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With the continuous advancement of carbon peaking and carbon neutrality goals worldwide, the concept of "hydrogen replacing carbon" is gradually becoming the mainstream for the future development of the steel industry. It plays a crucial role in achieving carbon reduction at the source and breaking away from dependence on fossil fuels. Based on this, this study focuses on the kinetic research of non-isothermal reduction of different iron-containing raw materials under a hydrogen atmosphere. The TG curve and DTG curve in the temperature range from room temperature to 1223K were obtained by thermogravimetric analysis. The research reveals that the hydrogen reduction of iron-containing raw materials can be divided into three stages. In the Stage Ⅰ, hydrogen exhibits strong reduction ability towards HM iron concentrate powder and BY iron concentrate powder, with apparent activation energies of 19.997 kJ/mol and 23.863 kJ/mol, respectively. In the Stage Ⅲ, the presence of Wüstite and MgFe 2 O 3 in HM iron concentrate powder and BY iron concentrate powder hinders the reduction rate. Throughout the reaction stages, the hydrogen reduction of HF ore powder and PB ore powder requires overcoming relatively small reaction barriers, with apparent activation energies of 62.274 kJ/mol and 64.568 kJ/mol, respectively. This analysis provides a theoretical basis for the effective hydrogen reduction of iron-containing raw materials. [Display omitted] • Exploring the reduction behavior of iron-containing raw materials during heating using non-isothermal methods. • Classifying reaction regions based on the variations in TG and DTG curve profiles. • It is proposed that in the Stage Ⅲ of the reaction, the formation of MgFe 2 O 4 leads to an increase in activation energy. • In proposing a deceleration in the Stage Ⅲ of the reaction, two factors may be considered. [ABSTRACT FROM AUTHOR]

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

Biogas conversion is a renewable alternative for producing hydrogen. In this work, dry reforming of simulated biogas was performed in a 1 kW th continuous chemical looping reforming (CLR) unit in which the oxygen required for the partial oxidation of biogas to CO and H 2 is supplied by an oxygen carrier. The performance of two different oxygen carriers (an iron oxide-based residue and a synthetic material based on an iron-manganese mixed oxide) was evaluated. The residue was capable of performing the dry reforming of biogas to a larger extent than the synthetic oxygen carrier. To enhance hydrogen yield, NiO addition was also considered with both materials. The presence of NiO increased methane conversion and H 2 selectivity for both oxygen carriers. A value of approximately 2.6 mol H 2 /mol CH 4 was achieved with both materials with the presence of only 2.7 wt% NiO in the bed. • Dry-CLR of biogas was evaluated in a 0.5 kW th chemical looping unit. • Two Fe-based oxygen carriers tested: one residue and one iron-manganese mixed oxide. • The residue performed the dry reforming of biogas in a larger extent. • NiO addition to both oxygen carriers increased methane conversion and H 2 selectivity. • Yield of 2.6 mol H 2 /molCH 4 with both materials with 2.7 wt% NiO in the bed. [ABSTRACT FROM AUTHOR]

The use of thermite to aid spacecraft demise during atmospheric re-entry has been investigated in the ESA-TRP SPADEXO project. An experimental campaign in DLR's L2K arc-heated wind tunnel facility was dedicated to explore the Thermite-for-Demise concept. Steel mock-ups of a ball bearing unit, partially filled with thermite, were placed in L2K. The breadboards were then exposed to an air flux simulating the typical conditions that characterize spacecraft re-entry. In this paper, the key results of the tests are presented. The dispersion of a mechanically activated fraction of thermite proved to be effective in controlling the overall charge ignition temperature. Thermite-induced demise was experimentally verified in the wind tunnel. The SCARAB software was extended and used to rebuild the retrieved thermal data. The results of the simulations were in good agreement in both predicting the ignition timing and the effects of the thermite charge on the sample. • Thermite-induced demise was verified in hypersonic wind tunnel conditions. • Mechanical activation can tune thermite passive ignition in space-like environment. • Numerical models can describe and foresee thermite-induced demise. [ABSTRACT FROM AUTHOR]

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

The phase equilibria of the ZnO-"FeO 1..5 ", ZnO-"FeO 1.5 "-SiO 2 , PbO–ZnO-"FeO 1.5 " and PbO–ZnO-"FeO 1.5 "-SiO 2 slag systems in equilibrium with air or metallic lead/iron were studied as part of the investigation of the 19-component PbO–ZnO–Cu 2 O–FeO–Fe 2 O 3 –CaO–SiO 2 –Al 2 O 3 –MgO–S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co as minor elements) slag/matte/metal/speiss/gas system, supporting the operation/development of existing and emerging pyrometallurgical processes. In the experimental part of the study, samples underwent high temperature equilibration followed by quenching, and the direct measurement of the lead, zinc, iron and silicon concentrations in the liquid slag, solid oxide, and metal phases by electron probe microanalysis (EPMA). The a) massicot (PbO), b) spinel ((Zn, Fe)Fe 2 O 4), c) zincite ((Zn,Fe)O 1+x , 2 polymorphs), d) lead ferrite (Pb 2+x Fe 2 O 5+x), e) plumboferrite (Pb 4 Fe 22-x Zn x O 37), f) magnetoplumbite (Pb(Fe 2 O 3 ,PbFeO 2 ,PbZnO 2)Fe 10 O 16), and g) W-ferrite (PbZn 2-x Fe 16+x O 27) primary phase fields of the PbO–ZnO-"FeO 1.5 " system in equilibrium with air were studied between 780 and 1300 °C. The ZnO-"FeO 1.5 ", ZnO-"FeO 1.5 "-SiO 2 and PbO–ZnO-"FeO 1.5 "-SiO 2 systems in equilibrium with air were studied up to 1745 °C, significantly improving the availability of information on the composition range of the high- and low-Fe zincite ((Zn,Fe)O 1+x) phases, and on the liquid slag composition at the boundaries of their primary phase fields. Lastly, the solubilities of iron in larsenite (Pb(Zn,Fe)SiO 4) and melilite (Pb 2 (Zn,Fe)Si 2 O 7) in equilibrium with air or metal were studied between 700 and 800 °C. The newly obtained and existing experimental data were used to develop a self-consistent set of thermodynamic parameters describing all phases in the system using the FactSage computer package. [ABSTRACT FROM AUTHOR]

