以硫酸钛(Ti(SO4)2)为前驱物水解得到超细球形TiO2.研究了水解过程中前驱物浓度和体系温度对水解速率的影响,并对实验值进行了拟合,得到水解TiO2的质量分数与水解时间呈良好的指数关系,根据Avrami方程进一步验证了拟合的可靠性.分析了水解介质的影响作用,确定介电常数和zeta电位也是影响水解速率的重要因素,因此可通过改变溶剂成分来调节介电常数和zeta电位,从而达到控制Ti(SO4)2水解速率的目的.实验结果表明,Ti(SO4)2水解制备TiO2的过程中,较低的前驱物浓度,较高的水解温度和合适的溶剂体系有利于得到粒径分布窄、分散性好的TiO2.
Spherical titania was prepared by a hydrolysis method of titanium sulfate as the precursor. The effects of the precursor concentration and temperature on the hydrolysis rate were discussed. Results showed that an exponential relationship existed between the mass fraction of titania and hydrolysis time. These results were confirmed by the Avrami equation. The effect of the medium on the hydrolysis rate was also discussed. The hydrolysis rate could be controlled by adjusting the dielectric constant and the zeta potential. By analysis of the preparation procedure of the spherical titania and the kinetics thereof, we conclude that a low precursor concentration, high hydrolysis temperature, and adaptive medium are the key points for the preparation of high quality titania with narrow particle size distribution and good dispersibility.