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The possible adverse effects of engineered iron oxide nanoparticles, especially magnetite (Fe3O4 NP), on human health and the environment, have raised concerns about their transport and behavior in soil and water systems. Accumulating these NPs in the environment can substantially affect soil and water quality and the well-being of aquatic and terrestrial organisms. Therefore, it is essential to examine the factors that affect Fe3O4 NP transportation and behavior in soil and water systems to determine their possible environmental fate. In this work, experiments were conducted in aqueous and porous media using an environmentally relevant range of pH (5, 7, 9), ionic strength (IS) (10, 50, 100 mM), and humic acid (HA) (0.1, 1, 10 mg L−1) concentrations. Fe3O4 NPs exhibited severe colloidal instability at pH 7 (⁓ = pHPZC) and showed an improvement in apparent colloidal stability at pH 5 and 9 in aquatic and terrestrial environments. HA in the background solutions promoted the overall transport of Fe3O4 NPs by enhancing the colloidal stability. The increased ionic strength in aqueous media hindered the transport by electron double-layer compression and electrostatic repulsion; however, in porous media, the transport was hindered by ionic compression. Furthermore, the transport behavior of Fe3O4 NPs was investigated in different natural waters such as rivers, lakes, taps, and groundwater. The interaction energy pattern in aquatic systems was estimated using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. This study showed the effects of various physical–chemical conditions on Fe3O4 NP transport in aqueous and porous (sand) media. [ABSTRACT FROM AUTHOR]

Dyes pollution is a serious environmental problem and heterogeneous catalysis has been proposed as a remediation method. In this study, a set of catalysts of synthetic mordenite with iron oxides was synthesized by a simple chemical co-precipitation method assisted by subsequent thermal treatment with an oxidation process. Physicochemical characterization of prepared materials was performed by a variety of techniques, including XRD, SEM, EDS, SBET, UV–Vis DR, and XPS. Photocatalytic methylene blue (MB) degradation by the synthesized catalyst was evaluated with visible light excitation. From the studied set of catalysts, the sample prepared with a thermal treatment at 100 °C in air atmosphere for 3 h was capable of degrading ~ 90% of MB after 120 min with visible light of λ = 420 nm exposition and a small portion of H2O2 added. The catalyst used three processes to degrade MB: (1) adsorption of organic residues in the mordenite matrix support for electrostatic interactions, (2) photocatalysis heterogeneous reaction with visible light and (3) Fenton reaction catalyst with a small portion to H2O2 by Fe3O4–Fe2O3 presence. The catalytic efficiency to dye degradation was improved by a simple and economical thermal treatment without changing reaction conditions like pH, temperature, dose, or other. Studied mordenite iron oxide catalysts can be retrieved and reused at least five times without noticeable degradation, taking advantage of their magnetic properties. These catalysts could be proposed an economical, simple, and non-toxic alternative for eliminating organic dye pollution using visible light or solar irradiation in wastewater remediation related to textile, food, and pharmaceutical industries.Highlights: The Fe3O4–Fe2O3 supported on mordenite catalyst was synthesized for the first time by a simple and cost-effective chemical method. Elimination of methylene blue using the catalyst synthesized was accomplished with visible light excitation. Reuse of the catalyst for the photodegradation process of dyes from aqueous solution was achieved by magnetic retrieval. It was possible to improve the photocatalytic efficiency by facile and economical thermal treatments without changing the pH, temperature, dose, or other conditions. [ABSTRACT FROM AUTHOR]

The synthesis of oxides using plant extracts as precursors has attracted attention as it is an economical, efficient, and ecological route. Euterpe oleracea Mart, available in the Legal Amazon, has great potential due to its composition, rich secondary metabolites. Therefore, this work aimed to investigate the potential of aqueous açaí leaf extract as precursors in synthesizing FexOy-type oxides. The synthesis was developed in two stages to obtain the hematite phases (step 1) and the magnetite phase (step 2). The effect of pH on phase formation and structure was evaluated in step 1. Then, the material was obtained in step 2 by precipitation with pH adjustment. The powders were characterized by thermal analysis, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. The results showed that pH played a significant role in the thermal behavior, crystallite sizes, and structural parameters of hematite, with neutral or acidic pH being more attractive for obtaining crystallites between 21 and 24 nm. Magnetite with 21.51 nm crystallites was precipitated, indicating possible capping of the Fe3O4 particles and preserving their magnetic characteristics.

Background: Magnetic nanoparticles attract increasing interest due to their use in cancer therapy and as drug carriers for several other diseases. The present study investigates the physiochemical properties of quercetin-conjugated superparamagnetic Fe3O4 nanoparticles and their effects on breast cancer cell line MCF-7. Methods: A simple precipitation method was used to prepare the Poly Ethylene Imine (PEI)-coated Fe3O4 nanoparticles; they were then conjugated with flavonoid-compound quercetin on the surface via carboxylic/amine group using nanoprecipitation method. Then, the physical and chemical parameters were calculated using Zeta-sizer, scanning electron microscopy (SEM), and extract release patterns at 37 and 42 0C. Finally, the toxicity level of this quercetin- conjugated nanosystem on the MCF-7 cells was investigated by MTT assay. Results: The results showed that the prepared nanosystem attained about 74% of quercetin inclusion, 91.2 nm size, 65.1 mV zeta potential, spherical morphology and a controlled release. Compared to Fe3O4 nanoparticles and pure quercetin, MTT and microscopy analysis revealed that quercetin-conjugated Fe3O4 nanoparticles induced considerable cytotoxicity, and morphology changes against MCF7 cells. Conclusion: Quercetin-conjugated Fe3O4 nanoparticles have appropriate physiochemical properties; they can be a suitable carrier for drug delivery and a promising therapy for candidates. Corresponding Author:Bibi Fatemeh Haghiralsadat View Orcid in Profile You can search for this author in PubMed Google Scholar Profile

