SREL Reprint #3596

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

Dien Li1, Natalia B. Shustova2, Corey R. Martin2, Kathryn Taylor-Pashow1, John C. Seaman3,
Daniel I. Kaplan1, Jake W. Amoroso1, and Roman Chernikov4

1Savannah River National Laboratory, Aiken, SC, 29808, USA
2Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, 29208, USA
3Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, 29802, USA
4Canadian Light Source, Saskatoon, SK, S7N 0X4, Canada

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–, CO32–, SO42–, 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: Pertechnetate; Perrhenate; CTAB functionalization; MIL-101-Cr; Sequestration

SREL Reprint #3596

Li, D., N. B. Shustova, C. R. Martin, K. Taylor-Pashow, J. C. Seaman, D. I. Kaplan, J. W. Amoroso, and R. Chernikov. 2020. Anion-exchanged and quaternary ammonium functionalized MIL-101-Cr metal-organic framework (MOF) for ReO4–/TcO4– sequestration from groundwater. Journal of Environmental Radioactivity 222(2020): 106372.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).