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Controlled spatial arrangements of superparamagnetic iron oxide nanoparticles (SPIONs) in complex nanostructures determine fine tuning of physico-chemical properties which, in turn, may lead to new practical applications. We report here on newly observed properties of hierarchical SPIONs nanostructure with bundle-like morphology, also known as nanobundles. Colloidal chemical processes and sol-gel synthesis were used for the synthesis of nanobundles, i.e. i) self-assembly of SPIONs into magnetic nanoparticle clusters, ii) their magnetic assembly to the nanochains, and finally iii) formation of bundle-like hierarchical nanostructure. An XRPD measurements show spinel crystal structure of maghemite/magnetite nanoparticles, EDS analysis reveals Fe, Si and O as main elements whereas SEM/TEM analysis show silica-coated magnetic nanoclusters (∼100 nm) and their hierarchical assemblies with bundle-like morphology of ∼8 μm length and ∼1 μm width. TEM analysis revealed core-shell nature of iron oxide nanoparticle clusters with their size of around 80 nm that were coated by an amorphous silica shell with thickness of ∼15 nm. The nanoclusters in the core are constructed of maghemite/magnetite nanoparticle assembly with primary iron oxide nanoparticle size about 10 nm. The magnetization M data as a function of an applied external magnetic field H were successfully fitted by the Langevin function, whence the magnetic moment μ p = 19256 μ B , and the diameter d = 9.6 nm of nanoparticles were determined. Microsized bundle-like particles are superparamagnetic, magnetically guidable and possess high transverse relaxivity of r 2 = 397.8 mM−1s−1. Magnetic properties and such high value of transverse relaxivity holds promise for nanobundles application in MRI imaging (MRI contrast agent), as nanobundles may enhance the magnetic field in their surroundings and enhance proton relaxation processes. Our nanobundles can open new opportunities in the biomedical applications, magnetic separation, photonic crystals and magnetic liquid manipulation and can be inspiration for synthesizing novel self-assembled nanoparticle structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • In situ iron oxide nanoparticles were synthesized into heavy crude oil. • Magnetite and akaganeite nanoparticles in situ presented sizes of 20–43 nm. • Reaction conditions were at 200 nm3/m3 of H 2 /heavy crude oil ratio, 380 °C and 1 h. • Residue conversion was approximately 20 %. • Spent catalyst showed the iron sulfide phase, although no presulfiding was realized. We proposed a direct in situ synthesis method for iron oxide nanoparticles (NPs) along with catalytic erformance upgrading of heavy crude oil (HCO). Our method compares the upgrading of a HCO where other iron oxide nanoparticles were synthesized by a traditional thermal decomposition method of organometallic compounds in the presence of stabilizing agents and solvents of high boiling points. Furthermore, the in situ nanoparticles were extensively characterized by XRD, Mössbauer spectroscopy and TEM microscopy which confirmed the presence of magnetite and akaganeite phases, with an average diameter of 20−43 nm. Nanoparticles by thermal decomposition method were investigated by XRD, UHR-FE-SEM and HRTEM and showed the formation of magnetite nanoparticles with an average diameter of 6.7 ± 1.4 nm. Subsequently, the nanoparticles were evaluated in a batch reactor using HCO from the Golden Lane of Mexico at 44.1 bar (initial H 2 pressure) and 380 °C, for 1 h at 500 rpm. It was observed that, even under hydrogen limited conditions, there are better physicochemical properties in terms of viscosity, API gravity and heavy fractions decrease, for example, the residue conversion was about 20 % and the kinetic model was adjusted to a five lump model. The formation of the iron sulfide phase (FeS) was detected during the analysis of the spent catalyst. [ABSTRACT FROM AUTHOR]

DNA-binding protein from starved cells (Dps) takes a special place among dodecamer mini-ferritins. Its most important function is protection of bacterial genome from various types of destructive external factors via in cellulo Dps–DNA co-crystallization. This protective response results in the emergence of bacterial resistance to antibiotics and other drugs. The protective properties of Dps have attracted a significant attention of researchers. However, Dps has another equally important functional role. Being a ferritin-like protein, Dps acts as an iron depot and protects bacterial cells from the oxidative damage initiated by the excess of iron. Here we investigated formation of iron oxide nanoparticles in the internal cavity of the Dps dodecamer. We used anomalous small-angle X-ray scattering as the main research technique, which allows to examine the structure of metal-containing biological macromolecules and to analyze the size distribution of metal nanoparticles formed in them. The contributions of protein and metal components to total scattering were distinguished by varying the energy of the incident X-ray radiation near the edge of the metal atom absorption band (the K-band for iron). We examined Dps specimens containing 50, 500, and 2000 iron atoms per protein dodecamer. Analysis of the particle size distribution showed that, depending on the iron content in the solution, the size of the nanoparticles formed inside the protein molecule was 2 to 4 nm and the growth of metal nanoparticles was limited by the size of the protein inner cavity. We also found some amount of iron ions in the Dps surface layer. This layer is very important for the protein to perform its protective functions, since the surface-located N-terminal domains determine the nature of interactions between Dps and DNA. In general, the results obtained in this work can be useful for the next step in studying the Dps phenomenon, as well as in creating biocompatible and solution-stabilized metal nanoparticles. [ABSTRACT FROM AUTHOR]

This paper presents structural evolution in iron oxide tablets at vibration testing for catalytic converters. The raw tablets composed from a mixture of cordierite powder with nanostructured iron oxide powders (pure and K-doped) and PVP binder. The analysis of the structural integrity of the raw tablets before vibration testing is evidenced by metallographic microscopic highlight the incidence of cracks. The raw tablets were mechanical vibration tested under normal operating conditions within the vibration damper to determine the structural integrity of the tablets. The mechanical vibration behavior of the tablets is essential in the development of new catalyst based on iron oxide nanoparticles for the reduction of gaseous pollutants from internal combustion engines. [ABSTRACT FROM AUTHOR]

Nanofluid-based direct absorption of solar heat results in thermal efficiencies superior to conventional solar thermal technology. In addition, convection of nanofluid can be sustained pump-free in the collector. In this article, we study an aqueous magnetic nanofluid capable to establish the photothermal convection in a lab-scale direct absorption solar collector equipped with a solenoid. The nanofluid consisted of 60-nm Fe 2 O 3 particles dispersed in distilled water at concentration in the range 0.5% wt.-2.0% wt. An empirical model of the photothermal convection was developed based on the experiments. The model accounted for magnetic and thermophoretic forces acting within the nanofluid. The nanofluid with up to 2.0% wt. iron oxide nanoparticles obtained the velocity of ∼ 5 mm/s under the magnetic field of up to 28 mT. This resulted in the maximum thermal efficiency of the collector equal to 65%. [Display omitted] • Nanofluid-based direct absorption solar collector is studied. • Nanofluid is produced with 0.5% and 2.0% of Fe 2 O 3 nanoparticles. • Magnetic field up to 28 mT is applied to nanofluid. • Photothermal convection is established in the fluid with the velocity of 2-5 mm/s. • Maximum thermal efficiency of the collector is 65%. [ABSTRACT FROM AUTHOR]

Background: Parkinson's disease (PD) is a debilitating disease that alters an individual's functionality. Parkinsonism is a complex symptom consisting of numerous motor and non-motor features, and although several disorders are responsible, PD remains the most important. Several theories have been proposed for the characteristic pathological changes, the most important of which is the loss of dopaminergic neurons associated with a reduced ability to perform voluntary movements. Many drugs have been developed over the years to treat the condition and prevent its progression, but drug delivery is still a challenge due to the blood–brain barrier, which prevents the passage of drugs into the central nervous system. However, with the advances in nanotechnology in the medical field, there is growing hope of overcoming this challenge. Summary: Our review highlights the potential role of three commonly studied nanoparticles in laboratory-induced animal models of PD: chitosan, PLGA, and iron oxide nanoparticles as potential PD therapy in humans. [ABSTRACT FROM AUTHOR]

