Vibrating Sample Magnetometry Research Articles

Oxygen vacancies enhanced photo-fenton-like catalytic degradation of rhodamine B by electrochemical synthesized α-Fe2O3 nanoparticles

Hematite is widely used as a catalyst in a photo-Fenton-like process for the oxidation of dyes. We report on the electrochemical synthesis of α-Fe2O3 nanoparticles. The structure, morphology, chemical composition, and surface chemical state of the catalyst, as well as its optical and magnetic properties, were thoroughly characterized by scanning electron microscopy, X-ray diffraction spectroscopy (XRD), shift combination scattering spectroscopy, X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). It was found that the crystal size was 63.9 nm. It was shown that the presence of Fe2+ on the surface was due to oxygen vacancies rather than impurity phases. The optical bandgap was determined to be 1.87 eV. Nanoparticles exhibit weak ferromagnetic behavior with a magnetization of 1.09 emu/g at maximum applied magnetic field 1 kOe. The catalytic activity in the photo-Fenton-like process for the degradation of Rhodamine B (RhB) dye was investigated, and the effect of working parameters, including H2O2 concentration, catalyst concentration, and RhB concentration, on the degradation efficiency was studied. The maximum degradation rate was 99.15 % in 12 min under optimal conditions. The catalyst showed long-term stability over 5 repeated cycles.

Optimizing the synthesis of ZnFe2O4 through chemical and physical methods: effects of the synthesis route on the phase purity, inversion, and magnetic properties of spinel zinc ferrite

In this work, ZnFe2O4 ferrites were prepared by chemical (coprecipitation) and ceramic (ball-milling) methods. The effects of the synthesis route on the phase purity, crystallinity, particle size distribution, and magnetic properties were investigated to identify the most appropriate conditions for the synthesis of high-quality ferrites. The samples were examined by x-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy, vibrating sample magnetometry, and Mössbauer spectroscopy. The XRD patterns revealed that a high-purity spinel phase was obtained by coprecipitation at pH ≥ 7 by calcining the pristine powder at T ≥ 900 °C, whereas a single spinel phase was obtained at T ≥ 700 °C in the ball-milling method. The crystallite size of the spinel phase exhibited general increasing trends with the increase of the pH value under the same heat-treatment conditions and with the increase of the calcination temperature. Additionally, the mean physical particle size exhibited an increasing trend with the increase of the calcination temperature. The VSM measurements revealed a noticeable degree of inversion in the spinel ferrites prepared by coprecipitation (exhibiting the highest degree at pH = 10) and an insignificant degree of inversion in the spinel ferrites prepared by the ceramic method. However, calcining the powder exhibiting the highest degree of inversion (prepared by coprecipitation at pH = 10) at 1100 °C resulted in ordering the zinc ions at tetrahedral sites of the spinel structure. Mössbauer spectra for representative zinc ferrite samples prepared by the two methods revealed a major central doublet (with a small magnetic sextet corresponding to the α-Fe2O3 phase in the sample at pH = 7). The hyperfine parameters of the doublet observed in the Mössbauer spectra of the samples, and the corresponding magnetization behavior revealed a higher degree of ionic disorder in the spinel ferrite prepared by coprecipitation.

Assessment of superconducting and structural stability of advanced Y-123 and Y-358 ceramics with Tb/Y substitution in main matrices

