Preparation And Characterization Of New Immobilized Photocatalysts Carrier Hydroxyapatite

This dissertation has two parts. The first part is the preparation of hydroxyapatite (HAP). And the second part is the preparation of photocatalytic materials, titanium dioxide. The new immobilized photocatalysts are prepared using HAP as carrier. The activity of the immobilized photocatalysts is investigated by photocatalytic degradation of Acid Mordant Red B. HAP as the main inorganic component of the hard tissues in bones and teeth, is widely studied and used in clinical application to fill or restore damaged human calcified tissue because of its excellent bioactivity, biocompatibility and nontoxicity.Nanograde needle-like crystals are prepared by homogeneous precipitation method starting from Ca(NO3)2·4H2O and H3PO4 . As a result, nanograde needle-like HAP crystals are gained. Influences of initial concentration and sintering temperature treatment on HAP are studied by Scanning electron microscope (SEM),X-ray diffraction (XRD), Fourier transform infrared spectroscopy(FT-IR), Nano-Zetasizer90,and so on . Photocatalic oxidation is a kind of photosensitive oxidation method using n-styled semiconductor as a photocatalyst, which is based on the energy band theory of this photocatalyst. But the conventional suspended reaction system has many faults such as difficult to recycle after the TiO2 powder used and so will cause sec-pollution to water, many researchers have thought of coating TiO2 on a kind of carrier. In this dissertation, new immobilized photocatalysts are prepared using HAP as carrier. And the activity of the immobilized photocatalysts is investigated by photocatalytic degradation of Acid Mordant Red B.The loaded weight of TiO2, the initial concentration and pH of dye wastewater, different kinds of dye wastewater, and different sintering temperature treatment to HAP are dissussed. And we also compare the activity of the TiO2/HAP and Degussa P25. The result shows that the molar ratio of Ti (Bu--n) and water should better be controlled to 1:2 to protect the sol from becoming gel for a relative long time and also to assure firm coat. In the preparation, HAc can work as acid catalyst and chelate agent as well. It is calcined at 500℃ for 2h ,coated photocatalyst with 3 coating layers ,the degradation of 100mg/L Acid mordant red B rate for 2h is more than 92%. The experimental results have indicated that nanograde needle-like crystals are prepared by homogeneous precipitation method. Not only the adsorption of HAP, but also the excellent carrier of immobilized photocatalysts.