Saturation Magnetization Value Research Articles

Chemical activation and magnetization of carbonaceous materials fabricated from waste plastics and their evaluation for methylene blue adsorption.

In this study, novel adsorbents were synthesized via the activation and magnetization of carbon spheres, graphene, and carbon nanotubes fabricated from plastics to improve their surface area and porosity and facilitate their separation from aqueous solutions. Fourier transform infrared spectroscopy "FTIR", X-ray diffraction "XRD", energy-dispersive X-ray spectroscopy "EDX", transmission electron microscope "TEM", and X-ray photoelectron spectroscopy "XPS" affirmed the successful activation and magnetization of the fabricated materials. Further, surface area analysis showed that the activation and magnetization enhanced the surface area. The weight loss ratio decreased from nearly 60% in the case of activated graphene to around 25% after magnetization, and the same trend was observed in the other materials confirming that magnetization improved the thermal stability of the fabricated materials. The prepared carbonaceous materials showed superparamagnetic properties according to the magnetic saturation values obtained from vibrating sample magnetometry analysis, where the magnetic saturation values were 33.77, 38.75, and 27.18 emu/g in the presence of magnetic activated carbon spheres, graphene, and carbon nanotubes, respectively. The adsorption efficiencies of methylene blue (MB) were 76.9%, 96.3%, and 74.8% in the presence of magnetic activated carbon spheres, graphene, and carbon nanotubes, respectively. This study proposes efficient adsorbents with low cost and high adsorption efficiency that can be applied on an industrial scale to remove emerging pollutants.

Graphene-based Sm-doped Co-ferrite for environmental applications

A graphene-based Sm-doped Co-ferrite CoSmFe-G nanosample was created using the citrate auto-combustion method. It acts as an antibacterial agent and heavy metal remover. The sample’s physical properties were analyzed using various techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (FE-SEM), zeta potential, and vibrating sample magnetometer (VSM) measurements. The XRD results confirmed the presence of a single-phase cubic spinel structure. The experimental results indicated that doping with graphene and samarium significantly altered the magnetic properties of CoSmFe-G nanoparticles, reducing the saturation magnetization (MS) values to 35.759 emu/g. The sample showed antibacterial properties against both gram-positive and gram-negative bacteria, with inhibition zones measuring 12–14.5 mm in diameter. Additionally, the sample exhibited efficient (Pb2+) adsorption, with a maximum removal capacity of 99.8% and a multilayer adsorption mechanism indicated by the pseudo-second-order isotherm and Freundlich model matching. The study explores the binding interactions for lead removal and highlights the potential of using graphene-based Sm-doped Co-ferrite (CoSmFe-G) nano samples as a bio-adsorbent and antibacterial agent. This could lead to practical and efficient solutions for water disinfection.

Zinc/Magnesium Ferrite Nanoparticles Functionalized with Silver for Optimized Photocatalytic Removal of Malachite Green.

Water pollution is a major environmental challenge. Due to the inefficiency of conventional wastewater treatment plants in degrading many organic complex compounds, these recalcitrant pollutants end up in rivers, lakes, oceans and other bodies of water, affecting the environment and human health. Semiconductor photocatalysis is considered an efficient complement to conventional methods, and the use of various nanomaterials for this purpose has been widely explored, with a particular focus on improving their activity under visible light. This work focuses on developing magnetic and photoactive zinc/magnesium mixed ferrites (Zn0.5Mg0.5Fe2O4) by sol-gel and solvothermal synthesis methods, which are two of the most important and efficient methods used for the synthesis of ferrite nanoparticles. The nanoparticles (NPs) synthesized by the sol-gel method exhibited an average size of 14.7 nm, while those synthesized by the solvothermal method had an average size of 17.4 nm. Both types possessed a predominantly cubic structure and demonstrated superparamagnetic behavior, reaching a magnetization saturation value of 60.2 emu g-1. Due to the high recombination rate of electrons/holes, which is an intrinsic feature of ferrites, surface functionalization with silver was carried out to enhance charge separation. The results demonstrated a strong influence of adsorption and of the deposition of silver. Several optimization steps were performed during synthesis, allowing us to create efficient catalysts, as proved by the almost full removal of the dye malachite green attaining 95.0% (at a rate constant of 0.091 min-1) and 87.6% (at a rate constant of 0.017 min-1) using NPs obtained by the sol-gel and solvothermal methods, respectively. Adsorption in the dark accounted for 89.2% of the dye removal for nanoparticles prepared by sol-gel and 82.8% for the ones obtained by the solvothermal method. These results make mixed zinc/magnesium ferrites highly promising for potential industrial application in effluent photoremediation using visible light.

