Reducing Size-Dispersion in One-Pot Aqueous Synthesis of Maghemite Nanoparticles

Abstract

Nanosized maghemite-like particles with reduced size-distribution were obtained using a one-pot synthesis route in aqueous medium. Forced hydrolysis of iron ions in ammoniac solution led to the formation of magnetite nanoparticles that were oxidized to maghemite in a hydrothermal digestion step that reduced the polydispersity of nanograins. The prepared nanoparticles were characterized by chemical analysis, X-ray diffractometry, magnetization, Raman spectroscopy and transmission electron microscopy measurements. Data showed that 14 nm-sized particles with polydispersity of about 0.14 were produced and, differently from other procedures, neither additional steps nor toxic reagents were needed to reduce size-dispersion or to oxidize magnetite to maghemite. These facts per se turn such nanodevice into a good potential choice for biomedical applications.

Luminescent and Magnetic Properties of Fe3O4@SiO2:phen:Eu3+

“…Magnetite nanoparticles were obtained by the coprecipitation of Fe 3+ (FeCl 3 .6H 2 O) and Fe 2+ (FeSO 4 .7H 2 O) salts (molar ratio of 2:1) in an alkaline medium (pH = 11), using an adapted version of a procedure described elsewhere 25 . The overall reaction can be written as equation 1:…”

One-step synthesis of magnetic chitosan for controlled release of 5-hydroxytryptophan

“…When compared with the ASTM lattice parameters for cubic magnetite and maghemite, respectively, 0.8396 nm and 0.8347 nm, the intermediary value of lattice parameter determined for our sample (0.836 nm) indicated that magnetite was partially oxidized to maghemite (γ-Fe 2 O 3 ). This can be explained by the fact that preparations were carried out in air, an oxidizing environment, so that magnetite was partially converted to maghemite [14]. The other phase identified from XRD pattern on Fig.…”

Bio‐Based Hybrid Magnetic Latex Particles Containing Encapsulated γ ‐Fe2O3 by Miniemulsion Copolymerization of Soybean Oil‐Acrylated Methyl Ester and Styrene

“…Maghemite was obtained by the co‐precipitation method followed by chemical oxidation using concentrated HNO 3 . First, 125 mL of an acid solution containing Fe 2+ (0.09 mol L −1 ) and Fe 3+ (0,18 mol L −1 ) (Fe(II):Fe(III) stoichiometric ratio of 1:2 was prepared by dissolution of FeCl 2 and FeCl 3 in distilled water, then heating the solution to 60 °C.…”