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This work examines the influence of iron oxide nanoparticles (Fe3O4 NPs) on neutron and gamma-ray radiation shielding characteristics of Portland cement paste. Experimental evaluations were supplemented with theoretical studies using NXCom program. Portland cement pastes with 5, 10, 15, 20, and 30 wt% of nanomagnetite cement replacement were produced. Moreover, rheological, early strength development, compressive strength, and mercury intrusion porosimetry (MIP) tests were performed. The results showed that increasing the amount of Fe3O4 NPs in a mix leads to a gradual increment in measured viscosity and yield stress. High nano-Fe3O4 content substantially impeded the early strength development process and led to a decrement in the 7- and 28-day compressive strength of cement paste. The MIP studies exhibited a gradual increment in total porosity, and average pore volume, as nano-Fe3O4 content was increased. All the macroscopic cross-sections of slow, fast and thermal neutrons constantly increased as a result of the addition of magnetite nanoparticles, with their variations being markedly linear. Similarly, gamma attenuation test results indicated that the addition of Fe3O4 powder enhances the shielding capability of paste in the energy range of interest (0.08–2.614 MeV). In conclusion, Fe3O4 nanoparticles can be successfully used in producing lead-free cementitious composites with improved gamma-ray and neutron shielding properties. However, certain drawbacks related to an increment in matrix porosity and thus a decrement in mechanical performance should be taken into account.

Settling time, system temperature and reductant amount play an important role in the recovery of matte from copper slag. This study investigated the settling behavior of matte particles in copper slag and the effects of the settling time, system temperature, and reductant amount on the macrostructure of slag, microstructure of matte particles, and copper loss. The results showed that the settling behavior of matte particles in slag at the experimental temperature was a process of aggregation and growth. With an increase in settling time and temperature, as well as the addition of an appropriate amount of anthracite, the foaming slag layer of the slowly cooled slag gradually disappeared, while the recovery of matte increased. However, when the amount of anthracite was too high, Fe-Cu alloy formed at the experimental temperature, which resulted in worsened fluidity of the matte in the molten slag and copper loss increased. At the experimental temperature, the settling environment of matte particles in the liquid phase layer was superior to that of the foaming slag layer. The novel idea of using rubber seed oil instead of a traditional fossil reductant to clean the copper slag was put forward. At the temperature of 1250 °C, 4 mL of rubber seed oil was injected, resulting in a settling time of ≥90 min, after which the copper content in the upper part of the slowly cooled slag was less than 0.57 wt.%, reaching the acceptable level of discardable slag in industry.

To substantially prevent electromagnetic threatens, microwave absorbing materials (MAMs) are required to eliminate surplus electromagnetic waves. As a typical MAM, Fe3O4 particles with complex permittivity and permeability have been widely applied due to the coexistence of magnetic loss and dielectric loss. However, the necessary high mass fraction significantly limited its applications, thus Fe3O4 nanostructures have been extensively investigated to overcome this problem. In this work, uniform Fe3O4 nanobelts were prepared by electrospinning and two-step thermal treatment. By controlling the composition and viscosity of the electrospinning precursor solution, Fe3O4 nanobelts with tunable lateral sizes (200 nm–1 μm) were obtained. The samples with low content (only 16.7 wt%) Fe3O4 exhibited wide maximum effective absorbing bandwidths (EAB) over 3 GHz, and Fe3O4 nanobelts with smaller lateral sizes showed a maximum EAB of 4.93 GHz. Meanwhile, Fe3O4 nanobelts with smaller lateral sizes presented superior reflection loss properties, the lowest reflection loss reached −53.93 dB at 10.10 GHz, while the maximum EAB was up to 2.98 GHz. The excellent microwave reflection loss of Fe3O4 nanobelts was contributed to the enhanced synergistic effect of magnetic loss, dielectric loss, and impedance matching, originated from the hierarchically cross-linked networks and shape anisotropies. This study could broaden the practical applications of magnetic absorbers, and provided an approach for the development of shape anisotropic magnetic materials.

Fe3O4/reduced graphene oxide (RGO) composite powders were prepared by solution combustion synthesis method. The effects of fuel type; glycine and urea; on the structure, microstructure, magnetic, and microwave absorption properties were characterized by modern methods. A mixture of α-Fe2O3 and Fe3O4 phases was obtained by the urea fuel, while the glycine fuel led to the pure Fe3O4 phase. The scanning and transmission electron microscopy showed the Fe3O4 nanoparticles were distributed on the ultrathin RGO sheets. With the addition of RGO, the saturation magnetization increased up to 84 emu/g due to the higher amounts of the magnetite phase. The Fe3O4/RGO composite powders synthesized by the urea fuel showed a reflection loss (RL) of −28 dB with effective bandwidth of 1.4 GHz in the C1 band at the matching thickness of 3.7 mm. However, the pristine Fe3O4 powders prepared by the glycine fuel had higher absorption properties, including higher RL of −33 dB and broader bandwidth of 3 GHz in the Ku band at the matching thickness of 1.2 mm. In addition to the higher magnetic and dielectric losses, the higher microwave absorption performance was attributed to the better impedance matching property caused by the porous microstructure.

In this study, the protein stability of hen egg-white lysozymes (HEWL) by Fe3O4 and Fe3O4-coated trehalose (Fe3O4@Tre) magnetic nanoparticles (NPs) is investigated. For this purpose, the co-precipitation method was used to synthesize magnetic NPs. The synthesized NPs were characterized by XRD, FT-IR spectroscopy, FE-SEM, and VSM analysis. In addition, the stability of HEWLs exposed to different NP concentrations in the range of 0.001–0.1 mg mL−1 was investigated by circular dichroism (CD) spectroscopy, fluorescence, and UV-Vis analysis. Based on the results, in the NP concentration range of 0.001–0.04 mg mL−1 the protein structure is more stable, and this range was identified as the range of kosmotropic concentration. The helicity was measured at two concentration points of 0.02 and 0.1 mg mL−1. According to the results, the α-helix at 0.02 mg mL−1 of Fe3O4 and Fe3O4@Tre was increased from 35.5% for native protein to 37.7% and 38.7%, respectively. The helicity decreased to 36.1% and 37.4%, respectively, with increasing the concentration of Fe3O4 and Fe3O4@Tre to 0.1 mg mL−1. The formation of hydrated water shells around protein molecules occurred by using Fe3O4@Tre NPs. Hence, it can be concluded that the trehalose as a functional group along with magnetic NPs can improve the stability of proteins in biological environments.

Considering the risk associated with exposure to benzene and toluene in water resources, researchers have been motivated to conduct studies to remove them from aqueous solutions. Thus, by performing the present study, the potential of Fe3O4/zeolite imidazolate framework nanoparticles (Fe3O4@ZIF-8) was evaluated for the adsorption of benzene and toluene. Accordingly, the solution pH, Fe3O4@ZIF-8 dosage, mixing time, concentration of benzene and toluene, and temperature, were the parameters considered for conducting the batch experiments, for which their effect on adsorption efficiency was evaluated. Our conducted experiments introduced the neutral pH as the best pH range to obtain the maximum removal. Fitting the adsorption data into the various models revealed the aptness of the Langmuir isotherm equation in describing experimental information and highest adsorption capacity; for benzene it was 129.4, 134.2, 137.3, and 148.2 mg g−1, but for toluene it was 118.4, 125.2, 129.6, and 133.1 mg g−1, for temperature 20, 30, 40, and 50 °C, respectively. Using obtained optimal conditions, the adsorption efficiencies of benzene and toluene were obtained to be 98.4% and 93.1%, respectively. Kinetic studies showed acceptable coefficients for PSO kinetics and confirmed its suitability. Also, the recyclability results showed that for six consecutive periods of the adsorption-desorption process, the percentage of removal decreased by only 6% for benzene and toluene. Moreover, calculating thermodynamic parameter changes for benzene and toluene removal confirmed the favorability and spontaneity of the studied process and its endothermic nature. Considering the above findings, Fe3O4@ZIF-8 was found to be an operative adsorbent for removing pollutants.

