Studies On Oxydative Degradation Of Methylene Blue By Copper Ferrite Base Photo-Fenton System

With the rapid development of printing and dyeing industry,wastewater treatment increasingly becomes difficult due to the large emission of printing and dyeing wastewater and the strict pollution control standards.In order to solve this problem,more and more scientific researchers strive to research the purification and recycle of printing and dyeing wastewater.The photo-Fenton technology has been attracted much attention because of efficient pollution control capabilities,wide applicability and simple operation.In this dissertation,Fenton technology with high efficiency pollution control capabilities was introduced,depending on elaborating the source of printing and dyeing wastewater,characteristics of water quality and existing problems in wastewater treatment.Herein,we attempt to improve the reaction efficiency of oxidation degradation methylene blue using the copper ferrite based photo-Fenton system by different ways and to analyze the possible reaction mechanism.The specific conclusions are as following:?1?Using CuFe₂O₄ prepared by sol-gel method as catalysts,in the process of catalysis oxidation of methylene blue by photo-Fenton reaction,the degradation rate of target molecules increased from 52.0%to 92.1%within 80 min by introducing tartaric acid.The delivery rate of the superoxide radicals and hydroxyl radicals produced in the TA-H₂O₂-CuFe₂O₄-photo system to the oxidation degradation of methylene blue were about 10%and 88%,respectively.In addition,the addition of tartaric acid not only increases the formation rate of hydroxyl radicals in the system,but also inhibits the leaching of metal ions on the surface of the heterogeneous catalyst and the deposition of dissolved metal ions.Electron transfer effect between ligand and metal ion was known as the main mechanism for the system.?2?By optimizing the influence factors of the crystal structure and of morphology of the obtained samples,we found the self-assembled hollow copper ferrite nanospheres were successfully prepared when crystallization temperature was 180^oC,the amount of PVP was 0.25 g,the amount of NaAc was 9 mmol and crystallization time was 24 h.Compared with the copper-ferrite nanoparticles prepared by the sol-gel method,the self-assembled copper ferrite hollow nanospheres not only have higher specific surface area and good magnetic properties,but also show excellent catalytic performance and good reusability in catalysis Fenton reaction oxidation degradation of methylene blue.Moreover,the key to improving the catalytic activity was good photoelectron productivity,low transmission impedance and large specific surface area.?3?The graphite carbon-coated copper ferrite hollow nanospheres?H-CFO@C-600°C-0.15 SPs?were successfully prepared by graphitizing the self-assembled copper-ferrite hollow nanospheres coated with carbon layer?H-CFO@C SPs?.Compared with copper-ferrite hollow nanospheres?H-CFO SPs?,H-CFO@C-600°C-0.15 SPs not only have better magnetism and optical response,but also could increase the degradation rate of methylene blue to 97.0%in the photo-Fenton reaction.Furthermore,good catalytic properties of H-CFO@C-600°C-0.15 SPs were attributed to the synergistic effect between the photocatalytic mechanism and the photo-Fenton mechanism.