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The present work is aimed at developing an effective graphene-based sorbent for liquid-phase sorption of organic pollutants from aquatic media. The material synthesized in accordance with the method proposed represents a nanostructured composite possessing the hydrogel properties: structured three-dimensional carbon framework surface-modified with iron nanoparticles (i.e., graphene oxide (GO)/Fe-H2O). Moreover, the proportion of dry matter in the hydrogel was revealed by drying to a constant weight at a given temperature (110 °C), and the powdery form (GO/Fe-110) of the composite was obtained. Besides, the aerogel (GO/Fe-250) of the composite developed was formed, for which the hydrogel synthesized was subjected to hydrothermal drying in isopropanol for 6 h under supercritical conditions. The morphological, structural and porous characteristics of all these materials were determined. The sorption capacity of the nanocomposites was estimated for the removal (under dynamic conditions) of the synthetic organic dye, methylene blue, used as a target pollutant. The results of the studies showed that the maximum sorption capacity of the GO/Fe-H2O, GO/Fe-110 and GO/Fe-250 are ∼2500, ∼1500 and ∼2300 mg g−1, respectively. Besides, the high rate of the target pollutant removal from the aquatic media is a distinctive feature of the composites developed herein. [ABSTRACT FROM AUTHOR]

Although β-Fe2O3 has a high theoretical solar-to-hydrogen efficiency because of its narrow band gap, the study of β-Fe2O3 photoanodes for water splitting is elusive as a result of their metastable nature. Raman identification of β-Fe2O3 is theoretically and experimentally investigated in this study for the first time, thus clarifying the debate about its Raman spectrum in the literature. Phase transformation of β-Fe2O3 to α-Fe2O3 was found to potentially take place under laser and electron irradiation as well as annealing. Herein, phase transformation of β-Fe2O3 to α-Fe2O3 was inhibited by introduction of Zr doping, and β-Fe2O3 was found to withstand a higher annealing temperature without any phase transformation. The solar water splitting photocurrent of the Zr-doped β-Fe2O3 photoanode was increased by 500% compared to that of the pure β-Fe2O3 photoanode. Additionally, Zr-doped β-Fe2O3 exhibited very good stability during the process of solar water splitting. These results indicate that by improving its thermal stability, metastable β-Fe2O3 film is a promising photoanode for solar water splitting. [ABSTRACT FROM AUTHOR]

Inorganic nanoparticles provide multipurpose platforms for a broad range of delivery applications. Intrinsic nanoscopic properties provide access to unique magnetic and optical properties. Equally importantly, the structural and functional diversity of gold, silica, iron oxide, and lanthanide-based nanocarriers provide unrivalled control of nanostructural properties for effective transport of therapeutic cargos, overcoming biobarriers on the cellular and organismal level. Taken together, inorganic nanoparticles provide a key addition to the arsenal of delivery vectors for fighting disease and improving human health. Unlabelled Image [ABSTRACT FROM AUTHOR]

Background: This study aims to evaluate the antibacterial activity of chitosan-coated iron oxide nanoparticles (Chi-IONP) by agar direct diffusion method and determine the minimum inhibitory concentration and minimum bactericidal concentration (MIC/MBC) of this nanosolution against E.faecalis, S.mutans and Candida albicans the three oral microorganisms commonly isolated from endodontic infections. Methods: The nanoparticles solution was prepared by functionalizing the 8nm iron oxide nanoparticles with glycine and coating them by chitosan dissolved in 0.25% v/v acetic acid. E.faecalis, S.mutans and candida albicans were isolated and identified with Vitek 2 system. Agar diffusion method was used to test three groups of materials, NaOCl 5.25% serve as positive control, 0.25% Acetic acid as negative control and Chi-IONP as experimental material. Broth microdilution method used to determine the MIC/MBC of the experimental material. Statistical analysis used: Statistical analysis was conducted by independent variables t-test performed by using IBM-SPSS program version 22. Result: The used microbial isolates were confirmed with Vitek 2 system with excellent confidence level of diagnosis. Chi-IONP showed antifungal activity higher than NaOCl 5.25%, and comparable effect to NaOCl 5.25% against E.faecalis and S.mutans. The negative group showed no effect on the tested microorganisms. The MIC/MBC were determined as following 125/250 μg/ml for E.faecalis, 250/ 500μg/ml for S.mutans and the MIC/MFC was 62.5/ 125 μg/ml for C.albicans. Conclusion: Chi-IONP was a powerful antimicrobial agent against the tested microorganisms, and this test results shows antifungal activity of Chi-IONP higher than NaOCl 5.25% and comparable antibacterial effect to NaOCl 5.25%. [ABSTRACT FROM AUTHOR]

In this work, the multicomponent nanocomposites containing filamentary carbon nanostructures were synthesized using materials based on iron oxides with a predominant content of the epsilon phase (ε-Fe2O3). These iron oxide-based materials were obtained by a direct plasma-dynamic synthesis with supersonic outflow of an iron-containing electric discharge plasma into an oxygen atmosphere. Subsequently, they were used as an initial precursor and placed in the plasma-chemical reactor, where the multicomponent C/SixOy/Fe2O3 nanostructures were synthesized under the influence of the pulsed electron beam. This method was based on the volume excitation of the reaction gas by a pulsed electron beam in such a way as to control the uniform process implementation in the entire excitation region. The morphology and phase composition of the synthesized C/SixOy/Fe2O3 nanocomposites were studied. A typical morphological feature of the C/SixOy/Fe2O3 samples was found to be the formation of filamentary nanostructures. Their diameter does not exceed 10–20 nm, while their length varies up to 1 μm. [ABSTRACT FROM AUTHOR]

We constructed a multifunctional (Fe3O4/nGO)@mSiO2/GQDs drug carrier for loading and microwave-controlled release of an etoposide (VP16) as the anticancer drug. This nanocomposite consisted of magnetic core Fe3O4, microwave-absorbing nanographene oxide (nGO), fluorescent graphene quantum dots (GQDs) and intermediate barrier layer (mesoporous silica). It has a large surface area of 359.8 m2/g, excellent fluorescence emission and ample magnetic performance of 36.00 emu/g. After microwave irradiation for 140 s, the temperature of (Fe3O4/nGO)@mSiO2/GQDs nanoparticles rapidly went up to 90∘C. The loading rate of VP16 was as high as 68%, the release rate reached 87% within 280 min under microwave irradiation. Therefore, the functionalized (Fe3O4/nGO)@mSiO2/GQDs nanoparticles will have potential application for clinical treatment as drug delivery system. The (Fe3O4/nGO)@mSiO2/GQDs nanoparticles were synthesized through introducing GQDs based on HMFG prepared previously. The nGO could distinctly improve the performance of microwave thermal conversion, drug loading and the microwave-controlled release of the drug carrier. The GQDs could promote the fluorescence detection performance. Additionally, the modification of the mesoporous silica thin layer onto the surface of HMFG is beneficial for increasing the loading of GQDs and drugs, in the meantime, to prevent the quenching of GQDs from nGO. [ABSTRACT FROM AUTHOR]

Iron oxide nanoparticle fabrications have gained increasing attention owing to their vital role in industrial application. Taking green synthesis of nano-products into account, this experiment was conducted to provide a simple, facile, economic, and fast procedure for the biosynthesis of Fe2O3 nanoparticles using fruit extracts of Cornelian cherry. The FTIR spectroscopy revealed that hydroxyl and amino groups have the ability to perform dual functions of reduction and stabilization of iron oxide nanoparticles. XRD analysis manifested the crystal structure of the Fe2O3 nanoparticle. The SEM image of synthesized Fe2O3 nanoparticle demonstrated the morphology of nanoparticles is spherical. Transmission electron microscopy (TEM) images showed very fine spherical Fe2O3 nanoparticles ranging from 20 to 40 nm. The EDXRF spectra displayed only iron and oxygen elements, which implies that the sample is highly pure Fe2O3 nanoparticle. The Fe2O3 nanoparticle and its bulk form at the concentrations ranging from 10 to 100 mg L−1 showed statistically significant stimulation in both root and shoot biomass. However, Fe2O3 nanoparticle was more effective than the bulk to stimulate barley growth. The findings may be functionalized in the production and formulations of nano-based fertilizers. [ABSTRACT FROM AUTHOR]

