【作者】 王奎；

【导师】 钱晓良；

【作者基本信息】 华中科技大学 ， 环境科学， 2005， 硕士

【摘要】 本论文主要分为两大部分,第一部分是均匀沉淀法制备羟基磷灰石的研究,第二部分是研究用羟基磷灰石作为载体的负载型二氧化钛光催化剂的制备及性能评价。羟基磷灰石是人体和动物骨骼的主要无机成份,合成磷灰石以其特有的性能可在生物活性、吸附性（生物高分子的分离、精制）、环境净化（重金属离子的捕获、环境催化剂）、脱氟剂等方面有广泛的应用。本论文采用均匀沉淀法制备了纳米级的针状羟基磷灰石,利用XRD、FT-IR、SEM、BET比表面测试,以及粒度测试对其进行了表征,并最终获得了平均粒径为纳米级的针状羟基磷灰石晶体。在制备得到性能良好的羟基磷灰石粉末的基础上,采用压模成型的方法,烧结制得具有一定形状和强度的羟基磷灰石块状载体。光催化氧化法是以n型半导体的能带理论为基础,以半导体作敏化剂的一种光敏氧化法。传统光催化悬浮体系存在反应后TiO₂难以回收以及产生二次污染等问题,很多研究者考虑将光催化剂固定到某种载体上。本文拟通过制备一种与环境友好的羟基磷灰石作为具有吸附性能的新型载体,改进溶胶-凝胶法制备TiO₂的配方,采用浸渍涂覆的方法,制得高效且能多次重复使用的负载型复合光催化剂,并以酸性媒介红B等模拟染料废水为处理对象来进行光催化的活性评价。其中,对光催化剂TiO₂的负载量、染料溶液初始浓度及pH值、染料溶液的种类、载体本身的特点对染料的脱色进行了讨论。并将TiO₂/HAP与P25悬降体系、玻璃载体进行了比较。实验结果表明,当钛酸正丁酯与水的摩尔比为1:2,以冰醋酸作酸催化剂和络合剂,并添加一定量的稳定剂时,既能保证所制备的溶胶长时间不变成凝胶,又能保证催化剂负载牢固; 当煅烧温度为500℃时,TiO₂的主要晶型为锐钛矿结构。将HAP模块在TiO₂溶胶中浸渍涂覆3次,平均负载量为0.171克/片,在15W的杀菌灯下的照射120min后,对100mg/L酸性媒介红B的脱色率可达到92%以上。实验证明了TiO2/HAP对染料具有较高的催化活性,HAP不仅是一种良好的吸附材料,而且对光催化还有一定的促进作用,是一种良好的光催化剂载体。综上所述,采用均匀沉淀法可制得粒径在纳米级的针状羟基磷灰石,对其进行加工定型后,除本身具有一定的吸附效果和光催化效果外,还是一种性能良好的光催化剂载体,这对制备新型环境材料羟基磷灰石以及开发拓展它的新功能方面有一定的应用价值。更多还原

【Abstract】 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.更多还原