Reactions of ferrous iron with hematite

Jeon, Byong‐Hun; Dempsey, Brian A.; Burgos, William D.; Royer, Richard A.

doi:10.1016/s0927-7757(01)00762-2

Cited by 104 publications

(115 citation statements)

References 45 publications

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“…Fe(II) uptake increases with increasing pH, as well as with increasing Fe(II) concentration, which is consistent with previous studies on Fe(III) mineral phases (i.e. [Dixit and Hering, 2006;Jeon et al, 2001;Liger et al, 1999]). It should be noted that at pH 8.3, the samples were oversaturated with respect to Fe(OH) 2 above 0.55 mM.…”

Section: Fe(ii) Uptake and Transformationsupporting

confidence: 92%

Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field Scale Subsurface Research Challenge Site at Rifle, Colorado, February 2011 to January 2012

Long¹

2012

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Section: Fe(ii) Uptake and Transformationsupporting

confidence: 92%

Microbiological, Geochemical and Hydrologic Processes Controlling Uranium Mobility: An Integrated Field Scale Subsurface Research Challenge Site at Rifle, Colorado, February 2011 to January 2012

Long¹

2012

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“…Dzombak and Morel found that they had to invoke strong and weak sorption sites to describe experimental results for sorption edges and sorption isotherms, and they reported 0.005 and 0.200 mol sorption sites per mol of Fe(III) for strong and weak sites, respectively. Jeon et al (2001) studied sorption of Fe(II) onto hematite and onto HFO, and reported sorption at both strong and weak sorption sites, with similar relative concentrations as reported by Dzombak and Morel. Dietz (2003) studied the sorption and oxidation of Fe(II) in the presence of ferric oxides that formed during treatment of AMD at slightly acidic pH values, as in passive treatment systems.…”

Section: Introductionsupporting

confidence: 53%

Mechanisms of Heterogeneous Fe(ii) Oxidation in Acid Mine Drainage

Park¹,

Dempsey²

2004

JASMR

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Abstract. The objective of the study was to investigate the sorption and abiotic oxidation of ferrous iron at ferric oxide surfaces at pH 6.8 and 7.0, and to identify changes in ferric oxide phase during the sorption and oxidation processes. Our group previously reported on mechanisms for sorption and heterogeneous oxidation at pH less than 6.5 and on the characteristics of ferric oxide sludge. We have also reported on transformations from amorphous to crystalline ferric oxides as a function of pH and solution composition. Sorption experiments were conducted at room temperature in an anaerobic chamber with 97% N 2 and 3% H 2 . An additional oxygen trap was used to ensure an anoxic environment. The Fe(II)/Fe(III) ratio and pH were varied. The rate and extent of sorption of Fe(II) were monitored. Changes in solid phases were monitored using 57 Fe-Mössbauer Spectroscopy. Subsequent to sorption, oxidation rate constants and mechanisms were evaluated after exposure to very low partial pressures of O 2 . The results showed that oxidation processes that occurred with high Fe(III) to Fe(II) ratios were more complicated in the neutral pH range compared to pH < 6.5, due to phase transformations that resulted in short-term sorption anomalies, such as decreased sorption after conversion from amorphous ferric oxide to goethite or precipitation of mixed Fe(II)/Fe(III) phases that slowly became inert to oxidation. These results are important in the context of treatment processes for AMD that depend on the presence of a ferric oxide phase, that is for high-density sludge processes that result in heterogeneous oxidation of Fe(II) and that are conducted at slightly acid to alkaline pH values.Additional

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“…Lesser amounts of Fe(II) sorption were observed for reactions at pH 5.5 and 6.5, and no net Fe(II) sorption, within error, was observed at pH 2.5. The enhanced Fe(II) uptake by goethite with increasing pH (Figure 1) is expected for cation sorption to oxide surfaces (Jeon et al, 2001(Jeon et al, , 2003; Strathmann and Stone, M A N U S C R I P T…”

Section: Resultsmentioning

confidence: 91%