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Iron oxide has been widely studied in chemical looping hydrogen generation (CLHG) process as an oxygen carrier, but fast decline of its activity in redox cycles due to sintering and agglomeration is one of the main drawbacks. In this work, the colloidal crystal templated (CCT) method was applied to synthesize Fe 2 O 3 /CeO 2 oxygen carrier and the mole ratio of Fe/Ce was 8:2, aiming to inhibit adjacent grains from agglomerating and improve the contact between the fuel gas and the oxygen carrier. The redox performances were evaluated with CO as fuel in a batch fixed bed reactor for 20 redox cycles, with oxygen carriers prepared by co-precipitation (CP) and sol-gel (SG) methods as references. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), and H 2 -temperature programmed reduction (H 2 -TPR) were used for characterization. The results showed that the calcination temperature lower than 750 °C was suitable for the CCT. The redox experiments showed that the H 2 yield and the redox stability for the oxygen carrier prepared by CCT were higher than those by co-precipitation and sol-gel methods. The H 2 yield of CCT oxygen carrier kept stable from the 3rd cycle and was 8.5 mmol/gOC in the 20th cycle. The pore structures resulting from CCT were different from another two oxygen carriers before and after the cycles, but maintained well through SEM images, leading to high activity and stability during redox cycles. The crystallite sizes of Fe 2 O 3 and CeO 2 before and after redox cycles were the smallest for the CCT oxygen carrier from XRD patterns. In addition, H 2 -TPR demonstrated that CCT oxygen carrier exhibited the highest reactivity. • Colloidal crystal templated (CCT) is desirable for Fe 2 O 3 /CeO 2 preparation in CLHG. • The calcination temperature lower than 750 °C was suitable for the CCT. • The superior performance of CCT oxygen carrier can be ascribed to its pore structure. • The H 2 yield of the CCT oxygen carrier was 8.5 mmol/gOC after 20 cycles. [ABSTRACT FROM AUTHOR]

The presence of wear debris in sliding contacts is often regarded as detrimental, since it can increase friction, induce abrasive wear, reduce actual lubricant film thickness and compromise lubrication systems. On the other hand, the presence of debris may be fundamental to the formation of a protective tribolayer, which can reduce friction and wear. This work investigates the effect of the presence of different iron oxides (F 2 O 3 and Fe 3 O 4) with different sizes on the unlubricated reciprocating sliding of tool steels. For that, sliding tests were carried out with and without the addition of iron oxides. The addition of Fe 3 O 4 particles (larger and softer) resulted in friction (15%) and wear (95%) reduction. Two main factors seem to be responsible for friction and wear reduction when Fe 3 O 4 particles were added into the contact. The first is the relative hardness of the debris in relation to the materials in contact. Since they are softer than the specimens and the counter bodies, they do not cause their severe abrasive wear, which is much more significant for the harder F 2 O 3 particles. The second is the relative size (RS) between the debris and the specimen surface topography. When RS is small, the debris get entrapped in the valleys of the specimen topography, thus not participating in the contact. On the other hand, for larger values of RS , the debris become active and therefore can participate in the formation of a protective tribolayer. • Dry reciprocating sliding tests were carried out with and without the addition of F 2 O 3 and Fe 3 O 4. • The presence of iron oxide particles improved tribological behaviour reducing friction and wear. • The addition of Fe 3 O 4 particles (larger and softer) resulted in friction and wear reduction. [ABSTRACT FROM AUTHOR]

The importance of atherosclerosis is driving research to create improved diagnostic tools based on molecular imaging. Pretargeted imaging is the use of bioorthogonal probes that selectively accumulate upon reaction with a pre-modified biomolecule in vivo. To date, this very promising approach has not been applied to atherosclerosis. Neither has been the use of a single nano-radiomaterial for PET / T 1 -MR imaging of atherosclerosis. Here, we synthesized bioorthogonal nano-radiomaterials for in vivo pretargeted molecular imaging in a mouse model of atherosclerosis. Based on tetrazine-ligation, these functionalized 68Ga iron oxide nano-radiomaterials provide simultaneous PET and T 1 -MRI signals and selectively accumulate in atherosclerotic plaques in mice sequentially injected with trans-cyclooctene-modified antibodies against oxidized LDL followed by the hybrid nano-radiomaterial. Our results demonstrate the ability of this approach to unambiguously detect atherosclerosis. Furthermore, we show the first example of how hybrid imaging can be used for pretargeted bioorthogonal molecular imaging with nanomaterials. Unambiguous detection of atherosclerosis by the in vivo reaction of 68Ga iron oxide nanoparticles with anti-oxidized phospholipids antibody. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract Composites of antimony metal, iron oxide, and carbon black are attractive for use as lithium ion battery anodes when high rate charging is required. The large capacity of such a composite, together with a voltage that is intermediate between lithium titanate and graphite, makes it possible to address the typical trade-off between high energy density and safe operation in high power conditions. In this work, a variety of mechanical homogenization processes are investigated. A minimum threshold of energy input per unit mass during milling is required to produce a sufficiently homogeneous microstructure, which is required for stable electrochemical performance. The surface area of the processed material is found to be a useful method for quantifying the degree of homogeneity in the composite and is well correlated to the electrochemical performance. This understanding enables simplified scaling on larger volume manufacturing assets. Graphical abstract Image 1 Highlights • An anode is made from a composite of antimony, iron oxide, and carbon. • Increased homogeneity creates longer cycle lifetimes in an electrochemical cell. • A minimum threshold of energy per unit mass during milling is required. • The BET surface area is inversely related to the cycling stability for this composite. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Magnetic nanomaterials were formed by pulsed laser ablation of iron in water and air. • Material ablated in water contained spherical particles of Fe 3 O 4 , Fe 2 O 3 , FeO and Fe. • Material ablated in air contained more Fe 3 O 4 and nitrogen (N-O, N-H or FeN x) • The surface composition and electrokinetic properties of the materials differed. • Material obtained in air is more stable in colloids due to its surface composition. Abstract Magnetic nanomaterials were synthesized using a method of pulsed laser ablation of an iron target in water (PLAL) and in air (PLAG). The microstructure and composition of the obtained materials differed. Spherical nanoparticles (NPs) of 2–80 nm containing Fe 3 O 4 , α-Fe 2 O 3 , γ-Fe 2 O 3 , FeO and Fe were obtained using PLAL. According to the XPS and FTIR data, the surfaces of these particles contained both Fe 3 O 4 and Fe 2 O 3. PLAG led to the formation of NPs of 2–120 nm and 2-D lamellar structures up to 1 μm. This material contained more magnetite and nitrogen species, presumably iron nitrides. This material's surface contained FeOOH; the OH-group content was very high. It exhibited the greatest sedimentation stability and zeta potential value, while magnetic NPs (MNPs) obtained in water were less stable in colloids. The difference in the magnetic parameters of the two materials can be connected to not only the different composition (different magnetite content and nitrogen species presence) but also their structural features. Thus, PLAL and PLAG methods allowed for obtaining magnetic nanostructured materials with different characteristics suitable for application in different fields. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The engineering of iron oxide nanoparticles (IONPs) for biomedical use has received great interest over the past decade. In the present study we investigated the biocompatibility of IONPs grafted with linear (2P) or generation 1 (2PG1) or 2 (2PG2) dendronized oligoethyleneglycol units in THP-1-derived macrophages. To evaluate IONP effects on cell functionality and homeostasis, mitochondrial function (MTT assay), membrane permeability (LDH release), inflammation (IL-8), oxidative stress (reduced glutathione, GSH), NLRP3 inflammasome activation (IL-1β) and nanoparticle cellular uptake (intracellular iron content) were quantified after a 4-h or 24-h cell exposure to increasing IONP concentrations (0–300 µg Fe/mL). IONPs coated with a linear molecule, NP10COP@2P, were highly taken up by cells and induced significant dose-dependent IL-8 release, oxidative stress and NLRP3 inflammasome activation. In comparison, IONPs coated with dendrons of generation 1 (NP10COP@2PG1) and 2 (NP10COP@2PG2) exhibited better biocompatibility. Effect of the dendritic architecture of the surface coating was investigated in a kinetic experiment involving cell short-term exposure (30 min or 1 h 30) to the two dendronized IONPs. NP10COP@2PG2 disrupted cellular homeostasis (LDH release, IL-1β and IL-8 secretion) to a greater extend than NP10COP@2PG1, which makes this last IONP the best candidate as MRI contrast or theranostic agent. [ABSTRACT FROM AUTHOR]