Nickel isotope fractionation during continental weathering is not well constrained due to the limited research on Ni isotopes during weathering of mafic rocks such as basalt. This study investigated two weathering profiles (strongly and extremely weathered) derived on basalts in tropical China. The strongly weathered profile was dominated by kaolinite and divided into three layers with depth (soil, saprolite and rock). The extremely weathered profile was mainly composed of Fe- and Al-(oxyhydr)oxides and kaolinite, and included a special ferricrust layer, iron-rich duricrust with ferruginous nodules, between the soil and saprolite. We analysed the Ni speciation (e.g. Fe-oxide phases and residual phase) and isotopic composition of soil, ferricrust, saprolite, rock and water samples in the weathering profiles. Pore water and groundwater were collected underlying the extremely weathered profile, and the size-distribution of particulate Ni (1 kDa–450 nm) in water samples was analysed. Nickel in both profiles was mainly hosted in the residual phase (>71% of total Ni) which included primarily secondary silicates and Al-(oxyhydr)oxides. Weathering intensity controlled the mineral compositions and physico-chemical properties of the weathering profiles as well as Ni isotopic variations. Nickel redistribution (∼30%) and isotope fractionation (Δ60Ni regolith-rock = −0.08‰ to 0.07‰) were slight in the strongly weathered profile due to the dominance of secondary silicates in Ni speciation. For the extremely weathered profile, significant Ni depletion (∼67%) and isotope fractionation (Δ60Ni regolith-rock = −0.25‰ to 0.32‰) were related to the transformation of secondary silicates into Fe- and Al-(oxyhydr)oxides during lateritic weathering. The positive correlation of δ60Ni and Ni concentrations indicated that Ni isotope fractionation was controlled by Ni adsorption and incorporation of secondary minerals. In the lower saprolite, the calculated isotope fractionation between Ni remaining in the profile and leaching to the solution (Δ60Ni solid-solution = −0.47‰) indicated that Ni isotope fractionation was mainly controlled by the preferential adsorption of isotopically light Ni on Fe- and Al-(oxyhydr)oxides. However, in the soil and ferricrust, acidic pH (∼5.0) might reduce Δ60Ni solid-solution to −0.28‰ by releasing the isotopically light adsorbed Ni, leading to the predominance of incorporated Ni in Fe- and Al-(oxyhydr)oxides. Specifically, the highest δ60Ni value (0.27 ± 0.05‰) and Ni concentration in the upper saprolite indicated that the isotopically heavy Ni leached from the soil and ferricrust was scavenged by precipitating secondary silicates. Finally, the estimated isotopic composition of Ni leached from the extremely weathered profile (δ60Ni output = 0.02 ± 0.15‰) was close to that of pore water (0.06 ± 0.01‰) where Ni was mainly present in the particulate phase. Compared with groundwater (δ60Ni = 0.33 ± 0.04‰) dominated by dissolved Ni, Ni output from the profile likely consisted of isotopically heavy dissolved Ni and light particulate Ni. Overall, this study provides a comprehensive understanding of Ni redistribution and speciation in basalt weathering profiles, highlighting the significance of weathering intensity in controlling Ni isotope fractionation and its implications for Ni outputs from continental weathering. [ABSTRACT FROM AUTHOR]

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

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

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

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

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

With technological and economic developments, the amount of domestic and industrial solid waste is gradually increasing. It is important to investigate the methods that will ensure the disposal of waste in the roof tile industry, which is one of these solid wastes. In this study, the pigment effect of waste roof tile in ceramic glaze formulations was investigated. Waste roof tiles were added at the rate of 5-10-15-20% to the ceramic glaze formulations. Two different grinding times, 10 min and 45 min, were applied to the formed formulations, and their effects were compared. The chemical analysis of the waste tile used in the formulations by X-ray Fluorescence (XRF), the effect on the glaze surface hardness by the Vickers hardness method, and the surface properties and characterizations of the obtained samples were examined by Scanning Electron Microscopy (SEM). It is foreseen that the roof tile waste will contribute to the usability and economic/environmental aspects of the ceramic industry. [ABSTRACT FROM AUTHOR]