Here, a sol‐gel method is used to prepare a Prussian blue analogue (NiFe‐PBA) precursor with a 2D network, which is further annealed to an Fe3O4/NiCx composite (NiFe‐PBA‐gel‐cal), inheriting the ultrahigh specific surface area of the parent structure. When the composite is used as both anode and cathode catalyst for overall water splitting, it requires low voltages of 1.57 and 1.66 V to provide a current density of 100 mA cm−2 in alkaline freshwater and simulated seawater, respectively, exhibiting no obvious attenuation over a 50 h test. Operando Raman spectroscopy and X‐ray photoelectron spectroscopy indicate that NiOOH2–x active species containing high‐valence Ni3+/Ni4+ are in situ generated from NiCx during the water oxidation. Density functional theory calculations combined with ligand field theory reveal that the role of high valence states of Ni is to trigger the production of localized O 2p electron holes, acting as electrophilic centers for the activation of redox reactions for oxygen evolution reaction. After hydrogen evolution reaction, a series of ex situ and in situ investigations indicate the reduction from Fe3+ to Fe2+ and the evolution of Ni(OH)2 are the origin of the high activity. [ABSTRACT FROM AUTHOR]

The surface chemistry of monoethanolamine (MEA) on oxide surfaces is investigated by Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy under different environmental conditions of pH, concentration, and ionic strength. [Display omitted] Chemical contaminants are becoming an increasingly greater concern for water quality and it is well known that interactions with geochemical interfaces impact the fate and transport of these contaminants in the environment. In this study, we investigated the interactions of one such chemical contaminant, monoethanolamine (MEA), with oxide surfaces, particularly titanium dioxide (TiO 2) and iron oxide (α-Fe 2 O 3). Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy was used to probe the adsorption behavior of MEA on titanium dioxide (TiO 2) and iron oxide (α-Fe 2 O 3) nanoparticles as a function of pH and other environmental conditions including concentration and ionic strength. Both the extent and initial rates of adsorption of MEA on these oxide surfaces increases with increasing pH. Adsorption on these oxide surfaces increases with solution concentration until saturation occurs and MEA adsorbs more readily at higher pH. Furthermore, adsorption decreases with increasing ionic strength, demonstrating the importance of electrostatic interactions to this process. Based on these results, a mechanistic picture emerges for the interaction of MEA with titanium dioxide and iron oxide across a range of pH values. Overall, this study provides important insights into the surface chemistry and interactions between an alkanolamine and geochemical oxide interfaces. [ABSTRACT FROM AUTHOR]

The majority of recent studies have focused on obtaining MRI materials for internal use. However, this study focuses on a straightforward method for preparing gelatin-based materials with iron oxide nanoparticles (G–Fe2O3 and G–Fe3O4) for external use. The newly obtained materials must be precisely tuned to match the requirements and usage situation because they will be in close touch with human/animal skin. The biocompatible structures formed by gelatin, tannic acid, and iron oxide nanoparticles were investigated by using FTIR spectroscopy, SEM-EDAX analysis, and contact angle methods. The physico-chemical properties were obtained by using mechanical investigations, dynamic vapor sorption analysis, and bulk magnetic determination. The size and shape of iron oxide nanoparticles dictates the magnetic behavior of the gelatin-based samples. The magnetization curves revealed a typical S-shaped superparamagnetic behavior which is evidence of improved MRI image accuracy. In addition, the MTT assay was used to demonstrate the non-toxicity of the samples, and the antibacterial test confirmed satisfactory findings for all G-based materials. [ABSTRACT FROM AUTHOR]

Simple Summary: Inorganic nanocrystals such as gold, iron oxide and semiconductor nanocrystals have intrinsic optical or magnetic properties that make them very promising for cancer detection, imaging and therapy. The surface ligands of these nanoparticles play a critical role in their application and control the nanoparticle interaction with biomolecules and cells. The complex nano-bio interface is, for this reason, gaining increasing attention, and many studies are devoted to either propose new surface chemistries or characterize their impact on nanoparticle imaging and/or therapeutic efficiency. This review presents a general perspective on the design of nanoparticle surface chemistry. Inorganic nanocrystals, such as gold, iron oxide and semiconductor quantum dots, offer promising prospects for cancer diagnostics, imaging and therapy, due to their specific plasmonic, magnetic or fluorescent properties. The organic coating, or surface ligands, of these nanoparticles ensures their colloidal stability in complex biological fluids and enables their functionalization with targeting functions. It also controls the interactions of the nanoparticle with biomolecules in their environment. It therefore plays a crucial role in determining nanoparticle biodistribution and, ultimately, the imaging or therapeutic efficiency. This review summarizes the various strategies used to develop optimal surface chemistries for the in vivo preclinical and clinical application of inorganic nanocrystals. It discusses the current understanding of the influence of the nanoparticle surface chemistry on its colloidal stability, interaction with proteins, biodistribution and tumor uptake, and the requirements to develop an optimal surface chemistry. [ABSTRACT FROM AUTHOR]

Iron‐based magnetic nanoparticles (MNPs) have been studied extensively for the past few decades. They have been applied in various applications, particularly in the biomedical sector. Due to their excellent physical and chemical properties, they have also been used widely in the agricultural sector. MNPs can be synthesized inexpensively and applied in large scale agricultural activities. This paper highlights the applications of iron‐based MNPs in the agricultural sector mainly as antimicrobial agents, plant growth promoters, site‐targeted delivery agents, nanosensors, detection and remediation for pesticide residue. Furthermore, the toxicity and transport of iron‐based MNPs in the soil‐plant system are also elucidated. These aspects have to be well‐understood before MNPs can be fully implemented effectively this pin the agricultural sector. Lastly, a hybrid nanomaterial, which is consisted of iron and magnesium oxide (MgO) nanoparticles (NPs), is proposed. This hybrid nanomaterial is expected to overcome the shortcomings of iron‐based MNPs. [ABSTRACT FROM AUTHOR]

Iron-oxide-doped polyaniline (PANI-IO) thin films were obtained by the polymerization of aniline monomers and iron oxide solutions in direct current glow discharge plasma in the absence of a buffer gas for the first time. The PANI-IO thin films were deposited on optical polished Si wafers in order to study surface morphology and evaluate their in vitro biocompatibility. The characterization of the coatings was accomplished using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), metallographic microscopy (MM), and X-ray photoelectron spectroscopy (XPS). In vitro biocompatibility assessments were also conducted on the PANI-IO thin films. It was observed that a uniform distribution of iron oxide particles inside the PANI layers was obtained. The constituent elements of the coatings were uniformly distributed. The Fe-O bonds were associated with magnetite in the XPS studies. The surface morphology of the PANI-IO thin films was assessed by atomic force microscopy (AFM). The AFM topographies revealed that PANI-IO exhibited the morphology of a uniformly distributed and continuous layer. The viability of Caco-2 cells cultured on the Si substrate and PANI-IO coating was not significantly modified compared to control cells. Moreover, after 24 h of incubation, we observed no increase in LDH activity in media in comparison to the control. In addition, our results revealed that the NO levels for the Si substrate and PANI-IO coating were similar to those found in the control sample. [ABSTRACT FROM AUTHOR]

The necessity for large scale and sustainable energy storage systems is increasing. Lithium-ion batteries have been extensively utilized over the past decades for a range of applications including electronic devices and electric vehicles due to their distinguishing characteristics. Nevertheless, their massive deployment can be questionable due to use of critical materials as well as limited lithium resources and growing costs of extraction. One of the emerging alternative candidates is potassium-ion battery technology due to potassium's extensive reserves along with its physical and chemical properties similar to lithium. The challenge to develop anode materials with good rate capability, stability and high safety yet remains. Iron oxides are potentially promising anodes for both battery systems due to their high theoretical capacity, low cost and abundant reserves, which aligns with the targets of large-scale application and limited environmental footprint. However, they present relevant limitations such as low electronic conductivity, significant volume changes and inadequate energy efficiency. In this review, we discuss some recent design strategies of iron oxide-based materials for both electrochemical systems and highlight the relationships of their structure performance in nanostructured anodes. Finally, we outline challenges and opportunities for these materials for possible development of KIBs as a complementary technology to LIBs. [ABSTRACT FROM AUTHOR]

