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This content will become publicly available on July 13, 2019

Title: Complexity of Uranyl Peroxide Cluster Speciation from Alkali-Directed Oxidative Dissolution of Uranium Dioxide

Solid UO 2 dissolution and uranium speciation in aqueous solutions that promote formation of uranyl peroxide macroanions was examined, focusing on the role of alkali metals. UO 2 powders were dissolved in solutions containing XOH (X = Li, Na, or K) and 30% H 2O2. Inductively coupled plasma optical emission spectroscopy (ICP-OES) measurements of solutions revealed linear trends of uranium versus alkali concentration in solutions resulting from oxidative dissolution of UO 2, with X:U molar ratios of 1.0, showing that alkali availability determines the U concentrations in solution. The maximum U concentration in solution was 4.36 x 10 5 parts per million (ppm), which is comparable to concentrations attained by dissolving UO 2 in boiling nitric acid, and was achieved by lithium hydroxide-promoted dissolution. Lastly, Raman spectroscopy and electrospray ionization mass spectrometry (ESI-MS) of solutions indicate that dissolution is accompanied by formation of various uranyl peroxide cluster species, the identity of which is alkali concentration-dependent, revealing remarkably complex speciation at high concentrations of base.
Authors:
 [1] ; ORCiD logo [1] ;  [2] ;  [1] ;  [2] ;  [1] ; ORCiD logo [3]
  1. Univ. of Notre Dame, IN (United States). Dept. of Civil and Environmental Engineering and Earth Sciences
  2. Univ. of Notre Dame, IN (United States). Dept. of Chemistry and Biochemistry
  3. Univ. of Notre Dame, IN (United States). Dept. of Civil and Environmental Engineering and Earth Sciences, and Dept. of Chemistry and Biochemistry
Publication Date:
Grant/Contract Number:
NA0003763; SC0001089
Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 57; Journal Issue: 15; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Research Org:
Univ. of Notre Dame, IN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; 36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; uranyl; peroxide; clusters; uranium dioxide
OSTI Identifier:
1460947