Vibrating Sample Magnetometer Research Articles

Effect of cation disorder on basic parameters of ZnFe2O4 nano-particles synthesized by honey mediated solution combustion technique

Nanotechnology contracts by the invention and practice of material using nanoscale dimension. Nanoscale measurement delivers nano-particles a bulky surface area (S) to volume ratio, hence very specific properties. Bulk zinc ferrite (ZnFe2O4) exhibits anti-ferromagnetism, with Néel temperature of 10K, is paramagnetic at room temperature. It displays normal spinel structure with Zn2+ has exclusive tetrahedral - A site preference, whereas Fe3+ ions occupy the octahedral - B site. Cationic disorder induced fractional overturn of the spinel structure, owing to partial immigration of Fe3+ ions from B to A site can prompt ferrimagnetism in nano zinc ferrite. Due to the large ratio of toxic chemicals and extreme environment employed in the chemical and physical production of these ferrites, green methods employing the use of bacteria, plants fungus have been adopted. Present work reports comprehensive study of the synthesis, structural and magnetic investigation of room temperature ferrimagnetism in ZnFe2O4 nanoparticles, prepared by sol gel auto-combustion mode and green synthesis method. Effect of conventional thermal annealing (ann. at 600oC for 3 hours) on magnetic properties is also reported. The structural and magnetic characteristics of as prepared and annealed ZnFe2O4 samples were determined by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). XRD confirms the formation of single-phase nano-crystalline cubic spinel structure of the samples.

Magnetic chitosan-functionalized waste carton biochar composites for efficient adsorption of anionic and cationic dyes

In this study, BC-CoFe2O4-CS magnetic composite was successfully prepared from waste cardboard and investigated as an efficient adsorbent for the removal of amaranth and methyl orange in aqueous solution. First, the fibers obtained from the cardboard waste were carbonized by a hydrothermal process to produce biochar. Subsequently, the final magnetic composites were synthesized by in situ growth and Schiff base crosslinking reactions. The composites were characterized by zeta potential, Brunauer–Emmett–Teller measurements, Fourier transform Infrared spectroscopy, Scanning electron microscopy, Energy dispersive spectrometer,X-ray Diffraction, Thermogravimetry analysis and Vibrating sample magnetometer. The effects of adsorbent dosage and initial solution pH on dye removal efficiency were studied. The results showed that the maximum adsorption capacity of amaranth could reach 500.6 mg·g−1 at pH = 2, the adsorbent dosage of 0.5 mg·ml−1, and methyl orange could reach 644.0 mg·g−1 at pH = 4, the adsorbent dosage of 0.5 mg·ml−1. The adsorption process followed the pseudo-second order kinetic models and Langmuir isotherm. BC-CoFe2O4-CS was easily separated from the aqueous solution due to the loading of CoFe2O4 magnetic nanoparticles. Besides, the BC-CoFe2O4-CS could be further used after the adsorption experiments with or without desorption and still showed good adsorption performance in the actual water samples. Therefore, it is expected that the composite material prepared from waste cartons can be used for the treatment of dye-containing wastewater due to its low cost, high efficiency, and simple application.

Investigation on structural, morphological, optical, magnetic properties of CdO-CoFe2O4 nanocomposites and their photocatalytic application