Nanocomposites comprising magnetic nanoparticles (NPs) embedded in an organic conducting polymer are promising materials that may allow one to exploit synergic effects between the electrically conducting and the magnetically permeable components. Having already shown that magnetite NPs can be conveniently used as a catalyst for the oxidative polymerization of the aniline dimer resulting in NPs embedded in the final composite and how to modulate the magnetic coercivity of the composites, we now turn to investigate how the size of magnetite NPs affects the polymerization and the properties of the final composite. Magnetite NPs of diameter 2.3, 10, and 27 nm turned out to be effective catalysts with cheap oxidants such as H2O2 and O2. Yield data show that the rate-determining step occurs on the NP surface. Extensive characterization shows that the NPs are well-dispersed in the composite with no significant morphological change. The static magnetic properties of the composites are widely different, e.g., the magnetic blocking temperature shifts from 290 K for 27 nm NPs to 54 K for 10 nm NPs, while composites with 2.3 nm NPs are virtually unblocked down to 5 K. The dynamic electromagnetic behavior studied up to the microwave range only shows energy absorptions associated with the ferromagnetic resonance, at frequencies around 1 GHz.

Shigella, a typical and fatal foodborne pathogen with strong infectivity and survivability in foodstuff, demands a simple and sensitive detecting method. In this study, we reported a novel nanoplatform based on biofunctionalized magnetic nanoparticles (MNPs) modified upconversion nanoparticles (UCNPs) for rapid and specific determination of Shigella. Due to base pairing, Shigella aptamer-functionalized horseradish peroxidase (HRP) combined with complementary strand-modified MNPs@UCNPs. In the absence of Shigella, HRP associated with MNPs@UCNPs were magnetically separated, and colorless 3,3′,5,5′-tetramethylbenzidine (TMB) was oxidized into blue oxTMB. The overlap between oxTMB’s absorption peak and MNPs@UCNPs’ emission peak caused the fluorescence quenching at 545 nm. The MNPs@UCNPs fluorescence biosensor was achieved to detect Shigella in 1 h, with a limit of detection of 32 CFU/mL. This work showed a rapid and specific sensing platform and produced satisfactory chicken sample results.

The use of dielectric nanofluids has been recently proposed as a method to improve the insulation system of transformers. It has been widely reported that these liquids present superior dielectric properties than conventional dielectric liquids and have a better behavior as cooling agents. Nevertheless some aspects need to be addressed before these materials are applicable to real equipment. This paper analyzes the interaction between dielectric nanofluids and the cellulose materials that constitute the solid insulation of transformers. The impregnation process of a transformer has been emulated in order to obtain samples of solid insulation impregnated with a Fe3O4 based nanofluid. The samples have been subjected to ICP testing and CryoSEM observation, complemented with the determination of the EDX sprectrum. The interaction between the nanoparticles and the cellulose fibers has been investigated finding that bonds are established between them when cellulose is impregnated with nanofluids. This research was funded by the Spanish Ministry of Economy and Competitiveness. Grant Number DPI2015-71219-C2-2-R and Spanish Ministry of Innovation. Grant Number PID2019-107126RB-C21.

Graphical abstract, Cell responses and mechanical properties are vital for scaffold in bone regeneration. Fe3O4 nanoparticles with excellent magnetism can provide magnetic stimulation for cell growth, while graphene oxide (GO) nanosheets are commonly used as reinforcement phases due to their high strength. However, Fe3O4 or GO is tended to agglomerate in matrix. In present study, a novel co-dispersed Fe3O4-GO nanosystem was constructed through electrostatic self-assembly of positively charged Fe3O4 (pFe3O4) on negatively charged GO nanosheets. In the nanosystem, pFe3O4 nanoparticles and GO nanosheets support each other, which effectively alleviates the π-π stacking between GO nanosheets and magnetic attraction between pFe3O4 nanoparticles. Subsequently, the nanosystem was incorporated into poly L-lactic acid (PLLA) scaffolds fabricated using selective laser sintering. The results confirmed that the pFe3O4-GO nanosystem exhibited a synergistic enhancement effect on stimulating cell responses by integrating the capturing effect of GO and the magnetic simulation effect of pFe3O4. The activity, proliferation and differentiation of cells grown on scaffolds were significantly enhanced. Moreover, the nanosystem also exhibited a synergistic enhancement effect on mechanical properties of scaffolds, since the pFe3O4 loaded on GO improved the efficiency of stress transfer in matrix. The tensile stress and compressive strength of scaffolds were increased by 67.1% and 132%, respectively. In addition, the nanosystem improved the degradation capability and hydrophilicity of scaffolds.

There are impressive efforts in conjunction with improving rheological and filtration properties of Water-Based Drilling Fluids (WBDFs) employing Nano-Particles (NPs). However, NPs’ performance in the presence of different salts has not been well assessed. This study intends to investigate the effect of Fe3O4 NPs on rheological and filtration properties of bentonite-water drilling fluids exposed to NaCl, CaCl2, and MgCl2 salts. To reach the goal specified for this study, three 0.5, 1 and 2 wt% NP concentrations, separately, were added into a salt-free and three salt-contaminated bentonite-water drilling fluids (four base fluids). So, 16 different drilling fluids were prepared for this research. The rheological models obtained by six shear rates, apparent viscosity, plastic viscosity, yield point, gel strength, and cutting carrying ability of all the drilling fluids are described in the paper. Moreover, API fluid losses (under 100 psi differential pressure), the cakes’ thickness, and the cakes’ permeability compared to the same as the salt-free base fluid, are interpreted to evaluate the NPs’ performance on filtration control ability of all the drilling fluids. The results showed that the salts weaken the rheological and filtration properties of the salt-free base fluid, while Fe3O4 NPs sustain and improve the rheological properties of salt-free and salty drilling fluids, significantly. Nano-sized Fe3O4 weakens the filtration properties of the salt-free WBDF, but it is a suitable filtration control agent for salt-contaminated drilling fluids. In a sentence, nano-Fe3O4 is a suitable additive to enhance salty-WBDFs’ performance.

A novel magnetic adsorbent Fe3O4/Ni/NixB nanocomposite was synthesised and used for the removal of Pb(II) from water. the nanocomposite effectively absorbs Pb(II), and because the adsorbent is magnetic, it is easily separated from the solution. in addition, carob and grape seeds, which are sustainable materials, are also used for the removal of Pb(II) for the first time in the literature. Characterisation of the adsorbents was performed using scanning electron microscopy combined with energy dispersive X-Ray spectroscopy (SEM-EDX). the effect of pH on the adsorption efficiency of Pb(II) was investigated. the optimum adsorbent doses were determined as 2.0 g/L for the Fe3O4/Ni/NixB nanocomposite and 4.0 g/L for the carob and the grape seeds. Three commonly used isotherm models: Langmuir, Freundlich and Dubinin-Radushkevich were applied to the experimental data. the batch adsorption equilibrium data of the three adsorbents fitted well to Langmuir isotherms. the maximum capacities for the adsorption of Pb(II) were determined to be 119.0, 25.3 and 24.4 mg/g for the Fe3O4/Ni/NixB nanocomposite, the carob and the grape seeds, respectively. the dimensionless separation factor (R-L) values calculated from the Langmuir isotherm were varied from 0.08 to 1 for three adsorbents. These results demonstrate that the adsorption of Pb(II) on all the adsorbents is favourable. the pseudo-first order, the pseudo-second order and the Weber-Morris intraparticle diffusion kinetic models were used for the identification of the adsorption kinetics of Pb(II) and the correlations of adsorbed Pb(II) with time. the kinetic data is well described with the pseudo-second order kinetic model for all the adsorbents, which indicates that chemisorption plays a dominant role. the adsorption study using a column was successfully applied to real tap water and waste water samples. Also a spiked study (1, 10, 100 mg/L Pb(II)) was also conducted on water samples. As a result, Fe3O4/Ni/NixB nanocomposite, the carob and the grape seeds are efficient adsorbents for the removal of Pb(II) from the water samples.

