Preparation Of Magnetically Separable TiO₂ Photocatalysts By The Method Of Plasma Assisted

In the degradation of organic pollutants, nano TiO2–photocatalyst is a widely used photocatalyst due to its higher specific surface area and high photocatalytic activity. However it is difficult to separate the photocatalyst from treated system. Therefore, TiO2 was be loaded on hollow glass microbeads,zeolite,activated carbon etc, prepared laden photocatalyst, however, the activity of TiO2 photocatalyst was reduced because of the smaller surface area of carrier and the decreases of laden photocatalysts. In addition, the low efficiency of sunlight also greatly limits its practical applications. The nano-magnetic particles were applied to solve the difficulty of photocatalyst separation from the treated water by applying an external magnetic field. Comparing with other carriers, TiO2 magnetic photocalalyst has become a new hotspot. To further enhance photocatalytic activity of the TiO2 photocatalyst, develop the range of spectral, many methods had been used to modify TiO2 photocatalyst, and had made great progress. One of them, plasma technology was applicated in preparation and modification of materials, and opened up the new areas of material technics.In this paper, the core-shell CoFe2O4/ TiO2 magnetic nano-photocatalysts were prepared by hydrolysis of titanium tetrachloride precursor in the presence of the CoFe2O4/TiO2 magnetic photocatalysts. The core-shell structure of the CoFe2O4/TiO2 magnetic photocatalysts were dried at 100℃and calcined at 350℃for 2h. The prepared photocatalysts were easy to be separated from polluted water by using an external magnetic field and showed high catalytic activity for the degradation of methyl orange in water under UV, and could be recycled. In order to broaden spectral response range of visible light about the catalyst's response and improve the use ratio of sunlight. In this paper, a core-shell CoFe2O4/TiO2 magnetic nano-photocatalyst was prepared by hydrolysis of titanium tetrachloride in the presence of the CoFe2O4 magnetic particles and modified by cold plasma. The magnetic property of the samples was characterized by Vibrating Sample Magnetometer (VSM) analysis. The CoFe2O4/TiO2 magnetic nano-photocatalyst has fairly good magnetic property. The X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scan electron microscopy (SEM), Ultraviolet–visible (UV–Vis) technique and Fourier transform infrared spectrometer (FTIR) were used to analyze the phase structure, size and spectrum response range of the samples. The XRD indicated the anatase TiO2 was formed when CoFe2O4/TiOX modified by plasma. The size of CoFe2O4 particles was about 20 nm. The diameter of CoFe2O4/TiO2 particles is in the range of 30-40 nm. So the shell of TiO2 enwraps closely around the core and the thickness is in the range of 5-10 nm. The UV–Vis spectrum revealed a red shift of the absorption edge to the visible-light region than that of the pure TiO2. Methyl orange was used to investigate the photo-degradation activity of the nano-photocatalysts. The results showed that the photocatalytic activity of CoFe2O4/TiOX modified by plasma is better than that without plasma.