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The manufacture, modification, and application of surface-functionalized Fe3O4 nanoparticles in the extraction and isolation of antibiotics are reviewed in this paper. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) can be used to characterize the morphological features of Fe3O4 nanoparticles, while Fourier Transform Infrared Spectrometer (FTIR) and X-ray diffractometry (XRD) can be used to determine the crystalline shapes and distinctive functional groups of these particles. We gathered a lot of data to investigate the effects of experimental parameters like pH, adsorbent dosage, contact time, and ionic strength on the extraction of antibiotics from Fe3O4 magnetic nanoparticles. We additionally talked about the mechanism of action of magnetic nanoparticles for the extraction of separated antibiotics and how they are utilized in practical detection methods. This work concluded with an overview of the potential for environmental friendliness and dispersion of functionalized Fe3O4 nanoparticles, as well as potential challenges and directions. [ABSTRACT FROM AUTHOR]

High amounts of dyes in receiving waters are dangerous to the ecosystem due to their specific properties, such as high alkalinity, high organic compound content, and robust structure. The present article aims to investigate the efficiency of the Fe3O4/zeolite process in removing methylene blue dye (MB) from aqueous solutions, as well as to optimize the factors influencing the efficiency of removal. Initially, a Fe3O4/zeolite nanocomposite was prepared and characterized using Fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) techniques. The impact of various parameters such as pH of the aqueous solution, nanocomposite dosage, contact time, and initial dye concentration on the adsorption efficiency was systematically investigated. FTIR shows presence of iron disrupts the hydrogen bonds in the zeolite structure. Additionally, SEM analysis reveals the pronounced microporosity of the Fe3O4/zeolite nanocomposite. Optimal conditions were determined to be a pH of 9.0, an adsorbent dosage of 0.75 g/L, a contact time of 45 min, and a methylene blue concentration of 50 mg/L, resulting in a removal efficiency of 96.92%. Adsorption isotherm and kinetic studies revealed that the adsorption process of methylene blue followed the Freundlich isotherm (R2 > 0.984) and pseudo-second-order kinetic models (R2 > 0.9958), respectively. The qm (sorption capacity) of the Fe3O4/zeolite nanocomposite was 113.64 mg/g. Furthermore, the reusability of the adsorbent was assessed through five consecutive experiments, demonstrating only a marginal decrease (approximately 7.9%) in methylene blue removal efficiency. These findings underscore the potential of the magnetic nanocomposite based on zeolite as a highly effective adsorbent for methylene blue removal applications.Highlights: A zeolite-based magnetic nanocomposite was synthesized and characterized using FT-IR and SEM techniques for the removal of methylene blue dye from water. The study determined optimal conditions for dye removal as a pH of 9.0, an adsorbent dosage of 0.75 g/L, a contact time of 45 min, and an initial dye concentration of 50 mg/L, achieving a removal efficiency of 96.92%. The adsorption process followed the Freundlich isotherm and pseudo-second-order kinetic models, with high correlation coefficients (R2 > 0.984 and R2 > 0.9958, respectively). The adsorbent demonstrated good reusability with only a 7.9% decrease in removal efficiency over five consecutive uses, highlighting its effectiveness for repeated applications. [ABSTRACT FROM AUTHOR]

A microbial fuel cell (MFC) is a modern, environmentally friendly, and cost-effective energy conversion technology that utilizes renewable organic waste as fuel, converting stored chemical energy into usable bioelectricity in the presence of a biocatalyst. Despite advancements in MFC technology, several challenges remain in optimizing power production efficiency, particularly regarding anode materials and modifications. In this study, low-cost biosynthesized iron oxide nanoparticles (Fe3O4 NPs) were coated with a polyaniline (PANI) conducting matrix to synthesize hybrid Fe3O4/PANI binary nanocomposites (NCs) as modified MFC anodes via an in-situ polymerization process. Characterization techniques, including UV–Vis, XRD, SEM, and FT-IR, revealed the successful synthesis of green-routed nano-scaled materials with altered optical properties after matrix coating, high crystallinity in the iron oxide phase, rougher surface morphology, and characteristic Fe–O peaks at 594 cm⁻1. Additionally, the electrochemical behavior of the prepared nano-materials was characterized by cyclic voltammetry (CV), where low ΔEp values (0.473 V) for Fe3O4/PANI NCs indicated the presence of reversible charge transfer mechanisms at the electrode surface, reflecting a high rate of electron transfer. The synthesized nanocomposite was used to modify pencil graphite anodes to construct four single-chamber MFCs: bare pencil graphite anodes, pencil graphite anodes modified with Fe3O4, PANI, and Fe3O4/PANI nanocomposites. The maximum open circuit voltage (OCV) value was 645 ± 24.50 mV, with a high power output of 424.51 ± 6.86 mW/m2 and current density of 2475.01 ± 1.23 mA m−2 produced by the Fe3O4/PANI NCs modified pencil graphite electrode, which is more than six times the efficiency in terms of power density compared to the unmodified pencil graphite electrode (PGE). These results demonstrate that the synthesized nanocomposite plays an effective and value-added role in modifying traditional carbon anode electrodes within an MFC energy conversion device system. [ABSTRACT FROM AUTHOR]

