Impeding 99Tc(IV) mobility in novel waste forms

Mal Soon Lee, Wooyong Um, Guohui Wang, Albert A. Kruger, Wayne W. Lukens, Roger Rousseau, Vassiliki Alexandra Glezakou

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Abstract

Technetium (99Tc) is an abundant, long-lived radioactive fission product whose mobility in the subsurface is largely governed by its oxidation state. Tc immobilization is crucial for radioactive waste management and environmental remediation. Tc(IV) incorporation in spinels has been proposed as a novel method to increase Tc retention in glass waste forms during vitrification. However, experiments under high-temperature and oxic conditions show reoxidation of Tc(IV) to volatile pertechnetate, Tc(VII). Here we examine this problem with ab initio molecular dynamics simulations and propose that, at elevated temperatures, doping with first row transition metal can significantly enhance Tc retention in magnetite in the order Co>Zn>Ni. Experiments with doped spinels at 700 °C provide quantitative confirmation of the theoretical predictions in the same order. This work highlights the power of modern, state-of-the-art simulations to provide essential insights and generate theory-inspired design criteria of complex materials at elevated temperatures.

Original languageEnglish
Article number12067
JournalNature communications
Volume7
DOIs
Publication statusPublished - Jun 30 2016

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ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

Cite this

Lee, M. S., Um, W., Wang, G., Kruger, A. A., Lukens, W. W., Rousseau, R., & Glezakou, V. A. (2016). Impeding 99Tc(IV) mobility in novel waste forms. Nature communications, 7, [12067]. https://doi.org/10.1038/ncomms12067