Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sumoondur, A. Articles by Benning, L. G. Search for Related Content GeoRef GeoRef Citation

Green rust as a precursor for magnetite: an in situ synchrotron based study

Earth and Biosphere Institute, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK

^* E-mail: a.sumoondur{at}see.leeds.ac.uk

ABSTRACT

In this study, direct evidence for the formation of magnetite via a green rust intermediate is reported. The Fe(II) induced transformation of ferrihydrite, was quantified in situ and under O₂-free conditions using synchrotron-based time-resolved energy dispersive X-ray diffraction. At pH 9 and Fe(II)/Fe(III) ratios of 0.5 and 1, rapid growth (6 min) of sulphate green rust and its subsequent transformation to magnetite was observed. Electron microscopy confirmed these results, showing the initial rapid formation of hexagonal sulphate green rust particles, followed by the corrosion of the green rust as magnetite growth occurred, indicating that the reaction proceeds via a dissolution-reprecipitation mechanism. At pH 7 and Fe(II)/Fe(III) ratio of 0.5, sulphate green rust was the stable phase, with no transformation to magnetite.

KEYWORDS: magnetite, green rust, nanoparticulate, synchrotron, diffraction