Probability density functional method was used to determine whether interaction between mechanical force and chemical action in cleaning was an additive effect, a synergistic effect, or an offsetting effect. As a soiled sample, iron (III) oxide soiled fabric, Sudan IV soiled fabric, commercially available artificial soiled fabric containing mixed stains, etc. were used and washed with a tergotometer. Mean value μrl and standard deviation σrl of the cleaning force distribution were calculated by using probability density functional method, and the interaction was judged using Δμrl which is the difference between μrl obtained under the two conditions. As results, additive effects between the mechanical force and the pH effect were confirmed in the cleaning of iron (III) oxide soiled fabric and commercially available artificially soiled fabric, and an additive effect between the mechanical force and the effect of the surfactant concentration was confirmed in the cleaning of Sudan IV soiled fabric. Therefore, it was presumed that an additive effect is often established between the mechanical action and the chemical action in cleaning, rather than a synergistic effect or an offsetting effect. [ABSTRACT FROM AUTHOR]

The aim of this work was to study the influence of copper content and particle morphology on the performance of Cu/FeOx catalysts in the gas-phase conversion of CO2 with hydrogen. All four investigated catalysts with a copper content between 0 and 5 wt% were found highly efficient, with CO2 conversion reaching 36.8%, and their selectivity towards C1 versus C2-C4, C2-C4=, and C5+ products was dependent on catalyst composition, morphology, and temperature. The observed range of products is different from those observed for catalysts with similar composition but synthesized using other precursors and chemistries, which yield different morphologies. The findings presented in this paper indicate potential new ways of tuning the morphology and composition of iron-oxide-based particles, ultimately yielding catalyst compositions and morphologies with variable catalytic performances. [ABSTRACT FROM AUTHOR]

Our knowledge of electromagnetic heating's effect on heavy oil upgrading is largely based on very limited data. The aim of the present research was thus to study in detail the effect of microwave exposure in the absence and presence of nanosized magnetite on the composition of heavy oil. The obtained data reveal that the use of nanosized magnetite improves not only microwave radiation application as a result of its absorption and release of thermal energy but also that these nanoparticles have a catalytic ability to break carbon–heteroatom bonds in the composition of resins and asphaltene molecules. In fact, the overall reduction in asphaltenes or resins does not always adequately describe very important changes in asphaltene composition. Even a small fraction of broken carbon–heteroatom bonds can lead to an increase in the mobility of asphaltenes. Moreover, this study has shed light on the important evidence for asphaltenes' transformation, which was found to be the formation of light aromatic compounds, such as alkylbenzenes, naphthalenes and phenanthrenes. These compounds were fixed in the composition of the aromatic fraction. We believe that these compounds could be the fragments obtained from asphaltenes' degradation. The evidence from this study points toward the idea that asphaltenes' destruction is crucial for increasing oil mobility in the reservoir rock during its thermal stimulation. [ABSTRACT FROM AUTHOR]

The electrical conductivities of iron-bearing minerals are important for understanding the chemical and thermal heterogeneity of the Earth's mantle. Recent high-pressure experiments have shown that the new iron oxide group (FeO)m(Fe2O3)n is stable under mantle conditions. Although the new iron oxides possibly play an important role in the subduction zone, the physical properties of these iron oxides are still unclear. Here, we determined the electrical conductivities of Fe4O5, Fe5O6, and Fe7O9 at pressures up to 60 GPa using diamond anvil cells. The electrical conductivities of the iron oxides generally increased with increasing pressure, and the values were comparable with previous data for Fe3O4 and FeO at high pressures. Although iron oxides with a mixed-valence state are generally highly conductive, Fe7O9 was less conductive than Fe4O5 and Fe5O6. This difference is likely due to the ordered sites and valences in the structures of Fe4O5 and Fe5O6. The results show that the new iron oxides were not metallic under the experimental conditions. The iron oxides in the subducted materials may cause anomalies in the electrical conductivity of the deep mantle along with the melt and water. [ABSTRACT FROM AUTHOR]

The sustainability of clean water supply remains as one of the grand crises faced by today's world. The rapid expansion of membrane technology has opened up the opportunities for its applications in the sector of water and wastewater treatment. However, the commercial polymeric membranes are suffered from low degree of hydrophilicity and prone to different types of surface fouling. The incorporation of inorganic nanomaterials as nanofillers within polymeric matrix to produce nanocomposite membranes has received enormous attention because of its ability to resolve underlying issues encountered by conventional polymeric membranes. Among various nanoparticles, iron oxide (Fe3O4) nanoparticles have sparked great interest in the fabrication of nanocomposite membranes owing to its intrinsic properties that could improve not only the membrane surface hydrophilicity and antifouling properties but also its removal rates against pollutants via sieving and/or adsorption mechanisms. This review aims to provide insights on the recent advances of Fe3O4-modified microporous membranes for both water and wastewater treatment. Novel strategies such as surface functionalization and nanohybridization of Fe3O4 nanoparticles and its impacts on membrane physicochemical properties and separation performances have been explored and critically reviewed. Finally, the technical challenges in utilizing Fe3O4-modified microporous membranes for potential applications in real operation are also discussed. [ABSTRACT FROM AUTHOR]

This study focused on developing a superparamagnetic graphene oxide-based nanocomposite consisting of iron oxide (IO) and gold nanoparticles for quercetin delivery. For this purpose, the structure and morphology of the designed nanocomposite (GO/IO/Au) were investigated by several characterization methods such as fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, vibrating-sample magnetometer (VSM) analysis, field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM). Then, the biocompatibility of the synthesized nanocomposite was studied by Brine shrimp Artemia lethality assay, red blood cell hemolysis assay, and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. Moreover, the GO/IO/Au nanocomposite efficiency as an anticancer drug delivery system was evaluated in vitro conditions. The results showed that the designed nanocomposite is highly biocompatible and possesses a favorable magnetization (Ms = 29.2 emu.g−1) making it a good candidate for biomedical applications. Also, it was confirmed that GO/IO/Au nanocomposite is a potent drug carrier that can effectively deliver quercetin to cancer cells. [ABSTRACT FROM AUTHOR]

Undoped and Mg-doped (y = [Mg2+]/[Fe3+] = 1, 2, 3, and 4 at.%) Fe2O3 thin films were synthesized by a simple spray pyrolysis technique. The thin films were extensively characterized. X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) analysis confirmed the successful insertion of Mg in the rhombohedral structure of Fe2O3. In addition, scanning electronic microscope (SEM) and confocal microscope (CM) images showed a homogenous texture of the film, which was free of defects. The rough surface of the film obtained by spray pyrolysis is an important feature for photocatalysis and gas sensor applications. The direct band gap of the doped Fe2O3 films obtained for [Mg2+]/[Fe3+] = 3 at.% was Edir = 2.20 eV, which recommends the Mg-doped iron oxide as an optical window or buffer layer in solar cell devices. The photodegradation performance of Mg-doped Fe2O3 was assessed by studying the removal of methylene blue (MB) under sunlight irradiation, with an effective removal efficiency of 90% within 180 min. The excellent photodegradation activity was attributed to the strong absorption of Mg-doped Fe2O3 in the UV and most of the visible light, and to the effective separation of photogenerated charge carriers. [ABSTRACT FROM AUTHOR]

