Search

Hydrogen peroxide (H 2 O 2) is a vital messenger molecule facilitating signal transmission within cellular systems. The accurate quantification of H 2 O 2 in complex environments, such as human serum, is instrumental in elucidating its diverse biological functions. In this study, we present the development of a robust electrode platform by integrating hemoglobin onto iron oxide (Fe 3 O 4) nanoparticles and reduced graphene oxide (rGO) as a conducting support for the sensitive detection of H 2 O 2 in human serum. The Fe 3 O 4 /rGO nanocomposite was synthesized via a facile single-step thermolysis reaction in the presence of oleylamine. Transmission electron microscopy (TEM) analysis revealed the formation of highly monodisperse Fe 3 O 4 nanoparticles that were uniformly dispersed over the reduced graphene surface. The rGO surface provided abundant active sites (Fe 3 O 4) for H 2 O 2 sensing. Consequently, the resulting Hb/Fe 3 O 4 @rGO modified electrode exhibited a wide linear range of H 2 O 2 concentrations from 1.5 to 2684 µM, demonstrating high sensitivity and low detection limit. Further characterization of the Hb/Fe 3 O 4 @rGO/GC electrode revealed a high surface coverage (τ = 3.0 × 10−9 mol cm−2), charge transfer coefficient (α = 0.83), and electron transfer rate constant (k s = 1.33 s−1). Subsequently, the Hb/Fe 3 O 4 @rGO/GC sensor probe was employed to analyze H 2 O 2 in real human serum samples, demonstrating excellent recovery rates ranging from 99.8 % to 104.0 %. The nanocomposite material, designed through the innovative combination of graphene oxide reduction, Fe 3 O 4 nanoparticle decoration, and oleylamine amide/amine bonding, serves as an excellent electrode material for H 2 O 2 concentration sensing. Thus, this study presents a promising platform for the future determination of H 2 O 2 biomarkers in clinical settings. [Display omitted] [ABSTRACT FROM AUTHOR]

The influence of the combination of sludge load control and iron oxide (IO) addition strategies on food waste anaerobic digestion (AD) was explored. The results showed that low sludge loads or IO addition could significantly enhance AD performance. Low sludge loads promoted substrate hydrolysis and volatile fatty acids degradation, which enhanced the biochemical methane potential (BMP) and production rate, respectively. IO addition promoted the CH 4 yield and maximum CH 4 production rate (R m) by 65.50% and 206.79%, respectively, by promoting hydrolysis and interspecies electron transfer among syntrophic microbes. Moreover, although the presence of IO could prevent the failure of AD in extremely high sludge load conditions, it could not ensure complete BMP recovery. In an IO-assisted reactor, low sludge loads decreased the methanogenic lag phase by 53.15% and increased the BMP and R m by 49.93% and 120.11%, respectively. Although adequate IO dosage could effectively improve the digester performance, excessive dosage may limit the economic benefits. Overall, the AD performance could be optimized by simultaneously controlling the sludge load and IO addition. [ABSTRACT FROM AUTHOR]

• Iron oxide nanoparticles recovered from the acid mine drainage treatment are suitable to produce nanofluids. • Iron oxide nanoparticles in concentration 0.10–0.75 wt% can be used to produce stable nanofluids. • Additional 7–10% oil recovery is achieved after flooding due to injection of iron oxide-based nanofluids. Oil is one of the most intensively used energy sources in the world and, as a fossil fuel, it is a finite resource. Different methods have been explored to increase oil recovery from mature fields, particularly using enhanced oil recovery (EOR) with the help of nanofluids. This study performed EOR tests using iron oxide nanoparticles added to brine and sodium dodecyl sulfate solutions. Three types of iron oxide nanoparticles were examined: commercial (IO), derived from the acid drainage of an underground coal mine (SIO), and temperature-sensitive functionalized (TSIO). The nanoparticles were well characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, high-resolution X-ray photoelectron spectroscopy, and transmission electron microscopy. The nanofluids were evaluated through dynamic light scattering measurements and determination of the viscosity, turbidity, contact angle and surface tension. There was not significant variation in the surface tension of the samples, which ranged between 25.46 and 28.28 mN m−1. However, the contact angle exhibited notable fluctuations depending on the nanoparticles concentration, ranging from 7.39° to 24.43°. Furthermore, the zeta potential suggests that the stability of the nanofluid samples falls within the moderate to medium range. An improvement in oil recovery reached 10% with the commercial nanoparticles (0.50 wt%), followed by 8.5% using the synthesized (0.25 wt%) and 7.5% using the functionalized (0.25 wt%). Moreover, all nanofluids showed good stability for up to 30 days, and their viscosity showed a direct relationship with the enhancement in oil recovery. [ABSTRACT FROM AUTHOR]

Spray pyrolysis at various temperatures was employed to produce non-crystalline and crystalline iron oxide (α-Fe 2 O 3) thin films on glass. The amorphous and crystalline characteristics of α-Fe 2 O 3 thin films were affirmed via X-ray diffraction analysis. With low deposition times (5 min) and at various substrate temperatures, iron oxide seems almost in a non-crystalline structure. As for the increase in deposition time (40 min), the crystallinity's degree was enhanced. According to Tauc's law, the direct gap energy E d for both the amorphous and the crystalline phases, were found to be 1.95 and 2.125 eV, respectively. Moreover, the indirect gap energy, E in = 1.65 and 1.71 eV were obtained for the amorphous phases and the crystalline phases, respectively. The linear and non-linear optical features of amorphous and crystalline structure were meticulously and adaptably detailed. It is observed that the behavior of the refractive index n (λ) and extinction coefficient k (λ) of the crystalline state was lower than that of the amorphous state. The real and imaginary linear dielectric constant and also the thin film quality factor were estimated for both the amorphous and crystalline states as well as the volume and surface energy loss functions for the crystalline and amorphous states. In conclusion, amorphous and crystalline α-Fe 2 O 3 nanocrystalline films improved their optical properties, making them potential candidates for multifunctional applications such as optoelectronics and spintronics electronics devices. [ABSTRACT FROM AUTHOR]

• Experiments are performed in both CSS and MSS at different water depths in coated and uncoated absorber. • Increase in water depth decreases the fresh water generation from both cases. • The fresh water produced from CSS and MSS are 3.85 and 6.03 kg/m2 respectively. • The thermal and exergy efficiencies are found as 47.67 and 4.53 % respectively using the MSS. • CPL of fresh water produced is lowered by 29.96 % than the SS using uncoated absorber. The quantity of drinkable water that is easily accessible is dwindling at an extremely quick pace. An extra degree of complication has been added to the problem as a consequence of the depletion of freshwater resources brought on by human activities. The primary objective of the present study is to enhance the rate of fresh water generation through the low-cost solar desalination unit using iron oxide as coating material using different thickness of water placed in the absorber plate. The experimental results revealed that the influence of metal oxide nanoparticle as absorber coating material improved the rate of fresh water generation by 36.08 % than the conventional solar still at a minimum thickness of water as 1 cm in the absorber. The palatable fresh water generated from the SS without any absorber coating for the thickness of water as 10, 20 and 30 mm is found to be 3.85, 3.09 and 2.90 kg/m2 respectively. However, with effective coating of the absorber plate using Fe 2 O 3 nanoparticle, the cumulative daily palatable water generated from the solar still for different thickness of water as 10, 20 and 30 mm is enhanced to about 6.03, 5.36 and 4.72 kg/m2 respectively. There is a significant enhancement of about 38.47 to 60.15 % and 1.96 to 4.53 % in the daily energy, and exergy efficiencies of the solar still using coated absorber plate in the SS respectively while compared to the SS using uncoated absorber at the lowest thickness of water in the absorber of basin. Similarly, the CPL of fresh water produced from the SS using coated absorber is lowered by 29.96 % than the SS using uncoated absorber. [Display omitted] [ABSTRACT FROM AUTHOR]