In this study, the performances of Y1-x(Tb)xBa2Cu3O7-δ (Y-123) and Y3-x(Tb)xBa5Cu8O18-δ (Y-358) advanced ceramics prepared by sol-gel preparation route are investigated by the advanced characterization methods including X-ray diffraction (XRD), temperature dependent resistivity (ρ-T), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM) and energy distribution spectroscopy (EDS) measurements and theoretical approaches. The EDS results illustrated that the Tb impurities were replaced successfully by the yttrium sites in the YBa2Cu3O7-y main matrix. Similarly, it was noted that the presence of excess impurities in the crystal structure led to the oxygenation problems. Electrical properties were determined by temperature dependent resistivity (ρ-T) measurements. ρ-T results indicated that Tb doping reduced the critical transition temperature (Tc) values for the transition to superconductivity for all samples in two YBCO phases. Although it appears to have negative effects of Tb ions on the number of mobile charge carrier concentrations in the σ antibonding in-plane Cu-O bonds, bipolaron formations in the polarizable lattices, oxidation states, and amplitude of the pair wave function of both phases, the other valuable properties (morphology, crystallinity quality, interaction between adjacent layers, critical current density, and flux pinning ability) were noted to improve remarkably in the case of the optimum amount in the Y-123 superconducting phase. In this context, the Y-358 superconducting phase was harshly affected by the substitution due to the change of the ortorombicity, localization problem, impurity phases, structure stabilization, crystal structure quality, crystallization system, homogeneities of oxidation states, oxygen ordering degree, and impurity scatterings. Besides, the analysis of the fluctuation induced conductivity indicated that the Y-123 ceramics with longer c-axis coherence length and less anisotropic nature exhibited well superconducting properties. Additionally, the doping ratio of x=0.01 led to the formation and distribution of more nucleation centers for the thermal fluxon motions of 2D pancake vortices. Similarly, the optimum Tb doped Y-123 system exhibited much durable to applied field strengths due to the best interaction quality between grains. Accordingly, this study recommended that the Y1-x(Tb)xBa2Cu3O7-δ advanced ceramic structure with new functionalities can find much more application areas in innovative, heavy-industrial technologies, and advanced engineering-related sectors.

Influence of temperature and gas atmosphere on the thermal decomposition of (NH4)6Mo7O24.4H2O

This study investigates the effects of gas atmosphere and synthesis temperature on the thermal decomposition of (NH4)6Mo7O24.4H2O. Samples were synthesized in a CVD furnace at temperatures of 450, 550, and 650 °C, using different gases: H2, O2, and Ar, individually. The resulting samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), and optical absorbance. XRD results revealed the formation of MoO3 in all samples produced in an O2 atmosphere. However, in samples synthesized in an inert atmosphere (Ar), a mixture of MoO3 and Mo4O11 phases was detected. The same phase mixture was observed in samples produced at 450 and 550 °C in an H2 atmosphere. However, in samples synthesized in H2 at 650 °C, MoO2 mixed with Mo4O11 was formed. Raman and FTIR spectroscopy confirmed the results obtained by XRD, and these two techniques were also used to compare samples synthesized at 550 °C in different environments. The VSM results indicate a paramagnetic response in the analyzed samples, and there is also an increase in magnetization as the percentage of the Mo4O11 phase increases. Absorbance measurements were also performed and further confirm expected changes in sample composition.

Development and characterization of lipid nanocapsules loaded with iron oxide nanoparticles for magnetic targeting to the blood-brain barrier.

Brain drug delivery is severely hindered by the presence of the blood-brain barrier (BBB). Its functionality relies on the interactions of the brain endothelial cells with additional cellular constituents, including pericytes, astrocytes, neurons, or microglia. To boost brain drug delivery, nanomedicines have been designed to exploit distinct delivery strategies, including magnetically driven nanocarriers as a form of external physical targeting to the BBB. Herein, a lipid-based magnetic nanocarrier prepared by a low-energy method is first described. Magnetic nanocapsules with a hydrodynamic diameter of 256.7 ± 8.5nm (polydispersity index: 0.089 ± 0.034) and a ξ-potential of -30.4 ± 0.3mV were obtained. Transmission electron microscopy-energy dispersive X-ray spectroscopy analysis revealed efficient encapsulation of iron oxide nanoparticles within the oily core of the nanocapsules. Both thermogravimetric analysis and phenanthroline-based colorimetric assay showed that the iron oxide percentage in the final formulation was 12 wt.%, in agreement with vibrating sample magnetometry analysis, as the specific saturation magnetization of the magnetic nanocapsules was 12% that of the bare iron oxide nanoparticles. Magnetic nanocapsules were non-toxic in the range of 50-300μg/mL over 72h against both the human cerebral endothelial hCMEC/D3 and Human Brain Vascular Pericytes cell lines. Interestingly, higher uptake of magnetic nanocapsules in both cell types was evidenced in the presence of an external magnetic field than in the absence of it after 24h. This increase in nanocapsules uptake was also evidenced in pericytes after only 3h. Altogether, these results highlight the potential for magnetic targeting to the BBB of our formulation.

