Resumo

PICASSO, Gino; VEGA, Jaime; UZURIAGA, Rosario  e  RUIZ, Gean Pieer. Synthesis of nanoparticles of magnetite by sol-gel and precipitation methods: study of chemical composition and structure. Rev. Soc. Quím. Perú [online]. 2012, vol.78, n.3, pp.170-182. ISSN 1810-634X.

In this work, nanoparticles based on magnetite have been prepared by sol-gel and precipitation methods. In the first case two variants have been applied: by growing of sol starting from nitrate precursor and ethylene glycol as dissolvent and to control the reduction process and force hydrolysis and steric control prepared from ferrum sulfate precursor and sodium citrate. In the second case the starting material was sulfate precursor, amonium hydroxide as precipitaing agent and ethylene glycol as surfactant. The samples have been characterized by X-ray diffraction technique (XRD), adsorption-desorption of N2 (BET equation model) and Mössbauer spectroscopy. XRD patterns of all samples showed typical peaks of magnetite which were detected in the following positions: 30,06 º, 35,42 º, 62,55 º. Average specific surface quantified by BET method was ranging from 40 to 50 m²/g with isotherm type IV corresponding to mesoporous surface. Mössbauer spectra of sample prepared from sol-gel (gel growing) carried out at home temperature detected the presence of 2 sextets consisting in 2 type of sites: first one due to octaedric positions (Fe²⁺, Fe³⁺) and the second one due to tetraedric positions (Fe³⁺). Grain size of magnetite samples, evaluated by Scherrer equation and specific surface area, was ranging from 2 to 20 nm.

Palavras-chave : Nanoparticles of magnetite; sol-gel; precipitation.

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