The effect of small amounts of ruthenium on the formation of magnetite in highly alkaline media was investigated using X-ray powder diffraction (XRD), Mössbauer and FT-IR spectroscopies, field emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Acicular a-FeOOH particles precipitated in a highly alkaline medium with the addition of tetramethylammonium ...

A brackish lagoon at Itaipu, Brazil, contains magnetotactic bacteria with unusually large magnetite magnetosomes (lengths 100-200 nm). The micromagnetic structures of the magnetosomes from two different coccoid organisms from the lagoon have been determinedby electron holography.The results are consistentwith single-magnetic-domain structure in the elongated magnetosomes from one organism and m...

The degradation of methyl tert-butyl ether (MTBE) was investigated in the aqueous solution of coated ZnO onto magnetite nanoparticale based on an advanced photocatalytic oxidation process. The photocatalysts were synthesized by coating of ZnO onto magnetite using precipitation method. The sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibration samp...

We successfully immobilized metalloporphyrins (MeP) in mesoporous silica coating magnetite spheres. In this sense, we prepared two different classes of core@shell supports, which comprise aligned (Fe3O4-AM-MeP, MeP=FeP or MnP) and non-aligned (Fe3O4-NM-MeP, MeP=FeP or MnP) mesoporous magnetic structures. X-ray diffractometry and energy dispersive X-ray spectroscopy confirmed the mesoporous natu...

Oxidation of iron (Fe) by oxygen (O2) at low pressures was investigated using XP spectra and QUASES TM Analyze and Generate software programs. The results indicated that the oxide films produced after short oxygen exposure times contained a mixture of magnetite (Fe3O4) and maghemite (c-Fe2O3) without distinct interfaces between the two being seen. Further investigation suggested that a reaction...

This study investigated heat transfer in magnetohydrodynamic (MHD) mixed convection flow of ferrofluid along a vertical channel. The channel with non-uniform wall temperatures was taken in a vertical direction with transverse magnetic field. Water with nanoparticles of magnetite (Fe3O4) was selected as a conventional base fluid. In addition, non-magnetic (Al2O3) aluminium oxide nanoparticles we...

Two biodegradable quaternary ammonium salts were synthesized and used as cationic collectors in processing iron ores by froth flotation. The flotation behaviors of iron minerals with the new biodegradable quaternary ammonium collectors were investigated by micro-flotation tests of quartz (SiO2) and magnetite (Fe3O4). It was observed that the new biodegradable collectors were effective in separa...

Abnormal accumulation of brain metals is a key feature of Alzheimer's disease (AD). Formation of amyloid-β plaque cores (APC) is related to interactions with biometals, especially Fe, Cu and Zn, but their particular structural associations and roles remain unclear. Using an integrative set of advanced transmission electron microscopy (TEM) techniques, including spherical aberration-corrected sc...

We report the preparation and characterization of spherical core-shell structured Fe3O4-Au magnetic nanoparticles, modified with two component self-assembled monolayers (SAMs) consisting of 3-mercaptophenylboronic acid (3-MBA) and 1-decanethiol (1-DT). The rapid and room temperature synthesis of magnetic nanoparticles was achieved using the hydroxylamine reduction of HAuCl4 on the surface of et...

Magnetotactic bacteria (MTB) synthesize magnetosomes composed of membrane-enveloped magnetite (Fe3O4) or greigite (Fe3S4) particles in the cells. Recently, several studies have shown some possibilities of controlling the biomineralization process and altering the magnetic properties of magnetosomes by adding some transition metals to the culture media under various environmental conditions. Her...