Nano-sized Fe3O4 particles were continuously synthesized in the rotating packed bed with blade packings where the rotational speed was set at 1800 rpm, the liquid flow rate of aqueous FeCl2/FeCl3 was kept at 0.5 L/min, and the liquid flow rate of aqueous NaOH was maintained at 0.5 L/min with the chemical co-precipitation route that the synthesis temperature was fixed at 25 °C, the FeCl2 concentration was fixed at 0.15 mol/L, the FeCl3 concentration was fixed at 0.3 mol/L, and the NaOH concentration was fixed at 1.2 mol/L. The average crystallite size and mean particle size of the as-synthesized nano-sized Fe3O4 particles were 12.7 nm and 10.9 nm, respectively. The rate of continuous synthesis of nano-sized Fe3O4 particles was 23.6 kg/day. The as-synthesized nano-sized Fe3O4 particles exhibited a superparamagnetic characteristic at 25 °C. Furthermore, the saturation magnetization of the as-synthesized nano-sized Fe3O4 particles was 66.4 emu/g. The as-synthesized nano-sized Fe3O4 particles had the Type-IV isotherm for N2 adsorption-desorption with a BET specific surface area of 109.4 m2/g. The maximum Orange G adsorption capacity of the as-synthesized nano-sized Fe3O4 particles at 25 °C and pH 3 was 55.0 mg/g. This maximum Orange G adsorption capacity was much higher than that (5.7 mg/g) of the commercial nano-sized Fe3O4 particles that were purchased from Sigma-Aldrich (SA-Fe3O4) because the as-synthesized nano-sized Fe3O4 particles had a smaller mean particle size than SA-Fe3O4. Accordingly, the as-synthesized nano-sized Fe3O4 particles are a promising magnetic adsorbent in the removal of Orange G from water.

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. 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.

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.

The focus of the present study is on the fabrication of effective and eco-friendly hybrid electrospun materials based on poly(L-lactide-co-D,L-lactide) (PLDLLA), Fe3O4 and ZnO with an appropriate design for antioxidant and photocatalytic performance. The design of the fibrous materials was purposely tailored in one step by electrospinning and simultaneous electrospinning/electrospraying. Electrospinning of PLDLLA and its mixture with Fe3O4 resulted in the fabrication of materials with design type “in”. Furthermore, the surface of the electrospun PLDLLA and Fe3O4-in-PLDLLA was decorated with ZnO particles by simultaneous electrospraying, thus materials with design type “on” were obtained. In this case, quaternized N,N,N-trimethyl chitosan iodide (QCOS) was used as a sticking agent of ZnO particles onto the fiber’s surface. Different structures and morphologies of the electrospun materials were observed by SEM equipped with EDX and TEM. TGA and XRD analyses show that the presence of inorganic particles had an impact on the thermal properties and crystallinity of the electrospun materials. Furthermore, the material type “on” showed improved wettability with a water contact angle less than 90° compared to the material type “in” with an angle larger than 90°. In particular, the presence of Fe3O4 imparts complementary magnetic properties, while ZnO considerably increased the antioxidant activity of the fibrous materials. Materials with design type “on” displayed over 70% radical scavenging capacity in contrast to the material type “in” with less than 20% capacity within 30 min of contact. Moreover, the purposely tailored design type “on” materials provided excellent photocatalytic degradation of model organic pollutant methylene blue dye under UV light irradiation even after 5-fold use, and at the end of the fifth cycle these materials degraded more than 90% of the dye. These results reveal not only a strategy for the fabrication of electrospun hybrid bio-based materials with targeted design but also provide a promising, simple and effective way for mitigating water pollution.

In this study, a new type of highly efficient and recyclable magnetic-fluorine-containing polyether composite demulsifier (Fe3O4@G-F) was synthesized by the solvothermal method to solve the demulsification problem of oil–water emulsion. Fe3O4@G-F was successfully prepared by grafting fluorinated polyether onto Fe3O4 and graphene-oxide composites. Fe3O4@G-F was characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Taking the self-made crude-oil emulsion as the experimental object, the demulsification mechanism of the demulsifier and the influence of external factors, such as the temperature and pH value, on the demulsification performance of the demulsifier are discussed. The results show that the demulsification efficiency of the Fe3O4@G-F emulsion can reach 91.38% within 30 min at a demulsifier dosage of 750 mg/L, pH of 6, and a demulsification temperature of 60 °C. In neutral and acidic environments, the demulsification rate of the demulsifier is more than 90%. In addition, Fe3O4@G-F has been proven to have good magnetic effects. Under the action of an external magnetic field, Fe3O4@G-F can be recycled and reused in a two-phase system four times, and the demulsification efficiency is higher than 70%. This magnetic nanoparticle demulsifier has broad application prospects for various industrial and environmental processes in an energy-saving manner.

