First Stage

Cited by 19 publications

References 22 publications

Theoretical Study of the Roles of Na⁺and Water on the Adsorption of Formamide on Kaolinite Surfaces

Theoretical Study of the Roles of Na⁺and Water on the Adsorption of Formamide on Kaolinite Surfaces

How phyllosilicate mineral structure affects fault strength in Mg‐rich fault systems

Theoretical study of the atrazine pesticide interaction with pyrophyllite and Ca²⁺-montmorillonite clay surfaces

Contact Info

Product

Resources

About

Water Adsorption at a Sodium Smectite Clay Surface: an Ab Initio Study of the First Stage

Cited by 19 publications

References 22 publications

Theoretical Study of the Roles of Na+and Water on the Adsorption of Formamide on Kaolinite Surfaces

Theoretical Study of the Roles of Na+and Water on the Adsorption of Formamide on Kaolinite Surfaces

How phyllosilicate mineral structure affects fault strength in Mg‐rich fault systems

Theoretical study of the atrazine pesticide interaction with pyrophyllite and Ca2+-montmorillonite clay surfaces

Contact Info

Product

Resources

About

Theoretical Study of the Roles of Na⁺and Water on the Adsorption of Formamide on Kaolinite Surfaces

Theoretical Study of the Roles of Na⁺and Water on the Adsorption of Formamide on Kaolinite Surfaces

Theoretical study of the atrazine pesticide interaction with pyrophyllite and Ca²⁺-montmorillonite clay surfaces