Formation and crystallographical structure of hydroxysulphate and hydroxycarbonate green rusts synthetised by coprecipitation

Aissa, R.; François, Michel; Ruby, Christian; Fauth, François; Medjahdi, Ghouti; Abdelmoula, Mustapha; Génin, J.‐M. R.

doi:10.1016/j.jpcs.2006.01.020

Cited by 38 publications

(31 citation statements)

References 9 publications

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“…Fe II 4 Fe III 2 (OH) 12 CO 3 Á3H 2 O at stoichiometry, is characterised by an exceptional sharpness of lines, (Fig. 1aa) that were already observed in previous studies (Taylor, 1980;Drissi et al, 1995;Aïssa et al, 2006). This series of peaks are also clearly visible for x values of 0.5 and 0.67 showing that the GR(CO 3 2À ) original stacking sequence of cation layers and anion interlayers is maintained within the structure [ Fig.…”

Section: Oxidation Of Fesupporting

confidence: 69%

“…An Ag/AgCl electrode (3 M KCl) was used for measuring E h , but values were reported with respect to the standard hydrogen electrode, i.e. E h (V) = E Ag/AgCl (V) + 0.211 V. A 600 mL salt mixture of Fe(SO 4 )Á7H 2 O and Fe 2 (SO 4 ) 3 Á5H 2 O was progressively neutralised with 37 mL of Na 2 CO 3 solution ([Fe II ] = 2.2 Â 10 À2 M, [Fe III ] = 1.1 Â 10 À2 M, [Na 2 CO 3 ] = 1.1 M) (Bocher et al, 2004;Aïssa et al, 2006). The suspension got homogenous by stirring with a magnetic rod under a continuous flux of nitrogen bubbling.…”

Section: Synthesis Of Initial Fe Ii-iii Hydroxycarbonatementioning

confidence: 99%

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Oxidation modes and thermodynamics of FeII–III oxyhydroxycarbonate green rust: Dissolution–precipitation versus in situ deprotonation

Ruby

Abdelmoula²,

Naille³

et al. 2010

Geochimica et Cosmochimica Acta

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Fe II-III hydroxycarbonate green rust GR(CO 3 2À ), Fe II 4 Fe III 2 (OH) 12 CO 3 Á3H 2 O, is oxidized in aqueous solutions with varying reaction kinetics. Rapid oxidation with either H 2 O 2 or dissolved oxygen under neutral and alkaline conditions leads to the formation of ferric oxyhydroxycarbonate GR(CO 3 2À ) * , Fe III 6 O 12 H 8 CO 3 Á3H 2 O, via a solid-state reaction. By decreasing the flow of oxygen bubbled in the solution, goethite a-FeOOH forms by dissolution-precipitation mechanism whereas a mixture of non-stoichiometric magnetite Fe (3Àx) O 4 and goethite is observed for lower oxidation rates. The intermediate Fe II-III oxyhydroxycarbonate of formula Fe II 6(1Àx) Fe III 6x O 12 H 2(7À3x) CO 3 Á3H 2 O, i.e. GR(x) * for which x e [1/3, 1], is the synthetic compound that is homologous to the fougerite mineral present in hydromorphic gleysol; in situ oxidation accounts for the variation of ferric molar fraction x = [Fe III ]/{[Fe II ]+[Fe III ]} observed in the field as a function of depth and season but limited to the range [1/3, 2/3]. The domain of stability for partially oxidized green rust is observed in the E h -pH Pourbaix diagrams if thermodynamic properties of GR(x) * is compared with those of lepidocrocite, c-FeOOH, and goethite, a-FeOOH. Electrochemical equilibrium between GR(x) * and Fe II in solution corresponds to E h -pH conditions close to those measured in the field. Therefore, the reductive dissolution of GR(x) * can explain the relatively large concentration of Fe II measured in aqueous medium of hydromorphic soils containing fougerite.

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Section: Oxidation Of Fesupporting

confidence: 69%

Section: Synthesis Of Initial Fe Ii-iii Hydroxycarbonatementioning

confidence: 99%

Oxidation modes and thermodynamics of FeII–III oxyhydroxycarbonate green rust: Dissolution–precipitation versus in situ deprotonation

Ruby

Abdelmoula²,

Naille³

et al. 2010

Geochimica et Cosmochimica Acta

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“…It is important to recall here that the coprecipitation method from iron sulfates in alkaline carbonated solution leads first to the formation of GRðSO 2À 4 Þ, as explained by Aissa et al [20]. During a second step, GRðSO 2À 4 Þ is transformed into GRðCO 2À 3 Þ by an anion exchange mechanism within the GRðSO 2À 4 Þ interlayers between sulfate ions from the solid and carbonate ions from the solution.…”

Section: Physicochemical Characterization Of Green Rustsmentioning

confidence: 83%

“…Cl À ) or planar (e.g. CO 2À 3 ) anions are intercalated, the space group is R3m with a $ 3.17 Å and c $ 22.70 Å [19][20][21]. These green rusts are named green rusts one (GR1).…”

Section: Introductionmentioning

confidence: 99%

Carbonated ferric green rust as a new material for efficient phosphate removal

Barthélémy

Naille

Despas

et al. 2012

Journal of Colloid and Interface Science

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“…A long range order was determined for hydroxysulphate GR2(SO 2− 4 ) by XRD and confirmed by Mössbauer spectroscopy [2]. Such a feature could not be determined from XRD within GR1 [3]. Here the composition and crystallographic structure of various GR1s, hydroxycarbonate GR1(CO 2− 3 ), hydroxyoxalate GR1(C 2 O 2− 4 ), hydroxymethanoate (formate) GR1(HCOO − ), will be compared, as obtained either by coprecipitation of Fe II and Fe III ions or aerial oxidation of Fe(OH) 2 within solution containing the corresponding anion.…”

Section: Introductionmentioning

confidence: 95%

Structure of some FeII − III hydroxysalt green rusts (carbonate, oxalate, methanoate) from Mössbauer spectroscopy

Génin

Ruby

2008

Hyperfine Interact

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The abundances of Fe II and Fe III environments within green rusts one, GR1s, that intercalate carbonate, oxalate and methanoate (formate) anions are found from Mössbauer spectra for compositions corresponding to [Fe II 6 Fe III 2These formulae correspond to orders α, β and γ where cation distances are (2 × a 0 ), ( √ 3 × a 0 ) or a mixture of both leading to (7 × a 0 ), where ratio x = {[Fe III ]/[Fe total ]} = 1/4, 1/3 and 2/7, respectively. Anion distributions within interlayers are also devised and long-range orders determined accordingly.

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Formation and crystallographical structure of hydroxysulphate and hydroxycarbonate green rusts synthetised by coprecipitation

Cited by 38 publications

References 9 publications

Oxidation modes and thermodynamics of FeII–III oxyhydroxycarbonate green rust: Dissolution–precipitation versus in situ deprotonation

Oxidation modes and thermodynamics of FeII–III oxyhydroxycarbonate green rust: Dissolution–precipitation versus in situ deprotonation

Carbonated ferric green rust as a new material for efficient phosphate removal

Structure of some FeII − III hydroxysalt green rusts (carbonate, oxalate, methanoate) from Mössbauer spectroscopy

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