Electokinetic and adsorption properties of different titanium dioxides at the solid/solution interface

Abstract

Six samples of titanium dioxide of different phase compositions and specific surface areas have been characterized by XRD, Ramanand FTIR spectroscopy, adsorption of nitrogen, electrophoresis. Adsorption of Zn(II) ions at the TiO 2 /NaCl aqueous solution interface as well as the effect of adsorption on the structure of electrical double layer have been studied. The influence of ionic strength, pH and presence of ions on the adsorption of Zn(II) ions at the TiO 2 /NaCl solution interface have also been investigated. The zeta potential, surface charge density, parameters of adsorption edge pH50% and δpH10-90% for different concentrations of basic electrolyte have been determined. Studied unpurified samples showed lower values of isoelectric point pHiep compared with literature data due to the presence of anion impurities. The antibate dependence between pHiep values and particle size has been established. Adsorption of Zn(II) ions using monophase samples is completed at a lower pH than for the biphase TiO 2 . Appearance of the point CR3 is associated with the charge turnover from positive to negative at high values of pH and formation of Zn(OH) 2 . © Versita Sp. z o.o.