Makalah ini bertujuan mengkaji kelayakan ekonomi produksi nanopartikel Fe 3 O 4 dari skala laboratorium menjadi skala industri. Evaluasi dilakukan menggunakan 2 model studi kelayakan, yaitu: analisis teknik dan evaluasi ekonomi. Analisis teknik memberikan informasi potensi produksi berskala besar dan hasil proses ini dapat diterapkan menggunakan peralatan yang tersedia secara komersial dan murah. Evaluasi ekonomi dilakukan berdasar perbandingan grafik Cumulative Net Present Value pada keadaan ideal dan grafik pada saat dilakukan perubahan parameter (seperti perubahan nilai kurs dollar, kuantitas produk penjualan, dan besar nilai gaji karyawan). Dari hasil evaluasi, semua perubahan parameter memberikan nilai positif yang menunjukkan bahwa proyek ini layak dijalankan secara komersial dan dalam skala besar. Hal ini karena hasil evaluasi memberikan kestabilan indeks keuntungan pada beberapa perubahan nilai parameter. Studi ini menunjukkan bahwa fabrikasi Fe 3 O 4 dapat memberikan laba yang menjanjikan di negara berkembang dan dapat menarik investor asing untuk bekerja sama dalam fabrikasi Fe 3 O 4 . This paper aims to evaluate the economic feasibility of Fe 3 O 4 nanoparticle production from a laboratory scale to an industrial scale feasibility. The evaluation was conducted using 2 models of feasibility studies, namely: technical analysis and economic evaluation. Technical analysis provides information on the potential for large-scale production and the results of this process can be applied using commercially available and inexpensive equipment. Economic evaluation is based on a comparison of the Cumulative Net Present Value graph in an ideal condition and the graph when parameters changing are made (such as changes in the dollar exchange rate, the quantity of sales products, and the value of employee salaries). From the evaluation results, all parameter changes give a positive value indicating that the project is feasible to run commercially and on a large scale. This is because the evaluation results provide a stable index of profit for some changes in parameter values. This study shows that Fe 3 O 4 fabrication can provide promising profits in developing countries and can attract foreign investors to work together on Fe 3 O 4 fabrication.

The properties of two samples of Fe3O4 magnetic nanoparticles coated with citric acid and oleic acid respectively, have been studied by means of DC magnetic measurements. The analysis has been performed by measuring the Zero Field Cooling (ZFC) and Field Cooling (FC) magnetization curves as a function of the temperature, at 0.01 T applied field. In this framework, the blocking temperature (TB) distribution and the effect of the coatings on the experimentally evaluated samples properties have been analysed. Moreover, the magnetization as a function of the field has been measured at temperatures above TB and the comparison between the results obtained for the two samples has been discussed.

A palladium complex of a dendrimer type ligand of aminoethylacrylamide immobilized onto the mesoporous channels of MCM-41 with magnetic core was prepared and characterized using various techniques such as XRD, TEM, BET, FT-IR, TGA, and VSM. The prepared nanostructured material was found as a magnetically recoverable catalyst for Heck reaction of aryl halides and vinylic C–H. The catalyst is easily recoverable with an external magnet and is reusable with different leaching amounts depending to loading of Pd. A hot filtration test was also performed and gave evidence that Palladium in heterogeneous samples can dissolve and then redeposit on the surface of the support material.

Nanodiamonds with magnetic resonance imaging (MRI) and targeted drug delivery to exert combined effects for biomedical applications have been considered to be an urgent challenge. Herein, a novel bio-nanoarchitectonics (Fe3O4@NDs) with simultaneous imaging and therapeutic capacities was fabricated by covalently conjugating nanodiamonds (NDs) with Fe3O4. Fe3O4@NDs exhibited better biocompatibility and excellent photothermal stability with superb photothermal conversion performance (37.2%). Fe3O4@NDs has high doxorubicin (DOX) loading capacity (193 mg/g) with pH and NIR-responsive release characteristics. Fe3O4@NDs loading DOX showed a combined chemo-photothermal inhibitory effect on the tumor cells. Enhanced T2-weighted MRI contrast toward the tumor, with the assistance of a magnetic field, convinced the Fe3O4@NDs gathered in the tumor more efficiently and could be used for MRI-based cancer diagnosis. Our results revealed an effective strategy to achieve a stimuli-sensitive nanoplatform for multifunctional theranostics by the combined action.

In this study, both wood flour (WF) and wood flour-derived biochar (WFB) were used as supports for Fe3O4 to activate peroxydisulfate (PDS). The role of different carriers was investigated emphatically from the aspects of catalyst properties, the degradation kinetics of bisphenol A (BPA), the effects of important parameters, and the generation of reactive oxygen species (ROS). Results showed that both WF and WFB could serve as good support for Fe3O4, which could control the release of iron into solution and increase the specific surface areas (SSAs). The WFB/Fe3O4 had stronger PDS activation capability than WF/Fe3O4 mainly due to the larger SSA of WFB/Fe3O4 and the PDS activation ability of WFB. Both radical species (•OH and SO4•−) and non-radical pathways, including 1O2 and high-valent iron-oxo species, contributed to the degradation of BPA in the WFB/Fe3O4–PDS process. Moreover, the WFB/Fe3O4 catalyst also showed stronger ability to control the iron release, better reusability, and higher BPA mineralization efficiency than WF/Fe3O4.

A major drawback of nanoparticles (NPs) for biomedical applications is their preferential phagocytosis in immune cells, which can be avoided by surface modifications like PEGylation. Nevertheless, examinations of different polyethylene glycol (PEG) chain lengths on the competence of immune cells as well as possible immunotoxic effects are still sparse. Therefore, primary murine macrophages and dendritic cells were generated and incubated with magnetic nanoporous silica nanoparticles (MNPSNPs) modified with different mPEG chains (2 kDa, 5 kDa, and 10 kDa). Cytotoxicity, cytokine release, and the formation of reactive oxygen species (ROS) were determined. Immune competence of both cell types was examined and uptake of MNPSNPs into macrophages was visualized. Concentrations up to 150 µg/mL MNPSNPs showed no effects on the metabolic activity or immune competence of both cell types. However, ROS significantly increased in macrophages incubated with larger PEG chains, while the concentration of cytokines (TNF-α and IL-6) did not indicate a proinflammatory process. Investigations on the uptake of MNPSNPs revealed no differences in the onset of internalization and the intensity of intracellular fluorescence. The study gives no indication for an immunotoxic effect of PEGylated MNPSNPs. Nevertheless, there is still a need for optimization regarding their internalization to ensure an efficient drug delivery.

In this paper, the luminescent complex Eu(3-thenoyltrifluoroacetonate)3 was integrated with Fe3O4 and gold (Au) nanoparticles to form a multifunctional nanocomposite, Fe3O4/Au/Eu(TTA)3 (FOASET NC), for dual magnetic-photothermal therapy and biomedical imaging. Upon functionalization with amine-NH2, the FOASET NC exhibits a small size of 60–70 nm and strong, sharp emission at λmax = 614 nm, enhanced by surface plasmon resonance (SPR) of Au nanoparticles that provided an effective label for HT29 colorectal cancer cells by fluorescence microscopy imaging. In addition, a hyperthermia temperature (42–46 °C) was completely achieved by using these FOASET NCs in an aqueous solution with three heating modes for (i) Magnetic therapy (MT), (ii) Photothermal therapy (PT), and (iii) Dual magnetic-photothermal therapy (MPT). The heating efficiency was improved in the dual magnetic-photothermal heating mode.

