Uranium Immobilization by Sulfate-Reducing Biofilms
EMSL Project ID
6513
Abstract
In our previous study (Beyenal et al., 2003) we have investigated uranium immobilization by sulfate reducing biofilms and found that sulfate reducing biofilms can successfully immobilize uranium for significant amount of time. In continuation to the project, currently, we are operating 3 column reactors filled with hematite, dolomite and calcite (as support material for biofilm growth) and flat plate flow reactors with glass substratum inoculated with sulfate reducing bacteria. The bacteria grew as biofilms in all reactors and successfully immobilized uranium which was quantified from the concentration measurements at the inlet and outlet of the reactors. Uranium can be immobilized 1) by binding to EPS (biosorption), 2) enzymatic reduction, 3) chemical reduction by sulfide (Beyenal et al., 2003). Our current facilities do not allow us to quantify the chemistry of uranium immobilized on biofilm surfaces. We believe characterization of uranium on biofilms will help us understand efficiency of sulfate reducing biofilms for uranium reduction. In addition, in our previous work (Beyenal et al., 2003), we found that sulfide chemically reduce uranium and produce uraninite as black precipitates. We observed the same black precipitates on biofilm surfaces and suspicious that they are uraninite. These observations require to be investigated using advance techniques. We are planning to use TEM to locate uranium by X-ray emission, identify the morphology of the U containing particles, and then use electron diffraction to determine their crystalline structures. We will prepare samples according to given procedures by EMSL staff and ship the samples following safety procedures. After the measurements performed if necessary we will take samples back and dispose accordingly.
We are expecting to prepare a manuscript from the uranium characterization measurements as a joint publication with EMSL staff.
Reference
Beyenal, H., Sani, R. K., Peyton, B. M., Dohnalkova, A., Amonette, J. E., Lewandowski, Z. Uranium immobilization by sulfate reducing biofilms. Environmental Science and Technology (accepted with revision).
Project Details
Project type
Exploratory Research
Start Date
2004-01-22
End Date
2006-11-02
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
JE Amonette, Z Lewandowski, A Dohnalkova, Beyenal H, RK Sani, and BM Peyton. 2004. "Uranium Immobilization by Sulfate-reducing Biofilms." Environmental Science and Technology 38(7):2067-2074.