%0 Journal Article
%A Leroy, Philippe
%A Weigand, Maximilian
%A Mériguet, Guillaume
%A Zimmermann, Egon
%A Tournassat, Christophe
%A Fagerlund, Fritjof
%A Kemna, Andreas
%A Huisman, Johan Alexander
%T Spectral induced polarization of Na-montmorillonite dispersions
%J Journal of colloid and interface science
%V 505
%@ 0021-9797
%C Amsterdam [u.a.]
%I Elsevier
%M FZJ-2017-04559
%P 1093 - 1110
%D 2017
%X Montmorillonite (Mt) clays have a high specific surface area and surface charge, which confer themremarkable adsorption properties. Nevertheless, their electrochemical and aggregation behavior arenot 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 systemwas used to reduce errors introduced by electrode polarization and contact resistances. Complexconductivity spectra in the low-frequency range of 0.1 Hz to 45 kHz were successfully described usinga triple layer model of the basal surface of Mt and a complex conductivity model that considers conductionof the diffuse layer and polarization of the Stern layer. Aggregate size distributions were inferredfrom inverted relaxation time distributions. We found that the negative and permanent surface chargeof the basal plane of Na-Mt controls its quadrature (imaginary) conductivity, which is not very sensitiveto pH and salinity (NaCl) in the 100 Hz to 45 kHz frequency range. For lower frequencies, the suddenincrease of the quadrature conductivity at the highest salinities was explained by considering coagulationof Na-Mt particles.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000410464100117
%R 10.1016/j.jcis.2017.06.071
%U https://juser.fz-juelich.de/record/834655