To further enhance the safety and energy efficiency of the Fe3O4 preparation experiment, we proposed a strategy for synthesizing monodisperse Fe3O4 microspheres through a one-step solvothermal process. In this environmentally friendly synthesis method, stable FeCl3∙6H2O was utilized as the sole raw material, while ethylene glycol, characterized by its high boiling point and favorable safety profile, served as the solvent. Additionally, inexpensive and readily available urea was selected to function either as a mineralizer or surfactant. Through this one-step solvothermal reaction, the target product of Fe3O4 could be obtained without subsequent calcination under reducing or inert atmospheres, thereby enhancing experimental safety and promoting energy conservation. By controlling the amount of urea added, it became feasible to produce monodisperse magnetic Fe3O4 microspheres characterized by complete crystallinity and high yield. Utilizing the as-synthesized Fe3O4 as a catalyst, we investigated its photocatalytic activity against xylenol orange organic dyes along with its regeneration characteristics. When 40 mmol of urea was incorporated into the reaction mixture, the resulting Fe3O4 sample exhibited optimal photocatalytic performance; a 20 mg/L xylenol orange solution became colorless and transparent after just 1.5 h of UV light irradiation. Furthermore, during five consecutive regeneration cycles, its catalytic activity could be restored to its initial level. Importantly, Fe3O4 demonstrated excellent magnetic sensitivity properties that facilitated rapid targeted separation under an external magnetic field, providing convenience for recovery and collection purposes. [ABSTRACT FROM AUTHOR]

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Highlights The Janus-type multifunctional ultra-flexible polytetrafluoroethylene-carbon nanotube-Fe3O4/MXene (FCFe/M) membranes were fabricated via a shear-induced in situ fibrillation technique followed by vacuum-assisted filtration. Thanks to the strategic distribution of the MXene conductive reflection layer and the silk-like FCFe electromagnetic wave’s absorption layer, the membranes achieve robust electromagnetic interference shielding and effective antireflection through the absorption-reflection-reabsorption mechanism. The membranes exhibit exceptional thermal management performance, including efficient heat dissipation and electrothermal/photothermal conversion capabilities, further enhancing their promising potential for applications in flexible wearable technologies.

MoS2@Fe3O4 composite was fabricated via two-step hydrothermal method, utilizing cetyltrimethyl ammonium bromide(CTAB) as a soft template, thioacetamide as a sulfur source, and sodium molybdate as a molybdenum source. The morphology and structure of MoS2@Fe3O4 were analyzed by SEM and XRD. The efficiency and mechanism of catalytic degradation of iodoprolol(IPM) by MoS2@Fe3O4/H2O2 system was evaluated. The results showed that Fe3O4 was deposited on the surface of MoS2, and MoS2@Fe3O4 had a uniformly dispersed flower ball structure, which provided more catalytic active sites. Under the conditions of initial pH of 4, MoS2@Fe3O4 dosage of 0.15 g/L, H2O2 concentration of 0.5 mmol/L, and IPM concentration of 5 μmol/L, the degradation rate of IPM by MoS2@Fe3O4/H2O2 system reached 89.85% after 30 minutes of reaction. Compared with Fe3O4/H2O2 system, the degradation rate of IPM increased by about 12%. The applied magnetic field facilitated the reusability of MoS2@Fe3O4. The main active species for IPM degradation by the MoS2@Fe3O4/H2O2 system were ·OH and 1O2. The degradation rate of the MoS2@Fe3O4/H2O2 system on IPM remained stable over 80% after 6 cycles, suggesting that MoS2@Fe3O4 had good stability.

