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In this paper, the design, synthesis and catalytic application of a magnetic covalent organic framework modified with sulfonic acid (Fe3O4@COF-SO3H) in the synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives, were studied. The structure of the prepared catalyst was confirmed by various techniques including Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy, thermo-gravimetric analysis, field emission scanning electron microscopy, vibrating-sample magnetometer and Brunauer–Emmett–Teller porosimetry. The structure of the prepared derivatives was also confirmed using FT-IR and nuclear magnetic resonance (1HNMR and 13CNMR) spectroscopy. Facile synthesis, solvent-free conditions, high yield, short reaction time, eco-friendly procedure, and straightforward work-up are among the advantages of this research. [ABSTRACT FROM AUTHOR]

Bone tissue engineering addresses the limitations of autologous resources and the risk of allograft disease transmission in bone diseases. In this regard, engineered three‐dimensional (3D) models emerge as biomimetic alternatives to natural tissues, replicating intracellular communication. Moreover, the unique properties of super‐paramagnetic iron oxide nanoparticles (SPIONs) were shown to promote bone regeneration via enhanced osteogenesis and angiogenesis in bone models. This study aimed to investigate the effects of SPION on both osteogenesis and angiogenesis and characterized a co‐culture of Human umbilical vein endothelial cells (HUVEC) and MG‐63 cells as a model of bone microtissue. HUVECs: MG‐63s with a ratio of 4:1 demonstrated the best results among other cell ratios, and 50 μg/mL of SPION was the optimum concentration for maximum survival, cell migration and mineralization. In addition, the data from gene expression illustrated that the expression of osteogenesis‐related genes, including osteopontin, osteocalcin, alkaline phosphatase, and collagen‐I, as well as the expression of the angiogenesis‐related marker, CD‐31, and the tube formation, is significantly elevated when the 50 μg/mL concentration of SPION is applied to the microtissue samples. SPION application in a designed 3D bone microtissue model involving a co‐culture of osteoblast and endothelial cells resulted in increased expression of specific markers related to angiogenesis and osteogenesis. This includes the design of a novel biomimetic model to boost blood compatibility and biocompatibility of primary materials while promoting osteogenic activity in microtissue bone models. Moreover, this can improve interaction with surrounding tissues and broaden the knowledge to promote superior‐performance implants, preventing device failure. [ABSTRACT FROM AUTHOR]

Iron or its oxides (FexOy) commonly exist in the ash of fossil fuel and biomass, and are used as oxygen carriers in chemical looping process, and Fe3O4 is a main occurrence. The NO reduction mechanisms by CO over Fe3O4 (111) surface was investigated via density functional theory (DFT) calculations. An optimized unit cell of Fe3O4 was constructed. The interaction between molecules and cell surface was described by the calculated adsorption properties and electronic structures. Results showed that the most stable adsorption of NO/CO belongs to chemisorption and NO has higher adsorption energy than CO. NO can be absorbed onto Fe3O4 surface to form (NO)2 dimer structure, which easily decomposes via a small energy barrier. (NO)2 dimer mechanism is a possible pathway for the reduction of NO by CO over Fe3O4, following three steps: 2NO → (NO)2*, (NO)2* → N2O + O*, O* + CO* → CO2. After the decomposition, the intermediate species N2O molecule and the remaining O atom adsorbed strongly on the Fe3O4 surface can be removed by CO. CO also promotes the gaseous decomposition of N2O. DFT results also showed O2 will prevent NO reduction reaction. The calculated reaction rate constants further verify the existence of (NO)2 dimer mechanism and the rate-limiting step is the removal of the surface O atom. [ABSTRACT FROM AUTHOR]

Efficient and economical catalysts are pivotal for enhancing burning rate and reducing gas pollutants (e.g. NO and SO2) during coal combustion. This work evaluated the feasibility of using economical Fe3O4-based catalysts to enhance combustion rate and reduce NOx in-situ. Fe3O4 alone is found to be effective in both catalytic combustion and NO reduction, and the optimized addition is 6% based on the fuel mass. The enhancement of burning rate is mainly due to the enhanced oxygen transport with Fe3O4. Meanwhile, Fe3O4 promotes the reduction of NO with CO and coke, while CO2 and O2 in the atmosphere have adverse effect on its catalysis activity during combustion. Both CaO and CeO2 can be used to improve the efficacy of Fe3O4, and the optimal addtion was 10% CaO or 2% CeO2 together with 2% Fe3O4 for catalytic coal combustion. On the other hand, for the catalysis on NO reduction, the combination fo 2% Fe3O4-4% CaO or 2% Fe3O4-4% CeO2 could minimize the amount of NO emitted during combustion. The enhanced oxygen transfer and electron transfer are responsible for the accelerated combustion and NO reduction for the composite catalysts. [ABSTRACT FROM AUTHOR]

The nanocomposites of ferroferric oxide (Fe3O4) with polyhydroxyurethane (PHU) were fabricated via a physical mixing approach. This process involved grafting poly(N‐vinyl pyrrolidone) (PVPy) chains onto the surfaces of Fe3O4 nanoparticles via surface‐initiated living radical polymerization. The PVPy‐grafted Fe3O4 nanoparticles were directly incorporated into the precursors of PHUs [i.e., bis(cyclic carbonate) and a trifunctional amine] and the mixtures were cured at high temperatures to form organic–inorganic composites. This method ensured that Fe3O4 nanoparticles were finely dispersed within the PHU matrix through the strong intermolecular hydrogen bonding between PVPy and PHU. Compared to plain PHU network, the nanocomposites had enhanced thermomechanical properties, including higher glass transition temperatures (Tg's) and improved tensile mechanical properties. The inclusion of Fe3O4 nanoparticles also enhanced the shape memory properties of the PHU networks, improving shape recovery rates, fixity of transient shapes, and recovery of the original shapes. In addition, the nanocomposites demonstrated paramagnetic and photothermal properties and the photothermal behavior enabled a non‐contact control of shape recovery. Highlights: Poly(N‐vinyl pyrrolidone)‐grafted Fe3O4 nanoparticles were synthesized.Nanocomposites of PHU with Fe3O4 were prepared via a physical blending approach.Incorporation of Fe3O4 resulted in improved thermomechanical properties.The nanocomposites had the photothermal properties. [ABSTRACT FROM AUTHOR]

Water coloring has the properties of resistance to mutagenic, toxic, aggressive, carcinogenic, destructive, strong light and unstable oxidation and air pollution and has serious effects on environmental systems and human health. Because of its severe toxicity, methylene blue (MB) can cause cancer, mutagenesis, and teratogenic consequences in people as well as enter the food chain. The main objective of this investigation is to study the modeling and the optimization parameters of MB adsorption using a low‐cost adsorbent Fe3O4. The parameters evaluated for adsorption are the adsorbent dosage, pH, contact time, and temperature using the response surface methodology. The principal variables affecting MB removal were pH (3–11), catalyst dosage (0.01–0.3 g), contact duration (10–180 min), and temperature (25–55 °C). To select an experimental domain, a preliminary study was performed first. The results showed that at pH 10, 1.4 g L−1 Fe3O4‐nanoparticles (NPs) had the highest removal efficiency of cationic dye MB (20 ppm) from aqueous solutions by batch adsorption technique. The pseudo‐second‐order (PSO) kinetic models and the Langmuir isotherm provided the best fit for the adoption of MB. The adsorption process was exothermic and spontaneous, according to thermodynamics studies. To determine the effect of the investigated variables and their interaction on the adsorption process, a Box–Behnken design was used. A second‐order polynomial equation was used to model the experimental results. The experimental findings were consistent with the suggested model as demonstrated by the high value of the determination coefficient. The performance of the model equation verified the experimental observation with just a slight divergence, and the values acquired from the experiment and model predictions were found to be in suitable agreement. According to the numerical optimization, 98.61 % is the optimal elimination efficiency for MB adsorption. These results suggest that an adsorption process utilizing Fe3O4 NPs is efficient in environmental remediation. [ABSTRACT FROM AUTHOR]

