Preparation Of Fe₂O₃ Nanoparticles Doped With Indium And Photocatalytic Degradation Property Of Rhodamine B

It is difficult to deal with the industrial wastewater containing printing and dye due to its high content of organics,complicated composition,deep chrominance and variable water quality.With the fast development of dye industry,thousands of dye is used at present.Therefore,it has been a focus topic for the environmental protection department to develop the effective treatment technology on printing and dyeing wastewater.In recent years,photocatalytic degradation technology has attracted more and more interest in the fields of wastewater containing printing and dye treatment using solar energy as energy source.The organic compounds can be degraded into smaller molecules and further oxidized into water and carbon dioxide.As a knid of photocatalyst,Fe₂O₃ particles with narrow orbidden band width show good photoelectrochemical response under the sunlight.However,the chemistry nature of Fe₂O₃ particles is not enough stable.In this dissertation,Fe₂O₃ nanoparticles with different morphologies and doped indium content have been synthetized and their photocatalytic degradation property of rhodamine B has also been studied.First,Fe₂O₃ nanoparticles doped with different indium content have been prepared by changing the proportion of reactants and kinds of additive in the hydrothermal reaction system.The granulars,flake,needle-like,and cubic-shaped morphologies of Fe₂O₃ doped with indium were obtained.All the target products obtained in this study were characterized by X-ray powder diffraction?XRD?,and Fourier transform infrared?FTIR?spectroscopy,scanning electron microscopy?SEM?,differential scanning calorimentr?DSC?,and thermgravimetric analyzer?TGA?.The results showed that Fe₂O₃ nanoparticles doped with less than 10 wt%indium exhibited pure ?-Fe₂O₃ crystal phase,and had a high degree of crystallinity and good dispersion.In addition,the diatomite loaded Fe₂O₃ nanoparticles was obtained by hydrothermal methods using diatomite as substrate and the morphology was characterized by FTIR,SEM,DSC,and TGA.The results showed that Fe₂O₃ nanoparticles were loaded onto the surface of diatomite.Second,the effect of Fe₂O₃ nanoparticles doped with indium on photocatalytic degradation property of rhodamine B was dicussed under uv irradiation and visible light irradiation in the present of hydrogen peroxide.The granulous Fe₂O₃ nanoparticles doped with 10wt%indium showed the highest degradation efficiency when 10-20 mg of catalyst and 30-50 ?L of H₂O₂ were used in the reaction system at pH=4.Finally,the degradation mechanism of rhodamine B was investigated by analysing intermediate products using high performance liquid chromatography?HPLC?and liquid chromatography/mass spectrometry?LC-MS?.The rhodamine B could be completely degraded after 18min by ultravioletlight irradiation.Degradation mechanism was described as follows:hydroxyl-OH first attacked unsaturated conjugation bond of chromophoric group in rhodamine B,which could make it broken,and remove ethyl group and other functional groups such as carboxyl and amidogen.Then,the benzene ring in the rhodamine B was broken into straight-chain organic acid molecule.With hydroxyl OH continuously attack,the organic acid was finally degraded into H₂O and CO₂.