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Copper-promoted iron oxides are commonly utilized in high-temperature water-gas shift (WGS) reactions. Although the promotional effect of Cu has been previously documented, the nature of the active sites for Cu/Fe 3 O 4 remains debated and the role of the crystallite size of Fe 3 O 4 has not been tackled. In this study, a wide range of Cu/Fe 3 O 4 catalysts were designed by hosting Cu species onto Fe 3 O 4 of two contrasting crystallite sizes (approximately 10 and 160 nm) and by utilizing different preparation methods (ammonia evaporation and deposition-precipitation). The evaluation of their catalytic WGS performances revealed a remarkable and previously undocumented phenomenon: the addition of Cu resulted in universal activity enhancements only for small Fe 3 O 4 crystals, while the larger analogues displayed decreased activity. This peculiar phenomenon can be explained by the creation of Cu–Fe 3 O 4 interfaces present in the iron oxides of small crystallite sizes. Thorough characterizations, such as advanced electron microscopic, in situ powder X-ray diffractions, in situ diffuse reflectance infrared Fourier transform spectroscopy, and computational studies, suggest strong electronic interactions between the different metal species, facilitated reductions of the individual oxides, and more favorable CO activation at the interfacial sites, all accounting for the promoted activity. [Display omitted] • Influence of Fe 3 O 4 crystallite size in water-gas shift reaction was examined. • Performance of Cu/Fe 3 O 4 in water-gas shift reaction was studied. • The formation of Cu–Fe 3 O 4 interfaces existed on small Fe 3 O 4 crystals. • Promotional effect of Cu was only found on small Fe 3 O 4 crystals. [ABSTRACT FROM AUTHOR]

Iron oxide-based ferrite ceramics, widely applied in high-frequency applications, are conventionally produced through high-temperature sintering processes, often resulting in grain growth and phase transformation. In this study, we used a cold sintering process (CSP) with oxalic acid (OA) as a solvent to consolidate iron oxide (Fe 3 O 4) ceramics at a low temperature of 160 °C. The OA-assisted CSP technique has demonstrated a remarkable capacity to facilitate the dissolution and redeposition of iron oxide ions, leading to the interconnection of Fe 3 O 4 particles, forming densely packed ceramics even at low-temperature sintering. Importantly, CSP maintained particle sizes and hindered phase transitions of Fe 3 O 4. The OA concentrations in CSP had a minimal impact on crystal structure and magnetic properties, but it significantly enhanced microstructural features, density, hardness, and electrical resistance. Compared to reference samples prepared without an aqueous solution or with water alone, the CSP-prepared Fe 3 O 4 ceramics with OA exhibited substantially improved density (a relative density of ∼80 %), mechanical properties (Vickers hardness of 3.5–4.0 GPa), magnetic properties (saturation magnetization >70 emu/g), and electrical resistance (electrical conductivity ∼10−3 S/cm at 102–106 Hz). These findings demonstrate a novel approach to fabricating Fe 3 O 4 ceramics at significantly lower temperatures while still achieving properties comparable to those sintered at high temperatures. [ABSTRACT FROM AUTHOR]

This work designed a mesoscale method of multi-step reduction of Fe 2 O 3 with H 2 based on Lattice Gas Cellular Automata (LGCA). Particles in the LGCA were marked to distinguish all the reactants, intermediates, products, and inert. A self-organized evolutionary mechanism is designed. The hydrogen reduction of Fe 2 O 3 in the temperature range of 460–550 °C and 650–800 °C was simulated. Results show that the intermediate product Fe 3 O 4 was found in both conditions, and its mass fraction quickly reach a peak at ∼0.8 and gradually decrease thereafter. An "induction period" can be identified in the initial stage of the reaction at 650–800 °C, where the reduction rate is slow due to the hindered formation of FeO. The porosity inside the Fe 2 O 3 particles increases continuously through the reduction process, resulting in significant changes in the flow field around the particles. Consequently, the wake vortex gradually decreases and disappears eventually. • The multiple step reduction of Fe 2 O 3 by hydrogen is investigated in mesoscale. • A mesoscale method with self-organized evolutionary mechanism is developed. • Three obvious reaction rate transitions can be identified at 650–800 °C by the method. • The flow field is altered from internal structural of Fe 2 O 3 changes during reduction. [ABSTRACT FROM AUTHOR]

The utilization of nanoparticles to enhance bacterial activity and boost hydrogen production in fermentation processes has gained significant attention due to their unique properties such as high specific surface area and quantum size. This research aimed to improve the biohydrogen yield from food waste by adding iron oxide nanoparticles (Fe 3 O 4) at various concentrations (50, 75, 100, 150, and 200 mg/l) and titanium dioxide (TiO 2) at different amounts (25–150 mg/l) to a single-stage hybrid (dark/photo) fermentation reactor. After obtaining the optimal amount of these two nanoparticles, the effect of synergic addition of nanoparticles on hydrogen production yield, was investigated at ratios of Fe 3 O 4 /TiO 2 = 50/50 and 100/50 mg/mg. At the ratio of Fe 3 O 4 /TiO 2 = 100/50, the cumulative hydrogen production and yield of hydrogen have increased from 1613 to 3392 ml and 101.60 to 213.66 mlH 2 /gVS, respectively, compared to the control experiment. We also found that the COD removal rate has enhanced from 28% to 40.1%. In the optimal value, the bacterial growth lag phase has also remarkably decreased from 8.19 to 4.81 h. • Synergic application of TiO 2 and Fe 3 O 4 significantly increased biohydrogen purity and production yield. • TiO 2 played an important role in the activity of bacteria in the photo fermentation process. • Fe 3 O 4 played an important role in the dark fermentation system. • Nanoparticles may act as a scaffold for enzyme and substrate binding. • Optimal nanoparticle concentration may differ for different bioreactors. [ABSTRACT FROM AUTHOR]

Chemical Looping Hydrogen (CLH) allows the direct production of pure hydrogen exploiting the redox properties of Fe, with high flexibility on the type of reductant used. In this work, a highly pure hydrogen stream suitable for the direct use into Proton Exchange membrane Fuel Cells was produced, using bioethanol as renewable fuel. The influence of both redox temperature (675°C–750 °C) and chemical composition of the Fe-based particles (2 wt% and 40 wt% of alumina added) on the carbon formation rate during reduction step was also deeply analyzed. Al 2 O 3 changed both Fe x O y redox kinetics and equilibrium phases, leading to a complete iron deactivation at high Al 2 O 3 concentration. The addition of an air oxidation step (3 steps CLH) is fundamental to restore the redox activity, with a constant efficiency of about 30% at 750 °C for 10 cycles. Furthermore, Al 2 O 3 promotes the ethanol conversion into carbon, undermining the hydrogen purity. [Display omitted] • Pure H 2 suitable for PEMFCs is obtained using bioethanol as renewable fuel. • The influence of Fe/Al interaction on H 2 yields and H 2 purity was studied. • 3 steps CLH allows the use of Fe 2 O 3 -40 wt% Al 2 O 3 with no reduction in performance. • Fe 2 O 3 -2 wt% Al 2 O 3 withstands 10 redox cycles in the temperature range 675–750 °C. • A process efficiency of 30% was achieved at 750 °C for 10 consecutive redox cycles. [ABSTRACT FROM AUTHOR]

