Structure and superparamagnetic behaviour of magnetite nanoparticles in cellulose beads |
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Authors: | José R. Correa,Eduardo Bordallo,Vivian Leó n,Carlos Negro,Regino Sá ez-Puche |
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Affiliation: | a Department of General Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400, Cuba b Sugar Cane-Cellulose Research Center, Cuba-9, Quivicán, Cuba c Department of Inorganic Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400, Cuba d Department of Inorganic Chemistry-1, Complutense University of Madrid, Madrid 28040, Spain e Chemical Engineering Department, Complutense University of Madrid, Madrid 28040, Spain f Electron Microscopy Center, Complutense University of Madrid, Madrid 28040, Spain |
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Abstract: | Superparamagnetic magnetite nanoparticles were obtained starting from a mixture of iron(II) and iron(III) solutions in a preset total iron concentration from 0.04 to 0.8 mol l−1 with ammonia at 25 and 70 °C. The regeneration of cellulose from viscose produces micrometrical spherical cellulose beads in which synthetic magnetite were embedded. The characterization of cellulose-magnetite beads by X-ray diffraction, Scanning and Transmission Electron Microscopy and magnetic measurement is reported. X-ray diffraction patterns indicate that the higher is the total iron concentration and temperature the higher is the crystal size of the magnetite obtained. Transmission Electron Microscopy studies of cellulose-magnetite beads revealed the distribution of magnetite nanoparticles inside pores of hundred nanometers. Magnetite as well as the cellulose-magnetite composites exhibit superparamagnetic characteristics. Field cooling and zero field cooling magnetic susceptibility measurements confirm the superparamagnetic behaviour and the blocking temperature for the magnetite with a mean size of 12.5 nm, which is 200 K. |
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Keywords: | A. Composites A. Magnetic materials B. Chemical synthesis C. Electron microscopy D. Magnetic properties |
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