Purposes Combining the high selectivity of natural enzymes with the high stability of nanoenzymes in a one-pot reaction has emerged as an ideal solution to improving the diversity/complexity of biocatalytic cascades and the stability of multi-enzyme systems. Methods In this paper, we designed and synthesized an ionic magnetic Fe3O4@EB-COFs material to prepare glucose oxidase (GOx)-magnetic covalent organic framework material(GOx/Fe3O4@EB-COFs) through electrostatic interaction induction. Findings Fe3O4@EB-COFs played the role of nanoparticle enzyme and carrier material, and the obtained composite could be used for glucose concentration for colorimetric determination. Under acidic conditions, GOx/Fe3O4@EB-COFs exhibited a good cascade of catalytic glucose oxidation and 2,2′-biazo-bis-3-ethylbenzothiazoline-6-sulfonic acid oxidation. The kinetic study showed that the reaction followed the Lineweaver-Burk equation, indicating that the cascade reaction of the constructed nanoenzyme with natural enzyme still exhibited biocatalytic characteristics. GOx/Fe3O4@EB-COFs exhibited good recoverability with the addition of magnetic Fe3O4. Conclusions Therefore, the construction of a multi-enzyme catalytic system of nanoenzymes and natural enzymes is important for the realization of biomimetic catalysis.

Background: Using magnetic nanoparticles has significant attention in various domains, including magnetic storage, medical therapies, and magnetic detection. Curcumin (diferuloylmethane), a polyphenol, is a low molecular weight active ingredient of the perennial herb Curcuma longa (commonly known as turmeric). Methods: The APTES-coated magnetite nanopowders were prepared as carriers for the anticancer drug “Curcumin” through the modified controlled chemical co-precipitation method. The concentration of Curcumin release in the HA-magnetite nanoparticles in 20 ml phosphate buffer (pH 7.4) within the PBS was determined at unique time intervals using UV-Vis Spectrophotometer as finished within the drug loading measurement. The in vitro cytotoxicity of the nanoparticles became assessed through MTT cellular viability assay after treating the MCF-7 breast adenocarcinoma cells with Curcumin-loaded APTES-covered magnetic NPs in addition to unloaded magnetic NPs in line with the manufacturer’s commands. Results: The APTES and HA-coated and uncoated Fe3O4 nanoparticles were characterized by XRD, FE-SEM, FT-IR, Raman, and VSM techniques. The size of the Fe3O4 nanoparticles and their distribution were determined by Hydrodynamic length distribution. TEM results revealed that the average particle size is 15 nm. The VSM measurements showed that magnetic particles were superparamagnetic characteristics. Rapid Curcumin drug loading in 2 hrs and the controlled drug release in 1 hr ~15% and 48 hrs ~80% drug release was observed, applying to in-vitro applications. The obtained findings indicated that the APTES- Fe3O4/HA nanoparticles are promising for targeted Curcumin drug delivery applications. Conclusion: Curcumin-loaded MNPs were more potent than free Curcumin for inhibiting MCF-7 cell proliferation due to enhanced uptake in breast cancer cells. Due to high inherent magnetic properties, we may use the nanomedicine platforms for theranostic application after ensuring the MRI imaging abilities.

Extensive studies were devoted to iron oxide nanoparticles (IONPs), in recent years. Iron oxides are chemical compounds that have various polymorphic forms, including maghemite (γ-Fe2O3), magnetite (Fe3O4), and Hematite (α-Fe2O3). Among them, the most important studied is magnetite (Fe3O4) due to its low cost and low toxicity, besides its unique magnetic and physicochemical characteristics which qualified it for use in various applications such as biomedical and technological applications. Magnetic particles should be small and have a narrow size distribution for these applications. The smaller the size of the iron oxide particles, the greater their reactivity and biodegradability. In this review, we display summary information of magnetite (Fe3O4) nanoparticles in terms of structure, characteristics, and preparation methods. Because the prepared strategy has been proven to be critical for preferable control of the particle size and shape, in addition, to producing monodispersed magnetite (Fe3O4) nanoparticles with a direct effect on their characteristics and applications, special attention will be placed on chemical preparation techniques including Hydrothermal synthesis, Co-precipitation technique, Sol-Gel process, and thermal decomposition method. This review offers specific information for selecting appropriate synthetic methods for obtaining appropriate sizes, shapes, and magnetic properties of magnetite (Fe3O4) nanoparticles (NPs) for target applications.

Magnetic nanoparticles, such as magnetite (Fe3O4), exhibit superparamagnetic properties below 15 nm at room temperature. They are being explored for medical applications, and the coprecipitation technique is preferred for cost-effective production. This study investigates the impact of synthesis temperature on the nanoparticles' physicochemical characteristics. Two types of magnetic analysis were conducted. Samples T 40, T 50, and T 60 displayed superparamagnetic behavior, as evidenced by the magnetization curves. The experiments verified the development of magnetic nanoparticles with an average diameter of approximately dozens of nanometers, as determined by various measurement methods such as XDR, Raman, and TEM. Raman spectroscopy showed the characteristic bands of the magnetite phase at 319, 364, 499, and 680 cm−1. This was confirmed in the second analysis with the ZFC-FC curves, which showed that the samples' blocking temperatures were below ambient temperature. ZFC-FC curves revealed a similar magnetization of about 30 emu/g when applying a magnetic field of 5 kOe.

