Degradation Of Chlordane In Cyclodextrin By Goethite And Schwertmannite Catalyze Photo-fenton

This article took chlordane as the target pollutant andβ-cyclodextrin as the soil elution solvent to explore the optimal reaction conditions for the degradation of chlordane in the cyclodextrin solution by the goethite and schwertmannite catalyze Photo-Fenton reaction.And the degradation mechanism and so on.The main research contents are:（1）The adsorption effect of goethite and schwertmannite on cyclodextrin and the influence of cyclodextrin concentration on mineral adsorption of chlordane;（2）Chemical preparation and characterization of goethite and schwertmannite;（3）Exploring the optimal reaction conditions for the degradation of chlordane by goethite and schwertmannite catalyze Photo-Fenton reaction:including initial p H,The dosage of goethite/schwertmannite,H₂O₂ concentration,cyclodextrin concentration;（4）Explore the mechanism of geothite and schwertmannite catalyze Photo-Fenton reaction and possible degradation pathways.The results are as follows:1.The adsorption trend of goethite and schwertmannite to cyclodextrin and chlordane was the same.First with the increase of cyclodextrin concentration,the adsorption capacity of mineral to cyclodextrin increased and then leveled off.When the concentration of cyclodextrin was 0.8 g/L,the adsorption capacities of goethite and schermanite were 84.8 mg/g and 12.98mg/g,the adsorption capacities of goethite and schertzmanite on chlordane were 6.98 mg/g and 3.83 mg/g.2.The chemically prepared goethite and schwertmannite were characterized.XRD analysis showed that the prepared goethite and schwertmannite were pure minerals;through scanning electron microscopy,it could be observed that the goethite was needle-like minerals,the particle size range is 0.5-2.5μm;Most of the schwertmannite are small spheres,the particle size range is 1.5-4μm and both minerals have obvious agglomeration;respectively,the BET specific surface area analysis shows that the specific surface areas of the obtained goethite and schwertmannite are 33.11 m²/g and9.71 m²/g.3.The optimal reaction conditions for degrading chlordane by the goethite and schwertmannite catalyzed Photo-Fenton:goethite system,goethite dosage was 10 mg/L,cyclodextrin concentration 0.8 g/L,initial solution p H=3,H₂O₂ concentration was 50 mmol/L;schwertmannite system,schwertmannite dosage was 60 mg/L,cyclodextrin concentration was 0.8 g/L,solution initial p H=3,H₂O₂ concentration was 50 mmol/L.4.In the process of degradation of chlordane by goethite and schwertmannite catalyze Photo-Fenton reaction,the surface catalytic reaction mechanism of the mineral and the UV photocatalytic reaction work together to promote the decomposition of H₂O₂ to produce·OH,which directly attacks the pollutants and then affects the degradation effect of chlordane.During the degradation of chlordane,the oxidation reaction of chlordane occurs,and several·OH attacks a chlordane molecule to form a new ring-opening product after dechlorination.Such as:Oxide chlordane,hydroxyl hexachloro,methyl eugenol,2-methoxy-6methyl,1,2,4,5-tetrachlorobenzene and other substances.Through the degradation of chlordane by goethite and schwertmannite catalyze Photo-Fenton reaction,the optimal conditions of the Photo-Fenton reaction of goethite and schwertmannite to degrade chlordane were explored,and the mechanism of the Photo-Fenton reaction of goethite and schwertmannite to degrade chlordane was speculated,providing technical support for the remediation of Ocps contaminated soil.