A spectroscopic study of uranium(VI) interaction with magnetite

Products of abiotic U(VI) reduction by biogenic magnetite and vivianite

“…For instance, Missana et al (2003), Regenspurg et al (2009) and Ilton et al (2010) reported SSA for synthetic magnetite of 19.7, 8.5 and 13.5 m 2 /g, respectively and corresponding reduction time of 27, 90 and 35 days for complete to near-complete reduction, respectively. Similarly, Aamrani et al (2007), Rovira et al (2007) and Duro et al (2008) and reported a SSA for commercial magnetite of about 1.6 m 2 /g and corresponding reduction time of 25, 85 and 60 days for complete to near-complete reduction, respectively. The stoichiometry of magnetite is also likely to play in role in modulating the rates of U(VI) reduction.…”

“…Magnetite formation has also been reported during biooxidation of Fe(II) coupled to denitrification (Chaudhuri et al, 2001). A number of studies have investigated the role of magnetite in uranium reduction and the findings varied greatly ranging from no observable reduction (Dodge et al, 2002) to clear evidence of reduction (Scott et al, 2005;Aamrani et al, 2007;O'Loughlin et al, 2010) to the formation of a mixed-valence U(IV)-U(VI) phase (Missana et al, 2003;Aamrani et al, 2007;Regenspurg et al, 2009) or the formation of U(V) (Ilton et al, 2010). The variation in findings is presumably linked to variability in morphology, specific surface area and phase stoichiometry Scherer, 2009, Gorski et al, 2010) of the magnetite used as well as differences in experimental conditions.…”

Quantitative analysis of Fe and Co in Co-substituted magnetite using XPS: The application of non-linear least squares fitting (NLLSF)

“…Most XPS studies of magnetite were focused on the determination of the Fe 2+ /Fe 3+ ratio [10,11] and the effects on the adsorption, reduction, or removal of heavy metals [12][13][14]. Few reports have examined the relative quantities of the substitution element and Fe in transition metalsubstituted magnetite, providing the motivation for the present study.…”

4th Annual DOE-ERSP PI Meeting: Abstracts

“…The goal of this project is to investigate the coupled biotic/abiotic pathways of Hg(II) reduction by DMRB. The research objectives are: (1) to quantify Hg(II) reduction by solid-phase Fe(II) minerals; and (2) to elucidate the abiotic and biotic pathways of Hg(II) reduction in complex enrichment cultures that are derived from saturated subsurface sediments .…”

“…The annual PI Meeting is very much a working meeting with three major goals: (1) to provide opportunities for scientific interaction among the ERSP scientists, a critical element for the program; (2) to provide the ERSP program staff with an opportunity to evaluate the progress of each program and project; and (3) to showcase the ERSP to interested parties within DOE and within other federal agencies. In addition to program managers from within OBER, there will be representatives from other offices within DOE and other federal agencies in attendance at the meeting.…”