Summary: Chemical looping using methane offers the potential for producing syngas or hydrogen with intrinsic separation of CO2. An ilmenite (FeTiO3)‐based oxygen carrier is a suitable oxygen carrier for methane oxidation because of good reactivity and low cost. However, it underwent a phase separation during repeated redox cycles, thereby resulting in the decrease in the reactivity. Therefore, it is necessary to develop a TiO2‐supported iron oxide composite with high redox stability and reactivity. In this study, we synthesize a titania‐doped YSZ (Y0.20Ti0.15Zr0.65O1.90)‐promoted iron‐based oxygen carrier. Inert material (ZrO2), pure ionic material (YSZ), and electronic conductive material (TiO2) are used as support materials for comparison. It is found that the Y0.20Ti0.15Zr0.65O1.90 promotes iron‐based oxygen carrier showed the best performance (27%/min to achieve 66% conversion) in methane oxidation in TGA experiment, high syngas selectivity in fixed bed reactor, and the redox stability over 100 redox cycles. Meanwhile, the other oxygen carriers show low reactivity and the morphological changes (iron oxide layer) and/or the phase decomposition (ie, YSZ → Y2O3 and ZrO2 and Fe2TiO5 → Fe2O3 and TiO2). The enhanced reactivity and stability are mainly ascribed to the mixed ionic‐electronic conductivity and the redox stability of titania‐doped YSZ in the single‐phase fluorite region. [ABSTRACT FROM AUTHOR]

Entropy generation in peristaltic transport of nanomaterial with iron oxide is discussed. MHD and Joule heating are analyzed. Energy equation further consists of heat source/sink and viscous dissipation. Velocity slip and temperature jump conditions are also accounted. Large wavelength analysis is carried out. Results for velocity, temperature, pressure and entropy generation are presented graphically. Temperature decreases by increasing nanomaterials' volume fraction. Larger velocity slip parameter yields lower pressure gradient. Entropy generation is increased for Hartmann number and nanoparticle volume fraction. [ABSTRACT FROM AUTHOR]

The utilization of novel materials within the scope of biofuel synthesis has been represented as a significant step in the development of remarkable catalysts. The use of lipases in biodiesel production is often found as a cost-limiting step, as the operational expenditures in recovering such catalysts may lead to unfeasible market expectations. Herein, magnetic-polymer composites were evaluated as supports to immobilize commercial lipase, following the application in ethyl ester syntheses. A matrix of polysiloxane-polyvinyl alcohol (SiO 2 -PVA) was selected as the polymeric structure, following Fe 3 O 4 and γFe 2 O 3 coating and incorporation assays to the support backbone. Characterization of the produced catalyst support materials was performed via analysis of X-ray powder diffraction, pore size, Scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. Burkholderia cepacia was then immobilized on the matrices, following transesterification of coconut oil with ethanol. The biodiesel samples generated were all within commercial standards, achieving conversion ester contents higher than 96.5%. The purified product samples (biodiesel) were essentially odorless and translucent appearance. Other properties such as density (873–876 kg m−3) and viscosity (3.76–3.93 mm2 s−1) meet the specifications required by the ASTM to be used as a biofuel. Image 1 • Iron oxides were added to SiO 2 -PVA structure and used as lipase support. • Coating and incorporation of Fe-oxides were tested on the SiO 2 -PVA structure. • Immobilized lipase demonstrated to be efficient in ethyl esters formation (>96.5%). • Fe-oxides incorporated into the SiO 2 -PVA matrix provided 85.9% of activity recovery. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles in general, and iron oxide nanoparticles in particular, have been studied extensively during the past 20 years for numerous biomedical applications. The main applications of these nanoparticles are in magnetic resonance imaging (MRI), magnetic targeting, gene and drug delivery, magnetic hyperthermia for tumor treatment, and manipulation of the immune system by macrophage polarization for cancer treatment. Recently, considerable attention has been paid to magnetic particle imaging (MPI) because of its better sensitivity compared to MRI. In recent years, MRI and MPI have been combined as a dual or multimodal imaging method to enhance the signal in the brain for the early detection and treatment of brain pathologies. Because magnetic and iron oxide nanoparticles are so diverse and can be used in multiple applications such as imaging or therapy, they have attractive features for brain delivery. However, the greatest limitations for the use of MRI/MPI for imaging and treatment are in brain delivery, with one of these limitations being the brain-blood barrier (BBB). This review addresses the current status, chemical compositions, advantages and disadvantages, toxicity and most importantly the future directions for the delivery of iron oxide based substances across the blood-brain barrier for targeting, imaging and therapy of primary and metastatic tumors of the brain. Magnetic forces could be used in the controlled delivery of injected magnetic iron oxide nanoparticles (IONPs) for imaging, targeting and treatment of brain tumors. Unlabelled Image [ABSTRACT FROM AUTHOR]

• The Vo content of Fe 2 O 3 nanoplates is tuned by annealing at different temperatures. • Fe 2 O 3 with the oxygen vacancy content of 17% has the highest capacity. • The SSC shows a high energy density of 58.5 Wh kg−1 at a power density of 9.32 kW kg−1. As a promising anode material for supercapacitors, Fe 2 O 3 has been widely studied but still face the problem of low conductivity. Inducing oxygen vacancy (Vo) into Fe 2 O 3 is a widely used approach to tune the conductivity to enhance its capacitive performance, but there is little research on the influence of Vo content. Herein, we report the effect of Vo in Fe 2 O 3 nanoplates with various content. We tuned the Vo content by annealing at 200–500 °C. XPS and EPR were taken to characterize the Vo content, ranging from 11% to 26%. Electrochemical results show that FO-300 with 17% Vo has the highest capacity of 301 mAh g−1, and the capacity of the highest Vo content's (26% Vo) is only 107 mAh g−1. The symmetric supercapacitor based on FO-300 shows a considerably high energy density of 58.5 Wh kg−1 at a power density of 9.32 kW kg−1 and remains 84.6% after 12,000 cycles. [ABSTRACT FROM AUTHOR]

This study aims the synthesis of a novel functionalized magnetic nanocarrier based on xanthan gum biopolymer. Glycidyl methacrylate was grafted on xanthan gum chains by radical polymerization reaction using two types of initiators: ammonium persulfate and benzoyl peroxide. Characterization studies of the magnetic nanocarrier were performed using several instruments such as Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy-Dispersive-X-Ray Spectroscopy, X-Ray Diffraction Spectroscopy, Transmission Electron Microscopy, Mossbauer Spectroscopy, and Vibrating Sample Magnetometer. According to the Vibrating Sample Magnetometer data and Mossbauer analysis, Fe atoms were incorporated successfully in the polymer chains in Fe3+ state and magnetic nanocarrier has super-paramagnetic behavior, respectively. Epoxy groups on magnetic nanoparticles were converted to carboxylic acid groups using iminodiacetic acid and then tested to usability as a carrier for immobilization of proteins such as albumin, lipase and cytochrome c. The adsorption of albumin and lipase on magnetic nanoparticles were pH-dependent while cytochrome c was immobilized in a wide range of pH value. The calculated maximum experimental immobilization capacity of magnetic nanoparticles was 65.10 mg g−1, 62.0 mg g−1 and 188.0 mg g−1 for albumin, lipase and cytochrome c, respectively. Experimental data fitted to Langmuir isotherm better than Freundlich. The rate of cytochrome c adsorption followed the pseudo-second-order kinetic. Results showed that the functionalized magnetic nanoparticles can be effectively used as a carrier for protein separations, especially for cytochrome c. Moreover, the functionalized magnetic nanocarrier had high affinity to Cytochrome c protein even in multiple protein systems. [ABSTRACT FROM AUTHOR]

