砷（Ⅲ）、铬（Ⅵ）在石墨烯修饰电极上的电化学检测
发布时间：2019-05-28 13:24
【摘要】：水环境、土壤、食品及药品等领域重金属污染问题一致受到全社会的普遍高度关注。重金属对人体产生极大危害,而监测是预防和处理的基础和关键环节之一。而在众多重金属离子的检测方法中,电化学方法因其操作简便、便携、灵敏度高、响应迅速,受到众多科研工作者的青睐。而电化学方法中常用的汞膜电极和滴汞电极由于其毒性,限制了其应用,越来越多的科研工作者选择用新的电极来代替。随着纳米科学和纳米技术的发展,石墨烯和碳纳米管由于独特的结构,大的表面积,特殊的形状和物理化学组成等优点受到了很多领域的关注。本文在新型石墨烯修饰钴膜电极上,采用循环伏安法实现了对砷(Ⅲ)的测定;研究了以KNO_3作为增敏剂,用石墨烯修饰铋膜电极测定铬(Ⅵ)的电化学方法;用PW_(12)杂多酸修饰石墨烯电极实现了对Cr(Ⅵ)的测定。内容如下:1、制备石墨烯修饰钴膜电极,通过扫描电子显微镜(SEM)对石墨烯修饰钴膜电极进行了形貌表征。研究发现:石墨烯修饰钴膜电极对砷(Ⅲ)的氧化具有很好的催化性能,产生灵敏的砷(Ⅲ)的氧化峰,氧化峰电流与As(Ⅲ)的浓度呈良好的线性关系,该电极的稳定性和重复性很好。2、制备石墨烯修饰铋膜电极,建立了一种基于Cr(Ⅲ) DTPA(二乙烯三胺五乙酸) NO_3 体系催化作用测定铬(Ⅵ)的电化学方法,通过SEM和EDS对电极表面的沉积产物进行了表征,并探讨了相应的反应机理:溶液中Cr(Ⅵ)在电极表面被还原成为Cr(Ⅲ),然后与溶液中的DTPA络合,再进行阴极化扫描时Cr(Ⅲ) DTPA进一步被还原成Cr(Ⅱ) DTPA,产生灵敏的还原峰,Cr(Ⅱ)又被NO_3 重新氧化,从而对还原产生平行化学(CE)催化作用。铬(Ⅵ)的线性范围为1×10-8~1×10-7 mol/L,检测结果令人满意,具有很高的潜在应用价值。3、制备PW_(12)杂多酸修饰石墨烯电极,并通过实验讨论循环伏安法的扫速、扫描圈数、富集电位等条件对铬(Ⅵ)测定的影响。并在优化的实验条件下对不同浓度的铬(Ⅵ)进行测定,得到的标准曲线线性关系较好,相对标准偏差低,结果令人满意,可为基于杂多酸修饰电极的铬离子传感器的制备提供理论依据。
[Abstract]:Heavy metal pollution in water environment, soil, food and medicine has been paid more and more attention by the whole society. Heavy metals cause great harm to human body, and monitoring is one of the basis and key links of prevention and treatment. Among the many methods for the detection of heavy metal ions, electrochemical methods are favored by many researchers because of their simple operation, portability, high sensitivity and rapid response. However, mercury film electrode and mercury drop electrode, which are commonly used in electrochemical methods, limit their application because of their toxicity, so more and more researchers choose to replace them with new electrodes. With the development of nanoscience and nanotechnology, graphene and carbon nanotubes have attracted much attention because of their unique structure, large surface area, special shape and physicochemical composition. In this paper, arsenic (III) was determined by cyclic Voltammetric method on a new graphene modified cobalt film electrode, and the electrochemical method for the determination of chromium (VI) by graphene modified bismuth film electrode with KNO_3 as sensitizer was studied. Cr (VI) was determined by PW_ (12) heteropoly acid modified graphene electrode. The contents are as follows: 1. Graphene modified cobalt film electrode was prepared and characterized by scanning electron microscope (SEM). It is found that graphene modified cobalt film electrode has good catalytic performance for the oxidation of arsenic (III), and produces a sensitive oxidation peak of arsenic (III). The oxidation peak current has a good linear relationship with the concentration of As (III). The electrode has good stability and reproducibility. 2. Graphene modified bismuth film electrode was prepared and an electrochemical method for the determination of chromium (VI) based on Cr (III) DTPA (diethylenetriamine pentaacetic acid) / NO_3 system was established. The deposition products on the electrode surface were characterized by SEM and EDS, and the corresponding reaction mechanism was discussed: Cr (VI) in the solution was reduced to Cr (III) on the electrode surface, and then complexed with the DTPA in the solution. When the negative polarization scanning was carried out, Cr (III) 鈮，
本文编号：2487102
[Abstract]:Heavy metal pollution in water environment, soil, food and medicine has been paid more and more attention by the whole society. Heavy metals cause great harm to human body, and monitoring is one of the basis and key links of prevention and treatment. Among the many methods for the detection of heavy metal ions, electrochemical methods are favored by many researchers because of their simple operation, portability, high sensitivity and rapid response. However, mercury film electrode and mercury drop electrode, which are commonly used in electrochemical methods, limit their application because of their toxicity, so more and more researchers choose to replace them with new electrodes. With the development of nanoscience and nanotechnology, graphene and carbon nanotubes have attracted much attention because of their unique structure, large surface area, special shape and physicochemical composition. In this paper, arsenic (III) was determined by cyclic Voltammetric method on a new graphene modified cobalt film electrode, and the electrochemical method for the determination of chromium (VI) by graphene modified bismuth film electrode with KNO_3 as sensitizer was studied. Cr (VI) was determined by PW_ (12) heteropoly acid modified graphene electrode. The contents are as follows: 1. Graphene modified cobalt film electrode was prepared and characterized by scanning electron microscope (SEM). It is found that graphene modified cobalt film electrode has good catalytic performance for the oxidation of arsenic (III), and produces a sensitive oxidation peak of arsenic (III). The oxidation peak current has a good linear relationship with the concentration of As (III). The electrode has good stability and reproducibility. 2. Graphene modified bismuth film electrode was prepared and an electrochemical method for the determination of chromium (VI) based on Cr (III) DTPA (diethylenetriamine pentaacetic acid) / NO_3 system was established. The deposition products on the electrode surface were characterized by SEM and EDS, and the corresponding reaction mechanism was discussed: Cr (VI) in the solution was reduced to Cr (III) on the electrode surface, and then complexed with the DTPA in the solution. When the negative polarization scanning was carried out, Cr (III) 鈮，
本文编号：2487102
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