Study On Preparation Of Silver Based Photocatalysts And Its Photocatalytic Effect On Pollutant In Water Under Visible Light Irradiation

In recent years, the preparation of photocatalysts with visible light response and photocatalytic activity have been one of the most hot topics. The silver based photocatalysts were prepared such as photosensitizatized Ag/TiO2, Ag3PO4/TiO2, Ag/ZnO microspheres, Ag/cationic resin, Ag3P04/anion-exchange resin and Ag3PO4/permutite in this paper. The photocatalytic effect on organic pollutant or heavy mental ion in water had been investigated by using the photocatalysts.The Ag/TiO2 and Ag3PO4/TiO2 composite photocatalysts were prepared by hydrothermal, sol-gel and chemical deposition methods. The synthetic samples were characterized by XRD and TEM. After Ag/TiO2 soaked in chlorophyl extract,the photosensitizatized Ag/TiO2 compound were prepared. The visible light response ability of the Ag/TiO2 and photosensitizatized Ag/TiO2 was analyzed by UV-Vis DRS.Irradiations were performed with UV light and visible light, respectively, and hexavalent chromium ion solution was used as object.The photocatalytic activity of Ag/TiO2 and photosensitizatized Ag/TiO2 was studied. The results showed that the photosensitized Ag/TiO2 had better photocatalytic activity. The photocatalytic effect on formaldehyde was studied by using Ag3PO4/TiO2 and Ag3PO4 as catalysts under visible light, respectively.The result showed that the Ag3PO4/TiO2 compound had better photocatalytic activity. In the catalytic reaction process, the formaldehyde was firstly oxidized to formic acid, then decomposed into carbon dioxide and water.Carbon microspheres were successfully synthesized by using glucose, urea and zinc salt as the raw materials at low-temperature, and then cancinated at 500℃ for 3 hours to get zinc oxide microspheres. The carbon microspheres were soaked in silver nitrate solution, and then cancinated at 500℃ for 3 hours to get Ag/ZnO microspheres. The samples obtained was characterized by XRD, SEM and EDS. Effect on degradation of dichloromethane was investigated under the visible light by using ZnO microspheres and Ag/ZnO microspheres as photocatalysts, respectively. The results showed that the Ag/ZnO microspheres had better photocatalytic effect on dichloromethane.The dichloromethane was directly decomposed into carbon dioxide and hydrogen chloride.The Ag/cationic resin, Ag3PO4/anion-exchange resin and Ag3PO4/permutite composites were prepared by ion exchange process and chemical deposition methods in this paper. The samples were characterized by SEM, XRD, EDS,XPS. The effect on photocatalytic degradation of methyl orange solution was studied by using Ag/cationic resin compound as photocatalysts under UV light and visible light, respectively. The results showed that the Ag/cationic resin compound prepared by photoreduction method had better photocatalytic activity and and the photocatalyst could be recycled for several times. The effect on photocatalytic degradation of methylene blue solution were investigated by using Ag3PO4/anion-exchange resin and Ag3PO4/permutite composite as photocatalysts under UV light and visible light, respectively. The results showed that Ag3PO4/anion-exchange resin composite had better photocatalytic activity and the photocatalyst could be recycled for several times.