Green synthesis and optimization of iron oxide nanoparticles as MRI contrast agent

Iron nanoparticles (FeNPs) derived from herbal plants are being explored as potential magnetic resonance imaging (MRI) contrast agents due to their biocompatibility and ability to perform targeted drug delivery. For the first time, the usage of various novel combinations of leaf extracts such as those of Azadirachta indica and Piper betle and extracts of two other Ayurvedic herbs – namely, Asparagus racemosus and Symplocos – was attempted for eco-friendly green synthesis of FeNPs. The nanoparticles were coated onto nanofibers made from a banana pseudo-stem (FENPs-NF) to enhance their biocompatibility. The synthesis process was optimized using response surface methodology, and techniques such as ultraviolet–visible (UV–Vis) spectroscopy, vibrating-sample magnetometry, atomic absorption spectroscopy (AAS), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT-IR) were used for characterization. Hemolytic and immune cell assays, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and MRI analysis were carried out. A peak at 325 nm observed in UV–Vis spectroscopy, AAS, FE-SEM, EDX and FT-IR proved the presence of FeNPs. Hemolytic and immune cell assays indicated biocompatibility, and the MTT assay (MCF-7) showed inhibition at 250 μg/ml. FeNPs and FeNPs-NF showed a good signal loss in MRI analysis at 1.5 T, proving their contrast agent nature. Thus, FeNPs synthesized from herbal plant sources may open a new door for potential application in the biomedical field as a chemical-free and biocompatible MRI contrast agent.

L-cysteine-coated magnetite nanoparticles as a platform for enzymes immobilization: Amplifying biocatalytic activity of Candida antarctica Lipase A

This study presents the synthesis of magnetite nanoparticles coated with L-cysteine (Fe3O4@LC) and their subsequent utilization as a support matrix for the immobilization of Candida antarctica Lipase A (CALA). The immobilization process involved physical interactions and covalent bonding mediated by glutaraldehyde. Comprehensive characterization was conducted using techniques including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM), providing compelling evidence of a successful synthesis. Under optimized conditions, employing 1 mg of protein per gram of support, pH 7 in a 25 mM phosphate buffer, and a 5 h reaction at 25 °C, immobilization on glutaraldehyde-activated support achieved an impressive yield of 85.0 % ± 2.6, accompanied by a specific activity of 212.5 ± 1.3 U/g, outperforming the physical adsorption approach. Remarkably, the immobilized enzyme exhibited higher activity than the free enzyme at alkaline and acidic pH levels. Furthermore, thermal and pH inactivation studies revealed that the biocatalyst's half-life exceeded that of free CALA by more than 8 times at pH 10. These results underscore the potential of the Fe3O4@LC-GLU-CALA system as a robust biocatalytic matrix with promising applications in biodiesel production, ester synthesis, and pharmaceutical manufacturing.

A green and economic approach to synthesize magnetic Lagenaria siceraria biochar (γ-Fe2O3-LSB) for methylene blue removal from aqueous solution.

In the printing and textile industries, methylene blue (a cationic azo dye) is commonly used. MB is a well-known carcinogen, and another major issue is its high content in industrial discharge. There are numerous removal methodologies that have been employed to remove it from industrial discharge; however, these current modalities have one or more limitations. In this research, a novel magnetized biochar (γ-Fe2O3-LSB) was synthesized using Lagenaria siceraria peels which were further magnetized via the co-precipitation method. The synthesized γ-Fe2O3-LSB was characterized using FTIR, X-ray diffraction, Raman, SEM-EDX, BET, and vibrating sample magnetometry (VSM) for the analysis of magnetic properties. γ-Fe2O3-LSB showed a reversible type IV isotherm, which is a primary characteristic of mesoporous materials. γ-Fe2O3-LSB had a specific surface area (SBET = 135.30 m2/g) which is greater than that of LSB (SBET = 11.54 m2/g). γ-Fe2O3-LSB exhibits a saturation magnetization value (Ms) of 3.72emu/g which shows its superparamagnetic nature. The batch adsorption process was performed to analyze the adsorptive removal of MB dye using γ-Fe2O3-LSB. The adsorption efficiency of γ-Fe2O3-LSB for MB was analyzed by varying parameters like the initial concentration of adsorbate (MB), γ-Fe2O3-LSB dose, pH effect, contact time, and temperature. Adsorption isotherm, kinetic, and thermodynamics were also studied after optimizing the protocol. The non-linear Langmuir model fitted the best to explain the adsorption isotherm mechanism and resulting adsorption capacity ( =54.55mg/g). The thermodynamics study showed the spontaneous and endothermic nature, and pseudo-second-order rate kinetics was followed during the adsorption process. Regeneration study showed that γ-Fe2O3-LSB can be used up to four cycles. In laboratory setup, the cost of γ-Fe2O3-LSB synthesis comes out to be 162.75 INR/kg which is low as compared to commercially available adsorbents. The results obtained suggest that magnetic Lagenaria siceraria biochar, which is economical and efficient, can be used as a potential biochar material for industrial applications in the treatment of wastewater.

