The effect of water content on the magnetic and structural properties of goethite

Betancur, Juan David; Barrero, C. A.; Grenèche, Jean‐Marc; Goya, G.F.

doi:10.1016/j.jallcom.2003.09.046

Cited by 26 publications

(21 citation statements)

References 10 publications

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“…1, top spectrum) exhibits a broad band in the 2600-3800 cm À1 region, two sharper bands of lower intensity in the 1600-1800 cm À1 region and two other bands in the 700-900 cm À1 region. These features are consistent with previously published values for synthetic goethite (Schwarzmann and Sparr, 1969;Parfitt et al, 1975;Rochester and Topham, 1979a,b;Busca et al, 1978;Verdonck et al, 1982;Morterra et al, 1984;Ishikawa et al, 1986;Williams and Guenther, 1996;Weckler and Lutz, 1998;Ruan et al, 2001Ruan et al, , 2002Krehula et al, 2002;Subbanna et al, 2002;Betancur et al, 2004). All bands undergo substantial changes with temperature, as it will be discussed further in Section 3.2.…”

Section: Ftir Spectra Of Goethitesupporting

confidence: 90%

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

Boily

Szanyi

Felmy

2006

Geochimica et Cosmochimica Acta

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Section: Ftir Spectra Of Goethitesupporting

confidence: 90%

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

Boily

Szanyi

Felmy

2006

Geochimica et Cosmochimica Acta

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“…Because of relatively high amount of the total Fe (41 %) contributing to the doublet signal, we assume that the doublet could be attributed to iron atoms bound in small particle-size or Al-substituted Fe (oxyhydr)oxides also. Both Al substitution and small particlesize often lead to the decrease of the magnetic ordering temperature of Fe (oxyhydr)oxides (Golden et al 1979;Murad 1988Murad , 1989Friedl & Schwertmann 1996;Betancur et al 2004). The Mössbauer spectrum of the sample J45 contains four sextets at 80 K (Fig.…”

Section: Mössbauer Spectroscopymentioning

confidence: 99%

Experimental interactions of Slovak bentonites with metallic iron

Osacký¹,

Honty²,

Madejová³

et al. 2009

Geologica Carpathica

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Abstract:The experimental stability of four bentonites and one K-bentonite from Slovak deposits in the presence of iron was studied to simulate the possible reactions of clays (bentonite barrier) in the contact with Fe containers in a nuclear waste repository. The batch experiments were performed at 60 °C for 30 and 120 days in aerobic conditions. The reaction products were examined by XRD, FTIR, and Mössbauer spectroscopies and CEC (cation exchange capacities) were determined. Reaction solutions were analysed for selected elements using AAS (atomic absorption spectrometry). The results show that bentonites do not interact equally with metallic iron. Bentonites from the Jelšový Potok, Kopernica and Lieskovec deposits reacted similarly whereas the interaction between the bentonite from Lastovce and the iron was less intensive. The lower reactivity of the bentonite from Lastovce can be explained by its low content of smectite. During iron-clay interactions the iron was consumed and Fe oxides (magnetite, lepidocrocite) were formed. Decrease of the smectite diffraction peaks intensity and CEC values during the experiments show rather the rearrangement of the original smectite crystals than dissolution of smectite. In the K-bentonite from the Dolná Ves deposit where the mixed-layer illite-smectite is present instead of smectite, the dissolution of illite-smectite was observed along with the neoformation of smectite. The structure of illite-smectite deteriorated more than the structure of smectites which suggests that this mixed-layer illite-smectite is much less stable in the presence of iron than smectites.

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“…Time scale of 57 Fe absorber based Mossbauer spectroscopy is comparable to spin relaxation time of nano particles with size up to 10 nm at room temperature thus making it a powerful tool for addressing aspects related to magnetism of nano particles. In addition the effect of particle size and crystal structure, 11 magnetic relaxation, 16,37,38 doping effects on the structural and magnetic properties of goethite and the transformation to hematite 18,48 due to dehydration have been addressed in a detailed manner by many researchers using Mossbauer spectroscopy. 18,35,39 In contrast to ferromagnetic nano particles, 33 being anti ferro magnetically ordered the dipole interaction between nano particles of α-FeOOH is negligible.…”

Section: Introductionmentioning

confidence: 99%

Atomic scale study of thermal reduction of nano goethite coexisting with magnetite

et al. 2013

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Evolution of the local structure and magnetic properties of nano particles of goethite having magnetite as a composite due to controlled annealing treatments in vacuum has been studied using Mossbauer spectroscopy. Importance of size, defect associated with structural OH- for the observed structural and magnetic properties of goethite has been emphasized in this study. Present Mossbauer results show that thermal annealing at low temperatures (420-550 K) lead to a partial conversion / reduction of orthorhombic goethite to cubic spinel oxides such as maghemite and off-stochiometric magnetite. This study further establishes that annealing treatments beyond 650 K predominantly results in topotactic conversion of goethite to haematite. Underlying physics of the transitions of goethite to iron oxides and the important role of desorbed hydrogen for the orthorhombic to cubic structural transitions has been elucidated in this study.

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The effect of water content on the magnetic and structural properties of goethite

Cited by 26 publications

References 10 publications

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

A combined FTIR and TPD study on the bulk and surface dehydroxylation and decarbonation of synthetic goethite

Experimental interactions of Slovak bentonites with metallic iron

Atomic scale study of thermal reduction of nano goethite coexisting with magnetite

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