Enhanced irreversible fixation of cesium by wetting and drying cycles in soil

Sang Min Park, Jung Seok Yang, Daniel C.W. Tsang, Daniel S. Alessi, Kitae Baek

Research output: Journal article publicationJournal articleAcademic researchpeer-review

12 Citations (Scopus)

Abstract

The retention of radioactive cesium (Cs) in soil is significantly related to the types of clay minerals, while the weathering process affects the irreversible adsorption sites in clay minerals. In this study, the effect of weathering (exposure duration of Cs and repeated wetting and drying cycles) on fractionation of Cs in soils was investigated using fractionation analysis by the sequential extraction. The residual fraction of Cs increased slowly with exposure time but increased rapidly by repeated wetting and drying cycles. XRD analysis shows that a 1.43 nm of interlayer size for vermiculite is shortened to 1.00 nm, i.e., similar to that of illite. The change implies the potential that the structure of expandable clay minerals is transformed to the non-expandable structure by weathering process after Cs retention. Based on the result, the residual fraction of Cs, most stable form of Cs in the soil, reached relatively rapidly to a maximum. However, the process is much slower kinetically in the field because the bench-scale weathering process used in this study is more aggressive. This study implies that Cs fractionations in the soil are converted into a more stable fraction by weathering processes in the soil. Therefore, Cs removal should be conducted as soon as possible after accidental release of Cs in an environmental side.

Original languageEnglish
Pages (from-to)149-157
Number of pages9
JournalEnvironmental Geochemistry and Health
Volume41
Issue number1
DOIs
Publication statusPublished - 15 Feb 2019

Keywords

  • Cesium fractionation
  • Clay minerals
  • Soil contamination
  • Weathering
  • Wetting and drying cycles

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Water Science and Technology
  • Environmental Science(all)
  • Geochemistry and Petrology

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