The nanoparticles of pure CdO and CoFe2O4 were synthesized by co- precipitation technique and the composites [(CdO)x- CoFe2O4)1−x] [(DF1 (x = 0.6), DF2 (x = 0.4), DF3(x = 0.2)] were synthesized via sono chemical route. X- ray diffraction (XRD) study validated the presence of two phases in the material. The crystallite size calculated using Debye Scherrer equation were in nano range having size from 8 nm to 59 nm. The morphological and compositional studies of the synthesized material are done by Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive Spectroscopy (EDS) respectively. EDS spectroscopy confirms the conversion of initial precursor salts into final material according to their stoichiometric ratios. The optical properties of the material were examined by ultra violet – visible (UV-Vis) Spectroscopy. Further, Tauc’s plot was employed to obtain the band gap of the material. The band gap (2.5 to 2.9 eV) falls within the range of visible light (typically 400 to 700 nm). This means that the material can effectively absorb visible light photons, which is a crucial requirement for many photocatalytic reactions. The cationic and anionic bonding at different interstitial sites was revealed by Fourier transform infrared spectroscopy (FTIR). The magnetic properties of the material were examined through Vibrating sample magnetometer (VSM). M-H curve gives information about saturated magnetization (Ms), coercivity (Hc) and retentivity (Mr) etc of the material. The maximum obtained values for Ms, Hc and Mr are 41.921 emu/g, 1651.6 Oe and 14.2 emu/g respectively, which confirm the ferrimagnetic nature of the material. The photocatalytic activity of the material under ultraviolet region is evaluated for Methylene Blue (MB) dye. The best photocatalytic results were shown by DF1 sample with discoloration efficiency of 84.5%. The active participation of hydroxyl ion (OH-) and singlet oxygen ion (O2-) is confirmed through scavenger test using Isopropyl alcohol (IPA) and Disodium ethylene diaminne tetraacetic acid (EDTA 2NA) respectively. The dye removal kinetics was tested by using various order rate models. Further to check the stability of the material, recycling efficiency of the material has been calculated for four consecutively cycle.

A chemometric approach based on response surface methodology for optimization of antibiotic and organic dyes removal from water samples

In this study, the Fe3O4/rGO/Ag magnetic nanocomposite was synthesized and employed as an adsorbent for the removal of tetracycline (TC), crystal violet (CV), and methylene blue (MB) from water samples. The influential parameters in the removal process were identified and optimized using response surface methodology (RSM). Characterization of the product was performed through field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX), vibrating-sample magnetometer (VSM), and X-ray diffraction (XRD) analysis. XRD and SEM analysis revealed the successful synthesis of the Fe3O4/rGO/Ag nanocomposite. EDX analysis elucidated the accuracy and clarity of the chemical composition of the magnetic nanocomposite structure. Additionally, the separation of the nano-adsorbent from the solution can be achieved using a magnetic field. Maximum removal of analytes was obtained at pH of 6, amount of nanocomposite 0.014 g, ultrasonic time of 8 min and concentration of 21 mg L−1. Under optimal conditions, the removal efficiencies for TC, CV, and MB were 91.33, 95.82, and 98.19%, respectively. Also, it was observed that after each adsorption–desorption cycle, Fe3O4/rGO/Ag magnetic nanocomposite had good stability to remove TC, CV, and MB. Achieving nearly 98% removal efficiency in optimal conditions showed that Fe3O4/rGO/Ag magnetic nanocomposite is an effective adsorbent for removing TC, CV, and MB from wastewater samples.

Tuning the Magnetic Behavior of Zinc Ferrite via Cobalt Substitution: A Structural Analysis.

Cobalt-doped zinc ferrite is a contemporary material with significant structural and magnetic characteristics. Our study explores the magnetic properties of cobalt-substituted zinc ferrite (ZnxCo1-xFe2O4), synthesized via a simple sol-gel method. By varying the cobalt ratio from 0 to 0.5, we found that zinc substitution impacts both the magnetization and lattice parameters. FTIR analysis suggested the presence of functional groups, particularly depicting an M-O stretching band, within octahedral and tetrahedral clusters. X-ray diffraction analysis confirmed the phase purity and cubic structure. The synthesized materials exhibited an average particle size of 24-75 nm. Scanning electron microscopy revealed the morphological properties, confirming the formation of truncated octahedral particles. In order to determine the stability, mass loss (%), and thermal behavior, a thermal analysis (thermogravimetric analysis (TGA)/differential thermal analysis (DTA)) was performed. The magnetic properties of the synthesized ferrites were confirmed via a vibrating sample magnetometer (VSM). Finally, the highest saturated magnetization and lowest coercivity values were observed with higher concentrations of the cobalt dopant substituting zinc. The synthesized nanomaterials have good stability as compared to other such materials and can be used for magnetization in the near future.

The Field-Dependent Magnetic Viscosity of FeNdB Permanent Magnets.

