Determination of the temperature dependence of Titanium(IV) hydrolysis and complexation constants in aqueous sulfuric or chlorhydric solutions

Thermohydrolysis in aqueous acidic (sulfuric or chlorhydric) solutions is one of the main processes to produce titania particles. Nevertheless, a survey of available thermodynamic constants shows discrepancies between authors, even at room temperature. In addition, the temperature dependence of thermodynamic constants is seldom studied, making it hazardous to predict the speciation and supersaturation at usual thermohydrolysis temperatures. Here we propose a simple method, based on solubility measurements at 25 °C and at 80 °C, to select the best set of constants at room temperature among those existing in literature as well as the best extrapolation method of these constants to thermohydrolysis temperature.