This study aims to identify the content and particle shape, and to determine the type, of iron oxide in the magnetic material from Aceh iron sand. The samples were taken from four seacoast locations, namely Mon Klayu, Mantak Tari, Lam Panah and Syiah Kuala beaches. The magnetic materials are separated from the iron sand using an external magnet, washed out with distilled water and dried at 80 °C. The materials were characterized by XRD and SEM. The results show that the magnetic materials sampled from Aceh iron sand contain 88.93, 96.3, 92 and 85% of Fe, respectively. The iron oxide found in Aceh iron sand was predominantly magnetite (Fe3O4) or ilmenite (Fe, Ti3)O4; however, there are also other oxide impurities, such as silica and chromium oxides. The identified minerals were classified as lithogenous sedimentary volcanic minerals, which have a black colour and spherical shape. Related to that, the sampling locations of these minerals were types of volcanic minerals and lithogenous sediments, since the position of the coast locations is adjacent to Burni Telong, Peut Sago and Seulawah volcanos, and the minerals are carried by the stream to the beaches through the river flow, which further supports the assumption of their volcanic origins. [ABSTRACT FROM AUTHOR]

Ambient air pollution is a leading risk factor for the global burden of disease. One possible pathway of particulate matter (PM)-induced toxicity is through iron (Fe), the most abundant metal in the atmosphere. The aim of the review was to consider the complexity of Fe-mediated toxicity following inhalation exposure focusing on the chemical and surface reactivity of Fe as a transition metal and possible pathways of toxicity via reactive oxygen species (ROS) generation as well as considerations of size, morphology, and source of PM. A broad term search of 4 databases identified 2189 journal articles and reports examining exposure to Fe via inhalation in the past 10 years. These were sequentially analyzed by title, abstract and full-text to identify 87 articles publishing results on the toxicity of Fe-containing PM by inhalation or instillation to the respiratory system. The remaining 87 papers were examined to summarize research dealing with in vitro, in vivo and epidemiological studies involving PM containing Fe or iron oxide following inhalation or instillation. The major findings from these investigations are summarized and tabulated. Epidemiological studies showed that exposure to Fe oxide is correlated with an increased incidence of cancer, cardiovascular diseases, and several respiratory diseases. Iron PM was found to induce inflammatory effects in vitro and in vivo and to translocate to remote locations including the brain following inhalation. A potential pathway for the PM-containing Fe-mediated toxicity by inhalation is via the generation of ROS which leads to lipid peroxidation and DNA and protein oxidation. Our recommendations include an expansion of epidemiological, in vivo and in vitro studies, integrating research improvements outlined in this review, such as the method of particle preparation, cell line type, and animal model, to enhance our understanding of the complex biological interactions of these particles. [ABSTRACT FROM AUTHOR]

Magnetic and fluorescent-based sensors have demonstrated widely applications due to their easily recycle and quickly optical response. However, the complex synthesis and weaker function of these sensors limit their practical applications. Herein, an unmodified, magnetic-functionalized carbon dots-based fluorescent sensor has been developed for label-free detection of pH and Cu 2 + with high sensitivity. The sensors can not only reversibly quench and recover the fluorescence signals in response to the variation of surrounding environment including pH and Cu 2 + , but also be used as a high-efficiency recyclable adsorbent for removing Cu 2 + , Hg 2 + , Cr 3 + and Pb 2 + from aqueous solution. For the first time, an unmodified, magnetically functionalized, carbon-dot-based fluorescent sensor was successfully prepared by the hydrothermal method for the detection of pH and Cu2+ with high sensitivity and without labeling. Fe3O4@C-CDs NPs have excellent PL, hydrophilic surfaces, superparamagnetism and high magnetization, making them ideal sensors for monitoring chemical/physical changes and separating waste from aqueous solutions in practical applications. [ABSTRACT FROM AUTHOR]

In this work, PdFe 2 O 3 bimetallic materials containing oxygen vacancies (O v , from 10 to 75%) and two bimetallic nanoparticles based on noble metals (PdAu and PdPt) were obtained and evaluated for the ethanol electro‒oxidation reaction (EOR) in alkaline medium. For this purpose, bimetallic nanoparticles were synthesized keeping similar crystallite sizes (~6 nm), particle sizes (~6 nm), mass compositions (18 ± 4% co‒metal) and metallic loadings (18.3 ± 5.1%). PdAu/C, PdPt/C and the most active PdFe 2 O 3 /C material (75% of O v) displayed an improved onset potential (E onset) during the oxidation of 1.5 M ethanol in 0.3 M KOH in comparison with a monometallic Pd/C material, finding the trend: PdAu/C (−0.56 V vs. NHE) > PdPt/C (−0.55 V) > PdFe 2 O 3 /C (−0.51 V) > Pd/C (−0.50 V). In addition, these bimetallic materials presented an increase in the current density; being PdPt/C and PdFe 2 O 3 /C the most active materials for EOR. A spectroelectrochemical analysis was performed by coupling a μRaman spectroscope with an electrochemical cell. This analysis allowed to conclude that the improvement of the E onset is related to changes in chemisorption energies as was suggested by Raman shifts found for the C 1 ‒M (metal) bond, while the high activity of PdPt/C can be attributed to a higher adsorption of ethanol molecules. Additionally, it was found that the activity of PdFe 2 O 3 /C is associated with an energy decrease to form the C 1 ‒M bond, which could be promoted by the abundance of oxygen vacancies. PdFe 2 O 3 and two bimetallic nanoparticles based on noble metals (PdAu and PdPt) were synthesized and tested for ethanol electro-oxidation. The presence of oxygen vacancies in PdFe 2 O 3 improved the activity displaying similar mass activity than PdPt and higher than PdAu. Spectroelectrochemical tests revealed that the improved activity was related to changes in chemisorption energies due to shifts found for the C 1 ‒M (metal) bond. Image 1 • PdFe 2 O 3 , PdAu and PdPt with similar particle size (6 nm) and loading were obtained. • Improvements on E onset were found to be related to changes in C 1 ‒M (metal) bond. • PdFe 2 O 3 displayed higher activity than PdAu and similar activity than PdPt. • The improved activity of PdFe 2 O 3 was related to the presence of oxygen vacancies. [ABSTRACT FROM AUTHOR]

Laboratory experiments were conducted to study the photocatalytic capability of amorphous α-Fe2O3 to degrade polycyclic aromatic hydrocarbons (PAHs). Solutions containing 16 US EPA priority PAHs were spiked with Fe2O3 and incubated in a climate chamber at stable conditions of temperature (20°C) and light (9.6 W·m−2) for 28 days. In addition, samples without Fe2O3 were also incubated. PAHs levels were monitored by means of GC–MS, and their toxicity was assessed using Microtox® bioassay. Fe2O3 had a significant photocatalytic effect on fluorene, phenanthrene, and benzo(a)pyrene, the photodegradation rate of the latter being 71% and 50% in presence and absence of Fe2O3, respectively. On the other hand, photolysis was significantly higher than photocatalysis for benzo(a)anthracene and dibenzo(ah)anthracene. Photodegradation of anthracene was notably the same regardless of Fe2O3 presence. Remaining PAHs were not photodegraded, neither with, nor without Fe2O3. These results indicated that, in some cases, Fe2O3 might act as a shield for PAHs by hindering their photodegradation. Other factors, such as the chemical structure of the Fe2O3, and also the absence of the soil matrix components (i.e., humic acid, other metals oxides, and texture) could also play a role. Photodegradation trends were supported by changes of EC50 values, suggesting the formation of more bioavailable or toxic PAHs by-products when Fe2O3 and light were present. [ABSTRACT FROM AUTHOR]