Fe 2-x Sn x O 3 structures grown by RF-DC magnetron co-sputtering. The band gap of Fe 2 O 3 , SnO 2 , Fe 2-x Sn x O 3 structure was calculated as 2.86, 4.06, 2.77 eV, respectively. The Fe 2 O 3 thin film has shown a tetragonal as well as the SnO 2 structure, however, the Fe 2-x Sn x O 3 (0 < x < 1) has shown rhombohedral structure. XPS measurements have shown change in binding energy which is due to the electron exchange of tin-iron with oxygen, and iron - tin oxide structure. This binding energy increases slightly with the chemical environment effect. The films were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM). In AFM images was seen that the iron oxide structure was pyramidal and the tin oxide structure was spherical, similar to the SEM image. The response of the film to hydrogen gas was measured at flow values of 100, 500 and 1000 ppm at 300 °C. Fe 2 O 3 thin films show 46%, SnO 2 61% and, Fe 2-x Sn x O 3 6.5% response to 1000 ppm H 2 gas. It is seen that the gas sensor response was affected by the morphological and structural features of the grown film. Current vs. time graph for thin films gas sensor. [Display omitted] • Thin films were successfully grown by RF-DC co-sputtering system. • Metal oxide hydrogen gas sensor devices were measured depending on different grown structures. • Fe 2 O 3 , SnO 2 , Fe 2-x Sn x O 3 thin films show 46%, 61%, 6.5% response to 1000 ppm H 2 gas. • Iron oxide and tin oxide have n-type carrier, while iron tin oxide has p-type carrier. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bioenergy recovery from a continuous two-stage process was greatly improved by IO. • IO promoted butyrate metabolic pathway in hydrolytic–acidogenic stage. • IO stimulated the activity of hydrolytic enzyme, dehydrogenase and coenzyme F420. • IHT between Syntrophomonas and Methanobacterium was enhanced by IO. • IO triggered DIET between Geobacter sulfurreducens and Methanosarcina. The food waste (FW) digestion performance can be enhanced by introducing iron oxide (IO) into digesters. However, the role of IO in continuous two-stage digesters in enhancing the FW anaerobic digestion remains unclear. In this study, the effect of IO on the bioenergy recovery from a two-stage digestion process was investigated. The bioenergy recovery was significantly increased by up to 208.43 % with IO addition. The activities of dehydrogenase, α-amylase, and protease increase by 0.82–1.44, 7.24–14.56 and 7.97–20.45 times, respectively, as compared with that of the blank. With IO addition, the metabolic pathway in hydrolytic–acidogenic (HA) reactor shifted from lactic acid fermentation to butyric fermentation, which promoted stable methane production in methanogenic (MG) reactor. The activity of coenzyme F420 increased by 19.19–39.01 times, indicating that IO facilitated FW digestion by promoting hydrogenotrophic methanogenesis. The enhancement in the enzyme activity was attributable to the Fe2+ generated by dissimilatory iron reduction. According to the microbial analysis, IO enhanced interspecies hydrogen transfer between Methanobacterium and Syntrophomonas. Furthermore, IO improved direct interspecies electron transfer between Geobacter sulfurreducens and Methanosarcina. The effluent recirculation strategy greatly facilitated the hydrolysis and acidification of FW, which was critical for improving the two-stage process performance. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 is an appealing anode material due to its high specific capacity (1007 mAh g−1), low cost, natural abundance, and nontoxicity. However, its unstable structure during cycling processes has hindered its potential. In this study, we present a "green" synthesis method to fabricate stable porous Fe 2 O 3 encapsulated in a buffering hollow structure (p -Fe 2 O 3 @ h -TiO 2) as an effective anode material for Li-ion batteries. The synthesis process only involves glucose as an "etching" agent, without the need for organic solvents or difficult-to-control environments. Characterizations of the nanostructures, chemical compositions, crystallizations, and thermal behaviors for the intermediate/final products confirm the formation of p -Fe 2 O 3 @ h -TiO 2. The synthesized Fe 2 O 3 anode material effectively accommodates volume change, decreases pulverization, and alleviates agglomeration, leading to a high capacity that is over eleven times greater than that of the as-received commercial Fe 2 O 3 after a long cycling process. This work provides an attractive, "green" and efficient method to convert commercially abundant resources like Fe 2 O 3 into effective electrode materials for energy storage systems. [ABSTRACT FROM AUTHOR]

An advanced version of the solution combustion synthesis (SCS) method was developed to prepare iron oxide (IO) nanoparticles, through controlling the agglomeration, size and shape of nanoparticles by assisting a cationic surfactant, "cetyltrimethylammonium bromide (CTAB)" and ethanol. Various IO nanoparticles were prepared in the presence of different CTAB:ethanol molar compositions of 0:0, 0.27:0, 0.55:0, 0.27:17.1, 0.55:17.1 and 0.82:17.1. The morphological evolution from agglomerated-shape particles to the well-dispersed as well as the size- and shape-controlled particles depended directly on the CTAB:ethanol molar composition. A shift from ferromagnetic behavior to superparamagnetic was observed by the application of CTAB along with ethanol, where the lowest blocking temperature (T b , 60 K), highest saturation magnetization (M s , 83.5 emu g−1), zero coercivity and remanance magnetization were revealed for the particles prepared by CTAB:ethanol molar compositions of 0.55:17.1. These particles showed an acceptable specific absorption rate (SAR) value (320 W g−1) as well as no obvious hemolytic and cytotoxic effects. This work provides new insights into advancing the SCS method and thus controlling the morphology, size and shape of metal oxide nanoparticles. [Display omitted] • Controlling the agglomeration, size and shape of nanoparticles in SCS method. • Structural and magnetic properties of particles depended on the CTAB:ethanol ratio. • The agglomerated-free, size- and shape-controlled IO-EC2 structure was developed. • IO-EC2 represented an acceptable SAR value, and no hemolytic and cytotoxic effects. [ABSTRACT FROM AUTHOR]

Materials composed of various constituents with distinct physical or chemical features are named composites. Merging components in the composite structure leads to new properties creation or the intrinsic properties magnification of the components, or synergetic effects. Here, the ternary nanocomposite of copper, nickel, and iron oxides was electrodeposited on the glassy carbon electrode (GCE) surface to facilitate the ethanol electro-oxidation reaction (EOR) and overcome the electrode fouling problem while prolonging its efficiency. The GCEs were modified by three different procedures and activated by CV cycling in an alkaline solution, and their electro-catalytic activity was tested toward EOR. The ternary electrocatalysts prepared by two-steps electrodeposition of their components (Ni,Fe 2 O 3 /Cu and Cu/Ni,Fe 2 O 3) demonstrated higher peak current and more negative peak potential (E pa = 476 mV, I pa = 492 μA, and E pa = 510 mV, I pa = 644 μA, respectively) than the binary electrocatalyst of Ni,Fe 2 O 3 toward EOR. The best electro-catalytic efficiency was acquired for the simultaneous electrodeposition of nano Cu, Ni, and Fe 2 O 3 on the GCE surface (Cu,Ni,Fe 2 O 3 , E pa = 530 mV, I pa = 3179 μA). The physicochemical and electro-catalytic characterizations of the fabricated electrocatalysts were evaluated by various techniques. The fast and facile engineered design of the GCE modification with the ternary Cu,Ni,Fe 2 O 3 components led to a high current density of about 101 mA/cm2 with increased tolerance against poisoning intermediates resulting in longtime stability for EOR in alkaline media. The synergistic effect between nano Ni, Cu, and Fe oxides provided promising properties for the EOR pursuing the construction of a powerful device with commercialization potential. • On-step electrodeposition of Cu,Ni,Fe 2 O 3 ternary nano-composite • Improvement of the electron transfer kinetic of EOR • High tolerance against poisoning intermediates and longtime stability for EOR • Promising electro-catalytic performance of Cu,Ni,Fe 2 O 3 /GCE for EOR • Achievement of a high current density of ∼101 mA/cm2 for EOR [ABSTRACT FROM AUTHOR]

A simple and easily operated supercritical CO 2 dryer was designed and manufactured with the aim of producing high-surface-area mesoporous α-Fe 2 O 3 (hematite) and NiO aerogels. The gels were synthesized by a sol−gel method with the aid of propylene oxide (PO), as the gelation agent, and then dried and calcined at different conditions. The effects of drying and calcination conditions on the physicochemical properties of the final aerogels were investigated using X-ray diffraction (XRD), N 2 adsorption-desorption, Fourier-transformed infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FE-SEM) analyses. It was demonstrated that α-Fe 2 O 3 and NiO aerogels with high surface areas and mesoporosities could be successfully synthesized using the home-made supercritical CO 2 dryer. Supercritical drying of the gels resulted in α-Fe 2 O 3 (186 m2/g) and NiO (178 m2/g) aerogels with 186% and 34% higher surface areas, respectively, than xerogels obtained via simple drying at 80°C using a laboratory oven. In addition, the results showed that supercritical CO 2 drying could enhance preservation of the porous network of the oxide nanostructures at high calcination temperatures via suppression of sintering phenomenon. Calcination of α-Fe 2 O 3 and NiO aerogels at 600°C yielded 225% and 53% higher surface areas than the corresponding xerogel, confirming the significance of drying step in the sol − gel method. Asphaltene adsorption from a model oil with asphaltene concentration of 3000 ppm indicated that the aerogels possessed higher adsorption capacities for the bulky asphaltene molecules than xerogels calcined at the same temperature of 600°C, which was due to their enhanced textural properties. [ABSTRACT FROM AUTHOR]

Multicore magnetic iron oxide nanoparticles, nanoflowers (NFs), have potential biomedical applications as efficient mediators for AC-magnetic field hyperthermia and as contrast agents for magnetic resonance imaging due to their strong magnetic responses arising from complex internal magnetic ordering. To realise these applications amenable surface chemistry must be engineered that maintain particle dispersion. Here a catechol-derived grafting approach is described to strongly bind polyethylene glycol (PEG) to NFs and provide stable hydrogen-bonded hydrated layers that ensure good long-term colloidal stability in buffers and media even at clinical MRI field strength and high concentration. The approach enables the first comprehensive study into the MRI (relaxivity) and hyperthermic (SAR) efficiencies of fully dispersed NFs. The predominant role of internal magnetisation dynamics in providing high relaxivity and SAR is confirmed, and it is shown that these properties are unaffected by PEG molecular weight or corona formation in biological environments. This result is in contrast to traditional single core nanoparticles which have significantly reduced SAR and relaxivity upon PEGylation and on corona formation, attributed to reduced Brownian contributions and weaker NP solvent interactions. The PEGylated NF suspensions described here exhibit usable blood circulation times and promising retention of relaxivity in-vivo due to the strongly anchored PEG layer. This approach to biomaterials design addresses the challenge of maintaining magnetic efficiency of magnetic nanoparticles in-vivo for applications as theragnostic agents. Application of multicore magnetic iron-oxide nanoflowers (NFs) as efficient mediators for AC-field hyperthermia and as contrast agents for MR imaging has been limited by lack of colloidal stability in complex media and biosystems. The optimized materials design presented is shown to reproducibly provide PEG grafted NF suspensions of exceptional colloidal stability in buffers and complex media, with significant hyperthermic and MRI utility which is unaffected by PEG length, anchoring group or bio-molecular adsorption. Deposition in the selected pancreatic tumour model mirrors liposomal formulations providing a quantifiable probe of tissue-level liposome deposition and relaxivity is retained in the tumour microenvironment. Hence the biomaterials design addresses the longstanding challenges of maintaining the in vivo magnetic efficiency of nanoparticles as theragnostic agents. [Display omitted] [ABSTRACT FROM AUTHOR]

