Full metadata
Title
The versatile roles of sulfate-reducing bacteria for uranium bioremediation
Description
Uranium (U) contamination has been attracting public concern, and many researchers are investigating principles and applications of U remediation. The overall goal of my research is to understand the versatile roles of sulfate-reducing bacteria (SRB) in uranium bioremediation, including direct involvement (reducing U) and indirect involvement (protecting U reoxidation). I pursue this goal by studying Desulfovibro vuglaris, a representative SRB. For direct involvement, I performed experiments on uranium bioreduction and uraninite (UO2) production in batch tests and in a H2-based membrane biofilm reactor (MBfR) inoculated with D. vuglaris. In summary, D. vuglaris was able to immobilize soluble U(VI) by enzymatically reducing it to insoluble U(IV), and the nanocrystallinte UO2 was associated with the biomass. In the MBfR system, although D. vuglaris failed to form a biofilm, other microbial groups capable of U(VI) reduction formed a biofilm, and up to 95% U removal was achieved during a long-term operation. For the indirect involvement, I studied the production and characterization of and biogenic iron sulfide (FeS) in batch tests. In summary, D. vuglaris produced nanocrystalline FeS, a potential redox buffer to protect UO2 from remobilization by O2. My results demonstrate that a variety of controllable environmental parameters, including pH, free sulfide, and types of Fe sources and electron donors, significantly determined the characteristics of both biogenic solids, and those characteristics should affect U-sequestrating performance by SRB. Overall, my results provide a baseline for exploiting effective and sustainable approaches to U bioremediation, including the application of the novel MBfR technology to U sequestration from groundwater and biogenic FeS for protecting remobilization of sequestrated U, as well as the microbe-relevant tools to optimize U sequestration applicable in reality.
Date Created
2014
Contributors
- Zhou, Chen (Author)
- Rittmann, Bruce E. (Thesis advisor)
- Krajmalnik-Brown, Rosa (Committee member)
- Torres, César I (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
xiii, 146 p. : ill. (some col.)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.24928
Statement of Responsibility
by Chen Zhou
Description Source
Viewed on June 27, 2014
Level of coding
full
Note
thesis
Partial requirement for: Ph. D., Arizona State University, 2014
bibliography
Includes bibliographical references (p. 117-146)
Field of study: Civil and environmental engineering
System Created
- 2014-06-09 02:10:00
System Modified
- 2021-08-30 01:35:15
- 3 years 2 months ago
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