Biotic Fe(III) reduction of magnetite coupled to H-2 oxidation: Implication for radioactive waste geological disposal

摘要

We report the first results on microbial Fe(III) reduction of magnetite in the presence of H-2 (4%, 10%, or 60% H-2) as the sole electron donor. The H-2 concentration is the parameter likely to control both chemical and biological dissolution of magnetite, and a direct correlation between H-2 concentration, bacterial activity, and the extent of Fe(III) bioreduction was observed. Vivianite was identified as a secondary mineral phase as a consequence of the increase in dissolved Fe(II) and the presence of phosphate in the experimental solutions. In the context of metal corrosion, Fe(III) bioreduction coupled to H-2 oxidation may affect the passivating properties of oxide layers made of magnetite. (C) 2015 Elsevier B.V. All rights reserved.