Microparticles of iron oxide (MPIOs) are increasingly used for contrast generation in magnetic resonance imaging (MRI). In particular, Dynabeads® MyOne™ Tosylactivated MPIOs have enabled sensitive and targeted molecular imaging, e.g. , to detect vascular inflammation. For the first time we measured the relaxivities as well as the molar susceptibility χ M of these MPIOs at 7 T in agarose gels. They are r1 = 0.69 ± 0.03 s−1/mM, r2 = 220 ± 6 s−1/mM, r2* = 679 ± 14 s−1/mM, and χ M = 0.66 ± 0.05 ppm/mM, when expressed with respect to the iron concentration. These material parameters are essential to optimize MRI protocols and progress toward quantitative imaging. To address the heterogeneous nature of the MPIO distributions over the size of a typical MRI voxel, we coupled the MPIOs to a fluorophore to create a bimodal phantom that can be imaged by both Light Sheet microscopy and MRI. In this phantom, the MPIOs produced contrast similar to that found in vivo. The submicron resolution of Light Sheet microscopy images provided a precise measurement of the MPIO spatial distribution in phantoms also imaged by MRI. MPIO aggregates occupying less than one MRI voxel were responsible for alterations in R2* and magnetic susceptibility χ across several MRI voxels. In these cases, the sum of R2* or χ over the affected MRI volume correlated better with the microscopically determined number of MPIOs. These findings were confirmed with simulations performed in the static dephasing regime. The microscopically determined MPIO distribution was also entered directly into the simulation framework, indicating that the bimodal phantom is a useful tool to test theoretical models against experimental measurements. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 has the advantages of unique magnetic stability and low biological toxicity, which can improve pollutants separation efficiency. MXenes are two-dimensional materials and easy surface functionalization that can provide suitable carriers for Fe 3 O 4. In this work, we synthesized magnetic MXene composites by a one-pot method that relies on doping Fe 3 O 4 particles onto Ti 3 C 2 MXene nanosheets by heat treatment. The Fe 3 O 4 /Ti 3 C 2 MXene was analyzed by SEM, XRD, FTIR and XPS techniques, which showed that the material has good tetracycline (TC) removal properties and magnetic separation ability. The results showed that the adsorption capacity of it was 46.42 mg g−1, and the removal efficiency of 0.06 g adsorbent for 50 mL of 30 mg L−1 TC could reach 92.1% in a wide pH range of 4–10, when the adsorption temperature was 25 °C, and the adsorption time was 3 h. The adsorption data were consistent with Langmuir and the proposed second-order kinetic model, and the thermodynamic experiments confirmed that the adsorption of TC was a monolayer physicochemical adsorption coexisting heat-trapping process (ΔH = 15.72 kJ mol−1). In addition, the adsorption of TC by Fe 3 O 4 /Ti 3 C 2 MXene was attributed to the synergistic effect of electrostatic attraction, hydrogen bonding and π-π packing. In conclusion, the saturation magnetization of Fe 3 O 4 /Ti 3 C 2 MXene is 27.3 emu/g and it can not only be separated from water using its strong magnetic properties to avoid secondary contamination, but also can be used as a promising material to effectively remove antibiotics from aqueous media. [Display omitted] • A kind of magnetically recyclable, regenerative adsorbent for tetracycline adsorption (Q max = 46.42 mg g−1) has been obtained. • The mechanisms of Fe 3 O 4 /Ti 3 C 2 adsorbing tetracycline: endothermic adsorption; the quick absorption of pollutants is facilitated by the electrostatic interactions, π−π bonds and hydrogen bonds. • The adsorption occurs over a wide pH range of 4–10. [ABSTRACT FROM AUTHOR]

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

We report the effective synthesis of polyaniline (PANi)-layered nitrogen-doped carbon-coated Fe 3 O 4 (FNC@PANi) nanocapsules (NCs) for electrocatalysis of oxygen evolution reaction (OER) as well as anode material for lithium (Li)-ion batteries (LIBs) via a simple hydrothermal method and oxidative polymerization technique. The prepared FNC@PANi NCs revealed a dual core-shell structure, in which an intermediate carbon layer allowed excellent electrical conduction between the Fe 3 O 4 NCs and PANi. The dual core-shell structure also allowed the Fe 3 O 4 NCs to expand freely during the Li-ion insertion/extraction and OER processes without breaking the outer layer, thus providing a high surface area (147.85 m2 g−1) and enhanced electrical conductivity. These properties facilitate the application of the dual core-shell FNC@PANi NCs as an advanced electrode material for LIBs, delivering a high reversible specific capacity of 1556.48 mAh g−1 at 0.1 A g−1, excellent rate performance (896.96 mAh g−1 at 1 A g−1), and durable cycling life (680.12 mAh g−1 at 5 A g−1 for 3000 cycles). The dual core-shell FNC@PANi NCs exhibited high electrocatalytic activity in the OER, with a small Tafel slope of 108.7 mV dec−1 owing to synergistic effects between the copious active sites of the Fe 3 O 4 NCs and the carbon core-shell structure and a modest overpotential of 219 mV at 10 mA cm−2. The electrodes showed excellent stability over 10 h, as determined by chronopotentiometry at 10 mA cm−1. The resultant dual-core-shell FNC@PANi NCs are efficient iron-oxide-based electrode materials for LIBs and OER electrocatalysts. Facile solvothermal method and chemical oxidative polymerization technique are reported for the synthesis of bifunctional electrocatalyst and high-performance LIB anode material, i.e., dual core-shell polyaniline layered nitrogen-doped carbon coated Fe 2 O 3 nanocapsules (dual core-shell FNC@PANi NCs). Compared to its counterparts, this FNC@PANi NCs electrode delivers excellent energy storage properties along with higher OER behavior. [Display omitted] • A bifunctional electrode material for lithium-ion battery (LIB) and oxygen evolution reaction (OER) electrocatalyst, namely dual core-shell FNC@PANi NCs, was synthesized via a hydrothermal method. • The material serves as an advanced LIBs electrode, exhibiting impressive cycling stability, excellent rate capability, and durable cycling life. • As an OER electrocatalyst, the FNC@PANi NCs demonstrate significant catalytic activity, evidenced by small Tafel slope and modest overpotential. [ABSTRACT FROM AUTHOR]

The respiratory effects of particulate matter (PM) in subway station platforms or tunnels have attracted considerable research attention. However, no studies have characterized the effects of subway PM on allergic immune responses. In this study, iron oxide (α-Fe 2 O 3 and Fe 3 O 4) particles—the main components of subway PM—were intratracheally administered to BALB/c mice where ovalbumin (OVA) induced allergic pulmonary inflammation. Iron oxide particles enhanced OVA-induced eosinophil recruitment around the bronchi and mucus production from airway epithelium. The concentrations of type 2 cytokines, namely, interleukin (IL)-5 and IL-13, in bronchial alveolar lavage fluids were increased by iron oxide particles. Iron oxide particles also increased the number of type 2 innate lymphoid cells and CD86+ cells in the lung. Moreover, phagocytosis of particles in lung cells was confirmed by Raman spectroscopy. In a subsequent in vitro study, bone marrow-derived antigen-presenting cells (APCs) isolated from NC/Nga mice were exposed to iron oxide particles and OVA. They were also exposed to outdoor ambient PM: Vehicle Exhaust Particulates (VEP) and Urban Aerosols (UA) as references. Iron oxide particles promoted the release of lactate dehydrogenase, C-X-C motif chemokine ligand 1 and IL-1α from APCs, which tended to be stronger than those of VEP. These results suggest that iron oxide particles enhance antigen presentation in the lungs, promoting allergic immune response in mice; iron oxide particles-induced death and inflammatory response of APCs can contribute to allergy exacerbation. Although iron oxide particles do not contain various compounds like VEP, iron oxide alone may have sufficient influence. [Display omitted] • α-Fe 2 O 3 /Fe 3 O 4 particles were used as the components of subway particulate matters. • Iron oxide particles exacerbated allergic airway inflammation in mice. • Iron oxide particle-enhanced antigen-presenting can trigger allergies. • Iron oxide particles increased type 2 innate lymphoid cells in murine lungs. • α-Fe 2 O 3 and Fe 3 O 4 were detected in lung macrophages by Raman spectroscopy. [ABSTRACT FROM AUTHOR]

