Characterization and acid-mobilization study for typical iron-bearing clay mineral
Characterization and acid-mobilization study for typical iron-bearing clay mineral
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典型含铁粘土矿物的表征及酸动员研究
DOI：
10.1016/j.jes.2018.04.012
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发表时间：
2018
影响因子：
6.9
通讯作者：
Jianmin Chen
中科院分区：
文献类型：
--
作者：
Zhenzhen Wang;Rui Li;Lulu Cui;Hongbo Fu;Jun Lin;Jianmin Chen
本研究对5种标准粘土样品中的铁形态进行了表征。然后在酸性介质中测量这些粘土中的铁动员。为了进行比较，还观察了一种市售的亚利桑那试验粉尘（ATD）。结果表明，土壤中游离铁含量普遍低于粉尘气溶胶。粘土的组成以铝硅酸盐晶格中的结构铁为主。粘土的铁溶解度依次为KGa-2 > SWy-2 > CCa-2 > IMt-2 > NAu-2。通过Mössbauer光谱和透射电子显微镜（TEM）分析，发现溶解后黏土颗粒的Fe（II）分数和Fe/Si比发生了变化，表明总Fe溶解度取决于铝硅酸盐晶格中存在的Fe原子态。KGa-2和SWy-2中的Fe很可能取代碱性元素成为铝硅酸盐中离子键保持的层间离子，更容易溶解。然而，在铝硅酸盐矿物中，NAu-2中的铁更容易被强共价键结合，而铝硅酸盐矿物的可溶性较低。ATD中高可溶性的Fe不仅与相当一部分Fe（II）的溶解有关，而且还与ATD粘土部分中的Fe键主要以离子键形式存在有关。TEM图像显示，反应后的粘土颗粒中聚集颗粒较少，残余颗粒中存在纳米颗粒聚集体和富铁/ s的微小颗粒。
In this study, iron speciation in five standard clay samples was characterized. Iron mobilization from these clays was then measured in acidic media. For comparison, a commercially available Arizona test dust (ATD) was also observed. The results showed that the free-Fe contents of clays were commonly lower than that of dust aerosols. The components of clays were dominant by the structural Fe held in the aluminosilicate lattice. The iron solubility of the clays were in the order of KGa-2 > SWy-2 > CCa-2 > IMt-2 > NAu-2. Based upon the Mössbauer spectrum and transmission electron microscopy (TEM) analysis, the Fe(II) fraction and the Fe/Si ratio of clay particles changed after dissolution, suggesting the total Fe solubility depended on the Fe atom states existing within the aluminosilicate lattice. The Fe in KGa-2 and SWy-2 was most likely substituted for alkaline elements as the interlayer ions held by ionic bonds in the aluminosilicate, which are more liable to dissolution. However, the Fe in NAu-2 was more likely to be bound by strong covalent bonds in aluminosilicate mineral, which is less soluble. The much highly soluble Fe in ATD was not only linked to the dissolution of an appreciable fraction of Fe(II), but also could be attributed to the fact that the Fe bonds in the clay fraction of ATD were mainly present as ionic bonds. The TEM images showed that reacted clay particles displayed less aggregate particles, with nanoparticle aggregates and the Fe/S-rich tiny particles attached to the remains.