Nanostructured electrode materials for supercapacitors have attracted research interest due to their high power density and long cycle life. Herein, porous flower-like magnetite (Fe3O4) nanostructures have been synthesized using ethylene glycol mediated iron alkoxide as a precursor material. The magnetite nanostructures are prepared by heating an iron alkoxide at 450 °C for 3 h under N2 atmosphere. The prepared porous nanostructure is polycrystalline with a high surface area of 186 m2 g−1 and existence of pores with a pore volume 6.6 nm. The electrochemical capacitance performance of Fe3O4 nanostructures has been evaluated. The high discharge capacitance is 183 F g−1 at 1 A g-1 with high capacitance retention of about 65% upon charge–discharge cycling after 5000 cycles have been observed. The high discharge rate and cyclic stability are attributed to the porous nature of the Fe3O4 nanostructures. As Fe3O4 is inexpensive, relatively non-toxic, and environmental friendly nature has potential application for supercapacitors. [ABSTRACT FROM AUTHOR]

A porous hematite/alumina nanocomposite is produced by sol-gel combustion synthesis. The XRPD, Raman and FTIR methods show the presence of α-Fe 2 O 3 phase while SEM, TEM, EDS and BET techniques further reveal the formation of porous ellipsoid-like nanostructure of hematite nanoparticles coated by amorphous alumina. Hematite nanoparticles have a size of ~40 nm whereas the porous hematite/alumina nanocomposite particles are ~100 nm in size with characteristic pores of ~7 nm. The M(H) at 300 K exhibits coercivity H C = 293 Oe and magnetization M S = 2.71 emu/g and at 5 K H C = 1150 Oe and M S = 9.25 emu/g. The M(T) under H = 100 Oe shows a bifurcation between ZFC/FC magnetization curves at all measurement temperatures T irr >350 K (irreversibility temperature) and blocking temperature at TB ~ 305 K. Unexpectedly, the M(T) measurements under H = 10 kOe reveal the suppressed Morin transition at T M = 225 K. The analysis of the results and data from the literature reveal that the porous surface structure of hematite induces the atypical magnetic properties. A magnetic resonance imaging (MRI) properties show the transverse relaxivity rate (r2) of 0.44 mM−1s−1 at 7 T and 1.06 mM−1s−1 at 15.2 T. The investigated nanocomposite particles could be useful in biomedical applications due to their low cytotoxicity and porous nanostructure. [ABSTRACT FROM AUTHOR]

Summary: The performance of nanomaterials in energy storage devices and catalysts is influenced by their size and surface area. In addition, because the surface accessibility to ions or reactants significantly affects the performance of the devices, the surface area and pore structure of the nanomaterials are critical design parameters. Herein, a nanocomposite containing Fe3O4, SnO2, and reduced graphene oxide (rGO) is synthesized that exhibits superior pore structure and a significantly larger surface area (217.39 m2 g−1) compared to the single‐metal‐oxide composites, Fe3O4/rGO (68.88 m2 g−1) and SnO2/rGO (56.80 m2 g−1). Fe3O4/SnO2/rGO is used as a supercapacitor and a dye‐degrading photocatalyst, achieving a superior‐specific capacitance of 967.5 F g−1 at a current density of 1 A g−1 and long cycle stability (98% capacity retention over 5000 cycles at 10 A g−1). The photocatalytic activity of Fe3O4/SnO2/rGO was evaluated under visible light and showed significant degradation (92%) of methylene blue dye. The unexpectedly high surface area of Fe3O4/SnO2/rGO is credited to the synergistic interactions of Fe3O4, SnO2, and rGO, which prevent the growth and agglomeration of nanoparticles and thereby increase the surface area and electrical conductivity. These results provide meaningful insights to further improve the synthesis of active materials and catalysts with a large surface area via hydrothermal methods. Highlights: High surface area (217.39 m2/g) hydrothermally‐grown Fe3O4/SnO2/rGO Nanocomposite.Fe3O4/SnO2/rGO for energy and environmental remediation.Fe3O4/SnO2/rGO is nearly 3 folds superior to Fe3O4/rGO and SnO2/rGO.High‐capacitance of 967.5 F g−1 at a current density of 1 A g−1.Capacity retention of 98% over 5000 cycles.Easy‐recoverable photocatalyst for multiple uses with more than 90% photocatalytic activity. [ABSTRACT FROM AUTHOR]

A porous ball-flower-like Co3O4/Fe2O3 heterostructural photocatalyst was synthesized via a facile metal–organic-framework-templated method, and showed an excellent degradation performance in the model molecule rhodamine B under visible light irradiation. This enhanced photocatalytic activity can be attributed to abundant photo-generated holes and hydroxyl radicals, and the combined effects involving a porous structure, strong visible-light absorption, and improved interfacial charge separation. It is notable that the ecotoxicity of the treated reaction solution was also evaluated, confirming that an as-synthesized Co3O4/Fe2O3 catalyst could afford the sunlight-driven long-term recyclable degradation of dye-contaminated wastewater into non-toxic and colorless wastewater. [ABSTRACT FROM AUTHOR]

The "wet-rail" phenomenon results in low adhesion between wheel and rail throughout the year, occurring transiently on a slightly wet, or drying railhead. It has been previously proposed that it is caused by a mixture of iron oxides and small amounts of water (from dew or precipitation) on the railhead that form a friction reducing paste. This paper outlines a novel combination of rheology, modelling and experimental work using a twin disc test rig to determine how the rheology of this iron oxide paste affects adhesion. The yield strength of different types of iron oxides, along with solid oxide fraction of the friction reducing paste, was assessed and used as an input into an "adhesion model" for assessing water and oxide suspensions. The rheological and modelling results were compared against very low adhesion recorded in twin disc experimental validation when simulating the wet-rail phenomenon. [ABSTRACT FROM AUTHOR]

Background: Avian influenza virus (AIV) subtype H9N2 is a low pathogenic avian influenza virus (LPAIV). Objective: This study aims to evaluate the humoral and cellular immunity in vaccinated mice and broiler chicken by irradiated AIV antigen plus carboxymethyl chitosan bounded iron oxide nanoparticles (CMC‐IO NPs) as an adjuvant. Methods: AIV subtype H9N2 with 108.5 EID50/ml and haemagglutinin antigen assay about 10 log2 was irradiated by 30 kGy gamma radiation dose. Then, the gamma‐irradiated AIV was used as an inactivated vaccine and conjugated with CMC‐IO NPs to improve immune responses on mice. IO NPs must be applied in all activated tests using 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC) and N‐hydroxysulfosuccinimide sodium salt (sulfo‐NHS), and then functionalized by CMC as IO‐CMC. Fourier transform infrared (FTIR) spectra on functionalized IO‐CMC showed a peak of 638 cm−1 which is a band between metal and O (Fe‐O). Results: Based on the comparison between the two X‐ray diffraction (XRD) patterns on Fe2O3‐NPs and IO‐CMC, the characteristics of IO‐NPs did not change after carboxymethylation. A CHN Analyzer was applied to measure the molecular weight of IO‐CMC that was calculated as 1045 g. IO‐CMC, irradiated AIV‐IO‐CMC and formalin AIV‐IO‐CMC were injected into 42 BALB/c mice in six groups. The fourth group was the negative control, and the fifth and sixth groups were inoculated by irradiated AIV‐ISA70 and formalin AIV‐ISA70 vaccines. An increase in haemagglutination inhibition (HI) antibody titration was observed in the irradiated AIV‐IO‐CMC and formalin AIV‐IO‐CMC groups (p < 0.05). In addition, increases in the lymphoproliferative activity of re‐stimulated splenic lymphocytes, interfron‐γ (IFN‐γ) and interleukin‐2 (IL‐2) concentration in the irradiated AIV‐IO‐CMC group demonstrated the activation of Type 1 helper cells. The concentration of IL‐4 was without any significant increases in non‐group. Conclusions: Accordingly, Th2 activation represented no increase. Finally, the finding showed that AIV‐IO‐CMC was effective on enhancing immunogenicity as irradiated AIV antigen administered with a clinically acceptable adjuvant (i.e. IO‐CMC). [ABSTRACT FROM AUTHOR]

