| The traditional Fenton method makes use of Fe2+ to catalyze the process of H2O2 generating ·OH which can degrade pollutants,this treatment can achieve the purpose of purifying water and it owns the advantages of satisfied treatment effect,fast reaction process and simple need of method and facilities.However,the treatment effect of the Fenton method is limited by the pH of the reaction solution,and the Fenton reaction produces a large amount of iron sludge,which is expensive to dispose as solid waste.Therefore,there is an urgent need to develop new Fenton catalysts that are efficient,recyclable and low pollutant in the field of wastewater treatment.In this work,by comparing the traditional Fenton and molybdenum sulfide-assisted catalytic Fenton reactions,two new Fe3O4-based heterogeneous Fenton catalysts were developed and optimized on the basis of clarifying their co-catalytic mechanisms.The synthesized catalyst has good Fenton catalytic properties,recyclability and good application prospects.In this paper,the physical configuration of the catalyst and the degradation mechanism of pollutants are studied,and the path of catalytic degradation of pollutants by heterogeneous Fenton catalysts are clarified.The main research methods and conclusions of this work are as follows:The effect of MoS2 as a co-catalyst on pollutant degradation was investigated under homogeneous Fenton conditions.The results show that the addition of MoS2 to the homogeneous Fenton reaction can effectively increase the conversion rate of Fe3+ to Fe2+.Under experimental conditions which exists the half Fe2+ and H2O2 of homogeneous condition,with the addition of MoS2 the reaction can still degrade an equal amount of contaminant RhB,and it can also increase the adjustment towards pH.The study of the degradation process mechanism proves that after the addition of MoS2.the Fe2+ concentration in the solution can be effectively increased,and the Fe3+/Fe2+conversion rate is about 1 time that of the original.The free radical quenching experiment finds that the contribution of various free radicals are as follows:·O2->·OH>1O;Finally,the study also combined with LCMS to propose a possible degradation pathway for RhB.Heterogeneous catalysts MoS2-Fe3O4 composites were synthesized to degrade RhB.Fe3O4 was synthesized by chemical precipitation,and finally MoS2 was loaded on Fe3O4 by hydrothermal method to obtain the composite material.After optimizing the synthesis method of the catalyst,the material synthesized in a 6:5 ratio has the best catalytic activity,and 98%RhB removal can be achieved in 25 minutes.The materials analysis results show that the catalyst has a large number of pore structures,MoS2 and Fe3O4 are tightly bound,and the doping of Mo improves the leaching rate of Fe2+ and the conversion rate of Fe3+/Fe2+.Experimental results show that the degradation of RhB is a first order reaction,and the contribution of various free radicals are as follows:·O2->·OH>1O;Five cycle experiments show that the catalyst has good stability and reusability.CuS-FeS-Fe3O4 ternary composite catalyst was synthesized by chemical precipitation,and the activity and principle of Fenton catalytic degradation of RhB is studied.The effect of the synthesis method is optimized by using the control variable method.The orthogonal analysis showed that the CuS content has a significant effect on the catalyst’s performance,and on the basis of the orthogonal analysis,the catalyst had the best catalytic performance at a stoichiometry ratio of 1:4:20,and the catalyst achieved a 97%RhB degradation rate at 120 min.The degradation curve analysis shows that the degradation of RhB by the catalyst is a first order reaction,and the 5 cycle experiments show that the catalyst has good reusability and stable catalytic performance.Materials analysis experiments showed that the catalyst has a rich microporous structure,XRD,XPS shows that FeS,CuS and Fe3O4 are combined,and the electronic effect between the metal elements greatly increases the Fenton catalytic capacity of the composite. |
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