Characterization and acid-mobilization study for typical iron- bearing clay mineral  

作　　者：Zhenzhen Wang Rui Li Lulu Cui Hongbo Fu Jun Lin Jianmin Chen 

机构地区：[1]Shanghai Key Laboratory Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering,Fudan University, Shanghai 200433, China [2]Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science and Technology, Nanjing 210044, China [3]Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China [4]Key Laboratory of Nuclear Analysis Techniques, Shanghai Institute of Applied Physics, Chinese Academy of Sciences,Shanghai 201800, China

出　　处：《Journal of Environmental Sciences》2018年第9期222-232,共11页环境科学学报（英文版）

基　　金：provided by Ministry of Science and Technology of the People's Republic of China(2016YFC0202700);Ministry of Science and Technology of the People's Republic of China(2016YFE0112200);Ministry of Science and Technology of the People's Republic of China(2016YFC0203700);National Natural Science Foundation of China(Nos.21577022,21190053,and 40975074);International Cooperation Project of Shanghai Municipal Government(15520711200);Marie Sk?odowska-Curie Actions(690958-MARSU-RISE-2015)

摘　　要：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 M6ssbauer 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.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 M6ssbauer 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.

关 键 词：Clay particles DUST Iron mobilization Marine primary productivity 

分 类 号：X513[环境科学与工程—环境工程]