Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-05T16:08:46.285Z Has data issue: false hasContentIssue false

Long-term in vitro transformation of 2-line ferrihydrite to goethite/hematite at 4, 10, 15 and 25°C

Published online by Cambridge University Press:  09 July 2018

U. Schwertmann*
Affiliation:
Institute of Soil Science, Technical University of Munich, Freising-Weihenstephan, Germany
H. Stanjek
Affiliation:
Institute of Soil Science, Technical University of Munich, Freising-Weihenstephan, Germany
H.-H. Becher
Affiliation:
Institute of Soil Science, Technical University of Munich, Freising-Weihenstephan, Germany
*

Abstract

2-line ferrihydrite stored in water at ambient temperatures from 4 to 25°C and at ten different pH values between 2.5 and 12 for up to 10–12 y transformed to both goethite and hematite at all temperatures and pH values except at pH 12 where only goethite was formed. The rate and degree of transformation (20–100%) increased with increasing pH and temperature. The hematite/ (hematite+goethite) ratio varied between 0 and ~0.8, increased with increasing temperature and showed a strong maximum at pH 7–8 which increased from 0.1–0.2 at 4°C to 0.7–0.8 at 25°C. The maximum coincides with the zero point of charge of ferrihydrite where its solubility and, thus, its via-solution transformation rate to goethite are minimal. We assume, therefore, that in this pH-range the (slower) via-solution transformation to hematite can more efficiently compete with that to goethite.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bao, H. & Koch, P.L. (1999) Oxygen isotope fractionation in ferric oxide-water systems: Low temperature synthesis. Geochimica et Cosmochimica Ada, 63, 599–613.Google Scholar
Bao, H., Koch, P.L. & Thiemes, M.H. (2000) Oxygen isotope composition of ferric oxides from recent soil, hydrologic, and marine environments. Geochimica et Cosmochimica Ada, 64, 2221–2231.CrossRefGoogle Scholar
Carlson, L. & Schwertmann, U. (1981) Natural ferrihydrites in surface deposits from Finland and their association with silica. Geochimica et Cosmochimica Ada, 45, 421–429.Google Scholar
Carlson, L. & Schwertmann, U. (1987) Iron and manganese oxides in Finnish ground water treatment plants. Water Research, 21, 165170.CrossRefGoogle Scholar
Campbell, A.S. & Schwertmann, U. (1984) Iron oxide mineralogy of placic horizons. Journal of Soil Science, 35, 569–582.Google Scholar
Campbell, A.S., Schwertmann, U., Stanjek, H., Kyek, A. & Campbell, B.A. (2002) Si incorporation into hematite by heating Si-ferrihydrite. Langmuir, 18, 7804–7809.CrossRefGoogle Scholar
Cornell, R.M. & Schwertmann, U. (2003) The Iron Oxides, 2nd edition. Wiley-VCH, New York, 613 pp.CrossRefGoogle Scholar
Dzombak, A.D. & Morel, F.M.M. (1990) Surface Complex Modelling. Hydrous Ferric Oxide. J. Wiley, Germany, 393 pp.Google Scholar
Farley, K.I., Dzombak, A.D. & Morel, F.M.M. (1985) A surface precipitation for the adsorption of cations on metal oxides. Journal of Colloid and Interface Science, 106, 226242.CrossRefGoogle Scholar
Schwertmann, U. (1964) Differenzierung der Eisenoxide des Bodens durch Extraktion mit Ammoniumoxalat-Lösung. Zeitschrifi für Pflanzenernahrung und Bodenkunde, 105, 194202.CrossRefGoogle Scholar
Schwertmann, U. (1988) Occurrence and formation of iron in various pedoenvironments. Pp. 267—302 in. Iron in Soils and Clay Minerals (Stucki, J.W., Goodman, B.A. & Schwertmann, U., editors). NATO ASI Series C 217.Google Scholar
Schwertmann, U. & Murad, E. (1982) The nature of an iron oxide-organic association. Clay Minerals, 23, 291–299.Google Scholar
Schwertmann, U., Schulze, D.G. & Murad, E. (1982) Identification of ferrihydrite in soils by dissolution kinetics, differential X-ray diffraction and Mossbauer spectroscopy. Soil Science Society of America Journal, 46, 869–875.Google Scholar
Schwertmann, U., Carlson, L. & Murad, E. (1987) Properties of iron oxides in two Finnish lakes in relation to the environment of their formation. Clays and Clay Minerals, 35, 297–304.Google Scholar
Schwertmann, U., Friedl, J. and Stanjek, H. (1999) From Fe(III) ions to ferrihydrite and then to hematite. Journal of Colloid and Interface Science, 209, 215223.CrossRefGoogle ScholarPubMed
Schwertmann, U., Friedl, J., Stanjek, H. and Schulze, D.G. (2000) The effect of clay minerals on the formation of goethite and hematite from ferrihydrite after 16 years of aging at 25°C and pH 4—7. Clay Minerals, 35, 613–623.Google Scholar
Towe, K.M. & Bradley, W.F. (1967) Mineralogical constitution of colloidal ‘hydrous ferric oxides'. Journal of Colloid and Interface Science, 24, 384–392.Google Scholar