Kinetic analysis and modeling of oleate and ethanol stimulated uranium (VI) bio-reduction in contaminated sediments under sulfate reduction conditions.
Microcosm tests with uranium contaminated sediments were performed to explore the feasibility of using oleate as a slow-release electron donor for U(VI) reduction in comparison to ethanol. Oleate degradation proceeded more slowly than ethanol with acetate produced as an intermediate for both electron donors under a range of initial sulfate concentrations. A kinetic microbial reduction model was developed and implemented to describe and compare the reduction of sulfate and U(VI) with oleate or ethanol. The reaction path model considers detailed oleate/ethanol degradation and the production and consumption of intermediates, acetate and hydrogen. Although significant assumptions are made, the model tracked the major trend of sulfate and U(VI) reduction and describes the successive production and consumption of acetate, concurrent with microbial reduction of aqueous sulfate and U(VI) species. The model results imply that the overall rate of U(VI) bioreduction is influenced by both the degradation rate of organic substrates and consumption rate of intermediate products.
Zhang
Fan
F
Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China. zhangfan@itpcas.ac.cn
Wu
Wei-Min
WM
Parker
Jack C
JC
Mehlhorn
Tonia
T
Kelly
Shelly D
SD
Kemner
Kenneth M
KM
Zhang
Gengxin
G
Schadt
Christopher
C
Brooks
Scott C
SC
Criddle
Craig S
CS
Watson
David B
DB
Jardine
Philip M
PM
D001673:Biodegradation, Environmental; D003666:Decontamination / Q000379:methods*; D000431:Ethanol / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D019301:Oleic Acid / Q000737:chemistry*; D019163:Reducing Agents / Q000737:chemistry; D013431:Sulfates; D014501:Uranium / Q000737:chemistry*
D019163:Reducing Agents; D013431:Sulfates; D019301:Oleic Acid; D000431:Ethanol; D014501:Uranium