Abstract The influence of 0.01–2 mol% Fe 2 O 3 powder addition on the microstructure, mechanical and optical properties, and hydrothermal stability of highly-translucent 3Y-TZP ceramics is assessed and compared with commercially available co-precipitated 0.18 mol% Fe 2 O 3 doped ZrO 2 powder-based ceramics. Only those ceramics with up to 0.1 mol% Fe 2 O 3 resulted in a proper shade for dental zirconia ceramics, with a typical composition of 87 vol% t -ZrO 2 and 13 vol% c -ZrO 2. The amount of cubic phase increased at higher Fe 2 O 3 content. The hardness (∼13 GPa) and fracture toughness (∼3.6 MPa m1/2) of the 0.01 mol% - 0.1 mol% Fe 2 O 3 doped 3Y-TZP was comparable, whereas the hardness decreased above 0.5 mol% Fe 2 O 3 and the fracture toughness decreased above 2 mol% Fe 2 O 3. The hydrothermal ageing resistance slightly increased for Fe 2 O 3 concentrations up to 1 mol%, whereas the translucency slightly decreased with increasing Fe 2 O 3 content. [ABSTRACT FROM AUTHOR]

Abstract A mechanochemical protocol was applied to the synthesis of a magnetic material based on iron oxide nanoparticles and Al-SBA-15. Full characterization of the prepared Fe 2 O 3 /Al-SBA-15 evidenced the effective functionalization of the aluminosilicate surface. Particularly, TEM analysis revealed that the mechanochemical protocol did not considerable affect the hexagonal ordered structure of Al-SBA-15. DRIFT experiments of Fe 2 O 3 /Al-SBA-15 showed interesting acidic properties, which can be further associated to a good catalytic performance. The catalytic behavior of the prepared material was tested in the oxidation of vanillyl alcohol to vanillin, displaying an excellent activity and selectivity. The material resulted to be highly stable in the aforementioned reaction, without considerable decrease of conversion after 10 reuse cycles. Graphical abstract Unlabelled Image Highlights • Simple mechanochemical synthesis of Fe 2 O 3 /Al-SBA-15. • Efficient oxidation of vanillyl alcohol to vanillin. • Highly active oxidation catalysts (>99% conversion, 88% selectivity). • Stable mechanochemical systems with almost full initial activity after ten reuses. [ABSTRACT FROM AUTHOR]

Abstract Magnetic nanoparticles (MNP) have been developed in the recent years for various applications like cell separation, immunoassay, and drug delivery. The present study involves the synthesis of stable, biocompatible Iron oxide MNP by coprecipitation of ferric chloride and ferrous chloride with Polyethylene glycol (PEG) as a surfactant to coat the nanoparticles twice. Scanning electron microscopic (SEM) images confirm the formation of uniform MNPs of size 12–17 nm. The peak at 582.2 cm−1 in the Fourier transform infrared spectrum (FTIR) corresponds to the Fe–O bond and the peak at 1104.1 cm−1 corresponds to a characteristic peak of PEG binding to the iron core. Tumor tissues selectively targeted with MNPs when placed in a magnetic field increases the temperature of the tumor tissues. The phantom study shows that there is a minimum of 1.3 °C and a maximum of 6.7 °C rise in temperature with increasing concentration of the nanoparticles embedded in the phantoms; this proved the possibility of enhancement of thermal images using MNPs and its usage for thermal ablation of cancer. MNPs can also be used as a contrast agent for magnetic resonance imaging (MRI). [ABSTRACT FROM AUTHOR]

Abstract Background Site-specific multimodal nanoplatforms with fluorescent-magnetic properties have great potential for biological sciences. For this reason, we developed a multimodal nanoprobe (BNPs-Tf), by covalently conjugating an optical-magnetically active bimodal nanosystem, based on quantum dots and iron oxide nanoparticles, with the human holo-transferrin (Tf). Methods The Tf bioconjugation efficiency was evaluated by the fluorescence microplate assay (FMA) and the amount of Tf immobilized on BNPs was quantified by fluorescence spectroscopy. Moreover, relaxometric and fluorescent properties of the BNPs-Tf were evaluated, as well as its ability to label specifically HeLa cells. Cytotoxicity was also performed by Alamar Blue assay. Results The FMA confirmed an efficient bioconjugation and the fluorescence spectroscopy analysis indicated that 98% of Tf was immobilized on BNPs. BNPs-Tf also presented a bright fluorescence and a transversal/longitudinal relaxivities ratio (r 2 / r 1) of 65. Importantly, the developed BNPs-Tf were able to label, efficiently and specifically, the Tf receptors in HeLa cells, as shown by fluorescence and magnetic resonance imaging assays. Moreover, this multimodal system did not cause noteworthy cytotoxicity. Conclusions The prepared BNPs-Tf hold great promise as an effective and specific multimodal, highly fluorescent-magnetic, nanoplatform for fluorescence analyses and T 2 -weighted images. General significance This study developed an attractive and versatile multimodal nanoplatform that has potential to be applied in a variety of in vitro and in vivo studies, addressing biological processes, diagnostic, and therapeutics. Moreover, this work opens new possibilities for designing other efficient multimodal nanosystems, considering other biomolecules in their composition able to provide them important functional properties. Graphical abstract Unlabelled Image Highlights • Transferrin (Tf) was efficiently conjugated to bimodal nanoparticles (BNPs). • BNPs-Tf presented high fluorescence and transversal relaxivity. • BNPs-Tf labeled efficiently cell Tf receptors by fluorescence /relaxometric assays. • BNPs-Tf did not cause significant toxicity in HeLa cells, under the conditions applied. • BNPs-Tf hold great promise for fluorescence analyses and T 2 -weighted images. [ABSTRACT FROM AUTHOR]

Today, one of the most important global tasks is the treatment of waste water from various pollutants, including heavy metal. Adsorption is a promising method of wastewater treatment in terms of efficiency and cost. In this paper, the Al/Fe oxide-oxyhydroxide composite powders, prepared by hydrothermal method using metal sulfate solutions and urea as precursors, are investigated as adsorbents for chromium. The influence of the [Al 3+ ]:[Fe 3+ ] ratio on the phase composition, textural properties, morphology, and thermal effects of composites was also investigated. It is shown that the maximum specific surface area (190 m 2 /g) is reached for samples synthesized from solutions with [Al 3+ ]:[Fe 3+ ] = 1:0 and 1:1. Cr(VI) adsorption from solutions was performed under static (batch adsorption) and dynamic (column adsorption) conditions. It is shown that the presence of sulfate ions on the surface of Al-containing samples suppresses the Cr(VI) adsorption. The maximum adsorption capacity in batch adsorption (3.66 mg/g) has a sample synthesized from solutions with [Al 3+ ]:[Fe 3+ ] = 1:6, which is characterized by a high (but not maximal) surface area (102 m 2 /g), a low content of sulfates and maximum zeta potential. Sorption experiments showed that the mean free adsorption energy is below 8 kJ/mol for all samples, indicating the adsorption process as the physical in nature and suggesting the possibility of Cr(VI) desorption and adsorbent regeneration. Based on the results of fixed-bed adsorption experiments, an atypical form of breakthrough curves is noted, as well as an increase in sorption capacity of about 4–5 times as compared with batch adsorption. [ABSTRACT FROM AUTHOR]

Platinum (Pt) electrodes modified with iron (Fe) have been used as electrocatalysts to split water, to reduce oxygen, and to oxidize methanol. The current study employed cyclic voltammetry and in situ scanning tunneling microscopy (STM) to probe the redox chemistry and spatial structure of an iron hydroxide thin film adsorbed on an ordered Pt(111) electrode in pH 3 sulfate solution (1 mM H 2 SO 4 + 0.1 M K 2 SO 4) containing 10 mM FeSO 4. The Pt(111) electrode was pretreated with the conventional annealing-and-quenching method, which resulted in a sub-monolayer native oxide. After this native oxide was stripped off, the adsorption of Fe2+ ions and the reduction of oxygen concurred to yield an ordered FeOH film on the Pt(111) electrode. In situ STM imaging revealed a unique spoke – wheel (SW) structure between 0.1 and -0.1 V (vs. Ag/AgCl). As opposed to the hexagonal FeO(111) bilayer structure observed on Pt(111) in the vacuum, a distorted hexagonal adlattice was seen with this SW pattern. Shifting the potential positively and negatively resulted in transformations of the SW structure into distorted moiré patterns. The same STM experiment performed with Fe 2 (SO 4) 3 led to a disordered film, indicating that ferrous, not ferric, ions were orderly adsorbed on the Pt(111) electrode. The role of anion in the formation of the FeOH film on the Pt(111) electrode was also conducted in pH 3 chloride solution (1 mM HCl + 0.1 M KCl + FeCl 2). [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The nanoparticles synthesized using Terminalia catappa leaf extract gave a mixture of Fe 2 O 3 and Fe 3 O 4 nanoparticles. • Cytotoxic behavior of the synthesized nanoparticles showed attack on both the normal (HEK 293) and cervical carcinoma (Hela) cell lines. • The effectiveness of nanoparticles towards anticancer properties depends of reaction conditions. In this research, iron oxide nanoparticles were synthesized by plant-mediated method. Their optical nature, crystallinity, composition, microscopy and sizes were characterized using energy dispersive X-ray, X-ray diffraction (XRD), scanning electron microscopy and transmission electron microscopy. The microscopic studies revealed spherical/polygonal morphologies with average particle size of 19.14 nm. The in-vitro cytotoxic analysis of the nanoparticles against HEK 293 normal cell lines and Human cervical (Hela) cell lines showed cell toxicity with IC 50 values 44.12 μg and 34.94 μg respectively. The antimicrobial tests showed sensitivity to some micro-organisms whereas some were resistant. In general, the nanoparticles displayed broad spectrum activity with Methicillin Resist Staphaureus (MRSA) showing the greatest growth inhibition. [ABSTRACT FROM AUTHOR]