Drinking of water polluted with heavy metals is a means by which heavy metals bio accumulate in the human body. The rise in galamsey (illegal mining) activities in Ghana has resulted in heavy metal pollution in most water bodies in the country. Above the permissible limits, these metals cause health issues such as cancer, brain damage, kidney damage and other respiratory diseases. Hence, a smart solution to this menace is urgently needed. In this study, iron oxides were recovered from cupola furnace slag by magnetic separation and froth flotation. The recovered iron oxide was modified using electrospinning with the aid of polyvinyl alcohol after which it was calcined and used as adsorbent to detoxify lead and arsenic from two galamsey polluted water bodies in Obuasi, Ghana. Samples of the adsorbent were characterized using X-ray Fluorescence (XRF), X-ray Diffractometry (XRD), Fourier Transform Infrared Spectrometry (FTIR), Scanning Electron Microscopy (SEM) and Brunauer-Emmer-Teller (BET) method. The highest recovery for iron oxide using magnetic separation was 99.42% and that of froth flotation was 90.64%. The recovered iron oxide used as adsorbent was composed 53.04% iron oxide, with major phases like magnetite, hematite, goethite and quartz. Moreover, the surface functional group were determined to be Fe–O and OH. Also, the calcined nano fibres which were spherical in shape with rough surfaces had a specific surface area of 1.1331 m2/g. The contaminated and detoxified water were also analyzed using Atomic absorption Spectroscopy (AAS). Both adsorbent (beneficiated iron oxide and calcined nano fibre) performed well in the adsorption process, with the recovered iron oxide having 97.33% maximum lead removal efficiency while an 81.00% maximum removal efficiency for arsenic. The calcined nano fibre had a maximum of 99.99% removal efficiency for lead and 88.40% maximum efficiency for arsenic. Additionally, the adsorption fits the Langmuirian isotherm model better than the Freundlich model, indicating mono layer coverage. • Cupola furnace slags are rich in iron oxides and can be recovered for various application. • Magnetic separation and froth flotation were used to recover the iron oxides from the cupola furnace slag. • The recovered iron oxides (Fe 3 O 4 , α -Fe 2 O 3 , FeO 2 H and γ -Fe 2 O 3) were used for lead and arsenic adsorption. • The iron oxides achieved high removal efficiency for the heavy metals (Pb and As). [ABSTRACT FROM AUTHOR]

[Display omitted] • Pigment adsorption onto iron oxides is mainly due to electrostatic attraction. • The pigment-binding capacity is in the order of ferrihydrite > goethite > hematite. • The affinity of iron oxide towards pigment is in the sequence of AR > TA > BB. • Different mechanisms involved in pigment adsorption vary with pH values. • Pigments and Cu2+ have a mutual promotion effect on their adsorption. The knowledge about the adsorption properties of pigments onto different iron oxide minerals is still limited. The adsorption behaviors of three typical pigments, including amaranth (AR), tartrazine (TA), and brilliant blue (BB), onto three iron oxides (ferrihydrite, goethite, and hematite) were investigated. The primary mechanism of their interactions was the electrostatic attraction. The affinities of iron oxides toward any pigment were generally in the sequence of ferrihydrite > goethite > hematite (e.g., the maximum adsorption amounts (q max) of AR onto the three iron oxides were 35.5 mg/g, 11.6 mg/g, and 4.2 mg/g, respectively), which was related to the differences in physicochemical properties of minerals (e.g., specific surface area, surface hydroxyl density, and crystal structure). Interestingly, for a given iron oxide, the pigment-binding capacity of the mineral was in the order of AR > TA > BB. This effect was attributed to variations in pigment molecular sizes and electrostatic interactions between pigments and minerals. The pigment-binding capabilities of iron oxides changed as the solution pH varied. Hydrogen-bonding and electrostatic interactions were the main mechanisms below and above pH > pH PZC (pH value at zero point charge), respectively. Furthermore, adding Cu2+ facilitated pigment adsorption, mainly stemming from the surface-bridging effect. Pigments also enhanced Cu2+ adsorption onto iron oxides due to the decreasing electrostatic repulsion between Cu2+ and particles as well as the complexion between Cu2+ with pigment molecules adsorbed on mineral surfaces. The insightful information demonstrates that ubiquitous iron oxide minerals can affect the fate of pigments in natural environments. [ABSTRACT FROM AUTHOR]

Liquid lead–bismuth eutectic (LBE) is a heavy metal alloy with great potential as a coolant and spallation target material for Generation IV nuclear reactors. For LBE technology to be widely accepted as reliable, a comprehensive understanding of LBE coolant chemistry is crucial. Specifically, precise determination of chemical interactions between corrosion products and dissolved oxygen in LBE is essential. For that purpose, the thermal cycling method is used in the present research, in which a well-controlled batch of LBE is repeatedly cooled while a potentiometric oxygen sensor monitors the dissolved oxygen concentration. According to the literature, magnetite ( Fe 3 O 4 ) is confirmed to be an important oxide to describe oxygen–iron interaction in LBE. However, thermal cycling experiments indicate the presence of another oxide, besides Fe 3 O 4 , participating in LBE bulk chemistry under conditions relevant for LBE-cooled reactors (200 °C–400 °C, 1 0 − 8 wt.%– 1 0 − 5 wt.% dissolved oxygen concentration). By varying iron impurity content, nickel impurity content and cooling rate in the experiments, the oxide has been identified as hematite ( Fe 2 O 3 ). Thermodynamic equilibrium calculations show that Fe 2 O 3 formation through the reaction of Fe 3 O 4 with dissolved oxygen can explain the observed oxygen trends. As Fe 2 O 3 could form during LBE cooling, an oxygen control strategy should take into account additional oxygen consumption in the reactor cold leg. [Display omitted] • As-received liquid lead–bismuth eutectic is studied by cycling temperature. • Electrochemical oxygen sensor measures the dissolved oxygen concentration in-situ. • A new oxide is found in the bulk near the oxygen saturation limit at 200 – 400 ° C. • Addition of nickel and iron reveals the oxide is hematite forming from magnetite. • A correlation is derived to calculate the oxide's equilibrium from JANAF database. [ABSTRACT FROM AUTHOR]

