Spectral induced polarization of Na-montmorillonite dispersions

Abstract : Montmorillonite (Mt) clays have a high specific surface area and surface charge, which confer them remarkable adsorption properties. Nevertheless, their electrochemical and aggregation behavior are not completely elucidated because of the complexity of their microstructural and interfacial properties. In this work, the conductive and dispersive properties of Na-Mt suspensions of weight fractions 0.5 to 5.2% were investigated for the first time using the spectral induced polarization method. A four-electrode system was used to reduce errors introduced by electrode polarization and contact resistances. Complex conductivity spectra in the low-frequency range of 0.1 Hz to 45 kHz were successfully described using a triple layer model of the basal surface of Mt and a complex conductivity model that considers conduction of the diffuse layer and polarization of the Stern layer. Aggregate size distributions were inferred from inverted relaxation time distributions. We found that the negative and permanent surface charge of the basal plane of Na-Mt controls its quadrature (imaginary) conductivity, which is not very sensitive to pH and salinity (NaCl) in the 100 Hzto45 kHz frequency range. For lower frequencies, the sudden increase of the quadrature conductivity at the highest salinities was explained by considering coagulation of Na-Mt particles.
Type de document :
Communication dans un congrès
Clay Conference 2017, Sep 2017, Davos, Switzerland
Liste complète des métadonnées

https://hal-brgm.archives-ouvertes.fr/hal-01528386
Contributeur : Philippe Leroy <>
Soumis le : lundi 29 mai 2017 - 09:56:51
Dernière modification le : vendredi 17 novembre 2017 - 16:21:26

Fichiers

Davos_Leroy.pdf
Fichiers produits par l'(les) auteur(s)

Identifiants

  • HAL Id : hal-01528386, version 1

Collections

Citation

Philippe Leroy, Maximilian Weigand. Spectral induced polarization of Na-montmorillonite dispersions. Clay Conference 2017, Sep 2017, Davos, Switzerland. 〈hal-01528386〉

Partager

Métriques

Consultations de la notice

2

Téléchargements de fichiers

4