Both basalt fibers and glass fibers can be used as reinforced material in fiber-reinforced polymer (FRP) composites. In this paper, the tensile strength, elastic modulus, and hardness of basalt fibers and E-glass fibers are studied by fiber tensile tester and nanoindentation. The crystalline phase and structural feature of fibers are conducted by X-ray diffraction (XRD) and Fourier transform infra-red (FTIR) spectroscopy. The results show that the mechanical properties of basalt fibers are higher than those of E-glass fibers. The density of basalt glasses is higher than that of E-glass and increases with increasing iron content. XRD patterns show that both basalt fibers and E-glass fibers are totally amorphous. Fe3+ mainly exists in the form of [FeO6] in the glass network. It indicates that iron oxide plays a key role in improving the mechanical properties of basalt fibers. [ABSTRACT FROM AUTHOR]

The capability of laser ablation method in producing gold/iron oxide nanocomposite was studied experimentally. At first, Au and FeO nanoparticles (NPs) were synthesized in distilled water by laser ablation method. The fundamental wavelength of a Q-switched Nd:YAG laser with 6 ns pulse width was employed to synthesize nanoparticles. Then mixtures of suspensions in different volumetric ratio were prepared and irradiated by the second harmonic beam of Nd:YAG laser at 532 nm to transfer energy to the mixtures and produce nanocomposite. Volumetric ratio of nanoparticles suspension in the mixtures was 1/1, 1/2 and 2/1. Several analytical techniques such as UV–Vis-NIR spectroscopy, X-ray diffraction, DLS measurement, FTIR spectrum, photoluminescence (PL) spectroscopy and TEM and SEM imaging were applied to characterize the products. According to the SEM micrographs, after green laser irradiation, Au NPs were melted and deformed and FeO nanoparticles were resided and connected to their surface. Results show that post irradiation of mixtures of nanoparticles by green laser is capable to create nanocomposite. In comparison with chemical based methods to produce composite nanostructures, this method is easy, fast and environmentally friendly method. [ABSTRACT FROM AUTHOR]

Magnetic photocatalysts were obtained with different TiO2 (Ti) contents supported on the core–shell structure, SiO2@δ-FeOOH, obtaining the the main photocatalysts 30, 50 and 80 Ti/Si@Fe. The characterization performed by DSC and TGA showed that the feroxyhyte undergoes dehydroxylation between 120 and 190 °C and indicated the formation of Fe2O3. The results obtained by XRD confirmed the conversion from δ-FeOOH to γ-Fe2O3 and α-Fe2O3 during the heat treatment performed to support TiO2 P25 in the SiO2@δ-FeOOH composite. The formation of silica on δ-FeOOH was confirmed by ATR analysis and the core–shell structure by TEM images. The efficiency in the separation stage of the photocatalysts from the aqueous medium was evaluated by sedimentation kinetics in the presence of a magnetic field. The results showed that the prepared materials can be quickly and simply separated due to their magnetic property. The efficiency of the magnetic photocatalysts to decolorize methylene blue dye in the presence of UV radiation ranged from 73 to 96% in 120 min of reaction, while the efficiency of the reactions carried out in sunlight ranged from 91 to 97% in just 60 min. These results show that Ti/Si@Fe photocatalysts can be prepared in a simple way, showing high photocatalytic efficiency being easily recovered and reused in other reactions, which generates cost savings. [ABSTRACT FROM AUTHOR]

Use of oscillating heat pipes as a new component related to heat transfer has always been of interest for different technologies in recent years. A novel U-shaped structure is designed for the 3D-PHPs and this novel design creates a high performance device. In this experimental study, the thermal performance of a newly designed three-dimensional pulsating heat pipe with Fe3O4 nanofluid exposed to magnetic field under different heat inputs (0 W to 450 W). The results showed that the filling ratio of 50 % had better thermal performance. Our results indicated that the use of iron oxide nanofluid (Fe3O4) at 2 % mass concentration significantly improves the thermal performance of the pulsating heat pipe especially in 50 % filling ratio compared to pure water, which also showed that the improvement of heat transfer coefficient can be better by using corrugated evaporator under magnetic field. The results show that when the evaporator of 3D-PHP is exposed to a constant magnetic field, the thermal performance of the device improves significantly. The results showed that thermal resistance has been reduced 18 %, 20 %, and 25 %, respectively, for nanofluid with 50 % filling ratio and corrugated evaporator and under magnetic field compared to water. Compared to pure water operating fluid, application of nanofluid, magnetic field, and corrugated evaporator reduces the average heat resistance and increases the heat transfer coefficient. This investigation will promote the development of effective cooling for electronic devices. [ABSTRACT FROM AUTHOR]

Iron-based oxides are an important class of magnetic materials and have extremely important uses in the electronics industry. The preparation of iron oxide into nanomaterials with special properties has aroused great interest and widespread concern from researchers. This article aims to study the preparation and characterization of low-dimensional nano-materials of iron oxides. In this paper, iron oxide nanomaterials were prepared by microemulsion method, and compared with other conventional methods such as hydrothermal method, thermal decomposition method and coprecipitation method to prepare the purity of iron oxide nanomaterials, the total yield of the experiment, the stability of the finished products Comparative analysis of the four aspects of sex and the total cost of the experiment to summarize the experimental data. The research results show that the microemulsion method has a purity of up to 99% and a yield of 86% compared to the other three methods. In terms of stability, the finished product prepared by the microemulsion method has better stability within two months. There is no obvious change; however, the finished products prepared by the other three methods have different degrees of degradation after one month, which fully proves that the finished products prepared by the microemulsion method have better stability. Comparing its cost, it is found that there is no significant difference in experimental cost. Therefore, the preparation of iron oxide low-dimensional nanomaterials by microemulsion method provides an important theoretical basis for the preparation of iron oxide nanomaterials in the future. [ABSTRACT FROM AUTHOR]

Every year, the steelmaking industry produces millions of tons of slags resulting in pollution to the environment. Among the waste, secondary metals and scales rich in iron oxides are also thrown away. There is a need to treat the steel waste in a reasonably way to protect the environment and proposing new cheap technologies for producing advanced materials. In this study we report the morphological and structural characterization of waste scales generated during roll milling steel process at JSC "Arcelor Mittal Temirtau". The raw slag and annealed at 1000 °C were measured by X-ray diffraction (XRD), scanning electron microscopy adapted with energy dispersive X-ray (SEM- EDX), magnetometry and Mössbauer Spectroscopy (MS). Fe and O were detected by EDX as main chemical elements and Si, S, Ca, Mg, C and Al as minimal elemental composition. XDR for the raw sample revealed α-Fe2O3 (hematite) and Fe3O4 (magnetite) as principal and secondary phase, respectively; whereas monophasic α-Fe2O3 is detected for the scales annealed at 1000 °C. Magnetometry measurements show the Verwey transition for the raw sample and the Morin transition for the annealed at 1000 °C; those are fingerprints for the presence of magnetite and hematite, respectively. MS measurements for the raw sample consist of 6 small peaks of absorption and a broad two-lines absorption peak in the central part. The doublets are associated to the hyperfine parameters belonging to wustite. Magnetite is related to the hyperfine parameters for two sextets in octahedral Fe2.5+ and tetrahedral Fe3+sites and a small sextet that resembles the Mössbauer parameters of α-Fe2O3. Only a well crystallized and weakly ferromagnetic sextet confirm the presence of α-Fe2O3 phase for the sample annealed at 1000 °C due to thermal oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] The adhesion of dissimilatory iron reducing bacteria (DIRB) to iron oxides is an important process to initiate direct extracellular electron transfer. Iron oxides in natural environments are often coated by organic matter or silica (SiO 2) which alters their surface physicochemical properties. To investigate the influence of these surface coatings, we characterized the dynamic adhesion processes of Shewanella oneidensis MR-1 to bare hematite, humic acid-coated hematite (hematite-HA), and SiO 2 -coated hematite (hematite-SiO 2) using Quartz Crystal Microbalance with Dissipation (QCM-D). The molecular-level process and mechanism were investigated using in situ Attenuated Total Reflectance - Fourier Transform Infrared (ATR-FTIR) spectrometry. We found that MR-1 formed a rigid bacterial layer on bare hematite. Coating with HA or SiO 2 decreased the surface cell density during the initial adhesion stage, and compromised the stability of the subsequent bacterial attachment. The FTIR combined with two-dimensional correlation spectroscopy (2D-COS) analysis showed that C-moieties of polysaccharides dominated interactions in initial adhesion on HA and SiO 2 -coated hematite. In the longer term, the HA coating hindered the adsorption of amide, but promoted the binding of polysaccharide C-moieties to hematite. We concluded that, in general, both the HA and SiO 2 coatings reduced the attachment of MR-1 on hematite. These results advance our understanding of the roles of surface coatings on microbe-mineral interactions, which has significant implications for a series of biogeochemical processes in nature. [ABSTRACT FROM AUTHOR]

