Ferric-assisted Photoelectrocatalytic Degradation Of Rhodamine B

A Co,N,P/TiO2/SiO2/CoFe2O4 composite was synthesized via a sol-gel method,where SiO2/CoFe2O4 represent a core shell magnetic particles consisting of cobalt ferrite and silica.It was applied to the photoelectrocatalytic degradation of Rhodamine B(RhB),where using the xenon lamp as light source,using direct-current main as power sourse and using Na2SO4 as electrolyte.Five kinds of magnetic particle materials have been made by sol-gel method,which is SiO2/CoFe2O4,Ti02/SiO2/CoFe204,Co/Ti02/SiO2/CoFe204,N,P/Ti02/Si02/CoFe2O4 and Co,N,P/TiO2/SiO2/CoFe2O4.And all of them have been applied to the photoelectrocatalytic degradation of Rhodamine B,the result shows that the Co,N,P/TiO2/SiO2/CoFe2O4 have best performance wehter in adsorption of RhB or in photoelectrocatalytic degradation of Rhodamine B.The Co,N,P/TiO2/SiO2/CoFe2O4 was characterized by scanning electron microscope(SEM),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetric Analysis-differential scanning calorimetry(TG-DSC)and vibrating sample magnetometer(VSM).The SEM result shows that the Co,N,P/TiO2/SiO2/CoFe2O4 have more holes in surface,and own a bigger superficial area than TiO2/SiO2/CoFe2O4.The XRD result shows that the TiO2 in Co,N,P/TiO2/SiO2/CoFe2O4 is anatase crystal,and the CoFe2O4 in Co,N,P/TiO2/SiO2/CoFe2O4 Spinel crystal.The XPS result shows that Co、N、P have been successful doped into TiO2,and the proportion of Co,N,P,O,Ti,Si is 1.22%,1.28%,2.05%,59.90%,14.9%and 20.65%in the surface of the material.The TG-DSC result shows that the TiO2in xerogel of the Co,N,P/TiO2/SiO2/CoFe2O4 would change from amorphous to anatase crystal when was heated to 417.7℃,and it would change from anatase crystal to rutile type when was heated to 500～1000℃ The VSM result shows that the Co,N,P/TiO2/SiO2/CoFe2O4 belong to soft magnetic materials,the remanence and coercive force of it is very low.When the Co,N,P/TiO2/SiO2/CoFe2O4 was applied to the photocatalytic,electrocatalytic,photoelectrocatalytic,Fe-assisted photocatalytic,Fe-assisted electrocatalytic and Fe-assisted photoelectrocatalytic degradation of RhB,the results show that all of these degradation reactions followed the pseudo first-degree reaction model,photocatalysis and electrocatalysis have synergistic effect.When Fe was existed in the reactions,the degradation of RhB would be significantly enhanced.When using Co,N,P/TiO2/SiO2/CoFe2O4 as photocatalyst and particle electrode,Fe-assisted photoelectrocatalytic degradation of RhB have been studied.The experimental result shows that under the Na2SO4 concentration as 0.010mol/L,electrolytic voltage as 10V,catalyst dosage as 0.767g/L,initial RhB concentration as 15mg/L and initial pH as 3,the removal rate of Rhodamine B was 98.33%after 50min reaction.