The time-dependent decrease of the magnetic polarization of magnet materials in the presence of an opposing field is well known as the magnetic viscosity or magnetic aftereffect. In previous studies, magnetic viscosity was usually measured in fields when in the vicinity of coercivity HcJ, and this was conducted in order to understand the coercivity mechanism in magnetic materials. In this study, the magnetic viscosity of commercial FeNdB magnets is determined at opposing fields weaker than HcJ and at different temperatures in the range from 303 to 433 K (i.e., from 30 to 160 °C) by means of a vibrating sample magnetometer (VSM). As a result, the parameter Sv, which describes the magnetic viscosity in the material, was found to increase with increases in the opposing field. Furthermore, both the parameter Sv and its dependence on the temperature were found to correlate with the coercivity HcJ of the material. Also, a difference with regard to the parameter Sv for the materials measured in this study with similar magnetic properties, but which had undergone different types of processing, could not be found. Knowledge of the field- and temperature-dependent behavior of the magnetic viscosity of FeNdB magnets allows for better estimations over the lifetime of a component under operating conditions with respect to the magnetic losses in FeNdB magnets that are used in electric components.

On the origin of systematic errors in VSM torque curves

Magnetic anisotropy (MA) is a basic and crucial magnetic property which describes how the magnetic properties change with field angle in a magnetic composite. Torque measurements are normally used to measure a sample’s anisotropy constant and can be determined directly using a torque magnetometer (TM) or indirectly using a vibrating sample magnetometer (VSM). Most TM only operate at room temperature. However, a biaxial VSM allows straightforward torque measurements at varying temperatures. VSM torque curves comprise a 2θ background caused by small misalignments of the sample on the sample rod, and/or a non-azimuthal symmetric sample shape. These errors originate from the position dependence of the pickup coil sensitivity matrix. Here, the magnetic torque of a strontium ferrite/PA-12 3D printed samples was explored using biaxial VSM and compared to measurements done with a true torque magnetometer. Torque curves were taken from 16-22kOe every 2kOe on a 4.8 mm wire and a 1.23 mm dot sample using a MicroSense EZ9 VSM. Fourier analysis was used to determine the second harmonics from each torque curve. The biaxial torque curves of the wire samples have a much larger torque amplitude which is mainly due to the crosstalk of the y-coil set. Crosstalk originates from the non-azimuthal symmetric shape of the sample and due to the wobble originating from small sample misalignments on the sample rod. Background can be minimized by using samples with near cylindrical symmetry and using a microscope when mounting the sample on the sample rod.

Investigation of Visible and UV Light‐Induced Photocatalysis Properties of Oleic Acid‐Ligated Cobalt‐Mixed Magnesium Ferrite Nanoparticles for Photodegradation of Cationic and Anionic Dyes

Owing to numerous potential applications in multiple fields, the study of nanosized magnetic spinel ferrites has been gaining significance. Synthesis and characterization of high‐quality magnetic nanocrystals with narrow size distribution, enhanced magnetic saturation, and outstanding properties for bioenvironmental applications are presented in the current study. Nanoparticles of oleic acid‐ligated Co0.5‐mixed Mg0.5Fe2O4 were prepared by a simple thermal decomposition method. The effect of cobalt (Co2+) content on the structural, optical, magnetic, and thermal properties of magnesium ferrite was assessed by powder X‐ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT‐IR), and vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). High‐resolution transmission electron microscopy (HR‐TEM) and energy dispersive X‐ray (EDX) spectroscopy were used to determine morphology and composition, respectively. Nanoparticles produced are highly crystalline and homogeneous, having an average size of 10 nm, with large saturation magnetization (61 emu/g) and high magnetic moment. Photocatalytic properties of prepared nanocrystals were studied by degradation of anionic Orange II and cationic methylene blue (MB) dyes under UV and visible light radiations for different time intervals. The anionic Orange II dye exhibited higher degradation, up to 97.2% and 92.2%, within a 90‐minute time period of ultraviolet and visible light irradiation, respectively. The cationic MB dye also displayed significant degradation, up to 91.9% and 93.8%, within 300 min under UV and visible light sources, respectively. The synthesized OA‐ligated nanoparticles degrade cationic and anionic dyes more effectively than previously reported in the literature and, thus, can be prime candidates for effective photo catalytic dye degradation and waste water cleaning applications, through the harvesting of ambient solar energy.

