Vibrating Sample Magnetometer Research Articles

Green synthesis, characterization and drug-loaded iron oxide nanoparticles derived from Nerium oleander flower extract as a nanocarrier for in vitro antibacterial efficacy

Application of drug conjugated iron oxide hematite (α-Fe2O3) nanoparticles are of tremendous interest in biomedicine nowadays. Meanwhile, green production of iron oxide nanoparticles is gaining favour due to its sustainability, ease of usage, and biocompatibility. Therefore, this work reports on the use of hexahydrate ferric chloride and nerium oleander flower extract to synthesize nanoscaled hematite (α-Fe2O3) iron oxide particles conjugated with various drugs for antibacterial agents. Diverse morphological, physicochemical, structural, optical, and magnetic characteristics have been characterized using FESEM, EDX, XRD, UV–vis, FTIR, Raman and vibrating sample magnetometer. The synthesis of the polyshaped iron oxide nanoparticles, with average sizes ranging from 47.2 ± 20 nm, was accomplished. Furthermore, temperature-dependent variations in magnetic behavior were observed during calcination. The XRD and Raman spectra revealed hematite (α-Fe2O3) type formation of iron oxide nanoparticles. Only calcinated IO-NPs at high temperatures (700 °C) demonstrated low coercivity and residual magnetism, which revealed weak ferromagnetic ordering; other calcinated samples, including nascent ones, showed incredibly weak ferromagnetic ordering. Besides, the effectiveness of drug-encapsulated iron oxide nanoparticles against bacteria in vitro was examined. It was interesting to observe that gentamycin-coated IO-NPs tended to be more susceptible to S. aureus than E. coli bacteria, but streptomycin-conjugated IO-NPs showed the reverse trend. However, as compared to the nascent sample and the high temperature (700 °C) calcinated sample, both antibiotic-loaded IO-NPs displayed better inhibitory abilities.

Synthesis of Cu3Fe4V6O24 Nanoparticles to Produce 1,2,3-Triazoles by Azide-Alkyne Cycloaddition Reactions.

This paper presents the fabrication of novel Cu3Fe4V6O24 nanoparticles (NPs) via a facile sol-gel method as efficient nanocatalysts (NCs) to produce azide-alkyne 1,3-dipolar cycloaddition compounds. The effect of the calcination time on the formation of NPs was investigated. The as-prepared NPs were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), electron-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET) analyses. Cu3Fe4V6O24 NCs were applied to azide-alkyne 1,3-dipolar cycloaddition reactions. The effect of the catalyst loading, temperature, and time of reaction was optimized to improve the efficiency of the NC function by the response surface methodology-central composite design (RSM-CCD) method. In optimal conditions, the yield of the reaction was 96%. In addition, the effect of different solvents on the yield of the reaction was investigated. Moreover, Cu3Fe4V6O24 NPs efficiently catalyze different 1,2,3-triazoles in excellent yields.

Enhancing the efficacy of cisplatin against breast cancer cells using carnosine‐functionalized magnetic nanoparticles

The majorities of chemotherapy drugs and drug‐delivery models have significant health concerns and cause undesirable side effects because they lack specificity and proper targeting systems and are too large. It is crucial to prioritize the rational design and synthesis of chemotherapeutics that specifically target their intended sites. This research work aims to create magnetic nanocarriers conjugated with L‐carnosine (CAR) as a cancer‐targeting peptide for the development of targeted anticancer drugs. These nanoparticles are designed to reduce toxicity, allow for sustained release, and increase the circulating time of cisplatin. The nanoparticles were made by coating them with silane and an aldehyde linker, which allowed them to be attached to L‐carnosine peptide. Cisplatin was then attached to the surface of the nanoparticles via chemical bonds. The prepared nanoparticles were characterized using vibrating sample magnetometer, dynamic light scattering, and scanning electron microscopy and FT‐IR spectrophotometry. In vitro studies demonstrated the cytotoxic and inhibitory effects of cisplatin nanoconjugates on breast cancer cells. Significantly, the nanoconjugates showed higher potency compared to free cisplatin. In continuous study, the optimization of synthesized compounds was performed using the DMol3 module in Materials Studio 2017. Energy calculations and molecular docking analysis using the HEX software revealed that the nanoconjugates showed stronger binding to the minor and major grooves of the DNA receptor. These interactions involved eight hydrogen bonds, exceeding those of other compounds.