The occurrence of agglomeration due to particle sintering is one of the most significant technical issues hindering the direct reduction process of iron oxide fines (DRI) in a high-temperature fluidized bed. To get a better understanding of the agglomeration mechanism, the (de-)fluidization behavior of micron-sized iron oxide particles in a 3-D fluidized bed is investigated using Computational Fluid Dynamics coupled with a coarse-grained Discrete Element Method (CFD-cgDEM). The inter-particle cohesive force is considered as a temperature-dependent solid bridge force. The coarse-grained method is first verified by comparing results for different scaling factors. Subsequently, the effects of temperature on the bed pressure drop, void fraction distribution, particle velocity distribution, and agglomerate size are investigated. In conclusion, the developed model shows the capacity for reliable prediction of particle agglomeration behavior, which can shed light on the design of the DRI process in high-temperature fluidized beds. • Modeling agglomeration behavior of micron-sized combusted iron particles. • A coarse-grained method is extended to model cohesive dense gas-solid flows. • The inter-particle cohesive force is considered as a temperature-dependent solid bridge force. • Effects of temperature and solid bridge strength on bed dynamics are studied. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon nanotube (CNT)-Fe x O y composites (CFs) are developed for lithium-ion batteries. • CNT-guided combustion waves offer scalable synthesis-optimization strategy for CFs. • CNTs provide path of thermochemical reaction and help disperse iron oxide particles. • CNTs form conductive network and prevent loose Fe x O y particles during pulverization. • Optimized CFs exhibit notably high cycle capacity, rate capability and cycle life. The design and synthesis of suitable transition metal oxide (TMO) with carbonaceous material are crucial to produce high-performance anodes for Lithium-ion batteries (LIBs). Here, we show a facile synthesis method for iron oxide and carbon nanotube (CNT) composite via CNT-guided combustion waves. The combustion waves propagate through a freestanding film composed of multi-walled CNTs (MWCNTs), iron nitrate, and combustible nitrocellulose, synthesizing the composite in one-pot within a few seconds. The resulting composite consists of MWCNT networks encapsulating iron oxide submicron particles (CFs). The composite electrode employing optimized CFs provides exceptional initial specific capacity and rate capability (792 mAh/g at 0.1C and 588 mAh/g at 5C) and an increased capacity of 1215 mAh/g after 500 charge–discharge cycles at 1C. The morphological and electrochemical characterization reveal pulverized nanoparticles encapsulated within MWCNT networks, entailing hybrid capacities of redox conversion and pseudocapacitance. This facile synthesis method for TMO–MWCNT composites provides a feasible family of low-cost composite electrodes for high-performance LIBs. [ABSTRACT FROM AUTHOR]

The structure and linear/nonlinear optical properties of iron oxide (Fe 2 O 3) nanoparticles (NPs) films are examined for environmentally friendly applications. Undoped and La, Mg and La/Mg co-doped Fe 2 O 3 NPs films were equipped using the spray pyrolysis procedure. The structural, morphological and optical properties of the films were characterized by X-ray diffractometer, FT-IR spectrophotometer, FE-SEM and UV–visible–NIR spectrophotometer. XRD analysis exposes that the samples possess a rhombohedral structure of α- Fe 2 O 3 (hematite). Besides, the crystallite size of the undoped Fe 2 O 3 NPs increases from 20.7 nm to 21.8 nm (La/Fe 2 O 3), 23.0 nm (Mg/Fe 2 O 3) and 24.4 nm (La + Mg/Fe 2 O 3). The direct/indirect optical band gap of the undoped Fe 2 O 3 film decreases from 2.47 eV/1.87 eV to 2.43 eV/1.72 eV (La/Fe 2 O 3), 2.37 eV/1.65 eV (Mg/Fe 2 O 3) and 2.31 eV/1.56 eV (La + Mg/Fe 2 O 3). Moreover, the effect of La/Mg co-doping on the refractive index, extinction coefficient, dielectric constants, linear optical susceptibility (χ(1)), third-order nonlinear susceptibility (χ(3)) and nonlinear refractive index (n 2) of Fe 2 O 3 NPs have been explored. In instance, the real dielectric constant of the undoped Fe 2 O 3 NPs decreases at 600 nm from 6.46 to 5.00 (La/Fe 2 O 3), 3.80 (Mg/Fe 2 O 3) and 3.17 (La + Mg/Fe 2 O 3). The ability to tailor the linear/nonlinear optical properties of Fe 2 O 3 NPs films upon La/Mg co-doping nominate them for uses in a lot of environmentally friendly applications. [Display omitted] • Undoped and La/Mg dual-doped iron oxide nanostructures were prepared by the spray pyrolysis procedure. • XRD analysis exposes that the undoped and doped nanostructures possess a rhombohedral hematite structure. • The direct/indirect energy band gap (E g) varies from 2.47 eV/1.87 eV (undoped Fe 2 O 3) to 2.31 eV/1.56 eV (La + Mg/Fe 2 O 3). • Nonlinear optical susceptibility of the doped and undoped Fe 2 O 3 NPs has been explored. • La/Mg co-doped Fe 2 O 3 NPs are nominated for applications in photocatalysts and eco-friendly devices. [ABSTRACT FROM AUTHOR]

• 176 thermal analyses of the hydrogen reduction of iron oxide powders reviewed. • Results highly sensitive to water presence and particle characteristics. • Kinetic models of varying complexity proposed, none supersede others. [Display omitted] The reduction of iron oxide with hydrogen is a much-studied research topic, whose interest is growing even more with the emergence of new applications, for example the hydrogen-based direct reduction or for the production of a carbon-free chemical energy carrier. But the numerous works on this topic reveal the great disparity in the authors' findings, especially regarding the reduction of powders. And while many authors point out this issue, no attempt has been made to converge towards a common understanding of this heterogeneous thermochemical conversion. The endeavor of the present review is to identify the points of consensus, and where discrepancies exist, to explain them. The first part starts with a revision of the latest recommendations on the thermodynamics of iron and its oxides, easing the further comprehension of the reduction process. Then, twelve publications meeting specific criteria on the sample type and reducing agents are systematically confronted. The types of experiments and major experimental conditions have been listed, leading to the identification of typical profiles. Furthermore, chemical pathways are proposed based on these observations and supported by various analytical measurements. Finally, the multiple mathematical approaches to derive kinetic models are compared and discussed. This present review points out the need for appropriate experimental conditions to derive the intrinsic chemistry of the reduction, such as the limitation of water vapor, and also emphasizes the need for more detailed chemical mechanisms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel catalytic system consisted of iron oxide magnetic nanoparticle and catechol. • Catechol-generated ROS further converted to hydroxyl radical by iron. • Initiates polymerization of wide ranges of monomers in an oxygenated solution. • Magnetic, bilayer hydrogels were formed with improved mechanical property. Phenol and its derivatives are the most used polymerization inhibitors for vinyl-based monomers. Here, we reported a novel catalytic system composed of mussel inspired adhesive moiety, catechol, in combination with iron oxide nanoparticles (IONPs) to generate hydroxyl radical (OH) at pH 7.4. Catechol-containing microgel (DHM) was prepared by copolymerizing dopamine methacrylamide (DMA) and N -hydroxyethyl acrylamide (HEAA), which generated superoxide (O 2 −) and hydrogen peroxide (H 2 O 2) as a result of catechol oxidation. In the presence of IONPs, the generated reactive oxygen species were further converted to OH, which initiated free radical polymerization of various water-soluble acrylate-based monomers including neutral (acrylamide, methyl acrylamide, etc.), anionic (2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt), cationic ([2-(methacryloyloxy)ethyl]trimethylammonium chloride), and zwitterionic (2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide) monomers. Compared with the typical free radical initiating systems, the reported system does not require the addition of extra initiators for polymerization. During the process of polymerization, a bilayer hydrogel was formed in situ and exhibited the ability to bend during the process of swelling. The incorporation of IONPs significantly enhanced magnetic property of the hydrogel and the combination of DHM and IONPs also improved the mechanical properties of these hydrogels. [ABSTRACT FROM AUTHOR]

Understanding water absorbency in paper is challenging as fibre swelling and out-of-plane deformation occur simultaneously during liquid imbibition. Liquid absorption is commonly accessed by gravimetric tests, which provides limited information on the local spatial and temporal distribution of fluid in the substrate. In this work, we developed iron tracers to map liquid imbibition in paper by in situ precipitation of iron oxide nanoparticles during passage of the wetting front. The iron oxide tracers were found to be robustly attached to the cellulosic fibres. After liquid absorption tests, absorbency was investigated by mapping the distribution of iron in 3D using X-ray micro-computed tomography (μCT) and in 2D using energy-dispersive X-ray spectroscopy. We demonstrate a difference in tracer distribution between the wetting front and the fully saturated region supporting that imbibition proceeds in two phases, i.e. liquid percolation through the cell wall initially prior to filling of the external pore spaces. Critically, we demonstrate that these iron tracers enhance image contrast and allow for new imaging modalities in μCT for fibre networks. [Display omitted] [ABSTRACT FROM AUTHOR]

