基于同步辐射的硬X射线荧光技术分析污染土壤中重金属分布

Analysis of Heavy Metal Distribution in Polluted Soil Using Synchrotron Radiation Hard X-ray Fluorescence Technology

  • 摘要: 基于同步辐射技术的微束X射线荧光(μ-XRF)分析具备原位分析样品的元素组分,化学特性,物质结构及其二维分布等的能力,可更加直观地揭示目标元素在复杂体系中的分布状态。利用传统的化学消解与原位μ-XRF技术相结合的方法,探测锡矿山土壤中多种元素的含量和空间分布,采用线性回归方法分析各元素的相关性。结果表明,供试土壤Sb和As含量较高,分别为6 681和878 mg•kg-1,μ-XRF分析结果表明土壤中Fe、Mn分别与As的空间分布相关性较好,决定系数(R2)达到0.225 8和0.181 1,更直观地揭示了As在土壤中以铁锰结合态为主。μ-XRF技术的应用原位直观地揭示了土壤中多种元素的分布关系,为综合评价和预测土壤中重金属的环境行为以及发展污染土壤修复技术等提供理论支持。

     

    Abstract: Synchrotron-radiation-based micro-beam X-ray fluorescence (μ-XRF) technology can be used to analyze in-situ elemental composition, chemical properties, and material structure of samples and bi-dimensional distribution of the elements in the samples, thus making it possible to intuitively observe distribution of target elements in a complex system. Using the traditional acid digestion in combination with the state-of-art μ-XRF technology, the contents and spatial distribution of metal (-loids) in a polluted soil were investigated. The soil was collected from a tin mining area in Hunan Province, China, which is one of the largest Sb mines in the world, and has long been famed as the “World Antimony Capital”. In addition, linear regression analysis was performed for relationships between elements in the soil. Results show that the soil was quite high in Sb and As, being 6 681 and 878 mg•kg-1, respectively, in concentration. Moreover, μ-XRF revealed that As was closely related separately to Fe and Mn, in spatial distribution with determinant coefficient reaching 0.225 8 and 0.181 1, which more intuitively displayed that As in the soil was dominantly Fe-Mn-bound As. Comparing with the traditional acid digestion method, the μ-XRF method is able to intuitively expose in-situ relationships between the elements in distribution in the soil, so it is an useful tool in overall assessing and predicting environmental behaviors of heavy metals in the soil, which in turn provides theoretical support to the development of technologies to remedy polluted soils.

     

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