| Heavy metal pollution is refers to the environmental pollution which caused by heavy metals or their compounds. Water pollution is the mainly form, in addition air pollution and solid pollution. With the rapid development of science and technology, economy get fast development which make our lives convenient, at the same time, it also has a huge influence on our lives. The natural environment suffer from a lot of human activities such as mining, waste gas and water discharge, sewage irrigation, pesticides and processing and commercial manufacturing activities, which cause a large number of heavy metals pollution such as mercury, lead, chromium and others. However, heavy metals pollution does not like the other organic pollution which can reduce their harm by nature itself physical, chemical or biological purification. Due to the characteristics of enrichment, heavy metals are able to constantly enriched within the biosphere, finally they could strongly interact with proteins and enzymes, causing them to lose activity. And they may further enriched in human body, the human will poison when beyond a certain limit such as minamata disease that happened before (mercury poisoning) and bone pain disease (cadmium poisoning). So how to quickly and efficiently detect heavy metal content in the environment has become especially important, heavy metal detection is always from detecting the concentration of heavy metal ion. the mainly test methods include atomic absorption spectrometry, atomic emission spectroscopy, X-ray fluorescence method, etc. But the high operational cost, long analysis time and complex sample pretreatment are common disadvantages of these methods. Considering the universality of heavy metal pollution, we need to build up the fast detection method, electrochemical analysis methods have been widely applied to the direct and rapid determination of heavy metal ion owing to their characteristics such as simple instrumentation, easy preparation and procedure, routine analysis, etc. Nowadays, ion detection of electrochemical analysis methods mainly include ion selective electrode analysis and the stripping voltammetric analysis. This paper focuses on the synthesis and use of the new nanomaterials, and the production of the new ion selective electrode, at the same time, we tried to use the new nanomaterials to stripping voltammetric analysis. Part Ⅰ:studies on nanomaterials modified ion selective electrode1. Studies on the multi-walled carbon nanotubes derivates application on the new Ag(I) ion selective electrodeMulti-walled carbon nanotubes have the characteristics of space configuration and strong rich electronic, which are able to provide appropriate space position and unpaired electron, they can be used as a neutral carrier for the preparation of ion selective electrode. This paper choose N-(1-(pyridin-2-yl)ethylidene)ethane-1,2-diamine to derivative multi-walled carbon nanotube and we built a high performance silver ion selective electrode. Compared with the other electrodes, the performance of our electrode in many aspect have greatly improved. The electrode, with optimum composition, exhibits a good Nernstian slope of58.7±0.3mV decade-1to Ag+ion in the activity range1.0×10-6mol L-1to1.0×10-1mol L-1with a detection limit of9.0×10-7mol L-1, it also exhibits a wide pH range (3.0～8.0) and a relatively fast response time (～15s). In addition, our electrode has a good selectivity and a long life time. In order to further to understanding of the corresponding mechanism of the electrode, This paper adopts the AC impedance technology and UV-Vis spectrum to preliminary study the electrode. The electrode were successfully applied in the potentiometric titration of potassium bromide and determination of silver ions in samples.2. Studies on a new derivatized MWCNTs@SiO2nanocomposites application on Ag(I) ion selective electrodeMulti-walled carbon nanotubes and silicon dioxide compound is selected as the main body material, and then using ethylenediamine derivatives. For the first time a novel carbon paste electrode (CPE) for the detect ion of trace silver (I) was designed by using derivatized silica-coated multi-walled carbon nanotubes (MWCNTs@SiO2) nanocomposites as a neutral carrier. MWCNTs@SiO2have a good coordination ability and ethylenediamine is rich in N atoms, all of these suggests that this material can be as a neutral carrier for the preparation of ion selective electrode. Through the experiment, our electrode exhibit a superior performance, the detection limit is8.0×10-8mol L-1, improving an order of magnitude compared with the first system, which can be attributed to porous silicon dioxide structure. The new nanocomposites was characterized using scanning electron microscope (SEM) and Infrared spectrum and the AC impedance technology was used to discuss the response mechanism. Finally, the developed electrodes were successfully applied in the potentiometric titration of potassium bromide and determination of Cl-ions in different water samples.Part Ⅱ:studies on the anodic stripping voltammetry on a new mercury film electrode 1. studies on anodic stripping voltammetry determination of lead ion based on the Hg(Ⅱ) immobilized graphene oxide composite filmA new Hg modified nanomaterials was firstly prepared, and then we use this nanomaterials as sensitive materials to fabricate Hg/GO modified glassy carbon electrode. The electrode shows very good performance, detection limit reached0.13ng L-1, which showed obvious improvement. We research the electrode preparation from the selection of materials, preparation, characterization, and the experimental conditions. The new nanocomposites was characterized using scanning electron microscope (SEM) and the AC impedance technology, and then deposition potential and deposition time of experimental conditions were discussed in this paper. Under the optimal conditions, the linear calibration curves ranged from5.0ng L-1to70.0ng L-1and0.1μg L-1to10.0μg L-1for Pb2+. Finally, we use standard addition method to determine the concentration of lead ions in different water samples, and the experiment results was compared with test results by atomic absorption spectrometry. |
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