Vibrating Sample Magnetometer Research Articles

Magnetic dispersive solid-phase extraction of clarithromycin and azithromycin by Fe3O4@ionic salt g-C3N4 adsorbent and HPLC-UV

In this study, Fe3O4@ionic salt g-C3N4 was synthesized as a new adsorbent for magnetic dispersive solid phase extraction (MDSPE) of two antibiotics (clarithromycin and azithromycin) in biological samples followed by HPLC-UV. The new nanocomposite was characterized by Fourier-transform infrared (FT-IR), field emission-scanning electronic microscope (FE-SEM), transmission electron microscope (TEM), nitrogen adsorption–desorption analysis, X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). Box-Behnken design (BBD) and response surface methodology (RSM) were used for the optimization and design of experiments. The method had a suitable linear range (1–300 µg/L), a high coefficient of determination (R2; 0.9988 and 0.9993), and a low detection limit (0.33 and 0.42 µg/L) for clarithromycin and azithromycin, respectively. The applicability of the method was evaluated by estimating the recovery of analytes from urine and blood serum samples. Recovery of more than 90.0 % and RSDs of less than 5.2 % show the acceptable accuracy and precision of the proposed method.

Exploring the effective adsorption of polystyrene microplastics from aqueous solution with magnetically separable nickel/reduced graphene oxide (Ni/rGO) nanocomposite.

Microplastics (MPs) are a potential threat to both humans and aquatic environment as they serve as carriers of various contaminants necessitating the development of reliable, efficient, and ecofriendly techniques to remove MPs from water. In this study, reduced graphene oxide (rGO) magnetized using nickel nanoparticles was utilized as a potent adsorbent for the effective removal of microplastics from water. The synthesized nickel/reduced graphene oxide (Ni/rGO) nanocomposite was characterized by X-ray diffraction (XRD), Raman spectra, vibrating sample magnetometer (VSM), scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX), thermogravimetric analysis, and Brunauer-Emmett Teller (BET) analysis. Magnetic Ni/rGO nanocomposite exhibited significant adsorption capability for polystyrene (PS) microspheres allowing the formation of PS-Ni/rGO complex which can be easily separated out using a magnet. The SEM images of PS-Ni/rGO complex confirmed the adsorption of PS microspheres onto the nano adsorbent due to hydrophobic interaction. The adsorbent demonstrated a maximum adsorption capacity of 1250mg/g. The analysis of isotherm and kinetic models demonstrated that the adsorption mechanism conformed to the Langmuir isotherm and followed pseudo second order kinetics. This study paves a new pathway for the application of magnetically modified reduced graphene oxide for the expedient removal of microplastics from water with the ease of separation using a magnet. The adsorbent was recycled and reused for three times.

Enhanced hydrogen storage performance of zinc and magnesium cobaltite nanocomposites

Renewable and sustainable energies are vital for the near future. Hydrogen, as a clean energy carrier, is a potential candidate for supplying energy in the foreseeable future. Nowadays, hydrogen storage technology has become a significant issue in the energy sector. In this study, ZnCo2O4/ZnO and MgCo2O4/MgO nanocomposites have been synthesized using the sol-gel method with stearic acid as a complexing agent. Different analyses were studied to examine the crystal structure, morphology, and physical properties of the as-prepared samples, including X-ray diffraction (XRD), Fourier transforms infrared (FT-IR), field emission scanning electron microscopy (FESEM), diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM). Various methods have been utilized for hydrogen storage technology. In a pioneering approach, the electrochemical hydrogen storage of samples was compared by the chronopotentiometry technique in KOH (4 M) electrolyte solution. The results reveal that ZnCo2O4/ZnO and MgCo2O4/MgO nanocomposites exhibit excellent discharge capacities of 4240 and 3529 mAh/g, respectively, after 11 cycles.