[Display omitted] Access to detailed information on cells loaded with nanoparticles with nanoscale precision is of a long-standing interest in many areas of nanomedicine. In this context, designing a single experiment able to provide statistical mean data from a large number of living unsectioned cells concerning information on the nanoparticle size and aggregation inside cell endosomes and accurate nanoparticle cell up-take is of paramount importance. Small-angle X-ray scattering (SAXS) is presented here as a tool to achieve such relevant data. Experiments were carried out in cultures of B16F0 murine melanoma and A549 human lung adenocarcinoma cell lines loaded with various iron oxide nanostructures displaying distinctive structural characteristics. Five systems of water-dispersible magnetic nanoparticles (MNP) of different size, polydispersity and morphology were analyzed, namely, nearly monodisperse MNP with 11 and 13 nm mean size coated with meso -2,3-dimercaptosuccinic acid, more polydisperse 6 nm colloids coated with citric acid and two nanoflowers (NF) systems of 24 and 27 nm in size resulting from the aggregation of 8 nm MNP. Up-take was determined for each system using B16F0 cells. Here we show that SAXS pattern provides high resolution information on nanoparticles disposition inside endosomes of the cytoplasm through the structure factor analysis, on nanoparticles size and dispersity after their incorporation by the cell and on up-take quantification from the extrapolation of the intensity in absolute scale to null scattering vector. We also report on the cell culture preparation to reach sensitivity for the observation of MNP inside cell endosomes using high brightness SAXS synchrotron source. Our results show that SAXS can become a valuable tool for analyzing MNP in cells and tissues. [ABSTRACT FROM AUTHOR]

Basalt fiber as a type of reinforced material has been widely used in fiber-reinforced polymer (FRP) composites. Iron oxide (Fe2O3) has a great influence on the thermal and elastic properties of basalt fiber. In this study, ultrabasic, basic, and intermediate basalt rocks were chosen as raw materials and the dependence of Fe2O3 content variations on the properties of basalt glass was explored. Results showed that the density, molar volume (Vm), and oxygen packing density (OPD) of basalt glasses increased with the increase of Fe2O3 content. The viscosity, as well as crystallization behavior, is dominated by Fe2O3 content. Besides, the addition of Fe2O3 contributed to increasing the elastic modulus and hardness of basalt glasses. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate at the mechanical characteristics of Fe3O4 particle reinforced with 7075 aluminium alloy composite. The composites of different weight percentage 2%, 4%, 6%, and 8% of Fe3O4 reinforcement were prepared using stir casting technique. Prepared composite samples were examined for mechanical properties like tensile percentage elongation and hardness test along with scanning electron microscopy. Additionally, corrosion was also conducted on the prepared samples. The results of mechanical properties reveal that improvement in hardness and tensile strength and corrosion resistance values with different weight percentage combinations. When compared to the original Al7075 alloy, the Ultimate Tensile Strength is highest at a value of 64.563% for 8% Fe3O4 reinforcement, and variation in Ultimate Tensile Strength is highest at a value of 21.865% for an increase in reinforcement percentage from 4% to 6% weight, according to the experimental studies.. [ABSTRACT FROM AUTHOR]

The translation of nanoparticles to useful applications is often hindered by the reliability of synthetic methodologies to reproducibly generate larger particles of uniform size (diameter > 20 nm). The inability to precisely control nanoparticle crystallinity, size, and shape has significant implications on observed properties and therefore applications. A series of iron oxide particles have been synthesised and the impact of size as they agglomerate in aqueous media undergoing flow through a capillary tube has been studied. Reaction conditions for the production of large (side length > 40 nm) cubic magnetite (Fe3O4) have been optimised to produce particles with different diameters up to 150 nm. We have focussed on reproducibility in synthesis rather than dispersity of the size distribution. A simple oxidative cleavage of the as-synthesised particles surfactant coating transforms the hydrophobic oleic acid coated Fe3O4 to a hydrophilic system based on azelaic acid. The hydrophilic coating can be further functionalised, in this case we have used a simple biocompatible polyethylene glycol (PEG) coating. The ability of particles to either chain, flow, and fully/or partially aggregate in aqueous media has been tested in a simple in-house system made from commercial components. Fe3O4 nanoparticles (60–85 nm) with a simple PEG coating were found to freely flow at a 2 mm distance from a magnet over 3 min at a rate of 1 mL min−1. Larger particles with side lengths of ~150 nm, or those without a PEG coating were not able to fully block the tube. Simple calculations have been performed to support these observations of magnetic agglomeration. Polyethylene glycol coated magnetite nanoparticles have been optimised for aqueous flow experiments. Particles agglomerate in the capillary tube while under the influence of a rare earth magnet. [ABSTRACT FROM AUTHOR]

The production of highly reactive oxygen carrier particles based on low-cost iron materials is explored for chemical looping processes. Ten different low-cost Fe-based materials in the micronized size, both minerals and industrial residues, have been tested as precursors of oxygen carrier particles. The redox reactivity of each of the materials is evaluated and compared to the state-of-the art with particulate materials, including one new material introduced in this work. Due to its excellent reactivity, Promifer material was used to produce oxygen carrier particles by pelletizing and granulation. Considering a trade-off between crushing strength and reactivity, pelletizing process was selected. This material calcined at 950 °C showed high reactivity with CH 4. If a higher operating temperature was required, e.g. 1000 °C with solid fuels, the reactivity decreased. Low attrition rates and good fluid-dynamic behavior with the pelletized particles, without agglomeration along the redox cycles, were found in a fluidized bed reactor. [Display omitted] • Identified iron oxides based on low-cost materials with high reactivity to methane. • Oxygen carrier particles prepared by clean methods with selected iron oxide precursor. • Characteristics of pelletized particles outperformed those of granulated particles. • Calcining temperature should be optimized considering reactivity and crushing strength. • Produced oxygen carrier improved characteristics of state-of-the-art Fe-based materials. [ABSTRACT FROM AUTHOR]

Cancer therapy triggered by various cell death pathways has attracted widespread attention to improve therapeutic efficiency. Herein, an immunomodulatory polysaccharide (galactoxyloglucan) coated iron oxide nanoconjugate, with a diameter of about 10 nm, is made-up to intracellularly trigger the Fenton reaction and achieve cell death. The nanoconjugate based on iron oxide nanoparticles (PIONPs) exhibits excellent biocompatibility, stability and can be used as an imaging agent. Moreover, importantly it can effectively generate reactive oxygen species (ROS) for tumor eradication with no systemic toxicity. In vitro and In vivo experiments reveal that the PIONPs can intratumorally accumulate and serves as an excellent MRI contrast agent. [ABSTRACT FROM AUTHOR]