Ammonia, a significant atmospheric pollutant, requires effective emission control due to its inherent toxicity and the generation of secondary pollutants like particulate matter. This control can be achieved through various methods, including catalytic processes. Therefore, our study focuses on evaluating the potential of catalysts based on iron oxide and nickel oxide supported on γ–Al 2 O 3 for the selective catalytic oxidation of NH 3 to N 2 (NH 3 -SCO). The γ–Al 2 O 3 was obtained by thermal decomposition of aluminum hydroxide, and 5 or 10 wt% of Fe or Ni was added through wetness incipient impregnation. XRD diffractograms confirmed the formation of the γ–Al 2 O 3 phase. XRD, H 2 -TPR, and UV–vis DRS data showed the presence of Fe 2 O 3 , NiO, and NiAl 2 O 4 in the catalysts. Introducing metal oxides onto the support led to a drop in the specific area, pore size, pore volume, and NH 3 desorption, which was higher for the catalysts containing Fe. The catalysts were active in NH 3 -SCO, and the insertion of Fe or Ni was essential because it promoted a significant increase in the NH 3 conversion (∼75 % Fe and ∼55 % Ni), compared to pure support (∼8 %), mainly from 400 °C. However, doubling the metal content has not resulted in a considerable increase in NH 3 conversion. The N 2 selectivity was higher for the catalysts containing Ni (∼85 %) from 400 °C compared to catalysts containing Fe (∼76 %). Such behavior was due to the larger surface area of the Ni-containing catalysts. Despite that, the 5Fe/γ–Al 2 O 3 catalyst emerged as the most effective option for NH 3 -SCO applications, combining higher NH 3 conversion and good N 2 selectivity. [Display omitted] • Thermal decomposition of Al(OH) 3 was effectively to obtain γ-Al 2 O 3 with mild and strong acid sites. • H 2 -TPR and UV–vis DRS data showed the formation of Fe 2 O 3 , or NiO in catalysts. • XRD showed NiAl 2 O 4 peaks in Ni/γ-Al 2 O 3. • The increasing in the metal content in catalysts did not considerably contribute in NH 3 conversion and N 2 selectivity. • At 500 °C, NH 3 conversion for 5Fe/γ-Al 2 O 3 reached 75 % and a selectivity of 80 % for N 2 formation. [ABSTRACT FROM AUTHOR]

A series of rare earth Keggin-type tungstophosphorate doped iron oxide catalysts were prepared by physical mixing method. The effects of type and the content of rare earth element over NH 3 -SCR activity were investigated and the catalysts were characterized by FT-IR, XRD, SEM, EDS, XPS, BET, TGA, ICP-AES, H 2 -TPR and NH 3 -TPD. It is indicated that the addition of rare earth Keggin-type tungstophosphorate could increase the NH 3 -SCR activity of the iron oxide catalysts, while the effect of rare earth species on SCR activity over Fe y O x is not obvious. Effects of O 2 concentration, SO 2 and SO 2  + H 2 O on NH 3 -SCR activity over NdPW/Fe y O x(25) and the control experiments were also investigated, the results of which illustrates that O 2 exerts a significant promotion effect on the SCR reaction and the impact of SO 2 (470 ppm) on catalytic activity is almost negligible. NdPW/Fe y O x(25) presents appealing properties of hydrothermal stability and SO 2 -tolerance, and exhibits a great potential in practical applications. [ABSTRACT FROM AUTHOR]

Toxicological evaluation of nanoparticles (NPs) requires the utilization of in vitro techniques due to their number and diverse properties. Cell culture systems are often lacking in their ability to perform comparative toxicity assessment due to dosimetry issues and capacity to simulate in vivo environments. Upon encountering a physiological environment, NPs become coated with biomolecules forming a biocorona (BC), influencing function, biodistribution, and toxicity. Disease-induced alterations in the biological milieu can alter BC formation. This study evaluates the role of low-density lipoprotein (LDL) in altering macrophage responses to iron oxide (Fe 3 O 4 ) NPs. BCs were formed by incubating Fe 3 O 4 NPs in serum-free media, or 10% fetal bovine serum with or without LDL present. Following exposures to a normalized dose (25 μg/mL), macrophage association of Fe 3 O 4 NPs with a LDL-BC was enhanced. TNF-α mRNA expression and protein levels were differentially induced due to BCs. Cell surface expression of SR-B1 was reduced following all Fe 3 O 4 NPs exposures, while only NPs with an LDL-BC enhanced mitochondrial membrane potential. These findings suggest that elevations in LDL may contribute to distinct BC formation thereby influencing NP-cellular interactions and response. Further, our study highlights challenges that may arise during the in vitro evaluation of disease-related variations in the NP-BC. [ABSTRACT FROM AUTHOR]

Iron oxide is a widely used sensitive material for gas sensor applications. They have fascinated much attention in the field of gas sensing and detecting under atmospheric conditions and at 200 °C temperature due to their low cost in production; simplicity and fast of their use; large number of detectable gases. Iron oxide gas sensors constitute investigated for hazardous gases used in various fields. The morphological structure (particle size, pore size, etc. ), optical, magnetic and electrical properties of Ni:Fe 2 O 3 , Mg:Fe 2 O 3 and Fe 2 O 3 thin films which grown by Spray pyrolysis (SP) have been investigated. XRD, Raman and AFM techniques have been used for structural analysis. AFM measurements have been provided very useful information about surface topography. I-V (Van der Pauw) technique has been used for response of gas sensor. These devices offer a wide variety of advantages over traditional analytical instruments such as low cost, short response time, easy manufacturing, and small size. [ABSTRACT FROM AUTHOR]

Bionanocomposites fabricated using metal nanoparticles serve a wide range of biomedical applications viz., site targeted drug delivery, imaging etc. Theranostics emerge as an important field of science, which focuses on the use of single entity for both disease diagnosis and treatment. The present work aimed at designing a multifunctional nanocomposite comprising of iron/gold hybrid nanoparticles, coated with oleyl chitosan and conjugated with methotrexate. The HR-TEM images revealed the spherical nature of the composite, while it's nontoxic and biocompatible property was proved by the MTT assay in NIH 3T3 cells and hemolysis assay. Though the VSM results exhibited the magnetic property, the MRI phantom images and X-ray contrast images demonstrated the potential of the composite to be used as contrast agent. Thus the prepared nanocomposite possess good cytocompatibility, magnetic property and also high X-ray attenuation, wherein it could serve as a novel platform for both MRI and CT diagnosis, as well as drug conjugation could aid in targeted drug delivery. [ABSTRACT FROM AUTHOR]

Ceria-modified iron oxide exhibits high redox performance superior to that of pure iron oxide, which can inhibit the deactivation caused by sintering of materials. In the present work, the ceria-modified iron oxide is investigated as an oxygen carrier for hydrogen production via chemical-looping water splitting process (CLWS). To identify the role of CeO 2 , the performance evolution and element migration of the mixed oxides during redox cycling were discussed in detail. Comparing the obvious deactivation of pure iron oxide sample, ceria-modified iron oxide shows relative constant production of hydrogen during the successive recycling water splitting. FeCe20 sample with a CeO 2 mole percent of 20% shows the highest average yield of hydrogen (8651 μmol/g) with a Fe average oxygen recovery rate of 67.7% among Fe-Ce mixed oxides with different Ce molar percentage (x = 0, 10, 20 and 40%). In spite of materials sintering, the oxygen releasing/acquiring capacity and reactivity of Fe-Ce mixed oxides are three times higher than that of pure iron oxide after redox treatment. This can be ascribed to the preferable dispersion of Ce-based sub-micro particles (CeO 2 and CeFeO 3 ) and enhanced Fe-Ce interactions generated from active sites at the contact interface between iron oxides (mainly Fe 3 O 4 particles) and Ce-based sub-micro particles (CeO 2 and CeFeO 3 ) after cycling. [ABSTRACT FROM AUTHOR]

Present article describes the development of novel electrode for the electrochemical detection of fluoride ion (F − ) present in water. The electrode is prepared by growing thin iron (III) oxide hydroxide film on conducting glass substrate through simple and cost effective dip coating technique. Electrochemical sensing performances of the developed electrode through cyclic voltammetric and amperometric technique are studied within a three electrode chamber. Ag/AgCl and Pt are used as reference and counter electrodes respectively to carry out the sensing experiments. The developed working electrode shows distinguishable cyclic voltammetric and amperometric response in presence of different concentration (0.27–2.48 mM) of aqueous fluoride solution. The interference of the sensor is verified in presence of nitrate (NO 3 − ) and chloride (Cl − ) ions. In order to understand the behaviour of electrochemical interaction, the phase and morphology of the electrode material is studied prior and after sensing. A plausible mechanism is proposed for the electrochemical sensing of fluoride by iron (III) oxide hydroxide film. [ABSTRACT FROM AUTHOR]