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

Oxide materials are important for gas sensing applications. Unfortunately, most of the synthesis methods use many toxic chemicals and need long calcination at high temperatures. Thus, developing simple and green synthesis processes, which can be performed fast and at low temperatures, is imperative for both industrial manufacturers and our environment. Here, our fast and green synthesis method based on low-power laser sintering for producing FeO x (with Fe 2 O 3 as the main composition) is presented. Besides, FeO x particles were decorated on reduced graphene oxide (RGO) to form a resistive sensor. Notably, our FeO x material can reduce the response of RGO toward acidic gas (NO 2) but it enhances the RGO response toward the basic NH 3 gas. Particularly, our hybrid FeO x /RGO sensor can detect NH 3 gas at above 2 ppm under dry and humidified conditions (<85 % RH). That effect of FeO x is found due to the formation of alpha-phase Fe 2 O 3 which acts as a p-type semiconductor, which is explored and explained in the discussion section. Finally, our findings not only reveal the potential of our hybrid sensing materials for practical NH 3 sensing applications but also confirm the usefulness of laser-sintering to produce catalytic oxide materials environmentally friendly and at low cost. [Display omitted] • Fast and green production method of iron oxides (Fe 3 O 4 or Fe 2 O 3) is reported. • FeO x was directly formed on RGO resistive gas sensors via laser sintering. • p-type FeO x tuned the sensing behavior of RGO materials toward NH 3 basic gas. • The hybrid FeO x /RGO sensor can work at RT and under a wide humidity range. [ABSTRACT FROM AUTHOR]

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

The forefront hydrogel nanocomposite, resulting from the integration of Agarose (Aga), Graphene Quantum Dots (GQDs), and α-Fe2O3, offers a novel approach to pH-responsive drug delivery, specifically tailored for the controlled release of Quercetin (QC), a potent anti-cancer agent. The incorporation of the surfactant Span 80 enhances the unique properties conferred by the integration of α-Fe2O3 into the Aga-modified GQDs hydrogel, resulting in the production of stable nanocarriers that improve QC retention. Thorough analyses utilizing Fourier-transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD) shed light on the characteristics of the nanocarriers. The presence of nanoparticles within the nanocarriers was confirmed by Dynamic Light Scattering (DLS), revealing a spherical morphology with an average size of approximately 279.04 nm and a polydispersity index (PDI) of 0.24. Measurements of the zeta potential indicated a positive surface charge of about 52.8 mV. In the Aga/GQDs configuration, loading and encapsulation efficiencies reached 35 % and 67 %, respectively. With the inclusion of α-Fe2O3, improvements were observed, with loading and encapsulation efficiencies reaching 47 % and 86.25 %, respectively, surpassing previous values. Cellular tests conducted on the HepG2 cell line demonstrated the heightened anticancer efficacy of QC-loaded nanoparticles while assessing potential adverse effects. These results underscore the exciting potential of the nanocarrier as a promising strategy for cancer treatment. • Development of a pH-responsive hydrogel nanocomposite integrating Agarose, Graphene Quantum Dots, and α-Fe2O3 for controlled drug delivery. • Optimization of loading and encapsulation efficiencies through the inclusion of α-Fe2O3, surpassing previous benchmarks. • Demonstrated efficacy against HepG2 cancer cells, highlighting the potential of the nanocomposite as a promising strategy for cancer treatment. [ABSTRACT FROM AUTHOR]

Reverse loading of inert Al 2 O 3 support onto reactive FeO x nanoparticles generates nanocomposite with unusually improved reactivity and stability for H 2 O 2 activation and pollutant removal, compared to the analogue traditional nanocomposite which was prepared via the loading of FeO x nanoparticles onto inert Al 2 O 3 support. [Display omitted] • Reverse loading of inert Al 2 O 3 onto reactive FeO x to generate FeO x @Al 2 O 3 -R. • FeO x @Al 2 O 3 -R shows much improved reactivity in H 2 O 2 activation than its traditional analogue. • FeO x @Al 2 O 3 -R also shows greatly enhanced stability featuring suppressed ion leaching. • The inert Al ions modify the electronic environment and properties of the surface Fe reactive sites. Developing heterogeneous iron-based catalysts with superior reactivity and stability is a long-term goal for hydrogen peroxide (H 2 O 2) activation in Fenton-like technique for water remediation. Supported iron-based nanocomposites are of great interest due to their earth abundance, environmental friendliness, and tunable structure. However, existing iron-based Fenton catalysts are normally designed via the loading of iron-derived nanoparticles onto various inert substrates, where the surface reactive sites are hardly affected by the substrate. Here, we report the first example of reversely loaded FeO x -Al 2 O 3 nanocomposite via overturning the loading direction, i.e., loading inert Al 2 O 3 support onto reactive FeO x nanoparticles. The resultant FeO x @Al 2 O 3 -R catalyst demonstrated much improved reactivity for H 2 O 2 activation and bisphenol A removal (by 14 times in terms of first-order rate constant) than its analog FeO x /Al 2 O 3 -T, which was prepared via the loading of FeO x nanoparticles onto inert Al 2 O 3 support. Moreover, FeO x @Al 2 O 3 -R exhibited excellent stability with Fe leaching only one sixth of FeO x /Al 2 O 3 -T. Systematic characterization results revealed that the inert Al ions modify the electronic environment and properties of the surface Fe reactive sites. This work provides an alternative reverse loading strategy to traditional loading method for the preparation of iron-based nanocomposite catalyst that is highly efficient for H 2 O 2 activation and pollutant removal. [ABSTRACT FROM AUTHOR]

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

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

• Co 2 O 3 and CeO 2 were doped in Fe 2 O 3 as anode material of Lithium-ion battery. • The cobalt and cerium oxides doping was beneficial to particles refinement. • Co 2 O 3 and CeO 2 doping could significantly improve the electrochemical stability. Lithium-ion batteries offer several advantages, including high specific energy, extended lifespan, portability, and environmental friendliness. Transition metal oxides are attractive candidates for negative electrode materials due to their higher theoretical specific capacity. To address issues related to poor stability and volume expansion, cobalt trioxide and cerium oxide were introduced as dopants in iron oxide. This study involved the preparation of Co 2 O 3 -Fe 2 O 3 and CeO 2 -Co 2 O 3 -Fe 2 O 3 composites, followed by structural characterization and investigation of their electrochemical properties. The doping of cobalt and cerium oxide proved advantageous in refining particle size. Notably, 1% Co 2 O 3 -Fe 2 O 3 particles displayed uniform sizing and tight binding. Additionally, the sample containing 0.05% CeO 2 exhibited the smallest particle size and a more homogeneous distribution. Furthermore, cobalt and cerium oxide doping significantly improved electrochemical stability. The discharge capacity of 1% Co 2 O 3 -Fe 2 O 3 and 0.05% CeO 2 -1% Co 2 O 3 -Fe 2 O 3 after undergoing 100 constant-current charge and discharge cycle respectively remained at 553.17 mAh/g, 698.57 mAh/g. As a negative electrode material in lithium-ion batteries, the composite oxide 0.05% CeO 2 -1% Co 2 O 3 -Fe 2 O 3 demonstrated superior reversibility and stability during the process of lithium-ion insertion and removal, while also exhibiting low contact resistance and charge transfer resistance. [ABSTRACT FROM AUTHOR]

The conductivity spectra of the iron oxide Ba 0.25 Sr 0.25 Fe 0.25 O 4 revealed that sample exhibits a semi-conductor behavior within the temperature and frequency. Based on the direct current analysis, charge carrier transport was assisted by a disorder energy below θ D / 4. For θ D / 4 ≤ T ≤ θ D / 2 , electrical conductivity was attributed to the contribution of the Mott-VRH mechanism. However, for T ≥ θ D / 2 , conduction phenomena were supported by the thermal activation of the small polaron hopping mechanism. At higher frequencies, the electrical characteristics of our sample were clarified through the application of a superlinear power law. The contributions of different conduction processes were predicted using temperature dependent frequency exponents. The hopping energy was found to decrease as the frequency increased, a trend that can be linked to variations in the polaron radius. The impedance results validate the involvement of the resistive grain boundary in the electrical properties and indicate the presence of multiple electrical relaxation phenomena in the Ba 0.25 Sr 0.25 Fe 0.25 O 4 sample. [ABSTRACT FROM AUTHOR]