Optimization of Vancomycin Antibiotic Removal from Synthetic and Real Wastewater Using UV/Fe3 O4 @Alg-ZnO Nanocomposite Photocatalysis: Response Surface Methodology Based on a Box-Behnken Design

Background: Vancomycin (VCM) is a critical antibiotic due to its high consumption and side effects, including increased bacterial resistance affecting treatment processes. This research investigated the efficiency of VCM antibiotic removal from an aqueous solution using a UV/Fe3 O4 @Alg-ZnO integrated process. Methods: Response surface methodology (RSM) and a Box-Behnken design were applied using Design-Expert software to optimize the number of samples and simultaneously understand the interactive effects between variables. X-ray diffraction (XRD), a vibrating-sample magnetometer (VSM), field effect scanning electron microscopy (FE-SEM), and Fourier transform infrared (FTIR) analyses were used to check the structural characteristics. The effects of initial catalyst concentration (0.1, 0.3, and 0.5 g/L), initial pollutant concentration (10, 30, and 50 mg/L), contact time (10, 30, and 50 minutes), and pH (3, 7, and 11) on VCM decomposition rate were investigated. Spectrophotometry, total organic carbon (TOC), and GC-MS analyses were used to check the efficiency of the process. Results: In this study, VCM and TOC removal efficiency was 92.64% and 85.38%, respectively, under optimal conditions. The reason for the reduction in the efficiency of the combined UV/Fe3 O4 @Alg-ZnO process in real raw sewage, after activated sludge (13%) and after activated sludge and stabilization ponds (24%), is the high COD, which causes the active radicals produced to be spent on other species instead of the VCM antibiotic. Conclusion: The current study showed that the UV/Fe3 O4 @Alg-ZnO process performs well in removing VCM and TOC. In real wastewater, this efficiency was significantly reduced.

Structural Elucidation and Evaluation of Magnetic and Dielectric Properties of Lu–La Co‐substituted M‐Type Hexagonal Ferrites Synthesized by Chemical Co‐precipitation Method

In this research, LuxLaySr1–yFe12–xO19, an M‐type strontium ferrite, is synthesized using the coprecipitation method with precursor chemicals. The samples undergo analysis for structure, morphology, and elemental composition through X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Magnetic and dielectric properties are determined using a vibrating sample magnetometer (VSM) and a dielectric property measurement instrument (LCR), respectively. The primary objective of this study is to enhance the dielectric performance of the samples through rare‐earth element doping. The XRD analysis reveals that the samples display a hexagonal single‐phase magnetoplumbite crystal structure. SEM micrographs illustrate a regular hexagonal structure of the grains. VSM analysis affirms LuxLaySr1–yFe12–xO19 as a hard magnetic material with a high coercivity. As the rare‐earth element content increases, the coercivity of the samples significantly decrease from 2065.3 to 910.3 Oe. Dielectric property analysis demonstrates that augmenting the rare‐earth element (Lu–La) content notably increases the relative dielectric constant of the samples. In the low‐frequency region, the relative dielectric constant ranges from 6.71 × 103 to 1.28 × 105, while in the high‐frequency region, it ranges from 3.09 × 103 to 2.03 × 104. Samples doped with rare‐earth elements exhibit a high dielectric constant and low coercivity, rendering them suitable for applications in electromagnetic shielding materials. This can help reduce interference from magnetic fields on internal components while blocking electromagnetic waves.

