Electrokinetic behavior of colloidal particles with thin ionic double layers

Abstract

The phenomenological equations that govern the nonequilibrium behavior of the ionic diffuse double layer surrounding an isolated, charged colloidal particle are considered. An approximate solution is constructed that is valid when the ratio of the Debye length to the characteristic particle dimension is small. This solution is applicable to a particle that is subjected to an external perturbation composed of an arbitrary linear combination of steady, axisymmetric electrical, hydrodynamical, or concentration gradient fields. Hence, this analysis provides a unified approach t o the treatment of the entire class of admissible problems in the thin double layer approximation. Specific applications are shown to the problems of electrophoresis and dilute shear viscosity of a suspension of uniform, noninteracting spherical colloidal particles. Comparison with the numerical results of previous investigators shows that the solutions are accurate over much of the parameter range of practical interest in colloidal suspensions. The role of the zeta potential and the mobilities, valences, and concentrations of the dissolved ions on electrokinetic phenomena are examined.

Use of Inorgano-Organo-Clays in the Removal of Priority Pollutants from Industrial Wastewaters: Structural Aspects

“…Hachisu (1984) and Horikawa et al (1988) reported that the zeta potential, if measured under similar particle size and solution conditions, is a valid basis for such a comparison. In addition, Natarajan and Schechter (1987) recognized that in the limit of a thin double layer, significant deviations from Smoluchowski's theory occur only at fairly large zeta potentials. The greatest zeta potential recorded in the present study was only 45 mV.…”

Deep Electrophoretic Penetration and Deposition of Ceramic Particles inside Porous Substrates: I . Analytical Model

“…The motion of a single particle under the effect of electrophoretic forces has first been addressed by Smoluchowski (1918) and subsequently by many others (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Smoluchowski predicted that a rigid spherical particle possessing an electric double layer and embedded in an unbounded flow field would be forced to move if subjected to an electrical potential gradient.…”