Magnetic Three-Dimensional Graphene: A Superior Adsorbent for Selective and Sensitive Determination of Nitrite in Water Samples by Ion-Pair Based-Surfactant-Assisted Solid-Phase Extraction Combined with Spectrophotometry

A straightforward, fast and efficient analytical method was developed which utilizes a magnetic composite called three-dimensional graphene (3D-G@Fe3O4) as an adsorbent to recover nitrite ions (NO2−) from environmental water samples. The investigation into the synthesized adsorbent contained an examination of its morphology, chemical composition, structural attributes, and magnetic properties. This comprehensive analysis was conducted using various instrumental techniques, including Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), and vibrating sample magnetometry (VSM). The adsorbent surface was activated by adding cetyltrimethylammonium bromide (CTAB) to the sample solution. To improve the selectivity and sensitivity of the method, nitrite ions were reacted with sulfanilic acid and chromotropic acid sequentially. An orange-red azo-dye complex was formed in the presence of nitrite ions with a clear absorbance peak at 514 nm. The effect of the main experimental parameters such as the pH of the sample solution, adsorbent dosage, and CTAB dosage was explored, and the optimization process was performed using a central composite design (CCD). The linear dynamic range (20–100 ng mL−1) was determined under optimal experimental circumstances, yielding a reasonable determination coefficient (R2, 0.9993), a detection limit of 5.12 ng mL−1, an enrichment factor of 167, and precision values of 1.0% intraday and 2.9% inter-day. The methodology successfully identified minute nitrite ions in environmental water samples with relative recoveries that varied between 96.05 and 101.6 ng mL−1.

Enhancing trimethoprim pollutant removal from wastewater using magnetic metal-organic framework encapsulated with poly (itaconic acid)-grafted crosslinked chitosan composite sponge: Optimization through Box-Behnken design and thermodynamics of adsorption parameters

Trimethoprim (TMP), an antibiotic contaminant, can be effectively removed from water by using the innovative magnetic metal-organic framework (MOF) composite sponge Fe3O4@Rh-MOF@PIC, which is shown in this study. The composite is made up of magnetite (Fe3O4) nanoparticles and a rhodium MOF embedded in a poly(itaconic acid) grafted chitosan matrix. The structure and characteristics of the synthesized material were confirmed by thorough characterization employing SEM, FTIR, XPS, XRD, and BET techniques. Notably, the composite shows a high magnetic saturation of 64emug-1, which makes magnetic separation easier, according to vibrating sample magnetometry. Moreover, BET analysis revealed that the Fe3O4@Rh-MOF@PIC sponge had an incredibly high surface area of 1236.48m2/g. Its outstanding efficacy was confirmed by batch adsorption tests, which produced a maximum adsorption capacity of 391.9mg/g for the elimination of TMP. Due to its high porosity, magnetic characteristics, and superior trimethoprim uptake, this magnetic MOF composite sponge is a promising adsorbent for effective removal of antibiotics from contaminated water sources. An adsorption energy of 24.5kJ/mol was found by batch investigations on the Fe3O4@Rh-MOF@PIC composite sponge for trimethoprim (TMP) adsorption. The fact that this value was up 8kJ/mol suggests that the main mechanism controlling TMP absorption onto the sponge adsorbent is chemisorption. Chemisorption requires creating strong chemical interactions between adsorbate and adsorbent surface groups, unlike weaker physisorption. The magnetic composite sponge exhibited strong removal capabilities and high adsorption capacities for the antibiotic pollutant. The Fe3O4@Rh-MOF@PIC composite sponge also showed magnetism, which allowed for easy magnetic separation after adsorption. Over the course of 6cycles, it showed outstanding reusability, and XRD confirmed that its composition was stable. The high surface area MOF's pore filling, hydrogen bonding, π-π stacking, and electrostatic interactions were the main trimethoprim adsorption mechanisms. This magnetic composite is feasible and effective for removing antibiotics from water because of its separability, reusability, and synergistic adsorption mechanisms via electrostatics, H-bonding, and π-interactions. The adsorption results were optimized using Box Behnken-design (BBD).