As a novel functional nanomaterial, Fe3O4 magnetic nanoparticles (MNPs) modified by different surfactants have attracted and are attracting worldwide interest. In this research, we introduced two different silane coupling agents to modify Fe3O4 MNPs instead of a single surfactant to achieve complete coating and functionalization. The modification mechanism was also explained. Techniques such as TEM, XRD, FT-IR, TG-DSC, and VSM were applied to characterize the obtained modified Fe3O4 sample. From these techniques, the following information is obtained: The characteristic bands of TEOS and KH-792 were present in the FT-IR spectra and in the XPS plots of modified Fe3O4 MNPs, demonstrating that the silane coupling agents were present in the sample obtained after the modification. The TG analysis of the modified sample showed complete decomposition at 228 °C. The mass ratio of the sample obtained before and after the modification was close to 29:65. The XRD patterns show that the modified Fe3O4 MNPs possessed an identical reverse spinel crystal structure as an unmodified Fe3O4 sample. The modification decreased the saturation magnetization of Fe3O4 MNPs from 70.04 emu/g to 57.41 emu/g and the coating did not change the superparamagnetism of Fe3O4 MNPs.

The rapid purification of biomaterials such as DNA, RNA, and antibodies has attracted extensive attention, and research interest has increased further with the COVID-19 pandemic. In particular, core–shell-structured superparamagnetic nanoparticles have been continuously studied for their application as biopurification materials. It has been reported that Fe3O4@SiO2 nanoparticles are one of the most promising candidates for separating nucleic acids via a simple and rapid process. This study proposed a fabrication method for dual-layered Fe3O4@SiO2 nanoparticles, in which the density of the SiO2 shell was controlled using an intermediate surfactant during the SiO2 coating. After the fabrication of dual-layered Fe3O4@SiO2 nanoparticles, structural, morphological, and magnetic analyses were conducted. The results showed that the Fe3O4 nanoparticles were surrounded by a dense layer 15.6~27.9 nm thick and a porous layer 24.2~44.4 nm thick, and had superparamagnetic properties with high saturated magnetization at room temperature (86.9 emu/g). Then, the optimal conditions for the biopurification material were suggested based on analysis of the selective separation of plasmid DNA.

In recent research, the composite of Fe3O4 and metal-organic frameworks have shown great potential in removing potentially toxic metals from water. We conducted the adsorption studies of potentially toxic metal ions (Cu2+, Co2+ and Cd2+) using the composite of Fe3O4 and zeolitic imidazole framework-8 (Fe3O4@ZIF-8) for the first time. The solvothermal technique was used to synthesize the Fe3O4. The magnetic ZIF-8 offers high thermal stability, greater adsorption surface, good removability, and high chemical and thermal stability. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized samples. The SEM and XRD results revealed the high purity and structural integrity of ZIF-8 crystallites. To remove potentially toxic metals (Cu2+, Co2+ and Cd2+), the influence of adsorbent dosage, contact time, pH, and adsorbate concentration on the adsorption performance of Fe3O4@ZIF-8 was investigated. The Langmuir isotherm accurately represented the adsorption processes, with absorption magnitudes of Fe3O4@ZIF-8 determined to be 46.82 mg g−1, 71.29 mg g−1 and 54.49 mg g−1 for Cu2+, Co2+ and Cd2+, respectively. According to the adsorption mechanism analysis, the primary Cu2+, Co2+ and Cd2+ removal methods of Fe3O4@ZIF-8 were ion exchange and coordination bonds. The uptake capacity of Cu2+, Co2+ and Cd2+ solution by Fe3O4@ZIF-8 were not significantly affected by the presence of counter ions. The material exhibited superior regenerative properties for Cu2+, Co2+ and Cd2+ ions from water for up to three cycles. This study concluded that the Fe3O4@ZIF-8 could be a viable candidate for eliminating potentially toxic metals (Cu2+, Co2+ and Cd2+). HIGHLIGHTS Adsorption study of Cu2+, Co2+, and Cd2+ on composite of Fe3O4 and ZIF-8.; The effect of adsorbent dose, contact time, pH and concentration influence on the adsorption performance of Fe3O4@ZIF-8 was studied.; The primary Cu2+, Co2+, and Cd2+ removal methods of Fe3O4@ZIF-8 were ion exchange and coordination bonds.; Fe3O4@ZIF-8 could be a viable candidate for eliminating Cu2+, Co2+, and Cd2+ from wastewater.

The biological synthesis of nanoparticles is emerging as a potential method for nanoparticle synthesis due to its non-toxicity and simplicity. In the present study, a bacterium resistant to heavy metals was isolated from a metal-contaminated site and we aimed to report the synthesis of Fe3O4 nanoparticles via co-precipitation using bacterial exopolysaccharides (EPS) derived from Enterococcus faecalis_RMSN6 strains. A three-variable Box–Behnken design was used for determining the optimal conditions of the Fe3O4 NPs synthesis process. The synthesized Fe3O4 NPs were thoroughly characterized through multiple analytical techniques such as XRD, UV-Visible spectroscopy, FTIR spectroscopy and finally SEM analysis to understand the surface morphology. Fe3O4 NPs were then probed for the Cr(VI) ion adsorption studies. The important parameters such as optimization of initial concentration of Cr(VI) ions, effects of contact time, pH of the solution and contact time on quantity of Cr(VI) adsorbed were studied in detail. The maximum adsorption capacity of the nanoparticles was found to be 98.03 mg/g. The nanoparticles could retain up to 73% of their efficiency of chromium removal for up to 5 cycles. Additionally, prepared Fe3O4 NPs in the concentration were subjected to cytotoxicity studies using an MTT assay. The investigations using Fe3O4 NPs displayed a substantial dose-dependent effect on the A594 cells. The research elucidates that the Fe3O4 NPs synthesized from EPS of E. faecalis_RMSN6 can be used for the removal of heavy metal contaminants from wastewater.

In this study, the effect of molarity on the structural, magnetic, and heat dissipation properties of magnetite nanoparticles (MNPs) was investigated to optimise the parameters for potential application in magnetic hyperthermia therapy (MHT). MHT works based on the principle of local temperature rise at the tumour site by magnetic iron oxide nanoparticles (MIONPs) with the application of an alternating magnetic field. MHT is a safe method for cancer treatment and has minimal or no side effects. Magnetite (Fe3O4) is the best material among MIONPs to be applied in local MHT due to its biocompatibility and high saturation magnetisation value. MNPs were prepared by co-precipitation at varying molarity. Structural characterisation was performed via X-ray powder diffraction (XRD) for crystalline structure analysis and field-emission scanning electron microscopy (FESEM) for morphology and particle size analysis. Measurement of the magnetic properties of the as-synthesised MNPs was carried out using a vibrating sample magnetometer (VSM). Power loss (P) was determined theoretically. The increase in molarity resulted in significant effects on the structural, magnetic, and heat dissipation properties of MNPs. The particle size and saturation magnetisation (Ms) decreased with the gradual addition of base but increased, together with crystallinity, with the gradual addition of iron source. M3 recorded the smallest crystalline size at 3.559 nm. The sample with the highest molarity (M4) displayed the highest heat generation capacity with a p value of up to 0.4056 W/g. High p values at the nano-scale are crucial, especially in local MHT, for effective heat generation, thus proving the importance of molarity as a vital parameter during MNP synthesis.

