The Synthesis Of Magnetic Mesoporous FeCo₂O₄-Fe₃O₄ Microrods And The Efficiency And Mechanism In PMS Catalyzation For Metronidazole Degradation

Metronidazole?MNZ?,as a nitroimidazole antibiotic,is widely used in the treatment of trichomoniasis amoebiasis,giardiasis,and anaerobic infections.Studies have found that the high solubility and difficult biodegradability of MNZ cause it to accumulate easily in the water environment.MNZ has potential carcinogenic,mutagenic,and toxic properties,MNZ poses a potential risk to ecosystems and human health.In addition,MNZ has potential carcinogenic,mutagenic,and toxic properties,MNZ poses a potential risk to ecosystems and human health.Recently,advanced oxidation technology based on sulfate radials have been acknowledged as alternative and effective technology for toxic and recalcitrant organic contaminants removal.Therefore,this study use magnetic mesoporous FeCo₂O₄-Fe₃O₄ microrod as a heterogeneous catalyst for activating peroxymonosulfate.A series of Characterization methods were applied to analyzed the physical and chemical properties and synthesis path of the catalyst.Then,the the best reaction conditions were explored through batch experiments,and the activation mechanism of free radical of sulfate radical and the reaction mechanism of oxidative degradation of organic pollutants have been further revealed.To sum up,the main experiments and related achievements are as follows:The morphology and composition of the catalyst indicate that the catalyst was successfully prepared.?1?A novel magnetic mesoporous FeCo₂O₄-Fe₃O₄ microrod was synthesized as a heterogeneous catalyst for activating peroxymonosulfate by improving the method of synthesizing FeCo₂O₄.Through SEM,EDS,XRD and other characterizations,we know that the catalyst has been successfully prepared,and FeCo₂O₄-Fe₃O₄ microrods have a rougher surface compared to FeCo₂O₄.BET shows that FeCo₂O₄-Fe₃O₄microrods have a larger specific surface area,pore volume than FeCo₂O₄,the high porosity and surface area of FeCo₂O₄-Fe₃O₄ could possess more active sites to improve its catalytic activity.The analysis of the hysteresis curve shows that FeCo₂O₄-Fe₃O₄ is magnetic and can be easily separated by an external magnetic field.?2?FeCo₂O₄-Fe₃O₄ has excellent catalytic efficiency on PMS than other catalysts.The experimental analysis of MNZ degradation by activated PMS determined that the best reaction conditions for the composite catalyst were 4 mmol L^-11 PMS,0.4 g L^-11 FeCo₂O₄-Fe₃O₄,100mg L^-11 MNZ,the degradation effect of MNZ can reach 96.8%within 60min.When the dosage of PMS is 20 mM,the TOC removal rate of the system reaches 97.4%.In addition,the FeCo₂O₄-Fe₃O₄/PMS system has a wide range of applications.Under the same reaction conditions,the removal efficiency of ciprofloxacin,2,4-dichlorophenol,ofloxacin,and tetracycline can reach78.8%,77.1%,81.3%,and 60.7%,respectively.After five cycles of magnetic recovery,FeCo₂O₄-Fe₃O₄ can achieve a degradation effect reach 68.9%.The catalyst structure is stable,and the ion leaching was lower than the surface water standard.Therefore,FeCo₂O₄-Fe₃O₄ has a broad application prospect as a new type of PMS catalyst.?3?Through the radical quenching experiments and electron paramagnetic resonance?EPR?analysis showd that both hydroxyl radicals?^·OH?and sulfate radicals(SO₄^·-)existed in the reaction and hydroxyl radical?^·OH?is the dominant free radical of the reaction.Through the analysis of XPS,a possible catalytic degradation mechanism was proposed,and the Fe–Co interaction during the reaction was considered to promote the reaction.