Caesium incorporation and retention in illite interlayers
Caesium incorporation and retention in illite interlayers
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DOI：
10.1016/j.clay.2015.02.008
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发表时间：
2015-05-01
影响因子：
5.6
通讯作者：
Burke, Ian T.
中科院分区：
文献类型：
--
作者：
Fuller, Adam J.;Shaw, Samuel;Burke, Ian T.
放射性铯（主要是Cs-137）是一种主要的环境污染物。Cs在温带土壤中的流动性主要受粘土矿物的吸附控制，特别是伊利石夹层的磨损边缘。本文在分子尺度上研究了铯在伊利石上的短期和长期吸附。透射电子显微镜（TEM）图像显示，在磨损的边缘，Cs迁移到伊利石夹层成为纳入矿物结构的初始吸收。铯最初与磨损边缘的水合Ca交换，导致它们坍塌。这一过程是不可逆的，因为塌陷夹层中的Cs不能与Ca交换。Cs不再停留在伊利石晶体的边缘，而是通过与K的交换扩散到层间。扩展X射线吸收精细结构谱（EXAFS）和密度泛函理论模拟的结果证实，铯被纳入伊利石夹层，并揭示其成键环境。(C)2015作者由爱思唯尔公司出版
Radioactive caesium (chiefly Cs-137) is a major environmental pollutant. The mobility of Cs in temperate soils is primarily controlled by sorption onto clay minerals, particularly the frayed edges of illite interlayers. This paper investigates the adsorption of Cs to illite at the molecular scale, over both the short and long term. Transmission electron microscopy (TEM) images showed that after initial absorption into the frayed edges, Cs migrated into the illite interlayer becoming incorporated within the mineral structure. Caesium initially exchanged with hydrated Ca at the frayed edges, causing them to collapse. This process was irreversible as Cs held in the collapsed interlayers was not exchangeable with Ca. Over the long term Cs did not remain at the edge of the illite crystals, but diffused into the interlayers by exchange with K. Results from extended X-ray absorption fine structure spectroscopy (EXAFS) and density functional theory modelling confirmed that Cs was incorporated into the illite interlayer and revealed its bonding environment. (C) 2015 The Authors. Published by Elsevier B.V.