Titre :
|
Effect of aqueous phase properties on clay particle zeta potential and electro-osmotic permeability : implications for electro-kinetic soil remediation processes
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Auteurs :
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L. Vane ;
G. Zang
|
Type de document :
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article/chapitre/communication
|
Année de publication :
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1997
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Format :
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p.1-22
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Langues:
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= Anglais
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Catégories :
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CHIMIE
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Mots-clés:
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ARGILE
;
POTENTIEL HYDRIQUE
;
PERMEABILITE
;
PH
|
Résumé :
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The influence of aqueous phase properties (pH, ionic strength and divalent metal ion concentration) on clay particle zeta potential and packed-bed electro-osmotic permeability was quantified. Although pH strongly altered the zeta potential of a Georgia kaolinite, it did not significantly change that of a Wyoming bentonite. The zeta potential for the kaolinite ranged from + 0.7 mV at pH = 2 to -54 mV at pH = 10 (0.01 M KCl) while the bentonite zeta potential changed by only 5 mV(-31 to -36 mV) over the same pH range. For both clays, ionic strength was found to have a weak effect while divalent cations made the zeta potential markedly more positive. Charge reversal was observed for kaolinite at 100 ppm Pb2+ (pH = 5) with a background ionic strength of 0.01 M KCI and only 10 ppm Pb2+ with a background of 5 X 10(-4) M KCl, A theoretical relationship between the electro-osmotic permeability coefficient for packed clay beds and particle zeta potential was developed and experimentally verified for kaolinite. For example, both the electro-osmotic permeability coefficient and particle zeta potential were found to be three times greater at pH = 5 than at pH = 3. As a result, rapid zeta potential analyses can be used to predict electro-osmotic performance for expected site conditions as well as to select electrolyte control strategies to optimize an electro-kinetic soil remediation process.
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Source :
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Journal of hazardous materials, vol 55
|