Wastewater containing heavy metal ions poses great harm to human health and the environment. The adsorption materials used in traditional adsorption methods, such as starch and cellulose, are prone to hydrolysis, causing secondary pollution to water bodies. Nylon@Fe3O4@PAA adsorption material was obtained by using nylon as a substrate, activating nylon with sodium carbonate/hydrochloric acid, depositing a Fe3O4 magnetic layer by coprecipitation, and grafting polyacrylic acid. The adsorption material was used to explore the effects of different conditions (adsorption material dosage, Cu2+ concentration, pH value, and adsorption time) on the adsorption efficiency, adsorption capacity, and total adsorption amount of copper ions through changing the adsorption conditions. The research results showed that the adsorption material dosage was 31.25 mg (suspension solution with a concentration of 62.5 mg/mL was added with 300 μL), the concentration of Cu2+ solution was 20.48 mg/L, the adsorption time was 60 min, and the pH value was 9. The optimal adsorption efficiency was 82.29%, the optimal adsorption capacity was 154.87 mg/g, and the optimal total adsorption amount was 343.91 mg. After fitting thermodynamic and kinetic equations, the adsorption process of nylon@Fe3O4@PAA for Cu2+ ions dominated by chemical adsorption, with good adsorption rate and adsorption performance. [ABSTRACT FROM AUTHOR]

Methylene blue pollutants can be treated by photocatalytic methods using metal oxide-based semiconductor materials and metal organic framework (MOF). These two materials are often coupled into a composite to improve their physicochemical properties and catalytic activity. This research focuses on the synthesis of composites based on Cr-PTC MOF, ZnO, and Fe3O4 by the sonochemical method. The obtained composites were characterized and tested for catalytic activity in methylene blue pollutant degradation in an aqueous system under acidic conditions (pH = 5). Our investigation shows that the Cr-PTC@Fe3O4 composite possesses the lowest band gap energy of 1.86 eV and achieves the highest photocatalytic activity in methylene blue degradation at solution pH = 5, with a percent degradation of 84.36%. The sonochemical incorporation of Fe3O4 and Cr-PTC MOF is able to fabricate materials in a short time with better photocatalytic activity in degrading methylene blue than the single materials. [ABSTRACT FROM AUTHOR]

In order to improve dispersibility, polymerization characteristics, chemical stability, and magnetic flocculation performance, magnetic Fe3O4 is often assembled with multifarious polymers to realize a functionalization process. Herein, a typical three-dimensional configuration of hyperbranched amino acid polymer (HAAP) was employed to assemble it with Fe3O4, in which we obtained three-dimensional hyperbranched magnetic amino acid composites (Fe3O4@HAAP). The characterization of the Fe3O4@HAAP composites was analyzed, for instance, their size, morphology, structure, configuration, chemical composition, charged characteristics, and magnetic properties. The magnetic flocculation of kaolin suspensions was conducted under different Fe3O4@HAAP dosages, pHs, and kaolin concentrations. The embedded assembly of HAAP with Fe3O4 was constructed by the N–O bond according to an X-ray photoelectron energy spectrum (XPS) analysis. The characteristic peaks of –OH (3420 cm−1), C=O (1728 cm−1), Fe–O (563 cm−1), and N–H (1622 cm−1) were observed in the Fourier transform infrared spectrometer (FTIR) spectra of Fe3O4@HAAP successfully. In a field emission scanning electron microscope (FE-SEM) observation, Fe3O4@HAAP exhibited a lotus-leaf-like morphological structure. A vibrating sample magnetometer (VSM) showed that Fe3O4@HAAP had a relatively low magnetization (Ms) and magnetic induction (Mr); nevertheless, the ferromagnetic Fe3O4@HAAP could also quickly respond to an external magnetic field. The isoelectric point of Fe3O4@HAAP was at 8.5. Fe3O4@HAAP could not only achieve a 98.5% removal efficiency of kaolin suspensions, but could also overcome the obstacles induced by high-concentration suspensions (4500 NTU), high pHs, and low fields. The results showed that the magnetic flocculation of kaolin with Fe3O4@HAAP was a rapid process with a 91.96% removal efficiency at 0.25 h. In an interaction energy analysis, both the UDLVO and UEDLVO showed electrostatic repulsion between the kaolin particles in the condition of a flocculation distance of <30 nm, and this changed to electrostatic attraction when the separation distance was >30 nm. As Fe3O4@ HAAP was employed, kaolin particles could cross the energy barrier more easily; thus, the fine flocs and particles were destabilized and aggregated further. Rapid magnetic separation was realized under the action of an external magnetic field. [ABSTRACT FROM AUTHOR]

The magnetite-silica (Fe3O4-SiO2) composites with high magnetite contents for microwave heating elements were fabricated by the non-firing solidification method. Although the obtained solidified composite had a relative density of 47-57% and was not a dense body, it had sufficient mechanical strength due to the solidification of the silica phase. The magnetite in the composite functions as the microwave heating phase, and the SiO2 phase and pore phase function as the microwave permeable phase, resulting in a structure that allows uniform heating to reach the inside of the composite structure. It was clarified that the solidified composite could generate heat up to about 500°C without oxidizing during the microwave heating process. [ABSTRACT FROM AUTHOR]

A novel and environmentally friendly magnetic iron zeolite (MIZ) core–shell were successfully fabricated using municipal solid waste incineration bottom ash-derived zeolite (MWZ) coated with Fe3O4 and innovatively investigated as a heterogeneous persulfate (PS) catalyst. The morphology and structure composition of as-prepared catalysts were characterised, and it was proved that the core–shell structure of MIZ was successfully synthesised by coating Fe3O4 uniformly on the MWZ surface. The tetracycline hydrochloride (TCH) degradation experiment indicate that the optimum equimolar amount of iron precursors was 3 mmol (MIZ-3). Compared with other systems, MIZ-3 possessed a superior catalytic performance, and the degradation efficiency of TCH (50 mg·L−1) in the MIZ-3/PS system reached 87.3%. The effects of reaction parameters on the catalytic activity of MIZ-3, including pH, initial concentration of TCH, temperature, the dosage of catalyst, and Na2S2O8, were assessed. The catalyst had high stability according to three recycling experiments and the leaching test of iron ions. Furthermore, the working mechanism of the MIZ-3/PS system to TCH was discussed. The electron spin resonance (ESR) results demonstrated that the reactive radicals generated in the MIZ-3/PS system were sulphate radical (${\rm S}{\rm O}_4^- \bullet$ S O 4 − ∙) and hydroxyl radical (•OH). This work provided a novel strategy for TCH degradation under PS with a broad perspective on the fabrication of non-toxic and low-cost catalysts in practical wastewater treatment. [ABSTRACT FROM AUTHOR]