Optimization of magnetic properties: Investigating the interaction of synthesis temperature, particle size, and monodomain formation in barium hexaferrite synthesized by the Pechini method

This study presents the synthesis and characterization of barium hexaferrite (BaFe12O19) powders via the Pechini method, employing controlled pH conditions (pH = 1) followed by sintering at temperatures ranging from 800 °C to 1150 °C. Structural and magnetic properties of the samples were investigated using various techniques, including Vibrating Sample Magnetometry, X-ray Diffractometry, and Scanning Electron Microscopy. Additionally,a theoretical analysis was conducted to determine the critical size required for achieving a single magnetic domain in the material. The results reveal a correlation between synthesis temperature and crystal size, ranging from 76 nm (at 800 °C) to 632 nm (at 1150 °C). Notably, samples sintered at 1050 °C exhibited exceptional magnetic properties, displaying a saturation magnetization (Ms) of 75.1 emu/g, a remanent magnetization (Mr) of 36.7 emu/g, and a coercivity (Hc) of 5.65 kOe. The particle size of these samples measured 327 nm, closely aligning with the critical diameter calculated for barium hexaferrite (378 nm) in this study. This optimal critical size was identified in sample sintered at 1050 °C, resulting in notably high coercivity values compared to those reported in previous literature. These findings highlight the significance of synthesis temperature control in tailoring the magnetic properties of barium hexaferrite, offering insights into optimizing its performance for various applications.

Tinospora cordifolia-assisted synthesis of silver ferrite nanoparticles: a multifunctional approach to photocatalytic degradation of reactive blue-13 dye, anti-bacterial efficacy, and antioxidant properties

Tinospora cordifolia-assisted synthesis of silver ferrite nanoparticles: a multifunctional approach to photocatalytic degradation of reactive blue-13 dye, anti-bacterial efficacy, and antioxidant properties

Photocatalytic degradation of methylene blue under visible light by cobalt ferrite nanoparticles/graphene quantum dots.

A simple approach was developed to synthesize cobalt ferrite nanoparticles/graphene quantum dots (CF/GQDs). The material was prepared from a homogeneous mixture of iron nitrate, cobalt nitrate, and starch at 140, 180 and 200 °C in a 24 h thermal hydrolysis process. The obtained materials were characterised by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, photoluminescence spectroscopy, vibrating-sample magnetometry, and nitrogen adsorption/desorption isotherms. Cobalt ferrite crystals of around 8-10 nm and graphene quantum dots formed directly at 200 °C. Stacking GQDs sheets onto the CF nanoparticles resulted in CF/GQDs nanoparticles. The nanocomposite exhibits satisfactory fluorescent and superparamagnetic properties, which are vital for catalytic applications. The CF/GQDs catalyse significantly the degradation of methylene blue (MB) under visible light. The catalyst can be recycled with an external magnetic field and displays suitable stability. Also, it was reused in three successive experiments with a loss of efficiency of about 5%. The CF/GQDs are considered as an efficient photocatalyst for MB degradation and other dyes.

Mössbauer and magnetization measurements of multicomponent iron garnets

Four Gd-containing iron garnets were investigated using Mössbauer spectroscopy and Vibrating Sample Magnetometry over a wide temperature range, from 4K to ∼600K. The magnetic ordering temperature and hyperfine parameters determined on the basis of Mössbauer spectra for all samples were found to be surprisingly similar, differences were only noted for the average magnetic moments, which turned out to be strongly correlated with the magnetic moments of rare earth elements present in the structure. Further differences between the systems were also highlighted in measurements in the external 9T magnetic field, especially around the compensation temperature. Changes in the nature of the Mössbauer spectra were interpreted based on the crystal field approximation confirming the correctness of the interpretation of the temperature dependence of magnetization for these samples.