A novel and efficient boron-containing magnetic catalyst based on graphene oxide (GO-Fe3O4-BFn) for synthesis of pyrazole and pyranopyrazole derivatives

The creation of non-toxic acidic catalysts has benefited greatly from the immobilization of acidic materials on solid substrates. In the present work, a novel and capable magnetically Lewis acid catalyst based on graphene oxide (GO) was introduced for the synthesis of pyrazole derivatives. The new catalyst was prepared as a heterogeneous Lewis acid composite by immobilization on BF3 on GO-Fe3O4. The magnetic and recoverable catalyst was characterized by FT-IR (Fourier‑Transform Infrared Spectroscopy), FESEM (Field Emission Scanning Electron Microscopy), XRD (X‑Ray Diffraction), EDS (Energy-Dispersive X-Ray Spectroscopy), ICP (Inductively Coupled Plasma), VSM (Vibrating Sample Magnetometer) and TGA (Thermogravimetry Analysis) techniques. Catalytic activity of the GO-Fe3O4–BFn checked out in the synthesis of pyrazole (3a-3f) and 2,4-dihydropyrano[2,3-c] pyrazole (8a-8f) derivatives under mild conditions. Pyrazole and pyranopyrazol derivatives were synthesized in desirable yield in the presence of our new catalyst. High surface area, chemical and thermal stability, good selectivity, high reactivity with easily magnetically separation are some of advantageous of our catalyst. The catalyst can also be recycled for several times without reducing its catalytic efficiency. Furthermore, molecular docking studies were performed to predict the interaction mode of the synthesized compounds toward the EGFR kinase as a possible target.

Experimentally determining the thermophysical properties, heat transfer and friction factor Fe3O4-TiO2 magnetic hybrid nanofluids in a mini-heat sink under magnetic field: Proposing new correlations

The heat transfer and friction factor for the Fe3O4-TiO2/water nanofluids circulating in a mini-heat sink of comparable magnitude to personal computer or electronic gadgets with and without a magnetic field have been estimated experimentally. The Fe3O4-TiO2 nanomaterial was prepared using chemical coprecipitation and sol–gel technique. Synthesized Fe3O4-TiO2 nanoparticles were characterized by X-ray diffraction, and vibrating sample magnetometer. The water-based hybrid nanofluids were then used in a series of experiments for assessing heat transfer, and friction factor of a mini-heat sink assembly of five circular channels with 4 mm in diameter and 50 mm in length. The experiments were performed in the operating range: 238.66 < Re < 1873.36; 0 <ϕ < 2 %; and 0 < Gauss < 1000, respectively. Constant heat flux boundary condition was maintained at the bottom surface of the heat sink and an external magnetic field was provided with an electromagnet. Results indicate that, by using the Fe3O4-TiO2 hybrid nanofluid of 2 % vol. the Nusselt number, with no magnetic field, is enhanced over that of water by 38.16 %, and by 88.93 % when the magnetic field of 1000 gauss is applied. However, the hybrid nanofluid of 2 vol% imposed a penalty in increase in friction factor of 25.87 % without magnetic field, and 67.64 % when magnetic field of 1000 G is applied at a Reynolds number of 1873.33 over water data. The experimental data were used to develop generalized Nusselt number and friction factor correlations for a mini-heat sink subjected to an external magnetic field.

Characterization of a recombinant Aspergillus niger GZUF36 lipase immobilized by ionic liquid modification strategy