Conventional liquids have poor thermal conductivity, thus limiting their use in engineering. Therefore, scientists and researchers have created nanofluids, which consist of nanoparticles dispersed in a base fluid, to improve heat transfer properties in various fields, such as electronics, medicine, and molten metals. In this study, we examine the micropolar nanofluid flow in a stagnation region of a stretching/shrinking sheet by employing the modified Buongiorno nanofluid model. The nanofluid consists of magnetite (Fe3O4) nanoparticles. The similarity equations are solved numerically using MATLAB software. The solution is unique for the shrinking strength λ≥−1. Two solutions are found for the limited range of λ when λc

Improving the evaporation rate of solar steam generation (SSG) has always been a research hotspot to solve the shortage of water resources. Using cotton, Fe3O4, polyvinyl alcohol (PVA) and diatomite (DM) as raw materials, DM/PVA/Fe3O4@cotton composites with both firmness and hydrophilicity were prepared. Fe3O4 has a wide range of light absorption characteristics and good photothermal conversion performance, and is an ideal photothermal conversion material. PVA enhances the adhesion between Fe3O4, cotton and DM and enhances the hardness of the sample and the internal porous structure. The existence of DM greatly improves the hydrophilicity of the sample, ensuring that the water in the lower layer can be continuously transported to the surface of the sample, and DM makes the surface of the sample rough, which reduces the reflection of sunlight and improves the efficiency of light heat conversion. Under one-sun irradiation, the temperature of the sample surface increases by 52.6 °C, the evaporation rate can reach 1.32 kg m−2 h−1 and the evaporation efficiency is 82.9%. Using this sample as the photothermal conversion layer of the SSG device, the removal rate of salt ions in seawater is more than 98% and the removal rate of heavy metal ions in sewage is close to 100%. This work provides a new idea and design method for SSG in the field of seawater desalination and sewage treatment.

Reported here is the design of an electrochemical sensor for dopamine (DA) based on a screen print carbon electrode modified with a sulphonated polyether ether ketone-iron (III) oxide composite (SPCE-Fe3O4/SPEEK). L. serica leaf extract was used in the synthesis of iron (III) oxide nanoparticles (Fe3O4NPs). Successful synthesis of Fe3O4NP was confirmed through characterization using Fourier transform infrared (FTIR), ultraviolet–visible light (UV–VIS), X-ray diffractometer (XRD), and scanning electron microscopy (SEM). Cyclic voltammetry (CV) was used to investigate the electrochemical behaviour of Fe3O4/SPEEK in 0.1 M of phosphate buffer solution (PBS) containing 5 mM of potassium ferricyanide (III) solution (K3[Fe(CN)6]). An increase in peak current was observed at the nanocomposite modified electrode SPCE-Fe3O4/SPEEK) but not SPCE and SPCE-Fe3O4, which could be ascribed to the presence of SPEEK. CV and square wave voltammetry (SWV) were employed in the electroxidation of dopamine (0.1 mM DA). The detection limit (LoD) of 7.1 μM and 0.005 μA/μM sensitivity was obtained for DA at the SPCE-Fe3O4/SPEEK electrode with concentrations ranging from 5–50 μM. LOD competes well with other electrodes reported in the literature. The developed sensor demonstrated good practical applicability for DA in a DA injection with good resultant recovery percentages and RSDs values.

In this work, different pretreatment methods for algae proved to be very effective in improving cell wall dissociation for biogas production. In this study, the Ulva intestinalis Linnaeus (U. intestinalis) has been exposed to individual pretreatments of (ultrasonic, ozone, microwave, and green synthesized Fe3O4) and in a combination of the first three mentioned pretreatments methods with magnetite (Fe3O4) NPs, (ultrasonic-Fe3O4, ozone-Fe3O4 and microwave-Fe3O4) in different treatment times. Moreover, the green synthesized Fe3O4 NPs has been confirmed by FTIR, TEM, XRD, SEM, EDEX, PSA and BET. The maximum biogas production of 179 and 206 mL/g VS have been attained when U. intestinalis has been treated with ultrasonic only and when combined microwave with Fe3O4 respectively, where sediment were used as inoculum in all pretreatments. From the obtained results, green Fe3O4 NPs enhanced the microwave (MW) treatment to produce a higher biogas yield (206 mL/g VS) when compared with individual MW (84 mL/g VS). The modified Gompertz model (R2 = 0.996 was appropriate model to match the calculated biogas production and could be used more practically to distinguish the kinetics of the anaerobic digestion (AD) period. The assessment of XRD, SEM and FTIR discovered the influence of different treatment techniques on the cell wall structure of U. intestinalis.

almessiere, munirah a/0000-0003-1651-3591; Slimani, Yassine/0000-0002-2579-1617; Baykal, Abdulhadi/0000-0002-5205-0937; Demirci, Tuna/0000-0001-8933-4944; Tombuloglu, Huseyin/0000-0001-8546-2658 WOS: 000494768600001 This study investigates (i) in planta uptake and transfer of magnetic nanoparticles (MNPs) in the plant body and (ii) impact of MNPs on plant nutrition. For these purposes, barley (Hordeum vulgare L.) seedlings were subjected by varied MNP doses (125 to 1000 mg L-1 of CoNd0.2Fe1.8O4) for 3 weeks in a hydroponic system. Plant tissues (root and leaf) were analyzed by using vibrating sample magnetometer (VSM) and inductively coupled plasma optical emission spectrometer (ICP-OES) techniques to understand MNPs' uptake and translocation in the plant body, and plant nutrition status as well. Elemental composition and magnetic behavior analyses of plant parts proved that MNPs, sized in 8.4 +/- 0.05 nm, are uptaken by the plant roots and led to an increase in iron (Fe), neodymium (Nd), and cobalt (Co) contents of leaves (p < 0.005). However, compared with the untreated control, the amount of some macro- and micro-elements (K, Ca, Mg, Mn, and P) are declined in the leaf by increased MNP doses (p < 0.05). Root-to-leaf translocation index (%) of the elements were dramatically decreased, except the one for Fe which increased from 25 (control) to 55% in 1000 mg L-1 condition. Accordingly, MNPs are uptaken by the plant roots and transferred to the leaves. However, it suppresses the translocation of essential nutrients. This finding shows that MNPs used in this study is detrimental for plant mineral nutrition. Besides, the VSM technique coupled with ICP-OES enables to track MNPs in the plant body. Imam Abdulrahman Bin Faisal University (IAU) [2018-139-IRMC] The authors would like to the Deanship of Scientific Research (DSR) fund of Imam Abdulrahman Bin Faisal University (IAU) with 2018-139-IRMC project number.

In this work, a hot-melt adhesive used by automotive industries for bonding plastic components has been modified with three different percentages of nanofiller (iron oxide) in order to make the adhesive electromagnetically sensitive and to perform adhesive joint separations. Fe3O4 particles with a weight concentration of 3%, 5% and 10% were embedded in the adhesive matrix. Single Lap Joint (SLJ) tests showed that a slight increase of the maximum load and a more ductile behaviour are obtained. The sensitivity of these modified adhesive performance to the induction heating process was studied with respect to some relevant parameters: the current (or power), the frequency of the electromagnetic induction field and the shape of the coil. Furthermore, the diameter of the hollow copper coil was modified in order to understand whether the coil temperature has an effect on the separation time. The separation time, that is an index of the time needed to reach the melt of the adhesive and the consequent SLJ separation, together with the temperature profile of the adhesives have been used to evaluate the sensitivity of these adhesives to the process parameters. The analysis on the temperature and separation time showed that the most influencing parameter is the frequency of the electromagnetic induction field. As expected, also the shape of the coil influences the separation time, in particular, the adhesive joint separated with the pancake coil showed lower values of the separation time compared to the solenoidal coils. Scanning Electron Microscope (SEM) showed that iron oxide particles tend to form small agglomerate that resulted well dispersed in the adhesive matrix. Thermogravimetric analysis (TGA) was used to verify that the separation procedure do not degrades these modified adhesives.

Today, cancer treatment is an important issue in the medical world due to the challenges and side effects of ongoing treatment procedures. Current methods can be replaced with targeted nano-drug delivery systems to overcome such side effects. In the present work, an intelligent nano-system consisting of Chitosan (Ch)/Gamma alumina (γAl)/Fe3O4 and 5-Fluorouracil (5-FU) was synthesized and designed for the first time in order to influence the Michigan Cancer Foundation-7 (MCF-7) cell line in the treatment of breast cancer. Physico-chemical characterization of the nanocarriers was carried out using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), dynamic light scattering (DLS), and scanning electron microscopy (SEM). SEM analysis revealed smooth and homogeneous spherical nanoparticles. The high stability of the nanoparticles and their narrow size distribution was confirmed by DLS. The results of the loading study demonstrated that these nano-systems cause controlled, stable, and pH-sensitive release in cancerous environments with an inactive targeting mechanism. Finally, the results of MTT and flow cytometry tests indicated that this nano-system increased the rate of apoptosis induction on cancerous masses and could be an effective alternative to current treatments.