Atomic-scale wear, behaving distinctly from macroscale wear, has been gaining significant scientific interest. We previously proposed a semi-empirical wear model for covalent bonding materials, which primarily describes an interfacial-bond-dominant atomic-scale wear process. To assess the model's broader applicability on other material types, herein we selected the iron oxide (Fe 2 O 3) as a representative ionic bonding material and conducted the large-scale atomistic simulations. The simulations unveiled two main atomic-scale wear mechanisms of Fe 2 O 3 : plastic deformation/cracking of nano-asperities induced by the asperity collision, and atom-by-atom attrition caused by the interfacial O–Fe bond formation. Crucially, our simulations proved effective in capturing the atom-by-atom attrition wear, thus confirming its validity for ionic materials and expanding its potential usefulness to a broader range of materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Spray solution combustion synthesis is proposed as a onestep method for preparation of nanostructured iron oxide–silver patchy particles for polyfunctional applications. [ABSTRACT FROM AUTHOR]

Li-rich layered cathode materials have received wide attention due to their superior Li-storage capability. However, their applications are still limited by capacity degradation and voltage decay, which is caused by the phase transition and metal dissolution during repeated cycling. In this work, iron oxide (FeO x) atomic layer deposition (ALD) was performed on Li-rich layered cathode powders in a fluidized bed reactor, followed by an annealing process to further improve their electrochemical performance. After 100 cycles of charge-discharge at 55 °C and 1C (1C = 250 mA g−1), the cathode made from particles with 40 cycles of FeO x ALD and annealing showed a 73% retention of the initial capacity (221 mAh g−1), while the electrode made from the pristine powders showed only 26% retention of the initial capacity (197 mAh g−1) at the same conditions. The enhancement of Li+ transport and cyclic stability stemmed from a stable Fe-doped spinel phase on the surface of cathode particles after ALD coating followed by annealing. A detailed post-test analysis demonstrated that the modification limited impedance growth and suppressed electrolyte degradation and metal dissolution. Image 1 • Combining ALD and annealing resulted in Fe subsurface-doping in LRNMC particles. • The Fe-doped spinel phase improved surface stability and suppressed side reactions. • The Li+ transport was improved by surface modification, resulting in a higher capacity. [ABSTRACT FROM AUTHOR]

• Iron oxide with variable quantities of Feδ+ and SO 4 2− mediated by temperatures of SO 2 mixed with O 2. • Iron oxide with surface Feδ+ (δ ≤ 2) functioning as H 2 O 2 activators to form aqueous OH. • Iron oxide with SO 4 2− functionalities converted to surface SO 4 •- via radical transfer from aqueous OH. • Iron oxide with SO 4 − species used to degrade aqueous pollutants via heterogeneous catalysis. • Iron oxide with SO 4 − species acting as recyclable crackers of aqueous contaminants. OH or SO 4 − are powerful oxidants that efficiently degrade recalcitrant contaminants. The productions of OH and SO 4 − via activation of their precursors (H 2 O 2 and Na 2 S 2 O 8), however, can be sustainable only after continuously feeding such precursors into the activators. Motivated by the advantages of SO 4 − over OH as an environmental cracker, this study highlighted a simple and proficient way to persist solid-supported SO 4 − species used to accelerate the decomposition of recalcitrants in the presence of an electric potential. While using ubiquiotous iron oxide as a platform to accomodate SO 4 −, we functionalized iron oxide surface with SO 4 2- species, which could be transformed into surface SO 4 − species via radical transfer from aqueous OH species. Specifically, a series of SO 4 2--modified iron oxide catalysts were synthesized using SO 2 and O 2 at 300–600 °C in order to vary their surface properties such as the contents of surface Fe δ+ species acting as H 2 O 2 activators to form OH, the contents of surface SO 4 2- species functioning as surface SO 4 − precursor, and the character of S O bonds innate to SO 4 2- functionalities linked to their long-term stability. In addition to the comparison of energetics between SO 4 2- functionalities and their SO 4 - analogues via computation, a kinetic assessment of reaction runs were conducted under controlled environments to gather convincing evidence that the formation of surface SO 4 − via its radical interconversion with aqueous OH was highly plausible and that surface SO 4 − would be the major decomposer of phenol (model compound of recalcitrants). In addition, 500 °C was found to be the optimized temperature to greatly populate Fe δ+ and SO 4 2- species rigidly immobilized on iron oxide surface among all temperatures studied, thereby providing the greatest activity and recyclability to degrade phenol. [ABSTRACT FROM AUTHOR]

• Iron oxide doped carbon nitride was synthesized. • Doped photocatalyst was proven better than pure carbon nitride. • Photon concentrator was fabricated by 3D printing. • Dicamba was degraded by photocatalyst/H2O2 exposure under visible light. We have synthesized iron oxide doped carbon nitride with 0.5 to 2 wt.% iron oxide and characterized by XPS, TGA, FTIR, SEM, photoluminescence spectroscopy and photoelectrochemical measurements. A herbicide, dicamba was employed as model organic pollutant for degradation in presence with the catalyst and hydrogen peroxide. A 3D printed photon concentrator with two chips on board (COB) LEDs with visible light spectra and two complex parabolic mirror surfaces was used as photo-reactor. The findings revealed that both photocurrent and degradation of dicamba were functions of light intensity and concentrator geometry. The rapid degradation of dicamba can be attributed to the holistic and individual actions of structural components of the photocatalyst. Four distinct phenomena, including photocatalytic activity of carbon nitride, quenching of electron/hole pairs and generation of additional reactive hydroxyl radicals by hydrogen peroxide, Fenton and photo-Fenton activity of iron oxide component of carbon nitride in presence of hydrogen peroxide and photocatalytic activity of iron oxide alone in conjuncture with carbon nitride can contribute to the overall photocatalytic activity of the system. Liquid Chromatography-Mass spectrometry (LCMS) analysis of the degradation products showed loss of chlorine from the aromatic ring and evidence of free radical addition reactions in the course of photocatalysis. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 nanoparticles (NPs) coated by the SiO 2 shell with a thickness up to ˜6.5 nm were synthesized by a fast and facile microwave irradiation approach. The thickness of the SiO 2 shell around Fe 2 O 3 NPs could be controlled by varying tetraethoxysilane (TEOS) concentration as well as avoiding individual SiO 2 particle formation. The synthesized Fe 2 O 3 @SiO 2 core-shell nanocomposites (NCs) were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) spectroscopy. The bigger particle size compared to the uncoated Fe 2 O 3 NPs and Si O Si asymmetric stretching vibrational band at 1101 cm−1 in the prepared NCs obtained by FE-SEM and FT-IR study, respectively anticipated the successful SiO 2 coating on Fe 2 O 3 NPs. The presence of homogeneous silica layer was authenticated by TEM observation. The change in binding energy of Fe 2p3 and Si 2p in the synthesized NCs compared to the uncoated Fe 2 O 3 and pure SiO 2 NPs corroborated the formation of Fe O Si bond at the interface of Fe 2 O 3 (core) and SiO 2 (shell). The existence of magnetic property in the prepared NCs, even above the Curie temperature of Fe 2 O 3 , was assured by vibrating sample magnetometer (VSM) study. This observation will undoubtedly inspire to design and fabricate novel heterostructures of iron oxide to retain its magnetization at high temperature. [ABSTRACT FROM AUTHOR]