Organic pollutants in wastewater pose serious threats to human health and the environment. Nevertheless, potent strategies are being devised to tackle this critical issue. Specifically, advanced oxidation processes driven by solar energy and photocatalysts show promise for the degradation of organic pollutants. In particular, porous nanomaterials are effective as photocatalysts because of their high surface area, light‐harvesting properties, and ability to generate reactive oxygen species. To further expedite the development of feasible and sustainable organic‐pollutant‐degrading schemes, this article reports a strategy rooted in selective core etching for fabricating a core‐satellite‐type porous Fe3O4–Au nanocomposite. The Fe3O4 core behaves as a semiconductor to generate electron–hole pairs, whereas the Au satellite units serve as hot‐electron donors under visible‐light irradiation. The nanocomposite exhibits exceptional photocatalytic activity, degrading methylene blue molecules by 97% in just 1 h under visible light, and maintains its photocatalytic performance even after five rounds of recycling. Moreover, the nanocomposite achieves 90% tetracycline decomposition within 2 h. In addition to exhibiting noteworthy photocatalytic activity, the nanocomposite is magnetically separable, facilitating its recovery and reuse and exhibiting remarkable stability and cost‐effectiveness. These attributes underscore the practical viability of the core‐satellite‐type Fe3O4–Au nanocomposite in wastewater treatment.

This research work describes the synthesis and characterization of Cellulose@SiPr@Catechin@Fe3O4 nanocomposite, a novel and effective nanocatalyst in the synthesis of 1,5-benzodiazepine derivatives by reaction of 1,2-phenylenediamine, Meldrum's acid and azo aldehydes. 1H NMR, 13C NMR, and FTIR spectral data and mass analyses characterized all products. The nanocatalyst was characterized by fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), X-ray powder diffraction (XRD), X-ray spectroscopy (EDX), vibrating sample magnetometry (VSM), and thermogravimetric analysis (TGA).

Modification of silica purified from the Merapi volcanic ash with magnetic material of Fe3O4 and attachment of cetyl triamine bromide (CTA-Br) on the magnetic cored has been performed to provide recoverable and positive surfaced of natural adsorbent. The magnetic cored was prepared via co-precipitation and CTA-Br attachment was conducted by a facile strategy. Then, the modified adsorbents were characterized by SEM, TEM, XRD, and FTIR instruments and examined for removing anionic Cr(VI) from the water media. The characterization data confirmed that crystals of Fe3O4 coated by SiO2 that has been bound with CTA-Br have been successfully formed. Additionally, increasing CTA-Br loaded gives thicker lamination on Fe3O4@SiO2/CTA-Br, but the CTA-Br loaded with higher than 0.25 mmol, leads to the coating peeled out. It is also demonstrated that Fe3O4@SiO2/CTA-Br prepared with CTA-Br 0.25 mmol is ideal for Cr(VI) anionic removal, regarding to the highest adsorption and very good separation or recovery process. Moreover, the optimal dose of Fe3O4@SiO2/CTA-Br in the Cr(VI) removal was observed at 0.25 g/20 mL under condition of pH 3 for 60 min. The adsorption of Cr(VI) well fits the Langmuir isotherm model with an adsorption capacity of 3.38 mg g-1 and is in a good agreement with pseudo-second order giving kinetic constant at 0.005 g mg−1 min-1. Thus, it is clear that the natural adsorbent material with recoverable properties for more efficient and wider application of removal Cr(VI) contaminant was expected from this study.

In present work, one-pot preparation of Fe3O4/NiFe2O4 nanocomposite catalyst was investigated using iron rust waste as precursor. The synthesis was performed by coprecipitation followed by hydrothermal method using iron rust waste as iron precursor, and NiCl3 as nickel precursor. The catalytic properties of material were tested on methyl violet catalytic oxidation. The results from x-ray diffraction, x-ray photoelectron spectroscopy, and scanning electron spectroscopy confirmed the formation of Fe3O4/NiFe2O4 without any other impurities. Particle size analysis using and transmission electron microscopy revealed that the use of iron rust waste gave the smaller particle's size of the nanocomposite compared to the use of Fe(III) precursor. The sample expressed the smaller saturation magnetization, but higher specific surface area and porosity are supporting feature to increase the catalytic activity in methyl violet oxidation. The optimum degradation efficiency of >95% is expressed for degradation of methyl violet (MV) with concentration range of 10–50 ppm. Reusability of the nanocomposite was demonstrated as there is insignificant change of the activity until 5th usage. The research revealed the potency of iron rust waste to be source of functional material and can be notified as a potential strategy for environmental management and application.

An operationally convenient and efficient one-pot reductive amination of diversely substituted aldehydes catalyzed by Fe3O4@TiO2 nanoparticles and NaBH4 as a reductant in ethanol at ambient condition is reported in this work. The structural features of Fe3O4@TiO2 nanoparticles are explored by various tools like FT-IR, XRD, TEM, FE-SEM and EDX techniques. The heterogeneous nature, good catalytic potential and reusability are some of the important attributes of the catalyst. The beneficial features of this procedure are one-pot reaction, short reaction time, low catalyst requirement, applicability to wide range of substrates with good yields, milder and simple reaction condition. The structures of synthesized amine derivatives were established by 1H-NMR, 13C-NMR and HR-MS spectral analysis. [ABSTRACT FROM AUTHOR]