Tuning optical, magnetic, and electrical parameters of CuFe2O4 nanoparticles incorporated with GO and ZnO using a facile synthesis

Nano-ferrites, metal oxides, and carbon-based nanomaterials have been used frequently to enhance optical and magnetic prospects for latent applications. Copper ferrite/Graphene Oxide and Zinc Oxide (CuFe2O4/GO/ZnO) ternary nanocomposite synthesized by hydrothermal route showed dramatically good outcomes as the band gap energy value of synthesized nanocomposite approaches to 2.4 eV. Furthermore, the light absorbance of CuFe2O4 increases by adding ZnO and GO. The experimental data revealed the face-centered cubic structure (FCC) of pure spinal ferrite (CuFe2O4) nanoparticles even after adding ZnO and GO. The 2θ peak observed at 31.70° with (220) hkl planes indicates the successful addition of ZnO nanoparticles in CuFe2O4/GO nanocomposite. XRD graph, the absence of characteristic peaks of GO revealed the intercalation of CuFe2O4 nanoparticles with GO layers. In SEM images, agglomeration among CuFe2O4 nanoparticles is observed due to the magnetic interaction of nano-crystallite with a high surface-to-volume (S/V) ratio. VSM can be used to determine the magnetic properties of as-synthesized samples at moderate temperatures under 0–0.5 and ± 5 tesla. In CuFe2O4/GO/ZnO ternary nanocomposite, the saturation magnetization value reduces from 2.071 to 1.365 emu/g due to the addition of ZnO nanoparticles. The loops were narrowed showing a decrease in the coercive field with the addition of ZnO nanoparticles in CuFe2O4/GO ternary nanocomposite material. Moreover, the study of electrical properties of pure CuFe2O4 and CuFe2O4/GO/ZnO ternary nanocomposite revealed that the values of dielectric constant and tangent loss decrease at high frequencies owing to surface charge polarization and intrinsic dipole interactions. The study of the electrical properties of both pure CuFe2O4 and the CuFe2O4/GO/ZnO ternary nanocomposite reveals that the dielectric constant (ε’) and tangent loss (tanδ) exhibit a decreasing trend as the frequency increases. This behavior is attributed to surface charge polarization and intrinsic dipole interactions. At lower frequencies, both samples display elevated values for these properties, which stabilize as the frequency increases beyond 2 MHz. Notably, high AC conductivity is observed in both samples, attributed to increased capacitance and resistance.

Effects of La-Co Co-Substitution and Magnetic Field Pressing on the Structural and Magnetic Properties of SrM Hexaferrites

