A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acid...A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.展开更多
Ultra fine SO 2- 4/TiO 2-SiO 2 complex catalysts were synthesized by the one-step calcination method,which used titania sulfate and white carbon as raw materials and polyvinyl alcohol as dispersing agent. Catalysts ar...Ultra fine SO 2- 4/TiO 2-SiO 2 complex catalysts were synthesized by the one-step calcination method,which used titania sulfate and white carbon as raw materials and polyvinyl alcohol as dispersing agent. Catalysts are characterized by XRDIRTDA and BET. Different preparation factors were discussed.The catalysts consisting of SO 2- 43.4% and TiO 2∶SiO 2=1∶6 showed excellent reaction activity and stability for the photocatalytic degradation of phenol.Controlling calcination temperature and time (450℃,2h) could avoid or diminish the formation of Ti-O-Si bond and obtain higher V g and better dispersivity of TiO 2 on the surface of SiO 2.The kinetic study on photocatalytic degradation of phenol with the complex catalysts in a suspension system under 40W UV-lamp showed that apparent rate constant k conformed to a zero-order kinetic model at initial concentration <100mg·L -1 and increased with increasing pH value of phenol solution up to pH=12.When pH=10,k=3.32×10 -1 mg·L -1 ·min -1 . Solar photocatalytic experiment also gave good results.展开更多
Based on the existing form of Zn2 Si O4 in willemite, the chemical precipitation method was used to synthesize Zn2 Si O4.Through the orthogonal experimentation, the reaction conditions of melten Na OH decomposing Zn2 ...Based on the existing form of Zn2 Si O4 in willemite, the chemical precipitation method was used to synthesize Zn2 Si O4.Through the orthogonal experimentation, the reaction conditions of melten Na OH decomposing Zn2 Si O4 were optimized, and the optimal experimental conditions include reaction temperature of 400 °C, reaction time of 4 h, and alkaline-to-ore molar ratio of 20:1.Based on the optimized experiment, on-line detection for the alkali leaching was made by using Raman spectroscopy; XRD was used to analyze the structure of water leaching residue, to explore the reaction mechanism of Na OH decomposing Zn2 Si O4. The results show that during the reaction process, the Si — O bond in Si O4 is destroyed, and the Na OH inserts itself into the silicate lattice,producing an immediate Na2 Zn Si O4 product. After the alkali leaching process, Zn2+ can be separated from the Si O4 array, which can be released out of the silicate in the form of ZnO.展开更多
文摘A series of SO 2- 4/TiO 2 SiO 2 catalysts with different mass fractions of SiO 2 were prepared by sol gel method. The effect of adding SiO 2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO 2- 4/TiO 2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO 2, leading to the obvious increase on photocatalytic activity of SO 2- 4/TiO 2 SiO 2 catalysts and mineralization ratio of bromomethane. Comparing with SO 2- 4/TiO 2, the acidic strength and anti moisture ability of SO 2- 4/TiO 2 SiO 2 catalyst were decreased.
文摘Ultra fine SO 2- 4/TiO 2-SiO 2 complex catalysts were synthesized by the one-step calcination method,which used titania sulfate and white carbon as raw materials and polyvinyl alcohol as dispersing agent. Catalysts are characterized by XRDIRTDA and BET. Different preparation factors were discussed.The catalysts consisting of SO 2- 43.4% and TiO 2∶SiO 2=1∶6 showed excellent reaction activity and stability for the photocatalytic degradation of phenol.Controlling calcination temperature and time (450℃,2h) could avoid or diminish the formation of Ti-O-Si bond and obtain higher V g and better dispersivity of TiO 2 on the surface of SiO 2.The kinetic study on photocatalytic degradation of phenol with the complex catalysts in a suspension system under 40W UV-lamp showed that apparent rate constant k conformed to a zero-order kinetic model at initial concentration <100mg·L -1 and increased with increasing pH value of phenol solution up to pH=12.When pH=10,k=3.32×10 -1 mg·L -1 ·min -1 . Solar photocatalytic experiment also gave good results.
基金Project(2007CB613603)supported by the National Basic Research Program of ChinaProject(51204037)supported by the National Natural Science Foundation of China
文摘Based on the existing form of Zn2 Si O4 in willemite, the chemical precipitation method was used to synthesize Zn2 Si O4.Through the orthogonal experimentation, the reaction conditions of melten Na OH decomposing Zn2 Si O4 were optimized, and the optimal experimental conditions include reaction temperature of 400 °C, reaction time of 4 h, and alkaline-to-ore molar ratio of 20:1.Based on the optimized experiment, on-line detection for the alkali leaching was made by using Raman spectroscopy; XRD was used to analyze the structure of water leaching residue, to explore the reaction mechanism of Na OH decomposing Zn2 Si O4. The results show that during the reaction process, the Si — O bond in Si O4 is destroyed, and the Na OH inserts itself into the silicate lattice,producing an immediate Na2 Zn Si O4 product. After the alkali leaching process, Zn2+ can be separated from the Si O4 array, which can be released out of the silicate in the form of ZnO.
