57Fe Moessbauer, FT-IR and TEM investigations of Fe-oxide powders obtained from concentrated FeCl3 solutions (CROSBI ID 82015)
Prilog u časopisu | Pismo (znanstveno) | međunarodna recenzija
Podaci o odgovornosti
Musić, Svetozar ; Santana, Genilson ; Šmit, Goran ; Garg, V.K.
engleski
57Fe Moessbauer, FT-IR and TEM investigations of Fe-oxide powders obtained from concentrated FeCl3 solutions
The chemical and microstructural properties of oxide phases precipitated from concentrated FeCl3 solutions were investigated using Fe-57 Mossbauer spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy. The initial pH of the precipitation system (acidic or highly alkaline medium) determined the mechanism of phase transformations. In a highly alkaline medium two competitive mechanisms exist: (a) the nucleation and crystal growth of alpha-Fe2O3 inside the condensed Fe(OH)(3) gel and (b) the crystallization of alpha-FeOOH which transforms to alpha-Fe2O3 by a dissolution/reprecipitation mechanism. In the present work, spectroscopic results indicated that before a-FeOOH was detectable (or formed) at 60 degrees C, superparamagnetic and/or amorphous Fe-oxide particles (probably alpha-Fe2O3) were formed. Once alpha-FeOOH was formed, its fraction in the precipitate increased rapidly. In an acidic medium (partially neutralized FeCl3 solution) alpha-Fe2O3, was formed from beta-FeOOH by a dissolution/reprecipitation mechanism. The complete interpretations of Fe-57 Mossbauer and FT-IR spectra were given. TEM observation showed that the particle size and morphology of the oxide phases were very dependent on the experimental parameters.
Beta-feooh; Structural-properties; Hematite particles; Infrared-spectrum; Akaganeite; Transformation; Hydrolysis; Ions; Goethite
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Podaci o izdanju
278 (1-2)
1998.
291-301
objavljeno
0925-8388
10.1016/S0925-8388(98)00636-7