便携式X射线荧光仪分析土壤中重金属的方法研究

发布时间：2018-07-08 14:01

本文选题：土壤 + 便携式X射线荧光分析仪　；参考：《西安科技大学》2017年硕士论文

【摘要】：近年来,土壤环境随着社会进步受到了严重的污染,对土壤中各种重金属含量的测定是治理和修复污染土壤的关键环节。便携式X射线荧光分析仪相比传统重金属测量仪器具有质量轻、体积小、便于野外携带、检测速度快、可同时测量多种元素等优点,评价仪器的精确度,提高现场快速筛分检测结果的准确性,对重金属含量即时检测具有指导意义。以陕西省商洛市七种不同土壤样品为研究对象,采用原子吸收分光光度计法测量重金属标准值,设置土壤颗粒粒径、土壤含水率和样品测量时间三个实验变量,通过便携式X射线荧光分析仪测量样品Cu、Zn、Pb、Mn含量,主要结论如下:(1)随着土壤样品粒径减小,各元素误差率下降,误差率在20～65目内下降迅速,在65～80目逐渐减小且变化量不到5%。便携式X射线荧光分析仪测量不均匀样品时更容易产生较大误差。(2)土壤水分对于仪器测定存在“稀释”作用,导致数据准确性降低,含水率在10%时已经严重干扰测量结果,为提高测量精度,室内测量时应将土壤样品烘干后再测量,原位测量时应尽可能选择天气晴朗、土壤干燥的现场。(3)随着土壤样品测量时间的增加,4种重金属元素的误差率逐渐减小并趋于稳定。仪器对于含量低在检测限左右的元素,特征X射线的吸收需要更久的时间才能达到稳定和饱和。
[Abstract]:In recent years, the soil environment has been seriously polluted with the progress of society. The determination of heavy metal content in soil is the key to remediation and remediation of contaminated soil. Compared with the traditional heavy metal measurement instrument, the portable X-ray fluorescence analyzer has the advantages of light weight, small volume, easy to carry in the field, fast detection speed, simultaneous measurement of a variety of elements, etc. The accuracy of the instrument is evaluated. It is significant to improve the accuracy of the quick screening detection results in the field and to detect the content of heavy metals in real time. Seven different kinds of soil samples in Shangluo City, Shaanxi Province were used to measure the standard values of heavy metals by atomic absorption spectrophotometer. Three experimental variables, particle size, soil moisture content and sample measurement time, were set. The main conclusions are as follows: (1) with the decrease of soil particle size, the error rate of each element decreases, and the error rate decreases rapidly in the range of 20 ~ 65 mesh. It decreases gradually at 6580 mesh and the variation is less than 5%. The portable X-ray fluorescence analyzer is more likely to produce larger errors when measuring non-uniform samples. (2) soil moisture has a "dilution" effect on the instrument measurement, resulting in a decrease in the accuracy of the data, and the moisture content has seriously interfered with the measurement results at 10%. In order to improve the measurement accuracy, the soil samples should be dried and then measured in the laboratory, and the sunny weather should be chosen as far as possible in the in-situ measurement. (3) with the increase of measuring time of soil sample, the error rate of four heavy metal elements decreased gradually and tended to be stable. For elements with low detection limit, it takes longer for the absorption of characteristic X-ray to be stable and saturated.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X833

【参考文献】