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Binding Environment of Strontium-87 Nuclei
in DOE Waste Remediation Materials


EMSL Project ID
17694

Abstract

In previous research with model inorganic systems, we found that DFS-QCPMG NMR on the 21.14 T spectrometer at PNNL provided significant sensitivity enhancements, permitting studies of 87Sr nuclei bound in phyllosilicate minerals. DFS-QCPMG at this field yields 100,000 fold reductions in acquisition time compared to static echo experiments on a more conventional 11.74 T spectrometer. We also found that the 87Sr quadrupolar parameters are highly sensitive to the local strontium coordination sphere and binding mechanism, demonstrating that 87Sr NMR is an effective method for exploring strontium binding in complex materials. Preliminary investigations in our most recent visit to PNNL demonstrated that the DFS-QCPMG technique at 21.14 T can also be used to study strontium sequestration by titania and titanosilicate minerals designed specifically to sorb strontium from tank waste solution. In this proposal, we intend to investigate the sequestration of strontium by additional titanosilicate minerals with tunable selectivity for strontium and cesium. Through our established NMR and analysis methods, we will gain insight into the strontium binding structure in these sorbant materials and determine the strength of the strontium/titanosilicate interactions. The results of our investigations will help to determine the appropriate course of action regarding the use of these materials at Hanford and Savannah River, as well as improve our understanding of strontium sequestration in complex materials. This research will be incorporated into a peer-reviewed publication.

Project Details

Project type
Capability Research
Start Date
2006-05-01
End Date
2007-05-21
Status
Closed

Team

Principal Investigator

Karl Mueller
Institution
Pacific Northwest National Laboratory

Team Members

Caleb Strepka
Institution
Pennsylvania State University

Michael Davis
Institution
Pennsylvania State University

Geoffrey Bowers
Institution
St. Mary's College of Maryland