Low-temperature manufacturable, recyclable, and reconfigurable liquid-metal bonded NdFeB magnets for sensors and robotics

This work presents a recyclable liquid-metal/NdFeB composite magnet (LM magnet) with a reconfigurable shape and polarity. Taking advantage of the low-temperature phase-transition property of LMs, we can re-orient the NdFeB particles and reshape the LM magnets, to produce complex magnetization profiles or complex structured magnets. The manufacturing of LM magnets was realized at low temperatures by using a template and paired permanent magnets. The microscopic morphology and elemental composition of the LM magnet were analyzed by scanning electron microscopy and energy dispersive spectroscopy, respectively. The magnetic properties and phase-transition properties of the LM magnet were analyzed using a vibrating sample magnetometer (VSM) and a differential scanning calorimeter. The experimental results verified that the LM magnet can be recycled, reconfigured, and welded. The configurable magnetization profile with a resolution of up to 800 µm demonstrates that manufacturing of complex magnetic poles can be achieved through this technique. Finally, three application cases show the application prospects of the LM magnet in robots and sensors.

MgFe2O4@Tris magnetic nanoparticles: an effective and powerful catalyst for one-pot synthesis of pyrazolopyranopyrimidine and tetrahydrodipyrazolopyridine derivatives.

Magnesium (Mg) as a metal has wide applications, but its use in chemical reactions is rarely reported. Currently, magnesium catalytic processes are being developed to synthesize basic chemical compounds. Therefore, an effective and recyclable nano-catalyst was synthesized using MgFe2O4@Tris in this study. The structure of MgFe2O4@Tris was characterized by various techniques including Fourier-transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM) techniques. Finally, the catalytic activity of this nano-catalyst was evaluated for the synthesis of pyrazolopyranopyrimidine and tetrahydrodipyrazolopyridine derivatives. Among the advantages of this catalyst are its high catalytic activity, high yields, use of environmentally friendly solvents, easy magnetic separation, and the possibility of reusing the catalyst.

Fe3O4@SiO2 core/shell functionalized by gallic acid: a novel, robust, and water-compatible heterogeneous magnetic nanocatalyst for environmentally friendly synthesis of acridine-1,8-diones.

In this study, we conveniently prepared a novel robust heterogeneous magnetic nanocatalyst using a Fe3O4@SiO2 core/shell stabilized by gallic acid. The catalyst was completely characterized by various physicochemical techniques, including infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic light scattering (DLS), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA), potentiometric titration, energy dispersive X-ray microanalysis (EDX), vibrating sample magnetometer (VSM), zeta potential analysis, and BET. The potential ability of the newly developed sulfonated nanocatalyst was then exploited in the multicomponent synthesis of acridine-1,8-dione derivatives by considering the green chemistry matrix and under mild conditions. Various aldehydes and amines were smoothly reacted with dimedone, affording the desired products in good to excellent yields. The introduction of sulfonic groups using gallic acid allowed the development of a water-compatible and highly recyclable catalytic system for reactions in an aqueous environment. The prepared catalyst can be readily magnetically separated and reused eight times without significant loss of activity. High synthetic efficiency, using a recyclable and eco-sustainable catalyst under mild conditions, and easy product isolation are salient features of this catalytic system, which makes this protocol compatible with the demands of green chemistry.

Structural and magnetic properties of Fe and Ni co-doped SnO2 nanoparticles prepared by co-precipitation method

In this research work Fe and Ni co-doped Tin oxide (SnO2) nanoparticles have been prepared by co-precipitation method. The samples were prepared at various combination of Fe and Ni from 0% up to 10%. The produced nanoparticles were studied by x-ray diffraction (XRD), Scanning Electron Microscopy (SEM), UV–vis Spectrophotometer, Fourier Transformation Infrared Spectroscopy (FTIR) and Vibrating Sample Magnetometer (VSM). The XRD study reveals the formation of rutile structure of the undoped and doped SnO2 nanoparticles with the average crystallite size of 1.5–10.8 nm. Metal oxide bonding is confirmed through FTIR measurement. Optical band gap redshift (3.9 to 3.64 eV) with doping of Fe and Ni atom is observed. SEM image confirms the formation of spheroidal nanoparticles and size of the nanoparticle varies from 36 to 15 nm. The VSM study shows the ferromagnetic phase transition at 7% Ni, Fe doped SnO2 nanoparticles. This ferromagnetism arises for the oxygen vacancies and defect states. Further, increase of doping concentration of 10%, nanoparticles show the phase transition from ferromagnetic to paramagnetic. Such transition can be applicable in hyperthermia treatment and memory devices.