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

The recovery and extraction of uranium is vital to ensure sustainability of nuclear energy production and safety of environment. Herein, we report a facile method to synthesise diglycolamic-acid-functionalized iron oxide@titanium dioxide magnetic nanocomposite (Fe 3 O 4 @TiO 2 -DGA) as an efficient adsorbent for effective removal of uranium (VI) from aqueous medium. Fe 3 O 4 @TiO 2 -DGA showed high uranium adsorption performance, with a sorption capacity of 371.8 mg g–1 at pH 6.0 and reached equilibrium within 40 min. The adsorption isotherm fits well with Langmuir and the kinetics follows pseudo-second-order model, respectively. The plausible mechanism of U(VI) adsorption involves the electrostatic interaction between the diglycolamic acid and hydrolysed uranium species. Thermodynamic studies revealed that the adsorption was spontaneous and exothermic in nature. The U(VI)-loaded Fe 3 O 4 @TiO 2 -DGA could be conveniently separated from aqueous solutions using an external magnet, and further U(VI) is desorbed by adding dil. HCl. Fe 3 O 4 @TiO 2 -DGA showed exceptional selectivity for U(VI) in presence of various coexisting metal ions and it can be effectively reused for more than 5 times with negligible change in sorption capacity. Thus, Fe 3 O 4 @TiO 2 -DGA can be considered as an effective and potential sorbent for U(VI) remediation from aqueous solutions. [Display omitted] • Fe 3 O 4 @TiO 2 -DGA is synthesized through facile method for enhanced adsorptive removal of U(VI) from aqueous solutions. • Fe 3 O 4 @TiO 2 -DGA can selectively extract U(VI) with a maximum adsorption capacity (q max) of 371.8 mg g−1 at pH 6.0. • Equilibrium adsorption is achieved with minimum contact time of 40 min • The nanocomposite exhibited significant reusability even after several adsorption cycles. [ABSTRACT FROM AUTHOR]

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

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

Baicalin obtained from natural plants has essential medical value, so the development of accurate and sensitive quantitative methods for it is one of the most important tasks. Here, the FeO X /Fe@porous carbon composite (Fe@C) was synthesized by solvothermal method and carbonized at different temperatures under an N 2 atmosphere, and an electrochemical sensor designed based on this material was applied to the accurate and rapid determination of baicalin. According to the results of physical and electrochemical characterization, Fe@C at different pyrolysis temperatures exhibited different morphologies and different electrochemical properties, while the Fe@C pyrolyzed at 800 °C had the optimum performance. Compared with NH 2 -MIL-88B, the pyrolysis greatly reduces the charge transfer internal resistance of the material and has a larger porosity and specific surface area, resulting in an eminent electrochemical signal for the detection of baicalin. The sensor Fe@C-800/GCE not only has a linear range of 4 nM–700 nM with a low limit of detection of 1.16 nM for the detection of baicalin, but also has outstanding repeatability, anti-interference and stability for the detection of baicalin in several natural plant samples and herbal medicines samples. This work presents several pyrolytic NH 2 -MIL-88B as electrochemical sensors for the detection of baicalin for the first time, providing a novel idea for the application of MOFs derivatives in environmental analysis. [Display omitted] • Pyrolyzed NH 2 -MIL-88B has large specific surface area and high catalytic activity. • The optimal pyrolysis temperature and catalytic properties of Fe@C has been found. • The baicalin sensor based on Fe@C has been constructed for the first time. • The sensor has high sensitivity and wide linear range for detection of baicalin. • The sensor has shown excellent performance in analysis of actual samples. [ABSTRACT FROM AUTHOR]

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

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

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

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

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

In this study, 15 % w/w polyvinylidene fluoride (PVDF)–Fe3O4 nanoparticle (NP) nanocomposite scaffolds were prepared using coaxial electrospinning with a high-speed conductive rotating collector to obtain aligned fibers. The effects of varying the Fe 3 O 4 NP size (6, 9, and 14 nm in diameter) on the fiber morphology, mechanical response, and piezoelectric phase content were investigated. In situ X-ray diffraction measurements during heating-cooling and tensile tests were carried out using synchrotron radiation to study the charge in the β-phase content and polymer chain orientation under different conditions. At zero strain, the presence of smaller NPs seems to impede the β-phase crystallization in PVDF. However, heating-cooling cycles revealed that the NPs acted as nucleation agents, promoting a higher β-phase content after cooling compared to pure PVDF. The mechanical response showed that nanocomposites with smaller NPs exhibited higher stiffness. While the initial degree of polymer chain orientation was higher in the nanocomposites, the presence of NPs hindered the α-to-β phase transformation and chain alignment under tensile deformation compared to pure PVDF. This study highlights the complex interplay among NP size, β-phase formation, mechanical properties, and chain orientation in PVDF-Fe 3 O 4 nanocomposites, providing insights into tailoring their piezoelectric performance for various applications. Graphical abstract: Comparison of two electrospun fibers: pure PVDF and PVDF + Fe₃O₄ nanoparticles. The pure PVDF fibers are thicker than the nanocomposite fiber, suggesting that pure PVDF fibers have a greater margin for deformation and alignment of polymer chains within the fiber structure. In contrast, the nanocomposite fibers, incorporating Fe₃O₄ nanoparticles, show reduced thickness, indicating less margin for deformation and orientation of polymer chains. However, both types of fibers exhibit a limit to polymer chain orientation before breakage occurs. [Display omitted] • We analyzed the microstructure at different length scales. We investigated the distribution of NPs as a function of their size. • A detailed description of the crystalline structure as a function of the NP size is provided under different conditions (mechanical and thermal loading). • This analysis provides details on the interaction at the NP length scale and the distribution of crystalline phases in the presence of the surrounding iron oxide NPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pyrite significantly boosts R m and reduces λ in biohydrogen production at 20 °C. • Pyrite not only accelerates EPS secretion but also increases its overall yield. • Pyrite enhances the secretion of flavins and improves e- transfer during fermentation. • More negative (ΔG°)' values of the rate-limited steps can be achieved with pyrite. This study investigates the efficacy of pyrite in enhancing biohydrogen production from xylose at low temperature (20 °C). Higher hydrogen yield rates (R m) and reduced lag time (λ) were achieved across initial xylose concentrations ranging from 2-10 g/L. At an optimal xylose concentration of 5 g/L, pyrite reduced λ by 2.5 h and increased R m from 1.3 to 2.7 mL h−1. These improvements are attributed to pyrite's ability to enhance the secretion of extracellular polymeric substance and flavins, facilitate NADH and NAD+ generation and transition, and favor biohydrogen production. Thermodynamic analyses and Gibbs free energy calculations further elucidated pyrite's role in the full reaction process and rate-limiting steps at low temperature. This study offers valuable insights into improving the efficiency of biohydrogen production at low temperature, with significant implications for energy conservation. [ABSTRACT FROM AUTHOR]