[Display omitted] • The use of the Fe 3 O 4 @C 3D electrode for efficient degradation of the MB. • Na 2 S 2 O 3 electrolyte optimised the Fe2+/Fe3+ cycle and extended the applicable pH range of the electrode. • The presence of Na 2 S 2 O 3 reduces iron dissolution and improves the cyclic degradation properties of the material. The cycling rate of iron ions has been reported to limit the Fenton reaction rate. It is, therefore, vital to enhance the cycling rate of iron ions. A composite three-dimensional electrode (FOC) was synthesized using glucose, ammonium carbonate, and FeCl 3 through a combination of hydrothermal synthesis and calcination. The electrode's conditions were subsequently optimized for the applicable pH range and the concentration of methylene blue (MB) that could be effectively degraded. At an FOC-800 dosage of 0.5 g/L, a supply voltage of 4 V, and an initial pH of 4, a degradation rate of 98 % for 10 mg/L MB was achieved, with a 67.5 % reduction in total organic carbon using 2 g/L Na 2 S 2 O 3 as the electrolyte. The material also demonstrated efficacy in degrading both chemical and pharmaceutical wastewater. A comparative analysis using Na 2 SO 4 as the electrolyte confirmed that Na 2 S 2 O 3 effectively promoted the cycling of iron ions, enhancing the degradation performance of FOC and expanding its effective pH range. High-performance liquid chromatography (HPLC) was employed to monitor the concentration changes of S 2 O 3 2- and SO 4 2- during the reaction, while LC-MS was used to identify the degradation products of MB, and ECOSAR was utilized to assess the toxicity of these products. Burst experiments and EPR analysis identified ●OH as the primary active species responsible for degradation, with O 2 ∙ - playing a supporting but not dominant role. [ABSTRACT FROM AUTHOR]

• This is the first report of this catalyst. • Catalysts are used for C N and C C coupling reactions with high activity. • Nanocatalyst can be recovered and reused without decreasing catalytic activity. A Pd Schiff base complex was immobilized onto the surface of magnetic Fe 3 O 4 as a novel, green, and recyclable heterogeneous nanocatalyst and fully characterized by TEM, XRD, FT-IR, BET, SEM, ICP-OES, EDS, TGA, and VSM techniques. The Fe 3 O 4 @SiO 2 @DAA@Schiff base-Pd(0) catalyst exhibits outstanding performance in catalyzing Buchwald-Hartwig and Stille coupling reactions, resulting in high yields of the corresponding products. This catalyst offers numerous benefits, such as a straightforward testing procedure, environmentally friendly reaction conditions, absence of hazardous solvents, quick reaction time, low catalyst usage, and the ability to be reused. Furthermore, the nanocatalyst could be effortlessly separated from the reaction mixture using a bar magnet, enabling its repeated recovery and reuse without compromising its stability or activity. [Display omitted] [ABSTRACT FROM AUTHOR]

• This is the first report of this catalyst. • Nanocatalyst can be recovered and reused without decreasing catalytic activity. • Nanocatalyst characterized by BET, FT-IR, EDS, SEM, TGA, XPS, XRD, ICP, TEM, and VSM technique. The Fe 3 O 4 @L-Threonine-Pd complex, comprising palladium supported on modified Fe 3 O 4 magnetic nanoparticles (MNPs), has been documented for its use in Stille and Suzuki coupling reactions. The catalyst's environmental friendliness was assessed through a range of techniques including vibrating sample magnetometry (VSM), Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma (ICP), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), energy dispersive X-ray photoelectron spectroscopy (XPS), and X-ray spectroscopy (EDS). Using an external magnet, it is easy to separate nanoparticles from the mixture. The nanocatalyst underwent Metal leaching and heterogeneity testing using the ICP-OES technique, demonstrating its ability to be recovered and reused multiple times without a significant loss of catalytic efficiency or palladium leaching. [Display omitted] [ABSTRACT FROM AUTHOR]

