Phosphate controls uranium release from acidic waste-weathered Hanford sediments
| Autor: | Angélica Vázquez-Ortega, Estela Reinoso-Maset, Robert A. Root, Nicolas Perdrial, Peggy A. O'Day, Jon Chorover |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Geologic Sediments
Water Pollutants Radioactive Environmental Engineering Hanford Site Health Toxicology and Mutagenesis 0211 other engineering and technologies chemistry.chemical_element 02 engineering and technology Boltwoodite 010501 environmental sciences 01 natural sciences Phosphates chemistry.chemical_compound Environmental Chemistry Leaching (agriculture) Waste Management and Disposal Dissolution 0105 earth and related environmental sciences Minerals 021110 strategic defence & security studies Uranium Uranyl Phosphate Pollution chemistry Environmental chemistry Schoepite |
| Zdroj: | Journal of Hazardous Materials. 416:126240 |
| ISSN: | 0304-3894 |
| DOI: | 10.1016/j.jhazmat.2021.126240 |
| Popis: | Mineral 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. |
| Databáze: | OpenAIRE |
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