| In recent years,advanced oxidation technology has developed rapidly.As the one of advanced oxidation technology,Fenton oxidation has been reported in many literatures.The Fenton reaction has many advantages,such as fast reaction speed,high oxidation efficiency,simple operation and mild reaction conditions.And it is particularly suitable for the treatment of organic materials that are difficult to biodegrade.However,as people deepen their understanding of the method,some deficiencies in the traditional Fenton degradation of pollutants were found.For example,the reaction must be carried out under strong acidic conditions,Fe2+ is difficult to recycle and reuse,the utilization of H2O2 is low,the increasing of the system pH may produce a lot of sludge and may cause secondary pollution.Therefore,the heterogeneous Fenton reaction system attracts the attention of researchers.Compared with the traditional homogeneous Fenton reaction,the heterogeneous catalyst has a wider scope of application.In addition,this method also has the characteristics of less free iron ion generation,simpler catalyst separation,and easy to recycle.In view of the problems existing in the traditional homogeneous Fenton reaction system,this paper studied and prepared the ferric chloride oxide(FeOCl)and FeOCI/SiO2 composite catalysts.The influence of factors such as catalyst dosage,initial pollutant concentration,initial pH value,and H2O2 addition amount on the decolorization efficiency of pollutants was investigated.The main research content of the paper includes:(1)Preparation and Properties of FeOCl CatalystsFerric chloride and iron oxide were used as raw materials,and FeOCl catalysts were prepared through chemical and vapor phase transfer conditions under sealed and unsealed conditions,respectively.Then using hydroxyl free radicals produced by heterogeneous Fenton reactions to degrade contaminants in water.The catalysts were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The results showed that the catalysts exhibited a lamellar structure,better crystal shape and higher crystallinity.Catalytic degradation experiments showed that the catalytic effect of the prepared catalyst under sealing conditions(M-Fe)was much higher than that of the catalyst obtained under non-sealing conditions(W-Fe).In addition,the effects of the initial concentration of rhodamine B(RhB),H2O2 addition amount,catalyst dosage and initial pH value on the decolorization rate of RhB were studied.Under the condition of initial RhB concentration 100 mg/L,M-Fe catalyst dosage 0.5 g/L,H2O2 concentration 20 mmol/L,initial pH 4.5,after 15 min of catalytic degradation,the decolorization rate of RhB has reached above 99%;And at the initial pH 7.0,after 40 min of visible light catalytic reaction,the decolorization rate of RhB can reach 95.5%.The results show that the catalyst has good stability,and the decolorization rate of RhB has no obvious decrease after 3 cycles.(2)Modification of FeOCl and the application in degradation of RhBFurther,a FeOCI/SiO2 composite catalyst was prepared by melt infiltration method.The catalysts were characterized by XRD,FT-IR and DRS.At the same time,the photocatarlytic property was also studied.The effects of the initial concentration of RhB,the amount of H2O2 added,catalyst dosage and the initial pH on the decolorization rate of RhB by the composite catalyst were investigated.The results showed that:when the molar ratio of iron and silica is 0.24:1 in the composite catalyst,under the condition of initial RhB concentration 100 mg/L,catalyst dosage 0.5 g/L,H2O2 concentration 20 mmol/L,initial pH 4.5,the decolorization rate of RhB has reached 98.1%after 10 min of catalytic degradation.The performance of the catalyst was stable,and the decolorization rate of RhB has no obvious decrease after 3 cycles. |
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