Evaluation of sorption behavior of iodide ions on calcium sificate hydrate and hydrotalcite

Taiji Chida, Jun Furuya, Yuichi Niibori, Hitoshi Mimura

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The migration retardation of anionic radionuclides, notably 1-129, in radioactive waste repositories is one of the most critical factors for improving the performance of engineered barriers. To gain more fundamental knowledge required to make such improvements, this study examined the sorption behavior of iodide ions on calcium silicate hydrate (CSH) and hydrotalcite (HT), which act as anion exchangers. CSH was synthesized using CaO and fumed silica, with Ca/Si molar ratios ranging from 0.4 to 1.6. The weight ratio of CSH to HT was 1.0. These solid samples were immersed for 14 days in a 30 mL sample of pure water or 0.6 M NaCI solution, each of which contained 0.5 mM iodide ions with a given liquid/solid weight ratio (10, 15, or 20). Raman spectroscopy studies indicated that the structures of CSH and HT were maintained during the hydration of the solid phase and the sorption of iodide ions. The distribution coefficients for the sorption of iodide ions on CSH and HT ranged from 6 to 13 L/kg for pure water and from 1 to 2 LIkg for NaCl solution. These retardation effects for iodide ions would contribute toward improving the performance of the repository system as most conventional safety assessments assume that iodide ions hardly sorb on engineered barriers such as cementitious materials.

Original languageEnglish
Title of host publicationScientific Basis for Nuclear Waste Management XXXVIII
EditorsStephane Gin, Robert Jubin, Eric Vance, Josef Matyas
PublisherMaterials Research Society
Pages29-34
Number of pages6
ISBN (Electronic)9781605117218
DOIs
Publication statusPublished - 2015 Jan 1
Event2014 MRS Fall Meeting - Boston, United States
Duration: 2014 Nov 302014 Dec 5

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1744
ISSN (Print)0272-9172

Other

Other2014 MRS Fall Meeting
CountryUnited States
CityBoston
Period14/11/3014/12/5

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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