In general a nanocomposite material has better characteristics than each individual component, due to the effects produced by the synergies between the organic material and the nanoscale of the inorganic material. In this work new hybrid nanocomposites based on poly(3-hexylthiophene) (P3HT) and FeO(OH) nanoparticles were synthesized and characterized. FeO(OH) nanoparticles were synthesized by chemical bath. The P3HT-FeO(OH) nanocomposites were in-situ synthesized by chemical oxidation of 3HT (Sugimoto method) at different weight ratios (3HT/FeO(OH): 1/0.029, 1/0.048 and 1/0.074), using FeCl 3 as oxidant/catalyst. Effect of FeO(OH) nanoparticles content in P3HT on its physicochemical properties was studied. The dyads and triads configuration was determined by 1 H NMR. In comparison with P3HT, a higher regioregularity was obtained in the composites with 3HT/FeO(OH) weight ratio of 1/0.048 and 1/0.074. The FTIR analyzes showed the presence of FeO(OH) in the P3HT and a strong interaction between P3HT and FeO(OH). Thermal stability and decomposition temperature were determined by thermogravimetry (TGA), better thermal stability and higher degradation temperature were showed by the composites. The UV–Vis and photoluminescence analyzes showed higher absorbance and higher photoluminescence intensity in P3HT-FeO(OH) nanocomposites, indicating the incorporation of FeO(OH) in the P3HT. Finally the composites were characterized by SEM and X-ray analysis. Composites showed interesting properties for optoelectronic applications. [ABSTRACT FROM AUTHOR]

We have successfully introduced sugar alcohol (mannitol) onto the surface of iron oxide magnetic nanoparticles and investigated its role on their colloidal stabilization. The mannitol functionalized magnetic nanoparticles (MMNPs) were prepared through co-precipitation of Fe +2 and Fe 3+ ions in basic medium under N 2 atmosphere followed by in-situ coating of D-mannitol. The formation of iron oxide nanoparticles is evident from XRD and TEM analysis. The coating of nanoparticles with mannitol is analyzed by FTIR, TGA, DLS and zeta-potential measurements. It has been observed that the presence of mannitol on the surface of nanoparticles strongly affect their surface potential and colloidal stability. They show room temperature superparamagnetism with optimal magnetization of 60.5 emu/g at 20 kOe and protein resistant behaviour in physiological medium. These MMNPs were employed as drug delivery carrier using anticancer drug, doxorubicin hydrochloride (DOX). The drug molecules were loaded onto the surface of nanoparticles through electrostatic interactions between positively charged DOX and negatively charged MMNPs. A loading efficiency of 60% has been observed at DOX to MMNPs ratio (w/w) of 1:10 and the loaded drug showed pH dependent sustained release characteristics. Further, MMNPs exhibited good self-heating ability under applied AC magnetic field, thus they can be used as efficient heating source for hyperthermia therapy. [ABSTRACT FROM AUTHOR]

Iron salts are routinely dosed in wastewater treatment as a means of achieving effluent phosphorous concentration goals. The iron oxides that result from addition of iron salts partake in various reactions, including reductive dissolution and phosphate adsorption. The reactivity of these oxides is controlled by the conditions of formation and the processes, such as aggregation, that lead to a reduction in accessible surface sites following formation. The presence of organic compounds is expected to significantly impact these processes in a number of ways. In this study, amorphous ferric oxide (AFO) reactivity and aging was investigated following the addition of ferric iron (Fe(III)) to three solution systems: two synthetic buffered systems, either containing no organic or containing alginate, and a supernatant system containing soluble microbial products (SMPs) sourced from a membrane bioreactor (MBR). Reactivity of the Fe(III) phases in these systems at various times (1–60 min) following Fe(III) addition was quantified by determining the rate constants for ascorbate-mediated reductive dissolution over short (5 min) and long (60 min) dissolution periods and for a range (0.5–10 mM) of ascorbate concentrations. AFO particle size was monitored using dynamic light scattering during the aging and dissolution periods. In the presence of alginate, AFO particles appeared to be stabilized against aggregation. However, aging in the alginate system was remarkably similar to the inorganic system where aging is associated with aggregation. An aging mechanism involving restructuring within the alginate-AFO assemblage was proposed. In the presence of SMPs, a greater diversity of Fe(III) phases was evident with both a small labile pool of organically complexed Fe(III) and a polydisperse population of stabilized AFO particles present. The prevalence of low molecular weight organic molecules facilitated stabilization of the Fe(III) oxyhydroxides formed but subsequent aging observed in the alginate system did not occur. The reactivity of the Fe(III) in the supernatant system was maintained with little loss in reactivity over at least 24 h. The capacity of SMPs to maintain high reactivity of AFO has important implications in a reactor where Fe(III) phases encounter alternating redox conditions due to sludge recirculation, creating a cycle of reductive dissolution, oxidation and precipitation. [ABSTRACT FROM AUTHOR]

In an era dominated by electronic equipment, the development of high-efficiency electromagnetic wave (EMW) absorbers is of great significance in solving the problem of electromagnetic (EM) pollution. Heterointerface engineering for optimizing EMW absorption performance depends on the design of vacancy, defect, and heterogeneous interface, which remains a considerable challenge in adjusting the micro and macro-interface effects. In this work, S atoms are incorporated into a dielectric-magnetic complementary system (Fe 3 O 4 /Fe 7 S 8 @C) to arouse the polarization effect of vacancies, defects, and non-uniform interfaces, thus tremendously boosting the EM energy attenuation capacity. Besides, the carbon shell provides more propagation paths for the dissipation of EMWs, and dielectric-magnetic synergy improves impedance matching. Eventually, in comparison with Fe 2 O 3 and Fe 3 O 4 @C composites, interface-engineered Fe 3 O 4 /Fe 7 S 8 @C acquires a much better EM wave absorption performance. Its minimum reflection loss value reaches as much as −56.2 dB with a thickness of only 1.6 mm, and the corresponding effective absorption bandwidth (EAB) is up to 4.5 GHz. This unique hydrangea-like layered structure provides space to facilitate non-uniform coupling between the layers and has strong anisotropy to enhance the magnetic response. The high density of magnetic flux in the nanosheets builds a three-dimensional magnetic coupling network, which is supported by off-axis electron holography. Besides, the radar cross section from HFSS simulation further confirms that S -doping can favor the best synergy between dielectric and magnetic losses, facilitating the composite to achieve a more optimal impedance matching and improve the absorption capacity. In conclusion, this work presents new ideas for the design of excellent absorbing materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Activated carbon AC was treated with Kmn04 and the treated AC was used to be impregnated with iron oxide. The ratio of 0.1 M KMnO 4 treatment on AC to the 0.1 M iron sulfate precursor (0.1KMnO 4 :0.1Fe) showed the most efficient adsorbent with an adsorption capacity of 108.60 mg/g. The CO 2 adsorption isotherm at 25 °C was assessed with the adsorption isotherm model found that the Freundlich model to be the best fit which implies the multilayer adsorption onto heterogeneity surface. The adsorbent was used to perform CO 2 adsorption at 30, 40, 50 and 70 °C in which the optimum adsorption temperature was at 30 °C. The decrease in adsorption capacity with increasing temperature indicates that a physisorption process takes place. The kinetic data for CO 2 adsorption at different temperatures were well fitted to the pseudo-second-order kinetic. The adsorption was near to the chemisorption process based on the activation energy of 39.8 kJ/mol. It might be due to the weak interaction between CO 2 and AC and strong bonding between CO 2 and iron oxide. The adsorption capacity insignificantly reduced by 3.5% after four cycles showed practically efficient in CO 2 capture. [Display omitted] • A sorbent was synthesized by a ratio of KMnO 4 treated on AC towards iron oxide loading. • The most efficient adsorbent for CO 2 capture was 0.1KMnO 4 :0.1 Fe. • Freundlich model showed the best fit to the CO 2 adsorption isotherm at 25 °C. • The pseudo-second-order kinetic fit better with activation energy of 39.8 kJ/mol. [ABSTRACT FROM AUTHOR]