This study underscores the potential of nanocomposites of magnetite (Fe 3 O 4) with amine functionalized multi-walled carbon nanotube (MWCNT) for applications in magnetic hyperthermia therapy, by optimizing the amine-functionalized MWCNT concentration to maintain favorable interactions with Fe 3 O 4 , avoiding excessive aggregation, and maximizing the hyperthermia performance. The magnetic property analysis revealed that the presence of amine-functionalized MWCNTs influenced the saturation magnetization (M S) of the nanocomposites, surprisingly, the FC1 (composite with 1 % amine-functionalized MWCNT) and FC3 (composite with 3 % amine-functionalized MWCNT) nanocomposites exhibited higher saturation magnetization (M S) compared to bare Fe 3 O 4 , attributed to the enhanced interaction between Fe 3 O 4 and the amine-functionalized MWCNTs, which facilitated the cationic influx and alignment of surface spins. However, at higher concentrations of functionalized MWCNTs (FC7 and FC10), a reduction in M S was observed, possibly due to aggregation effects which can also be inferred from their cubic anisotropy value. Among the nanocomposites, FC3 exhibited the highest specific absorption rate (SAR), correlating with its enhanced M S , while FC10 showed the lowest SAR, consistent with its reduced M S. The SAR values were found to increase with the applied magnetic field amplitude, with FC3 surpassing bare Fe 3 O 4 at higher field amplitudes, likely due to the predominant effects of Néel relaxation mechanisms. The observed enhancement in magnetic properties at optimal MWCNT concentrations presents a promising pathway for the design of advanced magnetic nanocomposites with improved performance in hyperthermia applications. • Optimized Fe₃O₄/MWCNT nanocomposites enhance magnetic hyperthermia performance. • Amine-functionalized MWCNT improves Fe₃O₄ dispersibility and magnetic properties. • Fe₃O₄ made nanocomposite with 3 wt% amine functionalized MWCNT concentration showed maximum heat generation in magnetic hyperthermia. • High saturation magnetization (M S) achieved with Fe₃O₄/MWCNT composite nanostructures. • Reduced MWCNT aggregation leads to improved magnetic behaviour and therapeutic potential. [ABSTRACT FROM AUTHOR]

Designing efficient and durable HER electrocatalysts for seawater splitting to resist the corrosive seawater is crucial for continuous seawater electrolysis technology. Herein, a self-supported Fe 3 O 4 electrode with P doping and O vacancy (P-Fe 3 O 4-x) was constructed as an efficient and stable HER catalyst under alkaline seawater. A set of characterization reveals that P doping and O vacancy can effectively regulate the local atomic environment of Fe 3 O 4 , optimizing the hydrogen adsorption/desorption of Fe site on P-Fe 3 O 4-x. Moreover, the unique electron-rich local atomic environment of Fe site decreases the adsorption energy of Cl- at the Fe site, remarkably enhance the corrosion-resistance of P-Fe 3 O 4-x. As expected, the obtained P-Fe 3 O 4-x displays high activity (367 mV at 3 A cm−2) and outstanding 1000 h stability in alkaline seawater solution. Besides, the AEM electrolyzer using P-Fe 3 O 4-x as cathode achieves seawater electrolysis of 1.0 A cm−2 at 1.97 V and operates stably for 100 h at the high current density of 1.0 A cm−2. [Display omitted] • The P doping and O vacancy regulate the local atomic environment of Fe 3 O 4. • The P doping and O vacancy facilitate the HER kinetics of Fe site on P-Fe 3 O 4-x. • The P doping and O vacancy remarkably inhibit the adsorption of Cl- on the electrode. • The GGE of AEM using P-Fe 3 O 4-x as cathode has reached the 2026 DOE target. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3DHP Fe 3 O 4 /Fe-N-C was synthesized via hard template, adsorption, pyrolysis. • For cathode: Fe 3 O 4 NPs, abundant Fe-N x and pyridinic N for excellent ORR. • For anode: good biocompatibility and improved anode biomass. • MFCs with 3DHP Fe 3 O 4 /Fe-N-C as anode and cathode: satisfactory performance. The rational development of high-performance anode and cathode electrodes for microbial fuel cells (MFCs) is crucial for enhancing MFC performance. However, complex synthesis methods and single-performance electrode materials hinder their large-scale implementation. Here, three-dimensional hierarchical porous (3DHP) Fe 3 O 4 /Fe-N-C composites were prepared via the hard template method. Notably, Fe 3 O 4 /Fe-N-C-0.04-600 demonstrated uniformly dispersed Fe 3 O 4 nanoparticles and abundant Fe-N x and pyridinic nitrogen, showing excellent catalytic performance for oxygen reduction reaction (ORR) with a half-wave potential (E 1/2) of 0.74 V (vs. RHE), surpassing Pt/C (0.66 V vs. RHE). Moreover, Fe 3 O 4 /Fe-N-C-0.04-600 demonstrated favorable biocompatibility as an anode material, enhancing anode biomass and extracellular electron transfer efficiency. Sequencing results confirmed its promotion of electrophilic microorganisms in the anode biofilm. MFCs employing Fe 3 O 4 /Fe-N-C-0.04-600 as both anode and cathode materials achieved a maximum power density of 831.8 ± 27.7 mW m−2, enduring operation for 38 days. This study presents a novel approach for rational MFC design, emphasizing bifunctional materials capable of serving as anode materials for microorganism growth and as cathode catalysts for ORR catalysis. [ABSTRACT FROM AUTHOR]