Prepared by the method of grafting polymerization on the surface of a new type of magnetic flocculant Fe3 O4-g-PAM, the flocculant to non-toxic environmental ferroferric oxide and industry commonly used polyacrylamide together, overcome the shortcomings of the two kinds of materials respectively ・ Results show that the preparation of magnetic flocculants its good flocculation performance・ By flocculating 1 g/L Kaolin suspension, the flocculation effect is the best when the dosage of PAC is L 0 mL/L, the flocculation time is 20 min, the dosage of Fe3O4-g・PAM is L 0 g/L, and the turbidity can be decreased from 1 245. 37 NTU to 0. 69 NTU. [ABSTRACT FROM AUTHOR]

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The research of nanomaterials for bio-imaging and theranostic are very active nowadays with unprecedented advantages in nanomedicine. Homologous targeting and bio-imaging greatly improve the ability of targeted drug delivery and enhance active targeting and treatment ability of nanomedicine for the tumor. In this work, lycorine hydrochloride (LH) and magnetic iron oxide nanoparticles coated with a colorectal cancer (CRC) cell membrane (LH-Fe3O4@M) were prepared, for homologous targeting, magnetic resonance imaging (MRI), and chemotherapy. Results showed that the LH-Fe3O4@M and Fe3O4@M intensity at HT29 tumor was significantly higher than that Fe3O4@PEG, proving the superior selectivity of cancer cell membrane-camouflaged nanomedicine for homologous tumors and the MRI effect of darkening contrast enhancement were remarkable at HT29 tumor. The LH-Fe3O4@M exhibited excellent chemotherapy effect in CRC models as well as LH alone and achieved a high tumor ablation rate but no damage to normal tissues and cells. Therefore, our biomimetic system achieved a homologous targeting, bio-imaging, and efficient therapeutic effect of CRC. [ABSTRACT FROM AUTHOR]

In this paper, two types of microspheres encapsulating magnetic carboxyl-modified Fe3O4 have been synthesized to compare their adsorption to Congo Red, one has been prepared by taking 3-aminopropyltriethoxysilane (APTES) as the functional monomer; the other has utilized chitosan and gelatin as the wall materials. The former is named as ASM and the latter is called as CGM. SEM, FTIR, XRD and TGA have been used to characterize the morphology and structure of microspheres. The adsorption experiments have shown that they both could absorb the dye rapidly and continuously and adsorption kinetics conform to pseudo-second-order model. The adsorption test data of ASMs have been fitted better with the Freundlich isotherms. The CGMs follow Langmuir isotherms. The maximum adsorption capacity of the dye onto the former at room temperature is 585 mg/g and the latter is 364 mg/g, indicating highly efficient adsorption capacity. The high reusability means that the products have promising potentials in advanced treatment of industrial wastewater. [ABSTRACT FROM AUTHOR]

Dendrite growth has been the main trouble preventing the practical application of Li metal anodes. Herein, we present how an Fe3O4-PVDF composite network prepared by using electrospinning has been designed to protect lithium metal anodes effectively. In the symmetrical cells test, the cell with the Fe3O4-PVDF composite network maintains good cycle performance after 600 h (500 cycles) at a current density of 1 mA cm−2 and a plating/stripping capacity of 1 mAh cm−2. The bulky Li dendrite is suppressed and a uniform Li deposition remains after long cycling. The characteristics of this engineered separator are further demonstrated in Li-S full cells with a good cycle performance (capacity of 419 mAh g−1 after 300 cycles at 0.5 C). This work provides a new idea for the protection of lithium metal anodes. [ABSTRACT FROM AUTHOR]

A nano-Fe3O4/few-layered graphene (FLG) composite is prepared for ultrasensitive detection of dopamine (DA) in the presence of interfering uric acid (UA) and ascorbic acid (AA) molecules. The sensor material is prepared by a completely solid-state process. The sensor works on the synergy between the peroxidase-like behavior of nano-Fe3O4 and the electrocatalytic activity of FLG to detect DA, UA, and AA with excellent sensitivity and selectivity using differential pulse voltammetry. DA is detected in two linear ranges, 3.33–19 and 23–62.3 nM, with the detection limit and quantification limit as 0.413 and 1.239 nM, respectively. The practical viability of the nano-Fe3O4/FLG-based sensor is confirmed by performing analysis using human serum and synthetic commercial drug samples. The calculated limit of detection and linear dynamic range values pertaining to the detection of DA, UA, and AA molecules through electro-oxidation in the presence of each other are also found to be excellent. [ABSTRACT FROM AUTHOR]

Heterogeneous bi‐magnetic nanostructured systems have had a sustained interest during the last decades owing to their unique magnetic properties and the wide range of derived potential applications. However, elucidating the details of their magnetic properties can be rather complex. Here, a comprehensive study of Fe3O4/Mn3O4 core/shell nanoparticles using polarized neutron powder diffraction, which allows disentangling the magnetic contributions of each of the components, is presented. The results show that while at low fields the Fe3O4 and Mn3O4 magnetic moments averaged over the unit cell are antiferromagnetically coupled, at high fields, they orient parallel to each other. This magnetic reorientation of the Mn3O4 shell moments is associated with a gradual evolution with the applied field of the local magnetic susceptibility from anisotropic to isotropic. Additionally, the magnetic coherence length of the Fe3O4 cores shows some unusual field dependence due to the competition between the antiferromagnetic interface interaction and the Zeeman energies. The results demonstrate the great potential of the quantitative analysis of polarized neutron powder diffraction for the study of complex multiphase magnetic materials. [ABSTRACT FROM AUTHOR]