In this study, the influence of temperature (40, 60 and 80 ∘C) and light exposure on the dissolution of ▪ particles in aqueous, oxalic acid (0.45 mol/l) is experimentally investigated. A novel experimental setup, consisting of a vessel with undistorted optical access, allows the recording of dissolving particles using a video system. During post-processing, particles are automatically identified and their size and morphology are determined. Binning particles into discrete time-steps during the reaction yields heavy-tailed distributions characterized by a single parameter estimated through a maximum-likelihood estimation of a doubly truncated power-law fit. For the first time, up to three consecutive phases could be identified during the dissolution process of iron oxide particles. The contribution of each phase to the overall dissolution process is determined by a complex interplay between particle fragmentation, different reaction mechanisms and solid product formation. The initial phase is characterized by the fragmentation of larger particles with a more complex morphology, resulting in greater surface area available for reaction. In the second phase, fragmentation is less apparent and the available particle surface area is reduced. The transition to the third phase relies primarily on the supply of short wavelength light, which leads to the formation of a solid product that can increase the tracked particle diameter. • Up to three consecutive phases during iron oxide particle dissolution. • First phase dominated by particle fragmentation leading to increasing surface area. • Second phase dominated by surface area reduction, less by particle fragmentation. • Third phase occurs only at low temperatures and short-wavelength light exposure. • The third phase is characterized by solid product formation. [ABSTRACT FROM AUTHOR]

The unsaturated behavior of permeable reactive barriers (PRB) is a critical component in predicting the removal efficiency through the adsorption of contaminants. This study investigates the framework to estimate the soil water characteristic curve (SWCC) and hydraulic conductivity function (HCF) for iron oxide-coated sand (IOCS) and zeolite, which are common materials used in PRBs. A multistep outflow (MSO) experiment was performed and the results of the MSO experiment were used to optimize associated parameters in Kosugi's SWCC and HCF. In addition, three scenarios of optimization analysis were investigated to evaluate the best-fitting model for estimating SWCC and HCF. The low root mean square error (RMSE) of fitted parameters indicates the Kosugi model well described the observed suction profiles in MSO experiments. In addition, the lowest RMSE and coefficient of variation suggested the inclusion of the additional parameter β provided the best estimation of the three materials (clean sand, IOCS, and zeolite). The physically reasonable estimation of SWCC and HCF of the three materials from the optimized parameters suggests the proposed framework is a reasonable model for the unsaturated behavior of PRBs. [Display omitted] • Multistep outflow experiment of soils was performed for predicting SWCC. • Iron oxide coated sand and zeolite were selected for PRB applications. • Fitting parameters in Kosugi's SWCC was optimized from MSO experiment. • Reliable prediction of SWCC and HCF of clean sand, IOCS, and zeolite was obtained. [ABSTRACT FROM AUTHOR]

• Reduced graphene oxide/iron oxide nanocomposites-based humidity sensors exhibit superior sensing capabilities towards varying humidity levels compared to rGO. • The rGO/Fe 2 O 3 NC humidity sensors showed enhanced sensitivity, excellent sensing response, and quick response/recovery time towards different humidity level. • The humidity sensors displayed long-term stability and excellent selectivity towards different %RH levels. For the humidity sensing, rGO/Fe 2 O 3 nanocomposites were synthesized via an ultrasonic-assisted method, utilizing Hummers' and co-precipitation techniques for rGO and Fe 2 O 3 synthesis. XRD analysis confirmed the formation of rGO and rhombohedral Fe 2 O 3 NPs, while SEM revealed varied (rough sheet-like and dense compact) morphologies. UV–VIS spectra indicated characteristic absorption peaks for rGO, Fe 2 O 3 NPs, and their NCs. In addition, FTIR spectra validated graphene oxide reduction and Fe 2 O 3 NPs/NCs formation. Humidity sensing was assessed across 40–80 % RH at varying frequencies (100 Hz-10 kHz), with 100 Hz identified as the optimal frequency due to water molecule polarization limitations at higher frequencies. The rGO/Fe 2 O 3 (70/30) NC exhibited a rapid response recovery time (5 s/10 s) and high sensitivity (2715.541 %), attributed to additional active sites provided by Fe 2 O 3 , enhancing water molecule adsorption and sensor sensitivity. The sensors demonstrated long-term stability and repeatability, showcasing promising potential for humidity sensing applications. [ABSTRACT FROM AUTHOR]

• The solid electrolyte of iron compound powder ingots can enhance battery capacity. • The ferrous chloride will be converted into Fe 8 O 8 (OH) 8 Cl 1.35 during the charge-discharge cycle. • After charging-discharging, an abnormal layer forms at the interface of solid electrolyte and electrode, leading to interface expansion, cracks, and reduced electrode adhesion. This study investigates a Fe/SSE/GF battery. Iron (Fe) as cathode material contains higher electrical capacity and competitive advantages. The solid-state electrolyte (SSE) material is sodium silicate powder mixed with iron compound powders. There are four types of iron compounds: 1) iron oxide, 2) chlorinated/Na-rich iron oxide, 3) Cl-rich iron oxide, 4) ferrous chloride, which are compared with sodium silicate powder. The negative electrode material is graphite film (GF). According to experiments, converting iron into iron oxide or ferric chloride can enhance battery capacity (beyond 200 mAh/g) and cycle life. The reliability of the Fe/SSE/GF battery was assessed by substituting sodium silicate powder with an iron compound electrolyte and adding binder (Polyvinyl Alcohol, PVA) into powder to enhance the performance of Fe/SSE/GF. This experimental research is not only innovative but also represents a significant milestone in the field of solid-state energy storage. [ABSTRACT FROM AUTHOR]

• LIC is made with C-coated iron oxide anode, heteroatom-doped porous carbon cathode. • AC800–3 cathode exhibits 154 F g−1 with 76 % retention after 10,000 cycles at 1 A g−1. • IO550 anode delivers 545 mAh g−1 with 76% capacity retention after 2000 cycles. • LIC exhibits 91 and 65 Wh kg−1 at power densities of 467 and 9350 W kg−1. • LIC retains ∼77% specific capacitance at 1 A g−1 for 5000 cycles. Lithium-ion capacitors (LICs) are promising devices to balance the space between lithium-ion batteries and supercapacitors by merging the battery-type anode and capacitor-type cathode materials in a single device. This work represents a lithium-ion capacitor containing in-situ carbon coating on mix-phase iron oxide from ferrocene as an anode and heteroatom-doping on porous carbon as the cathode. This type of cathode facilitates better wettability and a good contact area between the electrode and electrolyte, leading to a capacitance of 154 F g−1, retaining 76 % capacitance after 10,000 cycles at 1 A g−1. In contrast, the anode half-cell exhibits 545 mAh g−1 at 1 A g−1 and ∼76 % retention in capacity after 2000 cycles. This is because of nano-structuring and mix-phase iron oxide, allowing a conversion-type reaction to store Li-ions at a high rate, and carbon coating provides electronic conductivity and structural strength upon cycling. The full cell LIC demonstrates energy densities of 91 and 65 Wh kg−1 at power densities of 467 and 9350 W kg−1, respectively. This hybrid device can retain ∼77 % specific capacitance at 1 A g−1 for 5000 cycles. Furthermore, this study analyzes the practical application of LICs by evaluating impedance, self-discharge, and leakage current characteristics. [Display omitted] [ABSTRACT FROM AUTHOR]

• Nb5+-doped γ - Fe 2 O 3 were synthesized by sol–gel method. • As the Nb doping increases (≥3.8 at.%), the transformation from γ - Fe 2 O 3 to α-Fe 2 O 3 was suppressed up to 600 °C. • At elevated temperature of 700 °C, γ - Fe 2 O 3 went through full transformation to α-Fe 2 O 3 by expelling large amount of Nb to the surface of α-Fe 2 O 3 forming FeNbO 4. Nb5+-doped γ - Fe 2 O 3 was synthesized by sol–gel method followed by calcination at various temperatures from 200 to 700 °C, analyzed using Powder X-ray Diffraction (PXRD), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS) and Mössbauer Spectroscopy. PXRD results show the formation of γ - Fe 2 O 3 at 300 °C and it begins to transform to α-Fe 2 O 3 at 350 °C for pure and 2 at.% Nb-doped samples. As the Nb doping increases (≥3.8 at.%), the transformation was suppressed up to 600 °C. TEM EDS confirms the incorporation of Nb to γ - Fe 2 O 3 lattice in 9.1 at.% Nb sample calcined at 500 °C. At elevated temperature of 700 °C, γ - Fe 2 O 3 went through full transformation to α-Fe 2 O 3 by expelling large amount of Nb to the surface forming FeNbO 4. TEM EDS confirms the compositional change during this process with reduced Nb content in α-Fe 2 O 3 and Nb-rich nanoparticle on the surface of α-Fe 2 O 3. Superparamagnetic properties were observed for Mössbauer spectra when the Nb doping increased, which is caused by decreased particle size. The slight increase in internal magnetic field also indicated the transformation from γ - Fe 2 O 3 to α-Fe 2 O 3. High Nb doping with 20 and 40 at.% shows the formation of FeNbO 4 at lower temperature where limited or almost no Nb substitution in α-Fe 2 O 3 was detected by EDS. [ABSTRACT FROM AUTHOR]

