Study on the behavior of sulfur in hydrolysis process of titanyl sulfate solution

The existing forms of sulfur in hydrolysis process of titanyl sulfate solution were studied. Also the effects of sulfur on crystal structure, crystallite size and crystal phase transition of the hydrated titanium dioxide(TiO2·H2O) and titanium dioxide (TiO2) were conducted. The analysis and methods of thermogravimetric-differential scanning calorimet (TG-DSC), energy dispersive spectrometer (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV–Vis diffuse reflectance spectra and Raman spectroscopy were employed to characterize. The results indicated that the sulfur was present in the form of SO42− ions in the hydrolysate of titanyl sulfate solution, and a portion of SO42− ions were combined on the surface of hydrated titanium dioxide by chemical adsorption in the forms of inorganic chelating bidentate coordination and covalent sulfate coordination, the residual SO42− ions were adsorbed on the surface of hydrated titanium dioxide by physical adsorption. The chemical adsorption of SO42− ions were conducive to the formation and stabilization of anatase, which changed the crystal structure, and hindered the transformation of the anatase into rutile. The results of Raman spectroscopy showed that the sulfur was dissociated in the forms of SO42− and HSO4− ions during the hydrolysis of titanyl sulfate solution. The characteristic peak at 1004 cm−1 corresponding to a new complex has been observed, which was composed of SO42− and hydrated titanium complex ions through the bonding on the surface. In basis of the above experimental results, the hydrolysis process of titanyl sulfate solution was illustrated from the microstructure with 3D atlas.