能量色散X荧光仪测量水中重金属的方法研究

发布时间：2018-08-12 12:35

【摘要】：随着现代工农业的快速发展,环境问题日益突出,其中水体重金属污染现状也日益严重,水资源决定着人类的生存和发展。目前分析水体重金属的常见方法主要是分光光度法、原子吸收光谱法(AAS)、电感耦合等离子体发射光谱法(ICPAES)、电感耦合等离子体质谱法(ICP-MS)等,相对其它分析方法,X射线荧光分析方法作为一种成熟的分析方法,其操作简单、分析快速、适合于现场分析,具有其它分析方法无法比拟的优势,但其应用多集中在岩土、合金等固态样品分析领域,如何将X射线荧光分析方法扩展于液体样品领域,实现水体重金属快速、有效的检测也是一个重要的研究课题。本论文将液体固相富集法和X射线荧光薄样分析方法相结合,选择高纯Na型蒙脱石作为固相富集剂,系统性的探讨了富集的影响因素和制样过程,实现了手持式能量色散X荧光仪对水样中Pb、As、Cd、Cr的分析,取得如下的成果:(1)探讨了高纯Na型蒙脱石对液体重金属富集的可行性,研究了相同质量情况下,吸附时间、溶液温度、溶液p H、天然水主成分对高纯Na型蒙脱石富集Pb、As、Cd、Cr的影响,得到了最佳富集效率下的实验反应条件。(2)使用富集抽滤薄样制备工艺结合能量色散X荧光仪进行制样分析,讨论了蒙脱石质量对薄样制备的影响,确定了0.300g为最佳质量;在最佳实验条件下,通过富集不同浓度的重金属混合标液,制备了Pb、As、Cd、Cr标准薄样品,其浓度梯度覆盖(0.01~1.0)μg/m L;优化了能量色散X荧光仪的参数设置,建立了其对水体Pb、As、Cd、Cr的分析方法,针对Pb、As混合体系中谱线重叠现象,选择Pb Lβ作为分析线,减少As对Pb分析的影响,对比了特征峰扣除法与二元线性回归方程对重叠峰的校正效果,减少了Pb对As分析的影响,其各元素标准曲线的线性系数均大于0.878。(3)对建立的分析方法进行准确度和精密度评价,当待测元素的理论浓度大于0.01μg/m L时,其相对误差均小于26%,相对标准偏差RSD(n=10)均小于20%;分析方法中Pb、As、Cd、Cr的检出限分别为7.64μg/L、2.65μg/L、16.2μg/L、8.01μg/L;通过实际水样对该分析方法进行应用性验证,当Pb、As、Cd、Cr加标量为0.5μg/m L时,各样品中元素的加标回收率在70%~120%,其该制样分析方法基本上能够满足水中重金属的分析,对于扩展能量色散X荧光的应用领域具有重要的意义。
[Abstract]:With the rapid development of modern industry and agriculture, environmental problems become more and more prominent, and the pollution status of heavy metals in water bodies is becoming more and more serious. Water resources determine the survival and development of human beings. At present, the common methods for analyzing heavy metals in water are spectrophotometry, (AAS), inductively coupled plasma emission spectrometry (AAS), (ICPAES), inductively coupled plasma mass spectrometry (ICP-MS) and so on. Compared with other analytical methods, X-ray fluorescence analysis (XRF), as a mature analytical method, has the advantages of simple operation, fast analysis, suitable for field analysis and incomparable advantages over other analytical methods, but its application is mostly concentrated in rock and soil. In the field of solid state sample analysis such as alloy, how to extend X-ray fluorescence analysis method to liquid sample field, and how to realize rapid and effective detection of heavy metals in water is also an important research topic. In this paper, the liquid solid phase enrichment method and X-ray fluorescence thin sample analysis method were combined, and high purity Na type montmorillonite was selected as solid phase enrichment agent. The influencing factors of enrichment and the process of sample preparation were systematically discussed. A hand-held energy dispersive X-ray fluorescence spectrometer has been developed for the analysis of PbPb-As-Cddol Cr in water samples. The following results have been obtained: (1) the feasibility of enrichment of liquid heavy metals by high-purity Na type montmorillonite has been discussed, and the adsorption time and solution temperature under the same mass conditions have been studied. The effect of principal components of solution pH, natural water on the enrichment of high purity Na type montmorillonite was studied, and the experimental reaction conditions under the optimum enrichment efficiency were obtained. (2) the preparation process of thin samples was prepared by enrichment and filtration and the energy dispersive X-ray fluorescence spectrometer was used to analyze the sample preparation. The effect of montmorillonite quality on the preparation of thin samples was discussed, and the optimum mass of 0.300g was determined. The concentration gradient was (0.01 ~ 1.0) 渭 g / mL. The parameter setting of the energy dispersive X-ray fluorescence instrument was optimized, and the analytical method of PbAstradizidium cr in water was established. In view of the overlapping phenomenon of spectral lines in the mixture system, Pb L 尾 was selected as the analytical line to reduce the influence of as on the Pb analysis. The correction effect of characteristic peak deduction method and binary linear regression equation on overlapping peaks is compared, and the influence of Pb on as analysis is reduced. The linear coefficients of each element standard curve are all greater than 0.878. (3) the accuracy and precision of the established analytical method are evaluated. When the theoretical concentration of the elements to be measured is greater than 0. 01 渭 g / mL, the relative error is less than 26 and the relative standard deviation (RSD) is less than 20. The detection limit of PbBX / L is 7.64 渭 g / L / L 2.65 渭 g / L / L ~ (16. 2) 渭 g / L ~ (8.01) 渭 g / L respectively. When the scalar amount of PbPbAsC / CdCr is 0.5 渭 g / mL, the recovery rate of the elements in each sample is 70 ~ 120. This method can basically satisfy the analysis of heavy metals in water, and it is of great significance to expand the application field of energy dispersive X-ray fluorescence.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O657.34;X832

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