Fe–Mn/γ-Al2O3 catalysts that prepared by the wet-impregnation method were used to degrade toluene, a VOCs model compound. The results indicated that the 10Fe–15Mn/γ-Al2O3 exhibited 95% of toluene conversion as well as 95% of CO2 yield at 300 °C. The Fe–Mn/γ-Al2O3 showed a better toluene oxidation activity with respect to the Fe/γ-Al2O3 and Mn/γ-Al2O3. The introduction of Fe into the Mn/γ-Al2O3 resulted in higher surface area, higher Mn3+/(Mn3+ + Mn4+) ratio, lower reduction temperature, and homogenous distribution of Mn. Meanwhile, the co-exist of the Fe3+ and Mn3+ over the 10Fe–15Mn/γ-Al2O3 also favored for the oxygen transfer, which may enhance the catalytic oxidation performance. The initial toluene was adsorbed on surface of the catalysts and formed benzoyl oxide (C6H5–CH2–O), and then the benzoyl oxide (C6H5–CH2–O) was oxidized to benzaldehyde. Furthermore, the benzaldehyde was further oxidized to form benzoic acid that could be converted to CO2 and H2O. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting is a promising method for the conversion of solar energy into chemical energy stored in the form of hydrogen. Nanostructured hematite (α‐Fe2O3) is one of the most attractive materials for a highly efficient charge carrier generation and collection due to its large specific surface area and the short minority carrier diffusion length. In the present work, the PEC water splitting performance of nanostructured α‐Fe2O3 is investigated which was prepared by anodization followed by annealing in a low oxygen ambient (0.03 % O2 in Ar). It was found that low oxygen annealing can activate a significant PEC response of α‐Fe2O3 even at a low temperature of 400 °C and provide an excellent PEC performance compared with classic air annealing. The photocurrent of the α‐Fe2O3 annealed in the low oxygen at 1.5 V vs. RHE results as 0.5 mA cm−2, being 20 times higher than that of annealing in air. The obtained results show that the α‐Fe2O3 annealed in low oxygen contains beneficial defects and promotes the transport of holes; it can be attributed to the improvement of conductivity due to the introduction of suitable oxygen vacancies in the α‐Fe2O3. Additionally, we demonstrate the photocurrent of α‐Fe2O3 annealed in low oxygen ambient can be further enhanced by Zn‐Co LDH, which is a co‐catalyst of oxygen evolution reaction. This indicates low oxygen annealing generates a promising method to obtain an excellent PEC water splitting performance from α‐Fe2O3 photoanodes. [ABSTRACT FROM AUTHOR]

Smart controlling the structure and composition of hybrid anode materials to boost the electrochemical performance is still challenging yet significant for lithium ion batteries (LIBs). Herein, a biomimetic strategy is reported for the synthesis of mesostructured Fe3O4@N‐doped carbon (Fe3O4@CN) hybrid anodes, inspired by structural features and hybrid compositions of the biomineralized mesocrystals. By using the regenerated silk fibroin (RSF)‐biomineralized hematite (ɑ‐Fe2O3) as a single precursor (RSF‐Fe2O3) followed by a simple annealing treatment, its interspaced RSF‐templates can be carbonized in situ to a kind of RSF‐derived CN material, which can further reduce the ɑ‐Fe2O3 to Fe3O4, generating Fe3O4@CN hybrid mesocrystal. Such a biomimetically designed hybrid mesostructure concurrently possesses electrochemically favorable features with abundant internal voids and uniformly introduced carbonaceous layer. Owing to these distinctive structural and compositional merits, the Fe3O4@CN electrode exhibits remarkable lithium storage properties embracing high capacity, outstanding rate capability, as well as long‐term stable cycling life. [ABSTRACT FROM AUTHOR]

Solar redox reforming is a process that uses solar radiation to drive the production of syngas from natural gas. This approach caught attention in recent years, because of substantially lower reduction temperatures compared to other redox cycles. However, a detailed and profound comparison to conventional solar reforming has yet to be performed. We investigate a two-step redox cycle with iron oxide and ceria as candidates for redox materials. Process simulations were performed to study both steam and dry methane reforming. Conventional solar reforming of methane without a redox cycle, i.e. on an established catalyst was used as reference. We found the highest efficiency of a redox cycle to be that of steam methane reforming with iron oxide. Here the solar-to-fuel efficiency is 43.5% at an oxidation temperature of 873 K, a reduction temperature of 1190 K, a pressure of 3 MPa and a solar heat flux of 1000 kW/m2. In terms of efficiency, this process appears to be competitive with the reference process. In addition, production of high purity H 2 or CO is a benefit, which redox reforming has over the conventional approach. • Solar redox reforming and solar conventional reforming are simulated. • Iron oxide and ceria-based redox cycles are compared. • Efficiency and product quality are evaluated. • Impact of solar flux and solid-solid heat recovery is analyzed. [ABSTRACT FROM AUTHOR]

Synthesis and characterization of FexOy nanoparticles were carried out in order to study reaction parameters influence in a spray flame reactor. FexOy powders were prepared with three different precursors aiming to understand how the reactor conditions, dispersion gas flow, and precursor solution flow affect morphology, shape, particle size distribution, crystalline phases, and residue content of the obtained materials. Thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy (TEM), x-ray diffraction (XRD), and Raman spectroscopy were employed to characterize the materials. In addition, magnetic behavior of the obtained samples was evaluated. It was found that the evaluated parameters influenced the residue contents obtaining weight changes from 10 to 35%. Particle size distribution centers also showed differences between 17 and 24 nm. By XRD, Raman, and TEM, the presence of hematite (a-Fe2O3), maghemite (γ-Fe2O3), and magnetite (Fe3O4) was evidenced and explained based on the gas and liquid content in the flame. Additionally, the saturation magnetization was measured for selected samples, obtaining values between 26 and 32 emu g−1. These magnetic measurements were correlated with the crystalline phase composition and particle size distributions. [ABSTRACT FROM AUTHOR]

In this article, the recent applications of different types of magnetic nanoparticles such as α-Fe2O3 (hematite), γ-Fe2O3 (maghemite), Fe3O4 (magnetite), hexagonal (MFe12O19), garnet (M3Fe5O12) and spinel (MFe2O4), where M represents one or more bivalent transition metals (Mn, Fe, Co, Ni, Ba, Sr, Cu, and Zn), and different materials for coating the surface of magnetic nanoparticles like poly lactic acid (PLA), doxorubicin hydrophobic (DOX-HCL), paclitaxel (PTX), EPPT-FITC, oleic acid, tannin, 3-Aminopropyltriethoxysilane (APTES), multi-wall carbon nanotubes (CNTs), polyethylenimine (PEI) and polyarabic acid in drug delivery, biomedicine and treatment of cancer, specially chemotherapy, are reviewed. MNPs possess large surface area to volume ratios because of their nano-size, low surface charge at physiological pH and they aggregate easily in solution due to their essential magnetic nature. These materials are widely used in biology and medicine in many cases. One targeted delivery technique that has gained prominence in recent years is the use of magnetic nanoparticles. In these systems, therapeutic compounds are attached to biocompatible magnetic nanoparticles and magnetic fields generated outside the body are focused on specific targets in vivo. The fields capture the particle complex, resulting in enhanced delivery to the target site. Also, the application of brand new supermagnetic nanoparticles, like Ba,SrFe12O19, is considered and studied in this paper. [ABSTRACT FROM AUTHOR]

The production of nanoparticles (NPs) has increased significantly, given that they have numerous commercial and medical applications. There might have some risk associated with the release of these NPs in the environment. To assess the possible risk of releases of NPs in the groundwater, it is important to evaluate the fate and transport behaviour of NPs through porous media. The objective of this study is, therefore, to evaluate the transport behaviour of widely used NPs [i.e., silver (Ag), iron oxide (FexOy), titanium dioxide (TiO2) and zinc oxide (ZnO)] through porous media in the presence and/or absence of organic matter [i.e., humic acid (HA)] under controlled de-ionized and natural groundwater condition. To achieve the objective, first, the detailed characterizations of NPs are carried out in the presence and absence of HA. Column transport experiments were performed using a 1-D sand-packed column. Different NPs were injected from one end of the column with a flow rate of 0.0054 cm/sec. The result suggests that nAg, nTiO2, and nZnO particles are colloidal stable in the suspension, while nFexOy particles tend to aggregate and settle down very rapidly. However, in the presence of HA, the colloidal stability of nFexOy in the suspension increases significantly. Evaluation of transport behaviour of different metal NPs suggests that a high amount of nFexOy (C/C0=0.01) and nZnO (C/C0=0.09) particles are retained in the porous media. However, in the presence of HA, the transport efficiency of nFexOy (C/C0=0.64) increases significantly. The extensively high amount of nAg and nTiO2 particles are transported in the absence/presence of HA. The surface charge of particles and thus the interaction energy between the NPs and the sand is the main factor controlling the deposition of NPs. Overall, it could be stated that there is a risk of migration of nAg and nTiO2 particles irrespective of the presence of organic matter or of nFexOy particles in the presence of organic matter through the aquifer porous media. However, in the natural groundwater system, when the different ion is present, the extent of transport of NPs is expected to be less, and the risk associated with releasing of NPs in the groundwater would be comparatively low than that is predicted under the controlled de-ionized water condition. However, the nTiO2 particles always have a high risk of release into the groundwater. [ABSTRACT FROM AUTHOR]

