Synthesis of Bismuth-based Nanomaterials for the Photodegradation of Organic Dyes

【摘要】：With rapid development of modern industry,environmental pollution and water contamination have become a serious problem.Especially waste water has seriously affected human health.Meanwhile,the rapid industrialization has also led to the large use of water for drinking,transportation,household needs,aquatic life,recreation even fishing.Chemical industries,such as textile industry,dye industry,the pharmaceutical industry and leather industries need use a lot carcinogenic pigments and dyes,which has badly destroyed human life and aquatic life of sea animals.At present,more and more efforts have been devoted to the way of treating waste water.Many physical methods have been used to treat waste water such as adsorption,and coagulation etc.Although these techniques can separate dyes from water but these processes cannot degrade the dyes from waste water.Recently there have been more reports on the use of the semiconductor photocatalyst for the degradation of the azo dyes.Semiconductor photocatalysis has been regarded as a green technology for waste water treatment and environmental remediation.Photocatalysis can be regarded as an effective way to deal with the residual dyes pollutants from waste water.This dissertation is mainly focused on the bismuth oxide and their composites with other semiconductors.The research is mainly targeted for the photocatalysis,degradation of organic dyes and some antibiotics.We begin with the preparation of the bare bismuth oxide for the degradation of organic dyes in visible light irradiation and it was examined by different characterizations such as X-ray diffractometer,x-ray photoelectron spectroscopy(XPS),scanning electron microscope(SEM),transmission electron microscope(TEM),Fourier transform infrared(FT-IR)analysis,Raman analysis,EDS,and Photoluminescence spectra.The energy band structure was studied by the ultraviolet-visible diffuse reflectance spectroscopy(UV-vis DRS).To improve the photocatalytic activity of bismuth oxide,organic and inorganic semiconductors are used to make nanocomposites with the bismuth oxide.Such as the composite of ZnO/Bi2O3,ZnO/Bi2O3/C3N4,Bi2O3/C3N4 and so on.The results demonstrate that the addition of other semiconductors with the bismuth oxide not only increased the efficiency bare Bi2O3 but also the Photostability of the material was greatly improved.Meanwhile in this dissertation the photocatalytic degradation test was carried on different dyes,such as methyl orange,Rhodamine B,phenol and O-toluidine.The research system can supply a promising photocatalytic degradation materials for waste water treatment containing pigments and dyes.