The synthesis of magnetic particles triggers the interest of many scientists due to their relevant properties and wide range of applications in the catalysis, nanomedicine, biosensing and magnetic separation fields. A fast synthesis of iron oxide magnetic particles using an eco-friendly and facile microwave-assisted solvothermal method is presented in this study. Submicron Fe3O4 spheres were prepared using FeCl3 as an iron source, ethylene glycol as a solvent and reductor and sodium acetate as a precipitating and nucleating agent. The influence of the presence of polyethylene glycol as an additional reductor and heat absorbent was also evaluated. We reduce the synthesis time to 1 min by increasing the reaction temperature using the microwave-assisted solvothermal synthesis method under pressure or by adding PEG at lower temperatures. The obtained magnetite spheres are 200–300 nm in size and are composed of 10–30 nm sized crystallites. The synthesized particles were investigated using the XRD, TGA, pulsed-field magnetometry, Raman and FTIR methods. It was determined that adding PEG results in spheres with mixed magnetite and maghemite compositions, and the synthesis time increases the size of the crystallites. The presented results provide insights into the microwave-assisted solvothermal synthesis method and ensure a fast route to obtaining spherical magnetic particles composed of different sized nanocrystallites.

A novel three-dimensional graphene-like networks material (3D-GLN) exhibiting the hierarchical porous structure was fabricated with a large-scale preparation method by employing an ion exchange resin as a carbon precursor. 3D-GLN was first studied as the effective microwave absorbing material. As indicated from the results of the electromagnetic parameter tests, and the minimum reflection loss (RL) of the 3D-GLN reached −34.75 dB at the frequency of 11.7 GHz. To enhance the absorption performance of the nonmagnetic 3D-GLN, the magnetic Fe3O4 nanoparticles were loaded on the surface of the 3D-GLN by using the hydrothermal method to develop the 3D-GLN/Fe3O4 hybrid. The hybrid exhibited the prominent absorbing properties. Under the matching thickness of 3.0 mm, the minimum RL value of hybrid reached −46.8 dB at 11.8 GHz. In addition, under the thickness range of 2.0–5.5 mm, the effective absorption bandwidth (RL < 10 dB) was 13.0 GHz, which covered part of the C-band and the entire X-band, as well as the entire Ku-band. The significant microwave absorption could be attributed to the special 3D network structure exhibited by the hybrid and the synergistic effect exerted by the graphene and the Fe3O4 nanoparticles. As revealed from the results, the 3D-GLN/Fe3O4 hybrid could be a novel microwave absorber with promising applications.

The degradation of bisphenol A (BPA) by Fe3O4/persulfate system was investigated in aqueous solution. The influences of the initial concentrations of Fe3O4, persulfate (PS) and BPA, pH value, and initial reaction temperature on BPA removal were studied. The radical species was investigated by adding excessive dose of scavenger (methanol (MeOH) and tert-butanol (TBA)) into Fe3O4/PS system for the purpose of radical scavenging. The degradation products of BPA were detected by gas chromatography-mass spectrometry (GC-MS). The recyclability of Fe3O4 was also evaluated. The BPA removal rate of 80.7% was achieved under the following conditions: [BPA]0 = 1 mg L-1, [PS]0 = 0.2 mM, [Fe3O4]0 = 0.1 g L-1, T0 = 20 ± 1 ºC, pH0 = 6.8 ± 0.2. The results confirmed that the main free radicals in the reaction process were sulfate radicals, followed by hydroxyl radicals. Some intermediate products of BPA degradation, such as phenols, benzoquinones and benzoic acid were identified by GC-MS.

Natural coagulants from plants resources have gained a lot of attention as it is renewable, biodegradable, non-hazardous, lower cost, and less sludge generated compared to chemical coagulants. However there are still some drawbacks, namely long settling time and possible increase of dissolved organic carbon in the treated water. In this paper we tried to address these drawbacks by utilizing citrate modified Fe3O4 to adsorb protein from Leucaena leucocephala as the active coagulating agent. The effect of trisodium citrate concentration and protein adsorption pH to the adsorbed protein was investigated. It was found that the trisodium citrate concentration of 0.5 M and pH 4.0 gave the highest protein adsorption. The obtained magnetic coagulant was furthermore characterized using Scanning Electron Microscopy, X-ray Diffraction, Fourier Transform Infrared Spectroscopy, and Transmission Electron Microscopy to observe the characteristics before and after protein adsorption. Furthermore, the effect of pH (2 to 10) and coagulant dosage (60 to 600 mg L-1) to the removal of synthetic Congo red wastewater and sludge volume formation was investigated. It was found that pH 3 was the best pH for coagulation due to charge neutralization mechanism of leucaena protein. Furthermore the highest removal was obtained at dosage 420 mg L-1 with 80% removal. This result was comparable with crude extract of leucaena with half settling time (20 min) and lower increase of permanganate value, indicating lower increase of dissolved organics in the treated water.

Metal-oxide nanoparticles are regarded as favorable candidates for different device applications including gas sensors. Decoration of nanoparticles with smaller ones of different types enables taking advantage of the physical and chemical characteristics of both core and decorate nanoparticles. Fe3O4 nanoparticles decorated with CuO are produced in this work by a coprecipitation method and investigated for their application for H2S gas sensor devices. The average size of Fe3O4 nanoparticles is 33.33∓5.55nm while the average grain size of the CuO nanoparticles is 9.72∓1.39nm. Gas sensors are fabricated by depositing dispersed nanoparticles on substrates with pre-printed interdigitated electrodes. Impedance spectroscopy is utilized to investigate the electrical characteristics of fabricated devices, where their activation energy is evaluated to 0.386±0.076eV. The fabricated sensors are found to be selective to H2S and sensitive to low concentrations, as low as 1.0 ppm, with minimum response time of 1.0 min. The produced sensors indicate potential for field applications due to their various features that include simplified and practical fabrication procedure, low power needs, high sensitivity, reasonable response time, and magnetic properties of nanoparticles that facilitate their recycling. Qatar University

A nanoscale Fe3O4-biochar (Fe-BC) composite material was prepared using hazelnut shell (HNS) biochar and FeCl2. Biochar was prepared by phosphoric acid (H3PO4)-assisted pyrolysis (BCA) and H3PO4 + microwave (MW)-assisted pyrolysis (BCAMW) of HNS at 500 ◦C. Biochar produced in the presence of H3PO4 exhibited a larger surface area (almost 1300 m2/g) and total pore volume (1.29 cm3/g). Irrespective of activation with MW, Fe3O4 nanoparticles formed on the biochar and its surface area decreased weakly due to iron loading. Based on the temperature- programmed desorption of oxygen (O2-TPD) and temperature-programmed reduction with hydrogen (H2-TPR) results, the reduction of iron and desorption of oxygen from Fe3O4 can be facilitated by the presence of biochar. The estimated crystal size of Fe3O4 could be controlled by pores of biochar. A glassy carbon (GC) electrode coated with Fe-BC was used for the detection of H2O2. The highest H2O2 sensing was measured on Fe-BCAMW having mesoporous structure. After optimization, it was found that H2O2 detection of Fe-BC elec- trocatalysts is linear in the range of 0.5–10 mM. Interference effects of L-cystine, ascorbic acid and urea in H2O2 detection along with detection hydrogen peroxide in milk samples were studied and Fe-BCAMW showed excellent selectivity. Sensitivity and reproducibility results showed that Fe-BC samples produced are promising material in the measurement of H2O2., Sivas Cumhuriyet University Research Foundation (M-778).

