Distinct morphological characteristics of magnetite formed intracellularly by magnetic bacteria (magnetosome) are invoked as compelling evidence for biological activity on Earth and possibly on Mars. Crystals of magnetite produced extracellularly by a variety of bacteria including Geobacter metallireducens GS-15, thermophilic bacteria, and psychrotolerant bacteria are, however, traditionally no...

Diatomite-supported/unsupported magnetite nanoparticles were prepared by co-precipitation and hydrosol methods, and characterized by X-ray diffraction, nitrogen adsorption, elemental analysis, differential scanning calorimetry, transmission electron microscopy and X-ray photoelectron spectroscopy. The average sizes of the unsupported and supported magnetite nanoparticles are around 25 and 15 nm...

Magnetite nanoparticles combined with polymers produce white-light emission under multiphoton laser irradiation. Understanding the photonic reaction in magnetite-polymer composites is critical for application of magnetite NPs as photothermal agents. Laser irradiated magnetite nanoparticle-poly(methyl methacrylate) (PMMA) composites exhibit fluorescence due to the carbon double-bond formation re...

Magnetotactic bacteria are characterized by the magnetosome, a membrane-bound, nano-sized organelle containing a magnetic crystal. This organelle is believed to help the bacteria to navigate along the geomagnetic field lines and find a preferred habitat for survival. The magnetosome is a biomineral structure highly controlled by the bacteria, composed of either magnetite (Fe3O4) or greigite (Fe...

The enhancement of the photocatalytic activity of TiO₂ nanoparticles (NPs), synthesized in the presence of a very small amount of magnetite (Fe₃O₄) nanoparticles, is here presented and discussed. From X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses, the crystallinity of TiO₂ nanoparticles (NPs) seems to be affected by Fe₃O₄, acting as nano-seeds to improve the tetra...

We report on the fabrication of thin coatings based on polylactic acid-chitosan-magnetite-eugenol (PLA-CS-Fe3O4@EUG) nanospheres by matrix assisted pulsed laser evaporation (MAPLE). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) investigation proved that the homogenous Fe3O4@EUG nanoparticles have an average diameter of about 7 nm, while the PLA-CS-Fe3O4@EUG nanos...

The suitability of magnetic nanoparticles (MNPs) to act as heat nano-sources by application of an alternating magnetic field has recently been studied due to their promising applications in biomedicine. The understanding of the magnetic relaxation mechanism in biocompatible nanoparticle systems is crucial in order to optimize the magnetic properties and maximize the specific absorption rate (SA...

The contamination of sulfur emanating from pyrrhotite in magnetite concentrates has been a problem in iron ore processing. This study utilized froth flotation to float pyrrhotite away from magnetite using collectors of xanthate and dixanthogen. It was found that xanthate or dixanthogen alone could not achieve selective separation between pyrrhotite and magnetite in flotation. A high loss of mag...