Exploring the Substitution of Fe(III) by Gd(III) in Nanomagnetite.

A promising superparamagnetic nanomagnetite dipped with Gd was synthesized for possible medical applications. Its size and morphology are independent of Gd content ranging from 1 to 5%. Gadolinium (III) replaced Fe(III) in the lattice.

Magnetic anisotropy engineering in onion-structured metal oxide nanoparticles combining dual exchange coupling and proximity effects.

A series of exchange-coupled magnetic nanoparticles combining several magnetic phases in an onion-type structure were synthesized by performing a three-step seed-mediated growth process. Iron and cobalt precursors were alternatively decomposed in high-boiling-temperature solvents (288-310 °C) to successively grow CoO and FeO shells (the latter in three stages) on the surface of FeO seeds. The structure and chemical composition of these nanoparticles were investigated in depth by combining a wide panel of advanced techniques, such as scanning transmission electron microscopy (STEM), electron energy-loss spectroscopy-spectrum imaging (EELS-SI), Fe Mössbauer spectrometry, and X-ray circular magnetic dichroism (XMCD) techniques.

A Microporous Multi-Cage Metal-Organic Framework for an Effective One-Step Separation of Branched Alkanes Feeds.

The improvement of the Total Isomerization Process (TIP) for the production of high-quality gasoline with the ultimate goal of reaching a Research Octane Number (RON) higher than 92 requires the use of specific sorbents to separate pentane and hexane isomers into classes of linear, mono- and di-branched isomers. Herein we report the design of a new multi-cage microporous Fe(III)-MOF (referred to as MIP-214, MIP stands for materials of the Institute of Porous Materials of Paris) with a flu-e topology, incorporating an asymmetric heterofunctional ditopic ligand, 4-pyrazolecarboxylic acid, that exhibits an appropriate microporous structure for a thermodynamic-controlled separation of hydrocarbon isomers. This MOF produced via a direct, scalable, and mild synthesis route was proven to encompass a unique separation of C5/C6 isomers by classes of low RON over high RON alkanes with a sorption hierarchy: (n-hexane≫n-pentane≈2-methylpentane>3-methylpentane)≫(2,3-dimethylbutane≈i-pentane≈2,2-dimethylbutane) following the adsorption enthalpy sequence.

Oxidation State and Structure of Fe in Nontronite: From Oxidizing to Reducing Conditions.

The redox reaction between natural Fe-containing clay minerals and its sorbates is a fundamental process controlling the cycles of many elements such as carbon, nutrients, redox-sensitive metals, and metalloids (e.g., Co, Mn, As, Se), and inorganic as well as organic pollutants in Earth's critical zone.

Immobilisation of contaminants by 'green'-synthesized magnetite as a remediation approach to the phosphogypsum waste leachates model solution.

Contaminant removal from (waste)waters by magnetite is a promising technology. In the present experimental study, a magnetite recycled from the steel industry waste (zero-valent iron powder) was used to investigate the sorption of As, Sb and U in phosphate-free and -rich suspensions, i.e.

Hierarchical superparamagnetic metal-organic framework nanovectors as anti-inflammatory nanomedicines.

Among a plethora of drug nanocarriers, biocompatible nanoscale metal-organic frameworks (nanoMOFs) with a large surface area and an amphiphilic internal microenvironment have emerged as promising drug delivery platforms, mainly for cancer therapy. However, their application in biomedicine still suffers from shortcomings such as a limited chemical and/or colloidal stability and/or toxicity. Here, we report the design of a hierarchically porous nano-object (denoted as USPIO@MIL) combining a benchmark nanoMOF (that is, MIL-100(Fe)) and ultra-small superparamagnetic iron oxide (USPIO) nanoparticles (that is, maghemite) that is synthesized through a one-pot, cost-effective and environmentally friendly protocol.

Influence of Nd Substitution on the Phase Constitution in (Zr,Ce)FeSi Alloys with the ThMn Structure.