Ultrathin magnetic materials with room-temperature ferromagnetism/ferrimagnetism hold great potential in spintronic applications. In this work, we report the successful controllable growth of Fe3O4 thin films using a facile chemical vapor deposition method. Room-temperature ferrimagnetism was maintained in the as-grown Fe3O4 thin films down to 4 nm. Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy analysis were conducted to reveal the structure and quality of the Fe3O4 film. Magnetization measurement showed ferrimagnetic hysteresis loops in all Fe3O4 thin films. A saturation magnetization of 752 emu/cm3 was observed for the 4 nm Fe3O4 film, which was higher than that of bulk Fe3O4 materials (480 emu/cm3). Additionally, the Verwey transition at ~120 K was visible for the Fe3O4 thin films. This work provides an alternative method of synthesizing ferrimagnetic ultrathin films for electronic, spintronic, and memory device applications.

A nanometric hybrid system consisting of a Fe3O4 magnetic nanoparticles modified through the growth of Fe-based Metal-organic frameworks of the MIL (Materials Institute Lavoiser) was developed. The obtained system retains both the nanometer dimensions and the magnetic properties of the Fe3O4 nanoparticles and possesses increased the loading capability due to the highly porous Fe-MIL. It was tested to load, carry and release temozolomide (TMZ) for the treatment of glioblastoma multiforme one of the most aggressive and deadly human cancers. The chemical characterization of the hybrid system was performed through various complementary techniques: X-ray-diffraction, thermogravimetric analysis, FT-IR and X-ray photoelectron spectroscopies. The nanomaterial showed low toxicity and an increased adsorption capacity compared to bare Fe3O4 magnetic nanoparticles (MNPs). It can load about 12 mg/g of TMZ and carry the drug into A172 cells without degradation. Our experimental data confirm that, after 48 h of treatment, the TMZ-loaded hybrid nanoparticles (15 and 20 μg/mL) suppressed human glioblastoma cell viability much more effectively than the free drug. Finally, we found that the internalization of the MIL-modified system is more evident than bare MNPs at all the used concentrations both in the cytoplasm and in the nucleus suggesting that it can be capable of overcoming the blood-brain barrier and targeting brain tumors. In conclusion, these results indicate that this combined nanoparticle represents a highly promising drug delivery system for TMZ targeting into cancer cells.

Background: Treatment methods for cancer that are widely being utilized affect both normal and cancerous cells. We report synthesis polyethylene glycol (PEG)-coated Fe3O4 nanoparticles (NPs) and its characteristic properties and appraise its potential as a promising radiation sensitizer candidate in radiotherapy that improves cancer treatment and reduces side effects of radiation. Materials and methods: PEG-coated Fe3O4 NPs were synthesized by chemical coprecipitation method and characterized by studying their size, structure, functional group, stability, magnetization, and cytotoxicity using different techniques. X-ray powder diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis results show that Fe3O4 NPs have been functionalized with PEG molecules during the course of synthesis. Results Synthesized NPs have good stability based on zeta-potential study. Dynamic light-scattering results reveal that PEG-coated Fe3O4 has a greater hydrodynamic size than bare Fe3O4. Transmission electron microscopy (TEM) micrograph exhibited that NPs are roughly spherical with size in range of 10–20 nm. Saturation magnetization value of PEG-coated and bare Fe3O4 also confirms coating and shows superparamagnetic behavior. Cytotoxicity evaluation study indicated that PEG-coated Fe3O4 is biocompatible on L929 and toxic on Michigan Cancer Foundation-7 (MCF-7) (breast cancer cells). Conclusion: These characterized properties of PEG-coated Fe3O4 NPs show that it could be used as a potential radiosensitizer candidate in radiotherapy to significantly improve cancer treatment and minimize painful side effects of radiation.

Present-day science indicates that developing sensors with excellent sensitivity and selectivity for detecting early signs of diseases is highly desirable. Electrochemical sensors offer a method for detecting diseases that are simpler, faster, and more accurate than conventional laboratory analysis methods. Primarily, exploiting non-noble-metal nanomaterials with excellent conductivity and large surface area is still an area of active research due to its highly sensitive and selective catalysts for electrochemical detection in enzyme-free sensors. In this research, we successfully fabricate Metal-Organic Framework (MOF) FeBDC-derived Fe3O4 for non-enzymatic electrochemical detection of glucose. FeBDC synthesis was carried out using the solvothermal method. FeCl2.4H2O and Benzene-1,4-dicarboxylic acid (H2BDC) are used as precursors to form FeBDC. The materials were further characterized utilizing X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier-Transform Infrared Spectroscopy (FTIR). The resulting MOF yields good crystallinity and micro-rod like morphology. Electrochemical properties were tested using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) with a 0.1 M of Phosphate Buffer Saline (PBS pH 7.4) solution as the supporting electrolyte. The measurement results show the reduction and oxidation peaks in the CV curve of FeBDC, as well as Fe3O4. Pyrolysis of FeBDC to Fe3O4 increases the peak of oxidation and reduction currents. The Fe3O4 sample obtained has a sensitivity of 4.67 &micro, A mM&minus, 1.cm&minus, 2, a linear range between 0.0 to 9.0 mM, and a glucose detection limit of 15.70 &micro, M.

Background Photo-neutrons are produced at the head of the medical linear accelerators (linac) by the interaction of high-energy photons, and patients receive a whole-body-absorbed dose from these neutrons. The current study aimed to find an efficient shielding material for fast neutrons. Methods Nanoparticles (NPs) of Fe3O4 and B4C were applied in a matrix of silicone resin to design a proper shield against fast neutrons produced by the 18 MeV photon beam of a Varian 2100 C/D linac. Neutron macroscopic cross-sections for three types of samples were calculated by the Monte Carlo (MC) method and experimentally measured for neutrons of an Am-Be source. The designed shields in different concentrations were tested by MCNPX MC code, and the proper concentration was chosen for the experimental test. A shield was designed with two layers, including nano-iron oxide and a layer of nano-boron carbide for eliminating fast neutrons. Results MC simulation results with uncertainty less than 1% showed that for discrete energies and 50% nanomaterial concentration, the macroscopic cross-sections for iron oxide and boron carbide at the energy of 1 MeV were 0.36 cm− 1 and 0.32 cm− 1, respectively. For 30% nanomaterial concentration, the calculated macroscopic cross-sections for iron oxide and boron carbide shields for Am-Be spectrum equaled 0.12 cm− 1 and 0.15 cm− 1, respectively, while they are 0.15 cm− 1 and 0.18 cm− 1 for the linac spectrum. In the experiment with the Am-Be spectrum, the macroscopic cross-sections for 30% nanomaterial concentration were 0.17 ± 0.01 cm− 1 for iron oxide and 0.21 ± 0.02 cm− 1 for boron carbide. The measured transmission factors for 30% nanomaterial concentration with the Am-Be spectrum were 0.71 ± 0.01, 0.66 ± 0.02, and 0.62 ± 0.01 for the iron oxide, boron carbide, and double-layer shields, respectively. In addition, these values were 0.74, 0.69, and 0.67, respectively, for MC simulation for the linac spectrum at the same concentration and thickness of 2 cm. Conclusion Results achieved from MC simulation and experimental tests were in a satisfactory agreement. The difference between MC and measurements was in the range of 10%. Our results demonstrated that the designed double-layer shield has a superior macroscopic cross-section compared with two single-layer nanoshields and more efficiently eliminates fast photo-neutrons.