In this paper, Magnetite/Saponite (Fe 3 O 4 /Sap) composites were prepared by hydrothermal synthesis and co-precipitation. The prepared Fe 3 O 4 /sap composites had high purity and good crystallinity, and nano-Fe 3 O 4 was uniformly dispersed on the surface of saponite. Moreover, the removal efficiency of Fe 3 O 4 /Sap composites for Cr (VI) in water was evaluated. This study revealed the existence of abundant oxygen vacancies and hydroxyl groups on the surface of Saponite. During the synthesis of Fe 3 O 4 on the surface of Sap, the multi-directional crystallization can be controlled to increase the reaction activity of the system. Besides, the prepared Fe 3 O 4 /Sap composites provided more reactive edges compared to Fe 3 O 4 in the process of removing Cr (VI). The removal amount of Cr (VI) was found to be 17.95 ​mg/g. The successful preparation of the Fe 3 O 4 /Sap composites and the revelation of the Cr (VI) adsorption mechanism are of great significance for the efficient and green removal of heavy metal pollutants in sewage. [ABSTRACT FROM AUTHOR]

In order to separate the colloidal in high-turbidity water, a kind of magnetic composite (Fe3O4/HBPN) was prepared via the functional assembly of Fe3O4 and an amino-terminal hyperbranched polymer (HBPN). The physical and chemical characteristics of Fe3O4@HBPN were investigated by different means. The Fourier Transform infrared spectroscopy (FTIR) spectra showed that the characteristic absorption peaks positioned at 1110 cm−1, 1468 cm−1, 1570 cm−1 and 1641 cm−1 were ascribed to C–N, H–N–C, N–H and C=O bonds, respectively. The shape and size of Fe3O4/HBPN showed a different and uneven distribution; the particles clumped together and were coated with an oil-like film. Energy-dispersive spectroscopy (EDS) displayed that the main elements of Fe3O4/HBPN were C, N, O, and Fe. The superparamagnetic properties and good magnetic response were revealed by vibrating sample magnetometer (VSM) analysis. The characteristic diffraction peaks of Fe3O4/HBPN were observed at 2θ = 30.01 (220), 35.70 (311), 43.01 (400), 56.82 (511), and 62.32 (440), which indicated that the intrinsic phase of magnetite remained. The zeta potential measurement indicated that the surface charge of Fe3O4/HBPN was positive in the pH range 4–10. The mass loss of Fe3O4/HBPN in thermogravimetric analysis (TGA) proved thermal decomposition. The –C–NH2 or –C–NH perssad of HBPN were linked and loaded with Fe3O4 particles by the N–O bonds. When the Fe3O4/HBPN dosage was 2.5 mg/L, pH = 4–5, the kaolin concentration of 1.0 g/L and the magnetic field of 3800 G were the preferred reaction conditions. In addition, a removal efficiency of at least 86% was reached for the actual water treatment. Fe3O4/HBPN was recycled after the first application and reused five times. The recycling efficiency and removal efficiency both showed no significant difference five times (p > 0.05), and the values were between 84.8% and 86.9%. [ABSTRACT FROM AUTHOR]

Functional Fe3O4 nanoparticle (Fe3O4 NP) is one of the most attractive candidates in the demulsification field because of its outstanding recycling ability, low cytotoxicity, and good biocompatibility. However, the lack of research on their interfacial properties greatly inhibits further development in the industrial demulsification process. The main aim of this work is to explore interfacial properties of functional Fe3O4 NPs from their intrinsic natures, namely morphologies and structures. Three Fe3O4 NPs with different morphologies, including triangle-shaped Fe3O4 NPs (TF NPs), octahedron-shaped Fe3O4 NPs (OF NPs) and truncated octahedron-shaped Fe3O4 NPs (TOF NPs), were prepared by using the solvothermal reaction. Their demulsification capacities of water-in-cyclohexane (W/C) emulsion were evaluated and the TOF NPs had best performance. The demulsification process including diffusion, adsorption and phase separation stages of these Fe3O4 NPs were investigated in detail by interfacial experiments and mathematical models for explain the demulsification result. The diffusion coefficient was calculated at both the early and late stages of the demulsification process, along with their adsorption energy and the elastic modulus of oil-water interfaces. TOF NPs had the largest diffusion coefficient of 1.777 × 10−6 and 2.443 × 10−6 m2/s at the early and late stages, respectively. The W/C interface adsorption energy of TOF NPs were much lower than that of the others and the elastic modulus of W/C interface reduced by TOF NPs was also more effective than that by the others. [ABSTRACT FROM AUTHOR]

Chemical agents pose a significant threat to social security, highlighting the crucial role of representative chemical agents adsorption in ensuring the safety our environment. This study explored the application of Magnetic Graphene Oxide Nanoplatelet Composites (MGONCs) in adsorbing the representative chemical agents such as Lewisite (L), O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), Sarin (GB), and Soman (GD). MGONCs were synthesized through a physical blending method, with the combination of graphene oxide (GO) and Fe3O4 nanoparticles at a mass ratio of 1:1. Optimization of the adsorption process involved investigating the effects of contact time, temperature, and adsorbent dosage. Remarkably, the adsorption rate of L and VX exceeded 99% when the dosage of MGONCs was 2.5 mg, with a contact time of 30 s at room temperature. Furthermore, GB and GD achieved maximum adsorption rates after a contact time of 20 min, with the dosages of MGONCs at 10 mg and 20 mg, respectively. Characterization of the magnetic composite was accomplished through XRD, TEM, VSM, FTIR, TGA, and BET analyses. Kinetical analysis revealed that the adsorption mechanism of GB and GD on MGONCs followed pseudo-second-order (PSO) kinetics, exhibiting a high regression coefficient. The calculated q e values were 0.103125 mg/g and 0.081349 mg/g, respectively. This research demonstrated the feasibility of utilizing MGONCs as highly efficient adsorbents for representative chemical agents, particularly in on-site sampling scenarios. [ABSTRACT FROM AUTHOR]