An improved hematite α‐Fe2O3 catalysts composed of uniform nanodisks closed with (0001) basal facets and {11‐20} side facets are prepared via a simple hydrothermal route. Moreover, by simply tuning the mass of the reaction precursors of Fe(NO3)3⋅9H2O, the size of the obtained hematite α‐Fe2O3 nanodisks is controlled in the range of 600–100 nm in diameter and 43–230 nm in thickness, respectively. Due to the exposed (0001) basal facets and {11‐20} facets, in which more amount of Fe3+ ion involved, the obtained α‐Fe2O3 nanodisks exhibit enhanced reducibility. The maximum H2 consumption occurs at relative lower temperature, ca. 490 °C for the smallest α‐Fe2O3 nanodisks of 43 nm in thickness and 100 nm in diameter, respectively. Relatively, the Fe3+ ions situated at (0001) planes facilitate the Fischer‐Tropsch synthesis (FTS) compared to that situated at {11‐20} planes. Due to the well dispersion and high fraction of (0001) basal facets, the α‐Fe2O3 nanodisks with middle size of 190 nm in thickness and 400 nm in diameter propose the high CO2 conversion and high hydrocarbon selectivity. Since more amount of (0001) basal facets are masked by the orientation aggregation along [0001] induced by the self‐magnetization, the least α‐Fe2O3 nanodisks provide a declined catalytic performance for CO2 hydrogenation. [ABSTRACT FROM AUTHOR]

Magnetite iron oxide nanoparticles synthesized using the co-precipitation methods were further functionalized with activated carbon. The magnetite-activated carbon nanoparticles were characterized by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and UV-Vis spectroscopy. X-ray diffraction and Fourier transform infrared confirmed the functionalization of the Fe3O4 nanoparticles with the activated carbon. The X-ray diffraction studies demonstrate that magnetite-activated carbon nanoparticles were indexed into the spinel cubic lattice with a lattice parameter of 0.833 nm and an average particle size of about 14 nm. Various parameters such as dislocation density, microstrain, and surface morphological studies were calculated. However, this work implicated the use of magnetite-activated carbon nanoparticles in antibacterial studies. Further, the antibacterial effect of magnetite-activated carbon nanoparticles was evaluated against three pathogenic bacteria, which showed that the nanoparticles have moderate antibacterial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Proteus mirabilis and Pseudomonas aureginosa) pathogenic bacterial strains in the presence of different magnetite-activated carbon nanoparticle concentrations at room temperature. [ABSTRACT FROM AUTHOR]

In this study, metal doping of iron oxide nanostructures grown by anodization is successfully achieved by the simple cost effective technique of electrochemical doping. Structural and morphological characterizations of all the samples are done using X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy in conjunction with field-emission scanning electron microscopy, respectively. A detailed analysis of the X-ray photoelectron spectra is done for all the samples to obtain the effect of aluminium doping on the multiplet peak positions of Fe 2p and different species of oxygen. Analysis of the valence band X-ray photoelectron spectra (VB XPS) reveals a displacement of 'valence band edge' towards higher energy on doping. The VB XPS coupled with optical data is used for evaluating the shift in the Fermi level towards the conduction band minimum, which indicates the formation of donor defect level on doping. The reduction in band gap from 1.96 to 1.72 eV and enhanced electrical conductivity on doping are observed to produce an improvement in the photo catalytic activity for aluminium-doped nanostructures compared to undoped. [ABSTRACT FROM AUTHOR]

Bio-inspired synthesis of iron oxide nanoparticles (FeONPs) has been carried out by eco-friendly, low cost, and facile method using an aqueous extract of Psidium guajava (PG) leaf as a potential reducing agent. The obtained FeONPs were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and energy-dispersive spectroscopy techniques. The surface plasmon resonance peak of FeONPs was found to be 310 nm. The FTIR spectra analysis indicates the presence of various functional groups in PG extract that are responsible for the biosynthesis of FeONPs. The XRD confirmed that FeONPs were indexed into the cubic spinel lattice structure. The SEM and TEM analysis confirmed the spherical morphology of FeONPs with particle size ranging from 1 to 6 nm. The superparamagnetic nature of the formulated FeONPs was determined using VSM. The FeONPs formulated inhibit the growth of six human pathogenic strains with strong activity chiefly against Escherichia coli and Staphylococcus aureus at low concentration when compared to other standard antibacterial drugs. It is noteworthy that the formulated FeONPs are efficient as an antibacterial agent. [ABSTRACT FROM AUTHOR]

Although the preparation of carbon composites has made great progress, the construction of systems comprising uniformly dispersed carbon as a framework to link active constituents still remains a challenge. Herein, a hierarchical Fe2O3/C composite was synthesized in a one-step biotemplating route, where agarose was firstly reacted with Fe3+ and Ca2+ ions, which resulted in a competitive interaction between these ions and the hydroxy groups, then partly calcined to achieve the final product that consisted of α-Fe2O3 nanoparticles embedded in highly dispersed carbon. The carbon within the composite acts as an efficient photoelectron transfer channel to improve conductivity during photocatalysis. The hierarchical Fe2O3/C composite exhibited a photodegradation rate constant (k) of 0.091 min-1, more than four times that of α-Fe2O3 (0.020 min-1). [ABSTRACT FROM AUTHOR]

In this work, dispersed nanoparticles of Fe2O3- and TiO2-reinforced linear saturated polyester resin nanocomposites were fabricated. Nanosized oxides of iron (III) and titanium (IV) and polyester resin were prepared throughout sol–gel deposition and polycondensation reactions, respectively. The incorporation of nanostructured metal oxides with polyester matrix was characterized. Molecular weight, structure, composition, morphology and electric property of composites were investigated by gel permeation chromatography, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and conductivity measurements. The obtained nanocomposites exhibit low crystallinity, high agglomeration and high conductivity due to the ionic cross-linking. Moreover, the biological activity of the fabricated nanocomposites was studied against selected strains of pathogenic bacteria and fungi. The biological effect of polyester nanocomposites has higher value than the free one. These nanocomposites will find potential sites in catalysis. [ABSTRACT FROM AUTHOR]

The characteristics of superfine powder composites formed in the interaction of nanosized silicon carbide with iron oxide in vacuum and argon at 1200 and 1400°C, respectively, are analyzed. Silicon carbide (β-SiC), iron silicide and carbide, silicon oxide, and silicon oxynitride are main components of the powder composites. The lattice parameter of SiC in the powder composites synthesized in the SiC–Fe2O3 system is determined. In the interaction in the SiC–Fe2O3 powder mixture in vacuum, secondary SiC is synthesized with a lattice parameter that corresponds to the standard parameter for cubic β-SiC. The interaction in an argon atmosphere is accompanied by the synthesis of secondary SiC with a decreased lattice parameter. The minimum lattice parameter (0.4336 nm) is 0.6% smaller than the standard parameter for cubic β-SiC. The morphology of the powder composite synthesized in the SiC–Fe2O3 system is studied. The average particle size of the powder composite decreases with increasing weight content of secondary SiC. [ABSTRACT FROM AUTHOR]

Connective tissue growth factor (CTGF) is a possible key determinant of progressive fibrosis. Nanotechnology has been considered as a potential tool for developing novel drug delivery systems for various diseases, including liver fibrosis. The present study aimed to investigate the potential antifibrotic activity of CTGF small interfering RNA (siRNA) mediated by polyethyleneimine (PEI)-functionalized magnetic iron oxide (Fe3O4) nanoparticles (NPs) in LX-2 cells. PEI-Fe3O4/siRNA complexes were synthesized to facilitate siRNA delivery and were transfected into LX-2 cells. Laser confocal microscopy was employed to investigate the cell uptake of PEI-Fe3O4/siRNA complexes. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting were used to verify the effect of gene silencing. The results showed that siRNA-loaded PEI-Fe3O4 exhibited low cytotoxicity. The transfection efficiency of PEI-Fe3O4/siRNA reached 73.8%, and RT-qPCR and western blotting demonstrated effective gene silencing. These results indicated that CTGF siRNA delivered by PEI-Fe3O4 NPs significantly reduces CTGF expression and collagen production in activated LX-2 cells, providing a basis for future in vivo studies. [ABSTRACT FROM AUTHOR]