Enzyme immobilized on magnetic nanomaterials is a promising biocatalyst with efficient recovery under applied magnets. In this study, a recombinant extracellular lipase from Aspergillus niger GZUF36 (PEXANL1) expressed in Pichia pastoris GS115 was immobilized on ionic liquid-modified magnetic nano ferric oxide (Fe3O4@SiO2@ILs) via electrostatic and hydrophobic interaction. The morphology, structure, and properties of Fe3O4@SiO2@ILs and immobilized PEXANL1 were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, vibration sample magnetometer, and zeta potential analysis. Under optimized conditions, the immobilization efficiency and activity recovery of immobilized PEXANL1 were 52 ± 2% and 122 ± 2%, respectively. The enzymatic properties of immobilized PEXANL1 were also investigated. The results showed that immobilized PEXANL1 achieved the maximum activity at pH 5.0 and 45 °C, and the lipolytic activity of immobilized PEXANL1 was more than twice that of PEXANL1. Compared to PEXANL1, immobilized PEXANL1 exhibited enhanced tolerance to temperature, metal ions, surfactants, and organic solvents. The operation stability experiments revealed that immobilized PEXANL1 maintained 86 ± 3% of its activity after 6 reaction cycles. The enhanced catalytic performance in enzyme immobilization on Fe3O4@SiO2@ILs made nanobiocatalysts a compelling choice for bio-industrial applications. Furthermore, Fe3O4@SiO2@ILs could also benefit various industrial enzymes and their practical uses.Key points• Immobilized PEXANL1 was confirmed by SEM, FT-IR, and XRD.• The specific activity of immobilized PEXANL1 was more than twice that of PEXANL1.• Immobilized PEXANL1 had improved properties with good operational stability.Graphical abstract

Acoustic shock wave processing on amorphous carbon quantum dots – correlation between spectroscopic-morphological–magnetic and electrical conductivity properties

In this context, we report the acoustic shock wave processing on amorphous Carbon quantum dots (a-CQD) such that its degree of graphitization and magnetic properties are analyzed. Analytical techniques such as the Raman spectrometer, high resonation–transmission electron microscopy (HR-TEM) and vibrating sample magnetometer (VSM) are utilized to understand the structural, morphological and magnetic properties changes under shocked conditions. The Raman spectroscopic data reveal that the ID/IG ratio is slightly reduced under shocked conditions and the observed values are 0.78, 0.77 and 0.75 for the respective 0, 150 and 300 shocked conditions. The formation of ultra-short-range graphitic nanostructures is confirmed by HR-TEM results at the 300-shocked condition. The most convincing and supporting results for the enhancement of the degree of graphitization are found by the outcome of the magnetic properties such that the saturation magnetization (Ms) is found to be linearly reduced with respect to the number of shock pulses and the observed values are 0.869, 0.757 and 0.710 emu/g for the 0, 150 and 300 shocked conditions, respectively. The electrical resistance of the a-CQD is found to be linearly reduced with respect to the number of shock pulses due to the reduction of sp3 carbon networks. The formation of crystalline graphitic nanostructures in amorphous CQD is explained on the basis of the hot-spot nucleation mechanism. Based on the obtained Raman, HR-TEM and VSM results, during the shocked conditions, slight enhancement of the graphitization is observed; however, from the structural stability point of view, the Carbon dots have high shock resistance than that of the amorphous carbon nanoparticles, multi-wall carbon nanotubes, and reduced graphene oxide nanoparticles. Hence, the title quantum dots can be strongly considered for the applications of device fabrication.

Synthesis of Fe3O4@SiO2-creatine as a new nanosorbent for dispersive magnetic solid-phase microextraction of copper ions from water, food, and soil samples