Fe3O4 and Cu2O were successively immobilized on alkali-treated straw, and the magnetically separable straw@Fe3O4/Cu2O composite was obtained. The straw@Fe3O4/Cu2O was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometry, respectively. Photocatalytic performance of the straw@Fe3O4/Cu2O was evaluated by measuring the degradation of methyl orange (MO) under irradiation of visible light. The introduction of Fe3O4 not only endowed the straw@Fe3O4/Cu2O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs. The active species capture experiment showed that holes (h+), hydroxyl (·OH) and superoxide (·O2−) radicals all took part in the MO degradation. In addition, the photocatalytic mechanism of straw@Fe3O4/Cu2O was proposed based on the experimental results. After five cycles for the photodegradation of MO, the straw@Fe3O4/Cu2O still displayed good photocatalytic activity, suggesting that the as-prepared composite had great potential for practical use in wastewater treatment. [ABSTRACT FROM AUTHOR]

This article explores the thermal degradation kinetics of modified Fe3O4 with poly(vinyl chloride) (PVC) using click chemistry. The authors analyze the thermal properties of the modified Fe3O4 and its precursors, as well as the thermal characteristics of the final product through thermogravimetric analysis (TGA). They determine the thermal degradation kinetic parameters using the Flynn-Wall-Ozawa method (FWO) and Kissinger-Akahira-Sinuse method (KAS). The results indicate that the modified polymer exhibits good thermal stability. The study also examines the saturation magnetization of the modified Fe3O4. Overall, this research provides valuable insights into the thermal degradation behavior and thermal stability properties of modified magnetic nanoparticles, which can have potential industrial applications. [Extracted from the article]

A new nanocomposite system based on Fe3O4 nanoparticles confined in three-dimensional (3D) dual-mode cubic porous carbon is developed using the nanocasting and wet-impregnation methods to assess its performance as an anode for lithium-ion batteries. Several Fe3O4 precursor concentrations are chosen to optimize and determine the best-performing nanocomposite composition. The cubic mesoporous carbon CMK-9 offers a better ability for the Fe3O4 nanoparticles to be accommodated inside the mesopores, efficiently buffering the variation in volume and equally enhancing electrode/electrolyte contact for rapid charge and mass transfer. Among the prepared nanocomposites, the Fe3O4(13)@C9 anode delivers an excellent reversible discharge capacity of 1222 mA h g−1 after 150 cycles at a current rate of 100 mA g−1, with a capacity retention of 96.8% compared to the fourth cycle (1262 mA h g−1). At a higher current rate of 1000 mA g−1, the nanocomposite anode offers a superior discharge capacity of 636 mA h g−1 beyond 300 cycles. The present study reveals the use of a 3D mesoporous carbon material as a scaffold for anchoring Fe3O4 nanoparticles with impressive potential as an anode for new-generation lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In this study, proanthocyanidins-functionalized Fe3O4 magnetic nanocomposites were synthesized by the hydrothermal method. The prepared Fe3O4 nanocomposites were characterized by Fourier transform infrared spectrometer (FTIR), X-ray powder diffractometer (XRD), physical property measurement system (PPMS), particle size analyzer, scanning electron microscope (SEM), and transmission electron microscope (TEM). FTIR results indicated that the obtained products were coated with proanthocyanidins. The SEM and TEM results, as well as particle size distribution analysis, revealed that the obtained products were spherical particles with average diameter of 3 2 8. 6 2 ± 2 6. 7 5 nm. XRD and PPMS characterization confirmed that the Fe3O4 nanoparticles have a cubic spinel structure with magnetic properties. The performance of the Fe3O4 nanocomposites for removing organic dyes in an aqueous solution was investigated. The synthesized products were found to be effective on removing various organic dyes, such as Methylene blue (MB), neutral red (NR) and Rhodamine B (RhB), indicating their considerable potential as efficient dyes adsorbents for wastewater treatment. Proanthocyanidins-functionalized Fe3O4 magnetic nanocomposites were synthesized by the hydrothermal method. The obtained Fe3O4 nanocomposites can efficiently remove the organic dyes in an aqueous solution. Proanthocyanidins-functionalized Fe3O4 magnetic nanocomposites had the potential to be developed as efficient dyes adsorbents for wastewater treatment. [ABSTRACT FROM AUTHOR]

