Microbial (Geobacter sulfurreducens) reduction of 0.1 mM U(VI) in the presence of synthetic Fe(III) oxides and natural Fe(III) oxide-containing solids was investigated in pH 6.8 artificial groundwater containing 10 mM NaHCO3. In most experiments, more than 95% of added U(VI) was sorbed to solids, so that U(VI) reduction was governed by reactions at the solid-water interface. The rate and extent...

Biogeochemistry is a useful tool for assessing geochemical dispersion patterns. Sari Gunay epithermal gold deposit was selected in order to assess the application of biogeochemical exploration for gold in northwestern Iran. In this study, four sites were sampled in a profile perpendicular to mineralized vein with a control site two km far-off mineralized vein. A sample from each dominant plant ...

BACKGROUND AND METHODS Magnetic iron oxide nanoparticles were prepared using a sonochemical method under atmospheric conditions at a Fe²⁺ to Fe³⁺ molar ratio of 1:2. The iron oxide nanoparticles were subsequently coated with chitosan and gallic acid to produce a core-shell structure. RESULTS X-ray diffraction demonstrated that the magnetic nanoparticles were pure Fe₃O₄ with a cubic inverse sp...

The oxidation of iron (Fe) by water (D2O) vapour at low pressures and room temperature was investigated using time-of-flight (ToF) SIMS. The results supported those found previously using XPS and the QUASES program in that a duplex oxide structure was found containing a thin outer surface hydroxide (Fe(OD)2) layer over an inner oxide (FeO) layer. The extraordinary depth resolution of the ToF-S...

The initial oxidation stages of copper and copper-iron alloys have been studied by the AtomProbe Field Ion Microscope (AP-FIM). The depth profiles of copper oxide formed in-situ were successfully determined. The composition of the oxide was close to the value of Cu20, but a large concentration fluctuation was found. The interface between the oxide and the metal was found to be diffuse, the widt...

Lovley, D.R., Roden, E.E., Phillips, E.J.P. and Woodward, J.C., 1993. Enzymatic iron and uranium reduction by sulfatereducing bacteria. In: R.J. Parkes, P. Westbroek and J.W. de Leeuw (Editors), Marine Sediments, Burial, Pore Water Chemistry, Microbiology and Diagenesis. Mar. Geol., 113: 41-53. The potential for sulfate-reducing bacteria (SRB) to enzymatically reduce Fe(III) and U(VI) was inves...

We report the electrochemical characterization of chitosan films deposited at gold electrodes from an acidic solution at reducing potentials. Cyclic voltammetry was used to characterize the deposition and electroactivity of chitosan coated gold electrodes. Chitosan films were found to deposit at gold electrodes at potentials more negative than −1.0 V versus Ag/AgCl, a potential associated with ...