For the first time, Fe3O4@SiO2-creatine (Fe3O4@SiO2-CRT) was synthesized and exploited as a nanosorbent in the dispersive magnetic solid phase microextraction (D-MSPμE) of copper from water, food, and agricultural soil samples. Flame atomic absorption spectrometry was employed for the quantification of concentration of Cu(II) ions subsequent to the elution process. Different techniques, including X-ray diffraction, fourier transform infrared, field emission scanning electron microscopy, and vibrating sample magnetometer, were utilized to characterize the synthesized nanosorbent. The factors influencing the efficiency of the extraction process were investigated and optimized. Under the optimal conditions (solution pH, 7.0; nanosorbent quantity, 20 mg; adsorption time, 7.0 min; desorption time, 2.0 min; and desorption agent, HNO3 0.5 mol L−1), the proposed method provided a wide linear range (5.0–125 ng mL−1) with a determination coefficient (R2) of 0.9991. The limit of detection, extraction recovery, and relative recoveries were obtained to be 1.50 ng mL−1, 98.1%, and 90.6–103%, respectively. The intra-day relative standard deviation percentages (n = 5) for different concentrations were in the range of 2.33–3.11%. The proposed method offers merits such as swiftness, high sensitivity, rendering it applicable to detect trace levels of copper (5.19–14.2 ng mL−1 or ng g−1) in water, food, and agricultural soil samples.

Vancomycin and nisin-modified magnetic Fe3O4@SiO2 nanostructures coated with chitosan to enhance antibacterial efficiency against methicillin resistant Staphylococcus aureus (MRSA) infection in a murine superficial wound model

BackgroundThe objective of this research was to prepare some Fe3O4@SiO2@Chitosan (CS) magnetic nanocomposites coupled with nisin, and vancomycin to evaluate their antibacterial efficacy under both in vitro and in vivo against the methicillin-resistant Staphylococcus. aureus (MRSA).MethodsIn this survey, the Fe3O4@SiO2 magnetic nanoparticles (MNPs) were constructed as a core and covered the surface of MNPs via crosslinking CS by glutaraldehyde as a shell, then functionalized with vancomycin and nisin to enhance the inhibitory effects of nanoparticles (NPs). X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), vibrating sample magnetometer (VSM), and dynamic light scattering (DLS) techniques were then used to describe the nanostructures.ResultsBased on the XRD, and FE-SEM findings, the average size of the modified magnetic nanomaterials were estimated to be around 22–35 nm, and 34–47 nm, respectively. The vancomycin was conjugated in three polymer-drug ratios; 1:1, 2:1 and 3:1, with the percentages of 45.52%, 35.68%, and 24.4%, respectively. The polymer/drug ratio of 1:1 exhibited the slowest release rate of vancomycin from the Fe3O4@SiO2@CS-VANCO nanocomposites during 24 h, which was selected to examine their antimicrobial effects under in vivo conditions. The nisin was grafted onto the nanocomposites at around 73.2–87.2%. All the compounds resulted in a marked reduction in the bacterial burden (P-value < 0.05).ConclusionThe vancomycin-functionalized nanocomposites exhibited to be more efficient in eradicating the bacterial cells both in vitro and in vivo. These findings introduce a novel bacteriocin–metallic nanocomposite that can suppress the normal bacterial function on demand for the treatment of MRSA skin infections.

Enhanced Magnetic Properties of Gd-Doped ZnO by Varying the Gd Concentration via Co-Sputtering Technique

This study reports on the effect of Gd concentrations on the properties of Gd-doped ZnO films. The films were prepared using co-sputtering method at room temperature. Characterization tools such as X-ray diffraction (XRD), atomic force microscopy (AFM), and vibrating sample magnetometer (VSM) were used to analyze the properties of the prepared films. XRD results observed that all the films are well crystalline and designated to the hexagonal wurtzite structure of ZnO with no secondary phases, which confirmed the successful of doping the Gd into ZnO. Topography analysis from AFM discovered the increase of Gd concentrations of Gd-doped ZnO films leads to the increase in grain size and rougher surface of the films. The magnetization of the films effectively depends on the Gd concentrations, which the diamagnetic behavior changed to ferromagnetic behavior upon Gd doping. A film with higher Gd doping concentration is more effective than lower Gd doping in terms of saturation magnetization (Ms), coercivity (Hc) and remanent magnetization (Mr). These findings revealed that optimizing the Gd concentration is very crucial in enhancing the magnetic properties of Gd-doped ZnO films.

