Structural characterization of Akaganeite using synchrotron X-ray radiation

VILLABA J.; BEREZOSKI S. ; FAUCE J.; LIMANDRI S.; GALVAN V.

Bariloche

Encuentro; VII Reunión Anual de la Sociedad Argentina de Cristalografía; 2011

Sociedad Argentina de Cristalografía

Iron oxide particles have gained increasing interest in the field of nanoscience and nanotechnology, due to its particular physical and chemical properties. These properties depend on particle size (quantum effects), morphology and engineering shape (thin films, nanocrystals, self-assembled, ferrofluids, etc) [1]. Nowadays, iron oxides are applied in pigments industry, magnetic devises, anticorrosive materials, catalysis agents and residual water treatment [2,3,4,5,6]. Akaganeite was precipitated by the thermohydrolysis of a FeCl3.6H2O solution (0.1 mol/L) at 90 C for 48 h. After this period, a yellow-brown colloidal material was formed. The mixture was carefully decanted in order to remove the excess of FeCl3. The colloidal material was dispersed in water, and washed with ultra-pure water through decantation until the pH was constant. This is a variation of the method suggested by Schwertmann [7]. Structural parameters, purity and crystallite mean size of the samples were obtained from de X-ray powder diffraction spectra by means of the Rietveld method. The spectra were acquired by X-ray synchrotron radiation excitation. The main advantages of a synchrotron source are its high brilliance (higher flux of photons), very low spectral dispersion, small vertical divergence and higher energy (smaller radiation length). As a result, absorption effects are minimized, minor phases are made visible and the improved resolution reduce correlations between parameters, and improve the accuracy of the results. [1] J. Rodriguez-Carvajal, Physica B, 192 (1993), 55. [2] C.J. Smithells, Metals Reference Book, 5ª ed. Butterworths, Oxford, 1976, p. 66. [1] I. Duraes, Materials Letters, 59 (2005) 859. [2] N. Bourlinos et al., Chem. Mater., 14 (2002) 3226. [3] Y. Xiong, Inorganic Chem., 43 (2004) 6540. [4] K. Plantier, Combustion and Flame, 140 (2005), 299. [5] W. Dai, J. Colloid Interface Sci., 288 (2005), 298. [6] S, Samanta, J. Magn. Magn. Mat., 285(2005), 296 [7] U. Schwertmann, R.M. Cornell, The Iron Oxides in the Laboratory, Preparation and Characterization, Wiley, Weinheim Germany, 2000.