A peerless inexpensive electrochemical engineering of spherical Pt nanoparticles (nano-Pt: ca. 100 nm in average diameter) was achieved with intersected ferric oxyhydroxide nanotubes (α-FeOOH (goethite): ca. 20 nm in average diameter). The FeOOH@Pt catalyst exhibited ca. 2.5 and 1.94-times increases in the catalytic activity and poisoning tolerance, respectively, of the formic acid electro−oxidation (FAO) – the anodic reaction in the direct formic acid fuel cells (DFAFCs). Surprisingly, with a post-activation of the FeOOH@Pt catalyst at 0.48 V vs. reversible hydrogen electrode (RHE) in 0.2 mol L−1 NaOH, a favorable Fe2+/Fe3+ transformation succeeded to eliminate the permanent CO poisoning of Pt that impaired the catalytic performance of DFAFCs. This was synchronized (relatively to nano-Pt) with a four-fold increase in the catalytic efficiency, ca. −174 mV shift in the onset potential, and eightfold enhancement in the catalyst's durability for FAO. The activated FeOOH@Pt catalyst also showed a mass activity of 296 mA mg−1 Pt (at 0.8 V), which was ca. nine times higher than that (34 mA mg−1 Pt) of the commercial Pt/C catalyst. The ascertained improvement in the electron transfer at the FeOOH@Pt surface foresees quick industrialization for DFAFCs. TOC. A simple layer-by-layer electrochemical assembly and a post-activation of a peerless inexpensive FeOOH/Pt/GC nanostructured catalyst was recommended for "mitigated CO-poisoning" formic acid electro−oxidation. [Display omitted] • An efficient and robust FeOOH/Pt anodic catalyst was developed for the direct formic acid fuel cells (DFAFCs). • The catalyst's activation at 0.48 V vs. RHE in NaOH resulted in a boosted (fourfold) catalytic performance. • The activation enriched the catalyst surface with α-FeOOH (goethite phase). • The electronic properties of Pt were tuned to accelerate the charge transfer of FAO. • The peerless inexpensive modification of Pt with FeOOH will sustain the market to realize DFAFCs. [ABSTRACT FROM AUTHOR]

The aim of this work is to show how the magnetic properties of polyethyleneimine (PEI)-coated and naked magnetite (Fe3O4) nanoparticles are improved when the alternative in situ PEI microwave-assisted hydrothermal synthesis method is employed in contrast to the results obtained for nanoparticles synthesized from the same precursors by a conventional co-precipitation method. As far as we know, this is the first report on "in situ" PEI-coated Fe3O4 nanoparticles obtained by microwave-assisted hydrothermal synthesis. For this purpose, uncoated and PEI-coated Fe3O4 nanoparticles were synthesized by the co-precipitation method (CCPM) using ammoniac as precipitating agent after heating at 80 °C and by a microwave-assisted hydrothermal method (MWAM) using urea at 140 °C during 30 min. The obtained powders so were characterized by X-ray diffraction, scanning and transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, Mössbauer spectroscopy and DC magnetization studies. It was seen that the magnetic properties of the nanoparticles strongly depend on the synthesis route and that they also vary if particles are coated by the nonmagnetic polymer (PEI). The morphology, size, surface and anisotropy effects play an important role in the magnetic behavior. In situ PEI-coated nanoparticles obtained by MWAM, with larger average size and better crystallinity, exhibited a higher coercive field and saturation magnetization values than PEI-coated nanoparticles synthesized by CCPM; the latter revealed a quasi-complete superparamagnetic behavior at room temperature. The synthesis by MWAM is a faster, simple and low-cost way to obtain in situ PEI-coated Fe3O4 nanoparticles with reasonable saturation magnetization, coercivity and suitable average particle size values to be tested for biomedical applications. [ABSTRACT FROM AUTHOR]

Owing to high stability, metal oxide-based ceramic thin films are of great interest for photocatalytic oxidation of water. Therefore, the current research is focused on the fabrication of different transition metal oxide thin films to estimate their photocatalytic efficiency. In the present research thin films of oxides of iron and yttrium are prepared on FTO glass substrate via Aerosol Assisted Chemical Vapor Deposition (AACVD) from methanol solution of iron and yttrium acetate precursors. The deposition of targeted films Fe2O3 and Y2O3 were carried out at 420 and 450 °C respectively under the argon gas flow of 120 cm3/min. Thin films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), to determine their phase and morphology. The direct energy band gaps were determined via Tauc's plot that gave values of 2.05 eV and 3.3 eV for oxides of iron and yttrium respectively. The photoelectrochemical water splitting response of the as-fabricated transition metal oxide as working electrodes were measured using linear scan voltammetry. The maximum value of photocurrent density recorded under the illumination with xenon lamp at 1.2 V vs. RHE was equal to 2.5 mA/cm2 and 0.3 mA/cm2 for Fe2O3 and Y2O3 thin films, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Influence Cu on WGS catalysts under ambient (2 bar) and industrial (25 bar) conditions. • Mössbauer spectroscopy used for phase identification. • Cu doping favors ferrihydrite at the expense of hematite in the precursor. • Cu forms a metallic phase at the surface after activation, enhances WGS activity. • Copper does not affect the Fe2+/Fe3+ ratio in magnetite unlike chromium. Copper promotion of chromium-doped iron oxide prepared via co-precipitation for high-temperature water–gas shift (WGS) catalysis is investigated. Low-temperature Mössbauer spectra demonstrate that copper doping delays hematite (α-Fe 2 O 3) formation in the fresh catalyst, favoring the formation of small crystallites of ferrihydrite (Fe 5 HO 8 ∙4 H 2 O). Catalysts are treated under industrial WGS conditions at 360 °C (activity evaluation) and 450 °C (ageing) at 2 and 25 bar. Mössbauer spectra show that chromium is incorporated in octahedral sites of the active magnetite (Fe 3 O 4) phase, resulting in a partially oxidized structure. Copper doping did not affect the bulk magnetite structure of the activated catalyst, which points to the presence of a separate copper phase. Near-ambient pressure XPS shows that copper is in the metallic state. XPS of discharged catalysts evidenced that reaction at elevated pressure resulted in the surface reduction of Fe3+ to Fe2+. Copper promotion enhances CO conversion under high-temperature WGS conditions. [ABSTRACT FROM AUTHOR]

Iron oxide (Fe2O3) nanoparticles are of great interest compared to their bulk counterpart due to their higher surface area, enhanced possibilities of bio-distribution and high rate of reactivity. In the present work, we report a simple, rapid, and cost-effective method for the synthesis of Fe2O3 nanoparticles based on the aqueous-gaseous phase reaction of iron (III) chloride solution by ammonia vapor. Post-physicochemical characterization of these nanoparticles, we have further reported that these positive surface charged containing particles can increase the plant growth under in vitro conditions. Investigations on maize plant show that Fe2O3 nanoparticles could have potential as a fertilizer substituent. Moreover, these particles were found to exhibit good photocatalytic activity against Rhodamine B, indicating their potential use toward soil remediation affected with industrial wastewater from dye industries. [ABSTRACT FROM AUTHOR]

Magnetic iron oxide nanoparticles (NPs) have been widely used as contrast agents in magnetic resonance imaging. In recent years, interest has been focused on obtaining and functionalizing them to make them better vectors and more soluble or specific to a given target. In the present work, we report the synthesis and characterization of NPs functionalized with two naphthalene derivatives (Amylovis®), which exhibit high affinity for ß-amyloid plaques characteristic of Alzheimer's disease (AD). These ones were characterized by FT-IR, TGA, DLS and SEM. The obtained NPs were conjugated by Steglich's method to two different Amylovis® molecules, determined this by ligand differences on the surface of the synthesized NPs. Amylovis® functionalized NPs could be useful for the detection of amyloid plaques that would contribute to an early diagnosis of AD. [ABSTRACT FROM AUTHOR]

