The influence of temperature, pH and the presence of adsorbed fluoride on the surface charge at the γ-Al2O3 /aqueous solution interface has been investigated by means of potentiometric titration method and study of equilibrium adsorption of fluoride ions to elucidate the nature of sorbent surface, the different species of sites, to delineate the mechanism of fluorine adsorption. Such data can be available only on the base of adsorption studies at increased concentrations of adsorbate. The surface charge density was measured through the method of continuous potentiometric titration at three ionic strengths and 2 temperatures – 20 and 400C. The dependence of obtained pH of point of zero charge on the reciprocal temperature is linear which allowed estimating the standard enthalpy and entropy of the process of transition of protons and hydroxyl groups from the surface into the bulk solution and inversely.