Anion-exchanged and quaternary ammonium functionalized MIL-101-Cr metal-organic framework (MOF) for ReO4-/TcO4- sequestration from groundwater

Dien Li; Natalia B Shustova; Corey R Martin; Kathryn Taylor-Pashow; John C Seaman; Daniel I Kaplan; Jake W Amoroso; Roman Chernikov

doi:10.1016/j.jenvrad.2020.106372

Anion-exchanged and quaternary ammonium functionalized MIL-101-Cr metal-organic framework (MOF) for ReO₄^-/TcO₄^- sequestration from groundwater

J Environ Radioact. 2020 Oct:222:106372. doi: 10.1016/j.jenvrad.2020.106372. Epub 2020 Aug 6.

Authors

Dien Li¹, Natalia B Shustova², Corey R Martin², Kathryn Taylor-Pashow³, John C Seaman⁴, Daniel I Kaplan³, Jake W Amoroso³, Roman Chernikov⁵

Affiliations

¹ Savannah River National Laboratory, Aiken, SC, 29808, USA. Electronic address: Dien.Li@srs.gov.
² Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA.
³ Savannah River National Laboratory, Aiken, SC, 29808, USA.
⁴ Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA.
⁵ Canadian Light Source, Saskatoon, SK, S7N 0X4, Canada.

PMID: 32771856
DOI: 10.1016/j.jenvrad.2020.106372

Abstract

There are few effective technologies for the sequestration of highly water-soluble pertechnetate (TcO₄^-) from contaminated water despite the urgency of environmental and public health concerns. In this work, anion exchanged and cetyltrimethylammonium bromide (CTAB) functionalized MIL-101-Cr-NO₃ were investigated for perrhenate (ReO₄^-), a surrogate of TcO₄^-, sequestration from artificial groundwater. Cl^-, I^-, and CF₃SO₃^- exchanged MIL-101-Cr proved more effective at ReO₄^- removal than the parent MIL-101-Cr-F. Compared to the parent framework, CTAB functionalized MIL-101-Cr-NO₃ increased ReO₄^- removal capacity from 39 to 139 mg/g, improved the reaction kinetics from ~30 to <10 min to reach full adsorption capacity and the selectivity for ReO₄^- over competing NO₃^-, CO₃^2-, SO₄^2-, and Cl^-. Spectroscopic data indicated that the chemical speciation of Re in the exchanged MIL-101-Cr remained ReO₄^-, indicating synergistic sequestration through both anion exchange and non-ion exchange binding with the positively charged ligand of CTAB. These studies foreshadow potential applications of MOFs for the remediation of ⁹⁹TcO₄^- from contaminated environments.

Keywords: CTAB functionalization; MIL-101-Cr; Perrhenate; Pertechnetate; Sequestration.

Published by Elsevier Ltd.

MeSH terms

Ammonium Compounds*
Anions
Groundwater*
Metal-Organic Frameworks*
Radiation Monitoring*

Substances

Ammonium Compounds
Anions
MIL-101
Metal-Organic Frameworks