Sodium meta-autunite colloids: Synthesis, characterization,stability
Waste forms of U such as those in the United States Department of Energy's Hanford Site often contain high concentrations of Na and P. Low solubility sodium uranyl phosphates such as sodium meta-autunite have the potential to form mobile colloids that can facilitate transport of this radionuclide. In order to understand the geochemical behavior of uranyl phosphate colloids, we synthesized sodiummeta-autunite colloids, and characterized their morphology, chemical composition, structure, dehydration, and surface charge. The stability of these synthetic plate-shaped colloids was tested with respect to time and pH. The highest aggregation rate was observed at pH 3, and the rate decreases as pH increases, indicating that higher stability of colloid dispersion under neutral and alkaline pH conditions. The synthetic colloids are all negatively charged and no isoelectric points were found over a pH range of 3 to 9. The zeta-potentials of the colloids in the phosphate solution show a strong pH-dependence in the more acidic range over time, but are relatively constant in the neutral and alkaline pH range. The geochemical behavior of the synthetic colloids can be interpreted using DLVO theory. The results suggest that formation of mobile sodium meta-autunite colloids can enhance the transport of U in some contaminated sediments.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Basic EnergySciences
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 886763
- Report Number(s):
- LBNL--54563; BnR: KP1301010
- Journal Information:
- Colloids and Surfaces. A, Physicochemical and Engineering Aspects, Journal Name: Colloids and Surfaces. A, Physicochemical and Engineering Aspects Journal Issue: 1-3 Vol. 274; ISSN 0927-7757
- Country of Publication:
- United States
- Language:
- English
Similar Records
Meta-Autunite Solubility as Related to Uranium Minerals in Concrete Waste Forms
Meta-Autunite Solubility as Related to Uranium Minerals in Concrete Waste Forms
Related Subjects
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
CHEMICAL COMPOSITION
COLLOIDS
DEHYDRATION
MORPHOLOGY
PHOSPHATES
SEDIMENTS
SODIUM
SOLUBILITY
STABILITY
SYNTHESIS
TRANSPORT
URANYL PHOSPHATES
Uranium Sodium Meta-Autunite Colloids Zeta PotentialTransport
WASTE FORMS