engleski

Influence of copper ions on the precipitation of goethite and hematite in highly alkaline media

The effects of Cu-dopant on the precipitation of alpha-FeOOH and alpha-Fe2O3 particles in highly alkaline media were investigated using 57Fe Mossbauer and Fourier transform infrared (FT-IR) spectroscopies and thermal field emission scanning electron microscopy (FE SEM). Only alpha-(Fe, Cu)OOH solid solutions were obtained between r = 0.0099 and 0.0291, where r = [Cu]/([Cu] + [Fe]). A mixture of alpha-(Fe, Cu)OOH and alpha-(Fe, Cu)2O3 solid solutions was obtained between r = 0.0385 and 0.0566, whereas only an alpha-(Fe, Cu)2O3 solid solution was obtained between r = 0.0698 and 0.1666. Cu-substitutions in alpha-(Fe, Cu)OOH and alpha-(Fe, Cu)2O3 decreased the hyperfine magnetic field values. With increased Cu-substitution in an alpha-FeOOH type structure the IR shifts were observed. With an increased r value of initial solution a gradual elongation of alpha-(Fe, Cu)OOH particles along the crystallographic c-axis was observed. At r = 0.0476, some alpha- (Fe, Cu)OOH particles were 700 nm long, and correspondingly the width and thickness of these particles decreased markedly. With a further increase in r the length of alpha-(Fe, Cu)OOH particles decreased. alpha-(Fe, Cu)2O3 particles showed varying sizes in dependence on the precipitation conditions, whereas their geometrical shapes matched those typical of alpha-Fe2O3.

alpha-FeOOH ; alpha-Fe2O3 ; 57Fe Mossbauer ; FT-IR ; FE SEM

Rad je kao poster prezentiran na skupu XXVIII European Congress on Molecular Spectroscopy, održanom od 3.-8.9.2006., Istanbul, Turska, objavljen u Knjizi sažetaka, 2006. ; Sevim Akyüz, Elif Akalın (ur.) ; str. 79-79. A Collection of Papers Presented at the XXVIIIth European Congress on Molecular Spectroscopy : Molecular spectroscopy and molecular structure 2006.