Preparation Of Au-Pd Nanoparticles And Research Of The Detection Of Heavy Metal Ions

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.