Influence of aging in an alkaline medium on the microstructural properties of α-FeOOH

Krehula, Stjepko; Musić, Svetozar

doi:10.1016/j.jcrysgro.2007.10.072

Cited by 73 publications

(39 citation statements)

References 23 publications

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“…The main IR bands at 896 and 798 cm -1 are usually used in the identification of goethite. [14][15][16] These IR bands were assigned to the Fe-O-H in-plane bending (δOH) and out-of-plane bending (γOH) vibrations, respectively. The broad IR band at 3436 cm -1 was due to the stretching -OH vibrations of adsorbed H2O molecules, whereas the IR band at 1636 cm -1 was due to the bending -OH vibrations.…”

Section: Resultsmentioning

confidence: 99%

57Fe Mössbauer, XRD, FT-IR, FE SEM Analyses of Natural Goethite, Hematite and Siderite

et al. 2017

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Natural goethite, hematite and siderite were analysed with 57 Fe Mössbauer, XRD and FT-IR. FE SEM images of samples were also taken. The Mössbauer spectra of limonite (α-FeOOH · nH2O) from Budapest (Hungary), Ljubija (Bosnia and Herzegovina) and Korçё (Albania) showed the same type of spectrum, indicating low crystallinity and broad particle size distribution. All goethite particles from these three locations were one-dimensional (1D), but with different nano/microstructures. A very early precursor of limonite from Budapest and Ljubija locations was assigned to FeS2 (pyrite and/or marcasite) which oxidised upon ventilation (oxygenation) under hydrogeothermal conditions, thus producing FeSO4 and Fe2(SO4)3. In the next step limonite deposits were formed. The similarity between this limonite formation under hydrogeothermal conditions and the chemical precipitation of goethite from FeSO4 or Fe2(SO4)3 solutions at laboratory level was briefly discussed. The deposition of lateritic goethite at the Korçë location is presumed to be due to the chemical weathering (tropical conditions) of ultramafic rocks. Under the same conditions and a proper pH the transformation of goethite to hematite is possible. Alternatively, the oxidation of Fe 2+ in magnetite and its transformation to hematite via maghemite (γ-Fe2O3) as an intermediate could have taken place. The Mössbauer spectrum of siderite from the Ljubija location showed a quadrupole doublet with asymmetric spectral lines. This asymmetry could be assigned to the Goldanskii-Karyagin effect, however, the contribution of the crystallite texture to this asymmetry cannot be excluded. Hematite and a small fraction of siderite at the Vareš location (Bosnia-Herzegovina) are of metasomatic origin deposited in limestone that now form a series of greatly metamorphosed sedimentary rocks. Hematite particles were deposited in the form of laminates (2D).

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Section: Resultsmentioning

confidence: 99%

57Fe Mössbauer, XRD, FT-IR, FE SEM Analyses of Natural Goethite, Hematite and Siderite

et al. 2017

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“…In the FT-IR spectrum of sample S2 the IR bands at 850, 697 and 640 cm -1 are due to -FeOOH and the IR bands at 574, 537 and 482 cm -1 are due to -Fe 2 O 3 . Two IR bands at 895 and 796 cm -1 are typical of -FeOOH and are assigned to the Fe-O-H bending vibration ( OH and  OH , respectively) [20]. The FT-IR spectrum of sample S3 shows only the presence of -Fe 2 O 3 and a small fraction of -FeOOH, whereas the FT-IR spectrum of sample S4 can be assigned to -Fe 2 O 3 as a single phase.…”

Section: Resultsmentioning

confidence: 99%

THE EFFECT OF SODIUM DODECYL SULPHATE ON THE FORCED HYDROLYSIS OF FeCl3 SOLUTIONS

Ristić¹,

Štajdohar²,

Opačak³

et al. 2017

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Precipitations by the forced hydrolysis of 0.2 M FeCl 3 aqueous solutions between 2 and 72 hours in the presence of 1% sodium dodecyl sulphate (SDS) were investigated. In the absence of SDS a direct phase transformation -FeOOH → -Fe 2 O 3 via dissolution/recrystallization occured in the precipitation system. In the presence of SDS, -FeOOH as an intermediate phase precipitated and, with a prolonged time of forced hydrolysis, also transformed to -Fe 2 O 3 via the dissolution/recrystallization mechanism. On the basis of Mössbauer spectra it was concluded that in the presence of SDS, -Fe 2 O 3 phase possessed a lower degree of crystallinity. In this precipitation process the competition between the stability of Fe(III)-dodecyl sulphate, on one side, and the formation of iron oxide phases, on the other, also played an important role. FE SEM revealed that the big -Fe 2 O 3 particles possessed the substructure. The elongation of primary -Fe 2 O 3 particles produced in the presence of SDS was noticed. This effect can be assigned to the preferential adsorption of dodecyl sulphate groups on nuclei and crystallites of FeOOH and -Fe 2 O 3 phase during the forced hydrolysis of FeCl 3 solutions.

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“…The FTIR peak at 3394 cm −1 can be assigned to physically absorbed water [13]. The peaks at 879 and 789 cm −1 are assigned to the Fe O H bending vibrations of goethite (␦OH and ␥OH, respectively) [31]. The peak at 633 cm −1 is assigned to the Fe O and Fe OH stretching or lattice vibrations [32,33].…”

Section: As(v) Adsorption Mechanismmentioning

confidence: 99%

Facile one-pot preparation of goethite/parabutlerite nanocomposites and their removal properties and mechanism toward As(V) ions

Fang¹,

Jia²,

Wu³

et al. 2015

Applied Surface Science

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Influence of aging in an alkaline medium on the microstructural properties of α-FeOOH

Cited by 73 publications

References 23 publications

57Fe Mössbauer, XRD, FT-IR, FE SEM Analyses of Natural Goethite, Hematite and Siderite

57Fe Mössbauer, XRD, FT-IR, FE SEM Analyses of Natural Goethite, Hematite and Siderite

THE EFFECT OF SODIUM DODECYL SULPHATE ON THE FORCED HYDROLYSIS OF FeCl3 SOLUTIONS

Facile one-pot preparation of goethite/parabutlerite nanocomposites and their removal properties and mechanism toward As(V) ions

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