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

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

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

The catalytic performance of modified hydroxyapatite nanoparticles, Ca 10-x Fe x-y W y (PO 4) 6 (OH) 2 , was applied for the degradation of methylene blue (MB), fast green FCF (FG) and norfloxacin (NOR). XPS analysis pointed to the successful partial replacement of Ca by Fe. Under photo-electro-Fenton process, the catalyst Ca 4 FeII 1·92 W 0·08 FeIII 4 (PO 4) 6 (OH) 2 was combined with UVC radiation and electrogenerated H 2 O 2 in a Printex L6 carbon-based gas diffusion electrode. The application of only 10 mA cm−2 resulted in 100% discoloration of MB and FG dyes in 50 min of treatment at pH 2.5, 7.0 and 9.0. The proposed treatment mechanism yielded maximum TOC removal of ∼80% and high mineralization current efficiency of ∼64%. Complete degradation of NOR was obtained in 40 min, and high mineralization of ∼86% was recorded after 240 min of treatment. Responses obtained from LC-ESI-MS/MS are in line with the theoretical Fukui indices and the ECOSAR data. The study enabled us to predict the main degradation route and the acute and chronic toxicity of the by-products formed during the contaminants degradation. [Display omitted] • New modified hydroxyapatite nanoparticles as catalysts to produce.●OH in the MB, FG dyes and NOR degradation; • High recyclability of the heterogeneous catalyst was verified due to magnetic properties. • MB, FG dyes and NOR reached high degradation rate by Photo-Electro-Fenton process using GDE. • Acute and chronic theoretical toxicological was evaluated to NOR. • The by-product identification study resulted in low toxicity compounds. [ABSTRACT FROM AUTHOR]

Breakaway corrosion of Fe-base alloys remains a challenge in applications operated in harsh conditions. The material lifetimes are often determined by the corrosion propagation after breakaway. Nevertheless, detailed microstructural studies, linking the protective properties of the Fe-rich oxides formed after breakaway, are scarce. This study utilizes APT to investigate the Fe-rich oxides formed after breakaway, i.e., the secondary corrosion protection, of four Fe-based model alloys chosen to exhibit good and poor secondary protection at 600 °C. The APT investigation shows that the inward-growing scale is heterogeneous at the nanometer scale and that Fe-enriched regions form on the poorly protective oxides. [Display omitted] • Fe-rich oxides formed after breakaway of FeCrNi and FeCrAl(Si) alloys are studied. • Higher Si or Ni contents significantly reduce growth rates of Fe-rich oxide scales. • APT-measurements elucidates heterogeneous structure(nm) of the inward-growing scale. • Spinel-miscibility gap is suggested to be related to performance after breakaway. [ABSTRACT FROM AUTHOR]

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

[Display omitted] • Plastic waste fuelled SOFCs gain highly improved performance by Fe 2 O 3 modified anode. • Pseudofuel nature of iron oxide in SOFCs is systematically examined. • Structural optimization of Fe 2 O 3 greatly enhances the discharge capacity of FeO. • Discharge capacity of FeO reaches 91% of theoretical value via FeO-Ag-GDC synergism. Waste plastics-to-power conversion via fuel cells is very attractive for its potential to be efficient and eco-friendly. Here we report a solid oxide fuel cell (SOFC) operating directly on waste polyethylene terephthalate (PET) with significantly improved performance due to the modification of anode with iron oxide (Fe 2 O 3) that functions as pseudofuel in its reduced form (FeO). The pseudofuel performance, namely the discharge capacity of FeO, was improved significantly by optimizing the structure of Fe 2 O 3 , and owing to the synergistic interaction of FeO with the anodic materials, i.e. silver and gadolinia doped ceria. A mechanism is proposed to reveal the synergistic effect of these materials in the discharge process. The maximum discharge capacity of 340 mAh/g for FeO was obtained, approaching 91 % of the theoretical value. Based on the optimized pseudofuel, the electrochemical performance of SOFCs directly fueled by waste PET was markedly enhanced: The peak power density of the cell increased from 115 to 320 mW cm−2, and the electric energy output of the PET fuel did from 0.0018 to 0.26 Wh/g (140-fold more). This work shows that SOFCs with Fe 2 O 3 modified Ag-based anode offer a promising platform for direct conversion of plastic waste to power in an efficient and green manner. [ABSTRACT FROM AUTHOR]

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

Chitosan (CS) polysaccharide is expected to exhibit greater ionic conductivity, which can be attributed to its increased amino group content when it is blended with different semiconducting materials. Herein, the work used this conducting ability of chitosan and prepared a heterogeneous MoS 2 -induced magnetic chitosan (MF@CS) composite via the co-precipitation method, which was used to scrutinize the catalytic performance with Methylene Blue (MB) and Malachite Green (MG) dyes by visible light irradiation. The saturation magnetization value of the MF@CS composite is found to be 7.8 emu/g, which is less when compared to that of pristine Fe 3 O 4 (55.7 emu/g) particles. The bandgap of the MF@CS composite is ∼ 2.17 eV, which exceeds the bandgap (E g) of bare MoS 2 of 1.80 eV. The maximum color removal of 96.3 % and 93.4 % for MB and MG dyestuffs is recognized in the exposure of the visible spectrum, respectively. At a starting dye dosage of 30 mg/L, 0.1 g/L of MF@CS, a pH level of 8−11, and 70 min of contact with direct light. The photocatalyst provides extremely good durability for a maximum of five phases. Hence, the MF@CS matrix is a viable and appropriate substance for the efficient treatment of effluents containing dye molecules. [Display omitted] [ABSTRACT FROM AUTHOR]

