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O: Fachverband Oberflächenphysik
O 34: Solid-Liquid Interfaces: Reactions and Electrochemistry - Experiment II
O 34.2: Talk
Tuesday, March 21, 2017, 11:00–11:15, HSZ 101
Low-frequency conductivity of clay suspensions: Electrokinetic potentials, surface conductance and counterion mobility — •Christian Weber1, Helge Stanjek2, and Markus Valtiner1 — 1Institut für Physikalische Chemie, TU Freiberg, Leipzigerstrasse 29, 09599 Freiberg — 2Ton- und Grenzflächenmineralogie, Bunsenstrasse 8, 52072 Aachen
This work presents results on the low-frequency electric conductivity of kaolinite dominated clay suspensions. The theoretical interpretation of conductivity data is guided by the theory of O'Brien & Ward [1] which accounts for the non-spherical particle shape and surface conductance. Essential outcomes of the conductivity experiments are the surface conductance and electrokinetic potential. Alongside with the conductivity experiments the surface charge density of the particles has been measured under similar conditions. A correlation of the surface conductance and the surface charge density allows to estimate tangential counterion mobilities in the Stern layer and a consistency check of the conductivity interpretation.
References
[1] O'Brien R. W. & Ward D. N. (1988) The electrophoresis of a spheroid with a thin double layer. Journal of Colloid and Interface Science, 121(2), 402-413.