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Effect of Cysteine and Manganese on the Crystallization of Noncrystalline Iron(III) Hydroxide at pH 8

Published online by Cambridge University Press:  02 April 2024

R. M. Cornell ,
R. Giovanoli  and
W. Schneider
R. M. Cornell
Affiliation:
ETHZ Zürich, Laboratory for Inorganic Chemistry, CH-8092 Zürich, Switzerland
R. Giovanoli
Affiliation:
University of Berne, Laboratory for Electronmicroscopy, Freiestrasse 3, CH-3000 Berne 9, Switzerland
W. Schneider
Affiliation:
ETHZ Zürich, Laboratory for Inorganic Chemistry, CH-8092 Zürich, Switzerland
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Abstract

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To provide a greater understanding of the crystallization of iron oxides under natural aqueous conditions, the combined effect of an inorganic ion (Mn2+) and a reducing organic ligand (L-cysteine) on the conversion of noncrystalline ferric hydroxide to goethite and/or hematite was investigated at pH 8.

At cysteine: Fe ratios ≥ 0.2, L-cysteine caused noncrystalline iron(III) hydroxide to transform rapidly into goethite at pH 8; in the absence of the organic ligand, hematite was the predominant reaction product. The presence of Mn (≥9 mole %) in the cysteine-ferric hydroxide system retarded crystallization and reduced the goethite-promoting effect of cysteine.

Polarographic measurements showed that the adsorption of cysteine on noncrystalline iron(III) hydroxide was immediately followed by the oxidation of cysteine to the disulfide with simultaneous reduction of a proportion of the interracial ferric ions. The partly reduced noncrystalline iron(III) hydroxide dissolved at pH 8 more rapidly than the original material, thus facilitating the formation of goethite. In Mn(II)-noncrystalline iron(III) hydroxide coprecipitates, the interfacial oxidation/reduction reaction with cysteine (and hence the partial reduction of the noncrystalline phase) was reduced, due to replacement of some interfacial Fe(III) by non-reducible Mn.

At pH 8, uptake of Mn by crystalline iron oxides was low (< 5 mole %). Mn precipitated preferentially as pure Mn phases, either rhodochrosite (in NaHCO3 buffer) or hausmannite (in NH4Cl/NH3 buffer).

Keywords

CrystallizationCysteineFerrihydriteGoethiteIron oxidesManganese
Type
Research Article
Information
Clays and Clay Minerals , Volume 38 , Issue 1 , February 1990 , pp. 21 - 28
Copyright
Copyright © 1990, The Clay Minerals Society

References

Cornell, R. M., 1985 Effect of simple sugars on the alkaline transformation of ferrihydrite into goethite and hematite Clays & Clay Minerals 33 219 – 227.CrossRefGoogle Scholar
Cornell, R. M., 1987 Comparison and classification of the effects of simple ions and molecules upon the transformation of ferrihydrite into more crystalline products Z. Pflanzenerndhr. Dung. Bodenkd. 150 304 – 307.CrossRefGoogle Scholar
Cornell, R. M., 1988 The influence of some divalent cations on the transformation of ferrihydrite to more crystalline products Clay Miner. 23 329 – 332.CrossRefGoogle Scholar
Cornell, R. M. and Giovanoli, R., 1985 Effect of solution conditions on the proportion and morphology of goethite formed from ferrihydrite Clays & Clay Minerals 33 424 – 432.CrossRefGoogle Scholar
Cornell, R. M. and Giovanoli, R., 1987 Effect of manganese on the transformation of ferrihydrite into goethite and jacobsite in alkaline media Clays & Clay Minerals 35 11 – 20.CrossRefGoogle Scholar
Cornell, R. M. and Giovanoli, R., 1988 The influence of copper on the transformation of ferrihydrite (5Fe2O, · 9H2O) into crystalline products in alkaline media Polyhedron 7 385 – 391.CrossRefGoogle Scholar
Cornell, R. M. and Schneider, W., 1989 Formation of goethite from ferrihydrite at physiological pH under the influence of cysteine Polyhedron 8 149 – 155.CrossRefGoogle Scholar
Davies, S. R. H., 1984 Mn(II) oxidation in the presence of metal oxides California California Institute of Technology, Pasadena.Google Scholar
Feitknecht, W., Giovanoli, R., Michaelis, W. and Müller, M., 1973 Über die Hydrolyse von Eisen(III)salzlösungen. I. Die Hydrolyse der Lösungen von Eisen(III)chlorid Helv. Chim. Acta 56 2847 – 2856.CrossRefGoogle Scholar
Lewis, D. G. and Schwertmann, U., 1979 The influence of A1 on iron oxides. Part III. Preparation of A1 goethites in M KOH Clay Miner. 14 115 – 126.CrossRefGoogle Scholar
Lindsay, W. L., 1979 Chemical Equilibria in Soils New York Wiley 157.Google Scholar
Mairesse-Ducarmoir, C. A., Patriarche, G. L. and Vandenbalck, J. L., 1974 Contribution à L’electrochimie des thiols et disulfures. Partie I. Cystéine et cystine Anal. Chim. Acta 71 165 – 174.CrossRefGoogle Scholar
McAuliffe, C. A. and Murray, S. G., 1972 Metal complexes of sulphur-containing amino acids Inorg. Chim. Acta Reviews 6 103 – 172.CrossRefGoogle Scholar
Schwertmann, U., 1984 Differenzierung der Eisenoxides des Bodens durch Extraktion mit einer Ammoniumoxalatlösung Z. Pflanzenernähr. Düng. Bodenkd. 105 194 – 202.CrossRefGoogle Scholar
Stiers, W. and Schwertmann, U., 1985 Evidence for manganese Substitution in synthetic goethite Geochim. Cosmochim. Acta 49 1909 – 1911.CrossRefGoogle Scholar