Influence of inorganic cations on -potential of alumina dispersions

Abstract

The -potential of alumina dispersions were measured at two concentrations of monovalent electrolyte. Li+, Na+ and K+ were the investigated counterions, while the co-ion was always Cl-. In comparison with the results of -potential as a function of pH of pure Al2O3 without any added salts, the shift of isoelectric point (IEP) caused by added salts was observed. The values of IEP depend on the used counterion and on the concentration of the electrolyte which was added to dispersion of Al2O3. The specific adsorption of cations shifts the IEP to higher values, while the specific adsorption of anions shifts the IEP to lower values.