Preparation Of Composite TiO_Photocatalyst With Ferrofluid And Its Pollutants Degradatrion Properties

In recent years, there has been great concern over the many serious environmental problems such as toxic compounds in polluted water and air. Since Fujishima and Honda first reported the effect of photosensitization of TiO2 electrode on the electrolysis of water into H2 and O2, TiO2, as a new kind of environmental protection material, has received much attention and been widely studied in the field of the photodecomposition of water and photodegradation of organic pollutants in air and water. However, the removal of TiO2 catalyst from reaction system encountered great difficulty due to its work in a form of suspension of TiO2 powder in liquid phase, which requires higher cost for recovering ultrafine TiO2 powders from reaction solutions. Superparamagnetic nanoparticles is a type of nanoparticles with unusual magnetic response and ultrasmall particle size. In this case, the thermal energy is sufficient to overcome any preferential orientation of the moment in the superparamagentic nanoparticle when the external field is zero or weak enough, therefore no magnetic response is observed, while the particle can present great magnetic response once the external field is attached and move with external field. Hence, producing a new catalyst combining this kind of superparamagnetic nanoparticle and TiO2 nanoparticles, that is, a magnetic separable photocatalyst, is of emerging interest.In this thesis, superparamagnetic Fe3O4 nanoparticles in the form of ferrofluid (supplied by Harbin Normal University) was selected as the magnetic nanocore to produce homogeneous coated Fe3O4-SiO2 support using the well-known st?ber method. Then monodispersed TiO2/Fe3O4-SiO2 nanocatalyst with typical"core-shell"structrue was successfully obtained through sol-gel process from Ti(OBu)4. Moreover, controllable immobilization of TiO2 nanocatalyst on Fe3O4-SiO2 magnetic nanocores was performed by pre-treating Fe3O4-SiO2 support in an ethanol/deionized water mixture heated to reflux. The prepared magnetic separable TiO2 nanocatalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupled plasma (ICP) spectrophotometric method, UV-vis spectrometer, and Fourier-transform infared spectroscopy(FTIR) methods. The photocatalytic activity was evaluated by monitoring the photodegradation of PR dye and naphthalene, respectively.