Graduate School of Environmental Science, Hokkaido University, Kita 10 Nishi 5, Kita-ku, Sapporo, 060-0810, Japan.
Research Institute of Energy, Environment and Geology, Industrial Technology and Environment Research Department, Hokkaido Research Organization, Kita 19 Nishi 11, Kita-ku, Sapporo, 060-0819, Japan.
Environ Sci Pollut Res Int. 2021 Mar;28(11):14121-14130. doi: 10.1007/s11356-020-11476-7. Epub 2020 Nov 18.
Cesium (Cs) is known to have a strong interaction with various clay minerals; however, it is not interpreted from the structure of clay minerals and the adsorption isotherm. The adsorption interactions between Cs and hydrobiotite (H-Bio), biotite (Bio), vermiculite (Verm), and exfoliated vermiculite (E-Verm) were evaluated by analyzing adsorption isotherm, basal spacing, and adsorption/desorption experiments. The Cs adsorption of H-Bio and Verm fitted well to the Langmuir adsorption isotherm, while the Cs adsorption of Bio and E-Verm fitted well to the Freundlich adsorption isotherm. The basal spacing of H-Bio and Verm was approximately 1.4 nm, while Bio and E-Verm basal spacing was 1.0 nm. The adsorption experiment results for Cs under the coexistence of Ca and K indicated that the contribution of the interlayer sites to Cs adsorption on H-Bio and Verm was 25-40%, while the contribution of the interlayer sites to that on Bio and E-Verm was almost 0%. The adsorption isotherms reflected this interlayer contribution to Cs adsorption, which was dependent on the basal spacing. Therefore, the basal spacing of clay minerals is one of the key structural properties controlling both the adsorption capacity and the adsorption mechanism of Cs in clay minerals.
铯（Cs）与各种粘土矿物具有很强的相互作用，但从粘土矿物的结构和吸附等温线来看，这种相互作用并没有得到解释。通过分析吸附等温线、基面间距和吸附/解吸实验，评估了 Cs 与氢云母（H-Bio）、云母（Bio）、蛭石（Verm）和膨胀蛭石（E-Verm）之间的吸附相互作用。H-Bio 和 Verm 的 Cs 吸附符合 Langmuir 吸附等温线，而 Bio 和 E-Verm 的 Cs 吸附符合 Freundlich 吸附等温线。H-Bio 和 Verm 的基面间距约为 1.4nm，而 Bio 和 E-Verm 的基面间距为 1.0nm。在 Ca 和 K 共存下进行的 Cs 吸附实验结果表明，层间位点对 H-Bio 和 Verm 上 Cs 吸附的贡献为 25-40%，而层间位点对 Bio 和 E-Verm 上 Cs 吸附的贡献几乎为 0%。吸附等温线反映了这种层间贡献对 Cs 吸附的影响，这取决于基面间距。因此，粘土矿物的基面间距是控制粘土矿物中 Cs 吸附容量和吸附机制的关键结构特性之一。
