Study On The Photocatalytic System Construction And Oxidation Performance Of Manganese Slag And Vanadium Titanomagnetite

Advanced oxidation technology is an efficient technology for water environment treatment.Heterogeneous catalyst has strong oxidation ability,mild reaction conditions and easy recovery,so it is widely studied in advanced oxidation technology.The catalytic efficiency and stability of the catalyst is the focus of the research,it can achieve economic and environmental protection at the same time of efficient treatment,which is of great significance to the application of the catalyst and the treatment of organic wastewater.Electrolytic manganese slag and vanadium titanium magnetite both contain active components such as transition metal oxides,which can be used as photocatalysts in organic wastewater treatment theoretically.In order to treat waste from electrolytic manganese slag and utilize vanadium titanomagnetite as resource,the heterogeneous oxidation systems of photo assisted electrolytic manganese slag/H₂O₂ and photo assisted vanadium titanomagnetite/PMS were constructed respectively,and the oxidation degradation performance of bisphenol S was studied.The main conclusions are as follows:(1)There are active metal oxides such as Mn and Fe in electrolytic manganese slag,and the oxide forms are MnO?FeO;The content of vanadium and titanium associated with vanadium titanomagnetite is very low,and the main metal oxide is Fe₃O₄.The valence state of Fe in the vanadium titanomagnetite after catalysis has changed,part of Fe²⁺is transformed into Fe³⁺,and the surface is strongly hydroxylated.(2)The degradation of bisphenol S by photo assisted electrolytic manganese slag/H₂O₂ heterogeneous oxidation system with electrolytic manganese slag as photocatalyst was very effective,the order of degradation ability of each system was electrolytic manganese slag/UV/H₂O₂>UV/H₂O₂>electrolytic manganese slag/H₂O₂>electrolytic manganese slag/UV>UV.The interaction between the influencing factors did not contribute much to the degradation of bisphenol S in the system(p<0.05).The optimum conditions were p H=7,dosage of electrolytic manganese slag 0.57g/L,H₂O₂concentration 10 mmol/L and initial bisphenol s concentration 2?mol/L,under these conditions,bisphenol s could be degraded by more than 90%in 80 min.(3)In the photo assisted electrolytic manganese slag/H₂O₂ heterogeneous oxidation system,·OH is the active component,while the leaching coexisting active metal component is not conducive to the degradation of bisphenol S,mainly due to heterogeneous catalysis.The electrons and holes generated by the active metal oxides under UV irradiation decompose H₂O₂ to generate·OH;In the model of·OH formation rate using isopropanol as probe,R^f_·OH is in the range of 3.22×10^-9?1.1×10^-8mol/(L·s),which is similar to that obtained by using nitrobenzene as probe R^f_·OH(6.5×10^-9mol/(L·s))is basically the same;The DOM impact prediction model based on R^f_·OH has a good consistency,and can be extended to other organic pollutants.(4)The order of degradation ability of each system to bisphenol S is:vanadium titanomagnetite/UV/PMS>vanadium titanomagnetite/PMS>UV/PMS>vanadium titanomagnetite/UV;within 50 min,the degradation rate of PMS was 100%?mol/L,the degradation efficiency of bisphenol S was 99.2%,while the photo assisted vanadium titanomagnetite/PMS heterogeneous oxidation system could completely degrade 100%in 50 min,The degradation rate of bisphenol S is almost twice as fast as that in dark,which indicates that vanadium titanomagnetite can activate PMS more effectively under light condition.(5)In the photo assisted vanadium titanomagnetite/PMS heterogeneous system,the optimum conditions for the degradation of bisphenol S were as follows:PMS concentration of 4mmol/L,vanadium titanomagnetite dosage of 0.1g/L,p H=7,initial concentration of bisphenol S of 200?mol/L,and the degradation rate was 0.182 min^-1;the degradation rate of bisphenol s was relatively fast under acidic and alkaline conditions,and the active species for oxidative degradation were SO₄·^–and·OH,respectively.(6)The homogeneous reaction also contributed to the degradation of bisphenol S in the photo assisted vanadium titanomagnetite/PMS heterogeneous system,the leaching concentration of Fe was 116 mg/L,and the degradation rate of bisphenol S was 36%in 35 min.Free radical quenching experiments show that the heterogeneous system of photo assisted vanadium titanomagnetite/PMS is mainly surface catalytic oxidation,Fe₃O₄ generates electrons and holes under light conditions,PMS generates electrons to generate SO₄·^–and·OH,and hole oxidizes surface-OH to generate·OH,at the same time,Fe(II)and Fe(III)in vanadium titanomagnetite and dissolved Fe³⁺and Fe²⁺can activate PMS to produce SO₄·^–and·OH.(7)Vanadium titanomagnetite was recovered for four times continuously,and the catalytic effect was still good.In the fifth time,bisphenol S was almost completely degraded within 35 min,with good stability.