Ability of micaceous minerals to adsorb and desorb caesium ions: Effects of mineral type and degree of weathering

• Published in: European journal of soil science 2020-07, Vol.71 (4), p.641-653
• Main Authors: Kitayama, Rikuo, Yanai, Junta, Nakao, Atsushi
• Format: Article
• Language: English
• Subjects: 137Cs; Acetates; Acetic acid; Adsorption; Ammonium; Ammonium acetate; Ammonium compounds; Biotite; Caesium; Caesium 137; Cesium 137; Cesium ions; Cesium isotopes; Cesium radioisotopes; Depletion; Desorption; frayed edge site (FES); Illite; Illites; Interception; Interlayers; Ions; Localization; Mica; Minerals; Muscovite; Potassium; radiocaesium interception potential (RIP); Selective adsorption; Soil; Soil investigations; Soils; Vermiculite; Vermiculites; Weathering
• ISSN: 1351-0754; 1365-2389
• DOI: 10.1111/ejss.12913

To evaluate the effects of type of micaceous mineral and degree of weathering on the ability to adsorb and desorb radiocaesium (RCs) ions, various levels of weathering were induced (K‐depletion) in three types of micaceous minerals: biotite, muscovite and illite. The ability to adsorb RCs was represented by RCs interception potential (RIP) and a desorption ratio was determined by the amount of 137Cs desorbed from the minerals by 1 M ammonium acetate (137Cs desorption ratio). The RIP values were in the order of illite > biotite > muscovite. The RIP values for biotite gradually increased with the release of up to ~50% of the K+ from interlayer sites but then decreased with the further release of K+, up to ~100%, which was associated with the formation of a fully expanded interlayer: vermiculite. The change from increasing to decreasing RIP due to the weathering of the biotite strongly indicated that the selective adsorption sites for RCs are not located in an expanded interlayer but in intermediate sites between non‐expanded and expanded interlayers: frayed edge sites (FES). In contrast, for both the muscovite and illite, the RIP only increased. The 137Cs desorption ratio,