Transformation of 2-line ferrihydrite to 6-line ferrihydrite under oxic and anoxic conditions

Kukkadapu, Ravi; Zachara, John M.; Fredrickson, James K.; Smith, Steven C.; Dohnálková, Alice; Russell, Colleen K.

doi:10.2138/am-2003-11-1233

Cited by 119 publications

(79 citation statements)

References 44 publications

(67 reference statements)

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“…1), consistent with previous reports for pure 2-line Fh [38,39], which suggested that the presence of PHF did not significantly affect the structure of Fh. According to the results of element analysis (Table 1), the contents of carbon element for 1.2%PHF/Fh, 2.3%PHF/Fh, 4.7%PHF/Fh, and 9.4%PHF/Fh were 0.81, 1.26, 2.06, and 3.67 wt%, respectively.…”

Section: Structural Characterization Resultssupporting

confidence: 92%

Fullerol modification ferrihydrite for the degradation of acid red 18 under simulated sunlight irradiation

Liu

Zhou

et al. 2016

Journal of Molecular Catalysis A: Chemical

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Section: Structural Characterization Resultssupporting

confidence: 92%

Fullerol modification ferrihydrite for the degradation of acid red 18 under simulated sunlight irradiation

Liu

Zhou

et al. 2016

Journal of Molecular Catalysis A: Chemical

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“…2a) and 24 h (Fig. 2b) showed quadrupole doublets with the hyperfine parameters (IS = 0.35 mm/s, QS = 0.70 mm/s) similar to typical HFO (e.g., Cornell and Schwertmann 1996;Mitov et al 2002;Kukkadapu et al 2003). The spectrum of 60 h (Fig.…”

Section: Mössbauer Hyperfine Parametersmentioning

confidence: 81%

Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

Zhu

Deng

2011

Phys Chem Minerals

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Amorphous ferric iron species (ferrihydrite or akaganeite of \5 nm in size) is the only known solid ferric iron oxide that can be reductively transformed by dissimilatory iron-reducing bacteria to magnetite completely. The lepidocrocite crystallite can be transformed into magnetite in the presence of abiotic Fe(II) at elevated pH or biogenic Fe(II) with particular growth conditions. The reduction of lepidocrocite by dissimilatory iron-reducing bacteria has been widely investigated showing varying results. Vali et al.

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“…Silica was co-precipitated with ferrihydrite to retard the progress of oxidative recrystallization reactions (e.g., to 6-line ferrihydrite, goethite, and hematite) that proceed relatively rapidly in its absence (Anderson and Benjamin, 1985;Kukkadapu et al, 2003;Dyer et al, 2010). The resulting ferrihydrite suspension was washed with 1.0 Â 10 À4 mol L À1 NaClO 4 to remove nitrate and dissolved Si, and (1) stored as $5.0 Â 10 À1 mol L À1 Fe suspension (pH 7.0) in 1.0 Â 10 À4 mol L…”

mentioning

confidence: 99%

The mineralogic transformation of ferrihydrite induced by heterogeneous reaction with bioreduced anthraquinone disulfonate (AQDS) and the role of phosphate

Zachara¹,

Kukkadapu²,

Peretyazhko³

et al. 2011

Geochimica et Cosmochimica Acta

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Bruce, "The mineralogic transformation of ferrihydrite induced by heterogeneous reaction with bioreduced anthraquinone disulfonate (AQDS) and the role of phosphate" (2011 Abstract Bioreduced anthraquinone-2,6-disulfonate (AH 2 DS; dihydro-anthraquinone) was reacted with a 2-line, Si-substituted ferrihydrite under anoxic conditions at neutral pH in PIPES buffer. Phosphate (P) and bicarbonate (C); common adsorptive oxyanions and media/buffer components known to effect ferrihydrite mineralization; and Fe(II) aq (as a catalytic mineralization agent) were used in comparative experiments. Heterogeneous AH 2 DS oxidation coupled with Fe(III) reduction occurred within 0.13-1 day, with mineralogic transformation occurring thereafter. The product suite included lepidocrocite, goethite, and/or magnetite, with proportions varing with reductant:oxidant ratio (r:o) and the presence of P or C. Lepidocrocite was the primary product at low r:o in the absence of P or C, with evidence for multiple formation pathways. Phosphate inhibited reductive recrystallization, while C promoted goethite formation. Stoichiometric magnetite was the sole product at higher r:o in the absence and presence of P. Lepidocrocite was the primary mineralization product in the Fe(II) aq system, with magnetite observed at near equal amounts when Fe(II) was high [Fe(II)/Fe(III)] = 0.5 and P was absent. P had a greater effect on reductive mineralization in the Fe(II) aq system, while AQDS was more effective than Fe(II) aq in promoting magnetite formation. The mineral products of the direct AH 2 DS-driven reductive reaction are different from those observed in AH 2 DS-ferrihydite systems with metal reducing bacteria, particularly in presence of P. Ó

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Transformation of 2-line ferrihydrite to 6-line ferrihydrite under oxic and anoxic conditions

Cited by 119 publications

References 44 publications

Fullerol modification ferrihydrite for the degradation of acid red 18 under simulated sunlight irradiation

Fullerol modification ferrihydrite for the degradation of acid red 18 under simulated sunlight irradiation

Mössbauer hyperfine parameters of iron species in the course of Geobacter-mediated magnetite mineralization

The mineralogic transformation of ferrihydrite induced by heterogeneous reaction with bioreduced anthraquinone disulfonate (AQDS) and the role of phosphate

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