One of the most pressing problems in rural areas is drinking water that has been contaminated with arsenic and other organic and inorganic pollutants. A significant risk of arsenic toxicity remains for many rural populations due to inadequate public awareness campaigns regarding the health impacts of consuming arsenic-contaminated water. As a result, inexpensive techniques are essential to eliminate arsenic from water. The feasibility of iron oxide coated biosand filtration for eliminating As5+ from aqueous solutions was examined in this study through batch and semi-continuous tests. An iron oxide coated biosand filter showed the best arsenate removal efficiency, with up to 99.8% removal over 120 days. The adsorption rate tended to increase with the adsorbent dosage. Experiments at different iron oxide dosages confirmed that the adsorption of arsenate onto iron oxide particles followed a pseudo second-order model. Langmuir and Freundlich models were used to describe the adsorption capacity, and both models showed a good fit (R2 >0.90) to the adsorption of arsenate at different levels of water hardness. After filtration, a leachability test was performed on the spent iron and sand particles. The results indicated that the leachate contained low arsenate concentrations, and should be carefully treated as hazardous waste. [Display omitted] • Efficiencyof the biosand filter is increased by the addition of a layer of sand coated in iron oxide. • Iron coated biosand efficiently removed As5+ from synthetic ground water. • Langmuir and Freundlich models showed a good fit to the adsorption of As5+. • Adsorption rate tended to increase with the adsorbent dosage. • Iron coated biosand demonstrated an As5+ removal efficiency of 99.8% over 120 days. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel magnetic LLP@Fe 3 O 4 composite was successfully synthesized and characterized. • LLP@Fe 3 O 4 composite possessed a high surface area and good magnetic separation. • The adsorption capacity for MO was 282.3 mg/g by LLP@Fe 3 O 4 at 298 K. • Electrostatic interaction played an important role in the adsorption mechanism. • The removal rate of MO still reached 78.4% after five cycle regenerations. The goal of this work was to prepare a novel magnetic nanocomposite of Lotus leaf powder@iron oxide (LLP@Fe 3 O 4) to remove Methyl Orange (MO) from a liquid medium. The co-precipitation approach was used to successfully synthesize the LLP@Fe 3 O 4 composite, which was then characterized using FT-IR, XRD, pH PZC , SQUID-VSM, BJH/BET, and FE-SEM/EDX analysis. Batch tests were carried out to investigate the adsorption behaviour and mechanisms. The optimal MO removal efficiency of LLP@Fe 3 O 4 reached up to 94.3% under the optimum reaction conditions (LLP@Fe 3 O 4 dosage = 50 mg/30 mL, stirring speed = 200 rpm, contact period = 120 min, MO initial concentration = 20.8 mg/L, temperature = 298 K, and pH = 5.1). Adsorption isotherms and kinetics were analyzed using Temkin, Freundlich, Langmuir, Dubinin-Radushkevich (D-R), pseudo-second-order (PSO), intra-particle diffusion (IPD), pseudo-first-order (PFO), and Elovich models. Adsorption of MO on LLP@Fe 3 O 4 is best matched to the Langmuir isotherm and PSO kinetic models. The data was analyzed utilizing four errors (SSE, ARE, RMSE, and χ2) and regression coefficient functions to estimate the best-fitting kinetic and isotherm models. The maximal monolayer adsorption uptake of MO was estimated to be 282.3 mg/g at 298 K. The thermodynamic variables, namely entropy (Δ So = -98 J/mol K), enthalpy (Δ Ho = -35.6 kJ/mol), and Gibbs free energy (Δ Go = -6.2808 kJ/mol at 298 K), indicated that the adsorption of MO onto LLP@Fe 3 O 4 was spontaneous, exothermic, and feasible. The LLP@Fe 3 O 4 composite may be regenerated and readily separated from the liquid medium without losing any weight. After regeneration, the LLP@Fe 3 O 4 still has good adsorption efficiency for up to five cycles of adsorption and desorption. The experimental findings of this study output could be confirmed that LLP@Fe 3 O 4 is a potential adsorbent to remove dyestuff from wastewater. [ABSTRACT FROM AUTHOR]

Pesticide residues create an ecological ecosystem that is incredibly dangerous and presents major risks to human health. To solve this issue, scientists are concentrating on creating extremely effective composites with superior photocatalytic performance. Even if several efforts have been made to remove pesticides and dangerous compounds using adsorption, the development of novel adsorbents with large adsorption capabilities is still very desirable. Here, the photocatalytic of carbamate pesticides in aqueous solution under simulated sunlight irradiation in the existence of Fe 3 O 4 , CuO/Cu 2 O, MIL-125-NH 2 , Fe 3 O 4 @MIL-125-NH 2 and CuO/Cu 2 O@MIL-125-NH 2 were investigated. The photocatalytic process may be credited with the effective electron-hole separation and wider area of light response. Moreover, the mechanism of pesticide photocatalytic process was discovered as mineralization of pesticides to carbon dioxide, water, sulphate, and ammonia. Total organic carbon (TOC) analysis was used to quantify the mineralization of pesticides while UV spectroscopy was used to measure the rates of pesticides photocatalytic activity. CuO/Cu 2 O@MIL-125-NH 2 and Fe 3 O 4 @MIL-125-NH 2 composite demonstrated the maximum pesticide photocatalytic efficiency and outstanding cycle stability. The antimicrobial potency was increased and the inhibition zone was minimised when treated by a parent MIL-125-NH 2 and its composites, which is surprising data when employing CuO/Cu 2 O@MIL-125-NH 2 and Fe 3 O 4 @MIL-125-NH 2 nanocomposite as an anti-bacterial material. [Display omitted] • Fe 3 O 4 and CuO/Cu 2 O were attached to MIL-125-NH 2 using self assembly protocol. • First example of the Fe 3 O 4 /MIL-125-NH 2 and CuO/Cu 2 O/MIL-125-NH 2 composite for pesticide degradation was applied. • Unique adsorption/photolysis mechanism of Fe 3 O 4 and CuO/Cu 2 O incorporated onto MIL-125-NH 2 was proposed. • Enhancing the photocatalytic activity performance on photolysis of pesticide was observed. • Fantastic antimicrobial activity was appeared for the prepared photocatalysts. [ABSTRACT FROM AUTHOR]

The present study shows that TiC x O y ceramics and TiC x O y -Fe cermets could be fabricated from nanocrystalline powders of TiC and TiC-Fe 2 O 3. The ball-milled TiC contains a high amount of oxygen impurities, which are accommodated by the oxycarbide phase. Upon heating, oxycarbide partially decomposes via evolution of CO and promotes the reduction of Fe 2 O 3 to a mix of Fe 3 O 4 /Fe starting from 400 °C. In the 550–700 °C range, Fe 3 O 4 is converted to plain iron by oxidation of TiC, which increases the oxygen content in TiC x O y and leads to segregation of Ti 4 O 7. At higher temperatures, oxide and oxycarbide phases of titanium continue to release CO, while Fe-based alloys melt at about 1400–1450 °C and facilitate densification. Depending on the starting content of Fe 2 O 3 , sintered samples demonstrate 0–24 vol% of metallic binder, 0.8–1.4 μm grains, hardness of 7–18 GPa and toughness of 4–8 MPa·m1/2. [Display omitted] • Nanocrystalline TiC contains oxygen impurities accommodated by TiC x O y oxycarbide. • Oxycarbide releases CO during heating and promotes reduction of Fe 2 O 3 to Fe 3 O 4. • Fe 3 O 4 converts to Fe via oxidation of TiC which increases oxygen content in oxycarbide. • Sintering of milled TiC and TiC-Fe 2 O 3 provides TiC x O y ceramics and TiC x O y -Fe cermets. [ABSTRACT FROM AUTHOR]

Magnetic calcium (Ca) and magnesium (Mg)-modified iron oxide adsorbents were synthesized using CaCl 2 , CaCO 3 , MgCl 2 , or MgCO 3 by a simple combustion method for the remediation of phosphate. Modification with Ca and Mg significantly improved the phosphate adsorption capacity of the magnetic iron oxide adsorbents. Additionally, polyvinyl alcohol (PVA) was incorporated during synthesis to aid in the magnetism of the samples, making the adsorbents easy to separate from solutions. Physicochemical properties of the adsorbents were determined by characterization with X-ray diffraction (XRD), particle analyzer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution TEM (HR-TEM). Batch adsorption experiments were carried out to gain insight on the materials' ability to remove phosphate from water supplies. Samples without the addition of PVA had higher phosphate capacities (ranging from 16.92 to 16.97 mg g −1 ) compared to PVA-containing samples (ranging from 12.39 to 16.74 mg g −1 ), yet the PVA-containing samples were magnetic and thus, easily separable. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations have been carried out to investigate the tribological, structural and rheological properties of thin film hexadecane confined between different iron and iron oxide surfaces. The interfacial slip becomes severe with the increase of loading pressure and shear rate but it is insensitive to temperature. The shear stress increases with the loading pressure whereas the coefficient of friction shows a contrasting propensity. The shear stress and coefficient of friction increase with shear rate; and decrease with higher surface temperature. A logarithmic function has been proposed to correlate the variation of friction with shear rate. The shear viscosity increases exponentially with the loading pressure but this rheological component levels off when the loading pressure exceeds a critical value. [ABSTRACT FROM AUTHOR]