Green and efficient magnetic micro-solid phase extraction utilizing tea waste impregnated with magnetic nanoparticles for the analysis of ibuprofen in water samples by using UV-vis spectrophotometry.

A green method based on magnetic micro-solid phase extraction (MNP-TW-μ-SPE) of tea waste impregnated with magnetic nanoparticles (MNP-TW) was developed for the extraction of ibuprofen (IBP) in water samples prior to UV-Vis spectrophotometric analysis. Experimenting parameters that affect the extraction efficiency of IBP, such as pH of the sample solution, sorbent dosage, extraction time, ionic strength, volume of the sample, type of desorption solvent, desorption time, and desorption volume, were studied and optimized in detail. The characterization studies for the MNP-TW were carried out by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectrometry (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, a vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). Under the optimum conditions, the linearity ranges from 30 to 700 μg L-1 for IBP, with determination coefficients (R2) of 0.9983. The limit of detection (LOD) and limit of quantification (LOQ) were 9.40 μg L-1 and 28.50 μg L-1, respectively. The method also demonstrated good precision in reproducibility (RSD ≤ 1.53%), repeatability (RSD ≤ 1.48%), and recovery (86-115%). This method represents the advantages of low solvent consumption, flexibility, and better sensitivity compared to other studies employing spectrophotometric analysis. The usage of tea waste in the extraction process presents many advantages, as it is biodegradable, versatile, and contributes to an intelligent and sustainable economic strategy projected toward a circular economy approach.

Facile and green synthesis of recyclable, environmentally friendly, chemically stable, and cost-effective magnetic nanohybrid adsorbent for tetracycline adsorption

Antibiotic contamination of water sources, particularly tetracycline (TC) contamination, has emerged as one of the global issues that needs action. In this research, ZnCoFe2O4@Chitosan (Ch) as a magnetic nanohybrid adsorbent was synthesized using the microwave-assisted co-precipitation method, and their efficiency for the TC adsorption process was investigated. FESEM (Field Emission Scanning Electron Microscope), EDX (Energy Dispersive X-ray), Mapping and line Scan, XRD (X-Ray Diffraction), FTIR (Fourier Transform Infrared Spectrometer), VSM (Vibrating Sample Magnetometer), Thermogravimetric analysis (TGA) and BET (Brunauer Emmett Teller) techniques were used to check and verify its physical and chemical properties. The removal of TC via the adsorption process from synthetic and real wastewater samples was investigated. The factors determining the TC adsorption process, comprising tetracycline concentration (5–30 mg/L), adsorbent dosage (0.7–2 g/L), contact time (2–45 min), and pH (3–11), were evaluated. The removal effectiveness for the synthetic sample and the real wastewater sample was 93 % and 80 %, respectively, under the ideal TC adsorption process parameters of pH 3, adsorbent dosage 1 g/L, TC initial concentration 5 mg/L, and contact time 30 min. According to kinetic and equilibrium studies, the adsorption of TC by ZnCoFe2O4@Ch follows pseudo-second-order kinetics and the Freundlich isotherm. Additionally, it was determined through the analysis of thermodynamic data that the process of exothermic adsorption is spontaneous and is followed by a decrease in disorder (ΔH = −15.16 kJ/mol, ΔS = −28.69 kJ/mol, and ΔG = −6.62 kJ/mol). After five cycles of recovery and regeneration, the ZnCoFe2O4@Ch magnetic nanocomposite was able to remove 65 % of the TC pollutant and had good chemical stability. The results showed that the magnetic nano-adsorbent ZnCoFe2O4@Ch is a novel magnetic nano-adsorbent with high adsorption capacity that can be utilized to eliminate pharmaceutical contaminants from aqueous solutions.

