Degradation Of Methylene Blue By Hematite In Heterogeneous Fenton-like Reaction

Dye wastewater is a typical refractory organic industrial waste water which has highcolor, high organic content, complex and volatile components,as well as poor biodegradability.It has great harm to the environment. Seeking a cost-effective method to treat dye wastewaterhas been a problem of the water pollution treatment.Heterogeneous Fenton reaction system indealing with high chroma and nonbiodegradable printing and dyeing wastewater can solve theproblem that the heterogeneous Fenton catalyst has a narrow range of pH for reaction, thedifficult separation and reaction media easy to drain causing secondary pollution, and thereaction process generates iron sludge resulting in the increase of processing cost. So theheterogeneous Fenton catalyst has a good application prospects.In this papers, methylene blue solution is used to be the simulate contaminants, thecatalytic activity of natural hematite as heterogeneous catalysts for Fenton reaction. Whetherthe light under the two conditions, the influence of the amount of catalyst, H₂O₂dosage,initial pH value of different factors were investigated in the hematite catalytic heterogeneousFenton reaction, and the effects of the treatment for simulated wastewater using Fentonreagent was compared. Degradation of methylene blue dye waste water using pretreatednatural hematite single factor and orthogonal experiments without light conditions. TheExperimental results show that the optimal reaction conditions is the catalyst dosage of3g/L,H₂O₂dosage of3ml/L, reaction time of240min, the initial reaction pH of9. Methylene bluedye decolorization rate can reach95.74%. Under UV irradiation conditions, optimum reactionconditions is the catalyst dosage of3g/L, H₂O₂dosage of2ml/L, the reaction time of240min,the reaction of the initial pH for5, decolorization rate of methylene blue dye reached97.85%.The degradation of methylene blue simulated wastewater using Fenton reagent to obtain theoptimal reaction conditions by orthogonal experiments, the temperature of80°C, the catalystof Fe2+dosage of10ml/L, H₂O₂dosage of25ml/L, reaction time of60min. Under optimumconditions, the heterogeneous Fenton and heterogeneous Photo-Fenton system processing wastewater methylene blue effect is significantly better than the Fenton reagent.The design of H₂O₂+UV, hematite+H₂O₂non-homogeneous Fenton, hematite+H₂O₂+UVheterogeneous Photo-Fenton, as well as H₂O₂four reaction system as a controlled experimentto prove that the heterogeneous Fenton wastewater the advantages of color removal. Thecatalyst can be repeatedly reused and reused five times after the removal of methylene blue.The removal of methylene blue can still be maintained above80%, indicating that thiscatalyst is a good prospect of application.