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The Formation of Green Rust and Its Transformation to Lepidocrocite

Published online by Cambridge University Press:  09 July 2018

U. Schwertmann  and
H. Fechter
U. Schwertmann
Affiliation:
Lehrstuhl für Bodenkunde, Technische Universität München, 85350 Freising-Weihenstephan, Germany
H. Fechter
Affiliation:
Lehrstuhl für Bodenkunde, Technische Universität München, 85350 Freising-Weihenstephan, Germany
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Abstract

The formation of FeII,III hydoxy salts (green rusts) from FeII sulphate and chloride solutions and their transformation to lepidocrocite, γ-FeOOH, was studied at ambient temperature, constant pH of ∼7.0 and under controlled air flow. The formation of green rust and its subsequent transformation to lepidocrocite could be distinguished by the reaction rate and solution chemistry. The SO4 2− and Cl− concentrations in solution attain a minimum at the break between the two reaction steps and are completely restored to their initial values after complete transformation to lepidocrocite. While the green rust is being formed, its FeII/FeIII ratio shows a minor decrease and its FeIII/anion ratio a minor increase. These ratios, however, deviate from the ideal pyroaurite-type structure (M 2+/M 3+ = 3; M 3+/A − = 1; M: metal; A −: anion) and possibilities to accommodate this deviation are discussed. A period during which no protons were produced (i.e. no base consumed) was found to separate the two reactions in the chloride, but not in the sulphate system. During this period a partial solid state oxidation of the green rust took place, leading to its destabilization and eventual decomposition.

Information

Type
Research Article
Information
Clay Minerals , Volume 29 , Issue 1 , March 1994 , pp. 87 - 92
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1994

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References

Bender Koch, C. & Mørup, S. (1991) Identification of green rust in an ochre sludge. Clay Miner. 26, 577–582.Google Scholar
Bernal, J.O., Dasgupta, D.R. & MacKay, A.L. (1959) The oxides and hydroxides of iron and their structural interrelationships. Clay Miner. Bull.. 4, 15–30.Google Scholar
Brindley, G.W. & Bish, D.L. (1976) Green rust: a pyroaurite type structure. Nature 262, 353.Google Scholar
Cuitler, A.H., Man, V., Cranshaw, T.E. & Longworth, G. (1990) A Mössbauer study of green rust precipitates: I. Preparations from sulphate solutions. Clay Miner.. 25, 289–301.Google Scholar
Derie, R. & Ghodsi, M. (1972) Contribution à l’etude de la formation des sesquioxydes de Fe(III) monohydrates par aeration de gels d’hydroxyde de Fe(Il). Ind. Chim. Belg.. 37, 731–740.Google Scholar
Detournay, J., Ghodsi, M. & Derie, R. (1974) Etude cinetique de la formation de goethite par aeration de gels d’hydroxyde ferreux. Ind. Chim. Belg.. 39, 695–701.Google Scholar
Detournay, J., Derie, R. & Ghodsi, M. (1976) Etude de l’oxydation par aeration de Fe(OH)2 en milieu chlorure. Z. anorg. allg. Chem.. 427, 265–273.Google Scholar
Feitknecht, W. & Keller, G. (1950) Über die dunkel- griinen Hydroxylverbindungen des Eisens. Z. anorg. allg. Chem.. 262, 61–68.Google Scholar
Hansen, H.C.B. (1989) Composition, stabilization and light absorption of Fe(II)Fe(III)hydroxy carbonate (‘green rust’). Clay Miner. 24, 663–670.Google Scholar
Hansen, H.C.B. & Taylor, R.M. (1990) Formation of synthetic analogues of double metal-hydroxy carbonate minerals under controlled pH conditions: I. The synthesis of pyroaurite and reevesite. Clay Miner.. 25, 161–180.Google Scholar
Hansen, H.C.B. & Taylor, R.M. (1991) Formation of synthetic analogues of double metal-hydroxy carbonate minerals under controlled pH conditions: II. The synthesis of desautelsite. Clay Miner.. 26, 507–525.Google Scholar
McGill, I.R., McEnaney, B. & Smith, D.C. (1976) Crystal structure of green rust formed by corrosion of cast iron. Natur. 259, 200–201.Google Scholar
Murad, E. & Taylor, R.M. (1986) The oxidation of hydroxycarbonate green rusts. Pp. 585–593 in: Industrial Applications of the Mössbauer Effect (G.J. Long & J.G. Stevens, editors). Plenum Publ. Co., New York.Google Scholar
Mascolo, G. & Marino, O. (1980) A new synthesis and characterization of magnesium-aluminium hydroxides. Mineral. Mag.. 43, 619–621.Google Scholar
Rius, J. & Allmann, R. (1984) The superstructure of the double layer mineral wermlandite [Mg7(Al0.57,- Fe0.43 3+)(OH)18]2+[(Ca0.6, Mg0.4)(SO4)2(H2O)12]2- . Z. Krist.. 168, 133–144.CrossRefGoogle Scholar
Solcova, A., Subrt, J., Víns, J., Hanousek, F., Zapletal, V. & Tlaskal, J. (1981) Oxidation of ferrous sulphate in neutral and weakly alkaline solutions. Coll. Czech. Chem. Commun.. 46, 3049–3056.Google Scholar
Stampfl, P.P. (1969) Ein basisches Eisen-(II)-(lII)-Karbo- nat in Rost. Corr. Sci.. 9, 185–187.Google Scholar
Tamaura, Y. Yoshida, T. & Katsure, T. (1984) The synthesis of green rust, II (FeIII1-FcII2) and its spontaneous transformation into Fe304. Bull. Chem. Soc. Japa.. 57, 2411–2416.Google Scholar
Taylor, R.M. (1980) Formation and properties of Fe(II),- Fe(IIl) hydroxy-carbonate and its possible significance in soil formation. Clay Miner. 15, 369–382.Google Scholar
Taylor, R.M. (1984a) Influence of chloride on the formation of iron oxides from Fe(II) chloride. I. Effect of [Cl]/ [Fe] on the formation of magnetite. Clays Clay Miner.. 32, 167–174.Google Scholar
Taylor, R.M. (1984b) Influence of chloride on the formation of iron oxides from Fe(II) chloride. II. Effect of [Cl] on the formation of lepidocrocite and its crystallinity. Clays Clay Miner.. 32, 175–180.CrossRefGoogle Scholar
Taylor, R.M. & McKenzie, R.M. (1980) The influence of aluminum on iron oxides. VI. The formation of Fe(II)- Al(III)hydroxychlorides, -sulphates, and -carbonates as new members of the pyroaurite group and their significance in soils. Clays Clay Miner.. 28, 179–187.Google Scholar
Taylor, R.M. & Schwertmann, U. (1974) Maghemite in soils and its origin. II. Maghemite syntheses at ambient temperature and pH 7. Clay Miner.. 10, 299–310.Google Scholar
Víns, J., Zapletal, V. & Hanousek, F. (1987) Preparation and properties of green rust type substances. Coll. Czech. Chem. Commun.. 52, 93–102.Google Scholar