The behaviors of various desorption agents were investigated during the desorption of cesium (Cs) from samples of clay minerals and actual soil. Results showed that polymeric cation exchange agents (polyethyleneimine (PEI)) efficiently desorbed Cs from expandable montmorillonite, whereas acidic desorption solutions containing HCl or PEI removed considerable Cs from hydrobiotite. However, most desorption agents could desorb only 54% of Cs from illite because of Cs’s specific adsorption to selective adsorption sites. Cs desorption from an actual soil sample containing Cs-selective clay mineral illite (< 200 μm) and extracted from near South Korea’s Kori Nuclear Power Plant was also investigated. Considerable adsorbed 137Cs was expected to be located at Cs-selective sites when the 137Cs loading was much lower than the sample’s cation exchange capacity. At this low 137Cs loading, the total Cs amount desorbed by repeated washing varied by desorption agent in the order HCl > PEI > NH4+, and the highest Cs desorption amount achieved using HCl was 83%. Unlike other desorption agents with only cation exchange capabilities, HCl can attack minerals and induce dissolution of metallic elements. HCl’s ability to both alter minerals and induce H+/Cs+ ion exchange is expected to promote Cs desorption from actual soil samples.

1. Introduction
2. Experimental
    2.1 Materials
    2.2 Sampling and fractionation of soil
    2.3 Characterization of clay minerals and soilsamples
    2.4 Preparation of Cs-adsorbed clay mineralsand soil samples
    2.5 Desorption of Cs from clay minerals andsoil samples
    2.6 Adsorption and desorption of radiocesium
3. Results and discussion
    3.1 Characterization of clay minerals and soilsamples
    3.2 Desorption of Cs from clay minerals andsoil sample
    3.3 Desorption of 137Cs from the soil samples
4. Conclusions
REFERENCES

• Chan Woo Park(Korea Atomic Energy Research Institute) Corresponding Author
• Ilgook Kim(Korea Atomic Energy Research Institute)
• In-Ho Yoon(Korea Atomic Energy Research Institute)
• Hee-Man Yang(Korea Atomic Energy Research Institute)
• Bum-Kyung Seo(Korea Atomic Energy Research Institute)