Preparation Of Bimetal Fe/Mn-GAC Catalyst And Degradation Of Aniline Aerofloat By Fenton With Fe/Mn-GAC Catalyst

In recent years,with the development of mining industry in China,the wastewater discharged from mineral processing has posed a great threat to ecological environment and biosafety.Aniline aerofloat is often used as the collecting agent in floatation process for Metal-sulfide ore,which leaves plenty of residuals in floatation wastewater.As the phosphorus and aniline group in its molecular structure,it shows biotoxicity and resistant to degradation and it is difficult to get effective removal by conventional methods,thus increasing the difficulty of treatment of mineral processing wastewater.The thesis has studied the catalytic Fenton degradation of aniline aerofloat by Fe-Mn bimetals supported catalyst,which was prepared using granular activated carbon as the carriers.The process parameters of catalyst preparation and the factors which have influences on aniline aerofloat degradation were investigated.The mechanism of catalytic degradation was explored,providing theoretical and technical guidance for the treatment of mineral processing wastewater and the degradation of aniline aerofloat.The Fe-Mn heterogeneous Fenton catalyst was prepared using cyclic pyrolysis method,preparation parameters of the catalyst were optimized by response surface method and the characterization analysis of optimized catalyst was performed.In the process of catalyst preparation,the order of influence of parameter is preparation temperature>Fe-Mn ratio>>the total ion concentration.The combination optimized by response surface model as follows:the Fe-Mn ratio is 9.50,the preparation temperature of 362.07℃,the total ions concentration is 1.09 mol/L,under this condition,the regression model predicted that the removal efficiency of aniline aerofloat is 96.56%,the deviation between the actual value verified by parallel experiment and the predicted value of model is only 0.60%.The prepared Fe/Mn-GAC catalyst was characterized by SEM,XRD,BET,FT-IR,XPS,which showed that the catalyst is a mesoporous material with an average pore size of 2.91 nm and special surface area of 100.5m²/g,the surface of Fe/Mn-GAC loaded Fe-Mn bimetallic oxide Fe3-x Mnx O4,and abundant-OH groups was detected which provides a benefit to catalyst activity.The Fe/Mn-GAC catalytic Fenton system was established for the degradation of aniline aerofloat.Fe/Mn-GAC shown better catalytic degradation than Fe²⁺,Mn²⁺,GAC,nano-Fe3O4,Fe-GAC,Mn-GAC,Fe/Mn-GAC-1 Fenton-like catalyst.Single factor tests on p H value,catalyst dosage and H2O2 concentration on aniline aerofloat degradation efficiency were studied:p H value was 3.0,catalyst dosage was 10.0 g/L,H2O2 concentration was 17.15 mmol/L,after120 min processing,the TOC removal efficiency of the 200 mg/L aniline aerofloat simulated wastewater reached to 84.77%,and the catalyst still has high catalytic activity after used for 5times and recycledThe mechanism of Fe/Mn-GAC catalytic Fenton degradation of aniline aerofloat was investigated based on H2O2 catalytic decomposition and reaction kinetics of pollutants.Catalysts loaded with different metals have varying catalytic decomposition capacities for H2O2.XPS analysis of bimetal Fe/Mn-GAC catalysts before and after the reaction,the results shows that the effective decomposition of H2O2 is related to Fe（II）,Fe（III）,Mn（III）and Mn（IV）in Fe3-x Mnx O4.The addition of radical inhibitor tert-butanol（TBA）andρ-benzoquinone（ρ-BQ）significantly inhibited aniline aerofloat degradation,indicated that·OH and·OOH/·O2^-were equally important in the Fe/Mn-GAC heterogeneous Fenton system.The residual H2O2 and the generation of·OH were determined,the results revealed that the formation of·OH in the later stage reaction was independent of H2O2 in the solution,combining the degradation kinetics of aniline aerofloat manifest that·OH,·OOH/·O2^-dominated in different stages of the reaction,respectively.