Approximate expression for the electrophoretic mobility of a spherical colloidal particle in a solution of general electrolytes

An approximate analytic expression is derived for the electrophoretic mobility of a charged spherical colloidal particle in a solution of general electrolytes on the basis of an approximation method by [Ohshima et al., J. Chem. Soc. Faraday Trans. 2, 79 (1983) 1613]. This expression, which takes into account the relaxation effects, is applicable for all values of zeta potential at large κa (κa ≥ ca. 30), where κ is the Debye–Hückel parameter and a is the radius of the particle core.