Study On Enhanced Oxidation Of Contamitants By Ferrate(Ⅵ)and Manganese(Ⅶ)in The Presence Of Epigallocatechin Gallate

With the industrial production and human activities,more and more artificial micro organic pollutants enter into the ecological environment and human living environment.The content of these pollutants is relatively low,but it can not be decomposed by natural decomposition,and it contains bioaccumulability,and enters human or animal body through food chain,which caus es great harm.This paper mainly studies the use of two typical and common oxidants potassium permanganate and potassium ferrate to remove a variety of typical trace organic pollutants,compares their effects in treating different kinds of organic pollutan ts and the efficiency of two oxides in treating the same kind of oxides in different environments and infers the degradation path of an organic pollutant in the oxidation process.Meanwhile,we use a natural green tea extract,epigallocatechin gallate to strengthen the oxidation ability of potassium permanganate,we also analyze the effect of oxidative degradation of an organic pollutant in different environments.At the end of the research,we conjecture the reaction mechanism of the system.As common oxidants,potassium permanganate and potassium ferrate are often used in water pre oxidation process in water treatment process.Electron transfer is realized by the valence change of high valence Fe（Ⅵ）Mn（ⅥI）in the reaction process,and the intermediate valence products also have strong oxidation properties.Comparing the degradation performance of the two oxides on six different organic pollutants,it is found that potassium permanganate is easy to attack electron rich groups（such as carbon carbon double bond）,and it is stable;potassium ferrate has strong ability to attack electron rich groups,but it has irreversible decomposition process,and its oxidation removal performance is not stable.In acidic environment,potassium ferrate showed better removal efficiency for carbamazepine and bisphenol A,under the established reaction conditions,the removal rates of the two pollutants were 76%and 63.7%respectively.While the degradation efficiency of potassium permanganate in different p H environment depe nded on the nature of the pollutants.In high alkalinity environment and natural organic matter environment,the oxidation performance of the two oxidants are affected to some extent,and the natural organic matter has little effect on the oxidation perfor mance of potassium permanganate,the reduction of removal rate is less than 5%.When there are reducing substances in the water environment,the oxidation properties of the two oxidants are improved correspondingly.In the iron reaction system,sulfite ions are added,and sulfite ions are oxidized by strong oxidants to form active radicals of trace sulfur elements.In the manganese reaction system,the reduced high valence manganese（ⅥI）will form manganese intermediates with stronger oxidation properties.n the natural water environment,the impurities in the water environment will affect the oxidation efficiency.Adding more oxidants can improve the oxidation performance of the two reaction systems.During the oxidation of bisphenol A in iron manganese ox ides,ring opening,hydroxyl substitution and carbon carbon bond breaking reactions occur.EGCG is a kind of natural and healthy green tea extract.Its reducibility and complexation with metal ions are the important basis for us to strengthen the oxidation performance of potassium permanganate.Through reduction,high valence manganese（ⅥI）is reduced to manganese（V）and manganese（Ⅲ）with stronger oxidation performance,and the two unstable intermediates are fixed by their good ability of binding metal ions,so as to be used for efficient removal of pollutants.Under the given experimental conditions and the action of EGCG/KMn O₄ system,the oxidation degradation rate of bisphenol A was 96.8%at high p H,which is related to p Ka value of BPA itself.The dissolved oxygen in water has a negative effect on the system,and the oxidation process is independent of singlet oxygen.The coexisting substances（HCO₃^-,NOM,etc.）in water environment have influence on the oxidation process,NOM has little influence,and the consistency of bicarbonate is negatively correlated with the degradation rate of BPA.Then,the process of bisphenol a removal by EGCG/potassium permanganate system in natural water environment is discussed.We collected natural water samples from different links in the water treatment process.When the natural water is further treated,the degradation rate of bisphenol A by the system is correspondingly improved.Finally,we confirmed the existence of manganese（Ⅲ）and manganese（V）by pyrophosphate quenching experiment and full band scanning of UV spectrophotometer,and inferred the reaction mechanism of the system through the change of absorption peak area corresponding to different substances in the reaction process.The main action of the reaction system is manganese（Ⅲ）and manganese（V）.After the EGCG’s complex action,the two unstable oxides are stable.