Conversion of wastes to energy and other value-added products is considered as a suitable method towards energy security. Wastes from various sources are becoming potential feedstocks for energy production through different techniques. The economy and sustainability of these processes demand the use of low-cost catalysts. Red mud (RM) is one of the most abundantly produced industrial wastes from aluminum industries. Such a huge production of RM, its alkaline nature and the presence of a small quantity of radioactive elements make it an environmental liability. Out of various utilization methods, RM as a catalyst for different chemical processes has been very successful. Presence of many valuable metals in RM, in particular, Fe makes it a suitable catalyst for energy production through processes such as pyrolysis, hydrotreating, transesterification and H 2 production from biomass and other sources. This article critically reviews the advances in sustainable energy production through different processes mentioned above by RM based catalysts. Different characterization, activation and stability study of RM along with outcomes and mechanism of these processes are discussed. Furthermore, drawbacks associated with the low catalytic activity of RM and works that need to be carried out in the future for the improvement of its catalytic activity are discussed in detail. Image 101037 • Recent development in catalytic utilization of red mud for energy synthesis were explored. • Physical and chemical properties of RM were briefly explained. • Pyrolysis, hydrodeoxygenation, H 2 production and transesterification were discussed. • Catalytic activity and reaction pathways of energy synthesis were proposed. • Perspective to enhance the activity of RM for energy production were proposed. [ABSTRACT FROM AUTHOR]

The development of high performance magnetic nanomaterials has a good application prospect in wastewater treatment. Herein, Fe3O4/C nanocomposites was synthesized by eco‐friendly hydrolysis‐calcination method using potassium fulvic acid (FA−K) and FeCl3⋅6H2O as raw materials. The morphology of Fe3O4/C nanocomposites exhibited a loose pore structure with uniform size (a diameter ∼ 27 nm). The prepared Fe3O4/C nanocomposites possessed excellent dispersibility and magnetic properties in aqueous solution. The removal efficiency and maximum adsorption capacity of Fe3O4/C nanocomposites were 98% and 64.0 mg g−1, respectively. Moreover, it was confirmed that the adsorption mechanism of Cr(VI) contains electrostatic attraction and redox reaction. In this work, we provide a convenient means for manufacturing Fe3O4/C nanocomposites, and prove that FA−K is a cheap carbon source for manufacturing Fe3O4/C nanocomposites, which makes Fe3O4/C nanocomposites have potential application value in the effective adsorption of Cr(VI). [ABSTRACT FROM AUTHOR]

In this study, iron oxide, nickel oxide, and nickel-iron oxide nanostructured particles were produced by the hydrothermal method. X-ray diffraction (XRD) and SEM measurements were performed to investigate the physical properties of these nanostructured particles. According to the XRD results, the crystal properties of these particles were determined. From the SEM images, these particles understood to be nano-structured. The electrodes were examined for electrochemical properties by using these nanostructured particles. Electrochemical measurements of the produced electrodes were performed, and capacitance values and impedance spectra of the electrodes were determined. The specific capacitance values of the iron oxide, nickel-iron oxide, and nickel oxide nanostructured particles, respectively are 30 F/g, 55 F/g, and 67 F/g. Also, the photocatalytic activities of nanostructured particles were investigated. This examination methylene blue (MB) was used and made under a xenon lamp. In light of our findings, it was observed that high photocatalytic degradation rate. Nickel-iron oxide nanostructured particles, the degradation of MB were found to be about 87%. [ABSTRACT FROM AUTHOR]

Purpose: Acoustic coupling baths, nominally composed of degassed water, play important roles during transcranial focused ultrasound surgery. However, this large water bolus also degrades the quality of intraoperative magnetic resonance (MR) guidance imaging. In this study, we test the feasibility of using dilute, aqueous magnetite nanoparticle suspensions to suppress these image degradations while preserving acoustic compatibility. We examine the effects of these suspensions on metrics of image quality and acoustic compatibility for two types of transcranial focused ultrasound insonation regimes: low‐duty cycle histotripsy procedures and high‐duty cycle thermal ablation procedures. Methods: Magnetic resonance guidance imaging was used to monitor thermal ablations of in vitro gel targets using a coupling bath composed of various concentrations of aqueous, suspended, magnetite nanoparticles in a clinical transcranial transducer under stationary and flowing conditions. Thermal deposition was monitored using MR thermometry simultaneous to insonation. Then, using normal degassed water as a coupling bath, various concentrations of aqueous, suspended, magnetite nanoparticles were placed at the center of this same transducer and insonated using high‐duty cycle pulsing parameters. Passive cavitation detectors recorded cavitation emissions, which were then used to estimate the relative number of cavitation events per insonation (cavitation duty cycle) and the cavitation dose estimates of each nanoparticle concentration. Finally, the nanoparticle mixtures were exposed to low‐duty cycle, histotripsy pulses. Passive cavitation detectors monitored cavitation emissions, which were used to estimate cavitation threshold pressures. Results: The nanoparticles reduced the MR signal of the coupling bath by 90% in T2‐ and T2*‐weighted images and also removed almost all imaging artifacts caused by coupling bath motion. The coupling baths caused <5% changes in peak temperature change achieved during sonication, as observed via MR thermometry. At low duty cycle insonations, the nanoparticles decreased the cavitation threshold pressure by about 15 ± 7% in a manner uncorrelated with nanoparticle concentration. At high duty cycle insonations, the 0.5 cavitation duty cycle acoustic power threshold varied linearly with nanoparticle concentration. Conclusions: Dilute aqueous magnetite nanoparticle suspensions effectively reduced MR imaging artifacts caused by the acoustic coupling bath. They also attenuated acoustic power deposition by <5%. For low duty cycle insonation regimes, the nanoparticles decreased the cavitation threshold by 15 ± 7%. However, for high‐duty cycle regimes, the nanoparticles decreased the threshold for cavitation in proportion to nanoparticle concentration. [ABSTRACT FROM AUTHOR]

Using the sol-gel method we synthesized hematite (α − Fe2O3) nanoparticles in a silica matrix with 60 wt % of hematite. X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) spectra of the sample demonstrate the formation of the α − Fe2O3 phase and amorphous silica. A transmission electron microscopy (TEM) measurements show that the sample consists of two particle size distributions of the hematite nanoparticles with average sizes around 10 nm and 20 nm, respectively. Magnetic properties of hematite nanoparticles were measured using a superconducting quantum interference device (SQUID). Investigation of the magnetic properties of hematite nanoparticles showed a divergence between field-cooled (FC) and zero-field-cooled (ZFC) magnetization curves and two maxima. The ZFC magnetization curves displayed a maximum at around TB = 50 K (blocking temperature) and at TM = 83 K (the Morin transition). The hysteresis loop measured at 5 K was symmetric around the origin, with the values of coercivity, remanent and mass saturation magnetization HC10K ≈ 646 A/cm, (810 Oe), Mr10K = 1.34 emu/g and MS10K = 6.1 emu/g respectively. The absence of both coercivity (HC300K = 0) and remanent magnetization (Mr300K = 0) in M(H) curve at 300 K reveals super-paramagnetic behavior, which is desirable for application in biomedicine. The bimodal particle size distributions were used to describe observed magnetic properties of hematite nanoparticles. The size distribution directly influences the magnetic properties of the sample. [ABSTRACT FROM AUTHOR]

