Enhanced desorption of Cs from clays by a polymeric cation-exchange agent

• Published in: Journal of hazardous materials Vol. 327; pp. 127 - 134
• Main Authors: Park, Chan Woo, Kim, Bo Hyun, Yang, Hee-Man, Seo, Bum-Kyoung, Lee, Kune-Woo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.04.2017
• Subjects: Cesium; Clay; Desorption; Polyelectrolyte; Polyethyleneimine; Polyelectrolyte; Polyethyleneimine; Clay; Cesium; Desorption
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2016.12.037

[Display omitted] •A cationic polyelectrolyte has excellent ability to desorb Cs bound strongly to clay.•The polycation desorbed significantly more Cs from the clay than did single cations.•Additional NH4+ treatment following the polycation treatment enhanced desorption of Cs.•The reaction yielded efficient desorption (95%) of an extremely low concentration of Cs-137 in the clay. We report on a new approach to increase the removal of cesium from contaminated clays based on the intercalation of a cationic polyelectrolyte into the clay interlayers. A highly charged cationic polyelectrolyte, polyethyleneimine (PEI), was shown to intercalate into the negatively charged interlayers and readily replaced Cs ions adsorbed on the interlayers of montmorillonite. The polycation desorbed significantly more Cs strongly bound to the clay than did single cations. Moreover, additional NH4+ treatment following the PEI treatment enhanced desorption of Cs ions that were less accessible by the bulky polyelectrolyte. This synergistic effect of PEI with NH4+ yielded efficient desorption (95%) of an extremely low concentration of radioactive 137Cs in the clay, which is very difficult to remove by simple cation-exchange methods due to the increased stability of the binding of Cs to the clay at low Cs concentrations.