Synthesis and characterization of a remarkable ternary boride: Mo2NiB2

In this communication, we report the synthesis of predominantly single phase Mo2NiB2 by pressureless reactive sintering. XRD analysis showed the samples were ≥95% pure. Both computational and experimental results showed the structure and space group to be orthorhombic and 71: Immm, respectively. Computational results showed Mo2NiB2 has superior mechanical properties as compared to ternary borides like MoAlB, WAlB and Cr2AlB2. As a representative example, the bulk modulus of Mo2NiB2 is 299.5 GPa, outperforming the range of 209.2–228.2 GPa observed in MAB phases. With experimental hardness of 12.0 ± 1.48 GPa and compressive strength of 2469.5 ± 84.6 MPa, Mo2NiB2 outperformed ternary borides like MoAlB, Fe2AlB2 and Mn2AlB2. Magnetic measurements by vibrating sample magnetometer showed Mo2NiB2 to be diamagnetic with minor ferromagnetism which was attributed to residual Ni in the samples.

Investigation of structural, optical, electrical and magnetic properties of magnetoelectric composite of NiFe2O4 and YMnO3

Magnetoelectric composites of Nickel Ferrite and Yttrium Manganite (xNiFe2O4 – (1-x) YMnO3, x = 0.25 and 0.50) were prepared using solid state reaction method. Their structural, optical, magnetic and electric behavior was studied by X-ray diffraction (XRD), UV–Vis spectroscopy, vibrating sample magnetometer (VSM), dielectric and polarization versus electric field (P-E) measurement at room temperature. Coexistence of the both ferrite and ferroelectric phases in the composites was confirmed by X-ray diffraction. Structural analysis had shown that lattice strain corresponding to nickel ferrite (NFO) phase was increased while for Yttrium Manganite (YMO) it was not much affected after formation of composites. The values of direct band gap for the composite came out to be larger than that for YMnO3 (1.43 eV) and smaller than that for NiFe2O4 (1.74 eV). Existence of ferromagnetic ordering in the composites was confirmed by VSM. Value of saturation magnetization was found to be highest in nickel ferrite (46 emu/g) and it was decreased with increase in concentration of ferroelectric phase in the composites. The sample with 75% YMO has shown highest dielectric constant (∼700) among all the four samples. P-E loops were not saturated and polarization current was found mainly due to conduction of charge carriers.

Magnetic nanoparticles loaded hydrochar for effective Cr(VI) removal from water: Batch and column studies

Chromium considered as most toxic trace metal and is essential to remove it from aqueous using influential adsorbents. Hydrochar prepared from mango peels biomass by thermal activation process was applied to produce activated hydrochr (ACH) which further prepared magnetic nano-composite activated hydrochar (Fe3O4-ACH) material as an effectual sorbent and tested for adsorption of Cr(VI) ions. SEM/EDS, BET, FTIR, VSM, and XRD instruments were utilized to evaluate the characteristics of produced Fe3O4-ACH. The obtained results revealed that the nanoparticle modification increased the surface area and improved the adsorption ability of ACH. A vibrating sample magnetometer was applied for magnetic properties in which the external magnetic field responded by saturation magnetization leading to quickly adsorbed metal ions from water. The factorial design studies were achieved to optimize the removal conditions of metal ions. Equilibrium data for isotherms (Langmuir isotherm) and kinetic mechanisms (pseudo second order) well fitted with the models. The obtained adsorption capacity for Langmuir isotherm was 174.7 mg/g under optimized conditions (dose 0.03 g, contact time 120 min, Cr(VI) solution 50 mg/L). Practical applications of real water samples were studied by fixed-bed column adsorption. The obtained results revealed that the synthesized Fe3O4-ACH was promising for Cr(VI) removal with adsorption capacity of 60.24 mg/g at optimized conditions; bed height (1.3 cm), Cr(VI) ions concentration (50 mg/L) and flow rate (12 mL/min). The experimental breakthrough curve results were compared in a fixed-bed column and were successfully fitted with kinetic models. The given results of distribution and selectivity coefficients proven that Fe3O4-ACH composite has a greater adsorption selectivity than adsorption of Cr(VI). Furthermore, computational molecular modeling was performed to evaluate the interaction types between Cr(VI), Fe3O4, and ACH. The Cr(VI) adsorption mainly carried hydrogen bonding, π–π, hydrophobic and electrostatic interactions. Desorption of chromium ions from Fe3O4-ACH composite adsorbent was more effective with 94.1% desorption efficiency. An approximate cost analysis of 3.15 USD/Kg in a week was assumed for activated hydrochar which was cheaper than the commercially available activated carbon which cost 20 USD/Kg. The obtained results indicated that the produced Fe3O4-ACH composite is a capable adsorbent to decontaminate Cr(VI) from real water samples.

