Contained Silver Titanium Dioxide Composite Powder Preparation And Antibacterial Properties Characterized

Researches and applications of the inorganic antibacterial reagents have been deeply conducted because of their advantages in safety, permanence, broad-spectrum. Among the antibacterial reagents, light catalyst of titanium dioxide and silver are widely used. Ultraviolet ray is necessary for titanium dioxide application and this makes its antibacterial performance weaker. Researches on silver antibacterial products are aimed at adding silver ions into zeolite, phosphate, soluble glasses to carry on antibacterial function. But the silver ions release is so great in initial development stage that the color of products is apt to change and the utility is limited up to now. Different inorganic antibacterial agents are compounded to overcome these shortcomings and strengthen its antibacterial activation.Adding silver salt in the procedure of making nano-powder of titanium dioxide is chosen after this study. The purpose of this study is to develop a new type of antibacterial agent by dissolving silver salt into the powder to achieve the slow release of silver. The technological parameters such as temperature, time, pH value that influence the silver contents of titanium dioxide precursor are investigated. The influences of heat treating temperature, silver content on antibacterial performance and the color of products are studied. XRD, SEM and EDS are used to check the products. The antibacterial performs of the powder are examined by minimum inhibitory concentrations and restrain fungus. The results show that the silver content in precursor is small at high or low reaction temperature. The pH value of the solution has little effect on silver content, but strongly influences the color of the products. The silver content in precursor increases after long period of reaction time. Two types of anatase crystal precursor are obtained after thermal treatment at the temperature under 800℃. The particle size of crystal grain increases at high heat treating temperature. Silver sulphate shows the best antibacterial performance, silver phosphate takes the second place and chlorine silver is the worst after treated under 600℃. After treated over 600℃, the antibacterial performance of chlorine silver drops fastest, thenis silver sulphate, silver phosphate is able to bear high temperature treatment. The temperature of thermal treatment influences the color of products. The color of powder is dirtied when the treating temperature is very low or high. The amount of silver loaded does not influence crystal type of titanium dioxide. The increase of silver quantity appears the diffraction peak of the silver gradually. The antibacterial performance increases and the color dimmed with more silver content in the powder. The grain gets small and the color of powder is meliorated and whitens when phosphoric acid applied. The thinning degree of straight titanium was higher than the metatitanic acid as precursor, but its quantity of release is smaller than the metatitanic acid at the first time. After soaking, antibacterial performance of the metatitanic acid drops relatively heavy. The titanium dioxide/silver phosphate compound powders can tolerance light irradiation.