The presence of arsenic in groundwater, and through this in drinking water, has been shown to present a serious risk to public health in many regions of the world. In this study, two iron-rich carbonous adsorbents were compared for the removal of arsenate (As(V)) from groundwater. Biochars (FeO-biochar and FeO-pyrochar) derived from biomass waste were functionalised in two different ways with iron chloride for comparation. Batch and dynamic parameters were optimised to achieve >99% As(V) removal efficiency. Experimental data were best described by the pseudo-second order kinetic model, while multi-stage diffusion appeared to limit mass transfer of As(V). Among the isotherm models evaluated, the Freundlich model best described the experimental results with high correlation coefficients (R 2 ≥ 0.94) for both adsorbents. Monolayer adsorption capacities were found to be 4.34 mg/g and 8.66 mg/g for FeO-biochar and FeO-pyrochar, respectively. Batch studies followed by instrumental characterisation of the materials indicated the removal mechanisms involved to be electrostatic interactions (outer-sphere), OH− ligand exchange (inner-sphere complexation) and hydrogen bonding with functional groups. Higher pH pzc (9.1), S BET (167.2 m2/g), and iron/elemental content for the FeO-pyrochar (compared with the FeO-biochar) suggested that both surface chemistry and porosity/surface area were important in adsorption. Dynamic studies showed FeO-pyrochar can be used to remove As(V) from groundwater even at low 'environmental' concentrations relevant to legislative limits (<10 μg/L), whereby 7 g of FeO-pyrochar was able to treat 5.4 L groundwater. [Display omitted] • Surface chemistry and structure were crucial for determining As(V) adsorption. • As(V) adsorption was governed by Fe content, pH pzc and porosity. • Adsorption of As(V) on biochar occurred through complexation and hydrogen bonding. • Successful desorption even with highly diluted NaOH. • Efficient treatment of As(V) contaminated groundwater in dynamic column. [ABSTRACT FROM AUTHOR]

Hydrogen purification by removing CO traces was studied via the preferential CO oxidation (PROX) reaction using highly dispersed Pt catalysts supported on dual oxide FeO x /TiO 2. These catalysts were prepared by the strong electrostatic adsorption (SEA) method by varying the pH of synthesis and the calcination temperature. By measuring the point of zero charge (PZC) of the support components, it was possible to determine the pH in which Pt can be selectively deposited onto one of the support components, obtaining Pt dispersion values above 90%. The selective SEA of a Pt precursor onto the co-support (FeO x) was achieved at a synthesis pH between the PZCs of the support components (i.e., TiO 2 PZC = 5.2 and Fe 2 O 3 PZC = 6.9) by using a Pt anionic complex. The catalytic activity for the PROX reaction, expressed in terms of the CO conversion, O 2 selectivity to CO 2 , apparent activation energy, and turnover frequency, confirmed that the SEA prepared catalysts were active and selective for the PROX reaction. XPS and TPR results of the Pt/FeO x /TiO 2 catalysts showed the formation of Pt-FeO x interfaces, called as (Pt-FeO x) i interfacial sites, which enhanced the stability and catalytic activity for the PROX reaction. The concentration of these sites can be controlled by the synthesis conditions used, mainly pH and to a lower extent the calcination temperature. [Display omitted] • Pt/FeO x /TiO 2 catalysts were prepared by SEA at a pH that ensures a Pt selective deposition onto Fe-based support. • 1 nm Pt crystallites were selectively deposited over FeO x at a pH between the PZCs of the support components. • The formation of (Pt-FeO x) i interfacial sites were detected by XPS, TPR, TEM and operando DRIFTS analyses. • The concentration of (Pt-FeO x) i interfacial sites is affected by the calcination temperature and the synthesis pH. • The concentration of (Pt-FeO x) i interfacial sites was correlated with the activity of Pt–Fe catalysts in the PROX reaction. [ABSTRACT FROM AUTHOR]

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

[Display omitted] • In situ iron oxide nanoparticles were synthesized into heavy crude oil. • Magnetite and akaganeite nanoparticles in situ presented sizes of 20–43 nm. • Reaction conditions were at 200 nm3/m3 of H 2 /heavy crude oil ratio, 380 °C and 1 h. • Residue conversion was approximately 20 %. • Spent catalyst showed the iron sulfide phase, although no presulfiding was realized. We proposed a direct in situ synthesis method for iron oxide nanoparticles (NPs) along with catalytic erformance upgrading of heavy crude oil (HCO). Our method compares the upgrading of a HCO where other iron oxide nanoparticles were synthesized by a traditional thermal decomposition method of organometallic compounds in the presence of stabilizing agents and solvents of high boiling points. Furthermore, the in situ nanoparticles were extensively characterized by XRD, Mössbauer spectroscopy and TEM microscopy which confirmed the presence of magnetite and akaganeite phases, with an average diameter of 20−43 nm. Nanoparticles by thermal decomposition method were investigated by XRD, UHR-FE-SEM and HRTEM and showed the formation of magnetite nanoparticles with an average diameter of 6.7 ± 1.4 nm. Subsequently, the nanoparticles were evaluated in a batch reactor using HCO from the Golden Lane of Mexico at 44.1 bar (initial H 2 pressure) and 380 °C, for 1 h at 500 rpm. It was observed that, even under hydrogen limited conditions, there are better physicochemical properties in terms of viscosity, API gravity and heavy fractions decrease, for example, the residue conversion was about 20 % and the kinetic model was adjusted to a five lump model. The formation of the iron sulfide phase (FeS) was detected during the analysis of the spent catalyst. [ABSTRACT FROM AUTHOR]