A portable magnetic electrochemical sensor for highly efficient Pb(II) detection based on bimetal composites from Fe-on-Co-MOF

The practical, sensitive, and real-time detection of heavy metal ions is an essential and difficult problem. This study presents the design of a unique magnetic electrochemical detection system that can achieve real-time field detection. To enhance the electrochemical performance of the sensor, Fe2O3@C-800, Co/CoO@/C-600, and CoFe2O4@C-600 magnetic composites were synthesized using three MOFs precursors by the solvothermal method. And the morphology structure and electrochemical properties of as-prepared magnetic composites were researched by X-ray diffraction (XRD), Scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), specific surface area and porosity analyzer (BET) and differential pulse voltammetry (DPV). The results shown that these composites improve conductivity and stability while preserving the MOFs basic frame structure. Compared with the monometallic MOFs-derived composites, the synergistic effect of the bimetallic composite CoFe2O4@C-600 can significantly enhance the electrochemical performance of the sensor. The linear range for the detection of lead ions was 0.001–60 μM, and the detection limit was 0.0043 μM with a sensitivity of 22.22 μA μM·cm−2 by differential pulse voltammetry. The sensor has good selectivity, stability, reproducibility and can be used for actual sample testing.

Preparation of congo red functionalized core@double-shell magnetic Fe3O4@SiO2@MBH microsphere for removal of methylene blue and Cu(II) from aqueous solution

A novel core@double-shell magnetic microsphere Fe3O4@SiO2@7MgO·2B2O3·7 H2O (Fe3O4@SiO2@MBH) for the efficient adsorption of congo red (CR) was successfully synthesized. Subsequently, a CR-functionalized sample (Fe3O4@SiO2@MBH-CR) was prepared for methylene blue (MB) and Cu(II) removal from wastewater. Through techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, etc., the chemical composition, physical characteristics, and magnetic properties of ferromagnetic composite particles were identified. Many important factors, including pH, adsorption period, and elution characteristics, were evaluated and then adjusted accordingly. The highest concentration of adsorption for CR was approximately 332.53 mg g−1 under ideal conditions, indicating a higher adsorption capacity. Fe3O4@SiO2@MBH-CR exhibited significantly higher adsorption capacities compared to other known adsorbents, removing 408.51 mg g−1 for MB and 63.26 mg g−1 for Cu(II) through electrostatic attraction. Consequently, the Freundlich isotherm framework and the pseudo-second-order kinetic framework explained the adsorption kinetics and isotherm data, respectively. It is essential to remember that an external magnet facilitated the easy removal of adsorbents from a water-based solution. The potential adsorption mechanism was briefly explored, and our findings suggest that the new adsorbent Fe3O4@SiO2@MBH is a promising candidate for enhancing dye and Cu(II) adsorption capabilities from aqueous solutions.