ReaxFF molecular dynamics simulation has been employed to investigate the iron oxide-catalyzed supercritical water gasification (SCWG) of naphthalene (NAP), a common component of refractory polycyclic aromatic hydrocarbons. Simulation results showed that synergistic effects between SCW and iron oxide catalyst enormously promoted the degradation of NAP and the production of H 2 and CO. During the gasification process, SCW served not only as H source for H 2 generation but also as O source for CO generation and lattice oxygen recompense, while the major roles of iron oxide catalyst were to provide lattice oxygen with high hydrogen-abstraction ability, catalyze SCW to produce more active species, and weaken the C–C bonds. The effects of different parameters were subsequently revealed: increasing the use of H 2 O molecules raised H 2 and CO yields along with the lattice oxygen supplement but slowed the rate of CO generation, high hydrogen recovery was achieved at high NAP concentration accompanied by a low carbon gasification efficiency. Our simulated results further demonstrated that the deactivation of iron oxide catalyst was caused by carbon deposition, lattice oxygen exhaustion and iron loss. SCW media effectively inhibited the iron loss, while calcination in O 2 environment could successfully regenerate the iron oxide catalyst by cleaning up the carbon deposition and replenishing the lattice oxygen. Image 1 • SCW served not only as H source but also as O source. • Iron oxide provided lattice oxygen, catalyze SCW and C–C breaking. • Carbon deposition, lattice oxygen and iron loss caused catalyst deactivation. • Catalyst regeneration mechanism in O 2 environment was also revealed. [ABSTRACT FROM AUTHOR]

Development of simultaneous bacteria detection and eradication with simple, rapid, and reusable material is important in addressing bacterial contamination issues. In this study, we utilized the expression of alkaline phosphatase (ALP) from bacteria to design fluorescence ON/OFF system for bacteria detection, also using metal oxide nanoparticle for obtaining antibacterial activity and recyclability. The fluorescent-based biosensor with antibacterial activity was prepared by intercalating ALP-sensitive polymer dot (PD) containing β-cyclodextrin (β-CD) onto montmorillonite (MMT) as loading matrix via ionic exchange reaction, followed by immobilization of magnetic iron oxide (Fe 3 O 4) and NIR-responsive cesium tungsten oxide (CsWO 3). The PD-βCD-MMT/Fe 3 O 4 –CsWO 3 nanocomposite exhibited strong fluorescence intensity, which was quenched in the presence of bacterial ALP (0–1000 U/L) due to hydrolysis of p -nitrophenyl phosphate (NPP) into p -nitrophenol (NP) in the hydrophobic site of β-CD. Furthermore, the nanocomposite could detect both gram-negative Escherichia coli and gram-positive Staphylococcus aureus in the range of 101–107 CFU/mL (LOD 5.09 and 4.62 CFU/mL, respectively), and showed high antibacterial activity against bacteria by generating photothermal heat under 5 min NIR irradiation, causing damage to bacterial cells. This material also demonstrated recyclability via magnetic field exposure due to the presence of Fe 3 O 4. In addition, the fluorescence can be recovered following pH shock and re-conjugation of β-CD molecules. After 4 cycles, nanocomposite still showed stable photothermal effects and fluorescence-based bacteria detection. Thus, this reusable material offers promising approach for simultaneous bacteria detection and killing, which is simple, rapid, and effective. Image 1 • Reusable material was designed for fluorometric sensing and photothermolysis of bacteria. • The fluorescence ON/OFF sensing system was depended on the bacterial ALP activity. • The LOD of fluorescence-based bacteria detection showed below 101 CFU/mL. • Hybrid nanocomposite showed ±100% killing efficiency after 5 min NIR irradiation. • Antibacterial/bacteria sensing showed excellent performance even after 4 cycles. [ABSTRACT FROM AUTHOR]

In this present study, we have shown dopamine acts as very good agent in killing cancer cells with very high rate. We have used silica coated iron oxide magnetic particles as dopamine drug delivery agent. We have synthesized iron oxide (Fe3O4) magnetic nanoparticles (MNPs), and coated it with silicon dioxide (SiO2), then loaded it with dopamine (DA) which has been used here as anticancer drug. Here a significant improvement was found in case of drug release under acidic pH than normal blood pH. The MNPs are characterized using X‐ray diffraction (XRD), Energy Dispersive Analysis of X‐rays (EDAX), Fourier transform infrared (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM), Selected Area Electron Diffraction (SAED) and vibrating sample magnetometer (VSM) to confirm its structural, morphological and magnetic properties. Particles after characterization were involved in investigation of DA drug release by altering pH for better treatment of cancer. The results are very important and promising. [ABSTRACT FROM AUTHOR]

Local structure and the photo-Fenton reactivity of iron-containing glasses and glass-ceramics prepared from Japanese domestic waste slag were investigated. The largest rate constant (k) of (2.8 ± 0.08) × 10−2 min−1 was recorded for the methylene blue degradation test by using H2O2 with a heat-treated 'model slag'. The 57Fe Mössbauer spectrum was composed of a paramagnetic doublet with isomer shift of 0.18 ± 0.01 mm s−1 attributed to distorted FeIIIO4 tetrahedra. These results indicate that the paramagnetic Fe3+ provided strong photo-Fenton catalytic ability, and that waste slag can thus be recycled as an effective visible-light activated photocatalyst. [ABSTRACT FROM AUTHOR]

In this study, iron oxide, nickel oxide, and nickel-iron oxide nanostructured particles were produced by the hydrothermal method. X-ray diffraction (XRD) and SEM measurements were performed to investigate the physical properties of these nanostructured particles. According to the XRD results, the crystal properties of these particles were determined. From the SEM images, these particles understood to be nano-structured. The electrodes were examined for electrochemical properties by using these nanostructured particles. Electrochemical measurements of the produced electrodes were performed, and capacitance values and impedance spectra of the electrodes were determined. The specific capacitance values of the iron oxide, nickel-iron oxide, and nickel oxide nanostructured particles, respectively are 30 F/g, 55 F/g, and 67 F/g. Also, the photocatalytic activities of nanostructured particles were investigated. This examination methylene blue (MB) was used and made under a xenon lamp. In light of our findings, it was observed that high photocatalytic degradation rate. Nickel-iron oxide nanostructured particles, the degradation of MB were found to be about 87%. [ABSTRACT FROM AUTHOR]

In this research, various weight loadings of Fe (3%, 5%, 7%, and 10%) supported on mesoporous titania nanoparticles (MTNs) were prepared using in-situ electrolysis before being characterised using X-ray diffraction, Fourier transform infrared, surface area analysis, UV–vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The performance of the Fe–MTN catalysts was investigated under visible light illumination based on the photocatalytic degradation of 2-chlorophenol. Among the catalysts, 3 wt% Fe–MTN demonstrated the highest degradation (99%), followed by 10, 7, and 5 wt% with degradations of 71%, 58%, and 54%, respectively. It has been indicated that the addition of Fe into MTN has enhanced the photocatalytic performance by lowering the catalyst's band gap to improve its efficiency under visible light. The kinetic study has shown that the reaction followed a pseudo-first-order kinetic model and the catalyst remained stable with a slight decrease after five cycles of degradation. Furthermore, the catalyst illustrated a positive performance in photocatalytic degradation of phenolic derivatives. Image 1 • Fe doped onto mesoporous titania nanoparticles reduced the band gap energy. • The lowest band gap energy gave the highest degradation. • 3 wt% gave 99% degradation of 2-chlorophenol under visible light irradiation. [ABSTRACT FROM AUTHOR]

• A multiscale modeling framework for fluidized bed reactors is presented. • Chemical looping reforming reactor employing iron oxide nanoparticles is modelled. • Kinetic Monte Carlo simulations provide rates of surface chemistry. • Intra-particle transport model handles competing diffusion and chemical reactions. • Reactive multiphase flow is modeled by fluid-particle flow model. A multiscale modeling framework is described and applied to the reactivity of iron oxide nanoparticles in a chemical looping reforming (CLR) reactor. At the atomic scale/nanoscale, we have performed kinetic Monte Carlo modeling, guided by Density Functional Theory calculations, on the detailed kinetics of the CH 4 conversion to products as a function of temperature. These results have been post-processed for use in macroscopic models with the goal to integrate process information with materials information. Two levels of macroscopic models have been used to evaluate the performance of the nanoparticles in their final application: (1) a pore-unresolved intra-particle transport model that accounts for limitations via an effective diffusivity and an effectiveness factor, and (2) a fluid-particle multiphase flow model that allows the study of the consequences of clustering and intra-particle transport on overall reactor performance. This modeling approach ultimately leads to better descriptors of material performance that can be used in future materials screening activities. [ABSTRACT FROM AUTHOR]

