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Title: Effect of Natural Organic Matter on Plutonium Sorption to Goethite

For this research, the effect of citric acid (CA), desferrioxamine B (DFOB), fulvic acid (FA), and humic acid (HA) on plutonium (Pu) sorption to goethite was studied as a function of organic carbon concentration and pH using batch sorption experiments at 5 mg C·L –1 and 50 mg C·L –1 natural organic matter (NOM), 10 –9–10 –10 M 238Pu, and 0.1 g·L –1 goethite concentrations, at pH 3, 5, 7, and 9. Low sorption of ligands coupled with strong Pu complexation decreased Pu sorption at pH 5 and 7, relative to a ligand-free system. Conversely, CA, FA, and HA increased Pu sorption to goethite at pH 3, suggesting ternary complex formation or, in the case of humic acid, incorporation into HA aggregates. Mechanisms for ternary complex formation were characterized by Fourier transform infrared spectroscopy in the absence of Pu. CA and FA demonstrated clear surface interactions at pH 3, HA appeared unchanged suggesting HA aggregates had formed, and no DFOB interactions were observed. Plutonium sorption decreased in the presence of DFOB (relative to a ligand free system) at all pH values examined. Thus, DFOB does not appear to facilitate formation of ternary Pu-DFOB-goethite complexes. At pH 9, Pu sorption inmore » the presence of all NOM increased relative to pH 5 and 7; speciation models attributed this to Pu(IV) hydrolysis competing with ligand complexation, increasing sorption. In conclusion, the results indicate that in simple Pu-NOM-goethite ternary batch systems, NOM will decrease Pu sorption to goethite at all but particularly low pH conditions.« less
Authors:
 [1] ;  [2] ;  [2] ; ORCiD logo [3]
  1. Clemson Univ., SC (United States). Department of Environmental Engineering and Earth Sciences
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Institute, Physical and Life Sciences Directorate
  3. Clemson Univ., SC (United States). Department of Environmental Engineering and Earth Sciences
Publication Date:
Report Number(s):
LLNL-JRNL-734915
Journal ID: ISSN 0013-936X
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Journal Volume: 51; Journal Issue: 1; Journal ID: ISSN 0013-936X
Publisher:
American Chemical Society (ACS)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
OSTI Identifier:
1409924