A magnetic adsorbent namely magnetic iron oxide encrusted hydrocalumite-chitosan (Fe 3 O 4 @HCCS) composite was prepared by the fabrication of magnetic iron oxide (Fe 3 O 4) particles on hydrocalumite-chitosan (HCCS) composite for fluoride sorption studies in batch mode. The prepared magnetic Fe 3 O 4 @HCCS composite possesses an enhanced defluoridation capacity (DC) of 6.8 mg/g compared to hydrocalumite (HC) which possesses the DC of 2.4 mg/g. The various physico-chemical parameters such as contact time, pH, co-existing anions, initial fluoride concentration and temperature were optimized for the maximum fluoride removal. The structural changes of the sorbent, before and after fluoride sorption were studied using FTIR and SEM with EDAX techniques. The equilibrium data was well modeled by Freundlich and Langmuir isotherms. The thermodynamic parameters revealed the feasibility, spontaneity and endothermic nature of fluoride sorption. The field performance and efficiency of Fe 3 O 4 @HCCS composite was examined with the waste-water sample collected from a fluoride endemic area of Dindigul district, Tamilnadu, India using standard protocols. [ABSTRACT FROM AUTHOR]

In this research, Fe 3 O 4 particles were magnetically manipulated to create porous scaffolds using a tri-axial nested Helmholtz coils-based freeze-casting setup. This novel setup allowed for a uniform magnetic field to be applied in any direction and for it to effectively change directions at any time. Applying a uniform low magnetic field of 7.8 mT in various directions was investigated to fabricate a variety of tailored microstructures and mechanical properties in the resultant scaffolds. It was observed that using the magnetic field aligned up to 81% of the lamellar walls and also altered the area and shape of the pores of the resultant scaffolds. This lamellar wall alignment occurred at every applied magnetic field direction due to the Fe 3 O 4 particles aligning during the freeze-casting process. As a result of this alignment, increases in the mechanical properties of up to 4.1× were observed. The results provide a novel experimental technique for the fabrication of user-defined microstructures in Fe 3 O 4 -based freeze-cast materials that provides significant advantages over previous experimental setups for magnetic freeze casting. Image 1 [ABSTRACT FROM AUTHOR]

Iron oxide (Fe 2 O 3) thin films have been prepared starting from iron chloride (FeCl 3) precursor by spray pyrolytic decomposition of FeCl 3 on an ordinary glass substrate at 450 °C. The precursor concentration (C) has been varied from 0.06 to 0.3 mol l−1 keeping the other deposition parameters fixed. The (C) effect on the structural, optical and electrical properties has been studied. The XRD analysis shows that Fe 2 O 3 thin film has a rhomboedric structure with (104) plane as preferential orientation. A degradation of crystallinity followed by a change in plan orientation from (104) to (110) has been observed, when (C) has been raised to 0.2 mol.l−1.The optical transmittance spectrum shows that T(λ) decreases at higher precursor concentration. Optical band gaps w decreased from 2.21 to 2.08 eV for direct transition and from 2.03 to 1.99 eV for indirect transition when (C) increases from 0.06 to 0.3 mol l−1. The extinction coefficient (k) and refractive index (n) were also has been estimated and studied. The films deposited with C = 0.14 mol l−1 has shown the maximum mobility of 62 cm2 V−1.s−1 at room temperature. All physical properties of Fe 2 O 3 thin films investigated in this work were strongly dependent upon the precursor concentration. The obtained results provide valuable information about structural, optical, photoluminescence and electrical properties of sprayed Fe 2 O 3 , which is a very helpful issue for better understanding and perfection of the semiconductor quality for the optoelectronic application. • Iron oxide thin films were grown successfully on glass substrate by chemical spray pyrolysis technique. • Precursor concentration effects were investigated. • Structural, optical and electrical properties were studied. [ABSTRACT FROM AUTHOR]

Abstract Naphthols are industrial contaminants occurring widely in soils and waters. Remediation of organic pollutants can be done by chemical oxidation using persulfate. However, most research experiments testing degradation of organic pollutants have been done in ideal conditions, e.g. using a pure compound in pure water, and thus are weakly representative of real natural conditions where pollutants occur in complex mixtures of numerous organic compounds. Therefore we tested here the effect of the presence of small organic acids, as typical compounds occurring in natural media, on the degradation of 1-napthol with persulfate and iron oxides. Results show that organic acids decreased naphthol transformation by 3.7% for malic acid, 53.2% for tartaric acid, 72.3% for citric acid and 77% for oxalic acids, in a magnetite/persulfate system during 10 h. Meanwhile, the dissolved Fe species increased gradually with the reaction time; the highest concentration of Fe ions reached to ∼18 μM L−1 in aqueous phase. Electron paramagnetic resonance technique was applied to determine reactive oxygen species (ROS). The spin density of ·OH, detected as the main ROS, decreased initially, followed by gradually increase, suggesting that organic acids might inhibit the degradation of 1-naphthol by competing with ·OH. These findings disclose the high inhibition of the transformation by organic acids, and thus, more generally, imply that studies using only pure contaminants are weakly representative for remediation of real, natural samples. Graphical abstract Image 1 Highlights • LMWOAs exhibit inhibitory effect on 1-naphthol degradation in iron oxide/PS systems • Both of LMWOA molecular structure and iron oxide type affect 1-naphthol degradation • LMWOAs inhibit the heterogeneous activation via competition sorption on Fe surface • LMWOAs can dissolve iron oxides ions and improve the homogeneous activation of PS [ABSTRACT FROM AUTHOR]

Design of a multifunctional magnetic bionanosystem has become increasingly important towards advancing the future of clinical medicine. While hollow iron oxide nanoparticles with enhanced surface areas allow for more drug molecules to be attached to the particles, their relatively low saturation magnetization (M S) hinders their practicality in medicinal applications such as drug delivery and hyperthermia therapy. We demonstrate that this limitation can be overcome by utilizing 1D magnetic nanotubes that possess both enhanced surface areas and high M S. In this study, highly crystalline, tunable aspect ratio Fe 3 O 4 nanotubes have been successfully synthesized using a hydrothermal method. Magnetic measurements showed a clear Verwey transition (∼120 K) and high M S (∼75 emu/g) at 300 K, confirming the high quality of the synthesized Fe 3 O 4 nanotubes. Calorimetric experiments on randomly dispersed Fe 3 O 4 nanotubes in water with concentration of 1 mg/mL showed a large Specific Absorption Rate (SAR) value of 400 W/g for an AC magnetic field of 800 Oe, which increased to 500 W/g when the nanotubes were aligned parallel to the DC magnetic field and suspended in a 2% agar solution. Our study shows the possibility of using the Fe 3 O 4 nanotubes as a highly effective multifunctional nanoscale tool for targeted hyperthermia and on-demand drug delivery. • Hydrothermal synthesis of highly crystalline, tunable aspect ratio Fe 3 O 4 nanotubes. • Systematic study of the growth mechanism of the nanotubes. • The presence of Verwey transition and high M S (75 emu/g) at 300 K. • Nanotubes exhibited large SAR value compared to their hollow counterparts. • Dual-purpose applications in hyperthermia and on-demand drug delivery. [ABSTRACT FROM AUTHOR]

