An analysis of electrophoresis of concentrated suspensions of colloidal particles

Journal Article · Thu Jul 15 04:00:00 EDT 1999 · Journal of Colloid and Interface Science

DOI:https://doi.org/10.1006/jcis.1999.6282· OSTI ID:680104

Johnson, T J; Davis, E J ^[1]

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1. Univ. of Washington, Seattle, WA (United States). Dept. of Chemical Engineering

An analysis of the electrophoretic motion of charged colloidal particles in a concentrated suspension is developed to predict the electrophoretic mobility of the particles and the electrical conductivity of the suspension. The analysis is based on a unit cell model that takes into account particle-particle hydrodynamic interactions and includes relatively thick electric double layers. The fluid motion in the unit cell is treated by writing the relevant Navier-Stokes equation in terms of the stream function and vorticity. The governing equations were then solved by a finite-difference method. The calculated electrophoretic mobilities are in agreement with prior analytical solutions for moderately concentrated suspensions, and the theory reduces to the result of O`Brien and White for low to moderate zeta potentials and dilute suspensions and to the classical result of Smoluchowski for thin double layers and dilute suspensions. A parametric study shows that the electrical conductivity of the suspension relative to a free electrolyte solution is affected by the counterion to co-ion diffusivity ratio, the double-layer thickness, and the volume fraction of particles. For a dispersion of moderately charged particles (moderate zeta potentials) with thick double layers, the numerical model predicts the electrical conductivity in agreement with experimental values reported in the literature. This research was initiated to explore the removal of colloidal coal and clay from lake water and process water contaminated by coal-washing facilities.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG22-95PC95209
• OSTI ID: 680104
• Journal Information: Journal of Colloid and Interface Science, Journal Name: Journal of Colloid and Interface Science Journal Issue: 2 Vol. 215; ISSN 0021-9797; ISSN JCISA5
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
CLAYS
COAL FINES
COLLOIDS
ELECTRIC CONDUCTIVITY
ELECTROPHORESIS
MATHEMATICAL MODELS
PARAMETRIC ANALYSIS
REMOVAL
SUSPENSIONS
WASTE WATER
WATER TREATMENT