Study on degradation of Bisphenol-A using nitrogen and lanthanum co-doped TiO2 photocatalyst under solar light irradiation

• Main Authors: Wei-Fu Wang, 王維甫
• Other Authors: 謝永旭
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/46153800877833582909

博士 === 國立中興大學 === 環境工程學系所 === 103 === Environmental hormone is one kind of chemical which structure is like biological hormone structure, and could be intaken by organism through air, water, food, or other pathway. Only very small amount of environmental hormone can interfere with the synthesis of the body''s hormonal system, secretion, and binding reactions, thereby affecting the organism''s, reproduction, development, growth, and other physiological reaction constant. Bisphenol A (BPA) is an estrogenic effect environmental hormone. It is primarily monomer material of polycarbonate and epoxy resins. According to a recent study, it pointed out that many countries around the world have been finding out trace amounts of bisphenol A in effluents of wastewater treatment plant and surface water. Therefore, how to remove the bisphenol A in water has become the urgent subject. In this study, different ratio nitrogen modified, lanthanum modified and nitrogen- lanthanum co-doped titanium dioxide photocatalyst were prepared by Sol-Gel method for degradation of environmental hormone BPA. All kinds of catalyst test parameters were measured for the results as a basis to find optimum operating conditions in sunlight system. All results are in order to be used in a real field in future. Research by field emission scanning electron microscope (FE-SEM), specific surface area analyzer (BET), high-resolution X-ray diffraction instrument (HRXRD), electron spectroscopy for chemical analysis (ESCA), UV/visible absorption spectroscopy (UV/Vis) and zero potential instrument for measuring surface characteristics of photocatalyst analyzed and discussed the differences between all photocatalyst. The analysis showed that 0.1 NT + 0.025 LaT catalyst is the most suitable in surface characteristics for the photocatalytic reaction conditions. Titania catalyst surface crystal size is about 10 nm; tiny particles reflect the excellent specific surface area (78.7 m2 / g); the appropriate proportion of Anatase and Rutile can absorb visible light as well as taking into account the catalytic activity. Powder catalyst photolysis experiments are used visible or ultraviolet light as a light source in the laboratory, and all of modified catalyst powders were determined optimal conditions by BPA removal and mineralization rate. The results show that whether type of lighting, 0.1 NT + 0.025 LaT catalyst powders are the best of the mineralization rate to under acidic conditions; adding 0.5 g of catalyst reactive better; the lower the BPA concentration, the higher the proportion of removal. So the powder photolysis system can also be applied to remove BPA in natural water. Fixed catalyst in the sun light photocatalytic reaction, still 0.1 NT + 0.025 LaT fixed state catalyst has the best removal efficiency. 0.1 NT + 0.025 LaT at pH 4 conditions BPA removal up to 33.5 %, while the mineralization rate is up to 33.6 %. It shows that 0.1 NT + 0.025 LaT fixed modified catalyst is optimal proportion of sunlight degradation. Integration all optimal reaction conditions of sunlight degradation: catalyst amount to 0.1 NT + 0.025 LaT Fixed income catalyst impregnated with six time which is the most suitable catalyst load of this system; the higher the initial concentration of BPA removal capability will be improved, the optimal initial concentration of 20 μM in this study; when water containing NO32- ions, BPA removal capability will also be improved. Finally, the fixed catalyst reacts after five times, it can still maintain a certain activity and helps catalyst recycling. In this study, all tests and the sunlight degradation experiment, many expressed that co-doped catalysts has the potential to sunlight degradation react with the appropriate equipment. It will help to remove Bisphenol A of water environment, and the results of this study will also have large beneficial to real field in the future. Keywords: Bisphenol A, Titanium dioxide, Nitrogen lanthanum co-doped catalyst, Sunlight degradation, Real field application