The present study reports the successful preparation of pure magnetite Fe 3 O 4 (F), bismuth doped Fe 3 O 4 (FB), reduced graphene oxide doped Fe 3 O 4 (FR), and bismuth-rGO co doped Fe 3 O 4 (FBR) using the simple co-precipitation process. The produced samples were subjected to morphological, optical, FTIR, and structural analyses. XPS- Photo electron spectroscopy indicates the presence of relevant elements and oxidation states. BET surface analysis shows the presence of enhanced surface area in conjointly doped Fe 3 O 4 (FBR) and rGO doped Fe 3 O 4 (FR). The photocatalytic activity of the materials (F, FB, FR, and FBR) against several organic dyes [MB, Rho-b, and Congo red (CR)] was investigated. Using the disc diffusion method, the antibacterial activity of the samples was investigated against a variety of gramme positive and gramme negative bacteria. The findings indicate that the co-doped magnetite nano composite exhibits strong antimicrobial activity. The synthesised materials were also used as electrode materials for supercapacitors. The electrochemical performance of the FBR-based supercapacitor was reliable, and it exhibited a high specific capacitance of 732.51 Fg-1 at a current density of 1 Ag-1. From the CV analysis, the measured capacitance was 440.67 Fg-1 for a three-electrode configuration. The symmetric device has been constructed using bismuth and rGO co doped (FBR) nano composite and it exhibited a specific capacitance of 173 Fg-1, specific energy of 24 W h Kg1, and specific power of 1999 W Kg-1 at a current density of 1 Ag-1 with notable cyclic stability of about 89 % and had average capacity retention and excellent coulombic efficiency which is about 95 % up to 8000 cycles which is retained even after 18,000 cycles. [ABSTRACT FROM AUTHOR]

Regenerable nanozymes with high catalytic specificity and sustainability may serve as substitutes for naturally occurring enzymes, but their application is hindered by inadequate and nonselective catalytic activity. In this study, we constructed a photo-responsive molecularly imprinted layer on the Fe 3 O 4 nanozyme surface (P-MIPs) using an ATRP method and obtained high-specificity reversible colorimetric sensing of tetracycline (TC). Due to the photo-responsive properties of P-MIPs, the imprinted nanozyme undergoes reversible release and uptake of TC under alternating irradiation at 365/440 nm based on the photo-regulated conformational transformation of the 4-[(4-methacryloyloxy)phenylazo] benzenesulfonic acid (MAPASA) at the polymer receptor sites, which may be confirmed by calculating the electron densities of the trans-/cis -MAPASA forms. Simultaneously, these processes can be visualized through the change in the color of the substrates. Highly specific P-MIPs-based nanozyme also exhibit adequate stability and sustainable catalytic activity after multiple cycles. This method can be used to achieve nanozymes with high selectivity for the enrichment, separation, and detection of hazardous substances and contribute to material sustainability. [Display omitted] • Developing a high catalytic specificity and sustainable nanozyme sensing platform. • Achieving sustainable reversible colorimetric sensing for tetracycline. • Showing superior the photo-driven reversible extraction functions to hazardous substances. [ABSTRACT FROM AUTHOR]

Exosomes, the bioactive particles secreted by various cells, are essential in mediating cellular communication. However, their small size and the interference from non-exosome proteins present significant hurdles for their rapid and non-destructive capture and release. To overcome these obstacles, a promising strategy to efficiently and selectively isolate exosomes from mesenchymal stem cells (MSCs) is developed by using CD63 aptamer-conjugated magnetic nanoparticles (Fe 3 O 4 -Aptamer). The Fe 3 O 4 nanoparticles are first modified by RAFT polymerization of N-(methacryloyloxy) succinimide and oligoethylene glycol methacrylate, and subsequently, CD63 aptamers are grafted onto the surface of nanoparticles to produce Fe 3 O 4 -Aptamer. These aptamer units act as a "lock and key" recognition with the CD63 proteins on exosomes, enabling specific binding to exosomes. The Fe 3 O 4 -Aptamer can efficiently capture exosomes in a conditioned medium, and be easily collected by an external magnetic field, facilitating the facile collection and multiple-cycle reuse of Fe 3 O 4 -Aptamer. By introducing the complementary sequence of the CD63 aptamer, the captured exosomes can be rapidly released from Fe 3 O 4 -Aptamer because of the stronger binding affinity between the complementary sequence and the aptamers. When utilized for exosome isolation, the exosome-capture and release efficiency of Fe 3 O 4 -Aptamer can achieve up to ca. 82.9% and 96.1%, respectively. Thus, Fe 3 O 4 -Aptamer offers a promising and facile strategy for the highly efficient isolation of exosomes., (© 2025 Wiley‐VCH GmbH.)