Synthesis and characterization of magnetic nanoparticles decorated by carbon layers acting as defenders against bacterial infectious agents

High stability magnetic nanocomposites wrapped by carbon layers were efficiently synthesized using electrical arc powered by single arc unit. This is sufficient to ionize the nickel, and carbon electrodes immersed in distilled water through applying strong electric field between carbon rotatory cathode and nickel anode. Nickle decorated by carbon (Ni@C) nanocomposite was fully characterized by transmission electron microscope (TEM), X-ray Diffraction (XRD), Vibrating-sample magnetometer (VSM), UV/Visible Spectrophotometer (UV), Fourier-transform infrared spectroscopy (FTIR), Particle size analyzer (PZ), Zeta potential, and X-ray photoelectron spectroscopy (XPS). Ni particle was spherical with average size equals to 17 nm wrapped by carbon where its energy band gap values were 2.84 for C, and 3.36 eV for Ni. The estimated phase percentage of nickel was 64.8 % which is higher than the percentage of carbon layers that's donating the sample the observed high stability of zeta potential was found to be 26.4 mV. The saturation magnetization (Ms) and coercivity (Hc) examined were 10.624 emu/g and 80.648 G, respectively. The antibacterial effect of the synthesized nanocomposites was tested against standard ATCC (American Type Colony Collection) strains namely Pseudomonas aeruginosa 27853, Proteus mirabilis 35659, Proteus vurgalis 13315, Klebsiella pneumoniae 13883, and Staphylococcus epidermidis 12228. Proteus vurgalis 13315 was the most resistant strain which wasn't completely eradicated after 24 h incubation with the prepared nanoparticles. Further assessments through confocal microscope and reactive oxygen species (ROS) generation percentage were done to predict the possible antibacterial mechanism of the synthesized nanocomposite. Ultimately, the combined influence of nickel ions and carbon in the prepared Ni@C nanocomposite results in the suppression of bacterial respiration and the induction of oxidative stress, ultimately leading to bacterial cell death.

Adsorption and catalytic degradation of tetracycline hydrochloride by HCNTs /MnFe2O4

Developing efficient, stable and selective materials is essential for removing antibiotics from aquatic systems. In this study, one composite is prepared via loading of magnetic MnFe2O4 onto hydroxylated multi-walled carbon nanotubes (HCNTs) through co-precipitation, named as HCNTs/MnFe2O4. The characterization of materials was performed using various methods, such as Vibrating Sample Magnetometer (VSM), Electron Paramagnetic Resonance (EPR), etc. There are larger surface and good magnetic property, which are useful to bind adsorbate and easy separation from mixtures. The as-synthesized composite exhibited excellent adsorption capacity and ability to activate potassium persulfate (KPS) for the efficient removal of Tetracycline hydrochloride (TC) from solution. The results showed that the adsorption capacity of HCNTs/MnFe2O4 towards TC was 341 mg·g–1 at 303 K. The kinetic process can be elucidated using pseudo-second-order kinetic model while the adsorption equilibrium can be fitted by Freundlich model. The mechanism of adsorption may include electrostatic attraction, complexation, π-π stacking, etc. To initiate Fenton-like heterogeneous catalytic degradation, KPS was added to the adsorption system to degrade and remove TC from solution. The experimental results showed that HCNTs/MnFe2O4 as a catalyst could achieve up to 89 % degradation of TC in the range of pH=3–8 due to its ability to generate active species such as ‧OH, SO4‧-, ‧O2- and 1O2 as confirmed from radical capturing experiments and EPR analysis. The removal efficiency after three adsorption regeneration or degradation cycles could reach up to 56 %, confirming its good reusability properties. There are good prospects of HCNTs/MnFe2O4 for the practical removal of antibiotics from aqueous solutions.

Eco-Friendly biogenic synthesis, characterization of Au/Fe3O4 magnetic nanoparticles and its catalytic activity towards degradation of Rhodamine-B

Eco-Friendly biogenic synthesis of gold and iron oxide (Au/Fe3O4) Magnetic nanoparticles (MNPs) using Lepidagathis cristata (LC) leaf extract act as capping and reducing agent. The prepared MNPs was characterized by different analytical techniques such as UV-Vis, FT-IR, XRD, TEM, VSM and BET adsorption-desorption methods. The XRD revealed the formation of LC/Au/Fe3O4 MNPs with crystallite size of about~30 nm. The synthesized LC/Au/Fe3O4 MNPs were found to be ferromagnetic nature, which was confirmed by vibrating sample magnetometer (VSM) at room temperature. Besides, the prepared composite exhibits high specific surface area of 23.6 m2g-1. As well as, the LC/Au/Fe3O4 MNPs showed a good catalytic nature for the degradation of Rhodamine-B (Rh-B) in the presence of Sodium borohydride (NaBH4) in aqueous solution.

