| With the rapid development of socialist modernization, not only the economy develops rapidly, but also brings a series of problems in other areas. Especially the pollution problem of inorganic heavy metal ions is particularly prominent among the environment problems. As everyone knows, water resources are the basic resources of the earth. It is an important role in promoting the civilization development of human society. The heavy metal is a highly toxic substance, which has the characteristic that is difficult to be degraded into a non-toxic and harmless substance. With the continuous enrichment of the food chain, the physical and mental health of human beings, the biosphere of plants and animals, and other aspects are posed a huge threat. So it is very important to find a simple, fast and efficient analytical method for the detection of inorganic heavy metal ions. So far, many methods have been applied to the detection of inorganic heavy metal ions in water environment. The electrochemical analysis method is favored because of the experimental operation is simple and low cost, fast detection speed, high sensitivity and good selectivity, low detection limit characteristics. But most of the nano-materials are prepared by the complex of noble metal and the complicated synthesis method. Based on the principle of saving and environmental protection, it becomes a trend to find a kind of low cost, simple synthesis method and a better response to the inorganic heavy metal ions in water environment.Carbon materials have been widely concerned and applied to many fields in the world due to its unique characteristics and structure. Common carbon materials are:carbon nanotubes, graphene, carbon microspheres and so on. Carbon microspheres (CMSs) were widely used in many fields because of its low cost, good conductivity and easy synthesis and other characteristics. Amino groups on the surface of amino functionalized carbon microspheres have good affinity for heavy metal ions, so the adsorption capacity of the amino group is increased by the adsorption of heavy metal ions. Based on the above problems, the main work and innovative points of this paper are as follows:First, we synthesized successfully the amino functionalized carbon microspheres with uniform size (NH2-CMS) and make NH2-CMS as the material of the electrode assembly. Under the optimal experimental conditions, we detected simultaneously and individually four heavy metal ions including Cd(II)、Pb(II)、Cu(II) 、Hg(II) by anodic stripping voltammetry and the results showed excellent sensitivity and selectivity. After, we compared the sensitivities and detection limits of the electrochemical detection of inorganic mercury ion by the assembled electrode of the bare glass carbon, the carbon microsphere and the amino carbon microspheres. It was found that the electrochemical response of Hg(II) was the best by the assembly of the amino functionalized carbon microspheres. Then we carried out the electrochemical analysis of Hg(II) in real samples. It had a good response and the recovery rate was standard. Finally, the theoretical basis for the electrochemical detection of four heavy metal ions was presented based on the adsorption experiments.Second, gold nanoparticle-carbon microspheres were synthesized successfully by a simple method on the basis of amino functionalized carbon microspheres. The electrochemical analysis of Hg(II) by using the square wave anodic stripping voltammetry was studied. According to the results of electrochemical detection, the sensitivity and detection limit of Hg(II) were improved, which showed that gold nanoparticles had higher electrochemical activity in the catalytic oxidation. Finally, we tested the stability of the gold nanoparticle-carbon microspheres assembly electrode. The result was that the relative standard deviation (RSD) of peak current was very low. It indicated that gold nanoparticle-carbon microspheres had good stability and can be reused. |
PDF Full Text Request