Speciation Study of Cr in a Geochemical Reference Material Sediment Series Using Sequential Extraction and XANES Spectroscopy
Speciation Study of Cr in a Geochemical Reference Material Sediment Series Using Sequential Extraction and XANES Spectroscopy
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DOI：
10.1111/j.1751-908x.2014.00292.x
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发表时间：
2015-03
影响因子：
3.8
通讯作者：
Atsuyuki Ohta
中科院分区：
文献类型：
--
作者：
Atsuyuki Ohta
Speciation of Cr in geochemical reference materials was characterised by sequential extraction and X‐ray absorption near‐edge structure (XANES) spectroscopy to identify Cr(III) resulting from the reduction of pollutant Cr(VI). Sequential extraction suggested that the amount of Cr associated with an acetic acid soluble fraction was low; Cr associated with a reducible phase and an oxidisable phase was extracted at 5–10% of the total Cr concentration, and the residual phase was found to be the dominant Cr‐containing fraction. Cr speciation in soil artificially doped with Cr(VI) and sediment samples collected from highly populated and industrialised areas was different from that in naturally occurring materials. Substantial Cr was extracted as a reducible phase (15–30%) and an oxidisable phase (30–60%) for these samples. Through subsequent XANES spectroscopy analysis, the reducible phase was explained by Cr bound to Fe hydroxide, while the oxidisable phase was a mixture of Cr bound to humic substances and Cr hydroxides. That is, Cr(VI) present as a contaminant in sediments and soils was reduced to Cr(III), which then bound to Fe hydroxide and humic substances, precipitating as a hydroxide. Thus, a combination of sequential extraction and XANES spectroscopy allows for effective identification and quantification of the chemical forms of Cr in sediments and soils.
