Details

Autor(en) / Beteiligte

• Cutting, Richard S
• Coker, Victoria S
• Telling, Neil D
• Kimber, Richard L
• Pearce, Carolyn I
• Ellis, Beverly L
• Lawson, Richard S
• van der Laan, Gerrit
• Pattrick, Richard A. D
• Vaughan, David J
• Arenholz, Elke
• Lloyd, Jonathan R

Titel

Optimizing Cr(VI) and Tc(VII) Remediation through Nanoscale Biomineral Engineering

Ist Teil von

• Environmental science & technology, 2010-04, Vol.44 (7), p.2577-2584

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2010

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• The influence of Fe(III) starting material on the ability of magnetically recoverable biogenic magnetites produced by Geobacter sulfurreducens to retain metal oxyanion contaminants has been investigated. The reduction/removal of aqueous Cr(VI) was used to probe the reactivity of the biomagnetites. Nanomagnetites produced by the bacterial reduction of schwertmannite powder were more efficient at reducing Cr(VI) than either ferrihydrite “gel”-derived biomagnetite or commercial nanoscale Fe3O4. Examination of post-exposure magnetite surfaces indicated both Cr(III) and Cr(VI) were present. X-ray magnetic circular dichroism (XMCD) studies at the Fe L 2,3-edge showed that the amount of Fe(III) “gained” by Cr(VI) reduction could not be entirely accounted for by “lost” Fe(II). Cr L 2,3-edge XMCD spectra found Cr(III) replaced ∼14%−20% of octahedral Fe in both biogenic magnetites, producing a layer resembling CrFe2O4. However, schwertmannite-derived biomagnetite was associated with approximately twice as much Cr as ferrihydrite-derived magnetite. Column studies using a γ-camera to image a 99mTc(VII) radiotracer were performed to visualize the relative performances of biogenic magnetites at removing aqueous metal oxyanion contaminants. Again, schwertmannite-derived biomagnetite proved capable of retaining more (∼20%) 99mTc(VII) than ferrihydrite-derived biomagnetite, confirming that the production of biomagnetite can be fine-tuned for efficient environmental remediation through careful selection of the Fe(III) mineral substrate supplied to Fe(III)-reducing bacteria.