Preparation of berberine magnetic nanoparticles and their inhibition of human gastric cancer BGC-823 cells

A new drug delivery system loaded with the drug berberine on carboxymethyl chitosan-coated magnetic nanoparticles (Fe3O4@CMCS-BBR) was prepared and characterized through x-ray diffraction, Fourier transform-infrared spectroscopy, a vibrating sample magnetometer, and transmission electron microscopy. By comparing the size of the uncoated nanoparticles (39.26 nm) and the size of the coated magnetite nanoparticles (73.75 nm), it was found that with the CMCS coating on the magnetite nanoparticles, the dispersion of the nanoparticle improved. The optimum pH testing showed a higher drug encapsulation of 51.23% and drug loading of 17.10% at a pH of 5.5 because of the better interaction of the NH3+ group with the negative functional groups of the CMCS. Furthermore, 85.89% of the drug was released within 72 h. The CCK-8 test results showed that Fe3O4@CMCS-BBR magnetic nanocomposites had good biocompatibility with gastric cancer BGC-823 cells and that Fe3O4@CMCS-BBR effectively inhibited the proliferation of cancer cells. The magnetic experimental results showed that Fe3O4@CMCS-BBR had good responsiveness to external magnetic fields and aggregated in the presence of a magnetic field. The results of targeting experiments showed that fluorescein isothiocyanate emitted a strong yellowish fluorescence in cells, which became stronger over time, and the killing effect on cancer cells became greater. The apoptosis results showed that the apoptosis rate induced by the magnetic nanodrug was 54.90%, indicating that the drug had a promoting effect on the apoptosis of BGC-823 cells.

THE POWDER OF Co64Nb30B6 OBTAINED BY MECHANICAL ALLOYING

This work aims to synthesize the alloy Co64Nb30B6 through mechanical alloying using a planetary ball mill. A disc rotation per minute and a ball/powder weight ratio of 300 rpm and 10:1 were used, with a milled time of 10 h, respectively. The characterization of the Co64Nb30B6 alloy was performed by X-ray diffraction (XRD), examined by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS), thermoanalytical techniques (TGA/DTA), vibrating sample magnetometer (VSM) and confirmed by Braunauer, Emmet e Teller (BET) method type IV isotherms with a hysteresis loop for mesoporous materials. The results indicated that the evolution of the amorphous phase in the Co64Nb30B6 composition through the mechanical alloying process exhibited good soft magnetic properties with the addition of the metalloid element B and its excellent unique ferromagnetic properties. Through thermoanalytical analysis (TGA/DTA), it was shown that at higher temperatures, Co and Nb ions are oxidized by the environment and, therefore, the mass can be slightly increased to 14.9% and a probable contribution of boron in evolution stability thermal and magnetic in the amorphous phase, respectively. This suggests that the newly developed high-performance amorphous alloy Co64Nb30B6 has great application potential.

The adsorption properties and mechanisms of magnetic carbon-silicon composites in situ prepared from coal gasification fine slag.

A novel magnetic carbon-silicon composite (Fe-HH-CGFS) was prepared from solid waste coal gasification fine slag (CGFS) by a two-step acid leaching and one-step chemical co-precipitation process, which was optimized using a 3-factor, 3-level Box-Behnken design and then analyzed for correlation. Fe-HH-CGFS was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM) measurements. The results demonstrated that Fe-HH-CGFS had a reverse spinel structure with an average particle size of 5.14 nm, exhibiting a microporous/mesoporous structure with a specific surface area (SSA) of 196.84 m2 g-1 and pore volume of 0.346 cm3 g-1. Furthermore, Fe-HH-CGFS could achieve 97.59% removal efficiency of rhodamine B (RhB) under the optimal conditions: an initial concentration of RhB of 100 mg L-1, an adsorption time of 60 min, and a dosage of Fe-HH-CGFS of 1.0 g L-1. The pseudo-second-order model and the Langmuir isotherm satisfactorily described the adsorption behavior. The results indicated that the RhB removal process was a single-molecule layer endothermic adsorption, which is dominated by chemical adsorption reactions. This work is expected to provide an alternative route for the high-value utilization of CGFS and offer a valuable insight for the recycling of other solid wastes, aligning with the green development concept of "treating wastes with wastes".

