基于紫外原子荧光法的汞浓度测量系统研究

发布时间：2018-06-12 14:31

本文选题：紫外荧光法 + 汞　；参考：《华北电力大学》2017年硕士论文

【摘要】：随着世界经济以及生产力的发展,环境污染问题也越发地引起关注。由于极易挥发、极易扩散并有生物富集性,汞成为一种世界性的污染物。造成汞污染的最主要的原因是燃煤。在全球范围内,我国的汞污染尤为严重。当前国内还没有可靠的电厂烟气汞排放含量监测体系,烟气中总汞的监测还是一片空白。总汞连续监测方法的研究对于制定国内电厂总汞排放限值意义重大。目前,多相汞浓度测量的主要方法有冷蒸汽原子吸收光谱法(CVAAS)、冷原子荧光法(CVAFS)、原子发射光谱法(AES)等,在诸多方法中,原子荧光光谱法因测定灵敏度高、检出限低,基本无基体干扰等优点而具有非常高的优越性。本文基于紫外荧光光谱法对测量汞浓度的系统做出了研究,主要工作及成果如下:(1)各数量级浓度汞标准溶液的制备方法研究。由于ppb级别的汞溶液极不稳定,所以在配制、储存过程中需加入保护剂以防损失,在充分研究及大量实验后,确定了配制汞标准溶液的理想方案。(2)汞标准溶液还原的实验方案制定。该方案的制定决定了反应结果的合理性及准确性。在实验系统、实验条件等因素共同影响下,确定了一套汞溶液还原反应-尾气排放处理的实验系统。(3)原子荧光测汞系统的研制。采用自主设计的激发光源-暗室系统和内部循环汞蒸汽发生设计,成功地研制出高灵敏原子荧光测汞系统。该系统具有灵敏度高、检出限低、样品前处理简单等优点,实现了液体样品中超痕量汞的直接测定。自主设计的内循环-外排放双工作模式系统,不仅具有安全高效的优点,又能够提供很高的准确性及封闭性。所懫用的激发光源-暗室系统,不仅保证了实验人员的身体安全,而且可有效的减少光传输过程的损失,消除了杂散光的干扰。(4)原子荧光测汞系统测定液相中超痕量的汞。懫用研制的原子荧光测汞系统,在一系列实验后,优选出更加合理的实验条件,并在优化的条件下成功地测定了纯净水、北京海淀自来水和地表水中超痕量汞的含量。结果表明,本测量系统可以很好地应用于测量水中的超痕量汞含量。并通过安大略法在张家口沙岭子电厂实地取样烟气测量,测量结果与LUMEX测量结果无显著差异,验证了本测量系统在实际应用中的作用,并对测量结果进行了分析。
[Abstract]:With the development of world economy and productivity, environmental pollution has become more and more concerned. Mercury has become a worldwide pollutant due to its high volatilization, easy diffusion and bioaccumulation. The main cause of mercury pollution is coal burning. Globally, mercury pollution is especially serious in China. At present, there is no reliable monitoring system for mercury emission from power plant flue gas, and the monitoring of total mercury in flue gas is still a blank. The study on the method of continuous monitoring of total mercury is of great significance in determining the limit of total mercury emission in domestic power plants. At present, the main methods for measuring the concentration of multiphase mercury include cold vapor atomic absorption spectrometry, cold atomic fluorescence spectrometry, atomic emission spectrometry, etc. The detection limit of atomic fluorescence spectrometry is low because of its high sensitivity. It has many advantages such as no matrix interference and so on. In this paper, the system of mercury concentration measurement is studied based on UV fluorescence spectroscopy. The main work and results are as follows: 1) the preparation method of mercury standard solution with different concentrations. Because the mercury solution of ppb grade is very unstable, the protective agent should be added in the preparation and storage process to prevent the loss. After full study and a lot of experiments, The experimental scheme of mercury standard solution reduction was established. The formulation of the scheme determines the rationality and accuracy of the response results. Under the influence of experimental system, experimental conditions and other factors, a set of experimental system of mercury solution reduction reaction-tail gas emission treatment, atomic fluorescence spectrometry (AFS) was developed. A highly sensitive atomic fluorescence system for mercury detection was successfully developed by using the self-designed excitation light-dark chamber system and the internal cyclic mercury vapor generation design. The system has the advantages of high sensitivity, low detection limit, simple sample pretreatment and so on. The direct determination of ultra-trace mercury in liquid samples has been realized. The self-designed dual-mode system of internal circulation and external discharge not only has the advantages of safety and efficiency, but also can provide high accuracy and closure. The excitation light-dark chamber system not only ensures the safety of the experimenter, but also can effectively reduce the loss of light transmission and eliminate the stray light interference. 4) the atomic fluorescence spectrometry is used for the determination of ultra-trace mercury in liquid phase. After a series of experiments, more reasonable experimental conditions were selected, and the content of ultra-trace mercury in pure water, Beijing Haidian tap water and surface water was successfully determined under the optimized conditions. The results show that the system can be applied to the determination of ultra-trace mercury in water. The results of field sampling flue gas measurement by Ontario method in Zhangjiakou Shalingzi Power Plant are not significantly different from those of LUMEX. The function of this measurement system in practical application is verified, and the measurement results are analyzed.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X773;X831

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