Electrophoretic mobility of spherical colloidal particles in concentrated suspensions

A general mobility expression is derived for a swarm of identical spherical colloidal particles in concentrated suspensions on the basis of S. Kuwabara's cell model [J. Phys. Sec. Japan 14, 527 (1959)]. This expression, which is a function of kappa a (kappa = Debye-Huckel parameter and a = particle radius) and the particle volume fraction (or the porosity), tends to a mobility expression derived by S. Levine and G. H. Neale [J. Colloid Interface Sci. 47, 520 (1974)] for low zeta potentials and to that derived by M. W. Kozak and E. J. Davis [J Colloid Interface Sci. 129, 166 (1989)] for the case of nonoverlapping double layers. A simple approximate mobility expression is derived with relative errors less than 4%. (C) 1997 Academic Press.