Structural study of a series of synthetic goethites obtained in aqueous solutions containing cadmium(II) ions
Carregando...
Data
2003-03-01
Autores
Sileo, E. E.
Solis, P. S.
Paiva-Santos, C. O.
Título da Revista
ISSN da Revista
Título de Volume
Editor
J C P D S-int Centre Diffraction Data
Resumo
The capacity of goethite for Cd-II substitution has been explored in a series of synthetic samples prepared from Fe-III and Cd-II nitrate solutions aged 21 days in alkaline media. The total metal content ([ Fe] + [ Cd]) was 0.071 M in all preparations. The samples have been characterized by chemical and X-ray diffraction analysis; the morphology of the solids is described. The cell parameters for all samples were obtained by the Rietveld fits to the X-ray diffraction data. Refined structures show that for samples prepared at the final molar ratio mu(Cd)less than or equal to5.50 (expressed as mu(Cd) = 100X[Cd]/[Cd] + [Fe]), a (Cd, Fe)-goethite is the only crystalline product. In these samples, the unit cell parameters increased as a function of Cd concentration, indicating Cd incorporation in the structural frame. At the preparative ratio, mu(Cd)=7.03, the incorporation of Cd in the goethite structure is drastically reduced and a probable Cd-substituted hematite is formed together with the Fe,Cd-goethite. (C) 2003 International Centre for Diffraction Data.
Descrição
Palavras-chave
X-ray powder diffraction, Rietveld analysis, substituted goethite, cadmium, substituted hematite
Como citar
Powder Diffraction. Newtown Sq: J C P D S-int Centre Diffraction Data, v. 18, n. 1, p. 50-55, 2003.