Synthesis, magnetic properties, biotoxicity and potential mechanism of modified nano zero-valent iron for decolorization of dye wastewater

ABSTRACT SiO2-coated nano zero-valent iron (nZVI) has emerged as a fine material for the treatment of dye wastewater due to its large specific surface area, high surface activity, and strong reducibility. However, the magnetic properties based on which SiO2-coated nZVI (SiO2-nZVI) could effectively separate and recover from treated wastewater, and the biotoxicity analysis of degradation products of the dye wastewater treated by SiO2-nZVI remain unclear. In this study, SiO2-nZVI was synthesized using a modified one-step synthesis method. The SiO2-nZVI nanoparticles were characterized using Transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Fully automatic specific surface and porosity analyzer, Vibrating sample magnetometer, and Zeta potential analyzer. The removal rate of methyl orange (MO) by SiO2-nZVI composite reached 98.35% when the degradation performance of SiO2-nZVI treating MO was optimized. Since SiO2-nZVI analysed by magnetic hysteresis loops had large saturation magnetization and strong magnetic properties, SiO2-nZVI exhibited excellent ferromagnetic behaviour. The analysis of the degradation products showed that the MO treated by SiO2-nZVI was converted into a series of intermediates, resulting in reducing the toxicity of MO. The potential mechanism of MO degradated by SiO2-nZVI was speculated through degradation process and degradation kinetics analysis. Overall, the SiO2-nZVI composite may be regarded as a promising catalyst for decolorization of dye wastewater.

Characterization and optimization of ultrasound assisted oxidative desulfurization of a model fuel using a novel magnetic deep eutectic solvent

ABSTRACT In various studies, researchers have utilised different solvents to extract sulfur compounds from the fuels. This paper introduces a novel magnetic deep eutectic solvent employed in the ultrasound-assisted oxidative desulfurisation of dibenzothiophene within a model fuel. The solvent, synthesised at 85°C by combining choline chloride, p-toluene sulfonic acid, and FeCl₃, underwent characterisation through Fourier transform-infrared, Vibrating-sample magnetometer, and Raman spectrometry. Exploration of the key parameters, including oxidant to model fuel volumetric fraction percentage (0.2–0.3), Iron (III) chloride to choline chloride mole fraction (0.1–0.3), and Magnetic deep eutectic solvent to model fuel volumetric fraction (0.2–0.3), was conducted to assess their impact on dibenzothiophene conversion rates. Employing response surface methodology based on central composite experimental design, optimal operational parameters for the ultrasound-assisted oxidative desulfurisation process were identified, resulting in a sulfur removal rate of 98.7%. The findings highlight the solvent sustained efficiency even at higher dibenzothiophene concentrations. Additionally, the solvent paramagnetic properties facilitated an expedited separation from the fuel, leading to the significantly reduced process times.

Effect of the surface coating of carbonyl iron particles on the dispersion stability of magnetorheological fluid

The dispersion stability of carbonyl iron particle (CIP)-based magnetorheological fluid (MRF) is improved by CIP, which particle is etched with hydrochloric acid (HCl) to form porous structure with many hydroxyl groups and subsequently coated with silane coupling agents that have varying chain lengths. The microstructures, coating effect and magnetism of the CIPs were examined using the Scanning Electron Microscopy, Automatic Surface and Porosity Analyzer (BET), Fourier-Transform Infrared Spectroscopy, Thermogravimetric Analysis and Vibrating Sample Magnetometer. Furthermore, the rheological properties and dispersion stability of the MRFs were assessed using a Rotating Rheometer and Turbiscan-lab. The results revealed that the nanoporous structure appeared on the CIPs and the specific surface area increased remarkably after being etched by hydrochloric acid. Additionally, as the chain length of the silane coupling agent increases, the coated mass on the particles increases, the the density and the saturation magnetization of particles decreased, and the coated particles with different shell thicknesses were obtained; without a magnetic field, the viscosity of MRF prepared by coated particles increase slightly, due to the enhancement of special three-dimensional network structure; under a magnetic field, the viscosity of the MRF decreased distinctly; the sedimentation rate of MRF decreased from 58 to 3.5% after 100 days of sedimentation, and the migration distances of the MRFs were 22.4, 3.7, 2.4, and 0 mm, with particle sedimentation rates of 0.149, 0.019, 0.017, and 0 mm/h, respectively. The MRF with high dispersion stability was obtained, and the etching of CIP by HCl and the proper chain length of the coating of silane coupling agent were proved effective manners to improve the dispersion stability of MRF.