Synthesis of azepane-acridine heterocyclic adducts assisted by the catalytic influence of γ-Fe2O3@TiO2-Vitamin B1 and evaluation of their medicinal potential through in vitro antimicrobial, QSAR, and molecular docking studies

Present work elicits synthesis of novel azepane-acridines, assisted by titania-encapsulated γFe2O3 nanoparticles supported on Vitamin B1 (γFe2O3@TiO2-Vitamin B1) as a new magnetically recyclable heterogeneous nano-catalytic system. The reaction was accomplished using biocompatible PEG-200 (Polyethylene glycol) as the solvent under ultrasonic irradiations. The structure and morphology of synthesized magnetic nano-catalyst was ascertained based on data obtained from powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), Fourier transform infrared (FT-IR), and VSM (Vibrating-sample magnetometer) TGA, DTA and DTG techniques. The characteristic size of the prepared heterogenous nano-catalyst is 34.62 nm. Also, the structures of all the synthesized azepane-acridine heterocyclic scaffolds were corroborated through spectro-analytical data. These new compounds were found to have remarkable biological activity profile against the bacterium S.aureus with IC50 values ranging from 1.41 to 2.75 µg/mL. Further, these in-vitro studies were correlated with statistically significant 2D/3D- QSAR models. The best 2D-QSAR models reveal the positive influence of slogp and Vander Waal Surface area descriptors while the negative influence of the polar surface area and T_2_N_6 descriptors on the bioactivity with ideal values of squared correlation coefficient (r2), cross-validated correlation coefficient (q2) with high values of Fisher ratio (F-test) indicating the model to be statistically relevant. The finest 3D-QSAR models MLR (Multiple Linear Regression method) provide practical information in the characterization and differentiation of compound binding sites. Moreover, molecular docking studies were performed to evaluate the antifungal activity of synthesized scaffolds against the black fungi crystal protein, indicating remarkable bioassay scores. Atom economy, practical feasibility, cost-effectiveness, minimum reaction time, High yields, and an additive-free process are the foremost advantages of the developed methodology.

Magnetic Crosslinked Porcine Pancreatic Lipase Aggregates for Transesterification Process

Lipases have been used in industrial processes as biocatalysts for transesterification reactions. The synergism between enzymes and magnetic properties may be reached by using magnetic nanoparticles (MNPs) as support to immobilize them in aggregate structures, denominated by magnetic crosslinked enzyme aggregates (MCLEA). One of the advantages of such supports is the possibility of using magnetic separation for enzyme recovery, reducing costs and allowing reuse in continuous systems. Here, porcine pancreatic lipase (PPL) was immobilized onto functionalized magnetite support (Fe3O4-APTS) with a protein binding efficiency of 78.84%. Physical and chemical properties of the nanoparticles and immobilized lipase were characterized by X-ray diffraction (XDR), transmission electron microscopy (TEM), infrared spectroscopy (FTIR), dynamic light scattering (DLS), zeta potential, vibrating sample magnetometer measurements (VSM), and 57Fe Mössbauer spectroscopy. The immobilized lipase additionally exhibited improved stability across wide pH and temperature ranges compared with free lipase. The immobilized derivate also attained good reusability, maintaining 61.37% of its initial activity after 6 reaction cycles. Through magnetic behavior and also because of its surface modification to crosslinking the enzyme, the MCLEA produced in this work has enhanced the biocatalytic activities of PPL.

Synthesis of CoFe2O4/mesoporous-carbon hybrid nanocomposite with enhanced microwave absorption in K and Ka-band

In the present investigation, CoFe2O4/mesoporous-carbon nanocomposites were synthesized using a facile hydrothermal method and demonstrate their dual band (K and Ka-band) microwave absorption properties, where radiation from high-resolution and close-range radars, space telescopes, and wireless point-to-point microwave communication systems populates. XRD results confirmed the pure phase formation of CoFe2O4 nanoparticles. Vibrating sample magnetometer shows a decrease in magnetization value for CoFe2O4/mesoporous-carbon nanocomposites that can be attributed to the increasing contents of non-magnetic mesoporous carbon. The reflection loss of the hybrid nanocomposite reached −31 dB at a matching thickness of 2.5 mm and effective absorption bandwidth was 4.4 GHz. The enhanced microwave absorption properties derive from the synergistic effect amid dielectric and magnetic loss of mesoporous-carbon and ferrite, respectively, and better impendence matching at their interface. In addition, the dielectric loss can be associated with polarization relaxation and mesoporous carbon conductivity and the magnetic loss arises from the natural resonance of ferrite materials. The high reflection loss and wide absorption bandwidth display that CoFe2O4/mesoporous-carbon nanocomposite having admirable microwave absorption performances can be a capable candidate for stealth technology and in advanced communication systems.