Highlights • Fe 2 O 3 /CNF was synthesized by electrospinning coupled with hydrothermal method. • 1D and porous Fe 2 O 3 /CNF has good conductivity and specific electrocatalytic activity. • The DSSCs with Fe 2 O 3 /CNF-based CEs achieved a PCE of 7.48%. Abstract The exploration of low-cost and efficient counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) is of great significance in view of potential application of DSSCs. Herein, the Fe 2 O 3 /CNFs composites are synthesized by electrospin method and a facile hydrothermal method, and the composites of Fe 2 O 3 /CNFs is used as a low-cost counter electrode for DSSCs. Scanning electron microscopy measurement shows that Fe 2 O 3 nanoparticles have been evenly located on the exterior of CNFs, providing abundant catalytic active sites for triiodide reduction. The one dimensional CNFs has a high conductivity, which could effectively reduce the agglomeration of Fe 2 O 3 nanoparticles, thus increasing the specific surface area of the material and facilitating the rapid transmission of ions and electrons in the electrolyte. The synergistic effect of Fe 2 O 3 /CNFs composite leads to high electrocatalytic activity. Consequently, DSSCs devices constructed with an Fe 2 O 3 /CNFs composite based on CE afford a decent power conversion efficiency of 7.48%, higher than the expensive Pt CE based DSSCs (6.97%). [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 present study investigates the running-in behaviour of low alloyed C-steel tubings in NaCl brine under CO 2 corrosive environment. These corrosion conditions are those typically found in the oil industry. The corrosion of C-steel in CO 2 environment leads to the formation of an iron carbonate scale. This scale determines the frictional behaviour at the interface between tubing and coupling. However, the tubing surface can contain iron oxides, either as a consequence of the production process or due to the presence of O 2 in the environment. The role of iron oxides is addressed by investigating the running-in behaviour of tubings with and without oxide scale present, while the influence of iron carbonates is addressed by performing additional tests in distilled water under N 2 environment. The results show that the interaction between iron oxides and carbonates determines the running-in behaviour of the tubings. The presence of iron oxides impairs the lubricious properties of the iron carbonate scale. This causes an increase in shear stresses at the sliding interface, as evidenced by the severe plastic deformation of the substrate. As a consequence, the presence of iron oxides during running-in leads to a transition from mild to severe wear. • Presence of iron oxides leads to running-in with high friction and severe wear. • Iron oxides form a MML during running in. • Low friction requires formation of an iron carbonate layer. • The inhibition of iron carbonate formation leads to a factor 2 higher friction. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Hematite (α -Fe 2 O 3) is one of the most widely studied materials for the application of water oxidation in the field of renewable energy. In order to push hematite toward maximal efficiency, a better understanding of the intrinsic limitations is essential. In this review, we cover our latest results on identifying and finding ways to overcome bottlenecks by modelling the electrochemical processes in hematite at three regimes: 1. at the bulk, the calculated hole effective mass is unfavorably high and conductivity can be improved through doping and alloying, 2. at the surface, catalysis is slow and involves long-lived surface states, but the catalytic overpotential can be reduced by adding a doping gradient or overlayers without strain, and 3. at the back contact the losses can be improved by selecting a proper metal contact. We provide unique analysis approaches that reveal fundamental understanding of electrochemistry with hematite. These models have made an impact on understanding experimental observations and have influenced subsequent theoretical investigations. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Despite the advances in molecularly targeted therapies, delivery across the blood-brain barrier (BBB) and the targeting of brain tumors remains a challenge. Like brain, bone is a common site of metastasis and requires therapies capable of discerning the tumor from its healthy cellular milieu. To tackle these challenges, we made a variation on the previously proposed concept of the earthicle and fabricated an aqueous, surfactant-free ferrofluid containing superparamagnetic iron oxide nanoparticles (SPIONs) coated with silicate mesolayers and carbon shells, having 13 nm in size on average. Nanoparticles were synthesized hydrothermally and characterized using a range of spectroscopic, diffractometric, hydrodynamic and electron microscopy techniques. The double coating on SPIONs affected a number of physicochemical and biological properties, including colloidal stability and cancer targeting efficacy. Nanoparticles decreased the viability of glioblastoma and osteosarcoma cells and tumors more than that of their primary and non-transformed analogues. They showed a greater preference for cancer cells because of a higher rate of uptake by these cells and a pronounced adherence to cancer cell membrane. Even in an ultralow alternate magnetic field, nanoparticles generated sufficient heat to cause tumor death. Nanoparticles in MDCK-MDR1 BBB model caused mislocalization of claudin-1 at the tight junctions, underexpression of ZO-1 and no effect on occludin-1 and transepithelial resistance. Nanoparticles were detected in the basolateral compartments and examination of LAMP1 demonstrated that nanoparticles escaped the lysosome, traversed the BBB transcellularly and localized to the optic lobes of the third instar larval brains of Drosophila melanogaster. The passage was noninvasive and caused no adverse systemic effects to the animals. In conclusion, these nanoparticulate ferrofluids preferentially bind to cancer cells and, hence, exhibit a greater toxicity in these cells compared to the primary cells. They are also effective against solid tumors in vitro , can cross the BBB in Drosophila, and are nontoxic based on the developmental studies of flies raised in ferrofluid-infused media. Statement of Significance We demonstrate that a novel, hydrothermally synthesized composite nanoparticle-based ferrofluid is effective in reducing the viability of osteosarcoma and glioblastoma cells in vitro , while having minimal effects on primary cell lines. In 3D tumor spheroids, nanoparticles greatly reduced the metastatic migration of cancer cells, while the tumor viability was reduced compared to the control group by applying magnetic hyperthermia to nanoparticle-treated spheroids. Both in vitro and in vivo models of the blood-brain barrier evidence the ability of nanoparticles to cross the barrier and localize to the brain tissue. These composite nanoparticles show great promise as an anticancer biomaterial for the treatment of different types of cancer and may serve as an alternative or addendum to traditional chemotherapies. [ABSTRACT FROM AUTHOR]

Abstract CeO 2 -supported Fe 2 O 3 is a satisfactory oxygen carrier for chemical looping hydrogen generation (CLHG). However, the sintering problem restrains its further improvement on redox reactivity and stability. In the present work, a core-shell-structured Fe 2 O 3 /CeO 2 (labeled Fe 2 O 3 @CeO 2) oxygen carrier prepared by the sol-gel method was studied in a fixed bed. The effect of the core-shell structure on the sintering resistance and redox performance was investigated with a homogenous composite sample of Fe 2 O 3 /CeO 2 as a reference. The results showed that the Fe 2 O 3 @CeO 2 exhibited much higher redox reactivity and stability than the Fe 2 O 3 /CeO 2 with no CO or CO 2 observed in the generated hydrogen, while the hydrogen yield for Fe 2 O 3 /CeO 2 decreased with redox cycles due to serious sintering. The satisfactory performance of Fe 2 O 3 @CeO 2 can be ascribed to its high sintering resistance, since the core-shell structure suppressed the outward migration of Fe cations from the bulk to the surface of the particles. On the other hand, the migration of Fe cations and their subsequent enrichment on the particle surface led to the serious sintering of Fe 2 O 3 /CeO 2. The crystallite size evolution of Fe 2 O 3 and CeO 2 in redox cycles further demonstrated the higher sintering resistance of Fe 2 O 3 @CeO 2. Further, the particle size distribution (PSD) results indicated the agglomeration of Fe 2 O 3 /CeO 2 after cycles. In addition, the CeO 2 shell could facilitate the transport of oxygen ions between the iron oxide nanoparticle core and the shell surface. Therefore, the coating of nanoscale Fe 2 O 3 with a CeO 2 shell did not reduce the redox reactivity and stability of Fe 2 O 3 @CeO 2 , but rather promoted it, though less oxygen-ionic-conductive CeFeO 3 was generated. Graphical abstract Image 1 Highlights • A core-shell structured Fe 2 O 3 @CeO 2 prepared by sol-gel method was studied for CLHG. • Fe 2 O 3 @CeO 2 exhibited significantly enhanced sintering resistance. • Fe 2 O 3 @CeO 2 showed much higher activity and stability than the composite Fe 2 O 3 /CeO 2. • Fe 2 O 3 @CeO 2 prevented the outward migration of Fe cations from the bulk to surface. • CeO 2 shell facilitated oxygen mobility between the Fe 2 O 3 core and the shell surface. [ABSTRACT FROM AUTHOR]

