By Sunil Bhardwaj


There are two main electrical properties of Colloidal Solutions:

Cataphoresis: Colloidal particles carry an electric charge and therefore, move towards the oppositely charged electrode when the solution is placed under the influence of an electric field. This migration of colloidal particles under the influence of electric field is called cataphoresis. The type of charge on sol particle can be determined by noting the direction of their motion. The important applications of cataphoresis are:
Removal of colloidal gases.
Removal of dirt particles.
Electro-deposition of rubber.

Electro-Osmosis: A sol is electrically neutral. This reveals that dispersion medium carries an equal but opposite charge to the dispersed particles. If the dispersed phase sol is kept stationary by some suitable means, it is observed that the dispersion medium itself begins to move under the influence of an electric field. This motion of the dispersion medium under the influence of an electric field is called electro-osmosis