The effect of dry heating on the chemistry, surface area, and oxalate solubility of synthetic 2-line and 6-line ferrihydrites
Authors:
- H. StanjekHSH. Stanjek
- P. G. WeidlerPWP. G. Weidler
- 1 December 1992
- journal article
- Published by Mineralogical Society in Clay Minerals
- Vol. 27 (4) , 397-411
Abstract
Synthetic 2-line and 6-line ferrihydrites were heated to 400 K, 500 K and 600 K, under dry conditions. Heating to 400 K lowered the ratios of structural OH to Fe2O3 without a phase transformation. The lowest ratios observed at 400 K were 1·23 (2-line) and 0·85 (6-line ferrihydrite) after 1150 h. For 6-line ferrihydrites heated to 400 K, the solubility in oxalate and the BET surface areas decreased with increasing heating time, whereas the unit-cell parameters, the relative peak intensities and the mean coherence lengths did not change significantly. Heating the 2-line ferrihydrites to 400 K produced microporosity.Keywords
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