Porous iron material for TcO_4⁻ and ReO_4⁻ sequestration from groundwater under ambient oxic conditions

Journal Article · 09 April 2019 · Journal of Hazardous Materials

DOI: https://doi.org/10.1016/j.jhazmat.2019.04.030 · OSTI ID:1525790

Li, Dien  ^[1]; Seaman, John C. ^[2]; Hunyadi Murph, Simona E. ^[3]; Kaplan, Daniel I. ^[1]; Taylor-Pashow, Kathryn  ^[1]; Feng, Renfei  ^[4]; Chang, Hyunshik ^[5]; Tandukar, Madan ^[5]

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1. Savannah River Site (SRS), Aiken, SC (United States)
2. Univ. of Georgia, Aiken, SC (United States)
3. Savannah River Site (SRS), Aiken, SC (United States); Univ. of Georgia, Athens, GA (United States)
4. Canadian Light Sources, Inc., Saskatoon, SK (Canada)
5. Hӧganäs Environmental Solutions LLC, Cary, NC (United States)

Technetium-99 (⁹⁹Tc) is a critical contaminant at nuclear power plants and several US Department of Energy sites. Its most common aqueous species, pertechnetate (TcO_4⁻), is very mobile in the environment, and currently there are no effective technologies for its sequestration. Here, a porous iron (pFe) material was investigated for TcO_4⁻ and perrhenate (ReO_4⁻) sequestration from artificial groundwater. The pFe was significantly more effective than granular iron for both TcO_4⁻ and ReO_4⁻ sequestration under oxic conditions. The Tc removal capacity was 27.5 mg Tc/g pFe at pH ⁻6.8, while the Re removal capacity was 23.9 mg Re/g pFe at pH ⁻10.6. Tc K-edge XANES and EXAFS analyses indicated that the removed Tc species was 70–80% Tc(IV) that was likely incorporated into Fe corrosion products (i.e., Fe(OOH), Fe₃O₄) and 20–30% unreduced TcO_4⁻. In contrast, the removed Re species was ReO_4⁻ only, without detectable Re(IV). In addition, the sequestered ReO_4⁻ was not extracted (<3%) by 0.1 M Na₂SO₄ and 1 M KI solution, which indicated that ReO_4⁻ and by chemical analogy, unreduced TcO_4⁻ was likely incorporated into Fe corrosion products. This inexpensive pFe material may be applied to the sequestration and stabilization of ⁹⁹TcO_4⁻ from contaminated environments and nuclear waste streams.

• Research Organization: Savannah River Site (SRS), Aiken, SC (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE
• Grant/Contract Number: AC09-08SR22470; AC09-96SR18500; FC09-07SR22506
• OSTI ID: 1525790
• Alternate ID(s): OSTI ID: 1636839
• Report Number(s): SRNL-STI-2018-00651
• Journal Information: Journal of Hazardous Materials, Vol. 374, Issue C; ISSN 0304-3894
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English