Composites of Zn-Co spinel ferrites and PANI: Structural, magnetic, microwave absorption characterization in 18–40 GHz

The present research work deals with the fabrication of composites containing spinel ferrites and polyaniline as high-performance microwave absorbers. The composites were prepared by the inter-mixing of Zn-Co spinel ferrites and PANI polymer in a 4:1 M ratio using the mechanical blending technique. The sol–gel citrate route was employed to synthesize Zn-Co spinel ferrites, while the oxidative polymerization method was used to synthesize PANI. The structural, morphological, magnetic, and microwave absorption properties of the composite samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM), and vector network analyzer (VNA), respectively. The X-ray diffraction patterns indicated the crystalline nature of spinel ferrites and the amorphous nature of PANI. The magnetic properties revealed that saturation magnetization (Ms) increased significantly with the addition of spinel ferrites into PANI owing to its magnetic nature. The microwave absorption results showed that the minimum reflection loss (RL) reached up to −26.63 dB at 20.72 GHz with the effective bandwidth of 5.95 GHz in the K-band and −39.16 dB at 35.68 GHz with the effective bandwidth of 8.1 GHz in the Ka-band for composition NZP. This study indicated that the prepared SF/PANI composites can be proposed as a promising absorbent in the K-band and Ka-band.

Modification of new magnetic nanocomposites Bi2WO6/CuFe2O4 and its excellent catalytic reduction for toxic nitroaromatic compounds and chromium (VI)

New magnetic Bi2WO6/CuFe2O4 nanocomposites were synthesized using hydrothermal method. The specific features of Bi2WO6/CuFe2O4 nanocomposites were studied using various analytical techniques such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and N2 adsorption desorption analyses, Brunauer-Emmett-Teller (BET). The BET analysis demonstrates that embedded CuFe2O4 nanoparticles in Bi2WO6 structure have increased the pore diameters and surface area for better adsorption of NaBH4 and catalytic performance. The VSM analysis confirms the magnetic behavior of nanocomposite which showed that Bi2WO6/CuFe2O4 could be separated and recoverd easily by an external magnet after catalytic reactions. The catalytic performance of nanocomposites was investigated for the reduction of nitroaromatic compounds including 4-nitroaniline (4-NA), 4-nitrophenol (4-NP), 2-nitroaniline (2-NA) and 2-nitrophenol (2-NP) and chromium (VI) in aqueous solution. The results show the nanocomposites have excellent ability to reduces Cr(VI) to Cr(III) and nitroaromatic compounds to the corresponding amines in green water solution at room temperature. The best performance observed for the 100% conversion of 4-nitrophenol reduction belongs to Bi2WO6/CuFe2O4 20%, which completes in 6 min, and its rate constant is about 0.67 min−1. In addition, the Bi2WO6/CuFe2O4 nanocomposite can be appropriately recycled and reused several times without changing its structure and activity, which is essential for practical applications.

Comparative study between oxide/soft ferrite, oxide/hard ferrite, and soft/hard ferrite nanocomposites: structural, electrical, and magnetic properties

Three binary nanocomposites (NCs): (0.5NiO/0.5Ni0.5Zn0.5Fe2O4), (0.5NiO/0.5BaFe12O19), and (0.5Ni0.5Zn0.5Fe2O4/0.5BaFe12O19) were prepared using the co-precipitation method followed by the wet ball-milling technique. X-ray diffraction analysis showed the production of NiO and Ni0.5Zn0.5Fe2O4 single phases, while the α-Fe2O3 secondary phase appeared in the BaFe12O19 and the 0.5Ni0.5Zn0.5Fe2O4/0.5BaFe12O19 nanocomposite. The transmission electron microscopy investigation and the selected area electron diffraction demonstrated the presence of the nanocomposites’ constituent phases. x-ray photoelectron spectroscopy identified the oxidation states found in the prepared samples (Ba2+, Ni2+, Ni3+, Zn2+, Fe3+, and O2−). The bandgap values (Eg) of the nanocomposites are in the range between 2.79 and 3.66 eV, which indicates their semiconductor nature. The DC conductivity experiment confirmed the semiconducting nature of all samples, and the activation energies ( EaH ) and ( EaL ) at high and low-temperature regions, respectively, were calculated from the Arrhenius equation. According to the vibrating sample magnetometer, the NCs exhibited ferromagnetic (FM) as showed by the M-H loops. In the oxide/soft ferrite NC, the dM/dH curve indicated strong exchange coupling interactions, while the hard and the soft magnetic phases in the oxide/hard ferrite and the soft/hard ferrite NCs were weakly exchanged coupled. Significant uses had been found for each of the three nanocomposites according to their constituent phases and properties.

