In situ spectroscopic evidence for neptunium(V)-carbonate inner-sphere and outer-sphere ternary surface complexes on hematite surfaces

Yuji Arai, P. B. Moran, B. D. Honeyman, J. A. Davis

Research output: Contribution to journalArticle

Abstract

Np(V) surface speciation on hematite surfaces at pH 7-9 under pCO 2 = 10-3.45 atm was investigated using X-ray absorption spectroscopy (XAS). In situ XAS analyses suggest that bis-carbonato inner-sphere and tris-carbonato outersphere ternary surface species coexist at the hematite-water interface at pH 7-8.8, and the fraction of outer-sphere species gradually increases from 27 to 54% with increasing pH from 7 to 8.8. The results suggest that the heretofore unknown Np(V)-carbonato ternary surface species may be important in predicting the fate and transport of Np(V) in the subsurface environment down gradient of high-level nuclear waste respositories.

Original languageEnglish (US)
Pages (from-to)3940-3944
Number of pages5
JournalEnvironmental Science and Technology
Volume41
Issue number11
DOIs
StatePublished - Jun 1 2007
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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