Interactions of Ionic Liquids with Uranium and Its Bioreduction
We investigated the influence of ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]+[PF6]–, N-ethylpyridinium trifluoroacetate [EtPy]+[CF3COO]– and N-ethylpyridinium tetrafluoroborate [EtPy]+[BF4]– on uranium reduction by Clostridium sp. under anaerobic conditions. Potentiometric titration, UV-vis spectrophotometry, LC-MS and EXAFS analyses showed monodentate complexation between uranyl and BF4– PF6–; and bidentate complexation with CF3COO–. Ionic liquids affected the growth of Clostridium sp. as evidenced by decrease in optical density, changes in pH, gas production, and the extent of U(VI) reduction and precipitation of U(IV) from solution. Reduction of U(VI) to U(IV) was observed in the presence of [EtPy][BF4] and [BMIM][PF6] but not with [EtPy][CF3COO].
KeywordsIonic Liquid Uranyl Nitrate Absorption Edge Energy Bidentate Complex Uranium Reduction
- Anastas, P.T.; Warner, J.C. Green-Chemistry-Theory and Practice; Oxford University Press: New York, 1998.Google Scholar