Molecularly Imprinted Drug Carrier for Lamotrigine-Design, Synthesis, and Characterization of Physicochemical Parameters.

This study presents the initial attempt at introducing a magnetic molecularly imprinted polymer (MIP) designed specifically for lamotrigine with the purpose of functioning as a drug carrier. First, the composition of the magnetic polymer underwent optimization based on bulk polymer adsorption studies and theoretical analyses. The magnetic MIP was synthesized from itaconic acid and ethylene glycol dimethacrylate exhibiting a drug loading capacity of 3.4 ± 0.9 μg g-1. Structural characterization was performed using powder X-ray diffraction analysis, vibrating sample magnetometry, and Fourier transform infrared spectroscopy. The resulting MIP demonstrated controlled drug released characteristics without a burst effect in the phospahe buffer saline at pH 5 and 8. These findings hold promise for the potential nasal administration of lamotrigine in future applications.

The Structure and Magnetic Properties of Sm2Fe17Cx Compounds Prepared from Ball-Milled Mixtures of Sm2Fe17 and Carbon Nanotubes or Graphite

The processing route of Sm2Fe17 carbides is shorter than that of nitrides, which can potentially be used for cost-effective mid-performance magnets’ production. The magnetic properties of Sm2Fe17Cx compounds can be controlled at the annealing step, which allows them to be used for a variety of applications. In this work, X-ray diffraction (XRD) analysis, Mössbauer spectroscopy, scanning and transmission electron microscopy (SEM, TEM) and vibrating sample magnetometry (VSM) were used for characterization of the structure and magnetic properties of Sm2Fe17Cx compounds. The powder samples were prepared by high-energy ball milling of Sm2Fe17 mixtures with carbon nanotubes (CNT) or graphite with subsequent annealing. The formation of Sm2Fe17Cx compounds after annealing was followed by the formation of α-Fe and amorphous Sm2O3. The hyperfine field values of Fe atoms of all the Sm2Fe17 lattice sites increased by 12% on average after annealing that was caused by carbon diffusion. The coercivity of the samples peaked after annealing at 375 °C. The samples with CNT demonstrated an increase of up to 14% in coercivity and 5% in specific remanence in the range of 250–375 °C annealing temperatures.

Aluminium and praseodymium doped M-type hexaferrites for electric vehicle applications

The booming demand for electric vehicles, driven by the pursuit of enhanced efficiency, faces significant hurdles attributed to the costly integration of rare earth magnets like NdFeB. M-type strontium ferrite emerges as a promising alternative owing to its economic viability and exceptional magnetic characteristics, rendering it suitable for electric vehicle motor applications. This research focuses on the synthesis and characterization of SrFe12O19 and Sr1-xPrxFe10Al2O19 (where x = 0.00 to 0.20) hexaferrites, with praseodymium (Pr) substitution. Magnetic particles were synthesized utilizing the sol-gel auto-combustion technique, employing a calcination temperature of 1100 °C for a duration of 4 h. Structural and magnetic studies of aluminium-praseodymium (Al–Pr) doped samples are performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating-sample magnetometry (VSM). The structural analysis reveals a decrease in both particle size from 42 nm to 31.76 nm and lattice parameter with increasing doping concentration. Magnetic analysis yields crucial insights: Al3+ doping induces a substantial rise in coercivity from 5500 Oe to 10,500 Oe which is quite comparable to NdFeB, while Pr doping shows a subtle impact, enhancing remanence from 17 emu/g to 23.05 emu/g. These findings underscore the potential for optimizing magnetic properties through meticulous control of dopant concentrations in M-type hexaferrites, thereby positioning them as promising substitutes for rare earth magnets.