Today, high-energy applications are devoted to boosting the storage performance of asymmetric supercapacitors. Importantly, boosting the storage performance of the negative electrodes is a crucial topic. Fe3O4-based active materials display a promising theoretical storage performance as a negative electrode. Thus, to get a high storage performance of Fe3O4, it must be tailored to have a higher ionic and electronic conductivity and outstanding stability. Functionalized graphite felt (GF) is an excellent candidate for tailoring Fe3O4 with a facile ionic and electronic pathway. However, the steps of the functionalization of GF are complex and time-consuming as well as the energy loss during this step. Thus, the in-situ functionalization of the GF surface throughout the synthesis of Fe3O4 active materials is proposed herein. Fe3O4 is electrodeposited at the in-situ functionalized GF surface with the crystalline nanowires-like structure as revealed from the various analyses; SEM, TEM, Mapping EDX, XPS, XRD, wettability test, and Raman analysis. Advantageously, the synthetic approach introduces full homogeneous and uniform coverage of the large surface area of the GF. Thus, Fe3O4 nanowires with high ionic and electronic conductivity are characterized by a higher storage performance. Interestingly, Fe3O4/GF possesses a high specific capacity of 1418 mC cm−2 at a potential scan rate of 10 mV s−1 and this value retained to 54% at a potential scan rate of 50 mV s−1 at an extended potential window of 1.45 V. Remarkably, the diffusion-controlled reaction is the main contributor of the storage of Fe3O4/GF electrode as revealed by the mechanistic studies. [ABSTRACT FROM AUTHOR]

Nanoparticles have been widely applied to treat emulsion-containing wastewater in the form of chemical demulsifiers, such as SiO2, Fe3O4, and graphene oxide (GO). Owing to their asymmetric structures and selective adsorption, Janus nanoparticles show greater application potential in many fields. In the present work, the novel magnetic Janus graphene oxide (MJGO) nanoparticle was successfully prepared by grafting magnetic Fe3O4 to the surface of the JGO, and its demulsifying ability to treat a crude oil-in-water emulsion was evaluated. The MJGO structure and its magnetic intensity were verified by Fourier-transform infrared spectra (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), and magnetization saturation (MS) tests. Compared with GO and JGO, MJGO displayed the superior efficiency (>96%) to demulsify the crude oil-in-water emulsion, which can be attributed to the reduced electrostatic repulsion between MJGO and the emulsion droplets. Furthermore, the effects of pH and temperature on the demulsification performance of MJGO were also studied. Lastly, the recyclability of MJGO largely reduced the cost of demulsifiers in separating crude oil and water. The current research presents an efficient and recyclable demulsifier, which provides a new perspective for the structural design of nanomaterials and their application in the field of demulsification. [ABSTRACT FROM AUTHOR]

Tunable strong microwave absorption (MA) materials with minimum reflection loss (RLmin) in the low-frequency range (2–8 GHz) are crucial for civilian and military applications, yet remain insufficiently explored. Herein, we design and fabricate hierarchical-structured carbon nanotube (CNT)/Fe3O4(FeS2)/MoS2 composite materials using a facile solvothermal and hydrothermal synthetic method, achieving tunability in MA frequencies from the S-band (2–4 GHz) to the C-band (4–8 GHz) by manipulating the sulfur source. The optimal sample exhibits an RLmin of −70.06 dB at 3.74 GHz, a maximum effective absorption bandwidth (EABmax) of up to 5.6 GHz at 2–18 GHz, and an EABmax of 2.1 GHz at 2–8 GHz. Furthermore, the optimal sample shows excellent radar cross-section values and robust corrosion-resistive properties for practical radar stealth within corrosive environments. Our work provides a strategy to fabricate not-previously reported tunable strong microwave CNT-based absorbers with RLmin in low frequencies and give insights into their structures, physical properties, and potential applications. [ABSTRACT FROM AUTHOR]

The application of smart devices and artificial intelligence (AI) technologies has led to an increase in electromagnetic interference (EMI) issues. Compared with the traditional metal-based EMI shielding materials, lighter and more efficient polymer-based EMI shielding materials have a broader application prospect. In this work, we utilized electrospinning and calcination techniques to synthesize Fe3O4 nanofibers and employed a layer-by-layer assembly method to create a Ti3C2Tx MXene/Fe3O4/carbon fiber fabric/waterborne polyurethane (Ti3C2Tx MXene/Fe3O4/CFf/WPU) composite fabric. Our findings reveal that this composite fabric possesses superior EMI shielding capabilities. Specifically, the FMC12.5–5 composite material, which contains 12.5 wt % Fe3O4 and 5 wt % Ti3C2Tx, demonstrates remarkable electromagnetic interference (EMI) shielding effectiveness (SE) (up to 43.6 dB) at a mere 0.4 mm thickness with a low MXene content. Meanwhile, the fabric achieves a significant anisotropic thermal conductivity of up to 0.46 W/(m K), fulfilling the in-plane thermal conductivity requirement. Additionally, the sandwich-structured composite exhibits excellent mechanical performance (Young's modulus is up to 113.5 MPa and tensile strength reaches 15.7 MPa) and is flexible enough to endure repeated bending, folding, and shaping. It maintains a reliable electrothermal conversion capability, achieving temperatures of up to 106 °C at only 2.5 V. This study has expanded the exploration of enhanced electromagnetic interference (EMI) shielding and electrothermal conversion capabilities. [ABSTRACT FROM AUTHOR]

In this new era of globalization, magnetic adsorbents have gained vast attention from researchers in wastewater treatment applications. In this study, sulphonated magnetic multi-walled carbon nanotubes (S-MMWCNTs) were used to remove methylene blue (MB) from an aqueous solution. The S-MMWCNTs are characterized by various analytical methods to investigate their adsorbent features. Adsorption behaviours of the as-prepared composites affected by solution pH and contact time were systematically studied and discussed. The adsorption kinetic data fit the pseudo-second-order kinetic model well. Moreover, the MB removal efficiency of SMMWCNTs only drops slightly (~6.5%) after five consecutive adsorption cycles, showing their good stability and recyclability. [ABSTRACT FROM AUTHOR]

Free enzymes cause difficulties in many applications due to their insufficient stability, loss of activity in a short time, and most importantly, although they are costly, they are used only once in reactions, lose their effect and cannot be recovered from the environment. Magnetic nanoparticles coated with biocompatible polymeric material are potential candidates for promising enzyme carriers due to their multifunctional pore surfaces, easy removal from the environment provided by the magnetization, ability to main stability under various harsh conditions. This study prepared a biosensor candidate based on the inhibiting acetylcholinesterase enzyme by organophosphate pesticides from chitosan-coated magnetic nanoparticles doped with gold. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction diffractometry, and Fourier transform infrared spectroscopy analysis confirmed the structure of synthesized nanocomposites. Magnetic characteristics of the nanocomposites were assessed using VSM. Bio-nanocomposite (Fe3O4@Cht/Au/AChE) was used to determine environmental pollutants qualitatively. Remediation of organophosphate-containing wastewater is an essential issue for environmental sustainability. In this work, Dichlorvos and Chlorpyrifos were selected as organic pollutants to assess the enzymatic activity of immobilized Fe3O4@Cht/Au/AChE. Optimum conditions for AChE enzyme were immobilized nanostructures (Fe3O4@Cht/Au/AChE) were determined. The optimum pH for the immobilized enzyme was found to be 8, and the optimum temperature was found to be 60 °C. Retained immobilized enzyme activity is found to be around 50% for the 20th reuse. In the presence of 150 µL pesticide, retained immobilized enzyme activity is found to be around 25%. Method validation was performed for pesticides. When using immobilized AChE, the LOD (limit of detection)-LOQ (limit of quantitation) values for Dichlorovos and Chlorpyrifos was obtained in the range of 0.0087–0.029 nM and 0.0014–0.0046 nM, respectively. The relative standard deviation (RSD%) values, which are indicators of precision, were found to be below 2%. [ABSTRACT FROM AUTHOR]