High purity hydrogen has been obtained by “ steam-iron ” process from lighter fractions of synthetic bio-oils of different compositions in a single fixed bed reactor operating cyclically. This process in closely related to chemical looping producing and purifying hydrogen in a single reactor. The feedstock consisted of a blend of four model compounds representing the lighter fractions of a bio-oil. Acetic acid has been chosen as representative of the acidic fraction, hydroxyacetone of the ketonic/aldehydic, methanol of the alcoholic and finally water of the aqueous one. Content of each model compound in the mixture has been fixed by design of experiments techniques according to composition of real bio-oils found in literature. First step involves the reduction of an iron oxide at several temperatures (650–850 °C) by the action of a synthetic bio-oil, which catalytically decomposes into gaseous reductive species (mainly hydrogen and carbon monoxide). Solid carbon was also produced and deposited on the surface of the solid. Once the iron oxide is completely reduced, a second step consists in the oxidation of the metallic iron with steam releasing pure hydrogen. Along this reaction, and due to the low oxidation temperature (550 °C), carbon deposited in the previous step was not appreciably gasified, letting the released hydrogen be virtually free of carbon monoxide ([CO] < 20 ppm). Low proportions of water in the reductive gases have proved to exert a positive effect in the process, diminishing the residual carbon deposited on the solid bed, although decreasing reduction rates. The solid tested along this study, based on an iron oxide with small amounts of alumina and ceria, can produce pure hydrogen following a cyclic process, but exhibits a progressive loss of redox capacity of ca. 3 wt% after each cycle. [ABSTRACT FROM AUTHOR]

Targeting delivery of drugs in a specific manner represents a potential powerful technology in gliomas. Herein, we prepared a multifunctional targeted delivery system based on graphene oxide (GO) that contains a molecular bio-targeting ligand and superparamagnetic iron oxide nanoparticles on the surface of GO for magnetic targeting. Superparamagnetic Fe 3 O 4 nanoparticles was loaded on the surface of GO via chemical precipitation method to form GO@Fe 3 O 4 nanocomposites. Lactoferrin (Lf), an iron-transporting serum glycoprotein that binds to receptors overexpressed at the surface of glioma cells and vascular endothelial cell of the blood brain barrier, was chosen as the targeted ligand to construct the targeted delivery system Lf@GO@Fe 3 O 4 through EDC/NHS chemistry. With the confirmation of TEM, DLS and VSM, the resulting Lf@GO@Fe 3 O 4 had a size distribution of 200–1000 nm and exhibited a superparamagnetic behavior. The nano delivery system had a high loading capacity and exhibited a pH-dependent release behavior. Compared with free DOX and DOX@GO@Fe 3 O 4 , Lf@GO@Fe 3 O 4 @DOX displayed greater intracellular delivery efficiency and stronger cytotoxicity against C6 glioma cells. The results demonstrated the potential utility of Lf conjugated GO@Fe 3 O 4 nanocomposites for therapeutic application in the treatment of gliomas. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the removal of hydrogen sulfide (H 2 S) present in air using cellular concrete waste as the packing material. Air filtration was performed under biotic and abiotic conditions. Experiments were carried out in a laboratory-scale PVC column (internal diameter of 300 mm) filled with a volume of 70 L of cellular concrete (1 m height). The polluted air flow was generated at 4 m 3 h −1 corresponding to an Empty Bed Residence Time (EBRT) of 63 s. In dry conditions without biomass (abiotic conditions), cellular concrete can be an effective medium for the treatment of H 2 S in air. For an H 2 S concentration of 100 ppmv, the removal efficiency was around 70 % (Elimination Capacity (EC) of 5.6 g m −3 h −1 ). This finding can be explained by the physicochemical reactions that can take place between H 2 S and the cellular concrete components (mainly CaO, CaCO 3 and Fe 2 O 3 ). However, interactions between cellular concrete and H 2 S are not yet fully understood. Used as a packing material for H 2 S biofiltration (biotic conditions), cellular concrete waste efficiently treated (Removal Efficiency = 100 %) high concentrations of H 2 S (up to 133 ppmv corresponding to an EC of up to 10.5 g m −3 h −1 ). Physicochemical and biological mechanisms explaining H 2 S removal seem to occur simultaneously in the biofilter. At an EBRT of 63 s, the maximal elimination capacity (EC max ) was 17.8 g m −3 h −1 . A packed bed of cellular concrete also presents a satisfactory mechanical behavior with low pressure drops. [ABSTRACT FROM AUTHOR]

Mineral forms of iron oxide, such as hematite, goethite and jarosite, are important because they are widely distributed at the Earth’s surface and because they are used as indicators for mineral exploration. Iron oxide abundance in rocks containing these minerals can be estimated from the absorption depth at wavelengths of around 900 nm in a reflectance spectrum, but this depth is also affected by extraneous factors such as grain size and topography. This paper investigated the effect of grain size on reflectance spectra and proposed a method for estimating iron oxide abundance in surface rocks by using remotely sensed data with suppression of the effects of grain size and topography. Reflectance spectra were measured in a laboratory from rock powder samples of different grain sizes containing iron oxide minerals. While the reflectance increased with decreasing grain size, the presence of ferric iron caused the absorption depth to be almost constant at around 900 nm, irrespective of the chemical composition of the sample. In addition, the difference between the reflectance at 550 nm and 760 nm (Slope) was a function of grain size. Iron oxide abundance can be estimated accurately by MCR-900D, which is the maximum absorption depth at the absorption center after the effect of grain size and topography was suppressed by Slope and the continuum-removal method, which takes the ratio between the original spectrum and its continuum, respectively. Correlation of MCR-900D results with datasets of actual spectral and chemical iron oxide laboratory measurements revealed that the mineral forms also need to be considered. MCR-900D results were significantly correlated with rock samples classified as containing different forms of iron oxide minerals (hematite, goethite and jarosite). Finally, MCR-900D was applied to an AVIRIS dataset for the Cuprite site in Nevada, USA. The results represented the enrichment zones of iron oxide within hydrothermally altered areas. [ABSTRACT FROM AUTHOR]

Abundant endeavors have been undertaken to explore high-quality and inexpensive materials for capacitive deionization desalination. However, one major problem is the sluggish adsorption rate and inferior adsorption performance of these materials in practical applications. Herein, nitrogen-doped carbon nanofiber-reinforced hierarchical hollow iron oxide nanorods grown on electrospinning carbon nanofibers (denoted Fe 2 O 3 @CNFs) were rationally designed and synthesized for high-efficiency capacitive deionization. Such composition and distinctive hierarchical porous structure prevent agglomeration of Fe 2 O 3 nanorods, boosting the ionic/electronic transport through the synergistic effect between the Fe 2 O 3 nanorods and N-doped carbon nanofibers. When employed as a cathode for capacitive deionization without adding any polymeric binder or conductive additives, this material exhibits a high adsorption capacity of 114.97 mg/g and a rapid salt adsorption rate (7.79 mg/g min). Moreover, the sodium storage mechanism was revealed through ex situ XRD, EDX mapping and ex situ XPS. Density functional theory (DFT) calculations reveal that the electrons are redistributed at the heterojunction interface, refining the electrochemical activity. This work is anticipated to afford an innovative path for the development of porous transition metal oxide-based fibers with outstanding effectiveness and stability toward environmental research of high-performance capacitive deionization. [Display omitted] • A free-standing hierarchical hollow Fe 2 O 3 @CNFs hybrid electrode was fabricated. • A high electrosorption capacity and a rapid salt adsorption rate were achieved. • The hollow structure alleviates volume expansion and facilitates ion diffusion. • The faradic reaction and electroadsorption coupling removal mechanism was proven. • DFT were implemented to provide in-depth insights into the storage mechanism. [ABSTRACT FROM AUTHOR]

• An innovative galvanic cell simulated electrochemical reactions in pipe scale. • Electrochemical evidence verified the reduction of iron oxides in anoxic conditions. • Kinetics plays most important role in the reduction of iron oxide scale. • Goethite was transformed into magnetite as a result of the reduction of pipe scale. Iron release from pipe scale is an important reason for water quality deterioration in drinking water distribution systems (DWDS) globally. Disruption of pipe scale, release and transformation of iron compounds are hot topics in the field of water supply. The aim of this study is to determine whether and how ferric components in pipe scale be reduced under anoxic condition. In this study, new investigation approaches were applied, which include simplifying the complex scale into electrode pairs, developing novel simulating reactors and conducting tailored electrochemical assays. A galvanic cell reactor with anode of metallic iron (Fe0) and various cathode made of certain iron oxide (FeO x) was firstly developed to simulate the complex niche and components of pipe scale. Electrochemical methods were used to study the reduction characteristics of scale. The results proved that reduction of iron oxide scale did occur under anoxic condition. Electromotive forces between various electrodes match the Nernst Equation quite well. As main components in pipe scale, lepidocrocite (γ-FeOOH) was found to be the most reducible iron oxide but at low rate, while goethite (α-FeOOH) has weak reducibility but can be quickly reduced. As a result of electrochemical reactions, goethite in pipe scale was transformed into magnetite (Fe 3 O 4). By these means, electrochemical reaction mechanisms of pipe scale disruption were revealed, which is helpful to restrain pipe corrosion and water deterioration in DWDS. [Display omitted] [ABSTRACT FROM AUTHOR]