Probing temperature-dependent magnetism in cobalt and zinc ferrites: A study through bulk and atomic-level magnetic measurements for spintronics

Spinel ferrites (MFe2O4) are integral to various industries, particularly spintronics, which utilizes the intrinsic spin of electrons as well as the electronic charge to develop devices that dictate spin-based transport, advancing new memory, logic applications, and improving magnetic storage technologies. These materials are valued for their exceptional optical, magnetic and electrical properties, and their easily tunable shape and size. This flexibility of spinel ferrites and their connection to the material’s magnetic behavior can be investigated by studying a range of spinel ferrite structures. In this study, the magnetic behaviors of cobalt ferrite (CFO) and zinc ferrite (ZFO) nanoparticles were examined using a vibrating sample magnetometer (VSM, bulk magnetometry) and X-ray Magnetic Circular Dichroism (XMCD, atomic magnetometry). The Rietveld refinement of XRD data supported single phase spinel structure, while X-ray Absorption Spectroscopy (XAS), particularly through the Co L-edge XANES analysis, detected both Co2+ and Co3+ ions in CFO, suggesting significant ferromagnetic behavior due to octahedral site occupation. In contrast, ZFO exhibited antiferromagnetic character, with Zn2+ ions in tetrahedral sites, and canted antiferromagnetism manifesting as a hysteresis loop below 300 K, potentially related to lattice distortions or strain. At the atomic scale, XMCD analysis, along with sum rules, estimated the average magnetic moments for cobalt and zinc ferrites to be 3.045 ± 0.1 (1.448 ± 0.1) and 0.657 ± 0.1 (2.12 ± 0.1) μB at temperatures of 300 K (90 K), respectively. However, VSM-based bulk measurements indicated magnetic moments of 2.566 (2.288) and 0.281 × 10−3 (0.6503 × 10−3) μB for CFO and ZFO, respectively, at the same temperatures. The observed variation between bulk and atomic-scale magnetic moments points to complex interstitial interactions within the spinel ferrite’s sublattices. This discrepancy between the atomic-scale and bulk magnetic moments suggests intricate interstitial interactions within the spinel ferrite’s sublattices. These insights into the structural and magnetic intricacies of spinel ferrite nanoparticles enhance our understanding, facilitating the design of cutting-edge spintronic devices.

Preparation and Peculiar Magnetic Properties at Low Temperatures of La1.85Sr0.15CuO4 Nanofibers.

Herein, the preparation process, morphology, structure, and magnetic properties of La1.85Sr0.15CuO4 (LSCO) cobweb-like nanofibers are reported. LSCO nanofibers with a regular grain size distribution are successfully prepared via electrospinning, followed by calcination. We conducted morphology analysis and elemental distribution using electron microscopy and energy-dispersive X-ray spectroscopy (EDS), respectively. Additionally, magnetic property testing was performed using a vibrating sample magnetometer (VSM) to confirm the superconducting properties of the samples. Interestingly, our samples exhibited a superconducting transition temperature, Tc, of 25.21 K, which showed some disparity compared to similar works. Furthermore, we observed a ferromagnetic response at low temperatures in the superconducting nanofibers. We attribute these phenomena to the effects generated by surface states of nanoscale superconducting materials.

Employing the Microemulsion Synthesis Technique to Investigate the Structural and Magnetic Properties of Multicomponent Ferrite Nanoparticles

AbstractCoFe2O4, ZnFe2O4, NiFe2O4, Co0.5Ni0.5Fe2O4, Ni0.5Zn0.5Fe2O4, and Co0.5Zn0.5Fe2O4 are among the multicomponent ferrite nanoparticles that are created using the reverse microemulsion technique and a mixed surfactant. These nanoparticles are thoroughly characterized using techniques such as vibrating sample magnetometer (VSM), energy dispersive X‐ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT‐IR), and X‐ray diffraction (XRD). All the nanoparticles display a cubic spinel crystal structure, according to the X‐ray investigation. As the concentration of zinc increases, there is a noticeable rise in the lattice constant because the size of Zn+2 is more than Co+2. This study also investigates the relationship between the magnetic characteristics of nanocrystals and their matching size, composition, and features.