In this research, pure polyaniline (PANi), pure magnetite (Fe3O4), and then PANi/ Fe3O4 nanocomposites were prepared and characterized. FT-IR spectra of the prepared samples indicate successful polymerization of PANi onto Fe3O4. PANi/Fe3O4 nanocomposites exhibit broad absorption bands at specific wavenumbers, indicating the presence of various functional groups. The observed blue shift in certain peaks suggests the interaction between nitrogen atoms and oxygen atoms on the magnetite surface through hydrogen bonding. The intensity and wavenumber of the Fe3O4 band decrease, indicating weakened Fe–O bonds. These findings demonstrate a strong interaction and combination between PANi and Fe3O4 in the nanocomposites. Fe3O4 nanoparticles exhibit a regular spherical shape with an average diameter of 16 nm. However, they also show non-uniform size distribution due to aggregation into larger secondary particles, likely driven by attractive forces. PANi/Fe3O4 core-shell nanocomposites demonstrate clear morphological changes, with Fe3O4 nanoparticles well spread and wrapped by the PANi shell. The electron diffraction technique confirms the crystalline structure of Fe3O4 nanoparticles, showing diffraction rings consistent with magnetite. The results confirm the potential of incorporating magnetic Fe3O4 nanoparticles to impart magnetic functionality in the resulting PANi-based nanocomposite materials. Magnetic saturation measurements displayed an enhancement in magnetization with increasing Fe3O4 nanoparticles. The change in magnetic behavior for doped samples provides a means of tuning the magnetization strength of the composites to meet the application requirement such as data storage and magnetic sensors. [ABSTRACT FROM AUTHOR]

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A novel smart catalyst was developed with amino‐modified thermo‐responsive poly(N‐isopropyl acrylamide) (PNIPAM) grafts on silica‐coated magnetic nanoparticles using the conventional free radical polymerization process. By this methodology, the polymer was successfully grafted mainly onto silica‐modified iron oxide nanoparticles (Fe3O4@Si). The PNIPAM‐grafted Fe3O4@Si was then subjected to ethylenediamine treatment to produce the amino‐functionalized support (Fe3O4@Si@PNIPAM‐NH2), which was subsequently modified with carboxyl functional groups by using EDTA (ethylenediaminetetraacetic acid) to create Fe3O4@Si@PNIPAM‐NH2‐EDTA. Au nanoparticles were then decorated on this support through its two amines and four carboxylates. Different methods were used to study this novel catalyst, including inductively coupled plasma, Fourier transport infrared spectroscopy, TGA, dynamic light scattering, SEM, energy‐dispersive X‐ray analysis, vibrating sample magnetometry, XRD and elemental CHN analysis. The reduction of several aryl‐nitro derivatives demonstrated a significant catalytic activity for the as‐synthesized gold catalyst (Fe3O4@Si@PNIPAM‐NH2‐EDTA‐Au). The Au catalyst can be successfully removed from the reaction components using a magnetic field and used again in eight successive reduction reactions without significant gold leaching and loss of catalytic activity. © 2024 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Electrification of adsorption processes is emerging as an adaptable solution for future gas separations. This study develops magnetic sorbent structures for use in induction vacuum swing adsorption (IVSA) process specifically designed for olefin/paraffin separation. Two sorbents, namely Fe3O4/ZIF‐7 (ethane‐selective) and Fe3O4/13X (ethylene‐selective) were developed and formulated into extrudates (Fe20/ZIF‐7‐P) and monoliths (Fe20/13X‐M), and tested under different regeneration scenarios, including simultaneous and subsequent induction‐evacuation, induction only, and evacuation only. The dynamic adsorption results demonstrated that regeneration under subsequent induction‐evacuation improves desorption rate and capability. Under this regeneration scenario, Fe20/ZIF‐7‐P achieved an ethane desorption rate of 0.24 mmol/g.min, representing a remarkable 37.5% enhancement over the induction‐only scenario. Similarly, Fe20/13X‐M exhibited an ethylene desorption rate of 0.35 mmol/g.min, indicative of a 34.2% enhancement. Moreover, the IVSA cyclic runs highlighted the excellent regeneration capability and stability of both Fe20/ZIF‐7‐P and Fe20/13X‐M with Fe20/13X‐M exhibiting ethylene purity, recovery, and productivity of 99.4%, 99.6%, and 39.9 mol/kg.h, respectively. Overall, these findings underscore the potential of the hybrid induction/vacuum process as an effective technique for achieving efficient regeneration of sorbents in olefin/paraffin separation. [ABSTRACT FROM AUTHOR]

Autoclave corrosion testing has been used for many years; however, few have studied the effect of its shortcomings on the formation of corrosion products and corrosion behaviour. In particular, understanding of these effects under high temperature and high pressure (HTHP) is rare. In this study, we highlighted the important parameters such as heating periods, flow rates and volume-to-surface ratios influencing carbon steel corrosion in the early stages. Especially, characterisation and protection behaviour of corrosion products associated with corrosion behaviour in the heating stage under the geothermal CO2-containing environment were systematically studied via mass loss, in-situ electrochemistry and surface analysis techniques. The roles of pCO2, volume-to-surface ratio and flow rate influence the formation of the corrosion products in the early stage are also evaluated.

Methylene blue pollutants can be treated by photocatalytic methods using metal oxide-based semiconductor materials and metal organic framework (MOF). These two materials are often coupled into a composite to improve their physicochemical properties and catalytic activity. This research focuses on the synthesis of composites based on Cr-PTC MOF, ZnO, and Fe3O4 by the sonochemical method. The obtained composites were characterized and tested for catalytic activity in methylene blue pollutant degradation in an aqueous system under acidic conditions (pH = 5). Our investigation shows that the Cr-PTC@Fe3O4 composite possesses the lowest band gap energy of 1.86 eV and achieves the highest photocatalytic activity in methylene blue degradation at solution pH = 5, with a percent degradation of 84.36%. The sonochemical incorporation of Fe3O4 and Cr-PTC MOF is able to fabricate materials in a short time with better photocatalytic activity in degrading methylene blue than the single materials. Copyright © 2024 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Abstract Today, high-energy applications are devoted to boosting the storage performance of asymmetric supercapacitors. Importantly, boosting the storage performance of the negative electrodes is a crucial topic. Fe3O4-based active materials display a promising theoretical storage performance as a negative electrode. Thus, to get a high storage performance of Fe3O4, it must be tailored to have a higher ionic and electronic conductivity and outstanding stability. Functionalized graphite felt (GF) is an excellent candidate for tailoring Fe3O4 with a facile ionic and electronic pathway. However, the steps of the functionalization of GF are complex and time-consuming as well as the energy loss during this step. Thus, the in-situ functionalization of the GF surface throughout the synthesis of Fe3O4 active materials is proposed herein. Fe3O4 is electrodeposited at the in-situ functionalized GF surface with the crystalline nanowires-like structure as revealed from the various analyses; SEM, TEM, Mapping EDX, XPS, XRD, wettability test, and Raman analysis. Advantageously, the synthetic approach introduces full homogeneous and uniform coverage of the large surface area of the GF. Thus, Fe3O4 nanowires with high ionic and electronic conductivity are characterized by a higher storage performance. Interestingly, Fe3O4/GF possesses a high specific capacity of 1418 mC cm−2 at a potential scan rate of 10 mV s−1 and this value retained to 54% at a potential scan rate of 50 mV s−1 at an extended potential window of 1.45 V. Remarkably, the diffusion-controlled reaction is the main contributor of the storage of Fe3O4/GF electrode as revealed by the mechanistic studies.