Flexible supercapacitors (SCs) are pivotal in the development of wearable and portable electronic devices because of their exceptional power density, high charge/discharge rates, extended cycle life, lightweight, and flexibility. Graphene (G)-based macroscopic materials, such as one-dimensional fibers, two-dimensional films, and three-dimensional aerogels, exhibit a large specific surface area, low mass, excellent flexibility, and high conductivity. These properties make them highly suitable for use as flexible electrode materials in SCs. However, the low energy density of G-based materials hinders their application in certain fields. Iron oxide (Fe 2 O 3) has garnered considerable attention as a negative electrode material because of its low cost, high theoretical capacity, and environmentally friendly nature. However, its practical application is limited because of its poor cycling stability, easy agglomeration, and low electrical conductivity. The combination of G with Fe 2 O 3 to form a composite material not only addresses the issues of volume change and agglomeration associated with Fe 2 O 3 , but also establishes a robust conductive network that improves the electrochemical performance of composite electrodes. Therefore, the construction of SCs using Fe 2 O 3 /G composite electrodes has gained considerable research attention in recent years. We present a comprehensive review of the recent progress in the design of Fe 2 O 3 /G composites as electrode materials for flexible SCs. In addition, we discuss the current challenges and future prospects associated with the use of Fe 2 O 3 /G composites in flexible SCs. [Display omitted] • Recent progress in the design of iron oxide/graphene composites as electrode materials for flexible SCs is reviewed. • The fabrication methods are discussed in depth to provide insight into various development strategies. • The design strategies of iron oxide/graphene composites with different dimensions were comprehensively discussed. • Challenges in iron oxide/graphene composites-based flexible supercapacitors development were described. [ABSTRACT FROM AUTHOR]

[Display omitted] • MCGHCOF beads were prepared and used for fluoride adsorption studies. • MCGHCOF beads remove fluoride both in standard and field water. • MCGHCOF beads are regenerable and regenerated upto six cycles. • MCGHCOF beads are providing water with safe fluoride levels. The developed biocompatible materials like covalent organic frameworks (COFs) and hydroxyapatite acquire significant defluoridation capacity (DC). But because of their powder nature, creates column blockage, pressure drop during field investigations and difficult in separation after fluoride adsorption. To address these problems, COFs and hydroxyapatite were fabricated in the usable form of beads using chitosan, gelatin and iron oxide materials as magnetic chitosan–gelatin/hydroxyapatite/covalent organic frameworks (MCGHCOF) bio-beads were developed and it was potentially applied for the removal of fluoride from water. The MCGHCOF bio-beads surface and their properties were described with FTIR, EDAX, SEM and XRD analysis. The adsorption studies were performed under the batch method. The HCO 3 – ion has a vital inhibitory effect on DC and this may be because of the similar ionic size of fluoride and HCO 3 –. The enhanced DC of MCGHCOF beads was found to be 4992 mgF-.kg−1 in 30 min at pH 7. Isotherm experimental data of fluoride adsorption was apt with Langmuir isotherm than Fruendlich and D-R isotherm models. The defluoridation system is endothermic and its spontaneous nature was demonstrated with thermodynamic studies. Kinetic studies of experimental data of fluoride adsorption were well-fitted with pseudo-second-order and intraparticle diffusion. The complexation and electrostatic interaction play a predominant role in fluoride adsorption by MCGHCOF beads. The MCGHCOF bio-beads are stable and are reusable upto six cycles. The collected field water sample was examined using MCGHCOF beads and it reduced the fluoride concentration to the tolerable drinking water threshold as recommended by WHO (1.5 mg L−1). [ABSTRACT FROM AUTHOR]

In this work, we prepared sodium borate glass doped with different amounts of iron oxide (Fe 2 O 3) and samarium oxide (Sm 2 O 3). The effects of replacing Fe 2 O 3 with Sm 2 O 3 on the absorbance, optical band gap, Urbach energy, and radiation shielding parameters were studied. With further additions of Sm 2 O 3 , the optical band gap values increased from 2.50 to 2.67 eV, while Urbach energy values decreased from 0.49 to 0.42 eV. Further, we explored the effect of sunlight on the absorbance, optical band gaps, and Urbach energy at 90 min of irradiation time. With further exposure to sunlight, the values of the optical band gaps decreased and Urbach energy increased as the exposure time increased from 0 to 90 min. Moreover, the percent of change in absorbance, optical band gap, Urbach energy, refractive index, nonlinear refractive index and third order susceptibility for the glass samples containing the highest concentration of Sm 2 O 3 is insignificant (< 10 %). The small percentage changes in absorbance, optical band gap, and Urbach energy show that the glasses are stable when exposed to sunlight. On the other hand, the inclusion of higher concentrations of Sm 2 O 3 leads to improved radiation shielding capabilities, as seen by the increased values of the mass attenuation coefficient and half-value layer. Herein, the investigated glasses are both more transparent and more effective at shielding radiation; they're prime candidates for use in this field. • With further additions of Sm 2 O 3 , the optical band gap values increased while Urbach energy values decreased. • The absorbance of all glass specimens showed reduced behavior in the ultraviolet (UV) region. • With further exposure to sunlight, the values of the optical band gaps decreased and Urbach energy increased. • The percent of changes in all parameters of the glass sample containing the highest concentration of Sm 2 O 3 & 10 %. • With higher concentrations of Sm 2 O 3 , the increased values of the mass attenuation coefficient and half-value layer. [ABSTRACT FROM AUTHOR]

Macroporous strong acidic resin (D001) is restricted in Pb(II) removal from water due to the interference of common environmental cations. A novel modified D001 (nFeOOH@D001) was developed by loading nanoscale α-FeOOH (nFeOOH) with a facile ethanol-dispersion-impregnation method to improve Pb(II) removal from aqueous solution. Solid-phase analysis showed that α-FeOOH of 10–100 nm was evenly loaded onto D001. The nFeOOH@D001 maintained the electrostatic adsorption ability of D001, and obtained the complexation adsorption capacity of nFeOOH. The nFeOOH@D001 therefore achieved a 20.2% higher Pb(II) removal rate of 74.5% as compared to the D001 of 54.3%. Under the competition of Ca2+ and Mg2+ ions, the nFeOOH@D001 showed better selectivity for Pb(II) through the complexation of hydroxyl and ferrite groups on nFeOOH. The pseudo-first order kinetics and Langmuir-adsorption models well fitted the Pb(II) removal data, indicating a chemistry and monolayer adsorption process. This process depended on pH and achieved a Pb(II) removal over 65% within a pH range of 3–7. During cyclic test, used nFeOOH@D001 could be refreshed with acetic acid as eluent. Spent nFeOOH@D001 could be remodified with nFeOOH by the above impregnation method after stripping iron oxides with hydrochloric acid. The regenerated nFeOOH@D001 obtained a regeneration rate of 97.6% as compared to virginal nFeOOH@D001. The results demonstrated that the introduction of nFeOOH could effectively improve the performance of D001 for Pb(II) removal from water. [Display omitted] • Nanoscale goethite-modified resin (nFeOOH@D001) was prepared with ethanol-dispersion-impregnation. • α-FeOOH of 10–100 nm on D001 provided additional adsorption sites to compensate for its occupation. • Hydroxyl and ferrite groups on nFeOOH removed Pb(II) by complexation. • nFeOOH@D001 had higher Pb(II) selectivity as compared to D001. • nFeOOH@D001 exhibited excellent stability and reusability. [ABSTRACT FROM AUTHOR]

In this study, the anodized iron oxide films with micro-nano structure were prepared by a combination of heat treatment and anodization. The adjustment of these oxide films at the micron-scale was achieved by heat treatment on substrate to modify the position of the cementite and ferrite. The distribution and existing forms of carbon on cementite and ferrite determine the morphology of their respective anodization. It was found annealing at 300 °C can improve the crystallinity of iron oxide and maintain the original micro-nano structure. Although the crystal quality of iron oxide can be further improved with higher annealing temperature, it would result in the collapse of nanoporous structures and the reconstruction of the surface morphology. Furthermore, anodized samples made from those with lamellar ferrite and cementite show better specific capacitance. The iron oxide film on the annealed substrate obtained the highest specific capacitance of 35.3 mF/cm2 at a scan rate of 20 mV/s in our samples. [ABSTRACT FROM AUTHOR]