Modification in burn rate of composite solid propellant has become a necessity of a mission. Burn rate can be modified by various mean viz. (i) tailoring the ammonium perchlorate (AP) particle size, (ii) use of nano-sized particles and (iii) incorporating burn rate modifiers. Literature discusses about various burn rate modifiers. Out of these, Iron oxide (Fe 2 O 3)/IO is the well known burn rate enhancer. Here a systematic study was carried out by undertaking experiments at varying levels of IO in composite propellant compositions. This paper attempts to understand the effect of IO content and its specific surface area on burn rate characteristics of composite propellant. This study also attempts to find out alternative to ultrafine AP and nano burn rate enhancer to account for high burning rate of composite propellant along with reduced slurry viscosity and longer pot life for easy processing. As ultrafine AP and nano burn rate enhancers have their limitations in terms of (i) high end of mix (EOM) propellant slurry viscosity, (ii) difficulty in propellant processing, (iii) less reproducibility in attaining the similar particle size in each batch results in lesser repeatability in ballistic properties of propellant, (iv) hazards involved in size reduction, (v) limitations in handling, storage and shelf life and also (vi) the higher cost of nano particles. Therefore an extensive experimental study was performed to achieve this objective. In this study, we incorporated two different grades of IO(A) and IO (B) in composite propellant compositions. The average particle size of both grades of IO i.e., A and B are of ∼1 µm. But the specific surface area of IO (B) was about 15 times more than IO (A). The large difference in specific surface area of both IO was due to difference in the manufacturing process. During the manufacturing of IO, the calcination temperature plays very important role in deciding the specific surface area. High specific surface area is obtained if calcination is done at very high temperature (>1773 K). Burning rate measurements were carried out. It was observed that IO is a good burn rate enhancer. Initially, the burn rate increased with the increase in % of IO. But after that only a marginal enhancement in burn rate was observed. It was noticed that though both grades of IO are effective burn rate enhancer but IO(B) was 30% more effective than IO(A). Also it was found that IO(B) is an alternative to ultrafine AP and nano burn rate modifiers. This IO(B) was further used to develop the propellant compositions with high burn rate without incorporating ultrafine AP and nano particles. Viscosity measurement and mechanical properties determination revealed that both the IOs did not much adversely alter the processing characteristics and mechanical properties of propellant. [ABSTRACT FROM AUTHOR]

Amorphous iron(III) oxide thin films have been prepared by vacuum ultraviolet (VUV) photochemically initiated oxidative conversion of [Fe(O t Bu) 3 ] 2 at ambient temperature and pressure. The decomposition process and kinetics for conversion of [Fe(O t Bu) 3 ] 2 precursor film thicknesses of 109–330 nm to much thinner and crack-free iron(III) oxide films (38–54 nm) were investigated. Due to the film shrinkage, higher densities as compared to hydrolysis (3.15 vs. 2.6 g cm−3) could be achieved. Mechanistic insight by DFT calculations and FTIR spectroscopy suggests the formation of intermediate Fe(CO 2)-ring structures throughout the photochemical conversion process. Resulting iron(III) oxide layers were almost carbon free and exhibiting high transparency in the visible range. The proposed photochemical synthesis pathway represents an attractive route in achieving a dense metal oxide coating at low temperatures, e.g. for coating onto thermally sensitive substrates. Unlabelled Image • Iron(III)oxide thin films were prepared by photochemically initiated conversion of [Fe(O t Bu) 3 ] 2 at ambient conditions • Mechanistic insight into the photochemical conversion process was given by infrared spectroscopy and DFT calculations • Photochemical conversion resulted in thin film densification • Amorphous iron(III) oxide thin films showed higher UV-vis transparency and band gaps as compared to crystalline materials [ABSTRACT FROM AUTHOR]

We here couple Nb 2 O 5 with Fe 2 O 3 to form visible-light active heterojunctions. The formed heterojunctions are responsive to visible light, and more importantly, photoactive for the mineralization of refractory organic compounds upon exposure to visible light. The sensitizer, Fe 2 O 3 , is found to govern the photocatalytic activity of the heterojunction. Therefore, the local structure of the sensitizer is investigated in-depth with X-ray absorption spectroscopy, including X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). Results show that the local structure of Fe 2 O 3 is generally insensitive to the Fe 2 O 3 loading amount, as confirmed by EXAFS. The lengths of the Fe–O coordination and Fe–Fe coordination in the heterojunctions are 1.93 and 2.92 Å, respectively, which are shorter than those in bulk Fe 2 O 3. At a Fe 2 O 3 loading amount that is higher than the optimum value, trace amounts of isolated Fe 2 O 3 and bulk Fe 2 O 3 are likely formed at the heterojunction. This is unfavorable for electron-hole separation, and hence, detrimental to the photocatalytic activity. Image 1 • Heterojunctions composed of Nb 2 O 5 as host and Fe 2 O 3 as sensitizer are prepared. • The heterojunctions are visible light active for photomineralization of organics. • Local structure of the sensitizer, Fe 2 O 3 , is examined in-depth by XANES and EXAFS. • Visible light photoactivity of the heterojunctions is proposed based on light-induced IR. [ABSTRACT FROM AUTHOR]

Purpose: Nowadays, cancer is one of the most important causes of morbidity and mortality in the world. The ideal aim of radiotherapy is delivering a lethal radiation dose to tumor cells while minimizing radiation exposure to healthy tissues around the tumor. One way to increase the dose in the tumor cells is the use of high-atomic number nanoparticles as radiosensitizer agents in these cells. The aim of this in vitro study was investigating the radiosensitization enhancement potential of the dextran-coated iron oxide nanoparticles (IONPs) on HeLa and MCF-7 cell lines in irradiations with high-energy electron beams.Materials and Methods: In this in vitro study, the cytotoxicity level of dextran-coated IONPs at different concentrations (10, 40, and 80 μg/ml) was assessed on HeLa and MCF-7 cell lines. To evaluate the radiosensitivity effect, the nanoparticles were incubated with the cells at different concentrations for 24 h and afterward irradiated with different doses (0, 2, 4, 6, and 8 Gy) of 6 and 12 MeV electron beams. The cells survival fractions were obtained by the methylthiazoletetrazolium assay.Results: Toxicity results of the nanoparticles at 10 and 40 μg/ml concentrations showed no significant cytotoxicity effect. The cells survival rates in groups receiving radiation in the absence and presence of IONPs showed a significant difference. The radiosensitivity enhancement induced by the nanoparticles in MCF-7 cell line was more than it in HeLa cell line. The average of radiosensitization enhancement factor at 10, 40, and 80 μg/ml concentrations and under 6 MeV irradiations obtained as 1.13, 1.19, 1.25, and 1.26, 1.28, 1.29 for HeLa, and MCF-7 cells, respectively. When 12 MeV electron beams were carried out, the values of 1.17, 1.26, 1.32, and 1.29, 1.32, 1.35 were obtained for the cells at the mentioned concentrations, respectively. Furthermore, the significant differences were observed in radiosensitization enhancement between 6 and 12 MeV electron beams irradiations.Conclusion: Use of dextran-coated IONPs can increase radiosensitivity and consequently at a given absorbed dose more cell killing will occur in cancerous cells. In other words, these nanoparticles can improve the efficiency of electron therapy. [ABSTRACT FROM AUTHOR]

In this paper, we present a simple and inexpensive method for synthesizing conductive polyaniline and magnetite composites. Firstly, the magnetite was synthesized by precipitation in basic medium from FeCl3, and the Rietveld refinement confirmed the spinel structure. Different amounts of magnetite were used in the in situ synthesis of Pani- Fe3O4 composites to determine the influence, resulting in the following materials: Pani-Fe3O4 (1) with 0.06 g and Pani-Fe3O4 (2) with 0.24 g. The x-ray diffractogram demonstrates that interaction occurs between the polyaniline chains and the magnetite particles in the composites. Infrared and ultraviolet-visible vibrational spectra indicate that the composites are in the state of oxidation polyaniline salt emerald, which is the conductive form of greatest interest. Scanning electron microscopy images show that composites have particles with no definite geometry in the form of clusters, and the best homogeneity was achieved in the composite with the highest amount of magnetite. Evidence indicates that Pani-Fe3O4 (2) material with 0.24 g of magnetite to be incorporated in polyaniline synthesis may have more technologically interesting properties, but further studies will be needed for confirmation. [ABSTRACT FROM AUTHOR]