Unlocking antimicrobial activity of gamma irradiated iron-zinc nanoparticles

Waterborne and foodborne diseases are generated by spoilage microorganisms with severe consequences for public health. Therefore, it is imperative to develop a way forward for their growth inhibition. In this contribution, iron-zinc (Fe-Zn) nanoparticles (NPs) were induced by gamma radiolysis as potential antimicrobial agents. X-ray diffraction (XRD) showed the formation of cubic iron oxide and hexagonal zinc oxide as mixed phases in accordance with microscopic observations. Energy dispersive X-ray spectroscopy (EDS) depicted the presence of Fe, Zn, and O within the sample. Photoluminescence (PL) revealed the existence of oxygen vacancies, which were consistent with the ferromagnetic behavior of the vibrating sample magnetometer (VSM). Besides, the antimicrobial activity was more pronounced against Dekkera bruxellensis.

Radical dendrimer: bis-indolyl polyurethane dendrimers containing TEMPO radicals for inhibition of cancer cell growth

Blocked isocyanate-terminated polyurethane dendrimers of first-generation (G1) to third-generation (G3) build-up with bis-indolyl units were subjected to urethane interchange reaction with 4-hydroxy-2, 2, 6, 6-tetramethylpiperidin-1-yloxyl (4-hydroxy TEMPO). The resulting free radical functionalized dendrimers were thoroughly characterized. The electron paramagnetic resonance (EPR)and vibrating sample magnetometer (VSM) results confirmed that these radical dendrimers are stable and paramagnetic. The cytotoxic effect of G1–G3 TEMPO-dendrimers was studied comprehensively across various cancer cell lines, encompassing human breast cancer (MCF-7 and MDA-MB-231), cervical cancer (SiHa), and lung cancer (A549 and NCI-H460), as well as normal lung epithelial cells (L132). It was observed that these TEMPO-dendrimers exerted cytotoxic effects in all cancer cell lines while demonstrating minimal impact on lung epithelial cells. Notably, MDA-MB-231 displayed heightened susceptibility to the TEMPO-dendrimers. Cell cycle analysis and morphological studies revealed that the TEMPO-dendrimers induced G1 phase cell cycle arrest and cell death specifically in breast cancer cells. Further investigations unveiled that these TEMPO-dendrimers triggered oxidative stress-mediated cell death specifically in breast cancer cells. All these findings suggest that the TEMPO radical dendrimers reported in this work exhibited cytotoxic effects in cancer cells by stimulating oxidative stress.

Synthesis and multifunctional characterizations of Gd2 O3 and Sm2 O3 modified ZnO nanoparticles

In the present communication multifunctional characterizations suitable for spintronics and memory storage devices are described. Double doped (Gd3+, Sm3+) ZnO nanoparticles are prepared from Sol-Gel method using poly vinyl alcohol (PVA) as chelating agent. The as prepared powders are annealed at 500 °C–1000 °C with a step size of 100 °C. The genesis of single phase hexagonal wurtzite structure, morphological and topographical changes, optical, magnetic and mechanical properties were studied with XRD (X-ray diffraction), SEM (scanning electron microscopy), TEM (transmission electron microscopy), EDS (energy dispersive spectroscopy), UV- DRS (ultraviolet diffuse reflective spectroscopy), PL (photoluminescence), VSM (vibrating sample magnetometer) and pin on disc tribometer. XRD study untangled the crystallite size and found to be in the range23-50nm. Polycrystalline nanoparticles of spherical geometry with induced porosity is observed from SEM study. The particle size associated with the samples annealed at 500 °C and 900 °C is 24 nm and 27 nm respectively from TEM study. Analyzed the proximity of functional groups, molecular vibrations in the range of 400-4000 cm−1 employing FTIR (Fourier transform infrared spectroscopy). EDS results revealed the stoichiometry of the produced samples. The pronounced optoelectronic applications of Zn1-x Gdx Smx O (ZGS) can be attributed to the large band gap (3.50–3.02 eV) associated with the materials with rise in annealing temperature. The room temperature ferromagnetism was evidenced with double doped ZnO nanomaterials. The wear coefficient, and friction coefficient were evaluated using pin-on-disc tribometer. The utility of materials as solid state lubricants was confiscated from the range of frictional coefficient values (0.067–0.893).