Iron-based compounds with a ThMn-type structure have the potential to bridge the gap between ferrites and high performance NdFeB magnets. From the point of view of possible applications, the main advantage is their composition, with about 10 wt.% less rare earth elements in comparison with the 2:14:1 phase.

Two-step single-reactor synthesis of oleic acid- or undecylenic acid-stabilized magnetic nanoparticles by thermal decomposition.

Different iron oxides (i.e., magnetite, maghemite, goethite, wüstite), particularly nanosized particles, show distinct effects on living organisms.

Presence of Induced Weak Ferromagnetism in Fe-Substituted YFeCrO Crystalline Compounds.

Fe-substituted YFeCrO crystalline compounds show promising magnetic and multiferroic properties. Here we report the synthesis and characterization of several compositions from this series. Using the autocombustion route, various compositions (x = 0.

Selenium Nanowire Formation by Reacting Selenate with Magnetite.

The mobility of Se, a fission product of U and long-lived radioisotope, is an important parameter in the safety assessment of radioactive nuclear waste disposal systems. Nonradioactive selenium is also an important contaminant of drainage waters from black shale mountains and coal mines. Highly mobile and soluble in its high oxidation states, selenate (Se()O) and selenite (Se()O) oxyanions can interact with magnetite, a mineral present in anoxic natural environments and in steel corrosion products, thereby being reduced and consequently immobilized by forming low-solubility solids.

Deciphering the Thermal and Electrochemical Behaviors of Dual Redox-Active Iron Croconate Violet Coordination Complexes.

Interest in coordination compounds based on non-innocent ligands (NILs) for electrochemical energy storage has risen in the last few years. We have focused our attention on an overlooked redox active linker, croconate violet, which has not yet been addressed in this field although closely related to standard NILs such as catecholate and tetracyanoquinodimethane. Two anionic complexes consisting of Fe(II) and croconate violet (-2) with balancing potassium cations were isolated and structurally characterized.

A Comprehensive Study of Pristine and Calcined f-MWCNTs Functionalized by Nitrogen-Containing Functional Groups.

We present the study of pristine and calcined f-MWCNTs functionalized by nitrogen-containing functional groups. We focus on the structural and microstructural modification tuned by the previous annealing. However, our primary goal was to analyze the electronic structure and magnetic properties in relation to the structural properties using a multi-technique approach.

Structure-Property-Function Relationships of Iron Oxide Multicore Nanoflowers in Magnetic Hyperthermia and Photothermia.

Magnetite and maghemite multicore nanoflowers (NFs) synthesized using the modified polyol-mediated routes are to date among the most effective nanoheaters in magnetic hyperthermia (MHT). Recently, magnetite NFs have also shown high photothermal (PT) performances in the most desired second near-infrared (NIR-II) biological window, making them attractive in the field of nanoparticle-activated thermal therapies. However, what makes magnetic NFs efficient heating agents in both modalities still remains an open question.

Unveiling the role of surface, size, shape and defects of iron oxide nanoparticles for theranostic applications.

Iron oxide nanoparticles (IONPs) are well-known contrast agents for MRI for a wide range of sizes and shapes. Their use as theranostic agents requires a better understanding of their magnetic hyperthermia properties and also the design of a biocompatible coating ensuring their stealth and a good biodistribution to allow targeting of specific diseases. Here, biocompatible IONPs of two different shapes (spherical and octopod) were designed and tested and to evaluate their abilities as high-end theranostic agents.

Iron Stearate Structures: An Original Tool for Nanoparticles Design.

Iron carboxylates are widely used as iron precursors in the thermal decomposition process or considered as in situ formed intermediate precursors. Their molecular and three-dimensional (3D)-structural nature has been shown to affect the shape, size, and composition of the resulting iron oxide nanoparticles (NPs). Among carboxylate precursors, stearates are particularly attractive because of their higher stability to aging and hydration and they are used as additives in many applications.

A Detailed Investigation of the Onion Structure of Exchanged Coupled Magnetic FeO@CoFeO@FeO Nanoparticles.