Abstract Time-resolved x-ray imaging is used to capture high-resolution images of the Al/Fe 2 O 3 thermite reaction as it proceeds in an extended burn tube. The observed thermite reaction products are generally large, multi-phase composite particles. Image processing algorithms are developed to extract a continuous record of composite particle size as a function of time and distance from the ignition point. Small particles are observed immediately after ignition, followed by a rapid increase in particle size and a gradual decline toward late times. Correlating the dynamic particle size with visible light emission from the reaction, we propose a two-stage mechanism where the combination of early ignition and delayed expansion causes the material closest to the ignition point to undergo substantial coalescence before it begins moving down the tube. We also identify two mechanisms that may contribute to particle size refinement at late times, both based on the collapse of large gas bubbles that are observed preferentially in particles at earlier times. A new approach to extracting burn times from luminous intensity data is explored, and we find that a more nuanced analysis of burn time and luminous intensity may help to improve reactivity assessments when data from in situ studies is unavailable. [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 The super-paramagnetic iron oxide nanoparticles (SPIONs) were synthesized using an environmentally friendly method. The SPIONs with mainly carbohydrate coatings were simply synthesized using a natural, zero calorie sweetener (Stevia) extract (as both reducing and stabilizing agents). The resulting SPIONs were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), High-resolution transmission electron microscopy (HRTEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), vibrating-sample magnetometer (VSM) and Zeta potential test. The SPIONs (smaller than 25 nm) are very stable due to bio-molecular coating because having a zeta potential of −41.1 mV creates opposing forces between nanoparticles and prevents them from gathering. The biogenic SPIONs were able to counteract the effects of oxidative metabolites as studied with the antioxidant activity with an IC 50 of 65 μg/ml. This feature shows the capability of these nanoparticles in designing potential biomedical applications. Graphical abstract Schematic representation of green synthesis of the magnetic iron oxide nanoparticles. Image Highlights • Fe 3 O 4 iron oxide nanoparticles was smaller than 25 nm in size. • The magnitude of the potential Zeta was calculated −41.1 mV. • These biogenic NPs can easily be collected or removed from the environments. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pulsed laser ablation of iron in air led to magnetite and iron nitrides formation. • Lamellas and rolls appear in the sample that was ablated in air, not in Ar-O 2 mixture. • Thermal treatment allowed control of the composition and structure of the material. • Materials obtained with different properties are in demand for different applications. Abstract Magnetic nanoparticles were obtained using the nanosecond pulsed laser ablation (Nd:YAG laser, 1064 nm, 7 ns) of an iron target in air at atmospheric pressure. The particles obtained were further annealed at four different temperatures. The composition, structure and properties of all obtained powders were investigated using X-ray diffraction (XRD), DSC, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, TEM, SAED and other techniques. The initial sample was found to contain monoclinic magnetite and iron nitrides. Presumably, magnetite presents in the form of spherical particles with the distribution maximum of 12–15 nm, and nitrides take the form of lamellas and rolls. Thermal treatment of the sample led to particle enlargement and phase transformations, first, to cubic magnetite, then to a Fe 3 O 4 , α-Fe 2 O 3 and γ-Fe 2 O 3 mixture, and finally to the pure hematite phase. Zeta-potential, BET surface area and magnetic properties changed with the annealing as well. The obtained materials exhibited different properties that make them in demand in different fields, from biomedicine to technology. [ABSTRACT FROM AUTHOR]

Highlights • Morphology engineering on iron oxides is carried out via an electrochemical method. • Morphology transition from zero-dimension to one-dimension is realized. • Iron oxide electrode delivers a high capacity of 184 mAh g−1 at 2 A g−1 (∼6C rate). • The Ni/Fe full cell exhibits a good energy density of 82.3 Wh kg−1. Abstract Aqueous rechargeable Ni/Fe batteries possess potential advantages for large-scale energy storage applications due to their low cost, high safety and fast ion diffusions in electrolyte. However, the electrochemical performance of the iron-based anode is still far from ideal due to particle aggregations. Herein, we carry out the morphology engineering on the iron oxide active materials via a facile electrochemical method to improve its charge storage capability. The morphology transition from zero-dimensional particles to one-dimensional nanorods is realized by tuning the electrolyte composition, while subsequent annealing treatment results in further morphology modification into 3D interconnected nanoparticles (10–20 nm). The hierarchical structure allows facile ion and electron transfers, and the large surface provides various active sites for the charge storage conversion reaction. As a result, even at the high current density of 2 A g−1 (∼6C rate), the iron oxide electrode can still deliver a high specific capacity of 184 mAh g−1. At the same time, the morphology integrity and stability of the electrode leads to a good cycle life, with 87.5% capacity retained upon 5000 cycles. The Ni/Fe full cell assembled with the iron oxide anode and a Ni-Co double hydroxide cathode exhibits a good energy density of 82.3 Wh kg−1 at the power density of 3.3 kW kg−1. Our fundamental study would provide new insights for the electro-deposition of iron-based materials and endow new opportunities for the fabrication of high-performance iron-based electrodes for energy storage systems. [ABSTRACT FROM AUTHOR]

The effectiveness of the current UK iron oxide powder suspension formulation, 'C-IOPS-09' (Triton X-100 based), for fingermark or latent fingerprint visualization is shown to be affected by variations between batches of the recommended iron oxide powder from Fisher Scientific (I/1100/53). When incorporated into the C-IOPS-09 formulation, a 2015 powder batch resulted in the detection of ∼19% fewer fingermarks, of broadly reduced contrast, when compared to powder suspension prepared with a 2008 batch of the same product. Furthermore, the 2015 powder batch was found to be unsuitable in experimental reduced-surfactant concentration powder suspension, because it caused surface-wide or background staining. The studies in this paper also investigated the use of Tween 20 surfactant as an alternative to the currently utilised Triton X-100, in preparation for the potential unavailability of Triton X-100 in the future. Powder suspensions prepared with Tween 20 surfactant solutions of 4% and 40% were shown to offer similar effectiveness to the currently recommended C-IOPS-09 formulation, when compared using the same batch of Fisher Scientific iron oxide powder (2008 or 2015). The difference between the 2008 and 2015 iron oxide batches was hence also evident with these alternative surfactant solutions. Particle size distribution analysis of the iron oxide powders in Tween 20 and Triton X-100 based surfactant solutions show that the more effective powder exhibits a higher sub-micrometre particle population than the less effective powder. This work leads to an improved specification for powder suspension formulations. This is demonstrated with an example powder suspension formulation which uses a 10% Tween 20 surfactant solution and iron oxide nanopowder (50-100nm) from Sigma Aldrich, which was shown to visualise 27% more fingermarks than the C-IOPS-09 formulation prepared with the 2015 Fisher Scientific powder batch, in a comparative study. [ABSTRACT FROM AUTHOR]

