Colloido-chemical characteristics of zinc oxide in electrolyte solutions

摘要

The electrosurface characteristics (total surface charge, electrokinetic potential, and positions of the point of zero charge and isoelectric point) of zinc oxide have been comprehensively studied as depending on pH and background electrolyte (NaCl) concentration. The constants of surface reactions and the adsorption potentials of potential determining of background electrolyte ions have been obtained in terms of the 2pK-model. The aggregation stability of aqueous zinc oxide suspensions has been studied in a wide range of concentrations of 1: 1 and 1: 2 electrolytes, and the threshold of sol coagulation has been found. Within the framework of the DLVO theory, the interaction energy between ZnO particles has been calculated as a function of the interparticle distance. It has been demonstrated that the experimental data can be qualitatively described in terms of the classical DLVO theory, which takes into account only ion-electrostatic and molecular (dispersion) forces of interparticle interaction.