We carefully investigated the effects of La-Co co-substitution and magnetic field pressing (MFP) on the structural and magnetic properties of SrM hexaferrites. Samples composed of Sr1−xLaxFe12−xCoxO19 were sintered at 1230 °C for 2 h in air with sintering additives composed of 0.7 wt% CaCO3 and 0.7 wt% SiO2. A single M-type phase was confirmed to exist up to x = 0.3. Rietveld refinement revealed a slight decrease in lattice parameter a and the unit cell volume (Vcell) with an increasing x, while parameter c showed a significant decrease. The saturation magnetization (Ms) values increased from 70.90 to 72.40 emu/g with an increasing x from 0.0 to 0.15 and then decreased to 71.38 emu/g with further increasing of x to 0.3, while the anisotropy field (Ha) increased from 17.7 to 25.9 kOe, leading to a continuous increase in the intrinsic coercivity (Hci), from 3.52 to 5.00 kOe, respectively. Using the MFP process, the c-axis of M-type hexaferrite grains could be effectively aligned to the applied field direction, which significantly affected the microstructures and, thus, magnetic properties of samples. Unlike non-MFP samples, exhibiting a significant increase in the average grain size (davg) but almost unaltered average thickness (tavg) with an increasing x from 0.0 to 0.3, MFP-processed samples exhibited almost unaltered davg values but a continuous decrease in tavg. Consequently, the variation in remanent flux density (Br) versus x followed that of Ms versus x and thus exhibited the highest Br of 4.05 kG for x = 0.15, leading to the highest maximum energy product {(BH)max} of 3.62 MGOe. With an increasing x from 0.0 to 0.3, the Hci values continuously increased from 3.14 to 3.84 kOe mainly due to a continuous increase in Ha, although they were significantly lowered in comparison with those of non-MFP samples because of a large increase in Br for a given composition x. A higher Mr/Ms ratio always resulted in a larger (BH)max in our samples regardless of x. A careful comparison of the microstructures and magnetic properties between MFP and non-MFP samples provided valuable insights into a broad area of permanent magnet optimization.

Radiation-Induced Synthesis and Superparamagnetic Properties of Ferrite Fe3O4 Nanoparticles.

Ultra-small magnetic Fe3O4 nanoparticles are successfully synthesized in basic solutions by using the radiolytic method of the partial reduction in FeIII in the presence of poly-acrylate (PA), or by using the coprecipitation method of FeIII and FeII salts in the presence of PA. The optical, structural, and magnetic properties of the nanoparticles were examined using UV-Vis absorption spectroscopy, high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and SQUID magnetization measurements. The HRTEM and XRD analysis confirmed the formation of ultra-small magnetite nanoparticles in a spinel structure, with a smaller size for radiation-induced particles coated by PA (5.2 nm) than for coprecipitated PA-coated nanoparticles (11 nm). From magnetization measurements, it is shown that the nanoparticles are superparamagnetic at room temperature. The magnetization saturation value Ms = 50.1 A m2 kg-1 of radiation-induced nanoparticles at 60 kGy is higher than Ms = 18.2 A m2 kg-1 for coprecipitated nanoparticles. Both values are compared with nanoparticles coated with other stabilizers in the literature.

Effective Co2+ removal from aqueous solution and industrial wastewater using ZIF-7 and MnFe2O4-modified walnut shell biochar composite

In this study, we developed a novel magnetic composite of walnut shell biochar (WSB) and modified it with ZIF-7 for the purpose of removing Co2+ ions. We conducted a comprehensive evaluation of its performance in Co2+ removal, considering various factors such as contact time, temperature, adsorbent dose, pH, and initial Co2+ concentration. Utilizing response surface methodology-central composite design (RSM-CCD), we examined the interactions between these variables. The specific surface area and magnetic saturation value of the WSB/MnFe2O4/ZIF-7 composite were determined as 170.560 m2.g−1 and 23.469 emu.g−1, respectively. ANOVA analysis indicated that our model effectively captures the interactions between variables, with a high R2 value of 0.9982, explaining 99.82 % of the experimental data. Optimal conditions for maximum Co2+ adsorption efficiency (99.05 %) were identified as follows: a contact time of 44.82 min, pH of 6.04, adsorbent dose of 0.947 mg.L-1, temperature of 25.55 °C, and Co2+ concentration of 11.13 mg.g−1. Kinetic studies revealed that the Pseudo 2nd order kinetic model provided the best fit to the experimental data. The negative entropy parameter indicated a decrease in disorderliness during the adsorption process, while the exothermic nature of adsorption was confirmed by enthalpy values of −92.751 and −40.511 kJ.mol−1 for WSB/MnFe2O4/ZIF-7 and WSB, respectively. Furthermore, the Langmuir isotherm model demonstrated excellent fitting to the isotherm results, suggesting the dominance of homogeneous surfaces in adsorption. The maximum adsorption capacities for Co2+ using WSB/MnFe2O4/ZIF-7 and WSB were determined to be 29.26 and 22.39 mg.g−1, respectively. The WSB/MnFe2O4/ZIF-7 magnetic composite demonstrates promising potential for efficiently removing Co2+ from both natural water sources and industrial wastewater, highlighting its versatility and effectiveness in environmental remediation applications.