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

A porous hematite/alumina nanocomposite is produced by sol-gel combustion synthesis. The XRPD, Raman and FTIR methods show the presence of α-Fe 2 O 3 phase while SEM, TEM, EDS and BET techniques further reveal the formation of porous ellipsoid-like nanostructure of hematite nanoparticles coated by amorphous alumina. Hematite nanoparticles have a size of ~40 nm whereas the porous hematite/alumina nanocomposite particles are ~100 nm in size with characteristic pores of ~7 nm. The M(H) at 300 K exhibits coercivity H C = 293 Oe and magnetization M S = 2.71 emu/g and at 5 K H C = 1150 Oe and M S = 9.25 emu/g. The M(T) under H = 100 Oe shows a bifurcation between ZFC/FC magnetization curves at all measurement temperatures T irr >350 K (irreversibility temperature) and blocking temperature at TB ~ 305 K. Unexpectedly, the M(T) measurements under H = 10 kOe reveal the suppressed Morin transition at T M = 225 K. The analysis of the results and data from the literature reveal that the porous surface structure of hematite induces the atypical magnetic properties. A magnetic resonance imaging (MRI) properties show the transverse relaxivity rate (r2) of 0.44 mM−1s−1 at 7 T and 1.06 mM−1s−1 at 15.2 T. The investigated nanocomposite particles could be useful in biomedical applications due to their low cytotoxicity and porous nanostructure. [ABSTRACT FROM AUTHOR]

Sonodynamic therapy (SDT) is a minimally invasive therapeutic approach, that uses ultrasound activating sonosensitizers to generate reactive oxygen species (ROS) for inducing the tumor cell death. However, the SDT is always limited by the dissatisfactory performance of sonosensitizers and hypoxic tumor microenvironment (TME). Nano iron oxide is a narrow bandgap semiconductor material with good biocompatibility. The doping of manganese into iron oxide (Mn-doped iron oxide nano-crystals named Mn-Fe 2 O 3 NCs) not only reduced the band gap of iron oxide and altered the valence band position of iron oxide, but also introduced more oxygen vacancies and inhibited the complexation of electrons (e-) and holes (h+), significantly enhancing the ability to generate ROS. The Mn-Fe 2 O 3 NCs improved the hypoxic TME by self-generating oxygen and consuming endogenous glutathione (GSH), which amplified oxidative stress and further enhanced the SDT. The therapeutic results showed that the prepared Mn-Fe 2 O 3 NCs could efficiently inhibit the triple-negative breast cancer (TNBC) cells by SDT (80.49 % inhibition ratio in vivo). Overall, we propose a simple method to design inorganic sonosensitizers for enhancing efficient sonodynamic therapy. • The doping of manganese reduced the band gap of iron oxide and altered the valence band position. • The doping introduced more oxygen vacancies and inhibited the complexation of electrons and holes. • The Mn-Fe 2 O 3 NCs improved hypoxia by self-generating oxygen and consuming endogenous glutathione. • The Mn-Fe 2 O 3 NCs showed outstanding sonodynamic therapy effect to inhibit triple-negative breast cancer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocomposites based on graphene nanoribbons and iron oxide nanoparticles were synthesized by varying the particle size. • Properties such as specific surface area, magnetic response and specific capacitance were investigated as a function of the particle size. • All the properties studied were strongly affected by the particle size. • Nanocomposites with a high specific surface area can be obtained by tuning the particle size. • The specific capacitance of the nanocomposites is increased with the specific surface area. The particle size effect on nanocomposites made of reduced graphene nanoribbons (GNRs) and iron oxide nanoparticles (IONPs) is studied. Three nanocomposites with different particle size were prepared by chemical reduction of IONPs formed by the co-precipitation method on graphene oxide nanoribbons. Several experimental techniques such as transmission electron microscopy, selected area electron diffraction and X-ray diffraction determined the particle size distribution and crystalline phases present in the samples. The specific surface area (SSA) of the nanocomposites was measured and discussed with the mean size of the IONPs. Depending on the mean size and surface distribution of the IONPs, samples with high SSA can be achieved. Magnetic measurements indicated that the particle size affects the magnetic properties of the nanocomposites. These results were discussed considering the effect of particle size, defects, amount of particles and interaction between the IONPs and GNRs surface. The potential application of the samples as supercapacitors was evaluated by calculating their specific capacitance from cyclic voltammetry measurements. The results showed that the specific capacitance increases with the SSA. This work confirms that the size of the IONPs significantly affects the properties of the nanocomposites, specifically the SSA, which is of great interest for various applications. [ABSTRACT FROM AUTHOR]