AbstractThis study investigates the production of TiO2/Fe3O4/C hydrophilic magnetic nanocomposites produced via a one-step novel method using the submerged arc discharge method applied in liquid media of ethanol and ethanol–ammonia under the influence of external magnetic field. The magnetized submerged arc discharge forms a longer-lasting plasma arc, thereby affecting the growth of spherical and tubular carbon nanocomposites. More reactive species enrolled in the carbon growth in the magnetized submerged arc discharge, resulting in the ordered crystalline structure. The nanocomposites synthesized in ethanol–ammonia show hydrophilic characteristics, indicated by their dispersion improvement in the water and the presence of the vibrations of hydroxyl, amine, and –CN functional groups in Fourier transfer infrared (FTIR) spectra. The preparation technique described in this study using magnetized submerged arc discharge is supposed to be a simple and less costly preparation method that can potentially be further applied to produce numerous other nanocomposites.

We propose here a fabrication of an electrochemical sensor to detect heavy metal ions based on a glass carbon electrode (GCE) modified with a composite system consisting of graphene, chitosan, and Fe3O4 nanoparticles (GrCF) by using square wave voltammetry (SWV) measurements. The GrCF composite was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Raman spectroscopy. GrCF consists of thin and smooth sheets stacked in overlapping layers to form porous structures. In the GrCF composite, graphene acts as a substrate with a high electrochemical activity and a good electrical conductivity, Fe3O4 nanoparticles are uniformly distributed on the graphene thanks to chitosan as a binder, the functional groups of chitosan (− OH, − NH2) have the ability to form complexes with heavy metal ions, and the excellent adsorption capacity of Fe3O4 nanoparticles has enhanced the electrochemical reactions. The GrCF/GCE can detect Pb2+ ions with a linear range from 4 to 16 μM, a low detection limit of 3.57 μM, and a sensitivity of 8.623 μA μM−1. Furthermore, the repeatability of the measurements are reliable with a standard deviation (SD) of 0.15 μA and a relative standard deviation (RSD%) of 4.16%. Additionally, Pb2+ was detected in the real sample at potentials of − 0.50 V/ − 0.52 V with calculated recovery values for two measurements of 89.02% and 89.43%. The electrode modification method based on the GrCF composite promises outstanding advantages in the field of electrochemical sensors for detection of heavy metal ions. [ABSTRACT FROM AUTHOR]

In the current study, a novel composite (Fe3O4@MnO2@Al2O3) was prepared to remove crystal violet dye and cadmium from aqueous solutions. The coprecipitation method was utilized to synthesize the composite. Batch studies are carried out using a contact period of (0.5-3) hours, an initial crystal violet and cadmium content of (50-200) mg/L, an agitation speed of (50-200) rpm, a pH of (4-12), and a composite dosage of (0.2-1) g per 50 mL of contaminated solution. The isotherm and kinetics models are formulated the experimental data. XRD, SEM-EDS, and FTIR analysis were utilized for composite characterization. The results revealed that the removal efficacy of crystal violet dye was 99.311% at 1 g of adsorbent, pH 12, 50mg/L, 1 hour, and 200rpm. The removal efficacy for cadmium (Cd) is 99.7296% at 1 g of sorbent mass at pH 6, 50mg/L, 1 hour, and 200rpm. The outcomes demonstrated that the Langmuir model could accurately depict the sorption of crystal violet dye onto the composite with R2 (0.9882) and SSE (0.7084). Based on Freundlich, the composite's capacity to reflect cadmium sorption was assessed by its highest R2 (0.8947) and lowest SSE (8.5149). The pseudo-second-order model is a more realistic way to explain how cadmium and crystal violet dye sorb onto the composite. The results showed that the composite is effective in eliminating target pollutants, since cadmium has a maximum adsorption capacity of 48.5052 mg/g and crystal violet dye has a capacity of 40.9682 mg/g. Therefore, (Fe3O4@MnO2@Al2O3) can be used as efficient sorbent for removing Cd and crystal violet dye from synthetic industrial wastewater.

Abstract Cancer stands as one of the most impactful illnesses in the modern world, primarily owing to its lethal consequences. The fundamental concern in this context likely stems from delayed diagnoses in patients. Hence, detecting various forms of cancer is imperative. A formidable challenge in cancer research has been the diagnosis and treatment of this disease. Early cancer diagnosis is crucial, as it significantly influences subsequent therapeutic steps. Despite substantial scientific efforts, accurately and swiftly diagnosing cancer remains a formidable challenge. It is well known that the field of cancer diagnosis has effectively included electrochemical approaches. Combining the remarkable selectivity of biosensing components—such as aptamers, antibodies, or nucleic acids—with electrochemical sensor systems has shown positive outcomes. In this study, we adapt a novel electrochemical biosensor for cancer detection. This biosensor, based on a glassy carbon electrode, incorporates a nanocomposite of reduced graphene oxide/Fe3O4/Nafion/polyaniline. We elucidated the modification process using SEM, TEM, FTIR, RAMAN, VSM, and electrochemical methods. To optimize the experimental conditions and monitor the immobilization processes, electrochemical techniques such as CV, EIS, and SWV were employed. The calibration graph has a linear range of 102–106 cells mL−1, with a detection limit of 5 cells mL−1.

The core-shell structure Fe3O4@C magnetic nanoparticles were synthesized with superparamagnetic Fe3O4 nanosphere as a magnetic core, and soluble starch resin as a carbon source via a solvothermal method. Silica-iron oxide and Fe3O4@C carriers with a core-shell structure were prepared by carbonization of organic material on the surface of Fe3O4 nanoparticles, Fe3O4@C supported Pd were processed into magnetic nano-catalysts with core-shell structure, and their catalytic properties were investigated. The resulting environmentally friendly magnetic material can be used to degrade dye wastewater. The structure of magnetic nanoparticles was characterized using TEM, XRD and VSM. The effects of preparation conditions in the structure of the Fe3O4@C magnetic nanoparticles were taken out. The results indicate that from XRD, the magnetic nano particles Fe3O4@C synthesized of carbon sources have amorphous carbon diffraction peak except for all the characteristic peaks of Fe3O4. The saturation magnetization Fe3O4, Fe3O4@SiO2 and Fe3O4@C – 59.14 emu/g, 49.12 emu/g and 27.95 emu/g, respectively.

