羟基磷灰石的制备及其性能研究

【作者】 于凯；

【导师】 李怀祥；

【作者基本信息】 山东师范大学 ， 物理化学， 2011， 硕士

【摘要】 近年来,羟基磷灰石（HA）作为一种新型的纳米生物材料得到了国内外的广泛关注。羟基磷灰石规则的立体化学结构和良好的生物相容性使其在催化、蛋白质分离、生物传感等领域倍受瞩目,为高灵敏的生物检测和传感器小型化方面的应用开辟了新的道路。而且基于羟基磷灰石较强的吸附能力和独特的多吸附位点使其在使其处理含重金属离子的废水、污染土壤等方面也得到了迅速的发展。本论文在综述部分概述了羟基磷灰石独特的立体化学机构,比较了几种常规制备羟基磷灰石的方法,详细介绍了羟基磷灰石吸附重金属离子的机制以及影响因素,论述了羟基磷灰石在生物传感中的应用,展望了羟基磷灰石的应用前景。实验研究包括以下几个内容:1. HA修饰铂电极上对葡萄糖的生物传感采用双电位阶跃法在铂电极上电沉积制备羟基磷灰石涂层,研究葡萄糖氧化酶（GOD）在该修饰电极上的直接电化学行为;探讨制备的Nafion-GOD-HA-PVA（聚乙烯醇）/Pt复合电极对葡萄糖的电催化氧化作用,采用计时电流法测定溶液中葡萄糖的含量,并测试了此传感器的稳定性和重现性。实验表明在Nafion-GOD-HA-PVA/Pt内, GOD呈现出很好的直接电化学性质,说明羟基磷灰石和Nafion良好的协同作用,有利于GOD的固定,可以促进GOD的电子转移,保持GOD的活性,并对葡萄糖的氧化具有极好的催化作用。该葡萄糖传感器对葡萄糖的电流响应较快检测线性范围为0.02⁰.52mmol/L,检测限为1.82μmol/L,灵敏度为56.90mA·L·mol^-1。此外,该传感器还具有良好的稳定性和重现性。2. HA修饰多孔二氧化钛对葡萄糖的生物传感采用阳极氧化法制备多孔二氧化钛,溶胶-凝胶法制备羟基磷灰石,并用羟基磷灰石- Nafion复合膜将葡萄糖氧化酶有效地固定于多孔二氧化钛上,将这种制得的复合电极Nafion/GOD-HA-PVA/TiO₂/Ti对不同浓度的葡萄糖溶液进行检测,考察此复合电极的最佳工作电压,采用计时电流法测定溶液中葡萄糖的含量。并测试了此传感器的稳定性和重现性。实验表明,在Nafion/GOD-HA-PVA/TiO₂/Ti内,羟基磷灰石、多孔二氧化钛和Nafion良好的协同作用,有利于GOD的固定,保持GOD的活性。在最佳工作电压-0.42V下,此复合电极对葡萄糖的氧化具有良好的催化作用。3. HA吸附水溶液中Zn²⁺的研究采用液相沉淀法制备羟基磷灰石,研究羟基磷灰石对Zn²⁺的吸附作用,主要考察Zn²⁺初始浓度、温度、pH值及反应时间对去除效率的影响,并探讨HA的吸附机理。实验表明,利用液相沉淀法合成的HA,对Zn²⁺有较强的吸附作用,是良好的新型吸附剂;HA对水溶性Zn²⁺的最佳吸附条件为:pH为6.5,反应时间为50min,温度为35℃;HA对溶液中重金属离子的吸附大致可分开始阶段的表面吸附以及后期阶段离子交换吸附。更多还原

【Abstract】 Hydroxyapatite （HA） as a new type of nano-biological materials has been widespread concern at home and abroad in recent years. Hydroxyapatite-dimensional chemical structure of the rules and good biocompatibility make it in the catalysis, protein separation, high-profile areas such as bio-sensing for sensitive biological detection and sensor miniaturization has opened up new applications road. Based on the strong adsorption of hydroxyapatite and unique multi-adsorption sites, HA has been used to deal with waste water containing heavy metal ions, contaminated soil, etc.This paper outlined the review part of the unique stereochemistry of hydroxyapatite bodies, compared with several conventional method of preparing hydroxyapatite, described in detail the adsorption mechanism of heavy metal ions by hydroxyapatite and discussed influence factors. Hydroxyapatite application in biological sensing had been looked forward. Experimental studies include the following elements:1. HA modified platinum electrodes for glucose biosensorA novel glucose biosensor was constructed by immobilizing the glucose oxidase（GOD） on hydroxyapatite（HA）-polyvinyl alcohol（PVA） composite film electrodeposited on platinum electrode and applied to the highly selective and sensitive determination of glucose. The GOD adsorbed onto the HA-PVA composite film exhibits a pair of well-defined nearly reversible redox peaks and fine catalysis to the oxidation of glucose. The results demonstrated that with the cooperation of HA-PVA and Nafion, which can enhance the electrochemical activity of GOD and promote electron transfer, the composite film played an important role in enhancing the stability and sensitivity of the biosensor, the decreased reduction current was linear with the concentration of glucose in the range of 0.02- 0.52 mM. The results demonstrated that this modified electrode can achieve highy sensitive determination of glucose.2. HA modified TiO₂ for glucose biosensorA glucose biosensor was constructed by immobilizing the glucose oxidase（GOD） on hydroxyapatite prepared by sol-gel method on TiO₂ prepared by anodic oxidation to the highly selective and sensitive determination of glucose. In this experiment,we optimized the best work voltage of this composite electrode by chronoamperometry of glucose in the solution and tested the sensor stability and reproducibility. Within the Nafion/GOD-HA-PVA/TiO2/Ti structure, there was a good synergy between hydroxyapatite, titanium dioxide nanotubes and Nafion, to keep the activity of GOD. This composite electrode showed excellent catalyst for the oxidation of glucose at -0.42V voltage.3. HA adsorption of Zn²⁺ in aqueous solutionIn this experiment, we prepared hydroxyapatite by liquid phase precipitation and studied the adsorption of Zn²⁺, mainly on the initial concentration of Zn²⁺, temperature, pH, and reaction time on removal efficiency and adsorption mechanism of HA.Experimental results showed that HA synthesized by liquid phase precipitation was a good new adsorbent to the adsorption of Zn²⁺. The optimized adsorption conditions for water-soluble Zn²⁺ were as following: pH 6.5, reaction time 50min, the temperature 35℃. HA on the adsorption of heavy metal ions in solution can be divided into roughly the beginning of the late stage of the surface adsorption and ion exchange adsorption.更多还原