Preparation Of Fe₂O₃/CaFe₂O₄ Particles And Photocatalytic Degradation Properties Of Methyl Orange And Phenol

With the development of society,environmental issues have attracted more and more attentions,especially water pollution.Under energy shortage environment,photocatalytic technology as a green,environment friendly,low-power advanced oxidation technology has had a broad application.Nano-TiO2 and Fe2O3 photocatalyst has made good progress in the field of organic degradation of water.However,the degradation efficiency can not meet needs.In recent years,much research on traditional catalyst modification was reported.In this paper,the conventional n-Fe2O3 modified with p-CaFe2O4 composite photocatalyst with p-n heterojunction was obtained and it could improve the photocatalytic properties.In addition,the effect of composite photocatalyst on degradation properties of methyl orange(MO)and phenol was discussed.n-Fe2O3/p-CaFe2O4 composite photocatalyst was prepared using two-step process.First,Fe2O3 particles were obtained by hydrothermal method and using sodium dodecyl sulfate as additive.Second,CaFe2O4 particle were formed on the surface of Fe2O3 particles with the co-precipitation method.Finally,the composite catalyst was obtained.The morphology,structure,and purity of Fe2O3/CaFe2O4 composite photocatalyst were characterized with SEM,XRD,FTIR,DSC,and TGA.In addition,diatomite loaded Fe2O3/CaFe2O4 composite photocatalyst was obtained.The effect of Fe2O3/CaFe2O4 particles on photocatalytic degradation properties was investigated with UV.100 mL(50 mg/L)of MO(simulated dye wastewater)solution was selected to study its photocatalytic degradation with Fe2O3/CaFe2O4/H2O2.Experimental results showed that the ratio of the composite catalyst,pH value,volume of H2O2,the mass of Fe2O3/CaFe2O4 and the initial concentration of MO affected the degradation efficiency.When pH value,ratio of the composite catalyst,mass of Fe2O3/CaFe2O4,and volume of H2O2 were 6.5,1:1.25,10 mg,and 30 ?L,respectively,the degradation efficiency was ideals.Uder these conditions,the degradation efficiency was 99%when UV irradiation time was 60 min.With increasing the volume of H2O2,the degradation rate also increased,namely,the UV irradiation time reached the degradation efficiency of 99%was less than 60 min.Using HPLC and MS,the degradation process and mechanism of MO was studied.The data of HPLC and MS showed that degradation process might produce to C14H16N3O3S-,C6H7O4S-,C8H11N3,C6H6O2,C4H4O4 and so on.According to the structure of MO,a reasonable degradation mechanism was obtained.100 mL(100 mg/L)of phenol(simulated phenols wastewater)solution was selected to study its photocatalytic degradation mechanism with Fe2O3/CaFe2O4/H2O2.Using HPLC and standard substance,the degradation mechanism of phenol was studied.The data of HPLC showed that degradation process might produce to catechol,hydroquinone,benzoquinone,maleic acid,acetic acid and so on.Reasonably degradation mechanism was inferred from the degradation product.