Among the diverse nanomaterials, polymer-based nanocomposites are gained more attention due to their high efficacy, target biological activities, biodegradability and biocompatibility—gum acacia (GA) - a polymer obtained from acacia trees-is considering the multifunctional nanocomposite synthesis. Distinctive Physico-chemical and biocompatibility properties of gum acacia are utilised to prepare a highly stable, biologically active, eco-friendly Nanocomposite. In this current investigation, gum acacia - poly ethylene glycol grafted iron oxide nanocomposite (GA-PEG-IONC) was synthesised by in situ green science principles. The synthesised Nanocomposite was evaluated against the molecular mechanism of urinary tract pathogenic bacterial strains and prostate cancer cells (Pc 3). Nanocomposite prepared in this examination exhibited notable structural, functional stability with nanoarchitecture which was affirmed by Fourier transform infrared spectroscopy (FTIR), electron microscopic studies, atomic force microscopy (AFM), vibrating sample magnetometric analysis (VSM) and X-ray diffraction (XRD), Synthesised Nanocomposite brought about notable antibacterial activity against urinary tract pathogenic strains by recording potential inhibitory effect on the expression of Las R gene. Inhibition of Las R gene expression reduced notable effect on biofilm development. Anticancer activity against prostate cancer cells (Pc3) was investigated by measurement of HOXB13 gene expression level. Inhibition of HOXB13 gene expression by the IONC brought about structural, functional changes. HOXB13 gene expression inhibition reveals a remarkable cytotoxic effect by recording decreased cell viability. Morphometric analysis by phase-contrast and DAPI fluorescence staining demonstrates that the Nanocomposite prompted cell morphology anomalies or apoptotic changes. Nanocomposite treatment brought about a good sign of Apoptosis by recording enhanced caspase 3 and 9 activities, DNA fragmentation and elevated reactive oxygen species generation (ROS). Hemocompatibility studies were carried out to determine the biocompatibility of the Nanocomposite. Spectrophotometric estimation of plasma haemoglobin, microscopic examination of whole blood cells shows the Nanocomposite was not inciting any indication of toxicity. These findings infer that IONC synthesised in the present study is the promising contender for a broad scope of biomedical applications, especially as an antibacterial and anticancer agent. [Display omitted] • Gum acacia-poly ethylene glycol grafted iron oxide nanocomposite with potential pharmacological effect was proposed in this study. • Nanocomposite induced molecular mechanism inhibition was studied by determination of Pseudomonas aeruginosa Las R gene expression • Inhibition of HOXB13 gene expression on the prostate cancer cell line (PC 3) known to cause marked effect on the anti cancer activity. • No sign of hemolysis on the blood cells reveals the best biocompatibility of the nanocomposite. [ABSTRACT FROM AUTHOR]

The complement system plays a key role in opsonization and immune clearance of engineered nanoparticles. Understanding the efficiency, inter-subject, and inter-strain differences of complement opsonization in preclinical species can help with translational nanomedicine development and improve our ability to model complement response in humans. Dextran-coated superparamagnetic iron oxide (SPIO) nanoparticles and a wide range of non-magnetic iron oxide nanoparticle formulations are widely used in magnetic resonance imaging and as clinically approved iron supplements. Previously we found that opsonization of SPIO nanoworms (NW) with the third complement protein (C3) proceeds mostly via the alternative pathway in humans, and via the lectin pathway in mice. Here, we studied the pathway and efficiency of opsonization of 106 nm SPIO NW with C3 in different preclinical species and commonly used laboratory strains. In sera of healthy human donors (n = 6), C3 opsonization proceeded exclusively through the alternative pathway. On the other hand, the C3 opsonization in dogs (6 breeds), rats (4 strains) and mice (5 strains) sera was either partially or completely dependent on the complement Ca2+-sensitive pathways (lectin and/or classical). Specifically, C3 opsonization in sera of Long Evans rat strain, and mouse strains widely used in nanomedicine research (BALB/c, C57BL/6 J, and A/J) was only through the Ca2+-dependent pathways. Dogs and humans had the highest between-subject variability in C3 opsonization levels, while rat and mouse sera showed the lowest between-strain variability. Furthermore, using a panel of SPIO nanoparticles of different sizes and dextran coatings, we found that the level of C3 opsonization (C3 molecules per milligram Fe) in human sera was lower than in animal sera. At the same time, there was a strong predictive value of complement opsonization in dog and rat sera; nanoparticles with higher C3 deposition in animals showed higher deposition in humans, and vice versa. Notably, the opsonization decreased with decreasing size in all sera. The studies highlight the importance of the consideration of species and strains for predicting human complement responses (opsonization) towards nanomedicines. [Display omitted] [ABSTRACT FROM AUTHOR]

Conceptual scenarios of temperature effect on property of iron oxide-graphene for synthesis of carbon nanotubes/graphene hybrid material. [Display omitted] • Reduced Fe 2 O 3 /GO was employed as catalyst for synthesizing carbon nanotubes (CNTs) via catalytic chemical vapor deposition. • When the Fe 2 O 3 /GO was employed within a temperature range of 700−900 °C, Fe 2 O 3 was reduced to α-Fe. • The α-Fe could preferably lead to CNT growth on the graphene surface. • The α-Fe was transformed to γ-Fe when the Fe 2 O 3 /GO was subject to the temperature of 1,000 °C, resulting in formation of carbon spheres. • Conceptual scenarios of CNT/graphene hybrid material formation with respect to the pretreatment and synthesis temperature were proposed. Iron oxide embedded on graphene oxide (Fe 2 O 3 /GO) was prepared by chemical exfoliation followed by wet impregnation. Reduced Fe 2 O 3 /GO could be employed as catalyst for synthesizing carbon nanotubes CNTs via catalytic chemical vapor deposition CCVD of n-hexane within a temperature range of 700-1000 °C. It was found that during the synthesis process, pretreatment affected the transformation of iron nanoparticles in the Fe 2 O 3 /GO, leading to significant difference in formation of carbon nanoparticles. When the Fe 2 O 3 /GO was employed within a temperature range of 700−900 °C, Fe 2 O 3 was reduced to α-Fe, yielding CNT growth on the graphene surface. However, the α-Fe could be transformed to γ-Fe when the Fe 2 O 3 /GO was subject to the temperature of 1000 °C, resulting in formation of carbon spheres instead of CNTs. After experimentally verified, conceptual scenarios of CNT/graphene hybrid material formation with respect to the pretreatment and synthesis temperature were proposed and discussed. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate the effect of iron oxide particle deposition on follow-up mammograms and MRI examinations of patients who underwent sentinel lymph node detection with iron oxide particles. Two hundred and eighteen patients who had sentinel lymph node biopsy (SLNB) with iron oxide particles were evaluated. Follow-up MRI and mammography were available in 36 and 69 cases respectively. MRI examinations were evaluated for ferromagnetic artifacts that were graded as follows: 0 = No artifact, 1 = Focal area, 2 = Segmental and 3 = Regional signal void artifact. Mammography artifacts were evaluated for the presence of dense particles. Pearson's chi-square test was used for statistical analyses and P < 0.05 was accepted as significant. MRI artifact grading was as follows: Grade 0: 11 (30.6%), Grade 1: 14 (38.9%), Grade 2: 3 (8.3%), and Grade 3: 8 (22.2%). The grade of artifacts differed across surgery types (P = 0.019). Grade 3 artifacts were higher in breast conserving cases whereas Grade 0 was more frequent in subcutaneous mastectomy cases. Three out of 69 (4.4%) cases who had follow-up mammography had artifacts due to iron oxide particle accumulation which presented as Grade 3 MRI artifact in all. Accumulation of iron oxide particles after SLNB with paramagnetic tracers causes artifacts on follow-up MRI examinations in half of the cases but it is significantly low in mammograms. These artifacts may be confusing in the evaluation of the images. Radiologists must be aware of these tracers and their artifacts whereas patients should be questioned for the type of SLNB before a follow-up examination. • SLNB performed with iron oxide particles may accumulate in the breast and cause troublesome artifacts in follow-up MRI examinations • Accumulating iron oxide particles that are administered in SLNB may cause artifacts in mammography mimicking malignant lesions • Breast cancer patients must be questioned for the usage of iron oxide particles in SLNB before a follow-up mammogram or MRI [ABSTRACT FROM AUTHOR]

There is a growing interest in eco-friendly and cost-effective organic-inorganic nanocomposites due to their alignment with the principles of "green" chemistry, as well as their biocompatibility and non-toxicity. This study focused on producing Chitosan-PEG-Fe 2 O 3 @NiO nanomagnetic composites to improve the stability, dielectric properties, and antimicrobial effectiveness of these nanocomposite materials. The process involved synthesizing Fe 2 O 3 @NiO via sol-gel and polymerizing chitosan-PEG. The nanocomposites were characterized by XRD, TEM, FTIR, optical, dielectric, and VSM. Incorporating Fe 2 O 3 @NiO significantly improved stability, and the interaction with Fe2O3 during the sol-gel process facilitated the formation of NiFe 2 O 4 with an increase in the crystallinity within the chitosan-PEG matrix. The study examined optical and dielectric properties, highlighting that the 3 NiO-doped chitosan-PEG-Fe 2 O 3 composites had high electrical conductivity (1.8 ∗ 10−3 S/cm) and a significant dielectric constant (106 at low frequencies). As the ratio of NiO NPs within the chitosan-PEG-Fe 2 O 3 increases, the energy band gap of chitosan-PEG-Fe 2 O 3 films decreases up to 3.7 eV. This decrease is owing to the quantum confinement effect. These composites also demonstrated improved antimicrobial activity against E. coli and S. aureus and higher activity in the presence of nanomagnetic particles. The minimum inhibitory concentrations of CS-PEG-Fe 2 O 3 /NiO NPs against (Bacillus cereus , M. luteus , S. aureus and (S. enterica , H. pylori , E. coli) were (22–35 mm) and (21–34 mm), respectively. [ABSTRACT FROM AUTHOR]