Efficient synthesis of benzoacridines and indenoquinolines catalyzed by acidic magnetic dendrimer

A novel solid acid catalyst with recoverability, named as Fe3O4@SiO2@TAD-G2-SO3H, was successfully synthesized by immobilizing sulfonic acid groups on triazine dendrimer-modified magnetic nanoparticles. This nanomaterial structure and composition were thoroughly characterized using various analytical techniques, including thermogravimetric analysis (TGA), elemental analysis, Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, acid–base titration, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The acid-decorated magnetic dendrimer was served as a highly effective catalyst for the synthesis of tetrahydrobenzo[c]acridin-8(9H)-one and benzo[h]indeno[1,2-b]quinoline-8-one derivatives. The reaction proceeded smoothly under mild conditions through the one-pot condensation of aromatic aldehydes, 1-naphthylamine, and either dimedone or 1,3-indanedione, affording the desired products in high yields ranging from 90 to 96%. The catalyst was easily separated from the reaction mixture by employing a magnetic field, allowing for its recycling up to five times with slight loss in its activity (only 10%). Nearly, quantitative recovery of catalyst (up to 95%) could be obtained from each run. So, this catalyst facilitates the reaction progress and simplifies the purification process. Other remarkable features of this method are operational simplicity, excellent yields, mild condition, and a wide range of substrate applicability.

Magnetic membranes based on PVA-SPION for hyperthermia and dielectric applications

Magnetodielectric membranes were spun by electrospinning ferrofluids containing Superparamagnetic Iron Oxide (SPION) in a carrier liquid of Polyvinyl alcohol(PVA) for various loadings of iron oxide. These membranes were characterised using X-ray diffractometer (XRD), Field Emission Scanning Electron Microscopy (FESEM),Vibrational Sample Magnetometry (VSM),Fourier Transform Infrared Spectroscopy (FTIR) and UV–visible spectroscopy (UV–vis) and found to be of good quality having adequate magnetic and dielectric properties. The iron oxide particles were found to be ∼9 nm in size and superparamagnetic in nature. The addition of iron oxide led to a systematic increase in both magnetic and dielectric properties. A maximum saturation magnetization of ∼6.3 emu g−1 and a dielectric constant of ∼50 was obtained for a loading of 40 percentage of Iron oxide. A dielectric transducer was fabricated using the membranes. These membranes also exhibited magnetic hyperthermia as evidenced by magnetic hyperthermia measurements. They are found to be potential candidates for hyperthermia applications as wearables. The method of employing a ferrofluid can be adopted for spinning membranes based on other than PVA/SPION. If the loading is optimised these membranes can be employed as Magnetodielectric transducers.

Exploring the sustainable synthesis pathway and comprehensive characterization of magnetic hybrid alumina nanoparticles phase (MHAl-NPsP) as highly efficient adsorbents and selective copper ions removal

This study introduces a novel method for producing magnetic hybrid alumina nanoparticles phase (MHAl-NPsP) tailored specifically for efficient copper (II) ion removal from wastewater. The synthesized MHAl-NPsP underwent comprehensive characterization, including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) revealing its rough and porous surface morphology, X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) analysis, BET analysis for surface area measurements, TGA analysis confirming high thermal stability, vibrating sample magnetometry (VSM) analysis confirming successful synthesis through detection of magnetic properties, and X-ray Photoelectron Spectroscopy (XPS) analysis. Remarkably, MHAl-NPsP demonstrated an exceptional adsorption capacity of 52.5 mg/g under optimized conditions of pH 3.5 and an initial copper concentration of 30 mg/L, surpassing previous results significantly. Detailed investigation into adsorption kinetics revealed a pseudo-second-order model, suggesting a predominant chemisorption mechanism. Moreover, analysis using the Langmuir isotherm model showed excellent fitting with an R² value of 0.994, indicating monolayer coverage as the primary adsorption mode. Notably, pH dependency studies indicated enhanced adsorption efficiency with decreasing pH levels, highlighting the significant role of electrostatic interactions. This study underscores the effectiveness and environmental sustainability of the green synthesis approach employed for MHAl-NPsP. Utilizing their magnetic properties, MHAl-NPsP facilitate easy separation and retrieval of adsorbed copper ions, making them highly promising for practical applications in wastewater treatment. The findings advocate for the development of eco-friendly adsorbents to tackle water pollution challenges, providing promising solutions for sustainable environmental remediation.