Cesium adsorption/desorption behavior of clay minerals considering actual contamination conditions in Fukushima

向井 広樹*; 廣瀬 農*; 甕 聡子*; 菊池 亮佑*; 田野井 慶太朗*; 中西 友子*; 矢板 毅; 小暮 敏博*

Scientific Reports (Internet), 6, p.21543_1 - 21543_7, 2016/02

https://doi.org/10.1038/srep21543

Cesium adsorption/desorption experiments for various clay minerals, considering actual contamination conditions in Fukushima, were conducted using the Cs radioisotope and an autoradiography using imaging plates (IPs). An aliquot containing 0.185 -1.85 Bq of Cs was dropped onto a substrate where various mineral particles were arranged. It was found that partially-vermiculitized biotite, which is termed "weathered biotite" (WB) in this study, from Fukushima sorbed Cs far more than the other clay minerals (fresh biotite, illite, smectite, kaolinite, halloysite, allophane, imogolite) on the same substrate. Cs-sorption to WB continued for about one day, whereas that to ferruginous smectite was completed within one hour. The sorbed Cs in WB was hardly leached with hydrochloric acid at pH 1, particularly in samples with a longer sorption time. The presence/absence of WB sorbing radiocesium is a key factor affecting the dynamics and fate of radiocesium in Fukushima.