The iron (III) Schiff base complex was immobilized on magnetic silica as well as mesoporous silica substrates and characterized by XRD, TEM, FT-IR, AAS, VSM techniques, and in the case of mesoporous silica, it was also identified with N2 adsorption/desorption and TGA methods. These materials were applied for oxidation of benzyl alcohols and sulfides with hydrogen peroxide as a green oxidant. The effect of catalyst structures was studied in the mentioned reactions. The results showed that using of mesoporous silica in the oxidation of sulfides and benzyl alcohols with hydrogen peroxide in the optimal reaction conditions provided a higher catalytic yield in the same or even less reaction time, The higher catalytic performance of the mesoporous substrate based on the identifications (carried out by N2 adsorption/desorption technique) can be attributed to the higher surface area of this substrate and the stronger connection of the Schiff base complex of iron (III) to the mesoporous silica (according to leaching test).

The activated persulfate (PS) process could produce sulfate radical (SO4·-) and rapidly degrade organic pollutants. The application of Fe3O4 as a promising PS activator was limited due to the rapid conversion of Fe2+ to Fe3+ on its surface. Mo4+ on MoS2 surface could be used as a reducing site to convert Fe3+ to Fe2+, but the separation and recovery of MoS2 was complex. In this study, MoS2/Fe3O4 was prepared to accelerate the Fe3+/Fe2+ cycle on Fe3O4 surface and achieved efficient separation of MoS2. The results showed that MoS2/Fe3O4 was more effective for PS activation compared to Fe3O4 or MoS2, with a removal efficiency of 91.8% for 20 mg·L−1 tetracycline (TC) solution under the optimal conditions. Fe2+ and Mo4+ on MoS2/Fe3O4 surface acted as active sites for PS activation with the generation of SO4•−, •OH, •O2−, and 1O2. Mo4+ acted as an electron donor to promote the Fe3+/Fe2+ cycling and thus improved the PS activation capability of MoS2/Fe3O4. The degradation pathways of TC were inferred as hydroxylation, ketylation of dimethylamino group and C-N bond breaking. This study provided a promising activated persulfate-based advanced oxidation process for the efficient degradation of TC by employing MoS2/Fe3O4 as an effective activator. HIGHLIGHTS MoS2/Fe3O4 was an effective, recoverable PS activator for tetracycline degradation.; TC was removed by free radical and non-free radical degradation pathways.; Mo4+ promoted the regeneration of Fe2+ on the Fe3O4 surface.;

Abstract The challenges in water treatment include the need for efficient removal of pollutants like nitrate, which poses significant environmental and health risks. Alumina's significance lies in its proven effectiveness as an adsorbent for nitrate removal due to its high surface area and affinity for nitrate ions. This study delves into the synthesis of differen nano-sized γ-alumina (γA1-5) employing diverse precursors and methods, including nepheline syenite, lime, aluminum hydroxide, precipitation, and hydrothermal processes at varying reaction times. Simultaneously, magnetite (Fe3O4) nanoparticles and magnetite/γ-alumina nanocomposites (Fn/γA5) were synthesized using the co-precipitation method with varying weight ratios (n). Our primary objective was to optimize γ-alumina synthesis by comparing multiple methods, shedding light on the influence of different precursors and sources. Hence, a comprehensive adsorption study was conducted to assess the materials’ efficacy in nitrate removal. This study fills gaps in the literature, providing a novel perspective through the simultaneous assessment of magnetite/alumina nanocomposites and pure alumina performance. Structural and morphological properties were studied employing XRD, FT-IR, FESEM, EDX, XRD, and VSM techniques. The conducted experiments for γA5, F5/γA5, and F10/γA5 nanocomposites showcased the optimum pH of 5 and contact time of 45 min for all samples. The influence of nitrate’s initial concentration on the removal percentage was investigated with initial concentrations of 10 ppm, 50 ppm, and 100 ppm. γA5, F5/γA5 and F10/γA5 nanocomposites had 17.3%, 55%, and 70% at 10 ppm, 18%, 55.16%, and 74% at 50 ppm, and 8.6%, 53.1%, and 63%, respectively. The results highlighted that F10/γA5 can be used as a remarkable adsorbent for wastewater treatment purposes.

Due to the complexity of the actual polluted water components, the development of efficient and economical multifunctional materials has great significance and value in the remediation of polluted water. In this study, we have employed MoS2 nanosheets as a carrier to sequentially load magnetic Fe3O4 and ZnO nanoparticles via the electrostatic interaction, yielding a three-in-one MoS2/Fe3O4/ZnO (MFZ) composite nanosheet. The prepared MFZ could catalyze the conversion of H2O2 into hydroxyl radicals (•OH), induce intracellular oxidative stress in situ by nanosized ZnO or Zn2+, and produce photonic hyperpyrexia to promote the catalytic generation of •OH. In vitro antibacterial assays demonstrated that MFZ had high-performance multimodal elimination against Escherichia coli and Staphylococcus aureus in the presence of H2O2 and an 808 nm laser. Moreover, MFZ could also catalyze the rapid degradation of organic pollutants in water including tetracycline (TC), methylene blue (MB), Congo red (CR), methyl orange (MO), and rhodamine B (RhB), which was mainly attributed to the strong oxidization of •OH. Not surprisingly, MFZ displayed satisfactory capacity for killing pathogenic bacteria and removing organic pollutants in real polluted water samples, and importantly, the MFZ could be efficiently recovered by applying an external magnetic field. Therefore, the magnetically recoverable MFZ composite nanomaterial proposed in this work is a versatile and sustainable alternative for future water disinfection and purification. [ABSTRACT FROM AUTHOR]

In this study, the optimization and characterization of NiFe2O4/Polyhydroxymethyl methacrylate (NF-pHEMA) and Fe3O4/Polyhydroxymethyl methacrylate (M-pHEMA) magnetic nanogel structures were carried out and the usability of these magnetic nanogels for the immobilization of lipase enzyme was investigated. Fe3O4/pHEMA (M-pHEMA) nanogel and NiFe2O4/pHEMA (NF-pHEMA) nanogel structures were produced by the photochemical method. The characterization of these materials was performed by FTIR, SEM, AFM analysis. Then, the lipase enzyme was immobilized on magnetic nanogels by adsorption and after that cross-linking method under optimum conditions. For the characterization of lipase immobilized magnetic nanogels; optimum temperature, thermal stability, optimum pH, pH stability, reusability and kinetic parameters were investigated and nature and immobilized lipase were compared. It was observed that there was a significant improvement in the thermal and pH stability of the immobilized enzyme compared to the free enzyme. Lipase-immobilized M-pHEMA lost 50% of its activity after 15 uses and after 16 uses of lipase-immobilized NF-pHEMA. The results show that immobilization to the synthesized magnetic nanogels provides an improvement in the properties of the lipase enzyme. It is thought that the synthesized magnetic nanogels can be an alternative for different applications, especially drug delivery systems. [ABSTRACT FROM AUTHOR]