Hematite (α-Fe 2 O 3 , bandgap ~2.1 eV) is a potential photoanode candidate for photoelectrochemical water splitting. In this work, we report the preparation of Fe 2 O 3 with Ti4+ doping by hydrothermal treatment at 393 K and then annealing in the air at 873 K, with a second round of annealing in argon at 473 K. The two-step annealing process increased the photoelectrochemical performance of Ti-doped Fe 2 O 3 on a fluorine-doped tin oxide (FTO)-coated glass substrate (FTO/Ti-Fe 2 O 3) for water oxidation in 0.1 mol L−1 NaOH solution. Ti4+ doping was sourced from TiCl 4 in ethanol solutions of various concentrations. An energy-dispersive X-ray spectrometer (EDS) analysis confirmed that the optimized Ti/Fe atomic ratio in the solution was ~3%, which showed the highest photocurrent densities in the linear sweep voltammetry and chronoamperometry measurements. The two-step annealed FTO/Ti-Fe 2 O 3 generated a photocurrent density of 0.55 mA cm−2 at 1.50 V vs. reversible hydrogen electrode (RHE) under simulated one-sun illumination, which was approximately 3 times higher than that of the photoanodes annealed in air. Four-point probe resistivity measurements revealed that the two-step annealing resulted in a higher electrical conductivity than that of the samples annealed in air. The conductivity improvements induced by additional argon annealing at 473 K were ascribed to the increased donor density, which was confirmed by Mott–Schottky analysis and diffuse reflectance UV–visible–near-infrared spectra. We found that the strategy of Ti4+ doping and two-step annealing helped fabricate Fe 2 O 3 -based photoanode materials with better photocurrent density attributed to high electrical conductivity successfully. [Display omitted] • Fe 2 O 3 photoanode with Ti4+ doping was prepared for water oxidation. • Ti-doped Fe 2 O 3 was annealed in air at 873 K and in argon at 473 K. • The two-step annealing process increased the photoelectrochemical activity. • Electrical conductivity was improved with an increased donor density. • Ti4+ doping and two-step annealing provide a better photocurrent response. [ABSTRACT FROM AUTHOR]

Molybdenum (Mo) is a naturally-occurring trace element in drinking water. Most commonly, molybdate anions (MoO 4 2-) are in well water and breast milk. In addition, it is used in medical image testing. Recently, the EPA classified Mo as a potential contaminant, as exposure can lead to health effects such as gout, hyperuricemia, and even lung cancer. We have assessed the sorptive removal of aqueous molybdate using Douglas fir biochar (DFBC) and a hybrid DFBC/Fe 3 O 4 composite containing chemically-coprecipitated iron oxide (Fe 3 O 4). Adsorption was studied at various: pH values, equilibrium times (5 min-24 h), initial Mo concentrations (2.5–1000 mg/L), and temperatures (5, 25, and 40 °C) using batch sorption and fixed-bed column equilibrium methods. Langmuir capacities for DFBC and DFBC/Fe 3 O 4 (at pH 3, 2 hrs equilibrium) were within 459.3–487.9 mg/g and 288–572 mg/g, respectively. These adsorbents and their Mo-laden counterparts were characterized by elemental analysis, BET, PZC, SEM, TEM, EDS, XRD, and XPS. MoO 4 2- adsorption on DFBC is thought to be governed primarily via electrostatic attraction. Adsorption by DFBC/Fe 3 O 4 is primarily governed by chemisorption onto magnetite surface hydroxyl groups, while electrostatics prevail in the DFBC-exposed phase. Stoichiometric precipitation of iron molybdates triggered by iron dissolution was also considered. The data suggest that DFBC and DFBC/Fe 3 O 4 are promising candidates for molybdate sorption. [Display omitted] • Douglas fir biochar and its iron oxide analogue removed ∼500 mg/g aqueous molybdate. • Adsorption from anion mixtures and complex natural water was robust. • Fixed-bed column capacity for iron oxide/biochar was ∼19 mg/g. • Uptake was governed by chemisorption, hydrogen bonding and preciptiation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis, characterization and biosensing application of polypyrrole enwrapped nanoparticles. • The redox active sites of Fe 2 O 3 created passage for electron transportation. • La 2 O 3 induced massive defects for DA adsorption. • PPy provided stability and enhanced electron shuttling. • These synergistic properties amplified the transduction signals leading to the higher electrocatalytic activity for DA oxidation. Dopamine (DA) disorder has been associated in pathogenesis of many neuronal dysfunction. So, DA homeostasis is the thumbprint of enduring neuronal health and physiological condition. However, the development of molecular probes that allow in vitro screening of DA with spatiotemporal resolution is a great challenge. For this purpose, we report a synthesis, characterization and application of lanthanum oxide modified iron oxide nanoparticles enwrapped polypyrrole interface (La 2 O 3 @Fe 2 O 3 /PPy). This newly integrated material has been characterized via Raman spectroscopy, Scanning electron microscopy (SEM), Zeta Potential, X-ray diffraction spectroscopy (XRD) and Atomic force microscopy (AFM). The Fe 2 O 3 created passage for electron transportation owing to presence of redox active sites, La 2 O 3 introduction induced massive defects for analyte adsorption and PPy provided stability with enhanced electron shuttling. These synergistic properties eventually amplified the transduction signals leading to the higher electrocatalytic activity for DA oxidation. The designed La 2 O 3 @Fe 2 O 3 /PPy transducing interface accomplished selective DA sensing and a detection limit was found to be 1.2 nM in the linear bounds of 100 µM to 3.5 mM. In addition, the interface was effectively utilized to detect dopamine from the lacrimal fluid with decent recoveries. We antedate that this design will pave the ways for the in vitro analysis of DA from real samples with desired selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoO 3 -Fe 2 O 3 NC was synthesized by facile hydrothermal method. • MoO 3 -Fe 2 O 3 NC delivers the specific capacitance of 908F/g at 10 mV/s. • The MoO 3 -Fe 2 O 3 //AC asymmetric supercapacitor device exhibits the energy density of 43.3 Wh/kg and the power density of 600 W/kg. • The MoO 3 -Fe 2 O 3 //AC device delivered the cyclic stability of 81.17% after 2000 charge–discharge cycles. Two dimensional (2D) materials with excellent electrochemical property have been extensively studied to fabricate the high-performance supercapacitor electrodes for future energy storage applications. In this present work, 2D MoO 3 nanoplates were fabricated and their electrochemical performances were enhanced by the introduction of Fe 2 O 3 NPs in its lattice. As a result, the MoO 3 -Fe 2 O 3 NC demonstrates the high specific capacitance of. 908 F/g at 10 mV/s based on the cyclic voltammetry (CV) analysis. Moreover, the electrochemical impedance spectra (EIS) show the solution resistance (Rs) and charge transfer resistance (Rct) of 0.48 Ω and 0.01 Ω respectively. The MoO 3 -Fe 2 O 3 NC possesses long charge–discharge and high rate capabilities were revealed by Galvanostatic charge–discharge (GCD) analysis. The cyclic stability of MoO 3 -Fe 2 O 3 NC provides outstanding capacitive retention of 88.8% even after 3000 cycles. The asymmetric supercapacitor (ASC) device based on MoO 3 -Fe 2 O 3 //AC delivered a high energy density of 43.3 Wh/kg and power density of 600 W/kg. Furthermore, the ASC maintains a cyclic stability of 81.17 % after 2000 consecutive charge–discharge cycles. [ABSTRACT FROM AUTHOR]

ortho -Nitroaniline (o -NA) compounds are deemed to be a strongly toxic pollutant in nature and potentially carcinogenic; however, they are frequently utilized to synthesize dyes, pesticides, medicines, fungicides, pigments, and other organic chemicals. Their detection in an aqueous medium is fundamentally required to avoid the potential hazardous being created by these compounds. In this study, a novel sensor based on an Iron oxide (Fe 3 O 4) containing highly dispersed nitrogen-doped carbon quantum dots (N -CQDs@Fe 3 O 4 NFs) was demonstrated for the electrochemical detection of o -NA using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. N -CQDs@Fe 3 O 4 NFs were synthesized by hydrothermal method and studied by various analytical and spectroscopy techniques, which collectively reveal that the as-prepared composite has superior physical and chemical properties. The DPV study indicated that the o -NA sensor had a good limit of detection, linear range, and sensitivity in the range of 1.2 nm, 0.03–386.84 μ M, and 36.5575 μ A μM−1 cm−2, respectively, along with the sensor showed superior sensitivity when compared to the previously reported modified electrodes. Further, N -CQD/Fe 3 O 4 NFs worked as heterogeneous catalysts for the photocatalytic reduction of o -NA to o -phenylenediamine (o -PD) in an aqueous medium. The reaction was examined under UV–Visible spectroscopy, and the complete photocatalytic reduction was observed for the N -CQD/Fe 3 O 4 NFs in about 6 min with 96% as compared to other control samples; thus, authenticating the superiority of the synthesized composite in rendering the real-time applications. [Display omitted] • N -CQDs@Fe 3 O 4 NFs catalyst was prepared by hydrothermal method to detect the environmentally hazardous organic pollutant. • The o -NA sensor showed an excellent limit of detection of about 1.2 nM. • In addition, the N -CQDs@Fe 3 O 4 NFs catalyst is used for the photo-catalytic reduction of o -NA to OPD. • The electrocatalytic and photocatalytic studies are performed by CV, DPV, and UV–Visible spectroscopy. [ABSTRACT FROM AUTHOR]