Hydrothermal behavior of titanium(IV) sulfate solutions

The effect of temperature (50 and 75°C) on the viscosity and stability of titanium(IV) sulfate solutions is demonstrated. The changes in the speciation of Ti(IV) in these solutions under the same conditions are reported. The structural transformations of the titanium(IV) sulfate complexes include their conversion into hydroxo(oxo) complexes, the association of the latter, and the growth of the association species up to the size of colloidal particles. This behavior is practically independent of the composition of the initial solution. There can be only variations in the rates of the above hydrolysis stages and, accordingly, in the particle size of the resulting solid phase. By regulating the thermal treatment conditions for titanium(IV) solutions, it is possible to synthesize precursors consisting of nanosized particles (5–30 nm) and having a developed surface morphology. This provides means to obtain titanium dioxide with preset properties.