We investigated the debonding on-demand (DoD) of adhesively bonded hybrid dissimilar joints by applying electromagnetic induction heating to the joint overlap section, wherein the epoxy resin is reinforced with iron oxide (Fe3O4) particles. Ti-6Al-4 V adherends were bonded with CFRP or GFRP adherends using neat/modified epoxy adhesive. DoD tests revealed that eddy current heating of Ti-6Al-4 V was a dominant heating mechanism of the joints while both eddy current and magnetic hysteresis of CFRP and Fe3O4 acted as a secondary heating factor. A low content Fe3O4 and thinner composite adherend reduced the time to failure of the joints. Likewise, CFRP required a shorter time for debonding compared to GFRP due to its electromagnetic properties. Modifications with 2 and 5 wt.% Fe3O4 for CFRP and GFRP joints led to 31% and 37% time reduction which will be crucial for energy-saving when debonding large structures. Remarkably, sandblasting improved the electromagnetic induction capabilities of Ti-6Al-4 V, leading to a notable increase in the heating rate, which jumped from around 20°C/s to 80°C/s. Sandblasting enhanced the surface roughness of the adherends but only the water contact angle of GFRP decreased considerably. Fe3O4 modifications increased the epoxy residue on the Ti-6Al-4 V surface from 26% to 99%. DIC revealed the strain distribution of bulk materials to understand the thermomechanical mismatches between the materials and the adhesive joints exhibited high peel stresses at the overlap ends. The low weight content (2 and 5 wt.%) of Fe3O4 exhibited beneficial effects on the mechanical, thermal, thermomechanical, wettability and lap shear strength. [ABSTRACT FROM AUTHOR]

In order to solve the problem of demulsification of oil-water emulsion, a new type of highly efficient and recyclable magnetic fluorine-containing polyether composite demulsifier (Fe3O4@Ti-F) was synthesized. Fe3O4@Ti-F was prepared by one-pot method to combine magnetic nanomaterial TiO2 with Fe3O4 and graft fluorinated polyether. The successful synthesis of Fe3O4@Ti-F was confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction (XPS). The demulsification performance of Fe3O4@Ti-F was evaluated by using the self-made crude oil emulsion as the experimental object. The demulsification mechanism of the demulsifier and the influence of external factors such as temperature and pH on the demulsification performance of the demulsifier were discussed, and the amount of TiO2 in the preparation process was determined. The results show that the demulsification efficiency of 50:50 (v/v %) W/O emulsion can reach 90.83% when the dosage of Fe3O4@Ti-F is 600 mg/L, the temperature is 65 °C and the time is 30 min. In the neutral acid environment, the demulsification rate of the demulsifier is above 80%. In addition, Fe3O4@Ti-F has been proved to have good magnetic effect. Under the action of external magnetic field, it can be recovered and recycled from the two-phase system for 4 times, and its demulsification efficiency is still above 60%. Fe3O4@Ti-F will have broad application prospects in the field of oil-water separation in an energy-saving way. [ABSTRACT FROM AUTHOR]

In the present study, cellulose@SP@catechin@Fe3O4 nanocomposite underwent synthesis and characterization employing various analytical techniques, including Fourier transform‐infrared spectroscopy (FT‐IR), field‐emission scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller analysis, thermogravimetric analysis, vibrating sample magnetometry, X‐ray powder diffraction, and X‐ray spectroscopy. This reusable and efficient nanocomposite facilitated the synthesis of azo‐linked 4‐arylidene‐benzodiazepine, resulting in products with high yields. Characterization of these products was conducted utilizing 1H nuclear magnetic resonance (NMR), 13C NMR, and FT‐IR spectral data alongside mass analyses. Additionally, their antioxidant activities were assessed via 1,1‐diphenyl‐2‐picrylhydrazyl analysis. [ABSTRACT FROM AUTHOR]

In the current study, a novel composite (Fe3O4@MnO2@Al2O3) was prepared to remove crystal violet dye and cadmium from aqueous solutions. The coprecipitation method was utilized to synthesize the composite. Batch studies were carried out using a contact period of 0.5-3 hours, an initial crystal violet and cadmium content of 50-200 mg/L, an agitation speed of 50-200 rpm, a pH of 4-12, and a composite dosage of 0.2-1.0 g per 50 mL of contaminated solution. The isotherm and kinetics models were formulated the experimental data. XRD, SEM-EDS, and FTIR analyses were utilized for composite characterization. The results revealed that the removal efficacy of crystal violet dye was 99.311% at 1 g of adsorbent, pH 12, 50 mg/L, 1 hour, and 200 rpm. The removal efficacy for cadmium (Cd) is 99.7296% at 1 g of sorbent mass at pH 6, 50 mg/L, 1 hour, and 200 rpm. The outcomes demonstrated that the Langmuir model could accurately depict the sorption of crystal violet dye onto the composite with R² (0.9882) and SSE (0.7084). On the basis of Freundlich, the capacity of the composite to reflect cadmium sorption was assessed by its highest R² (0.8947) and lowest SSE (8.5149). The pseudo-second-order model is a more realistic way to explain how cadmium and crystal violet dye sorb onto the composite. The results showed that the composite is effective in eliminating target pollutants, since cadmium has a maximum adsorption capacity of 48.5052 mg/g and crystal violet dye has a capacity of 40.9682 mg/g. Therefore, (Fe3O4@MnO2@Al2O3) can be used as efficient sorbent for removing Cd and crystal violet dye from synthetic industrial wastewater. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) was obtained by the improved Hummers method. The GO/Fe3O4 composite, in which GO was combined with magnetic Fe3O4 nanoparticles, was prepared by co-precipitation method. The crystalline structure, microscopic morphology, magnetic properties and drug loading of the composite were analyzed. The results showed that: The GO/Fe3O4 composite had high crystallinity; GO doping improved the uniformity of Fe3O4 particles, and the grain size of GO/Fe3O4 composite was 13-15 nm. The GO/Fe3O4 composite exhibited superparamagnetic properties with a slight decrease in saturation magnetization. The drug-release properties were studied by using GO/Fe3O4 composite to load doxorubicin (DOX). The average encapsulation efficiency of GO/Fe,O4/DOX inclusion complex was 62.24%, which was quite high. The drug release showed pH dependence. When the pH was 7.4, the cumulative release rate reached 73.3% in 75 h. The cellular uptake test showed that the GO/Fe3O4 carrier had certain targeting properties and could be used as a good new drug carrier. [ABSTRACT FROM AUTHOR]

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Due to wear and improper operation, many machine parts become useless, which is why issues of friction and wear remain constantly relevant across all industrial sectors. This paper presents the results of research on the microstructure and properties of a nanostructural composite coating containing solid lubricant. The coating was deposited from a mixture of nanostructural WC-12Co powder and nanostructural Fe3O4 powder using HVOF spraying. Despite significant differences in grain size and density of both powders, the deposited coating consisted of WC-12Co matrix containing evenly distributed Fe3O4. The XRD analysis of the coating confirmed the presence of both components and the presence of W2C, which resulted from the decarburization of WC due to the high temperature during the spraying process. Furthermore, the microstructure analysis of the coatings confirmed that they contained both nanostructural WC and Fe3O4 grains that were present in the feedstock. The coefficients of friction, microhardness, and wear of the nanostructured composite coatings were determined using an experimental binomial program. Based on the ANOVA conducted, it was determined that the most significant impact on the friction coefficient is the Fe3O4 content in the sprayed mixture, while the oxygen to propane ratio affects the microhardness. For the wear of nanostructural composite coatings, the most important parameter is the spraying distance. [ABSTRACT FROM AUTHOR]

