The Mechanism Of Microwave Irradiation With Three-dimensional Catalysts Activation Of Persulfate Degrade Quinolones Antibiotics

Fluoroquinolones（FQs）are personal care products containing"4-quinolones"basic structure through artificial synthesis,which belong to the quinolone piperazine group of organisms,and have high chemical and biological stability.Conventional adsorption and biological methods cannot effectively remove pollutants,and the wastewater containing such substances without advanced treatment is likely to cause secondary water pollution or fail to meet the discharge standards.Therefore,it is one of the important water environment problems to be solved to effectively solve the threat caused by drug residue discharge in FQs wastewater.To solve the above problems,three kinds of microwave irradiation-catalyst activated persulfate degradation FQS system was proposed in this study,and the mechanism was studied.In this paper,urea as the dispersant,glucose as carbon source,through hydrothermal preparation of ZnCo₂O₄,C@ZnCo₂O₄,C@ZnFe₂O₄three catalysts.The process conditions of preparing catalysts were optimized from urea dosage,carbon content,calcination temperature,and calcination time.The three kinds of catalysts have good three-dimensional structure by characterization technique.The degradation of LVF,CIP and NOR three quinolone antibiotics was carried out,and only one quinolone antibiotic was selected as the target pollutant in each chapter for mechanism analysis.First,LVF was degraded by the MW-3D ZCO/PS system.Under the experimental conditions of[LVF]=10.0 mg/L,[3D ZCO]=2 g/L,[PS]=0.25 m M,[pH]₀=5,MW=700 W and T=70℃,LVF removal rate reached 92.2%and TOC removal rate was 69.8%after treatment for 40 min,all the reactions conform to the pseudo first-order kinetic model.To reduce microwave energy consumption and reduce the dosage of catalyst,carbon was loaded on to ZnCo₂O₄catalyst.Through network vector characterization technology,it was found that C@ZnCo₂O₄compared with ZnCo₂O₄has good microwave absorption performance.Therefore,the MW-3D C@ZCO/PS system was constructed to degrade CIP.Under the experimental conditions of[CIP]=10.0 mg/L,[3D C@ZCO]=1.5 g/L,[PS]=0.25 m M,[pH]₀=6.5,MW=600 W,T=40℃,after 40min,the removal rate of CIP reached 91.7%,and the removal of TOC was 73.1%.Without microwave irradiation,the degradation rate of CIP is only 49.2%.To facilitate the recovery and utilization of the catalyst,a magnetic C@ZnFe₂O₄catalyst was prepared,and the MW-C@ZFO/PS system was constructed to degrade NOR.Under the experimental conditions of[NOR]=5.00 mg/L,[C@ZFO]=1.5 g/L,[PS]=0.25 m M,[pH]₀=6.7,MW=400 W,T=70℃,after 40 min,the NOR removal rate reached 86.5%,and the TOC removal rate was 69.6%.In addition,considering the existence of many different kinds of ions in the actual water environment,the effects of four inorganic ions(NO₃^–,Cl^–,CO₃^2–and H₂PO₄^–)and organic matter（HA,FA）on the degradation of FQS in these three systems were further investigated.The results showed that the presence of different ions and HA,FA had a certain inhibition effect on the degradation of FQs.Combined with XPS data,the Co（II）-（III）and Fe（III）-Fe（II）cyclic reactions were observed in the three systems.Based on the above analysis,by the free radical quenching experiment and electron spin resonance experiment,it has been proved that SO₄^·-,HO·and·O₂^-exist in the system.The demethylation,dehydroxyl,piperazine,carboxylation,and ring-opening were the main oxidation and degradation pathways were analyzed by HPLC-MS.In addition,the toxicity changes of FQs detected by Vibrio fischeri during the degradation process showed that attention should be paid to the toxicity changes during the degradation process.The results show that the three catalysts have certain stability and reusability.The data of catalyst cycle use can show that the three catalysts have certain stability and reusability.The microwave irradiation-catalyst activated persulfate technology established in the research process can effectively remove quinolone antibiotics.The research results provide a certain theoretical basis and technical support for the application of microwave irradiation in the treatment of wastewater containing antibiotics.