Abstract The purpose of the present report was the study and identification of an unspecified sample from a work of art by means only of a microscope coupled to a Raman spectrometer. The origin of the fragment was obscure. The Raman spectra on the virgin sample were giving no results because of a deteriorated surface treatment, in spite of the evident blue color identified by microscopic visual inspection. The sample fragmentation and the preparation of a KBr pellet allowed the distribution of the painting layers of the different components on a flat substrate reducing surface effects. Selecting the areas of different color and focusing there it was possible to identify the pigments from their Raman spectra locally acquired by selective excitation. Raman spectra were assigned by comparison with published databases. It was possible to connect Carbon Black and Orange iron oxide, as documented historically, as constituents of Azurite preparatory layer - "Morellone", according to a technique generally employed to allow the use of Azurite blue pigment on frescos, consequently the identification of typology of work of art was deducted and attributed to a fresco. [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]

Experimental and field measurements have shown that, in the presence of both iron-containing aerosols and sunlight, oxidized mercury species such as HgCl 2 and HgBr 2 undergo reduction to elemental mercury (Hg°), which remains in the atmosphere longer than oxidized mercury species due to its higher volatility. We performed density functional theory (DFT, PW91+ U ) calculations to elucidate the reduction mechanism for atmospheric HgCl 2 and HgBr 2 to Hg° on several iron-oxide aerosol surfaces relevant in the troposphere. On the OH-Fe-R-terminated α-Fe 2 O 3 (0001) surface, predicted to be most prevalent under ambient conditions, we show that: (1) the first Hg-X bond is broken via either thermal or photolytic activation depending on the ambient temperature; (2) photons with an energy of 2.69 eV (461 nm) are required to break the second Hg-X bond; and (3) a photo-induced surface-to-adsorbate charge-transfer process can promote Hg° desorption with an excitation energy of 2.59 eV (479 nm). All the calculated excitation energies are below the threshold value of 3.9 eV (320 nm) for photons in the troposphere, suggesting that sunlight can facilitate mercury reduction on iron-oxide aerosol surfaces. In contrast, the gas-phase reduction of HgCl 2 (HgBr 2 ) involves photoexcitation requiring an energy of 4.98 (4.45) eV (249 (279) nm); therefore, the energy range of sunlight is not suitable for gas-phase reduction. Our computational results provide the first evidence on the detailed mechanism for the combined role of aerosols and photons in the reduction of HgCl 2 and HgBr 2 . Our methodology can be adapted to study other photochemical heterogeneous processes in the atmosphere. [ABSTRACT FROM AUTHOR]

In vivo read-out of autophagy is of great therapeutic and fundamental significance, and yet being conducted exclusively in high cost transgenic animal models. As an attempt to readily monitor the autophagy flux, we herein proposed an autophagy-responsive magnetic resonance imaging based on radical-conjugated magnetic nanoparticles. In principle, both the NO· radical and Fe 3 O 4 nanoparticles are stable, and separately contributing to an observation of enhanced T 1 -and T 2 -weighted imaging, respectively. Meanwhile, the onset of autophagy concomitantly simulates the mass production of reactive species, and consequently quenches the T 1 -signal of NO·. On this basis, the content of autophagy flux is reflected by the ratio of T 1 -signal intensity to that of T 2 -signal, which is condition-insensitive, as a function of time. Assisted with such strategy, an unprecedented protection role autophagy played in respond to heat stress has been revealed, through which the killing effect of magneto-hyperthermia was greatly impeded. Furthermore, we noticed that the impairment of autophagy through the sequential chemotherapy, can markedly improve the therapeutic outcome, in a manner monitored and thoroughly analyzed using the strategy reported herein. We therefore believe that such a study offers a feasible method for in vivo read-out of autophagy and gives us insights how autophagy influences the therapeutic index of cancer treatments. [ABSTRACT FROM AUTHOR]

This study was aimed to explore the effect of phase separation on the Jian ware blue colored glaze with iron oxide. In order to analyze the forming cause of glaze patterns and their coloring mechanism, the phase, microstructure and chemical state of the samples were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectrum. The results indicated that the addition of calcium phosphate introduced highly-active Ca 2+ and P 5+ into the glaze. Since Ca 2+ with high ionic potential had a greater ability to appeal O 2− than Si 4+ , the glaze melt was separated into calcium-rich phase and silicon-rich phase. The difference of viscosity caused the non-uniform distribution of quartz and glass phase, and then affected the distribution of iron ions in two phases, which formed glaze patterns. Adding P 5+ that had a strong effect of reversed polarization on the Fe-O increased the contents of Fe 2+ and Fe 3+ -O-Fe 2+ , and thus deepened the blue-green of glaze surface. In addition, it promoted the formation of worm-like phase-separated structures and the existence of structural color. Therefore, phase separation enriched not only patterns but also glaze colors of the Jian ware blue colored glaze. [ABSTRACT FROM AUTHOR]

• Fe-clay composite is an efficient adsorbent material for phenol removal. • Textural and chemical properties of the adsorbent have been assessed. • Kinetics and thermodynamics studies of phenol adsorption have been performed. • Statistical physics models were applied to understand the adsorption mechanism. Water pollution by phenolic compounds is considered a primary environmental concern. The adsorption of phenol on iron-modified clay and its mechanism were evaluated in this study. A new hybrid material, "Clay-Iron oxide," has been synthesized for its possible use in phenol removal from wastewater. Textural and chemical properties of this new composite have also been assessed using a variety of techniques such as XRD, XRF, SEM-EDX, FTIR, and BET. On the other hand, phenol adsorption performance has been studied in terms of pH, temperature, and initial concentration. Theoretically, the phenol adsorption onto modified clay was satisfactorily modeled with pseudo-second-order kinetics and the Langmuir isotherm; the maximum phenol adsorption capacities, obtained with the Langmuir model, are 15.24, 17.55, 20.24, and 20.10 mg/g at 303, 313, 323, and 333 K, respectively. Furthermore, five advanced statistical physics models were adopted to understand the adsorption mechanism better. The combination of experimental and modeling approaches revealed that: i) the present material is competitive compared to other adsorbents, ii) phenol molecules interact with clay/iron oxide functional groups via several mechanisms, iii) the number of phenol molecules adsorbed per site increases with temperature, iv) phenol adsorption process is spontaneous, physisorption and endothermic, and v) Iron increases the phenol removal efficiency. Thus, the novelty of this research paper lies in the phenol adsorption mechanism study based on the spatial and energetic properties, the determination of the adsorption process effect on the adsorbent, and finally, the assessment of the iron-modified clay's efficiency in removing phenol from wastewater. [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]