Characterization and antibacterial studies of Sn doped CuO nanocomposite using centratherum punctatum leaf extract

In order to synthesize CuO, SnO2, and Sn doped CuO nanocomposites, accessible and non-toxic materials, specifically leaf extract from Centratherum punctatum, were used in this work to apply the concepts and practices of green chemistry. These methods are both economical and environmentally friendly. A comprehensive range of characterisation techniques, including as FTIR, X-ray diffraction, and UV-vis spectroscopy, were also used to confirm the structures of all the produced nanomaterials. Instead, FESEM and EDAX were used to analyze the morphologies and elemental composition of recently produced nanomaterials. A decline in the optical band gap values was indicated by the red shift observed in the UV-vis study following tin doping. A sample's presence of different functional groups is confirmed by FT-IR analysis. For CuO NPs, SnO2, and Sn doped CuO NCs, the XRD results yielded crystallite sizes of 6 nm, 21 nm, and 29 nm, respectively, for the produced particles. The ferromagnetic, diamagnetic, and super paramagnetic characteristics of the produced samples at room temperature were validated by vibrating sample magnetometer experiments. Cyclic voltammetry is used to examine the nanoparticles' electrochemical analysis. Using Sn doped CuO nanocomposite material, it shows a high specific capacitance value of about ~187 Fg-1 at a current density of 10 mV/s. It was found from the electrochemical studies that the produced nanomaterials are suitable for capacitive behaviour. After all, the presence of inhibition zones surrounding each well led us to the conclusion that the nanoparticles exhibited antibacterial activity against the pathogenic strains of Staphylococcus aureus and Escherichia coli.

Phase Formation and Magnetic Properties of (Y1−xSmx)Co5 Melt-Spun Ribbons

Using X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM), the effects of Sm substitution, wheel speed, and annealing temperature on the phase formation and magnetic properties of (Y1−xSmx)Co5 (x = 0.2, 0.3, 0.4, 0.5) melt-spun ribbons were investigated. The results indicate the following: (1) With the increase in Sm substitution, it was found that (Y1−xSmx)Co5 ribbons are entirely composed of the (Y-Sm)Co5 phase with a CaCu5-type structure. Additionally, the coercivity gradually increases, while the remanence and saturation magnetization gradually decrease. (2) As the wheel speed increases, the (Y1−xSmx)Co5 ribbons exhibit an increasing proportion of (Y-Sm)Co5 phase until reaching a speed of 40 m/s, where they are entirely composed of the (Y-Sm)Co5 phase. Magnetic measurements show that the coercivity (Hcj) and remanence (Br) of (Y0.5Sm0.5)Co5 ribbons increase gradually with increasing wheel speed, while saturation magnetization decreases. The variation in magnetic properties is mainly attributed to the formation of nucleation centers for reversed magnetic domain (2:7 and 2:17 phases); (3) (Y0.5Sm0.5)Co5 ribbons are composed of the (Y-Sm)Co5 phase and a small amount of the Sm2Co7 phase after annealing at 550 °C, 600 °C, and 650 °C. Temperature elevation promotes crystallization of the amorphous phase, resulting in a gradual decrease in coercivity, while the remanence and saturation magnetization exhibit an overall increasing trend. Through continuous optimization of the process, favorable magnetic properties were achieved under the conditions of a 0.5 Sm substitution level, a wheel speed of 40 m/s, and an annealing temperature of 550 °C, with a coercivity of 7.98 kOe, remanence of 444 kA/m, and saturation magnetization of 508 kA/m.