In this study, a new type of highly efficient and recyclable magnetic-fluorine-containing polyether composite demulsifier (Fe3O4@G-F) was synthesized by the solvothermal method to solve the demulsification problem of oil–water emulsion. Fe3O4@G-F was successfully prepared by grafting fluorinated polyether onto Fe3O4 and graphene-oxide composites. Fe3O4@G-F was characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Taking the self-made crude-oil emulsion as the experimental object, the demulsification mechanism of the demulsifier and the influence of external factors, such as the temperature and pH value, on the demulsification performance of the demulsifier are discussed. The results show that the demulsification efficiency of the Fe3O4@G-F emulsion can reach 91.38% within 30 min at a demulsifier dosage of 750 mg/L, pH of 6, and a demulsification temperature of 60 °C. In neutral and acidic environments, the demulsification rate of the demulsifier is more than 90%. In addition, Fe3O4@G-F has been proven to have good magnetic effects. Under the action of an external magnetic field, Fe3O4@G-F can be recycled and reused in a two-phase system four times, and the demulsification efficiency is higher than 70%. This magnetic nanoparticle demulsifier has broad application prospects for various industrial and environmental processes in an energy-saving manner. [ABSTRACT FROM AUTHOR]

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In view of ecobenign nature of green synthesis, iron oxide (Fe3O4) nanoflakes are synthesized via a green route. Three different vegetables (spinach, broccoli and pumpkin) extracts were used for the synthesis of Fe3O4 nanoflakes. X-ray diffraction (XRD) analyses confirm the formation of face centered cubic Fe3O4, while SEM analysis revealed the formation of nanoflakes. FTIR also confirm the Fe–O bands at 478 and 590 (cm−1) and the surface plasmon resonance (SPR) was observed at 280 nm. The magnetic properties were also investigated and Fe3O4 prepared using spinach extract shows relatively low saturation magnetization (Ms) of ∼66 emu/g as compared to pumpkin (105 emu/g) and broccoli (130 emu/g) with ∼25Oe coercivity value. The antibacterial activity of Fe3O4 nanoflakes was studied against Escherichia coli and Pseudomonas aeruginosa and a highly promising antibacterial activity was observed. Results revealed that the Fe3O4 nanoflakes prepared via a green route could have potential applications in biomedical field. [ABSTRACT FROM AUTHOR]

Fe3O4 and Fe3O4/NiO heterostructures were successfully prepared by a simple one-step solvothermal method. The morphology of Fe3O4/NiO heterostructures is flower-like spheres composed of nanosheets with a thickness of 10–20 nm. As anode material for lithium-ion batteries (LIBs), the electrochemical performance of the Fe3O4 and Fe3O4/NiO heterostructures are comparatively investigated. At current density of 100 mA g−1, the Fe3O4/NiO heterostructures can maintain 1021 mAh g−1 after 100 cycles. The discharge capacity can still maintain at 500 mAh g−1 and the coulomb efficiency is always stable at 99.6% after 1000 cycles at 1 A g−1. The Fe3O4/NiO heterostructures also have lower impedance and better rate capability, compared with the bare Fe3O4 electrode. Moreover, the electrochemical properties of the Fe3O4/NiO heterostructures can be further improved when the new binder CMC-Li is used. At 100 mA g−1, it can still maintain 1544 mAh g−1 after 100 cycles. These loose-layered nanosheets can effectively alleviate the volume expansion of materials in the process of charge and discharge. Meanwhile, the large surface area can provide more reaction sites. The ultra-thin nanosheet can also reduce the diffusion distance of lithium ions, so that the Fe3O4/NiO heterostructures have excellent performance in lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Magnetic granite (MG), a new and low-cost adsorbent, was prepared by the chemical co-precipitation of Fe2+ and Fe3+ using granite (G), which is a magmatic rock type. The adsorption of the Reactive Black 5 (RB5) dye from aqueous solutions on Fe3O4-modified granite was examined in a batch system. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray fluorescence spectrometry (XRF), X-ray diffractometry (XRD), N2 adsorption–desorption, vibrating-sample magnetometry (VSM), and point-of-zero charge (pHpzc) analysis were used to characterize the prepared MG. Magnetic granite displayed significant magnetization and could be easily separated using external magnets. The maximum adsorption capacity was 29.85 mg/g at 298 K. According to kinetic and isothermal examinations, the pseudo-second-order model and Langmuir isothermal adsorption were the best fit for adsorption. It was found that the enthalpy change ΔH (kJ/mol) was −31.76, and the entropy change ΔS (kJ/mol) was 0.096 for a temperature change of 298–330 K. The ΔG° (kJ/mol) value was negative at all temperatures (298 K, −2.86 kJ/mol; 303 K, −2.85 kJ/mol and 313 K, −1.50 kJ/mol), indicating that the adsorption of RB5 on MG was spontaneous. [ABSTRACT FROM AUTHOR]

The hydrogenated TiO2 coated core-shell structure C/Fe3O4@rGO (H-TiO2/C/Fe3O4@rGO) composite material with oxygen vacancy defects was prepared by a simple method as high-performance anode material for lithium-ion batteries (LIBs). The volume expansion coefficient of TiO2 in the process of Li+ deintercalation is about 4%, which can alleviate the volume expansion of Fe3O4 during charging and discharging, and improve the stability of the anode material structure. At the same time, the lower conductivity of TiO2 (about 1×10-12 S·m-1) is improved by hydrogenation. After 200 cycles, the H-TiO2/C/Fe3O4@rGO specific capacity is 867 mAh·g-1 at a current density of 0.3 A·g-1, and the specific capacity is 505 mAh·g-1 after 700 cycles at a current density of 1 A·g-1, these results is far greater than the theoretical capacity of graphite (372 mAh·g-1). These findings indicate that the H-TiO2/C/Fe3O4@rGO composite materials may be used as a suitable anode material for LIBs.