Photocatalytic Degradation of Dye Wastewaters by Functional Silver-loaded and Functional Acid nanotubes

• Main Authors: Jun-Qi Xiao, 肖俊祺
• Other Authors: Kuen-Song Lin
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/84932626172204736249

碩士 === 元智大學 === 化學工程與材料科學學系 === 105 === Nowdays, environmental depravation comples us to develope new and efficient approaches that can eliminate more and more kinds of pollutants, espeicially large quantity of non-biodegradable contaminants in wastewater. Among the existing strategies, semiconductor photocatalysis is highly expected to be an ideal “green” technology. It has been widely applied in the field of environmental pollution protection and energy conversion. How to effectively deal with dye wastewater has been attract most of attention from all over the world. In 1972, TiO2 photocatalyst was discoved and it can be use the solar energy to degrade the dye without causing secondary pollution. However, due to the larger band gap of TiO2, it is only can induced by the ultraviolet light, making people strive to find new catalysts to good use of solar energy. Recently, silver-based photocatalysts have attracted considerable attention for the photodegradation of organic pollutants or splitting water. In this study, a facile process for synthesizing stable and hollow plasmonic photocatakyst was investigated. Preparation of Ag-based tubular photocatalytic nanomaterial and their application in photodegradation of pollutants were also performed. The mechanism, morphology, photoelectric properties and photocatalytic performance of the synthesized catalyst were studied using XRD, XPS, FE SEM-EDS, HR-TEM, PL, Uv-vis, and DRS. The specific contents of this paper are as follows: 1.In the synthesis, metallic silver was first synthesized by using presynthesized Cu as a template. Ag@AgCl photocatalyst was then fabricated from the reaction between Ag and FeCl3•6H2O at room temperatature. The catalysts were characterized by XRD, XPS, FE-SEM, EDS and HR-TEM. The photocatalytic activity of Ag@AgCl was investigated to degradation RhB and used visible light to induce the photocatalytic reaction. Its can be completely degraded rhodamine B at 35 min. The degradation efficiency indicates that the high activity of the catalyst is due to the surface plasma resonance absorption of Ag nanoparticals and the internal and external double layer surface provided by the tubular hollow structure, which enhanced the photocatalyst photocatalytic degradation efficiency. 2.Ag@AgCl@AgBr series catalysts were fabricated from the reaction between KBr and Ag@AgCl at room temperature. The catalysts were characterized by XRD、FE-SEM, EDS、XPS、PL、UV-vis、HR-TEM and DRS. The optimum photocatalytic efficiency of AB-2 heterostructures for the degradation of RhB and Red Acid I under visible light irradiation was can be degrade about 98.76% and 95.37% at 45 min, respectively. The radical trap experiments showed that the degradation of RhB and Red Aicd I was driven by the participataion of superoxide radical and the action of holes. It also can be found AB-2 catalyst have long-term stability. Further studies have found that AgCl and AgBr semiconductor catalysts can be effectively coupled to form heterogeneous sections, thus enhance the separation and transfer efficiency of photo-induced electron-hole pairs, then enchance the photocataytic efficiency. And also due to the SPR effect and the catalyst inner and outer double layer surface structures, which makes the AB-2 catalyst haves strong visible photocatalytic efficiency. 3.Ag@AgCl@AgI series catalysts were fabricated from the reaction between NaI and Ag@AgCl at room temperature. The catalysts were characterized by XRD、FE-SEM, EDS、XPS、PL、UV-vis、HR-TEM and DRS. The optimum photocatalytic efficiency of AI-2 heterostructures for the degradation of RhB under visible light irradiation was can be degrade about 91.76% at 45 min. The radical trap experiments showed that the degradation of RhB and Red Aicd I was driven by the participataion of superoxide radical and the action of holes, the same with AI-2. Further studies has found that AgCl and AgI semiconductor catalysts can be effectively coupled to form heterogeneous sections, thus enhance the separation and transfer efficiency of photo-induced electron-hole pairs, then enchance the photocataytic efficiency. And also due to the SPR effect and the catalyst inner and outer double layer surface structures, which makes the AI-2 catalyst have strong visible photocatalytic efficiency.