Cu2+ has increasingly become a great threat to the natural environment and human health due to its abundant content and wide application in various industries. DL-Mercaptosuccinic acid and ZnS-modified Fe3O4 nanocomposites were designed, synthesized, and applied in the determination of Cu2+. The prepared nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopes (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and thermogravimetric analyzer (TG). The magnetic fluorescent nanoprobe exhibited highly selective and sensitive fluorescence-quenching characteristics with Cu2+ ions. The fluorescence detection linear range was 0–400 μM, with the detection limit being 0.489 μM. In addition, the magnetic fluorescent nanoprobe exhibited a high adsorption and removal rate for Cu2+. It had been successfully applied to detect Cu2+ in real water samples with a satisfactory recovery rate. The magnetic fluorescent nanoprobe could simultaneously realize the functions of enrichment, quantitative detection, and separation, reduce the pollution of copper ions and probes, and establish an environment-friendly detection method. Consequently, the magnetic fluorescent nanoprobe offered a new pathway for the removal and detection of not only Cu2+ but also other heavy metal ions in water. [ABSTRACT FROM AUTHOR]

Fe4O3 has shown great potential as an enhancer of batch anaerobic digestion performance. In this study, the effect of two types of Fe3O4 additive utilization strategies (magnetic separation recycling strategy and replenishment without recycling strategy) on semi-continuous anaerobic co-digestion of sludge and corn straw were investigated. A maximum methane yield of 163.88 ± 12.18 mL/g·VS·d was obtained at the dosage of 10 g/kg Fe3O4 with magnetic separation recycling strategy compared to the control without the addition of Fe3O4. As compared to the replenishment strategy, the recycling strategy improved specific daily methane yields by 38.45% and 45.75% for Fe3O4 addition amounts of 5 g/kg and 10 g/kg, respectively. The results show that the recycling of Fe3O4 additives can further optimize the composition of VFAs. Although the total VFAs were not elevated, the proportion of acetic acid increased and the proportion of propionic acid as well as butyric acid decreased. The present research supports the magnetic recycling of Fe3O4 as a new strategy to solve the problem of additive loss in semi-continuous anaerobic digestion process. [ABSTRACT FROM AUTHOR]

The immune checkpoint blockade strategy has improved the survival rate of late‐stage lung cancer patients. However, the low immune response rate limits the immunotherapy efficiency. Here, we report a ROS‐responsive Fe3O4‐based nanoparticle that undergoes charge reversal and disassembly in the tumor microenvironment, enhancing the uptake of Fe3O4 by tumor cells and triggering a more severe ferroptosis. In the tumor microenvironment, the nanoparticle rapidly disassembles and releases the loaded GOx and the immune‐activating peptide Tuftsin under overexpressed H2O2. GOx can consume the glucose of tumor cells and generate more H2O2, promoting the disassembly of the nanoparticle and drug release, thereby enhancing the therapeutic effect of ferroptosis. Combined with Tuftsin, it can more effectively reverse the immune‐suppressive microenvironment and promote the recruitment of effector T cells in tumor tissues. Ultimately, in combination with α‐PD‐L1, there is significant inhibition of the growth of lung metastases. Additionally, the hyperpolarized 129Xe method has been used to evaluate the Fe3O4 nanoparticle‐mediated immunotherapy, where the ventilation defects in lung metastases have been significantly improved with complete lung structure and function recovered. The ferroptosis‐enhanced immunotherapy combined with non‐radiation evaluation methodology paves a new way for designing novel theranostic agents for cancer therapy. [ABSTRACT FROM AUTHOR]

In this study, a constructed wetland–Fe3O4/granular activated carbon anode microbial electrolysis cell (CW-FMEC) was constructed to enhance denitrification in low COD/N ratio wastewater. The introduction of Fe3O4 boosted the expression of functional genes involved in the denitrification pathway, and the abundance of narG, nirS, and nosZ increased by 99.29%, 70.54%, and 132.18%, respectively, compared to CW. In addition, the content of c-type cytochromes (c-Cyts) and EPS were also enhanced in the CW-FMEC. The microbial communities study displayed that Thauera, Dechloromonas, and Arenimonas became the main genera for denitrification. The denitrification performance at different COD/N ratios was investigated in depth. Under optimal working circumstances, the CW-FMEC had an excellent nitrate removal rate (88.9% ± 1.12%) while accumulating nearly no NO2−-N or NH4+-N in the effluent. This study provides a new direction for the development of CW-MEC and accelerates its implementation. [ABSTRACT FROM AUTHOR]

Graphene‐loaded triiron tetraoxide/silicone‐rubber composites containing highly loaded graphene‐loaded Fe3O4 (Fe3O4@RGO) particles were fabricated using static magnetic field‐induced alignment. The Fe3O4@RGO particles were characterized through Fourier transform infrared, x‐ray diffraction, SEM, and XPS analyses. Subsequently, the influence of added material and the strength of the magnetic field on the alignment distribution of the filler were examined through a synergistic combination of SEM and Raman spectroscopy. The electrical conductivity and electromagnetic shielding properties of the composites were assessed. The electrical conductivity of the composites increased with increasing filler addition, the 25 wt% filler mixture had the fastest curing rate and the maximum torque, and the continued increase in filler addition led to the occurrence of many defects. Concurrently, the alignment distribution of the filler progressively enhances with the augmentation of magnetic field strength. The composites synthesized at 180 mT exhibit the most substantial alignment, facilitating the establishment of effective conductive pathways. This results in a notable enhancement in electromagnetic shielding effectiveness, approximately 400% greater than that of pure silicone rubber and around 40% higher than that of non‐aligned composites. This approach introduces a novel concept for shaping the structural design of flexible electromagnetic shielding materials. Highlights: Highly loaded Fe3O4@RGO was prepared by self‐assembly.The continuous phase structure of Fe3O4@RGO oriented was assessed.Fully oriented Fe3O4@RGO promotes the formation of conductive pathways.Fully oriented Fe3O4@RGO reduced the SER by 13% and increased the SEA by 67%. [ABSTRACT FROM AUTHOR]

• A series of novel chitosan-based magnetic flocculants was prepared by molecular structure control. • Fe 3 O 4 @SiO 2 @CTS-P(AM-DMC) can effectively removal turbidity from 200 to 2000 NTU. • Magnetic flocs form eddy currents and experience acceleration, stabilization, and deceleration stages. • Charge neutralization was dominant under acidic and neutral conditions, while adsorption and bridging effects play an important role in alkaline environments. A series of novel chitosan-based magnetic flocculants FS@CTS-P(AM-DMC) was prepared by molecular structure control. The characterization results showed that FS@CTS-P(AM-DMC) had a uniform size of about 21.46 nm, featuring a typical core-shell structure, and the average coating layer thickness of CTS-P(AM-DMC) was about 5.03 nm. FS@CTS-P(AM-DMC) exhibited excellent flocculation performance for kaolin suspension, achieved 92.54% turbidity removal efficiency under dosage of 150 mg/L, pH 7.0, even at high turbidity (2000 NTU) with a removal efficiency of 96.96%. The flocculation mechanism was revealed to be dominated by charge neutralization under acidic and neutral conditions, while adsorption and bridging effects play an important role in alkaline environments. The properties of magnetic aggregates during flocculation, breakage, and regeneration were studied at different pH levels and dosages. In the process of magnetophoretic, magnetic particles collide and adsorb with kaolin particles continuously due to magnetic and electrostatic attraction, transform into magnetic chain clusters, and then further form three-dimensional network magnetic aggregates that can capture free kaolin particles and other chain clusters. Particle image velocimetry confirmed the formation of eddy current of magnetic flocs and experienced three stages: acceleration, stabilization, and deceleration. [Display omitted] [ABSTRACT FROM AUTHOR]