| In the degradation of organic pollutants,Nano-TiO2 slurries are generally considered as more efficient than immobilized TiO2 since slurry TiO2 offers higher specific surface area.However,the TiO2 nanoparticles are hard to be recovered from slurries after treatment.Magnetic core-shell TiO2 photocatalyst,which is obtained by depositing a TiO2 layer onto magnetic materials,keep the high photocatalytic activity of TiO2 nanoparticls and is easy to be separated under an applied external magnetic field.Industrial wastewater is difficult to be degraded.Photocatalysis by TiO2 are very promising methods to degrade dye wastewater for cheaper,highactivity,no secondary pollution.At present,the research about TiO2 form has two tendency;one is TiO2 powder,another is TiO2 membrane.Compare with TiO2 membrane,TiO2 powder has the larger surface.Therefore,its photocatalytic activity is higher.But TiO2 powder is not perfect for recovering from treated water system.Magnetic photocatalysts were synthesized by coating a magnetic core with a layer of photoactive titanium dioxide.This magnetic photocatalyst is for use in slurry-type reactors in which the catalyst can be easily recovered by the application of an external magnetic field.The study background and application perspectives of supported photocatalysts and magnetic photocatalysts are introduced.Photocatalytic principle of Nano-TiO2 is also reviewed.Based on adequate study of background knowledge,we choose the preparation and magnetism as well as photocatalytic properties ptudy of pagnetism TiO2/SiO2/γ-Fe3O4 to research.In this paper,the magnetic cores Fe3O4 have been prepared with FeC13·6H2O and FeSO4·7H2O.Then SiO2/Fe3O4 particles have been prepared through precipitation method,and in this reaction the Si(OC2H5)4 is the main material,the Fe3O4 is the magnetic core.At lastγ-Fe2O3/SiO2/TiO2 coated particles have been prepared with C16H36O4Ti and SiO2/Fe3O4 as precursors by Sol-Gel method.In order to improve the photocatalytic degradation activity ofγ-Fe2O3/SiO2/TiO2 for rhodamine B,the conditions of preparing were selected and the better photocatalytic activities were received.Its morphology and structure were characterized by XRD and other equipments.The result indicated;the photocatalytic activity ofγ-Fe2O3/SiO2/TiO2 is better than those TiO2 and Fe3O4/TiO2,Its photocatalytic activity just a little worse than/SiO2/TiO2.The samples ofγ-Fe2O3/SiO2/TiO2 have good magnetism and it is easy to reclaim.
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