Open AccessMesoscopic Structures of Vermiculite and Weathered Biotite Clays in Suspension with and without Cesium Ions
Author(s) -
Ryuhei Motokawa,
Hitoshi Endo,
Shiyoshi Yokoyama,
Hiroki Ogawa,
Tooru Kobayashi,
Shinichi Suzuki,
Tsuyoshi Yaita
Publication year - 2014
Publication title -
langmuir
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.042
H-Index - 333
eISSN - 1520-5827
pISSN - 0743-7463
DOI - 10.1021/la503992p
Subject(s) - vermiculite , biotite , clay minerals , suspension (topology) , small angle x ray scattering , caesium , adsorption , mesoscopic physics , mineralogy , chemistry , montmorillonite , intercalation (chemistry) , chemical engineering , inorganic chemistry , materials science , scattering , quartz , metallurgy , composite material , organic chemistry , mathematics , physics , quantum mechanics , homotopy , pure mathematics , optics , engineering
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 Å. 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.