Nanoparticles that combine several magnetic phases offer wide perspectives for cutting edge applications because of the high modularity of their magnetic properties. Besides the addition of the magnetic characteristics intrinsic to each phase, the interface that results from core-shell and, further, from onion structures leads to synergistic properties such as magnetic exchange coupling. Such a phenomenon is of high interest to overcome the superparamagnetic limit of iron oxide nanoparticles which hampers potential applications such as data storage or sensors.

Influence of Silica Coatings on Magnetite-Catalyzed Selenium Reduction.

The reactivity of iron(II/III) oxide surfaces may be influenced by their interaction with silica, which is ubiquitous in aquatic systems. Understanding the structure-reactivity relationships of Si-coated mineral surfaces is necessary to describe the complex surface behavior of nanoscale iron oxides. Here, we use Si-adsorption isotherms and Fourier transform infrared spectroscopy to analyze the sorption and polymerization of silica on slightly oxidized magnetite nanoparticles (15% maghemite and 85% magnetite, i.

Removal of As, As, Sb, and Hg ions from aqueous solutions by pure and co-precipitated akaganeite nanoparticles: adsorption kinetics studies.

Adsorption kinetics models have been used to evaluate the adsorption behaviour of pollutants on different materials but there are no reports for the adsorption of As, As, Sb and Hg on co-precipitated akaganeite nanoparticles which were previously formed in the presence of these ions. In this research, the performance of pure and co-precipitated akaganeite nanoparticles as adsorbents of As, As, Sb and Hg in aqueous solutions was evaluated using the nonlinear kinetics models of Langmuir, Lagergren, Ho-McKay, Bangham, Elovich and simplified Elovich. In addition, transmission Fe Mössbauer spectrometry was used for the first time to compare the physico-chemical properties of akaganeite before and after the adsorption processes.

Rheological, Microstructural and Thermal Properties of Magnetic Poly(Ethylene Oxide)/Iron Oxide Nanocomposite Hydrogels Synthesized Using a One-Step Gamma-Irradiation Method.

Magnetic polymer gels are a new promising class of nanocomposite gels. In this work, magnetic PEO/iron oxide nanocomposite hydrogels were synthesized using the one-step -irradiation method starting from poly(ethylene oxide) (PEO) and iron(III) precursor alkaline aqueous suspensions followed by simultaneous crosslinking of PEO chains and reduction of Fe(III) precursor. -irradiation dose and concentrations of Fe, 2-propanol and PEO in the initial suspensions were varied and optimized.

Stabilization of a mixed iron vanadium based hexagonal tungsten bronze hydroxyfluoride HTB-(FeV)F(OH) as a positive electrode for lithium-ion batteries.

In our search for novel insertion compounds for Li-based batteries, we have identified a new mixed iron vanadium based Hexagonal Tungsten Bronze (HTB) type phase. Its synthesis involves two steps which consist first of preparing mixed metal hydrated fluoride Fe1.64V1.

Synthesis of Magnetic Wires from Polyol-Derived Fe-Glycolate Wires.

Fe-glycolate wires with micrometer-scale lengths can be synthesized by the polyol process. Although the as-produced wires are in the paramagnetic state at room temperature, they are transformed into ferrimagnetic iron oxides and ferromagnetic metallic iron wires by reductive annealing. The shape of the wires is unchanged by reductive annealing, and it is possible to control the magnetic properties of the resulting wire-shaped ferri/ferromagnets by adjusting the annealing conditions.

On the first evidence of exchange-bias feature in magnetically contrasted consolidates made from CoFeO-CoO core-shell nanoparticles.

Hetero-nanostructures based on magnetic contrast oxides have been prepared as highly dense nanoconsolidates. Cobalt ferrite-cobalt oxide core-shell type nanoparticles (NPs) were synthesized by seed mediated growth in polyol and subsequently consolidated by Spark Plasma Sintering (SPS) at 500 °C for a few minutes while applying a uniaxial pressure of 100 MPa. It is interesting to note that the exchange bias feature observed in the core-shell NPs is reproduced in their ceramic counterparts, or even attenuated.