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Title: Incorporation of oxidized uranium into Fe (hydr)oxides during Fe(II) catalyzed remineralization

Abstract

The form of solid phase U after Fe(II) induced anaerobic remineralization of ferrihydrite in the presence of aqueous and absorbed U(VI) was investigated under both abiotic batch and biotic flow conditions. Experiments were conducted with synthetic ground waters containing 0.168 mM U(VI), 3.8 mM carbonate, and 3.0 mM Ca{sup 2+}. In spite of the high solubility of U(VI) under these conditions, appreciable removal of U(VI) from solution was observed in both the abiotic and biotic systems. The majority of the removed U was determined to be substituted as oxidized U (U(VI) or U(V)) into the octahedral position of the goethite and magnetite formed during ferrihydrite remineralization. It is estimated that between 3% and 6% of octahedral Fe(III) centers in the new Fe minerals were occupied by U(VI). This site specific substitution is distinct from the non-specific U co-precipitation processes in which uranyl compounds, e.g. uranyl hydroxide or carbonate, are entrapped with newly formed Fe oxides. The prevalence of site specific U incorporation under both abiotic and biotic conditions and the fact that the produced solids were shown to be resistant to both extraction (30 mM KHCO{sub 3}) and oxidation (air for 5 days) suggest the potential importance of sequestration inmore » Fe oxides as a stable and immobile form of U in the environment.« less

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Earth Sciences Division
OSTI Identifier:
972812
Report Number(s):
LBNL-2506E
Journal ID: ISSN 0013-936X; ESTHAG; TRN: US201006%%234
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 43; Journal Issue: 19
Country of Publication:
United States
Language:
English
Subject:
54; 58; AIR; GOETHITE; GROUND WATER; HYDROXIDES; MAGNETITE; OXIDATION; OXIDES; REMOVAL; SOLUBILITY; URANIUM; URANYL COMPOUNDS

Citation Formats

Nico, Peter S., Stewart, Brandy D., and Fendorf, Scott. Incorporation of oxidized uranium into Fe (hydr)oxides during Fe(II) catalyzed remineralization. United States: N. p., 2009. Web. doi:10.1021/es900515q.
Nico, Peter S., Stewart, Brandy D., & Fendorf, Scott. Incorporation of oxidized uranium into Fe (hydr)oxides during Fe(II) catalyzed remineralization. United States. doi:10.1021/es900515q.
Nico, Peter S., Stewart, Brandy D., and Fendorf, Scott. Wed . "Incorporation of oxidized uranium into Fe (hydr)oxides during Fe(II) catalyzed remineralization". United States. doi:10.1021/es900515q. https://www.osti.gov/servlets/purl/972812.
@article{osti_972812,
title = {Incorporation of oxidized uranium into Fe (hydr)oxides during Fe(II) catalyzed remineralization},
author = {Nico, Peter S. and Stewart, Brandy D. and Fendorf, Scott},
abstractNote = {The form of solid phase U after Fe(II) induced anaerobic remineralization of ferrihydrite in the presence of aqueous and absorbed U(VI) was investigated under both abiotic batch and biotic flow conditions. Experiments were conducted with synthetic ground waters containing 0.168 mM U(VI), 3.8 mM carbonate, and 3.0 mM Ca{sup 2+}. In spite of the high solubility of U(VI) under these conditions, appreciable removal of U(VI) from solution was observed in both the abiotic and biotic systems. The majority of the removed U was determined to be substituted as oxidized U (U(VI) or U(V)) into the octahedral position of the goethite and magnetite formed during ferrihydrite remineralization. It is estimated that between 3% and 6% of octahedral Fe(III) centers in the new Fe minerals were occupied by U(VI). This site specific substitution is distinct from the non-specific U co-precipitation processes in which uranyl compounds, e.g. uranyl hydroxide or carbonate, are entrapped with newly formed Fe oxides. The prevalence of site specific U incorporation under both abiotic and biotic conditions and the fact that the produced solids were shown to be resistant to both extraction (30 mM KHCO{sub 3}) and oxidation (air for 5 days) suggest the potential importance of sequestration in Fe oxides as a stable and immobile form of U in the environment.},
doi = {10.1021/es900515q},
journal = {Environmental Science and Technology},
number = 19,
volume = 43,
place = {United States},
year = {Wed Jul 01 00:00:00 EDT 2009},
month = {Wed Jul 01 00:00:00 EDT 2009}
}