Synthesis Of Fe₂O₃/Fe₃O₄@Biobr Mnps And Performance Study Of The Degradation Of Organic Pollutants

Currently, the continuous increase of trace organic pollutants in water environment has very adverse impact on aquatic ecosystems and human health, particularly the antibiotic and dye type of organic pollutants has become a hot focus in recent years. Semiconductor photocatalysis can use abundant solar energy to degradation of organic pollutants, which has an important significance to the global new energy development and environmental governance. However, like traditional heterogeneous photocatalytic titanium dioxide materials with wide band gap, make its low utilization rate on the sunlight. Moreover, the electrons and holes is easy to compound and the quantum yield is low. In order to make the photocatalytic technology further to practical application, the development of new high efficiency of the visible light catalytic material system is inevitable trend. In recent years, the study found that compounds Bi system have excellent visible light catalytic activity and it is practical and efficient for the development of semiconductor photocatalysis provides an important basis.This paper mainly studies the synthesis of magnetic nano materials Fe2O3@BiOBr and Fe3O4@BiOBr as well as their characterization of physical and chemical parameters. Research on organic dyes and antibiotics pollutant removal mechanisms under visible light irradiation, the degradation pathways and toxic degradation products, also studied the degradation in the realization of the role of the magnetic field in the solution of nano materials separation and reuse. The details are as follows:(1) By hydrothermal/co-precipitation method for the synthesis of magnetic nano Fe2O3@BiOBr and Fe3O4@BiOBr catalyst; characterized by scanning/transmission electron microscopy, X-ray derivative/photoelectron spectroscopy, magnetic/UV-vis other parameters can know the composite material has a good morphology, the smaller band gap, easy separation and recovery features.(2) Through the dye Rhodamine B (RhB), methyl orange (MO) degradation effect studies may know BiOBr@Fe2O3magnetic nanoparticles with BiOBr@Fe3O4catalyst for RhB and MO have a better degradation effect,60min time basic can degrade completely. In comparison, the effect BiOBr@Fe3O4are superior to BiOBr@Fe2O3. To this end, selected the better catalytic activity, more efficient magnetic nano Fe3O4@BiOBr catalyst as the object for further study.(3) Choosed Norfloxacin (NFLX) as the target pollutants to investigated four active groups·O2-、1O2、·OH、h+affect on the overall degradation process, the experimental results show that four of the free radical degradation process the contribution of·O2-<1O2<·OH<h+, and the hydroxyl radical is mainly due to the role of the hole with water molecules to produce; Meanwhile, effects of different concentrations of Fe3+, HCO3", dissolved organic matter (DOM) and the effects of different pH conditions on the degradation process, the results show, Fe3+, HCO3-degradation process no significant effect on the norfloxacin, and dissolved organic matter on the adsorption of norfloxacin stronger than photolysis; with the pH is increased, NFLX degradation rate has increased efficiency and, under alkaline pH conditions present in the solution of higher concentration of hydroxide ions (OH-) with the "hole" binding a large amount of·OH to accelerate the degradation process.(4) Antibacterial test results show that as the reaction proceeds, the relative luminance of a test strain is gradually increased, i.e., the toxicity of the product was gradually reduced; recycled catalyst results show that both the four catalysts round robin experiment can be maintained at more than80%degradation rate and the magnetic nano-catalyst BiOBr@recovery effect than BiOBr@Fe2O3.