In order to develop a low-cost, fast, and efficient adsorbent, the fish bone charcoal B600 prepared at 600 °C was modified by chitosan (Cs) and Fe3O4 to produce the material Cs-Fe3O4-B600. Results showed that Cs-Fe3O4-B600 had magnetic responsiveness and can achieve solid–liquid separation, macropores disappeared, pore volume and specific surface area are increased, and amino functional groups appear on the surface. The adsorption process of Cd(II) by Cs-Fe3O4-B600 conformed best to the pseudo-second order kinetics model and the Langmuir model, respectively. The behavior over a whole range of adsorption was consistent with chemical adsorption being the rate-controlling step, which is a very fast adsorption process, and the isothermal adsorption is mainly monolayer adsorption, which belongs to favorable adsorption. In addition, the saturated adsorption capacity obtained for the Cs-Fe3O4-B600 to Cd(II) was 64.31 mg·g−1, which was 1.7 times than B600. The structure and morphology of Cs-Fe3O4-B600 were characterized through SEM-EDS, TEM, FTIR, and XRD, indicating that the main mechanism of Cs-Fe3O4-B600 and Cd(II) is mainly the complexation of amino groups, and it also includes part of the ion exchange between Cd(II) and Fe3O4. Therefore, Cs-Fe3O4-B600 can be employed as an effective agent for remediation of Cd contaminated water.

Background Magnetic nanoparticles (MNPs) loaded by various active compounds can be used for targeted drug delivery. Objectives: In the present study, the Fe3O4 magnetic nanoparticles that contained gentamicin were prepared and their antibacterial activities were studied. Materials and Methods MNPs containing gentamicin (G@SA-MNPs) were prepared using sodium alginate (SA) as a surface modifier. After and before coating, the prepared MNPs were characterized using transmission electron microscopy (TEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM). Finally, the antibacterial effect of the MNPs was investigated by a conventional serial agar dilution method. Results Particle size distribution analysis showed that the size of MNPs, before and after coating, was in the range of 1–18 nm and 12–40 nm, respectively. The magnetization curve of G@SA-MNPs (with saturation magnetization of 27.9 emu.g-1) confirmed ferromagnetic property. Loading gentamicin on the surface of MNPs was qualitatively verified by FTIR spectrum. Quantitative analysis measurements indicated the gentamicin loading on SA-MNPs as 56.7 ± 5.4%. The measured MICs of G@SA-MNPs for Pseudomonas aeruginosa (PTTC 1574) was 1.28 µg.mL-1. The sub-MIC (0.64 µg.mL-1) concentration of G@SA-MNPs in nutrient broth could successfully inhibit the growth of P. aeruginosa for 14 hours. Conclusions Loading gentamicin on the SA-MNPs exhibited reasonable antibacterial effects against P. aeruginosa.

A direct release of dye wastewater to a water environment without pre-treatment could cause negative impacts. To solve them, an effective method for degrading wastewater contaminants is needed. In this research, the Fenton reaction using Fe3O4 catalyst for removal of wastewater contaminants taken from a traditional fabrics industry was studied. For this purpose, reaction temperature was varied in the range of 27–90°C. Furthermore, catalyst concentration was also varied in the range of 2–6 g/L solution. The results showed that increasing both temperature and catalyst concentration will increase the performance of the Fenton reaction in degrading wastewater contaminants. The contaminant degradation was measured by detecting chemical oxygen demand and inspecting the color of wastewater. The highest reduction of color intensity was 98.96% at 90°C temperature and 2 g Fe3O4/L solution.

In this study, two kinds of composites with the structure of graphene oxide (GO) sheets wrapped magnetic nanoparticles were investigated on their regeneration. The composites have a similar core-shell structure, but the interactions between the core and shell are quite different, which are electrostatic and covalent. They were characterized by scanning/transmission electron microscopy, power X-ray diffraction, and vibrating sample magnetometer analysis. Their morphologies and structures of the samples had been revealed using methylene blue and Pb(II) as adsorbates during regeneration. The results showed that the composites with covalent bonding interaction could maintain a stable core-shell structure and present a good regeneration performance for adsorption-desorption of methylene blue and Pb(II). The composites with electrostatic interaction could approximately preserve its core-shell structure and could be recyclable for adsorption-desorption of methylene blue, however, they would disintegrate its core-shell structure during adsorption/desorption of Pb(II), thus greatly decreasing their regeneration performance. The regeneration mechanisms of the composites were analyzed, which could provide a useful theoretical guide to design the GO sheets wrapped magnetic nanoparticles composites.

Background: The emergence of two-dimensional MXenes has spurred their versatile applications in broad fields, but the exploring of novel MXene-based family members and their potential applications in theranostic nanomedicine (concurrent diagnostic imaging and therapy) have been rarely explored. In this work, we report the construction of a novel superparamagnetic MXene-based theranostic nanoplatform for efficient breast-cancer theranostics, which was based on intriguing tantalum carbide (Ta4C3) MXene and its further rational surface-superparamagnetic iron-oxide functionalization (Ta4C3-IONP-SPs composite MXenes) for efficient breast-cancer theranostic. Methods: The fabrication of ultrathin Ta4C3 nanosheets was based on an exfoliation strategy and superparamagnetic iron oxide nanoparticles were in-situ grown onto the surface of Ta4C3 MXene according to the redox reaction of MXene. Ta4C3-IONP MXenes were modified with soybean phospholipid (SP) to guarantee high stability in physiological conditions. The photothermal therapy, contrast-enhanced CT, T2-weighted magnetic resonance imaging and the high biocompatibility of these composite nanosheets have also been evaluated in vitro at cellular level and in vivo on mice breast tumor allograft tumor model. Results: The Ta component of Ta4C3-IONP-SPs exhibits high performance for contrast-enhanced CT imaging because of its high atomic number and high X-ray attenuation coefficient, and the integrated superparamagnetic IONPs act as excellent contrast agents for T2-weighted magnetic resonance imaging. Especially, these Ta4C3-IONP-SPs composite nanosheets with high photothermal-conversion efficiency (η: 32.5%) has achieved complete tumor eradication without reoccurrence, verifying their highly efficient breast-tumor photo-ablation performance. Conclusion: This work not only significantly broadens the biomedical applications of MXene-based nanoplatforms (Ta4C3 MXene) by exploring their novel family members and further functionalization strategies (magnetic functionalization in this work), but also provides a novel and efficient theranostic nanoplatform for efficient breast-cancer theranostics.

Unique Fe3O4/polyaniline (PANI) composite with yolk-shell micro/nanostructure (FPys) has been successfully synthesized by a facile silica-assisted in-situ polymerization and subsequent etching strategy. The structural and compositional studies of the FPys composites are performed by employing X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The yolk-shell morphology of the products is confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. When evaluated as anode material for lithium-ion batteries, the as-prepared FPys electrodes deliver superior capacity, better cycling stability and rate capability than those of bare Fe3O4 micro/nanospheres and Fe3O4/PANI core-shell (FPcs) electrodes. Moreover, FPys also exhibits excellent electromagnetic wave absorption performance when comparing to the synthesized Fe3O4-based electromagnetic wave absorbers, in which strong reflection loss and extensive response bandwidth can be achieved simultaneously. The excellent bifunctional properties of FPys material are associated with the specially designed hierarchical micro/nanostructures. The current strategy that application directed structural design can be applied to the synthesis of other multifunctional materials.

Beyond the traditional focus on improvements in mechanical, electronic and absorption properties, controllability, actuation, and dynamic response of monoliths have received increasing attentions for practical applications. However, most of them could only realize simple response to constant conditions (e.g. a stationary magnetic field) while carrying out humdrum motions. By controlling distribution of metal organic framework obtained carbon-enriched Fe3O4 nanoparticles in self-assembly reduced graphene oxide (RGO) monoliths, we could achieve two distinctive RGO–Fe3O4 stirrers that could dynamically respond to the rapidly changing magnetic field while executing designed movements precisely: rotating with lying down posture or standing straight posture. These stirrers can not only be applied in environmental remediation (e.g. suction skimmer), but also be recycled as electrode active materials for supercapacitors after fulfilling their destiny, realizing transformation of trash to treasure, which will inspire other dynamically responsive monoliths for various applications.