【作者】 尹立兵；

【导师】 章桥新；

【作者基本信息】 武汉理工大学 ， 材料学， 2012， 硕士

【摘要】 重金属对人体健康有很大的毒害作用,其对环境的污染是一个全世界范围的问题。例如,砷是一种剧毒物质,在许多国家已发现饮用水中含有砷污染物。因此,现在急需研究出一种快速、灵敏和有选择性检测重金属离子的方法。许多技术已被用于重金属离子的检测,在这些方法中,电化学技术是最有前景的检测技术,其具备的特点有成本低、较高的检测精度和较快的检测速度。在电化学分析领域,纳米金属粒子表现出许多先进的功能特性,因此,纳米金属粒子修饰电极已被用于电化学检测。纳米材料修饰电极制备的方法有很多,修饰电极的性能也受许多因素的影响。本论文制备了Au-Pd纳米粒子,研究其对重金属离子的检测,主要工作如下：(1)实验中采用水热合成技术制备Au-Pd纳米粒子,并对Au-Pd纳米粒子的形貌和组成结构进行了相关的表征,包括扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、能量弥散X射线谱(EDS),以及X射线衍射(XRD)等分析。为了优化实验参数,实验中在不同的实验条件下制备Au-Pd纳米粒子,例如不同的温度和时间,研究了聚乙烯吡咯烷酮(PVP)对Au-Pd纳米粒子形貌和尺寸的影响。实验中研究了以镍片为基体在其表面制备Au-Pd纳米粒子的方法,以及氢氧化钠在Au-Pd纳米粒子制备过程中的作用。(2)以超声分散法对Au-Pd纳米粒子进行预处理,并对电极进行磨平和抛光处理。采用直接滴涂法将Au-Pd纳米粒子引入电极表面制备纳米修饰电极,并对Au-Pd纳米修饰电极进行电化学表征,包括循环伏安法(CV)、线性扫描伏安法(LSV)、电化学阻抗(EIS)等分析。这将进一步完善修饰电极的制备工艺,提高修饰电极的性能。(3)实验中将Au-Pd纳米修饰电极用于重金属离子的检测,采用方波阳极溶出伏安法,以该电极分别对As3+和Cu2+进行检测。实验结果表明,As3+和Cu2+在电极表面上都有各自的溶出峰,且都具有良好的线性关系。此外,该电极被用于As3+和Hg2+的同时检测,由其结果可知,Hg2+的加入对As3+的检测没有干扰,即该电极对As3+的检测具有很好的选择性。这将拓展纳米材料的应用,同时为重金属离子的检测提供了一种检测方法。更多还原

【Abstract】 The heavy metals are toxic for the human health,and the pollution of the natural environment by heavy metals is a worldwide problem. For example,the arsenic is a highly toxic element, and arsenic contamination of groundwater has been reported in many countries. Therefore,it is very essential to develop fast, sensitive, and selective analytical methods for the detection of heavy metals. Many techniques have been used for the detection of heavy metals. Among of these methods, electrochemical techniques are potentially the most promising techniques,as they are cheap and provide very accurate measurements with fast analysis time. Nanometallic materials have shown many advantageous functional properties in the field of electrochemical analysis, so the nanometal particles modified electrodes have been used for the electroanalysis. A lot of methods are used in the prepation of nanomaterials modified electrodes, the performance of the modified electrodes also be affected by a lot of factors.The paper has prepared the Au-Pd nanoparticles, and researched the performance of it in the detection of heavy metal ions, the main work of this paper has completed as follows.(1) In the experiment, the hydrothermal synthesis technology was used for the preparation of Au-Pd nanoparticles, the shape and composition of Au-Pd nanoparticles were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). In order to optimize experiment parameters, the Au-Pd nanoparticles were prepared in the different conditions, such as different reaction temperature and time, and had researched the influence of polyethylene pyrrole (PVP) to the morphology and size of Au-Pd nanoparticles. Moreover,the Au-Pd nanoparticles were prepared on the surface of nickel piece,and had researched the effect of sodium hydroxide(NaOH) in the reaction.(2) The Au-Pd nanoparticles were preprocessed by the use of ultrasound dispersing, and the electrode was grinded and polished. The modified electrode was prepared by directly dropping Au-Pd nanoparticles on the surface of electrode. The electrochemical properties of the modified electrode were characterized by cyclic voltammetry(CV), linear sweep voltammetry(LSV), and electrochemical impedance(EIS). This will further perfect the preparation of the modified electrodes, and improve the properties of the modified electrode.(3) The Au-Pd nanoparticles modified electrode was used in the electrochemical detection of heavy metal ions, it has been used in the separate detection of As3+and Cu2+with square wave anodic stripping voltammetry(SWASV). The results showed that As3+and Cu2+have their stripping peak in the detection with a good correlation. In addition,the modified electrode was also used in the simultaneous detection of As3+and Hg+, the results showed that the electrode can detect As3+even in the presence of Hg2+without any interference, so that the electrode showed a good slective detection of As3+. This will develop the application of nanometer materials,and provide a new method for the detection of heavy metal ion.更多还原