• Low content of α-Fe 2 O 3 particles, spanning a particle size range from nanometers to microns, were employed in reactions with sodium borosilicate glass. • Through experimental characterization and numerical simulation, we analyzed the effect of iron oxide particle size on the color of dispersion systems. • Compared to the batch only, less distortion happened by using the melted cullet. Smaller particle sizes of iron oxide doping at 1100 ℃ could retain the structure stability. • We systematically introduced a constitutive model of the reactive process. Fe3+ is readily reacted with structural units to modify various properties of the borosilicate glasses and glass ceramics. However, there exists some controversies on Fe 2 O 3 containing borosilicate glasses: (1) whether the Fe 2 O 3 turned into the nanometer-sized polycrystalline structure or reacted with the glass matrix to form a new substance and (2) whether the role of Fe 2 O 3 was depended on its concentration in the network of glass. Theoretical extinction spectra of α-Fe 2 O 3 particles ranging from 1 to 180 nm in borosilicate glass align with UV–vis absorption spectra. Based on the Na 2 O-B 2 O 3 -Fe 2 O 3 phase diagram , x Fe 2 O 3 ·(100- x) [41.6B 2 O 3 –20.7Na 2 O-19.2CaO-9.7Al 2 O 3 –7.0SiO 2 –0.6ZnO] (x =1.20∼1.95 mol%) were prepared for this study, analyzing from exterior characteristics to interior structure. Molecular vibrational spectroscopy and component structure measurement were applied to study the effect of doping α-Fe 2 O 3 powders (particle sizes of 30 nm, 1 μm, 75 μm) on the sodium borosilicate glasses. Combination of experimental characterization and numerical simulation were also utilized to investigate the effects of iron oxide particle size on the color of dispersion systems. We discovered that (i) doping with either nanometer-sized or micron-sized particles of α-Fe 2 O 3 can result in both the substitution for B3+ in tetra-coordination [BO 4 ] and the bonding with [BO 3 ] units within the amorphous network of sodium borosilicate glasses; (ii) Even at lower concentrations, α-Fe 2 O 3 can still act as a network intermediate, combining both its former role and modifying properties. Based on these outcomes, for the reactive process, we formulated a constitutive model which offers valuable insights into understanding the behavior of iron oxide in sodium borosilicate glass. These findings are crucial for comprehending the processes involved in matrix preparation and are pivotal for progressing to the subsequent stage where designing and fabricating nanocomposite materials based on these matrices with spatial separation. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel electrochemical sensor for dopamine detection was successfully developed. • The IL terpolymer/iron oxide/MWCNT electrode displayed a great synergistic response. • Dopamine was detected in the presence of a 25-fold excess of ascorbic acid. • After 80 runs TS-MAG-MWCNT electrode showed only an 8% reduction in its sensitivity. • Sensor response is not affected by the matrix composition or other interferents. In this study, we introduce a novel electrochemical sensor for dopamine (DA) detection utilizing an ionic liquid-based terpolymer/iron oxide/multiwalled carbon nanotube (TS-MAG-MWCNT) nanocomposite electrode. The synergistic combination of improved surface adhesion, electrocatalytic activity, and electron conductivity of each individual material enables the determination of DA in the presence of a 25-fold excess of AA (ascorbic acid). The electrode, operated by square wave voltammetry, allows the detection of DA within a wide linear working range from 1 µmol/L to 200 µmol/L, with a limit of detection of 63 nmol/L. A single TS-MAG-MWCNT electrode can be used for more than 80 consecutive runs, with only an 8 % reduction in its sensitivity. Additionally, the response of electrodes fabricated in different batches varies by only 5 %. The sensor's response is not affected by the matrix composition or other interferents, as demonstrated by experiments conducted in synthetic urine. [ABSTRACT FROM AUTHOR]

[Display omitted] • A grain-like morphology of Fe 2 O 3 was produced by the Co-precipitation method. • Mesoporous carbon composites with iron oxide nano granular with high specific surface area and porosity for antimicrobial studies. • The as-synthesized mesoporous carbon composite with iron oxide has a potential antimicrobial activity. Bacterial infections keep posing a severe hazard to human health. Investigating efficient innovative antibacterial methods is exceedingly crucial. In this instance, coprecipitation is used to produce iron oxide and mesoporous carbon-iron oxide nanostructures with surfaces that resemble grains for antibacterial treatment. More importantly, surfaces composed of iron oxide with embedded mesoporous carbon exhibit higher bacterial consistency, which is advantageous due to the efficient interaction of bacteria with nanostructures. In antibacterial studies, nanostructures are shown to have an all-encompassing combinatorial antibacterial action against Gram-positive Bacillus cereus (B. cereus), and Staphylococcus aureus (S. aureus), and Gram-negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). In the current study, a simple method to produce antibacterial agents for antibacterial applications is presented. This method involves constructing a combined formulation and morphological structure. In the successful prevention and cure of bacterial infections, iron oxide with a small quantity of mesoporous carbon has a lot of potential. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel PAA/PVP/Fe 2 O 3 @DOX delivery platform was synthesized via double emulsion method. • Fe 2 O 3 strongly increased drug loading (48.5%) and encapsulation efficiency (86.6%). • Sustained and selective DOX release in acidic conditions (54 % in 24 h) was found. • It showed increased toxicity to cancer cells than free Dox due to ROS induced by Fe 2 O 3. • The designed pH-responsive platform shows great potential for breast cancer therapy. Recently, stimuli-responsive drug delivery systems (DDS), especially pH-responsive ones, have drawn a lot of attention to overcome the unfavourable side effects of traditional cancer treatments. In this work, a nanocomposite hydrogel based on polyacrylic acid (PAA), polyvinylpyrrolidone (PVP), and iron oxide (hematite, Fe 2 O 3) nanoparticles was developed using the water/oil/water emulsification technique for the efficient delivery of doxorubicin (DOX) drug. The synthesized nanocarrier was characterized via XRD, and FT-IR to get information about its crystalline structure and the interaction between the functional groups of the different constituents, respectively. Its size distribution and colloidal stability were investigated via DLS and zeta potential tests, and morphological study was carried out by FE-SEM. The nanoparticles were found to be uniform and monodisperse, with an average size of 319 nm and a surface charge of −30.4 mV. The incorporation of hematite increased the drug loading (48.5 %) and encapsulation efficiency (86.57 %) due to its high porosity and surface area. Drug release was tested at pH 7.4 and 5.4, corresponding to healthy and cancerous tissues, and the results demonstrated the pH responsiveness of the system, with faster release (54 % in 24 h) in the acid medium. MTT and flow cytometry tests corroborated its strong anticancer effect since the nano-platform significantly reduced the survival rate of cancer cells. The designed pH-responsive platform holds great potential for breast cancer therapy. [ABSTRACT FROM AUTHOR]

Hematite is an iron oxide commonly found in terrestrial environments and plays an essential role in controlling the migration of heavy metal(loid)s in groundwater and sediments. Although defects were shown to exist both in naturally occurring and laboratory-synthesized hematite, their influences on the immobilization of heavy metal(loid)s remain poorly understood. In this study, hematite samples with tunable vacancy defect concentrations were synthesized to evaluate their adsorption capacities for the cation Pb(II) and for the oxyanion As(V). The defects in hematite were characterized using XRD, TEM-EDS mapping, position annihilation lifetime spectroscopy, and XAS. The surface charge characteristics in defective hematite were investigated using zeta potential measurements. We found that Fe vacancies were the primary defect type in the hematite structure. Batch experiments confirmed that Fe vacancies in hematite promoted As(V) adsorption, while they decreased Pb(II) adsorption. The reason for the opposite effects of Fe vacancies on Pb(II) and As(V) immobilization was investigated using DFT calculations and EXAFS analysis. The results revealed that Fe vacancies altered As–Fe coordination from a monodentate to a bidentate complex and increased the length of the Pb–Fe bond on the hematite surface, thereby leading to an increase in As(V) bonding strength, while decreasing Pb(II) adsorption affinity. In addition, the zeta potential analysis demonstrated that the presence of Fe vacancies led to an increase in the isoelectric point (IEP) of hematite samples, which therefore decreased the attraction for the cation Pb(II) and increased the attraction for the oxyanion As(V). The combination of these two effects caused by defects contributed to the contrasting difference between cation Pb(II) and oxyanion As(V) immobilization by defective hematite. Our study therefore provides new insights into the migration and fate of toxic heavy metal(loid)s controlled by iron minerals. [Display omitted] • Hematite with tunable vacancy defects were obtained by ball-milling treatment of well-crystallized hematite. • Fe vacancies were the primary defect type existing in the defective hematite samples. • Increasing Fe vacancy defects led to an increase in oxyanion As(V) adsorption on hematite. • Fe vacancies was detrimental to the immobilization of cation Pb(II) on hematite. • Fe vacancies altered affinity of hematite to As(V) and Pb(II) due to the change of coordination environments. [ABSTRACT FROM AUTHOR]