EFFECTS OF pH, TEMPERATURE AND AQUEOUS ORGANIC MATERIAL ON THE RELEASE URANIUM FROM URANYL-PHOSPHATE MINERALS
Single-pass flow-through (SPFT) tests were conducted to study the effects of aqueous organic material on the dissolution kinetics of synthetic sodium meta-autunite, Na{sub 2}[(UO{sub 2}){sub 2}(PO{sub 4}){sub 2}] 3H{sub 2}O, as a function of pH ( 7 -10) and temperature (25 ? 70 C). System conditions were identical except for the chemical composition of the buffer which consisted of either the organic 0.05 M tris(hydroxymethyl)aminomethane (TRIS) buffer, or the inorganic 0.1M ammonium hydroxide (NH{sub 4}OH) buffer solution. Both systems exhibited an increase in the release rates of uranium with increasing pH and temperature. However, the release of uranium was 10-1000X greater in the presence of aqueous organic material. Additionally, saturation limits for secondary uranyl-phases were typically met under inorganic conditions, but rarely achieved within the organic environment. The results highlight the importance of aqueous organic material and secondary uranyl-phases on the long-term fate of uranium in the environment.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 15020746
- Report Number(s):
- PNNL-SA-41674; KP1301020; TRN: US0504657
- Resource Relation:
- Conference: 228th ACS National Meeting , 44(2):1139-1146; American Chemical Society, Division of Environmental Chemistry,Cape Girardeau,,United States.
- Country of Publication:
- United States
- Language:
- English
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