Iron oxides exist in a rich variety of structures and occur in a great variety of settings, from geological to nanoscale technological applications. Ferrous and ferric iron oxides present seven crystalline phases, the more common are α-Fe2O3 (hematite), γ-Fe2O3 (maghemite), Fe3O4 (magnetite) and Fe1-xO (wustite); the less commonly found are the βand ε-Fe2O3 phases and the low-temperature rhombo...

UndA(HRCR-6) was identified from the metal-reducing bacterium Shewanella sp. strain HRCR-6. Both in vivo and in vitro characterization results indicate that UndA(HRCR-6) is an outer membrane endecaheme c-type cytochrome and probably has a key functional role in the extracellular reduction of iron [Fe(III)] oxides and uranium [U(VI)] by Shewanella sp. HRCR-6.

An emerging area in chemical science is the study of solid-phase redox reactions using ultrafast time-resolved spectroscopy. We have used molecules of the photoactive dye 2',7'-dichlorofluorescein (DCF) anchored to the surface of iron(III) oxide nanoparticles to create iron(II) surface atoms via photo-initiated interfacial electron transfer. This approach enables time-resolved study of the fate...

introduction: iron cycle is one of the most important biogeochemical processes which affect the availability of iron in soils. ferric iron oxides are the most abundant forms of iron in soils and sediments. ferric iron is highly insoluble at circumneutral ph. present investigations have shown that the structural ferric iron bound in clay minerals is reduced by some microorganisms. anaerobic bact...

We have grown epitaxial films a few atomic layers thick of iron oxides on ruthenium. We characterize the growth by low energy electron microscopy. Using selected-area diffraction and intensity-versus-voltage spectroscopy, we detect two distinct phases which are assigned as wüstite and magnetite. Spin-polarized low energy electron microscopy reveals magnetic domain patterns in the magnetite phas...

Indurated surficial veneers are a characteristic phenomenon on exposures of unjointed granite in the southeastern states. They are caused by deposition of iron oxides in the interstices between the partially disaggregated mineral grains of the "sap" rock at the surface of the exposure. Breaching of veneers produces such peculiar erosional forms as weather pits, cavernous boulders, and pedestal ...

The geochemical fates of iron and arsenic are so closely correlated that methods of arsenic removal from water are in general based on the high adsorptive affinity of this metalloid with iron (hydr)oxides. Under anoxic conditions, however, reductive dissolution of iron (hydr)oxides can take place, and arsenic may be released into the surrounding environment. The purpose of this study was to inv...

A reactive transport model based on one-dimensional transport and equilibrium chemistry is applied to synoptic data from an acid mine drainage stream. Model inputs include streamflow estimates based on tracer dilution, inflow chemistry based on synoptic sampling, and equilibrium constants describing acid/base, complexation, precipitation/dissolution, and sorption reactions. The dominant feature...