Efficient adsorptive removal of 2,4-dichlorophenoxyacetic acid (2,4-D) using biomass derived magnetic activated carbon nanocomposite in synthetic and simulated agricultural runoff water

This study focused on evaluating the efficacy of a magnetic activated carbon material (CPAC@Fe3O4) derived from pods of copper pod tree in adsorbing the toxic herbicide, 2,4- (2,4-D) from aqueous solutions. The synthesized CPAC@Fe3O4 adsorbent, underwent various characterization techniques. FESEM images indicated a rough surface, incorporating iron oxide nanoparticles, while EDS analysis confirmed the presence of elements like Fe, O, and C. Notably, the CPAC@Fe3O4 exhibited high surface area (749.10 m2/g) and pore volume (0.5351 cm³/g), confirming its mesoporous nature. XRD investigations identified distinct signals associated with graphitic carbon and magnetite nanoparticles, while VSM analysis verified its magnetic properties with a high magnetic saturation value (2.72 emu/g). The adsorption process was exothermic, with a decrease in adsorption capacity at higher temperatures. Freundlich isotherm provided the best fit for the adsorption, and the pseudo-second-order equation effectively described the kinetics. Remarkably, the maximum adsorption capacity ranged from 246.43 to 261.03 mg/g, surpassing previously reported values. The ΔH° value (−8.67 kJ/mol) suggested a physisorption mechanism, and the negative ΔG° values established the spontaneous nature. Furthermore, the synthesized adsorbent demonstrated exceptional reusability, allowing for up to five cycles of adsorption-desorption operations. When applied to simulated agricultural runoff, CPAC@Fe3O4 showcased a significant adsorption capacity of 160.71 mg/g for 50 mg/L 2,4-D, using a 0.2 g/L dosage at pH 2. This study showcased the transformation of copper pod biomass into a valuable magnetic nanoadsorbent capable of efficiently eliminating the noxious 2,4-D pollutant from aqueous environments.

Synthesis and characterization of magnetic molecularly imprinted polymers for the rapid and selective determination of clofazimine in blood plasma samples

