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Title: Dynamic interplay between uranyl phosphate precipitation, sorption, and phase evolution

We report that natural examples demonstrate uranyl-phosphate minerals can maintain extremely low levels of aqueous uranium in groundwaters due to their low solubility. Thus, greater understanding of the geochemical factors leading to uranyl phosphate precipitation may lead to successful application of phosphate-based remediation methods. However, the solubility of uranyl phosphate phases varies over >3 orders of magnitude, with the most soluble phases typically observed in lab experiments. To understand the role of common soil/sediment mineral surfaces in the nucleation and transformation of uranyl phosphate minerals under environmentally relevant conditions, we carried out batch experiments with goethite and mica at pH 6 in mixed electrolyte solutions ranging from 1–800 μM U and 1–800 μM P. All experiments ended with uranium concentrations below the USEPA MCL for U, but with 2–3 orders of magnitude difference in uranium concentrations.
Authors:
 [1] ;  [1] ;  [2] ;  [1]
  1. Univ. of Oklahoma, Norman, OK (United States). School of Geology and Geophysics
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division
Publication Date:
OSTI Identifier:
1265483
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Applied Geochemistry
Additional Journal Information:
Journal Volume: 58; Journal Issue: C; Journal ID: ISSN 0883-2927
Publisher:
Elsevier
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES