Search

The electrocatalytic recycling of waste nitrate (NO3RR) is a promising decentralized route for green ammonia synthesis. Nonetheless, it suffers from the competing hydrogen evolution reaction and the insufficient proton supply in high pH conditions. Herein, iron oxide nanoparticles anchored on ZnO is introduced as a strategy to enhance the water dissociation ability and proton transfer rate, advancing NH4+ production from alkaline NO3RR. Supported by a set of ex situ and in situ characterization, the findings reveal the reduction of iron oxides, along with improvements in charge transfer properties and proton generation from H2O. Theoretical calculations show that iron oxides reduce the kinetic barrier of the rate‐limiting step (*NO2‐to‐*NO2H) and result in a thermodynamically favorable process to hydrogenation steps, which in turn reduce the overall energy barrier of alkaline NO3RR. Optimal catalytic activity is realized with a Fe loading of 0.5 wt.%, delivering a Faradaic efficiency of ≈83% for ammonium with a NH4+ yield rate of 31 nmol s−1 cm−2 at −0.7 V versus RHE. The results pave the way for the utilization of bi‐metal interaction to tune the reaction pathway for achieving sustainable ammonium synthesis in alkaline, contributing to ongoing efforts to achieve a sustainable nitrogen cycle via N‐based electrochemistry. [ABSTRACT FROM AUTHOR]

The application of iron oxide quantum dots (IOQDs) in this study led to the development of a straightforward, easy, and selective approach for cytosine sensing. To examine the capability of IOQDs in detecting nucleobases, attempts have been made to gain insight into the characteristics of IOQDs, including UV/Vis spectroscopic analysis, infrared spectroscopy, fluorescence spectroscopy, transmission electron microscopy, and powder‐XRD. We introduced IOQDs with a mean particle size distribution of 5.71 ± 0.08 nm for detecting cytosine by harnessing a turn‐on fluorescence phenomenon. The fostering fluorescence response of IOQDs was triggered in the presence of cytosine. In comparison, the presence of other nucleobases did not further induce the fluorescence signal of IOQDs. It was concluded that the hydrogen bonding bridging the carboxylate and hydroxyl groups on the surface of QDs with the amine groups of cytosine results in the elevation of IOQDs fluorescence. [ABSTRACT FROM AUTHOR]

Structured adsorbents have gained significant importance in gas separation applications due to their ability to fine‐tune mass and heat transfer and lower pressure drop across the bed. This study presents a ferromagnetic compressible hybrid structured adsorbent, allowing regeneration via magnetic induction heating. A compressible melamine sponge is coated with the CO2‐selective Ni‐MOF‐74 adsorbent and Fe3O4 as a ferromagnetic susceptor, capable of dissipating heat instantaneously in an alternating electromagnetic field. Taking advantage of these properties, the potential of rapid CO2 capture and thermal regeneration via magnetic induction swing adsorption is investigated. The successful incorporation of both ingredients on the melamine sponge is confirmed via SEM‐EDX and XRD analysis. Breakthrough experiments with a CO2/CH4‐mixture are performed. The selective property of Ni‐MOF‐74 toward CO2 is retained, with the composite showing a capacity of 1.89 mmol CO2/g. The compressible nature of the melamine sponge allowed for an improvement of 79% in the volumetric capacity of the adsorbent bed and a higher heating rate. In regard to regeneration, within 1 min of subjecting the structured composite to the alternating magnetic field, an efficient desorption (>90%) of CO2 is achieved. Overall, a ferromagnetic compressible hybrid structured adsorbent is presented for fast cyclic gas‐phase separation processes. [ABSTRACT FROM AUTHOR]

The effect of different substrate materials in the fabrication of an electrode intended for use in the water oxidation reaction is investigated. The electrocatalyst is nickel‐iron oxide (NiFeOx) which is deposited by chronoamperometry on nickel, iron, titanium, and stainless steel substrates. The process of electrodeposition is optimized to achieve the lowest overpotential for the water oxidation reaction. The four electrodes are characterized by scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), and glow‐discharge optical emission spectroscopy (GDOES) to describe the effect of the substrate on the nature of the electrocatalyst layer. Electrochemical tests in 1 m NaOH are applied on the four electrodes to assess the stability and the retention of the electrocatalytic properties of the whole electrode. All electrodes show similar overpotential of ≈0.3 V at 10 mA cm−2 implying that the substrate do not affect the electrocatalytic activity of the NiFeOx. After use, the overpotential increases in a range of 30–50 mV for nickel, iron, and titanium substrates, while stainless steel retains the lowest overpotential with an increase of 10 mV. This limited variation can be the effect of smaller NiFeOx nanoparticles compared to other substrates. XPS analysis reveals that after galvanostatic electrolysis, the oxidation state of Fe shifts slightly from Fe(II) to Fe(III), likely Fe3O4 and Fe2O3, while NiO/Ni2O3 change partially to Ni(OH)2. [ABSTRACT FROM AUTHOR]

Once dispersion and cytotoxicity issues are resolved, it has been proven that carbon nanotubes (CNTs) have great advantages in biomedical applications due to their unique properties. In this study, the superiority of carbon nanotubes was combined with magnetic targeting strategies, and a solution to the distribution problem in the aqueous media of the resulting CNTs decorated with iron oxide (mCNTs) was sought. A non‐covalent functionalization approach has been utilized to overcome this fundamental drawback of mCNTs. Conjugates of polyethylene glycol monomethyl ether and 9‐ fluorenyl methyl chloroformate (Fmoc) amino acids were used to coat the lateral surfaces of mCNTs, making them more water‐soluble. The selected Fmoc amino acids have different numbers of aromatic rings, which is known to affect the coating efficiency in non‐covalent functionalization and therefore, the dispersion behavior of the CNTs. Their coating yields, dispersion behaviors, magnetism, charge, and size properties have been determined. All coated mCNT samples displayed superparamagnetic behavior. Dispersion tests showed a promise to increase the stability of mCNTs with this approach. Moreover, we demonstrated that the functionalization of mCNTs affects cell viability in a dose‐dependent manner. The main finding of this study is that mCNTs can be successfully functionalized with Fmoc amino acid‐modified polyethylene glycol. [ABSTRACT FROM AUTHOR]

Thermal decomposition of iron oleate is a simple and widespread method for synthesizing monodispersed iron oxide nanoparticles (IONPs) with well‐defined morphology. However, the complexity of the underlying mechanism makes this method rather sensitive to variations in experimental conditions, and the lack of simple techniques to monitor the reaction progress in situ usually results in poor reproducibility and time‐consuming optimizations. Here, a simple, robust, and versatile in situ marker to monitor particle formation based on a sudden change in the temperature during reflux is reported. A linear relationship between the onset of particle formation and the concentration of surfactants is unveiled, corroborating a ‘chemically activated’ burst nucleation mechanism. Using this linear relationship as a guide, highly uniform spherical, cubic, and star‐shaped particles between 12 and 30 nm can be obtained. This temperature marker and the derived linear relationship not only deepen the understanding of the reaction process, but also provide a powerful tool for the straightforward optimization of IONPs. [ABSTRACT FROM AUTHOR]

The work reported here deals with fabricating iron oxide nanoparticles incorporated polyvinyl alcohol nanocomposite films via the solution‐casting green route, characterized using various characterization techniques. X‐ray diffraction analysis shows interaction of nanoparticles with the polyvinyl alcohol matrix, scanning electron microscopy shows surface morphology of crack‐free films, energy dispersive spectroscopy indicates elemental purity, tensiometer analysis shows changing behavior of hydrophilic to hydrophobic, thermogravimetric analysis shows improved thermal stability, ultraviolet‐visible spectroscopy shows tunable optical properties, and frequency response analysis shows improved electrical properties. A small incorporation (1 wt. %) of iron oxide nanoparticles has induced significant alternations in structural, wetting, thermal, optical, and electrical properties of the polyvinyl alcohol‐based nanocomposite films. Results showed notable changes in the structural phases, water contact angle (39.5° to 97.7°), optical absorption edge (5.12 eV to 4.84 eV), indirect band gap (4.99 eV to 4.68 eV), direct bandgap (5.41 eV to 5.21 eV), and band tail (0.57 eV to 0.89 eV) from native polyvinyl alcohol to polyvinyl alcohol/iron oxide nanocomposite films. Enhancements were observed in refractive indices, optical conductivity, optical dielectric loss, thermal stability, dielectric constant, and dielectric loss on incorporating iron oxide nanoparticles into the polyvinyl alcohol matrix. The fabricated nanocomposite films might be a potential material for optoelectronic and microelectronics applications. [ABSTRACT FROM AUTHOR]

Standard materials are often used to obtain spectra that can be compared to those from unknown samples. Spectra measured from these known substances are also used as a means of computing sensitivity factors to allow quantification by X‐ray photoelectron spectroscopy (XPS) of less well‐defined materials. Spectra from known materials also provide line shapes suitable for inclusion in spectral models which, when fitted to spectra, permit the chemical state for a sample to be assessed. Both types of information depend on isolating photoemission signals from the inelastically scattered signal. In this Insight note, technical issues associated with the use of XPS of as received Fe3O4 powder sample surface are discussed. The Insight note is designed to show how linear algebraic techniques applied to data collected from a sample marketed as pure Fe3O4 powder are used to verify that XPS has been performed on chemistry representative of the sample. The methods described in this Insight note can further be utilized in elucidating complex XPS data obtained from thin films formed or evolved during cyclic/non‐steady use of complex (electro)catalyst surfaces, especially in the presence of contaminants. [ABSTRACT FROM AUTHOR]

Magnetic iron oxide nanoparticles immobilized on microcrystalline cellulose (MCC) are studied for the adsorption of Pb(II) ions from an aqueous solution. Composites of iron oxide and MCC were synthesized with a 5%–20% loading of iron (w/w%). The effect of pH, concentration, and contact time was studied. The adsorption isotherms were fitted to nonlinear Langmuir, Freundlich, and Dubinin–Radushkevich (D‐R) isotherms, and kinetics were studied for pseudo‐first and second‐order kinetic fit models. Adsorption of Pb(II) ions increased with increasing pH value up to 5. Maximum adsorption of Pb(II) was observed up to 299.91 mg−1 in D‐R equilibrium for onto MCC‐Iron oxide composite for composite with iron loading of 20% at pH 5. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM) and spectral induced polarization (SIP) are widely used to investigate the electrical properties of mineral surfaces at vastly different scales of measurement. We compare AFM and SIP measurements made on two different materials (glass beads and silica gel) subjected to etching, deposition of iron oxide particles, and inclusion of calcite grains. We found that the treatments produced qualitatively consistent behaviors in the AFM and SIP data. Direct AFM measurements of surface charge density for silica and calcite surfaces were quantitatively compared to values estimated from the SIP results using a grain polarization model. No statistically significant difference (at a 95% confidence level) was found between the surface charge density of silica estimated by AFM (2.3 ± 6.6 mC/m2 for glass beads and 1.6 ± 0.1 mC/m2 for silica gel) versus SIP (5.4 ± 4.4 mC/m2 for glass beads and 1.6 ± 0.5 mC/m2 for silica gel). The surface charge density for calcite determined by AFM (43.5 ± 12.9 mC/m2) was approximately 19 times higher than that found for silica. While the charge density of calcite surfaces determined by SIP was also generally higher than that found for silica, different treatments produced significantly different values between 4.7 and 258 mC/m2 (with a maximum 95% CI of ±8.7 mC/m2). Several possible explanations exist for the range of the observed SIP measurements, including aging of the calcite surfaces. Overall, this study suggests the potential for the complementary use of AFM and SIP measurements to constrain future investigations of polarization mechanisms in porous media. Plain Language Summary: The electrical properties of rock and mineral surfaces are sensitive to their physical and chemical environment and are therefore important for earth applications ranging from detecting minerals to monitoring microbial growth. In most environmental settings, these properties are controlled by ions that move through the open pore spaces between grains and along mineral surfaces, where they are more tightly bound to charged surfaces. Atomic force microscopy (AFM) provides a way to directly measure the charge present on a mineral surface, but makes measurements at a microscopic scale and is not practical for field investigations or monitoring real‐time experiments in porous media. In contrast, spectral induced polarization (SIP) can measure electrical properties averaged over volumes of earth in the lab or field, but it is not always clear what exactly is being measured by this geophysical measurement. We therefore compare AFM and SIP measurements for glass beads and silica gel subjected to different treatments (etching, iron oxide deposition, and calcite formation) to assess whether these two distinct measurements provide consistent responses to the modifications. We found that the two measurements qualitatively provide consistent measurement responses and quantitatively determine similar amounts of charge present on mineral surfaces for both silica and calcite. The study suggests the combined use of AFM and SIP could improve our understanding of electrical process in porous media across measurement scales. Key Points: Atomic force microscopy (AFM) and spectral induced polarization (SIP) provide consistent information on the electrical properties of mineral surfaces despite having vastly different scales of measurementA grain polarization model was used to obtain consistent estimates of the surface charge density from SIP and AFM measurements for silica and calciteThe surface charge of calcite is an important contributor to the electrical response of porous media [ABSTRACT FROM AUTHOR]

Herein we synthesized biochar/iron oxide composite (C/α‐Fe2O3/γ‐Fe2O3) by two‐step calcination method. The prepared C/α‐Fe2O3/γ‐Fe2O3 had a highly pure and a concentration ratio of α‐Fe2O3 and γ‐Fe2O3 about 1 : 1. The optical properties of as‐synthesized C/α‐Fe2O3/γ‐Fe2O3 show a lower bandgap energy (1.90 eV) than that of pure C/α‐Fe2O3 (2.02 eV). The effects of different biochar composite catalysts on the removal of amino black were investigated. Upon illumination, the total removal rate of amino black dye by C/α‐Fe2O3/γ‐Fe2O3 catalyst reached 98 %, which was about 1.7 times that of C/α‐Fe2O3. In addition, the coercivity and the remanence intensity of C/α‐Fe2O3/γ‐Fe2O3 is respectively 1.81 times and 7.17 times that of C/α‐Fe2O3. The catalyst could be magnetically separated and reused for five times with a slight loss of its reactivity. The study of biochar composite provides a new direction for the removal of toxic organic dye in wastewater. [ABSTRACT FROM AUTHOR]

Fluorine magnetic resonance imaging (19F MRI) has emerged as an attractive alternative to conventional 1H MRI due to enhanced specificity deriving from negligible background signal in this modality. We report a dual nanoparticle conjugate (DNC) platform as an aptamer‐based sensor for use in 19F MRI. DNC consists of core–shell nanoparticles with a liquid perfluorocarbon core and a mesoporous silica shell (19F‐MSNs), which give a robust 19F MR signal, and superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic quenchers. Due to the strong magnetic quenching effects of SPIONs, this platform is uniquely sensitive and functions with a low concentration of SPIONs (4 equivalents) relative to 19F‐MSNs. The probe functions as a "turn‐on" sensor using target‐induced dissociation of DNA aptamers. The thrombin binding aptamer was incorporated as a proof‐of‐concept (DNCThr), and we demonstrate a significant increase in 19F MR signal intensity when DNCThr is incubated with human α‐thrombin. This proof‐of‐concept probe is highly versatile and can be adapted to sense ATP and kanamycin as well. Importantly, DNCThr generates a robust 19F MRI "hot‐spot" signal in response to thrombin in live mice, establishing this platform as a practical, versatile, and biologically relevant molecular imaging probe. [ABSTRACT FROM AUTHOR]

Significant quantities of Fenton sludge (FS) are produced during the treatment of industrial wastewater from the plating industry because of the removal of residual organic matter and color‐causing substances. This study proposes repurposing waste FS as a valuable resource to contribute to environmentally favorable remediation initiatives. This study focuses on producing Fenton sludge biochar (FS‐BC), which effectively removes As(V) from wastewater and offers a sustainable solution for wastewater treatment. Different FS‐BC samples were produced at various pyrolysis temperatures (300–900 °C), with FS‐BC‐900 exhibiting the greatest As(V) adsorption capacity. As(V) removal was primarily mediated by electrostatic attraction with iron oxide, and adsorption via inner‐sphere complex formation, as revealed by the XPS analysis. FS‐BC‐900 had a remarkable maximum As(V) adsorption capacity of 148.7 mg/g (initial concentration: 100–900 mg/l; reaction time: 96 h; pH 7.86), surpassing many other adsorbents reported in the literature. FS‐BC‐900 also demonstrated a high As(V) removal percentage, with 6.67 g/l of FS‐BC‐900 removing 96.8% of the As(V). Notably, the adsorption of As(V) by FS‐BC‐900 was affected by certain factors, including pH and carbonate presence. High pH and carbonate inhibited the ability of FS‐BC‐900 to adsorb As(V). This study presents a novel method for utilizing FS to combat As(V)‐contaminated water‐induced environmental contamination. This study contributes to eco‐friendly and sustainable wastewater treatment and As(V) remediation strategies by transforming waste into valuable resources. [ABSTRACT FROM AUTHOR]

The shape memory polymers (SMPs) is a potential alternative material for conventional shape memory alloys (SMAs) in various fields. Previous studies have focused on the application of SMPs materials as an alternative to SMAs. However, considering problems such as the poor mechanical properties, its application has been limited. This study developed a biodegradable, magnetically responsive SMPs material that can be used for medical implants with shape memory behavior under magnetic force and improved mechanical properties by adding nanoparticles. Moreover, effect of the added nanoparticle was investigated due to contents ratio. Nanocomposite was synthesized with polycaprolactone which has shape memory properties, Fe3O4 that generates heat under magnetic field, and carbon nanotubes with reinforcing effect. The morphology analysis confirmed the homogeneous dispersion of the Fe3O4/Carbon‐nanotubes (CNTs) in polymer matrix. The tensile test shows that tensile strength (14.9–17.6 MPa) increased when Fe3O4 (0–20 wt%) was included and that it did not increase significantly when CNTs (0–0.8 wt%) were included. The shape memory test result confirmed that developed composite had a shape memory under a magnetic field. It was confirmed that even if Fe3O4 was incorporated into polycaprolactone, did not lose its exothermic properties under magnetic field. The developed polymer showed high shape memory ratio (91%–98%) in all the nanoparticle content rates. With regard to biodegradability, weight loss occurred over time in the phosphate‐buffered saline solution. Therefore, the biocompatible, biodegradable, magnetic response shape memory polymer developed in this study might applied to various medical implant as advanced shape memory materials. [ABSTRACT FROM AUTHOR]

Wastewater pollution with organic compounds poses a serious threat to human health. One of the possible methods for solving these problems can be the use of micro/nanomotors. Among them, manganese‐based micro/nanomotors have a number of important advantages related to high catalytic activity, powerful motion, and low cost. Due to their mobility, micro/nanomotors promote an increase in the intensity of mass transfer in the reacting system. When introducing ferromagnetic elements into manganese‐based micro/nanomotors, it is possible not only to increase their motion speed, but also to make their motion more controllable. Herein, for the first time it demonstrates a synthesis method for MnFe2O4@Fe3O4/graphite and Mn2O3@Fe2O3@Fe3O4/graphite magnetic catalytic micromotors, which have remarkable photocatalytic properties. Micromotors are clusters of nanoparticles whose motion in a hydrogen peroxide solution in a non‐uniform magnetic field is caused by the action of magnetic force and self‐diffusiophoresis. Nanoparticles are synthesized by the plasma‐arc method with subsequent annealing in the air. When changing the annealing temperature, the catalytic and magnetic properties of nanoparticles can vary within a wide range of values. Micromotors MnFe2O4@Fe3O4/graphite have the most optimal catalytic and magnetic properties. The results of the research show that these micromotors are effective catalysts in the decomposition of methylene blue. [ABSTRACT FROM AUTHOR]

Hematite is a common iron oxide found in nature, and the α‐Fe2O3(0001) plane is prevalent on the nanomaterial utilized in photo‐ and electrocatalytic applications. The atomic‐scale structure of the surface remains controversial despite decades of study, partly because it depends on sample history as well as the preparation conditions. Here, a comprehensive study is performed using an arsenal of surface techniques (non‐contact atomic force microscopy, scanning tunneling microscopy, low‐energy electron diffraction, and X‐ray photoemission spectroscopy) complemented by analyses of the near surface region by high‐resolution transmission electron microscopy and electron energy loss spectroscopy. The results show that the so‐called "bi‐phase" termination forms even under highly oxidizing conditions; a (1 × 1) surface is only observed in the presence of impurities. Furthermore, it is shown that the biphase is actually a continuous layer distorted due to a mismatch with the subsurface layers, and thus not the proposed mixture of FeO(111) and α‐Fe2O3(0001) phases. Overall, the results show how combining surface and cross‐sectional imaging provides a full view that can be essential for understanding the role of the near‐surface region on oxide surface properties. [ABSTRACT FROM AUTHOR]

Chemical looping applications offer a variety of options to decarbonise different industrial sectors, such as iron and steel and hydrogen production. Chemical looping with water splitting (CLWS) is a chemical looping technology, which produces H2 while simultaneously capturing CO2. The selection of oxygen carriers (OCs) available to be used in CLWS is finite, due to the thermodynamic limitations of the oxidation with steam for different materials at the relevant process temperatures. Iron‐based materials are one of the most widely studied options for chemical looping combustion (CLC), touted for their relative abundance and low cost; likewise, for CLWS, iron is the most promising option. However, when the reduction of iron oxide (Fe2O3) is extended to wüstite (FeO) and iron (Fe), agglomeration and sintering problems are the main challenge for fluidisation. This work presents iron and tungsten mixed oxides as the OCs for a family of chemical looping applications. The OCs were produced via co‐precipitation; performance assessment was conducted in a thermogravimetric analyser and a lab‐scale fluidised bed reactor over continuous redox cycles. The use of tungsten combined with iron results in a solid solution of tungsten within the Fe2O3 matrix that produced a more mechanically stable material during operation, which performed well during multiple redox cycles with no apparent decrease in the oxygen transport capacity and showed no apparent agglomeration. Furthermore, materials containing tungsten showed a resistance to carbon deposition, whereas the reference Fe2O3 showed peaks of CO and CO2 during the oxidation period, thus indicating carbon deposition. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Industrial activities and unconscious consumption of natural resources cause environmental pollution with the rapid increase in the world population. As a result of the widespread use of iron oxide nanoparticles (Fe2O3 NP) with nano‐industrial activities, it is predicted that this NP will accumulate in the air, water, and soil. In the present study, the purpose was to find out the genotoxic effects on root meristem cells of the Triticum aestivum L. plant, which is an indicator organism exposed to 20–40 nm Fe2O3 NPs at different concentrations (100, 200, and 400 ppm). The amount of Fe2O3 NP accumulated in T. aestivum used in the study was determined with x‐ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), SEM element map, and EDS characteristic spectrum. All concentrations of Fe2O3 NP caused significant decreases in the mitotic index. Fe2O3 NPs significantly increased the frequency of mitotic abnormalities in T. aestivum root tip cells at all treatment times and all concentrations when compared to the control. Fe2O3 NPs were formed by various mitotic abnormalities such as loss of genetic material, deconstructed prophase, adhesion, chromosome groupings in metaphase, deconstructed metaphase, C‐Metaphase, chromosomal loss, chromosomal fracture, polyploidy, deconstructed anaphase, lagging chromosome, fragment, polar deviation, bridging, propagation, asynchronous division, star anaphase, multipolarity, and deconstructed telophase. All these results show that Fe2O3 NPs are genotoxic and clastogenic and may also cause DNA damage. Briefly, these data show that Fe2O3 NPs taken by organisms may pose a danger to the organism and the upper consumer. These findings also show that the production and use of Fe2O3 NPs, which affect organisms, must be controlled, and ultimately, be safely disposed of to reduce their bioaccumulation. Research Highlights: In the present study, the purpose was to find out the genotoxic effects on root meristem cells of the Triticum aestivum L. (bread wheat) plant, which is an indicator organism exposed to 20–40 nm Fe2O3 NPs at different concentrations (100, 200, and 400 ppm).The amount of Fe2O3 NP accumulated in T. aestivum used in the study was determined with x‐ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), SEM element map, and EDS characteristic spectrum.The mitotic index was calculated to reveal the genotoxic effect."Loss of genetic material, deconstructed prophase, adhesion, chromosome groupings in metaphase, deconstructed metaphase, C‐Metaphase, chromosomal loss, chromosomal fracture, polyploidy, deconstructed anaphase, lagging chromosome, fragment, polar deviation, bridging, propagation, asynchronous division, star Chromosomal abnormalities such as anaphase, multipolarity, and deconstructed telophase" were visualized.Fe2O3 NPs are genotoxic and clastogenic and may also cause DNA damage. [ABSTRACT FROM AUTHOR]

Iron making is the biggest single cause of global warming. The reduction of iron ores with carbon generates about 7% of the global carbon dioxide emissions to produce ≈1.85 billion tons of steel per year. This dramatic scenario fuels efforts to re‐invent this sector by using renewable and carbon‐free reductants and electricity. Here, the authors show how to make sustainable steel by reducing solid iron oxides with hydrogen released from ammonia. Ammonia is an annually 180 million ton traded chemical energy carrier, with established transcontinental logistics and low liquefaction costs. It can be synthesized with green hydrogen and release hydrogen again through the reduction reaction. This advantage connects it with green iron making, for replacing fossil reductants. the authors show that ammonia‐based reduction of iron oxide proceeds through an autocatalytic reaction, is kinetically as effective as hydrogen‐based direct reduction, yields the same metallization, and can be industrially realized with existing technologies. The produced iron/iron nitride mixture can be subsequently melted in an electric arc furnace (or co‐charged into a converter) to adjust the chemical composition to the target steel grades. A novel approach is thus presented to deploying intermittent renewable energy, mediated by green ammonia, for a disruptive technology transition toward sustainable iron making. [ABSTRACT FROM AUTHOR]

The purpose of this study was to modify bentonite (B) by iron using the solid‐phase ion exchange method to enhance the asphaltene adsorption. According to the scanning electron microscope (SEM) and x‐ray diffraction analysis (XRD) results, after solid‐state ion exchange, the structure of parent bentonite was changed slightly. An energy‐dispersive x‐ray analysis (EDX) showed that after ion exchange, the iron contents of bentonite increased from 0.6% to 1.6% w/w. Bentonite modification with iron increases asphaltene adsorption capacity (about 60%) compared to parent bentonite. Optimal adsorbent conditions for adsorption of asphaltene are 100 ppm concentration, 5 g/L adsorbent, and 60 min contact time. Adsorbent behavior showed that the adsorption kinetics and isotherm are in good agreement with the pseudo‐second‐order model and the Langmuir equation. [ABSTRACT FROM AUTHOR]

Accurate chronology of climatic shifts is critical to understand the controls on landscape and species evolution. Unfortunately, direct dating of continental climate change is hindered by the scarcity of dateable terrestrial products evidencing climatic shifts. Here we use ferruginous indurations from the arid landscapes of the Nullarbor Plain in southern Australia to constrain the timing of Plio‐Pleistocene aridification in the continental realm. We present (U‐Th)/He goethite data implying active induration processes between c. 2.7 and 2.4 Ma. Chemical‐mineralogical and petrographic examination suggests that formation of ferruginous indurations was linked with a decline of the groundwater table, driven by the rapid climatic shift from humid late Pliocene to arid early Pleistocene conditions. Combined with local to global climatic proxies, we conclude that ferruginous indurations are promising targets to obtain absolute ages on landscape evolution to refine continental climatic chronology and improve understanding of the environmental drivers of species diversification and extinction. Plain Language Summary: The reconstruction of Earth's climate record is typically founded on the physicochemical properties of marine sediments. Continental sediments that yield time‐constrained climate information are rare, but important to interpret wider Earth system responses and the co‐evolution of regional climate, landscape, and biota. This study presents direct dating of continental climate change on the Nullarbor Plain to constrain its development as an important biogeographic barrier driving species diversification between SW‐ and SE‐Australia. Age dating of iron‐oxide cements constrains the waning availability of mobile water (e.g., groundwater) and the onset of drier conditions related to global Plio‐Pleistocene climate change. These findings demonstrate that iron‐oxides may provide an excellent continental archive to anchor major climate shifts and help understand associated terrestrial ecosystem change. Key Points: (U‐Th)/He data from ferruginous indurations capture the onset of Plio‐Pleistocene aridification in southern AustraliaCorrelation of induration age with other climatic proxies indicates that ferruginous indurations track terrestrial water table evolutionTiming of aridification constrains evolution of important biogeographic barrier [ABSTRACT FROM AUTHOR]

The enhancement of the colloidal stability of magnetite nanoparticles (MNPs) for environmental-related fields has greatly attracted researchers' attention. This study used a high hydrophilic negatively charged polyelectrolyte, poly(4-styrenesulfonic acid co-maleic acid) sodium (PSAAS), to enhance the colloidal stability of MNPs. Coating of the naked MNPs with PSAAS polyelectrolyte is a simple and rapid method to obtain colloidally stable MNPs while sustaining the chemical reactivity of MNPs in water purification. The prepared PSAAS-coated MNPs were characterized by scanning electron microscope, energy dispersive X-ray, Fourier transform infrared, zeta potential analysis, transmission electron microscope and X-ray diffraction. Moreover, the colloidal stability and adsorption performance tests of these naked MNPs and PSAAS-coated MNPs (with different concentrations of PSAAS coated) were investigated and compared. PSAAS-coated MNPs with 0.001 g/ml PSAAS coating possessed the best colloidal stability and the highest methylene blue (MB) dye removal efficiency (94.53 ± 0.69%). The adsorption isotherm and kinetic studies for the adsorption of MB onto PSAAS-coated MNPs were well-described by the Langmuir model and pseudo-second-order kinetic model. These magnetic adsorbents, with high separation efficiency, simple and low production cost and recyclable property, are promising as practicable adsorbents in water treatment. [ABSTRACT FROM AUTHOR]

For strongly correlated metal oxides, several density functional theories have been used to describe the electronic structure of bulk iron oxide (α‐Fe2O3) and corresponding surfaces, including GGA+U and hybrid functionals (HSE), but the accuracy of these methods is unclear for these metal oxides. In the present study, first‐principles simulations were carried out to examine the effects of a hybrid density functional on α‐Fe2O3 bulk and surface slabs. Further, by using GGA+U, van der Waals corrections and O2 over binding corrections were also examined. It has been found that HSE functionals with 17.5 % Fock exchange predict better properties than those with 12 % or 25 % exchange. Methodological studies indicate that GGA+U predicted zero‐bandgap surface slabs become semiconducting slabs at HSE, and that calculated bandgaps are dependent on the actual exchange addition percentage. Our studies also show that the surface energy and relative stability of different Fe2O3 terminations are less sensitive to the inclusion of dispersion terms. However, when accounting for the GGA‐error in O2 over‐binding, significant changes occur in the computed surface energies. Additionally, HSE06 functional was tested on MnO2(0001) and MnO2(110) surfaces. Both surfaces were identified as metallic by a PBE+U calculation, and an HSE06 analysis revealed a nonzero band gap. [ABSTRACT FROM AUTHOR]

Electrocoagulation is an evolving technology for the abatement of a broad range of pollutants in wastewater owing to its flexibility, easy setup, and eco-friendly nature. Here, environment-friendly strategies for the separation, retreatment, and utilization of microplastics via electrocoagulation are investigated. The findings show that the flocs generated by forming Fe3O4 on the surface of polyethylene (PE) particles are easily separated using a magnetic force with high efficiency of 98.4%. In the photodegradation of the obtained flocs, it is confirmed that Fe3O4 shall be removed for the efficient generation of free radicals, leading to the highly efficient photolysis of PE. The removed Fe3O4 can be recycled into iron-oxalate compounds, which can be used in battery applications. In addition, it is suggested that heat treatment of Fe3O4-PE flocs in an Ar atmosphere leads to forming Fe3O4 core-carbon shell nanoparticles, which show excellent performance as anodes in lithium-ion batteries. The proposed composite exhibits an excellent capacity of 1123 mAh g-1 at the current density of 0.5 A g-1 after 600 cycles with a negative fading phenomenon. This study offers insight into a new paradigm of recyclable processes, from environmental issues such as microplastics to using energy materials. [ABSTRACT FROM AUTHOR]

Background: Persons with cosmetic tattoos occasionally experience severe pain and burning sensation on magnetic resonance imaging (MRI). Objective: To explore the culprit magnetic substances in commonly used permanent makeup inks. Material and methods: 20 inks used for cosmetic tattooing of eyebrows, eyeliners, and lips were selected. Ink bottles were tested for magnetic behavior with a neodymium magnet. Eight iron oxide inks qualified for the final study. Metals were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP‐MS). The magnetic fraction of inks was isolated and analyzed by X‐ray fluorescence (XRF). Magnetic iron compounds were characterized by Mössbauer spectroscopy and powder X‐ray diffraction (XRD). Results: ICP‐MS showed iron in all magnetic samples, and some nickel and chromium. Mössbauer spectroscopy and XRD detected ferromagnetic minerals, particularly magnetite, followed by goethite and hematite. Conclusion: This original study of cosmetic ink stock products made with iron oxide pigments reports magnetic impurities in inks for cosmetic tattooing, e.g., magnetite, goethite, and hematite. These may be the main cause of MRI burn sensation in cosmetic tattoos. The mechanism behind sensations is hypothesized to be induction of electrical stimuli of axons from periaxonal pigment/impurity activated by magnetic force. Magnetite is considered the lead culprit. [ABSTRACT FROM AUTHOR]

Purpose: In this study, we examine the effects of a recently developed, iron‐based coupling medium (IBCM) on guidance magnetic resonance (MR) scans during transcranial, magnetic‐resonance‐guided, focused ultrasound surgery (tMRgFUS) procedures. More specifically, this study tests the hypotheses that the use of the IBCM will (a) not adversely affect image quality, (b) remove aliasing from small field‐of‐view scans, and (c) decouple image quality from the motion state of the coupling fluid. Methods: An IBCM, whose chemical synthesis and characterization are reported elsewhere, was used as a coupling medium during tMRgFUS procedures on gel phantoms. Guidance magnetization‐prepared rapid‐gradient‐echo (MP‐RAGE), TSE, and GRE scans were acquired with fields of view of 28 and 18 cm. Experiments were repeated with the IBCM in several distinct flow states. GRE scans were used to estimate temperature time courses as a gel target was insonated. IBCM performance was measured by computing (i) the root mean square difference (RMSD) of TSE and GRE pixel values acquired using water and the IBCM, relative to the use of water; (ii) through‐time temperature uncertainty for GRE scans; and (iii) Bland–Altman analysis of the temperature time courses. Finally, guidance TSE and GRE scans of a human volunteer were acquired during a separate sham tMRgFUS procedure. As a control, all experiments were repeated using a water coupling medium. Results: Use of the IBCM reduced RMSD in TSE scans by a factor of 4 or more for all fields of view and nonstationary motion states, but did not reduce RMSD estimates in MP‐RAGE scans. With the coupling media in a stationary state, the IBCM altered estimates of temperature uncertainty relative to the use of water by less than 0.2°C. However, with a high flow state, the IBCM reduced temperature uncertainties by the statistically significant amounts (at the 0.01 level) of 0.5°C (28 cm field of view) and 5°C (18 cm field of view). Bland–Altman analyses found a 0.1°C ± 0.5°C difference between temperature estimates acquired using water and the IBCM as coupling media. Finally, scans of a human volunteer using the IBCM indicate more conspicuous grey/white matter contrast, a reduction in aliasing, and a less than 0.2°C change in temperature uncertainty. Conclusions: The use of an IBCM during tMRgFUS procedures does not adversely affect image quality for TSE and GRE scans, can decouple image quality from the motion state of the coupling fluid, and can remove aliasing from scans where the field of view is set to be much smaller than the spatial extent of the coupling fluid. [ABSTRACT FROM AUTHOR]

Iron oxide is commonly found in natural or industrial glass compositions and can exist as ferrous (Fe2+) or ferric (Fe3+) species, with their ratios depending on glass composition, temperature, pressure and the redox reactions during the glass forming process. The iron redox ratio plays an important role on silicate glass structures and consequently various properties. This work aims to study the effect of iron oxide, and particularly the iron redox ratio, on the structures of borosilicate and boroaluminosilicate glasses using molecular dynamics simulations with newly developed iron potential parameters that are compatible with the borosilicate potentials. The results provide detailed cation coordination states of both iron species and the effect of redox ratio on boron coordination and other structural features. Particularly, competition for charge compensating modifier cations (such as Na+) among the fourfold‐coordinated cations such as B3+, Al3+, and Fe3+ is investigated by calculating the cation–cation pair distribution functions and coordination preferential ratios. The results show that the trivalent ferric ions, with a shorter Fe–O bond distance and better defined first coordiation shell with mainly four‐fold coordination, act as a glass former whereas the divalent ferrous ions mainly play the role of glass modifier. The ferrous/ferric ratio (Fe2+/Fe3+) was found to affect the glass chemistry and hence glass properties by regulating the amount of four‐coordinated boron, the fraction of non‐briding oxygen and other features. The results are compared with available experimental data to gain insights of the complex structures and charge compensation schemes of the glass system. [ABSTRACT FROM AUTHOR]

The direct reduction of iron ore pellets with syngas or hydrogen is a promising technology to reduce the CO2 emissions of the iron and steel industry. The conversion rate of single iron ore pellets to iron is extensively investigated. In most of these studies, a shrinking core model is employed to reproduce the experimental observations. However, this model presents an inherent bias by assuming a sharp separation between a fully converted region and a fully unreacted one. Herein the present study, an improved porous solid model is proposed. This model solves the mass balances of the individual gas species and the solid ones assuming spherical symmetry. The governing equations, the main algorithm, and validation cases are presented. The present model also offers wide flexibility to incorporate complex phenomena such as porosity changes or carbon deposition. Furthermore, the proposed model is integrated into a computational fluid dynamics (CFD) environment. It is verified that identical input parameters yield almost identical results in both frameworks, opening the gate toward reliable CFD simulations of industrial‐scale reactors. [ABSTRACT FROM AUTHOR]

Magnetite nanoparticles (MNPs) are the most conventional type of iron oxide nanoparticles used in the food industrial processes, removal of heavy metals, and biomedical applications in vivo or in vitro. Until now, there is no sufficient information that can confirm its effect on the body's immune system and reproductive health in males. The purpose of this research is to estimate the immunotoxic and reproductive toxic effects of MNPs in male rats. This study included 36 adult male albino rats divided into three groups. The experimental groups were intraperitoneally injected with MNPs at doses of 5 and 10 mg/kg body weight 3 times/week for 60 days, while the control group was injected with saline solution. MNPs caused a significant decrease in the body weight change of the high‐treated group. MNPs produced changes in the lymphocyte proliferation rate which referred to a significant immunotoxic effect measured by the 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide reduction method. The testicular tissue of male‐treated rats showed some moderate and severe degenerative changes. The sperm parameters of count, motility, and viability were significantly decreased. Sperm morphological abnormalities were detected in all treated animals. MNPs produced a significant decrease in testosterone levels, increased the level of malondialdehyde, impaired the activity of the antioxidant enzymes and induced testicular DNA damage. In conclusion, MNPs affected the normal immune state in male rats and facilitated the generation of reactive oxygen species subsequently triggering testicular oxidative stress damages. All these consequences had a negative impact on male reproductive health. [ABSTRACT FROM AUTHOR]

Azo dyes, like Congo red (CR), are persistent contaminants that cause detrimental consequences on living organisms in various habitats. In the present study, a novel and facile one‐pot citric acid functionalized iron oxide magnetic nanoparticles (Fe3O4@CA NPs) through an electrochemical method are synthesized and characterized for adsorbing CR dye present in an aqueous solution is reported. The influence of various factors on the adsorption of CR dye, namely pH of the CR solution, Fe3O4@CA NPs concentration, initial CR dye concentration, contact time, temperature, and agitation speed, are examined. The adsorption isotherms and kinetic studies for CR adsorption on Fe3O4@CA NPs are also investigated. The equilibrium results correspond well to the Langmuir isotherm having maximum dye uptake of 46.948 mg g−1, while the adsorption follows the pseudo‐second‐order kinetics model. The adsorption process appears to be spontaneous and endothermic, according to the thermodynamic parameters. The mechanism of CR adsorption on Fe3O4@CA NPs is also suggested. The synthesized nanoadsorbent shows more than 90% recyclability during five consecutive adsorption–desorption cycles. The simple and cost effective synthesis, high adsorption capacity, and recyclable nature of Fe3O4@CA NPs suggest the potential to eliminate CR from aqueous sources. [ABSTRACT FROM AUTHOR]

BACKGROUND: At present, the volumes of use of electric arc furnace (EAF) dust are extremely insignificant. The volumes of their formation amount to thousands of tons per month. During storage, they have a negative impact on the environment. At the same time they are a material that has a valuable composition (oxides of iron, non‐ferrous metals, etc.) and is promising for recycling. However, the secondary use of zinc‐containing EAF dust in ferrous metallurgy leads to the accumulation of zinc in the lining of blast furnaces and frequent malfunctions. RESULTS: It has been established that zinc oxide is mainly in the bound state in the composition of the franklinite phase (Zn,Mn,Fe)(Fe,Mn)2O4. The processes of solid‐phase reduction of EAF dust with the production of zinc concentrate and sponge iron, which are in demand as raw materials for non‐ferrous and ferrous metallurgy, have been studied. The optimal conditions for the reduction process were determined and the physicochemical characteristics, granulometric and phase composition of the initial materials, and reduction products were investigated. CONCLUSIONS: It has been established that the use of a combination of reducing agents of different nature (coal coke and H2) during heat treatment at 1100 °C and cooling in a reducing medium (Ar/H2, 5 vol%) makes it possible to obtain sponge iron with impurities (the highest degree of iron metallization was 97.5%), and zinc oxide with a basic substance content of about 98.4 wt.%. © 2022 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

In this work, a green approach for the synthesis of graphene‐iron oxide nanocomposite (GINC) was followed. FTIR, Raman, XRD and SEM analysis tools were all used to characterize the synthesized nanocomposite. Furthermore, the Differential Scanning Calorimetry (DSC) method was used to investigate the GINC′s catalytic activity for the decomposition of a double base propellant (DBP). Kinetic characteristics for the thermal decomposition of DBP such as activation energy and frequency factor, were determined using iso‐conversional approaches, including Vyazovkin's nonlinear integral with compensatory effect (VYA/CE), iterative Kissinger‐Akahira‐Sunose (It‐KAS), and iterative Flynn‐Wall‐Ozawa (It‐FWO). Based on the results obtained from the kinetic analysis, the introduction of GINC has reduced the activation energy of the pristine DBP (approximately 230 kJ/mol) by 40 kJ/mol, showing that this addition has good catalytic activity on the thermal degradation of DBP. Additionally, the results showed that the critical ignition temperature is augmented from 187.1 to 199.6 °C, when DBP is doped with 3 % GINC highlighting the fact that GINC enhanced the thermal safety of DBP. [ABSTRACT FROM AUTHOR]

Due to the increased incidence and population growth that has been leading to growing number of cases worldwide, early diagnosis and treatment of cancer is crucial. Low density cancer tissue cannot be diagnosed before progressing toward a metastatic stage. Thus, theranostic systems play a significant role in assisting timely diagnosis and treatment. The combination of magnetic resonance imaging (MRI) and computed tomography (CT) contrast agents in a single probe is of high importance and necessity, where individual strengths of each approach can be merged while shortcomings of each modality could be compensated. With this motivation, we have developed and synthesized Bi2S3@BSA‐Fe3O4 nanoparticles as a dual MRI/CT contrast agent and carrier of curcumin (CUR) as natural anticancer drug. The nanoparticles shortened both the longitudinal (T1) and transverse (T2), MRI relaxation times, with a more distinct effect on producing negative contrast (T2) images with a relaxivity (r2) of 54.73 mM−1 s−1. The magnetite/bismuth hybrid nanoparticle also was capable of increasing CT image contrast. Further, in vitro cytotoxicity assay showed high biocompatibility of the synthesized nanoparticles. Furthermore, in vitro cytotoxicity assay on cancer cells showed high anticancer activity of the synthesized nanoparticles. [ABSTRACT FROM AUTHOR]

BACKGROUND: Arsenic is one of the most serious drinking water contaminants around the world. The development of iron oxide materials, including nanoparticles, as sorbents for arsenic remediation has shown promising results in recent years. Some of these materials are already used as commercial‐grade arsenic sorbents. However, the use of iron‐oxide nanoparticles (IONPs) has barely been used in real‐world conditions. This work compares commercial IONPs with three proven arsenic sorbents. RESULTS: The full chemical characterization includes electron microscopy, X‐ray diffraction and X‐ray photon spectroscopy to determine morphology, crystalline structure and elemental analysis, respectively. Arsenic remediation studies also were conducted in both batch and column set‐ups with real water samples from Salamanca, Mexico. The conditions (pH 8, high concentration of silica and presence of other interferences) found in this site are outside the recommended parameters of operations for most of the arsenic sorbents. All of the materials observed a negative effect because of silica presence. However, the effects observed in batch did not correlate directly to the column tests. This is important when evaluating the viability of using sorbents in specific conditions. CONCLUSIONS: A feasibility analysis revealed that some commercial sorbents can treat water with the conditions presented in the selected site, but the cost of treatment is not viable for developing countries. In addition, the generated waste by using these sorbents would be substantial. These challenges could be diminished by using nanoparticles, yet the commercially‐available IONPs do not fill this gap. Better designed nanomaterials are still needed for arsenic removal. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Current environmental restrictions, such as the zero liquid discharge policy, require developing new methods to completely remove micropollutants from wastewater. Non‐steroidal anti‐inflammatory drugs (NSAID) are major component of such pollutants. The adsorptive removal of ketoprofen (KP), a widely prescribed NSAID, was studied using a newly synthesized magnetic adsorbent. The maximum adsorption capacity was determined to be 39.2 mg/g with almost 98 % removal for 50 mg/L KP at neutral pH. The adsorption of KP was found to be pH dependent and more efficient in acidic media. The isothermal behavior of the adsorbent followed a sigmoidal behavior and was best fitted to the corresponding‐states equation (CSE). The adsorption was found to follow second‐order kinetics with a half‐life of 4.4 min. The adsorption was also found to be exothermic and therefore it is favorable at low temperatures. The study also showed that the adsorbent can be regenerated for several adsorption‐desorption cycles. The adsorption mechanism was also explored by state‐of‐the‐art periodic quantum theoretical calculations. [ABSTRACT FROM AUTHOR]

How does the cerium (Ce) doping in ferrimagnetic magnetite (Fe3O4) affect the crosslinking state and kinetics of epoxy crosslinking with amine curing agents? To answer this question, we electrochemically synthesized nanoparticles of Ce–Fe3O4 and characterized them by FTIR, XRD, FE‐SEM, EDX, TEM, and XPS analyses. The presence of Ce atoms in Fe3O4 crystalline lattice increased the surface area and active hydroxyl sites of the prepared magnetic nanoparticles (MNPs) associated with partial shrinkage of molecular lattice. The MNPs uniformly dispersed in epoxy resin and unconditionally tagged epoxy nanocomposites as Excellent cured systems. The effect of lanthanide doping on the cure kinetics of epoxy with amine was explored applying nonisothermal DSC and model‐free kinetic approaches, signifying that Ce–Fe3O4 nanoparticles facilitated epoxy ring opening by intensification of etherification reaction whatever the heating rate. Even at very low loading of Ce–Fe3O4 nanoparticles into the epoxy (0.1 wt.%), the average apparent activation energy significantly decreased by ≈10%. This outcome would highlight the role of crosslinking on the ultimate properties, such as anticorrosive and/or self‐healing characteristics contributed by Ce‐doped nanoparticles once added to epoxy coating formulation. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) is a key energy conversion process, which is critical for the efficient operation of fuel cells and metal–air batteries. Here, we report the significant enhancement of the ORR‐performance of commercial platinum‐on‐carbon electrocatalysts when operated in aqueous electrolyte solutions (pH 5.6), containing the polyoxoanion [Fe28(μ3‐O)8(L‐(−)‐tart)16(CH3COO)24]20−. Mechanistic studies provide initial insights into the performance‐improving role of the iron oxide cluster during ORR. Technological deployment of the system is demonstrated by incorporation into a direct formate microfluidic fuel cell (DFMFC), where major performance increases are observed when compared with reference electrolytes. The study provides the first examples of iron oxide clusters in electrochemical energy conversion and storage. [ABSTRACT FROM AUTHOR]

Soils have distinctive chemical, physical, mineralogical and biological properties, which make it possible to differentiate them in different environments and also to test for an association of a particular questioned item with a crime scene. Mineral compositions and structures in the soil clay fraction can reflect a distinct characteristic when analyzed by powerful techniques. In this way, the aim of this study was to compare the discriminative power of Fe‐oxides concentrated clay samples from the same soil class with and without differences in parent material when analyzed using the Rietveld method and two sources of X‐ray diffraction: conventional and high‐resolution synchrotron radiations. Clay samples were Fe concentrated (kaolinite and gibbsite removal) to clarify mineralogical composition of 12 samples from three simulated crime scenes, developed under claystone and granite. By Rietveld refinement, detailed crystallographic data were obtained to discriminate samples according their provenance. By synchrotron radiation, mineral data demonstrated the power of quantitative (crystallite size and minerals contents) and qualitative (identification of majoritarian and accessory minerals) analysis by Rietveld refinement, which provides well‐resolved data able to discriminate samples from different and same geology. The techniques can be applied in other criminal investigations given their potential of discrimination. [ABSTRACT FROM AUTHOR]

Ostwald ripening is a well‐known physicochemical phenomenon in which smaller particles, characterized by high surface energy, dissolve and feed the bigger ones that are thermodynamically more stable. The effect is commonly observed in solid and liquid solutions, as well as in systems consisting of supported metal clusters or liquid droplets. Here, evidence is provided for the occurrence of Ostwald ripening in an oxide‐on‐metal system which, in this case, consists of ultrathin iron monoxide (FeO) islands grown on Ru(0001) single‐crystal support. The results reveal that the thermally‐driven sintering of islands allows altering their fine structural characteristics, including size, perimeter length, defect density and stoichiometry, which are crucial, for example, from the point of view of heterogeneous catalysis. [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]

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]

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]

Iron oxide nanoparticles (Fe2O3 NPs) is the main component of air pollution particles in urban rail transit environment. People are more exposed to Fe2O3 NPs, however, the studies on relationship between Fe2O3 NPs and respiratory health are limited. In the present study, acute airway inflammation caused by Fe2O3 NPs and its possible mechanism were investigated. BALB/c mice were intratracheally challenged with different concentrations of Fe2O3 NPs. Fe2O3 NPs induced bronchial epithelial barrier function damage, infiltration of neutrophils and lymphocytes into the airway submucosa, secretion of mucus in the airway epithelium and elevated expression of eosinophil major basic protein (EMBP) in lungs. Compared with the control group, Fe2O3 NPs increased eosinophils by 20 times in bronchoalveolar lavage fluid (BALF), and markedly increased eosinophils related cytokines and chemokines, including interleukin (IL) ‐5, IL‐33, thymic stromal lymphopoietin (TSLP), monocyte chemotactic protein (MCP)‐3, eotaxin, tumor necrosis factor (TNF)‐α, keratinocyte chemoattractant (KC). Furthermore, Fe2O3 NPs up‐regulated levels of IL‐5, MCP‐3, eotaxin, and KC in serum. In vitro studies showed that Fe2O3 NPs increased the genes and proteins expression of Toll‐like receptors (TLR)‐2, TLR4, TNF receptor associated factor 6 (TRAF6), myeloid differentiation factor 88 (MyD88), nuclear factor (NF)‐κB, and TNF‐α in RAW267.4 cells. The downstream inflammatory cytokine protein expression and release such as TNF‐α was significantly decreased after using TLR2/TLR4 inhibitor OxPAPC, but not MyD88 inhibitor ST2825. These results suggest that TLR2 and TLR4 played important role in Fe2O3 NPs inducing acute eosinophilic airway inflammation in the murine lung. [ABSTRACT FROM AUTHOR]

BACKGROUND In this study, polyethersulfone (PES) hollow fiber membranes incorporated with surface‐functionalized iron oxide (Fe3O4) nanoparticles were developed in order to improve water flux and antifouling properties of PES membrane. Commercial Fe3O4 nanoparticles was coated by polydopamine (PDA), followed by functionalization using (3‐aminopropyl)triethoxysilane (APTES) and sulfonic acid to produce Fe3O4/PDA‐Amine and Fe3O4/PDA‐Sulf nanoparticles, respectively. All the nanoparticles‐modified membranes were synthesized using dope solution composed of different nanoparticles, followed by a series of instrumental characterization and filtration assessments. RESULTS: It is found that the membrane incorporated with Fe3O4/PDA‐Amine exhibited the best filtration performance, achieving water flux of 137.23 L m−2 h−1 bar−1 and bovine serum albumin (BSA) rejection of 92.16%. As a comparison, the pristine PES membrane only showed 82.60 L m−2 h−1 bar−1 and 71.92%, respectively. The membrane with Fe3O4/PDA‐Sulf also showed lower performance, recording 129.88 L m−2 h−1 bar−1 and 88.39%, respectively. The improved performance of the Fe3O4/PDA‐Amine‐modified PES membrane could be attributed to its lowest water contact angle (65.10°), highest porosity (68.14%), ideal pore size (65 nm) as well as good structural integrity. More importantly, the improved surface properties also led to outstanding fouling resistance, achieving flux recovery rate of 97%. This membrane also achieved excellent chemical oxygen demand (95.17%) and color (89.86%) reduction when tested using river water sample. CONCLUSION: Our work demonstrated a simple approach to functionalize the surface of Fe3O4 nanoparticles and showed the effectiveness of the surface‐functionalized Fe3O4 nanoparticles in improving not only the surface properties of PES membrane but also its filtration performance in terms of permeability, rejection and antifouling property. © 2021 Society of Chemical Industry (SCI). [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]

The effect of iron oxide nanoparticles (Fe2O3 NPs) content on the structural and optical parameters of polyvinyl alcohol/graphene (PVA/G) blend has been investigated. Fe2O3 NPs were synthesized by the hydrothermal procedure. Nanocomposite (NC) films of PVA/G filled with different amounts of Fe2O3 NPs were equipped using the solution casting technique. The surface morphology, structural, and optical properties were examined by scanning electron microscope (SEM), X‐ray diffraction (XRD), and ultraviolet‐visible‐near‐IR (UV‐Vis‐NIR) spectrophotometry techniques, respectively. SEM micrographs reveal the homogenous distribution of Fe2O3 NPs in the PVA/G matrix. The XRD analysis exhibits the formulation of the hematite phase of Fe2O3 NPs and the semi‐crystalline nature of PVA/G NC films. The UV‐Vis‐NIR data analysis shows that the optical properties of the PVA/G blend could be tailored via Fe2O3 NPs filling. Wemple–DiDomenico model is utilized to explore the dispersion parameters of the prepared NCs. A significant effect of Fe2O3 NPs filling is realized on the oscillator and dispersion energies, infinite refractive index, dielectric constant, average oscillator strength and the lattice dielectric constant of the NC films. PVA/G filled Fe2O3 NPs are suggested for different optical and storage applications. [ABSTRACT FROM AUTHOR]

The possibility to arrange and embed magnetic micro‐ and nanoparticles in thin polymer film systems using flat magnetically patterned substrate templates is investigated. In contrast to self‐organized particle rows forming by applying a homogeneous magnetic field, particles adapt to the magnetic field landscape of the substrate's magnetic pattern prior to polymer crosslinking. Crosslinking then fixes the particle positions in the polymer. The process is tested for composites of hydrophobic polydimethylsiloxane (PDMS) and maghemite nanoparticles as well as for hydrophilic polyvinyl alcohol (PVOH) and hydrophilic functionalized, superparamagnetic core–shell microspheres. The substrate template is an exchange bias layer system magnetically patterned into parallel‐stripe domains with in‐plane magnetizations and head‐to‐head/tail‐to‐tail remanent magnetization orientation in adjacent magnetic domains. A high occupancy percentage of magnetic beads on a domain wall as well as anisotropic actuation of the composite is achieved. [ABSTRACT FROM AUTHOR]

The nano‐sized bush‐like α‐Fe2O3 particles were synthesized using sol‐gel auto combustion route. The structural characterization of obtained α‐Fe2O3 was performed by X‐ray diffraction (XRD) method to confirm its phase and crystallinity. The Scanning Electron Microscopy (SEM) confirmed the formation of bush‐like nanostructure which was further used for the electrochemical charge storage performance testing. The electrochemical performances of the synthesized electrode material were studied by using Cyclic Voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analysis in a three electrode configuration. The variation of specific capacitance values with the different molar concentration of electrolyte has been discussed. An enhancement in the specific capacitance has been observed up to 3 M KOH electrolyte solution. The maximum value of specific capacitance is 202.2 F g−1 which is obtained at a scan rate of 2 mV s−1 for 3 M aqueous KOH solution as electrolyte. [ABSTRACT FROM AUTHOR]

We fabricated iron oxide particles from iron(III) nitrate in a liquid flame spray synthesis. Unlike in most liquid flame spray studies, we implemented a secondary oxygen flow. The effect of the gas flow setup and two additives to the precursor solution, oxalic acid and citric acid, on the resulting particles was studied, with the focus on crystallographic phase composition. The synthesis yielded either pure maghemite or maghemite/hematite mixed phase powders. For solutions without additives, the maghemite fraction was almost linearly dependent on the equivalence ratio. The specific surface area was highest for the smallest equivalence ratios, then decreased, and increased again for the highest values. Some variation was observed between samples with equal equivalence ratios but the total oxygen flow divided differently between the two oxygen channels, a higher atomization flow promoting larger hematite fraction, and higher specific surface area. Both additives reduced the amount of hematite in the powder samples, citric acid being the more efficient one. Citric acid slightly raised the specific surface area, whereas oxalic acid dropped it in half. [ABSTRACT FROM AUTHOR]

Herein, we report a new and efficient method for preparing Fe3O4@SiO2@WO3 core@dual shell nanocatalysts featuring enhanced catalytic activity for the oxidative cleavage of the oleic acid double bond and fast magnetic separation. Various characterization techniques including EDS, XPS, SEM, and advanced elemental HRTEM mapping were used to characterize this type of magnetic core@dual shell nanocatalysts. The obtained core@shell structure is composed of a central magnetite core with a strong response to external fields, an interlayer of SiO2, and an outer layer of WO3 nanocrystals. This core@shell nanocatalyst exhibited higher catalytic activity than reported tungsten based heterogenous catalysts for the oxidative cleavage of the oleic acid double bond. The presence of the SiO2 interlayer prevents any deterioration of the catalytic efficiency of the WO3 nanocrystal shell as well as the chemical and thermal stability of the Fe3O4 core. This nanocatalyst can be easily recycled by applying an external magnetic field while maintaining its catalytic activity during at least three cycles of use. [ABSTRACT FROM AUTHOR]