Phosphate controls uranium release from acidic waste-weathered Hanford sediments
Root, Robert A.
O’Day, Peggy A.
AffiliationDepartment of Environmental Science, University of Arizona
MetadataShow full item record
CitationVázquez-Ortega, A., Perdrial, N., Reinoso-Maset, E., Root, R. A., O’Day, P. A., & Chorover, J. (2021). Phosphate controls uranium release from acidic waste-weathered Hanford sediments. Journal of Hazardous Materials, 416.
JournalJournal of Hazardous Materials
RightsPublished by Elsevier B.V.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractMineral dissolution and secondary phase precipitation may control the fate of inorganic contaminants introduced to soils and sediments during liquid waste discharges. When the solutions are aggressive enough to induce transformation of native minerals, incorporated contaminants may be released during dissolution due to percolation of meteoric waters. This study evaluated the release of uranium (U) from Hanford sediments that had been previously reacted for 180 or 365 days with liquid waste solutions containing U with and without 3 mM dissolved phosphate at pH 2 and 3. Flow-through column experiments were conducted under continuous saturated flow with a simulated background porewater (BPW; pH ~7) for 22 d. Up to 5% of the total U was released from the sediments reacted under PO4-free conditions, attributable to the dissolution of becquerelite and boltwoodite formed during weathering. Contrastingly, negligible U was released from PO4-reacted sediments, where meta-ankoleite was identified as the main U-mineral phase. Linear combination fits of U LIII-edge EXAFS spectra of sediments before and after BPW leaching and thermodynamic calculations suggest that the formed becquerelite and meta-ankoleite transformed into schoepite and a phosphuranylite-type phase, respectively. These results demonstrate the stabilization of U as recalcitrant uranyl minerals formed in sediments and highlight the key role of PO4 in U release at contaminated sites.
Note24 month embargo; available online 27 May 2021
VersionFinal accepted manuscript
SponsorsU.S. Department of Energy