SUPERFAST ELECTROPHORESIS OF ELECTRON-TYPE CONDUCTING PARTICLES

The features of concentration polarization caused by electric current through a unipolar conductive particle are considered. The peculiariti es of the formation of an induced space charge near a particle with el ectron-type conductivity are analysed. It has been shown that the theo retical values of electrophoretic velocity for these particles are ess entially smaller than those calculated for particles with ion-type con ductivity.A new method to observe the superfast electrophoresis is dev eloped. The electrophoretic velocity of graphite and activated carbon particles of different size (diameter, 200-500 mu m) displaced in dist illed water and electrolyte solutions in strong electric fields (100-5 00 V cm(-1)) was measured. It is shown that, in contrast to classical electrophoresis, the electrophoretic mobility of such particles increa ses with the particle size and the external field strength. The experi mental and theoretical results are compared. The discrepancy between t heory and experiment is analysed. (C) 1998 Elsevier Science B.V. All r ights reserved.