新型电极检测海岸带水体溶解态总铁研究

发布时间：2018-06-19 09:36

本文选题：海岸带水体 + 新型电极　；参考：《中国科学院烟台海岸带研究所》2017年硕士论文

【摘要】：海岸带水体包括河流/沟渠、近岸海域、水库、盐田、湖泊/坑塘等类型,是海岸带区域重要的资源环境要素。铁是生物体所必需的微量元素,对于植物的新陈代谢、叶绿素的合成起着重要作用,而且还是限制海洋初级生产力的关键因素。因此,灵敏、准确检测海岸带水体中的铁对于研究海岸带生物地球化学循环和实现海岸带环境监测来说具有很重要的意义。目前,国际上已经发展了多种检测铁的方法,但是大多数方法需要昂贵和体积大的仪器,从而限制了这些方法在原位分析中的应用,此外一些方法基体干扰比较严重。电化学溶出伏安法具有仪器设备简单、检出限低、检测快速准确、易于自动化、适用于现场快速测定等优点,该方法在痕量铁的分析中占有越来越重要的位置。工作电极是电化学溶出伏安法的核心,目前常用汞电极作为工作电极。但是汞是环境剧毒污染物,在储存、处理方面比较困难。本文针对目前电化学检测铁中存在的问题,构建了新型电极,并将其应用于海岸带河水、海水中溶解态总铁的检测分析。主要研究内容包括以下几方面:1.一步电还原法制备还原氧化石墨烯-金纳米粒子(rGO-AuNPs)修饰电极灵敏检测海岸带水体中的溶解态总铁。本实验采用2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(5-Br-PADAP)为络合剂。该络合剂可在酸性缓冲溶液中与铁离子络合,rGO提供大的比表面积,AuNPs加速电子传递。在最佳实验条件下,该电极测定铁离子的线性范围是0.03~3μmol/L,检出限是3.5 nmol/L。该修饰电极具有良好的重现性和重复性,已经成功应用于实际海岸带水体中溶解态总铁的测定。2.两步法制备还原氧化石墨烯/金膜(rGO/AuF)修饰电极检测海水中的溶解态总铁。海水呈弱碱性,pH为8左右。为了更加准确地检测海水中的溶解态总铁,本实验采用2,3-二羟基萘(DHN)为络合剂,该络合剂适用于在碱性缓冲溶液中与铁离子络合。KBrO3为催化剂,在最佳实验条件下,得到测定铁离子的标准工作曲线。该电极对铁离子的检测线性范围是分段的,分别为0.01~0.1μmol/L和0.1~1μmol/L。该方法的检测结果与伏安极谱仪的检测结果能很好的吻合,并且已经成功应用于海水中溶解态总铁的测定。3.典型海岸带河水中溶解态总铁浓度检测及分布研究。采用金电极为工作电极,5-Br-PADAP为络合剂,5-Br-PADAP与Fe(III)络合速度快(3 min),并且金电极对该络合物具有很好的响应。通过优化测试条件,该方法的线性范围为0.01~1μmol/L,检出限为1.2 nmol/L。该方法测试结果与分光光度法的测试结果基本吻合,并已成功应用于烟台大沽夹河(干湿两季12个站点)溶解态总铁的测定,并探讨了溶解态总铁与溶解氧、盐度等特征常数的关系。金电极结合吸附溶出伏安法有望实现海岸带河水中溶解态总铁的监测。
[Abstract]:Coastal waters include rivers / ditches, inshore waters, reservoirs, salt fields, lakes / potholes and so on, which are important resource and environmental factors in coastal zone. Iron is an essential trace element in organisms, which plays an important role in plant metabolism and chlorophyll synthesis, and is also a key factor limiting marine primary productivity. Therefore, sensitive and accurate detection of iron in coastal water is of great significance for the study of biogeochemical cycle and environmental monitoring of coastal zone. At present, many methods for iron detection have been developed in the world, but most of them require expensive and large instruments, which limit the application of these methods in in-situ analysis. In addition, some methods have serious matrix interference. Electrochemical stripping voltammetry has the advantages of simple equipment, low detection limit, rapid and accurate detection, easy automation and so on. It is suitable for rapid determination in the field. This method plays an increasingly important role in the analysis of trace iron. Working electrode is the core of electrochemical stripping voltammetry, mercury electrode is commonly used as working electrode. However, mercury is a highly toxic environmental pollutant, which is difficult to store and treat. In order to solve the problems existing in the electrochemical detection of iron, a new type of electrode was constructed and applied to the determination and analysis of dissolved total iron in coastal river and seawater. The main research contents include the following aspects: 1. One step Electroreduction method for the sensitive determination of dissolved Total Iron in Coastal Water with reduced Graphene Gold nanoparticles modified electrode. In this experiment, 5-bromo-2-pyridylazo -5-diethylaminophenol (5-Br-PADAP) was used as the complex agent. The complex can provide large specific surface area and AuNPs to accelerate electron transport in acidic buffer solution. Under the optimum experimental conditions, the linear range of the electrode for the determination of iron ions is 0.03 渭 mol / L and the detection limit is 3.5 nmol / L. The modified electrode has good reproducibility and has been successfully applied to the determination of dissolved total iron in coastal water. Reduced graphene / gold film modified electrode was prepared by two-step method for the determination of dissolved total iron in seawater. The pH of seawater is about 8. In order to detect the dissolved total iron in seawater more accurately, the complexing agent of 2o 3-dihydroxynaphthalene (DHN) was used. The complex agent was suitable for complexing with iron ion in alkaline buffer solution. KBrO3 was used as catalyst under the optimum experimental conditions. The standard working curve for the determination of iron ions was obtained. The linear range of the electrode for the detection of iron ions is piecewise, which is 0.1 渭 mol / L and 0.1 渭 mol / L, respectively. The results of this method are in good agreement with those of voltammetry and have been successfully applied to the determination of dissolved total iron in seawater. Detection and Distribution of dissolved Total Iron in typical Coastal Rivers. Using gold electrode as working electrode, 5-Br-PADAP was used as complexing agent. The complexation rate of 5-Br-PADAP with FeOIII was 3 mins, and the gold electrode had a good response to the complex. The linear range of the method is 0.01 渭 mol / L and the detection limit is 1.2 nmol / L. The results of this method are in good agreement with those of spectrophotometry, and have been successfully applied to the determination of dissolved total iron in Dagjiahe River (12 stations in dry and wet fields) in Yantai, and the dissolved total iron and dissolved oxygen have been discussed. The relationship between characteristic constants such as salinity. Gold electrode combined with adsorptive stripping voltammetry can be used to monitor dissolved total iron in coastal water.
【学位授予单位】：中国科学院烟台海岸带研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P734.4

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