Effect of thermal treating temperature on characteristics of silver-doped titania

The silver-doped titania antibacterial agent was synthesized by mixing silver nitrate and the precursor of titania. Effects of thermal treatment on the properties of the silver-doped titania powders were investigated by thermal gravimeter/differential thermal analyzer(TG/DTA), scanning electron microscope(SEM), and X-ray diffractometer(XRD), respectively. The results show that the anatase phase forms in titania when the powder is calcined at 400 ℃. With the increase of the calcination temperature from 400 to 700 ℃ , the grains of titania agglomerate and the particle size increases from 14 to 23 nm, and the specific surface area decreases from 63 to 38m2g. As the powder is calcined at 700 ℃, titania starts to transform from anatase to rutile phase. The release rate of silver ion of powder treated at the relatively low temperature is larger than that of powder treated at the relatively high temperature. The antibacterial tests show that the antibacterial activity of silver-doped titania powders is excellent against E.coli and S. aureus, and the antibacterial activity of powders weakens with the increase of the calcination temperature.