Effect of acetate on ferrihydrite crystallization

Abstract

M6ssbauer spectroscopy was used to follow the aging of ferrilaydrite with different amounts of acetate, to achieve more crystalline products. M6ssbauer spectra of fresh samples did not show any magnetic components. After two years aging, the solids presented crystalline fractions. Hematite formation was inhibited as acetate content increased in solids. For an acetate/ iron molar ratio equal to 0.63 goethite was formed instead of hematite. X-ray diffraction confirmed these results. This work shows that synthetic samples can be used for elucidating the "anti-bematitic" effect of organic matter already detected in soils.