Abstract: Chitosan-coated magnetic nanoparticles (CMNP) were obtained at 70 °C and 80 °C in a one-step method, which comprises precipitation in reverse microemulsion in the presence of low chitosan concentration in the aqueous phase. X-ray diffractometry showed that CMNP obtained at both temperatures contain a mixture of magnetite and maghemite nanoparticles with ≈4.5 nm in average diameter, determined by electron microscopy, which suggests that precipitation temperature does not affect the particle size. The chitosan coating on nanoparticles was inferred from Fourier transform infrared spectrometry measurements; furthermore, the carbon concentration in the nanoparticles allowed an estimation of chitosan content in CMNP of 6%–7%. CMNP exhibit a superparamagnetic behavior with relatively high final magnetization values (≈49–53 emu/g) at 20 kOe and room temperature, probably due to a higher magnetite content in the mixture of magnetic nanoparticles. In addition, a slight direct effect of precipitation temperature on magnetization was identified, which was ascribed to a possible higher degree of nanoparticles crystallinity as temperature at which they are obtained increases. Tested for Pb2+ removal from a Pb(NO3)2 aqueous solution, CMNP showed a recovery efficacy of 100%, which makes them attractive for using in heavy metals ion removal from waste water.
Keywords: chitosan magnetic nanoparticles; one-step microemulsion precipitation; chitosan low content
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López, R.G.; Pineda, M.G.; Hurtado, G.; León, R.D.; Fernández, S.; Saade, H.; Bueno, D. Chitosan-Coated Magnetic Nanoparticles Prepared in One Step by Reverse Microemulsion Precipitation. Int. J. Mol. Sci. 2013, 14, 19636-19650.
López RG, Pineda MG, Hurtado G, León RD, Fernández S, Saade H, Bueno D. Chitosan-Coated Magnetic Nanoparticles Prepared in One Step by Reverse Microemulsion Precipitation. International Journal of Molecular Sciences. 2013; 14(10):19636-19650.
López, Raúl G.; Pineda, María G.; Hurtado, Gilberto; León, Ramón D.; Fernández, Salvador; Saade, Hened; Bueno, Darío. 2013. "Chitosan-Coated Magnetic Nanoparticles Prepared in One Step by Reverse Microemulsion Precipitation." Int. J. Mol. Sci. 14, no. 10: 19636-19650.