Ti(IV) hydrolysis constants derived from rutile solubility measurements made from 100 to 300°C

Using a Au–Ir hydrothermal reaction cell and dilute buffer solutions to control pH, the isobaric solubility of rutile (TiO2) was measured over a broad pH range from pH 1 to 13 between 100 and 300°C. The solubility data were regressed to derive the cumulative and stepwise hydrolysis constants for Ti(IV) in aqueous solution. The data were accurately modeled using the hydrolysis species: Ti(OH)+3, Ti(OH)4(aq) and Ti(OH)−5. The following cumulative (Ks3, Ks4, Ks5) hydrolysis constants (log K and error, reactions written with respect to the solid oxide) and stepwise (K34, K45) hydrolysis constants (log K and error) were determined by regression: image