[Display omitted] • Preparation of a biochar-iron oxide (BC-IO) composite via ultrasonication. • High specific surface area of BC-IO enables high heavy metal adsorption. • BC-IO outperformed unmodified BC in adsorption capacity. • BC-IO composite can be reused through adsorption and desorption. In this study, we aimed to develop an absorbent for efficient removal of heavy metals. We developed a composite (BC-IO x) using biochar (BC) obtained by carbonizing rice hull, a type of biomass, and iron(III) nitrate nonhydrate (IO). The bonding strength between BC and IO was increased through ultrasonication with high energy at 25 ℃ and a 2-h heat treatment process at 350 ℃. Brunauer-Emmett-Teller analysis showed that BC-IO x had an increased specific surface area, which was proportional to iron loading and provided an abundance of active heavy metal adsorption sites. This composite effectively removed Pb(II) and As(V). The addition of BC-IO 3 to Pb(II)-contaminated water for 120 min increased Pb(II) absorption capacity to 90.21 mg/g from 18.12 mg/g with unmodified BC. The As(V) adsorption capacity increased from 8.33 mg/g for unmodified BC to 65.34 mg/g for BC-IO 10. In addition, the potential adsorption mechanism was discussed using detailed chemical and physical analyses. The synthesis of a composite from biochar and iron oxide can inspire the cost-effective and straightforward production of heavy metal absorbents that can be utilized on a large scale. [ABSTRACT FROM AUTHOR]

Iron-based materials are extensively employed as oxygen carriers in chemical looping processes, but their long-term performance is often inhibited by sintering and agglomeration. Here, we developed a yolk–shell structured Fe 2 O 3 @Y 2 O 3 oxygen carrier, with each unit consisting of a Y 2 O 3 shell encapsulating a nano-sized Fe 2 O 3 core. The Y 2 O 3 shell could protect the redox-active cores from sintering, and the void between the yolk and the shell is capable of tolerating cyclic volume and phase changes. During the simulated chemical looping cycles at 600 °C, the Fe 2 O 3 @Y 2 O 3 oxygen carriers exhibit a consistent oxygen carrying capacity of 3 wt% over 50 cycles, without any distinguishable structural deterioration. With rational structure optimization, the Fe 2 O 3 @Y 2 O 3 oxygen carriers with porous shell could enhance the mass transfer across the shell and enable higher reaction rates. The satisfactory sintering resistance of the Fe 2 O 3 @Y 2 O 3 nanostructure demonstrates the feasibility of employing well defined yolk–shell structured oxygen carriers for chemical looping applications. [Display omitted] • Facile synthesis of well-defined Fe 2 O 3 @Y 2 O 3 yolk–shell nanostructured oxygen carriers. • A consistent oxygen carrying capacity of ∼3 wt% over 50 consecutive redox cycles. • The Yttria shell could protect the redox-active cores from sintering and agglomeration. • Enhanced mass transfer was achieved by modifying the shell porosity. [ABSTRACT FROM AUTHOR]

[Display omitted] • α-Fe 2 O 3 was evaluated as anode of solid-state batteries using oxide electrolyte. • Smaller Fe 2 O 3 particles showed better anode performance. • Contact area between Fe 2 O 3 and the electrolyte was increased to improve performance. • Fe 2 O 3 anode operated for the first time in oxide-based solid-state Li batteries. As Li-ion battery anode materials, two types of hematite (Fe 2 O 3 (big), Fe 2 O 3 (ultrafine)) were evaluated by using liquid electrolyte and oxide-based solid electrolyte. Although the anode using Fe 2 O 3 (ultrafine) with larger specific surface area showed a high initial reversible capacity in the liquid-electrolyte cell, there was a steep capacity decay in the cycling test. In the solid-electrolyte cell, we obtained very low reversible capacities of 40 mA h g−1 for the anode using Fe 2 O 3 (big) with smaller specific surface area. In contrast, the capacity of Fe 2 O 3 (ultrafine) anode was as high as 400 mA h g−1 at the 20th cycle. This is the first demonstration of charge–discharge reactions for Fe 2 O 3 anode in oxide-based solid-state batteries. The Fe 2 O 3 (ultrafine) particles were dispersed relatively uniformly between solid electrolyte in the active layer, suggesting that the contact area between Fe 2 O 3 and solid electrolyte becomes large. Consequently, Fe 2 O 3 (ultrafine) could benefit from larger contact area delivering the suitable reaction site for Li+ to improve the anode performance. [ABSTRACT FROM AUTHOR]

Hematite nanoparticles commonly undergoes isomorphic substitution of Al3+ in nature, while how the Al-substitution-induced morphological change, defective structure and newly generated Al–OH sites affect the adsorption behavior of hematite for contaminants remains poorly understood. Herein, the interfacial reactions between Al-substituted hematite and Pb2+ was investigated via CD-MUSIC modeling and DFT calculations. As the Al content increased from 0% to 9.4%, Al-substitution promoted the proportion of (001) facets and caused Fe vacancies on hematite, which increased the total active site density of hematite from 5.60 to 17.60 sites/nm2. The surface positive charge of hematite significantly increased from 0.096 to 0.418 C/m2 at pH 5.0 due to the increases in site density and proton affinity (log K H) of hematite under Al-substitution. The adsorption amount of hematite for Pb2+ increased from 3.92 to 9.74 mmol/kg at pH 5.0 and 20 μmol/L initial Pb2+ concentration with increasing Al content. More Fe vacancies may lead to a weaker adsorption energy (E ad) of hematite for Pb2+, while the E ad was enhanced at higher Al content. The adsorption affinity (log K Pb) of bidentate Pb complexes slightly increased while that of tridentate Pb complexes decreased with increasing Al content due to the presence of ≡ AlOH−0.5 and ≡ Fe 2 AlO−0.5 sites. Tridentate Pb complexes were dominant species on the surface of pure hematite, while bidentate ones became more dominant with increasing Al content. The obtained model parameters and molecular scale information are of great importance for better describing and predicting the environmental fate of toxic heavy metals in terrestrial and aquatic environments. [Display omitted] • Adsorption of Al-hematite for Pb2+ was studied via CD-MUSIC and DFT calculation. • Al-substitution increased total active site density of hematite from 5.60 to 17.60 sites/nm2. • Al-substitution in hematite enhance its surface charge and Pb2+ adsorption. • Presence of ≡ AlOH−0.5 and ≡ Fe 2 AlO−0.5 sites altered the log K Pb and E ads of Pb2+ on hematite. • Bidentate Pb complexes became more dominant on hematite with increasing Al content. [ABSTRACT FROM AUTHOR]

Pesticides can have harmful impacts on the environment and living organisms. Thus, removing them from polluted water is crucial. In this study, a bionanocomposite of carboxymethyl tragacanth- grafted -poly(3-aminophenol)/zinc oxide@iron oxide (CMT- g -P3AP/ZnO@Fe 3 O 4) synthesized by in situ copolymerization as an efficient adsorbent to eliminate the acetamiprid pesticide from polluted water. The CMT- g -P3AP/ZnO@Fe 3 O 4 magnetic nanocomposite was analyzed utilizing various techniques including FTIR, EDX, FESEM, XRD, BET, CHNSO, and TGA. The results displayed that the resulting nanocomposite with maximum adsorption capacity (Q max) successfully removed the acetamiprid pesticide from polluted water under optimal conditions such as pH of 7.00, 5.00 mg of adsorbent, 20.0 min duration, and 400 mg/L acetamiprid concentration. According to the linear Langmuir isotherm, the Q max of the biosorbent was 833 mg/g. The experimental adsorption data fitted well with Temkin's nonlinear isotherm model. The adsorption kinetic data were closely related to the Weber-Morris intraparticle diffusion nonlinear model. After three repetitive cycles, CMT- g -P3AP/ZnO@Fe 3 O 4 can be outstandingly renewed and recycled without significant reduction in its adsorption efficacy, as evidenced by the adsorption-desorption experiments. In addition, the CMT-g-P3AP/ZnO@Fe 3 O 4 displayed the good antibacterial activity against E. coli and S. aureus. [Display omitted] • Antibacterial magnetic bionanocomposite based on carboxymethyl tragacanth synthesized. • Antibacterial magnetic bionanocomposite used as a sorbent for acetamiprid removal. • Maximum adsorption capacity of the bionanocomposite for acetamiprid was 833 mg/g. • Bionanocomposite showed good antibacterial activity against E. coli and S. aureus. [ABSTRACT FROM AUTHOR]