• Akaganeite showed high long-term reduction rate and extent mediated by DIRB. • Surface reactivity properties of iron oxides decide bio-transformation to vivianite. • P migrate and immobilize on iron oxides predetermine vivianite recovery. • Akaganeite was screened as superior iron source for P recovery in sewage. The reducibility of iron oxides, depending on their properties, influences the kinetics of dissimilatory iron reduction (DIR) during vivianite recovery in sewage. This study elucidated the correlation between properties of iron oxides and kinetics of DIR during the long-term transformation into vivianite, mediated by Geobacter sulfurreducens PCA and sewage. The positive correlation between surface reactivity of iron oxides and reduction rate constant (k) influenced the terminal vivianite recovery efficiency. Akaganeite with the highest adhesion work and surface energy required the lowest reduction energy (E a), obtained the highest k of 1.36 × 10–2 day-1 and vivianite recovery efficiency of 43 %. The vivianite yield with akaganeite as iron source was 76–164 % higher than goethite, hematite, feroxyhyte, and ferrihydrite in sewage. The distribution of P with akaganeite during DIR in sewage further suggested a more efficient pathway of direct vivianite formation via bio-reduced Fe(II) rather than indirect reduction of ferric phosphate precipitates. Thus, akaganeite was screened out as superior iron source among various iron oxides for vivianite recovery, which provided insights into the fate of iron sources and the cycle of P in sewage. [Display omitted] [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) and aggregate stability are critical indicators for assessing C sequestration potential in agricultural systems. Recent studies suggest that rice-crayfish coculture (RCC) enhanced SOC stocks in the topsoil layer. However, limited knowledge exists regarding the response and mechanisms of SOC and soil aggregation at deeper soil scales in long-term RCC models. Here, we investigated the effects of varying durations (5, 10, and 15 years) of RCC and rice monoculture (RM) in Qianjiang City, China on the vertical distribution of SOC, SOC functional groups, aggregates, organic matter fractions, and Fe oxides down to the depth of 1-meter. The results revealed that RCC significantly increased SOC content and storage throughout the soil profile by 54 % and 43 %, respectively, compared to RM. Moreover, RCC enhanced alkyl-C/alkoxy-C, hydrophobicity, and aromaticity of SOC functional groups. Additionally, RCC promoted the formation of macroaggregates and particle organic matter, indicating improved soil structure. Fe oxides were identified as strong drivers for SOC contents and soil aggregation, explaining 30 % and 32 % of the variation, respectively. Specifically, SOC contents were best explained by OC/Fe molar ratio (13 %), while organically complexed Fe oxides provided the optimal explanation for soil aggregation (11 %). RCC improved aggregate stability by enriching organic carbon and activating Fe oxides, thus significantly enhancing C preservation potential. This study underscores the importance of RCC in enhancing soil quality and carbon sequestration capacity, offering insights into innovative practices for sustainable agriculture. [Display omitted] • RCC elevated SOC levels at 1-m depth with upward trend as RCC duration prolonged. • RCC contributed to the enhancement of SOC structural complexity and chemical stability. • RCC improved soil aggregation via cPOM increase and free-SC reduction. • Enriching organic carbon and activating Fe oxides facilitated C-Fe associations. [ABSTRACT FROM AUTHOR]

[Display omitted] • VFAs can be obtained from an aqueous solution derived by the fermentation of food waste; • Their recovery is pivotal for economic and environmental reasons; • Iron oxide NPs with functionalization or not showed low reproducible results; • Liquid-liquid extraction can be used showing higher efficiency; • the use of oleic acid presented extraction capacity up to 97% and good reproducibility. The extraction of volatile fatty acids (VFAs) from an aqueous solution derived by fermentation of food waste is a key challenge in the context of the circular economy, thanks to their high economic and environmental impact due to their wide-ranging use in various industrial fields. In this work, we compared two different extraction methods: one novel and one classical. Firstly, iron oxide nanoparticles of around 10 nm were prepared and used as they are or functionalised using (3-Aminopropyl)triethoxysilane) (APTES) molecules, adipic acid and oleic acid. This was compared with a traditional industrial method (liquid–liquid extraction) that can guarantee high extraction of VFAs with high reproducibility. Indeed the use of dichloromethane, hexane, methyl tert -butyl ether and oleic acid presented extraction values of up to 30 % while iron oxide NPs showed results with low reproducibility. The comparison demonstrated the use of oleic acid as a promising solvent for liquid–liquid extraction of VFAs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe 2 O 3 : Ag(1–9 mol %) nanoparticles synthesized via co-precipitation method. • Powder X-ray diffraction shows a hexagonal crystal structure. • Photoluminescence analysis carried out for display applications. • Cytotoxic properties are discussed. • Oxygen evolution kinetics are studied for energy storage applications. Fe 2 O 3 : Ag(1–9 mol %) nanoparticles (NPs) have been synthesized through the co-precipitation method. Crystallite size, phase, crystallinity, and structural parameters were analyzed by using powder X-ray diffraction. The Bragg reflections confirm that the synthesized NPs crystallize in hexagonal crystal structure with space group R - 3 c. Surface morphology consists of agglomerated irregular size and roughly spherical-shaped NPs. Energy Dispersive Analysis of X-ray confirms the presence of Fe, O, and Ag elements and also the purity of the sample. Crystallite size decreased with the increase in dopant concentration. Direct band gap energy is found to increase with an increase in dopant concentration. Photoluminescence and anticancer properties were studied in detail. The CIE coordinates confirm red emission in the visible region. CIE and CCT co-ordinate values indicate cool light emission, hence, the synthesized nanophosphor material meets the demand of display technology. Further anticancer properties were investigated on HeLa cells and compared with the standard drug cisplatin for biomedical applications. Further, Oxygen evolution reaction kinetics was investigated for Fe 2 O 3 :Ag (1 mol %) nanoparticles. demonstrates enhanced oxygen evolution reaction performance with a low overpotential of 348 mV, as shown by linear sweep voltammetry. It also exhibits a favorable Tafel slope of 83 mV/dec, indicating efficient electron transfer kinetics, making it a promising candidate for OER applications. [ABSTRACT FROM AUTHOR]

