Mesoscopic Structures of Vermiculite and Weathered Biotite Clays in Suspension with and without Cesium Ions

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• 作者：Ryuhei Motokawa ; Hitoshi Endo ; Shingo Yokoyama ; Hiroki Ogawa ; Tohru Kobayashi ; Shinichi Suzuki ; Tsuyoshi Yaita
• 刊名：Langmuir
• 出版年：2014
• 出版时间：December 23, 2014
• 年：2014
• 卷：30
• 期：50
• 页码：15127-15134
• 全文大小：364K
• ISSN：1520-5827

文摘

The effect of cesium (Cs) adsorption on the mesoscopic structure of the clay minerals vermiculite and weathered biotite (WB) in suspensions was elucidated by small-angle X-ray scattering (SAXS). The clay minerals form multilayered structures, and the Cs cations (Cs⁺) are strongly adsorbed in the interlayer space of the soil clays, in particular vermiculite and WB. SAXS was used to monitor the relationship between Cs⁺ adsorption at the clay interlayers and the structural changes at length scales from 1 to 1000 脜. The variation in the distance between the neighboring clay sheets and the spatial arrangement of the clay sheets with and without Cs⁺ were clarified. Our quantitative analyses revealed that the number of stacked layers of pure vermiculite was decreased by Cs⁺ addition, whereas that of WB increased. Moreover, the average distance between the neighboring layers of vermiculite in suspension was larger than that of WB, which reflects the different conditions of Cs⁺ intercalation. These findings provide fundamental insights that are important for predicting the environmental fate of radioactive Cs in contaminated regions and for developing methods for extracting Cs from soil.