ChemInform Abstract: Synthesis of Highly Crystalline and Monodisperse Maghemite Nanocrystallites Without a Size-Selection Process.
ABSTRACT The synthesis of highly crystalline and monodisperse gamma-Fe(2)O(3) nanocrystallites is reported. High-temperature (300 degrees C) aging of iron-oleic acid metal complex, which was prepared by the thermal decomposition of iron pentacarbonyl in the presence of oleic acid at 100 degrees C, was found to generate monodisperse iron nanoparticles. The resulting iron nanoparticles were transformed to monodisperse gamma-Fe(2)O(3) nanocrystallites by controlled oxidation by using trimethylamine oxide as a mild oxidant. Particle size can be varied from 4 to 16 nm by controlling the experimental parameters. Transmission electron microscopic images of the particles showed 2-dimensional and 3-dimensional assembly of particles, demonstrating the uniformity of these nanoparticles. Electron diffraction, X-ray diffraction, and high-resolution transmission electron microscopic (TEM) images of the nanoparticles showed the highly crystalline nature of the gamma-Fe(2)O(3) structures. Monodisperse gamma-Fe(2)O(3) nanocrystallites with a particle size of 13 nm also can be generated from the direct oxidation of iron pentacarbonyl in the presence of oleic acid with trimethylamine oxide as an oxidant.
Full-textDOI: · Available from: Hyon Bin Na, Feb 18, 2014
SourceAvailable from: Congren Yang
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ABSTRACT: A novel composite material for the efficient separation of oil from water is presented. It is based on polyurethane (PU) foams modified with colloidal superparamagnetic iron oxide nanoparticles (NPs) in their whole volume and sub-micrometer polytetrafluoroethylene (PTFE) particles on their surface. The hydrophobic and oleophobic original foam becomes water-repellent and oil-absorbing due to the presence of the PTFE particles on its surface. The oil absorption rate is significantly increased by the presence of the colloidal iron oxide NPs. Detailed analysis demonstrates that the NP capping molecules play a significant role in the oil absorption mechanism. Furthermore, the treated foams can be magnetically actuated, and be moved towards oil polluted waters by a weak magnet. As a result, they can absorb the oil contaminants from the water surface, purifying it.Advances in Science and Technology 09/2012; 77:159-164. DOI:10.4028/www.scientific.net/AST.77.159
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ABSTRACT: Magnetic iron oxide nanoparticles (MNPs) have emerged as highly desirable nanomaterials in the context of many research works, due to their extensive industrial applications. However, they are prone to agglomerate on account of the anisotropic dipolar attraction, and therefore misled the particular properties related to single-domain magnetic nanostructures. The surface modification of MNPs is quite challenging for many applications, as it involves surfactant-coating for steric stability, or surface modifications that results in repulsive electrostatic force. Hereby, we focus on the dispersion of MNPs and colloidal stability.Colloids and surfaces B: Biointerfaces 02/2015; DOI:10.1016/j.colsurfb.2015.02.003 · 4.29 Impact Factor