RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics

The detailed electrokinetic and coagulation behavior of TiO₂ and Al₂O₃ hydrous oxide colloids, is reported as a function of pH and indifferent electrolyte concentration. The isoelectric point values for TiO₂ (pH 5.9) and Al₂O₃ (pH 8.9) were obtained by both techniques.

Comparison of the observed coagulation rates with those calculated on the basis of observed ζ-potentials using the Derjaguin—Landau—Verwey—Overbeek theory supports the general validity of the theory for oxide colloids. Specifically rapid coagulation, whether induced by pH or KNO₃ concentration changes, occurs at |ζ| ⩽ 14 ± 4 mV in all systems.