Effect of Cr3+ substitution on the structural and magnetic properties of Co-Cu-Zn nano ferrites

Nano-ferrite materials with chemical compositions Co0.5Cu0.45Zn0.05Fe2-xCrxO4 (x = 0.0, 0.05, 0.1, 0.15, 0.2, and 0.25) (Co-Cu-Zn) nano ferrite materials were synthesized through the sol–gel auto-combustion method, and analytical characterizations of their structural and magnetic properties were conducted. Utilizing the Debye-Scherrer equation, the average crystallite sizes of the synthesized samples were determined to range from 37.25 nm to 53.56 nm, and X-ray diffraction (XRD) examination verified the synthesis of a single-phase cubic spinel structure. Microstructural and morphological properties were investigated using Field-Emission Scanning Electron Microscopy (FESEM) scanning, revealing grains in the nano-scale range. Two distinct peaks were observed at approximately 595 cm−1 and 392 cm−1, providing information about the functional groups of the samples’ chemical characteristics according to Fourier transform infrared analysis (FTIR). Room temperature vibrating sample magnetometer (VSM) analysis provided magnetic information on the materials, presenting various values of magnetic parameters. The samples’ hysteresis curves showed that the saturation magnetization and coercivity almost decreased when the dopant concentration in the host Co-Cu-Zn is increased.

Characteristics of the incorporation of Yb defect states in CuO:ZnO nanocomposite

Exploring magnetic order in nonferromagnetic substances, such as CuO:ZnO, becomes especially attractive when introducing defect states through nonmagnetic ion doping. In this study, we delved into the impact of Yb doping on the structural, morphological, optical, and magnetic properties of CuO:ZnO. The Yb doped CuO:ZnO was prepared with different Yb concentrations (x = 0.00–20 %) via the temperature-assisted co-precipitation method. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, and vibrating sample magnetometer (VSM) were used to investigate the structural, morphological, optical, and magnetic properties of Yb doped CuO:ZnO nanocomposites.The incorporation of Yb in CuO:ZnO nanocomposites leads to a notable shift of the characteristic XRD peaks of CuO and ZnO to lower angles, accompanied by an increase in the lattice parameters. UV–visible absorption spectroscopy shows an overall decrease in the optical band gap energy of ZnO as the Yb defect level increases. FE-SEM studies revealed the transformation of spherical structures into agglomerated non-spherical structures upon the introduction of Yb ions into CuO:ZnO nanocomposites. According to XPS data, the predominant valences of Yb-doped CuO:ZnO nanocomposites are Zn2+, Cu2+, and Yb3+. One noteworthy observation from the XPS results is that, in comparison to the intensity of OL or Oad peaks, the intensity of OV (Oxygen vacancy) defect peak increases when the Yb impurity concentration increases. Magnetic measurements demonstrated a diamagnetic order in pure ZnO, which converts to a ferromagnetic order with the incorporation of Yb defect states. The ferromagnetic properties of the Yb-doped CuO:ZnO nanocomposite can be ascribed to the exchange interaction of Yb3+ ions with defect states (Oxygen Vacancy) in ZnO and CuO.

Fabrication of a novel polyvinylpyrrolidone/chitosan-Schiff base/Fe2O3 nanocomposite for efficient adsorption of Pb(II) and Hg(II) ions from aqueous solution

A novel magnetic polyvinylpyrrolidone/chitosan-Schiff base/Fe2O3 (PVP/CS-SB/Fe2O3) adsorbent was prepared by one-pot facile co-precipitation route for adsorption of Pb(II) and Hg(II) ions from aqueous solution. Fourier transform infrared-spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), vibrating sample magnetometer (VSM) and Brunauer-Emmett-Teller (BET) were used to characterize the synthesized PVP/CS-SB/Fe2O3. The results predicted that the successfully synthesis of magnetic CSSB-PVP@Fe2O3. The effects of important factors such as pH solution, contact time, concentration of metal ions, adsorbent dose and co-existing ions on Pb(II) and Hg(II) adsorption were investigated. The maximum adsorption capacities of Pb(II) and Hg(II) ions at optimal conditions were 120 mg/g and 102.5 mg/g, respectively. The kinetic studies predicted that the adsorption followed the pseudo-second-order (PSO) model as chemisorption using the coordination of active sites of PVP/CS-SB/Fe2O3 with the metal ions and also n-π interactions. Reproducibility results predicted that the excellent regeneration ability after 6 adsorption cycles. According to the results of this work, the PVP/CS-SB/Fe2O3 nanocomposite is promising for Pb(II) and Hg(II) ions adsorption and can be potential as a simple, low-cost, high-efficient adsorbent for decontamination of other heavy metal ions from aqueous solution.