Study On Degradation Of Organic Matter By Membrane-supported Heterogeneous Fenton Catalyst

In the rapid developing industrial era,an increasing number of refractory organic substances in wastewater causes certain damages to the environment.Especially,an antibiotic wastewater,as a new type of pollutant,obtains characteristics of containing highly toxic,being relatively stable and difficult to degrade.Conventional methods for degrading antibiotics,such as physical,chemical,and biological methods,have been unable to meet the degradation requirements of antibiotics.Advanced Oxidation Process has been applied to meet the requirement of dealing with the antibiotic wastewater.Fenton reaction provides·OH,its strong oxidation ability conducts an effective degradation effect on antibiotics.Ciprofloxacin?CIP?was used as the target pollutant in this study.Nafion membrane was used as the photo-assisted heterogeneous Fenton catalyst for the reaction to explore the degradation effect of ciprofloxacin.This study analyzed the kinetics and mechanism of the degradation reaction of ciprofloxacin.This research explored the pretreatment of Nafion membrane,the method of loading iron and the optimal loading conditions.It investigated the effect of Nafion/Fe³⁺membrane under ultraviolet-assisted heterogeneous Fenton system to degrade ciprofloxacin and the effects of H₂O₂ concentration,pH,temperature,and initial concentration of ciprofloxacin on the degradation of ciprofloxacin.It also discussed the Nafion/Fe³⁺membrane conducted a vital catalytic degradation of ciprofloxacin during recycling and iron dissolution.The results presented that with an optimal loading of 26.5mg/g,the Nafion/Fe³⁺membrane played a degradation rate of 88%within 2 hours,and ciprofloxacin can be completely degraded within 4hours.A further exploration of the influence of different influencing factors on the degradation also have been observed.Through a single factor experiment,ciprofloxacin degraded at 20?,pH=3,H₂O₂=100mg/L,and the concentration of ciprofloxacin was 50mg/L best effect.In the process of cyclic degradation of ciprofloxacin,the degradation of ciprofloxacin was better in two cycles.Combined with the results of XRD and XPS,it can be detected that the decrease of multiple degradation efficiency may be due to the decrease of Fe content on the membrane due to the dissolution of Fe³⁺or the heterogeneous reaction of Fe³⁺conversion to Fe₃O₄ on the membrane leading to poor degradation effect.This experiment discussed Nafion/Fe³⁺membrane breakdown test and analyzed by SEM,XRD,XPS and FTIR.One breakdown test on Nafion/Fe³⁺membrane could not observe obvious damage effect on the membrane.In the process of membrane breakdown test,Fe³⁺has a valence change during the reaction and iron ions dissolve.After five times breakdown tests,the C content on the membrane decreased.Although Nafion/Fe³⁺membrane is degraded,the main skeleton and functional groups can still be maintained.After reloading,the Nafion/Fe³⁺membrane still had catalytic activity,which can maintain twice efficient degradation of ciprofloxacin.The kinetic analysis of the degradation of ciprofloxacin by the membrane-loaded heterogeneous Fenton system showed that the degradation reaction process of ciprofloxacin fits first-order kinetic relationship.The greater the initial concentration of the ciprofloxacin solution,the lower the degradation rate of the solution.