The thermomagnetic behavior of remanence-induced magnetite (Fe3O4) particles in the pseudo-single-domain (PSD) size range (~0.1–10μm), which dominate the magnetic signature of many rock lithologies, is investigated using off-axis electron holography. Construction of magnetic induction maps allowed for the visualization of the vortex domain state in an individual Fe3O4 grain (~200 nm in diameter...

In the last decade, nanobiotechnology has evolved rapidly with an extensive impact on biomedical area. In order to improve bioavailability and minimize adverse effects, drug delivery systems based on magnetic nanocomposites are under development mainly for cancer imaging and antitumor therapy. In this regard, pH sensitive core-shell magnetic nanoparticles (NPs) with accurate controlled size and...

We report here a general synthetic strategy to encapsulate metal clusters within zeolites during their hydrothermal crystallization. Precursors to metal clusters are stabilized against their premature colloidal precipitation as hydroxides during zeolite crystallization using bifunctional (3-mercaptopropyl)trimethoxysilane ligands. Mercapto (-SH) groups in these ligands interact with cationic me...

The use and application of synthetic zeolites for ion exchange, adsorption and catalysis has shown enormous potential in industry. In this study, X-ray fluorescence (XRF) analysis was used to determine Si and Al in fly ash (FA) precipitates. The Si and Al contents of the fly ash precipitates were used as indices for the alkaline hydrothermal conversion of the fly ash compounds into zeolites. Pr...

In this research, the magnetic Fe3O4/zeolite NaA nanocomposite (Fe3O4/ZA), Fe3O4 nanoparticles, and zeolite have been synthesized by facile hydrothermal methods for adsorption removal of methylene blue from aqueous solution. The as-synthesized Fe3O4/ZA was characterized X-ray diffraction (XRD), MicroRaman analysis, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SE...

A new facile coating strategy based on the hydrophobicity of methyl groups was developed to prevent nano-sized magnetite particles from strong acid corrosion. In this method, three steps of hydrolysis led to three layers of protection shell coating Fe3O4 nanoparticles. Filled with hydrophobic methyl groups, the middle layer mainly prevented the magnetic core from strong acid corrosion. These ma...

We report the synthesis of Fe3O4@mSiO2 nanostructures of different meso-silica (mSiO2) shell thickness, their biocompatibility and behaviors for loading and release of a model drug ibuprofen. The composite nanostructures have superparamagnetic magnetite cores of 208 nm average size and meso-silica shells of 15 to 40 nm thickness. A modified Stöber method was used to grow the meso-silica shells ...

Stable hydrophobic nanocomposites of magnetic nanoparticles and clay are prepared by the self-assembly of magnetite (Fe3O4) nanoparticles on surfaces of exfoliated clay platelets. Due to the attractive interaction between hydrophobic groups, oleic acid coated nanoparticles are strongly attached to the surface of cetyl trimethylammonium cation coated clay platelets in organic media. Crystal stru...

An outstanding biophysical puzzle is focused on the apparent ability of weak, extremely low-frequency oscillating magnetic fields to enhance cryopreservation of many biological tissues. A recent theory holds that these weak magnetic fields could be inhibiting ice-crystal nucleation on the nanocrystals of biological magnetite (Fe3O4, an inverse cubic spinel) that are present in many plant and an...

Magnetic separations at very low magnetic field gradients (<100 tesla per meter) can now be applied to diverse problems, such as point-of-use water purification and the simultaneous separation of complex mixtures. High-surface area and monodisperse magnetite (Fe3O4) nanocrystals (NCs) were shown to respond to low fields in a size-dependent fashion. The particles apparently do not act independen...