We investigated the H 2 sensing performance of pure α -Fe 2 O 3 and Pt/ α -Fe 2 O 3 samples, where platinum was mechanochemically dispersed on reducible α -Fe 2 O 3 supports by ball miling, at concentrations of 1, 3, 5 and 10 mol%. The hematite nature of the supports was confirmed by Mössbauer spectroscopy. Raman spectroscopy reveals signature lines of hematite as well as "forbidden" longitudinal optical modes indicating stress-induced asymmetry. Scanning and transmission electron micrographs show nanometer-sized Pt dots dispersed on loosely aggregated α -Fe 2 O 3 crystallites with a diameter of ⪆ 50 nm. Pt/ α -Fe 2 O 3 powder was suspended in ethanol and drop-cast onto glass substrates with interdigitated electrodes. The samples were exposed to H 2 concentrations from 0 – 500 ppm at different temperatures from 293 K to 553 K. The electrical resistance of the samples with Pt decreased with increasing H 2 concentration even at room temperature, indicating sensitivity to H 2. The sensitivity and response time improved significantly at higher temperatures. The response and response time at 100 ppm H 2 ranged from ∼ -10% and ⪆ 75 s at 298 K to ∼ -50% and ∼ 5 s at 553 K. No dependence of the sensitivity on the Pt loading was observed, but a Pt loading of at least 1 mol% is essential for the sensors to function. The behavior of the sensors suggests a reversible sensing mechanism based on the Pt-mediated interaction of H 2 with adsorbed oxygen. These results indicate a possible use of Pt/ α -Fe 2 O 3 as a sensor for H 2 with a linear response at concentrations of 0–100 ppm and encourage further research. [Display omitted] • We have studied the H 2 sensing performance of pure α − Fe 2 O 3 and Pt/ α − Fe 2 O 3 samples. • The samples were exposed to H 2 concentrations (0 – 500 ppm) at different temperatures. • Samples with Pt were sensitive to H 2 and their sensor response improved at higher temperatures. • Results suggest a potential use of Pt/ α − Fe 2 O 3 as a sensor for H 2 with a linear response at concentrations of 0–100 ppm and encourage further research. [ABSTRACT FROM AUTHOR]

Alpha titanium bis(hydrogenphosphate) monohydrate, α-Ti(HPO 4) 2 ·H 2 O, (α-TiP) is a precursor material utilized to obtain a broad range of important compounds having a great deal of applications ranging from ion-exchange chromatography, chemical catalysis to energy storage materials. The novel synthetic procedure developed in this study shows a higher conversion of titanium in ilmenite to α-TiP with a good purity. For the synthesis of TiPs, the direct use of natural ilmenite ore with commonly available chemicals such as KOH, H 3 PO 4 , HCl, and H 2 C 2 O 4 highlights the significance of the present investigation. A mixture of ilmenite and KOH with a molar ratio of 1:4 was roasted at 800 ° C for 4 h to concentrate all the titanium to potassium titanate and iron to iron oxide. A reaction between potassium titanate and iron oxide with 85% (w /w) H 3 PO 4 acid results in a leachate rich in iron in the form of soluble iron phosphates and a white precipitate identified as α-TiP. Calcination of α-TiP at 800 ° C produces titanium pyrophosphate, TiP 2 O 7. Residual iron that co-precipitated with α-TiP was further removed by multiple washing steps with complexing acids; H 3 PO 4 or concentrated HCl. Washing with oxalic acid (H 2 C 2 O 4) produces a precipitate upon calcination identified as titanyl pyrophosphate, (TiO) 2 P 2 O 7. Flowcharts were developed and the chemical identities and the purity of the prepared α-Ti(HPO 4) 2 ·H 2 O and (TiO) 2 P 2 O 7 were tested with X-ray diffraction, X-ray fluorescence, thermogravimetric, and Raman spectroscopic techniques. • Preparation of potassium titanate and iron oxide mixture (BP) by roasting ilmenite with KOH. • BP reaction with H 3 PO 4 forms a white powder (WP), α-TiP, upon calcination produce pyro-TiP. • Residual iron removal from WP by washing with H 3 PO 4 , HCl, and H 2 C 2 O 4 acids. • Maximum yield of 93 wt% α-TiP was achieved from ilmenite with high purity. [ABSTRACT FROM AUTHOR]

This work presents a magnetic purification method of human erythrocyte Acetylcholinesterase (EC 3.1.1.7; AChE) based on affinity binding to procainamide (Proca) as ligand. Acetylcholinesterase is an acetylcholine-regulating enzyme found in different areas of the body and associated with various neurological disorders, such as Parkinson, Alzheymer and Amyotrophic Lateral Sclerosis. AChE from human erythrocyte purification has been attempted in recent years with low degree of purity. Here, magnetic nanoparticles (MNP) were synthesized and coated with polyaniline (PANI) and procainamide (PROCA) was covalently linked to the PANI. The extracted human erythrocyte AChE formed a complex with the MNP@PANI-PROCA and an external magnet separated it from the undesired proteins. Finally, the enzyme was collected by increasing the ionic strength. Experimental Box-Behnken design was developed to optimize this process of human erythrocyte AChE purification protocol. The enzyme was purified in all fifteen experiments. However, the best AChE purification result was achieved, about 2000 times purified, when 100 mg of MNP@PANI-PROCA was incubated for one hour with 4 ml hemolysate extract. The SDS-PAGE of this preparation presented a molecular weight of approximately 70 kDa, corroborating with few previous studies of AChE from erythrocyte purification. • Acetylcholinesterase dysregulation is associated with several neurological diseases and could be useful to a possible biomarker. • Iron Magnetic Particles revested with polyaniline (PANI) were synthesized using procainamide as a specific ligand. • Hemolysate with Erythrocyte AChE was exposed to MNP@PANI-Proca, washed to remove unbound proteins by magnetic field and AChE was leached under high ionic strength. • Purification was optimized to obtain purified enzyme up to 2,000 times higher and a yield up to 400%. [ABSTRACT FROM AUTHOR]