Tracking the magnetic carriers of heavy metals in contaminated soils based on X-ray microprobe techniques and wavelet transformation
Tracking the magnetic carriers of heavy metals in contaminated soils based on X-ray microprobe techniques and wavelet transformation
复制标题
基于X射线微探针技术和小波变换追踪污染土壤中重金属的磁性载体
DOI：
10.1016/j.jhazmat.2019.121114
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发表时间：
2020
影响因子：
13.6
通讯作者：
Lu Shenggao
中科院分区：
文献类型：
--
作者：
Yu Xiuling;Wang Yefeng;Lu Shenggao
工业活动中产生的磁性微粒是土壤和粉尘的主要污染源，因为它们通常携带大量的重金属。了解TMPS与污染土壤中重金属的相互作用，有助于追查污染源，探讨磁相富集重金属的机理。本研究采用同步辐射探头技术和多尺度分析方法，对钢铁工业区不同排放源重金属的磁性载流进行了跟踪研究。μ-XRF图谱显示，TMP含有多种重金属，这取决于它们的来源。Fe K边μ-XANES分析表明，在污染土壤中，铁合金、磁黄铁矿和钢渣、火山灰中的TMP是主要的磁相。它们的相对含量在微观上是不同的。多尺度分析表明，与磁相相关的重金属表现出明显的尺度依赖性，这取决于不同磁相的大小、类型和组合。多尺度源解析结果表明，各污染源在不同尺度上的差异较大。热图分析表明，在8-μm尺度下，Co、Cr、Cu和Mn主要来自铁合金，而Ti、Zn和As既来自铁合金又来自于火山灰中的TMP。
Technogenic magnetic particles (TMPs) from industrial activities are major contamination sources of soils and dusts because they usually carry large amounts of heavy metals. The understanding of the association between TMPs and heavy metals in contaminated soils helps to trace the polluting sources and probing into the mechanism of magnetic phases enriched with heavy metals. In this study, we tracked the magnetic carries of heavy metals from different emission sources in steel industrial regions by using the synchrotron-based probe techniques and multiscale analytical methods. The μ-XRF mapping showed that TMPs contained various heavy metals, depending on their sources. The Fe K-edge μ-XANES revealed that the ferroalloy, pyrrhotite and TMPs in steel slag and coal ash were major magnetic phases in contaminated soils. Their relative content varied differently at the microscale. The multiscale analysis revealed that the heavy metals associated with magnetic phases exhibited pronounced scale dependence, depending on the size, type, and assemblage of different magnetic phases. Multiscale source apportionment revealed that the contamination sources varied differently at multiple scales. Heatmap analysis revealed that at 8-μm scale, Co, Cr, Cu and Mn were mainly derived from ferroalloy, while Ti, Zn and As from both ferroalloy and TMPs from coal ash.