Spectral induced polarization of Na-montmorillonite dispersions

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:505

Article

Leroy, Philippe^1,2  Weigand, Maximilian³  Meriguet, Guillaume⁴  Zimmermann, Egon⁵  Tournassat, Christophe⁶  Kemna, Andreas³  Huisman, Johan Alexander⁷ 

[1] French Geol Survey, BRGM, F-45060 Orleans, France

[2] Uppsala Univ, Dept Earth Sci, S-75236 Uppsala, Sweden

[3] Univ Bonn, Steinmann Inst, Dept Geophys, D-53115 Bonn, Germany

[4] Pierre & Marie Curie Univ, PHENIX, CNRS, UMR 8234, F-75252 Paris, France

[5] Forschungszentrum Julich, Cent Inst Engn Elect & Analyt, Elect Syst, ZEA 2, D-52425 Julich, Germany

[6] Univ Orleans, CNRS INSU BRGM, UMR 7327, Inst Sci Terre Orleans, F-45071 Orleans, France

[7] Forschungszentrum Julich, Inst Bio & Geosci, IBG 3, Agrosphere Inst, D-52425 Julich, Germany

关键词: Na-montmorillonite;    Dispersions;    Spectral induced polarization;    Conductivity;    Dielectric permittivity;    Basal plane;    Surface charge;    Stern layer;    Diffuse layer;   

DOI  :  10.1016/j.jcis.2017.06.071

来源: Elsevier

【 摘 要 】

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 0.5-5.2% 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 (NaCI) 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. (C) 2017 Elsevier Inc. All rights reserved.

【 授权许可】

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