In this study, a cellulose/Fe 3 O 4 /Cu composite was synthesized by the blending method and applied as an X-ray radiation apron. The content of Fe 3 O 4 in each sample was 94 wt%, and the varying levels of cellulose and Cu were 1, 2, 3, 4, and 5 wt%. The crystal phase formed in the sample was observed using X-ray diffraction, and the functional group formed was examined using Fourier transform infrared spectroscopy. The performance of the sample as a radiation shield was analyzed using X-ray mobile with energies of 50, 60, 70, 81, and 90 keV at 10 mAs applied to the sample. The results showed that the samples with composition of 2 wt% cellulose and 4 wt% Cu exhibited the best values for the average size of the smallest crystallite size (12.21 nm), low transmittance, linear attenuation coefficient (μ), mass attenuation coefficient (μm), atomic cross-section (σ a), electronic cross-section (σ el), half value layer, and mean free path. Alterations observed on the surface of the composite material suggested the impact of incorporating metallic components into nonmetallic constituents. Surface analysis was conducted using scanning electron microscope and revealed that the surface model resembled Brassica oleracea. This feature is advantageous due to the large surface area and absorbent properties associated with such leaves. • Cellulose/Fe3O4/Cu composite was synthesized by the blending method. • The smallest average crystal size value was 12.21 nm from XRD analysis. • The μ, μ m , σ t , a , and σ t , e l matched theoretical calculation XCOM database. • The best HVL and MFP is for composite with 2% cellulose. [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]

Ultrafine spherical Fe 2 O 3 powders with controllable morphology and crystal phase were synthesized by ultrasonic spray pyrolysis. In this experiment, we chose three common ferric salts (Fe(NO 3 ) 3 ·9H 2 O, FeSO 4 ·7H 2 O or FeCl 2 ·4H 2 O) as precursor solution and regulated the concentration of chlorine ion (Cl − ) in precursor solution to produce Fe 2 O 3 particles. The morphology, crystal structure and magnetic property of prepared Fe 2 O 3 particles were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Vibrating sample magnetometer (VSM). The diameter of the obtained Fe 2 O 3 products ranged from 0.2 to 2 μm. And the product obtained from FeCl 2 precursor solution was magnetic, which was composed of hexagonal α-Fe 2 O 3 and cubic γ-Fe 2 O 3 from XRD results. We also calculated the weight percent of α-Fe 2 O 3 and γ-Fe 2 O 3 in the product through XRD quantitative analysis. However, with the addition of Cl − in Fe(NO 3 ) 3 or FeSO 4 precursor solution, the products turned from non-magnetic to magnetic, whose pure α-Fe 2 O 3 phase became to α-Fe 2 O 3 and γ-Fe 2 O 3 multi-phase. Besides, the weight percent of γ-Fe 2 O 3 and the amount of M s increased with the Cl − concentration in precursor solution improving. According to the research, it can be inferred that the presence of Cl − inhibits the phase transition of γ-Fe 2 O 3 to α-Fe 2 O 3 at high temperature. [ABSTRACT FROM AUTHOR]

Fe 2 O 3 films were deposited on transparent conductive substrates (fluorine doped tin oxide (FTO) on glass) by aerosol pyrolysis. The intrinsic nature of as-deposited films requires the addition of a suitable metal dopant. Sn proved to be well adapted to this task, as it increased photocurrents in junctions with an aqueous electrolyte by one order of magnitude as compared to undoped films. The maximum IPCE value (incident photon to current conversion efficiency) was 0.21 at 400 nm for a 120 nm thick film and a maximum photocurrent of 1630 μA/cm 2 at 0.65 V vs. Ag/AgCl under simulated solar irradiation. [ABSTRACT FROM AUTHOR]

First-principle calculations are carried out to interpret the experimental observations and to generate the mechanisms of CO and CH 4 conversion with Fe 2 O 1-3 . The stabilization of Fe C bonding involves π ∗ (C O) and electron donating from oxygens’ LP. The Fe O bond activation is rate-limiting step of conversions. Stabilization and activation are affected by number of oxygens at the iron active site. Low ORBs are identified for CO + Fe 2 O 1-3 reaction pathways. Significant ORBs are calculated for Fe 2 O 3  + CH 4 , and the competing mechanism of reduction by H 2 is shown. DFT calculations suggest favorable formation of Fe 3 C in atmosphere of CH 4 and its oxidation in atmosphere of CO. [ABSTRACT FROM AUTHOR]

With copper and iron oxides as colorants, reddish and bluish purple glazes were prepared by changing the raw material ratio at the same firing schedule. Based on the primary factor experiments and the analyses of XRF and SEM/EDS, the fambe mechanism was proposed. The results indicated that glaze colors were related to multiple factors. The difference in copper red and purple glazes was merely caused by the later ingredient containing Ca 3 (PO 4 ) 2 , in which liquid-liquid phase separation structures were developed and formed structural colors, while the accumulated Fe 2 O 3 in one phase decomposed to Fe 2+ and bubbles to form blue stains and colorful texture. In addition, both CuO and Fe 2 O 3 had a variety of coloring characteristics, which depended on the process parameter, firing temperature and base glaze compositions to make colors and hues change accordingly. In such cases, the multiple chemical colors were coupled with structural colors to form the fambe glaze. [ABSTRACT FROM AUTHOR]

Urchin-like α-Fe 2 O 3 /MnO 2 hierarchical hollow composite microspheres have been synthesized by using carbon as sacrificial templates. By combining the advantages of Fe 2 O 3 with high electrical conductivity and MnO 2 with high theoretical capacity, the urchin-like α-Fe 2 O 3 /MnO 2 composites present better electrochemical performances as a lithium ion battery anode compared with α-Fe 2 O 3 hollow spheres and MnO 2 hollow spheres. The α-Fe 2 O 3 /MnO 2 composites exhibit high initial discharge capacity of 1531 mAhg −1 and excellent reversible capacity of 860 mAhg −1 after 150 cycles at 0.1Ag −1 . Furthermore, the composites retain a discharge capacity of 494 mAhg −1 after 500 cycles at 0.5 Ag −1 . The excellent performances may originate from reinforced structural stability, large surface area and good electrical conductivity. The urchin-like α-Fe 2 O 3 /MnO 2 composite material may serve as a potential anode material for lithium-ion battery. [ABSTRACT FROM AUTHOR]

Electrode materials with high specific capacity and cycle stability are the key factors that determine the overall performance of lithium ion batteries (LIBs) for new smart electronic device, and such materials with high performance are still challenging. Here, we report a composite material Carbon nanotube @ Iron oxide @ Carbon (γ-CNTs@γ-Fe 2 O 3 @C) with coaxial cable structure in hydrothermal method with the assistance of glucose. The as-prepared composite materials show superior electrochemical properties with good rate capability and excellent cycling performance, which show the great potential of CNTs@γ-Fe 2 O 3 @C for practical production and application in energy devices. [ABSTRACT FROM AUTHOR]