Superfast electrophoresis of ion-exchanger particles

Abstract

It has been shown that the electrophoretic mobility of large ion-exchanger particles (diameter, 250–1000 μm) or fibres (length, 100–1000 μm) in strong electric fields (100–1000 V cm −1) exceeds the electrophoretic mobility values typical for non-conducting particles by one or two orders of magnitude. This phenomenon was called “electrophoresis of the second kind” or “superfast electrophoresis”. The mobility of such particles depends on the conductivity ratio between the particles and medium and increases linearly with the electric field gradient and the particle size. This is in contrast to classical electrophoresis which does not depend on these parameters. The effect of electrolytes and pH on the electrophoretic mobility in strong fields is due to the change in the conductivity ratio mentioned above. Changes in the electric double layer parameters do not affect the mobility. Electrophoresis of the second kind is due to the interaction of a strong electric field with the space charge near the surface of unipolar conducting particles. It occurs only when the conductivity of particles exceeds the conductivity of the medium. New methods to observe this phenomenon were developed.