Abstract
Over a wide range of pH, the electrokinetic potentials of eighteen oxides have been measured in solutions of KCl, CaCl2 and AlCl3. The adsorption of K+, Ca++ ions on the oxides is physical in nature. The isoelectric points of all oxides in presence of 1 m mole/L of AlCl3 solution are constant at 8.25 +/- 0.25. That is an indication for the precipitation of Al(OH)3 and complete surfaces coverage on the oxides by Al+3 ions. The non-indifferent electrolytes do not exhibit a certain behaviour, due to the different relative change in solubility and to the different formation of metal hydroxides which depend on the pH of the medium.