Clofazimine (CLF) is a riminophenazine derivative and a new therapeutic option with high efficacy for patients with rifampicin-resistant tuberculosis (TB). The blood levels of CLF are low and suboptimal, so therapeutic drug monitoring is required. Prior to this study, there were no molecular imprinting–based solid phase extraction (SPE) sorbents that could be used to determine the blood CLF levels. Hence, we prepared a magnetic molecularly imprinted polymer (MMIPs) to capture CLF. We employed computational selection of a functional monomer and crosslinker and confirmed these selections based on the association constant (Ka) and a Job plot. We synthesised MMIPs with two surface modifiers and characterized the polymers. Our computational analysis based on the bond energy revealed that methyl methacrylate (MMA) was the most suitable functional monomer at a CLF-to-MMA molar ratio of 1:4. Based on the bond energy, the most suitable crosslinker was trimethylolpropane trimethacrylate (TRIM) at a CLF-to-TRIM molar ratio of 1:1. We determined the Ka of MMA and TRIM in different solvents. Isopropanol produced the highest Ka. The Job plot showed that a template-to-MMA-to-TRIM molar ratio of 1:4:20 was optimal to synthesize imprinted polymer in isopropanol. We prepared MMIPs using two different modifiers, namely aminopropyltrimethoxysilane (APTES) and oleic acid (OA), using the ratio determined from the Job plot. Physical characteristic tests carried out using FT-IR, SEM-EDS, PSA, BET and VSM, showed that the synthesis was success with a spherical and uniform agglomeration of particles, also a flat surface with many holes with a particle size of MMIP-APTES and MMIP-OA respectively 0.14 μm and 0.28 μm, showed a surface area for MMIP-APTES is 2874.51 m2/g and MMIP-OA 2913.07 m2/g, exhibiting superparamagnetic properties with a saturation magnetization value of MMIP-APTES 21.1 emu/g−1 and MMIP-OA 49.9 emu/g−1. Adsorption capacity result showed that MMIP-OA fits well with the Langmuir model, while MMIP-APTES fits better with the Freundlich. Application of MMIP-SPE (Magnetic Molecular Imprinted Polymer-Solid Phase Extraction) APTES resulted 92.3 ± 6.1 % and MMIP-SPE-OA 51.5 ± 8.1 % for recovering CLF in blood. The result of selectivity test also showed that MMIP-SPE-APTES is better than MMIP-SPE-OA and selectively recover CLF from human blood plasma existed together with other TB-Drugs. The study result shows that MMIPs with APTES modification can be used for CLF determination in human blood plasma.

Development of a magnetite nanocomposite based on expanded graphite/chitosan for efficient removal of brilliant green dye from aqueous solutions

ABSTRACT In this research, to develop an efficient and magnetic graphite-based nanocomposite (Fe3O4/EG-chitosan), the natural flake graphite was first expanded to improve its active surface area. The expanded graphite (EG) was then functionalized and magnetized with chitosan and Fe3O4 nanoparticles to increase its adsorption performance. Structure of EG/chitosan and nanocomposite Fe3O4/EG-chitosan were determined and confirmed by FT-IR, XRD, EDX, FESEM, VSM, zeta potential measurement and BET surface area measurements. The surface area of EG was improved from 10.13 to 83.08 m2/g after the functionalization of it using chitosan. Fe3O4/EG-chitosan exhibited a lower magnetization saturation value (30.9 emu/g) in compared with pure Fe3O4 NPs (60.2 emu/g). The fabricated nanocomposite was then applied to adsorb BG dye from aqueous media. The optimal removal of 98% BG dye was achieved at pH 8.0, adsorbent dosage 0.04 g, initial concentration 50 ppm, and temperature 293 K. The adsorption of BG is described well with the pseudo-second order kinetic model and the Freundlich isotherm model. The results also showed that the maximum adsorption capacity of BG dye was 21.8 mg/g using the Langmuir isotherm model. In addition, after 6 adsorption-desorption cycles, the adsorption capacity of the developed Fe3O4/EXG-chitosan toward BG remains high (90%).

Thermal-responsive β-cyclodextrin-based magnetic hydrogel as a de novo nanomedicine for chemo/hyperthermia treatment of cancerous cells

A novel thermal-responsive β-cyclodextrin-based magnetic hydrogel [β-cyclodextrin-graft-poly(N-isopropylacrylamide)/Fe3O4 (β-CD-g-PNIPAAm/Fe3O4)] was fabricated as a novel nanomedicine for chemo/hyperthermia treatment of cancer cells. Firstly, β-CD was modified by maleic anhydride (MA) followed by copolymerization with NIPAAm monomer and thiol-end capped Fe3O4 nanoparticles (NPs) in the presence of a crosslinker through acrylamide–thiol polymerization system to afford a magnetic hydrogel. The saturation magnetization (δs) value for developed hydrogel was determined to be 8.2 emu g−1. The hydrogel was physically loaded with an anticancer agent, doxorubicin hydrochloride (Dox). The encapsulation efficiency (EE) of drug into the hydrogel was obtained as 73 %. The system represented acceptable thermal-triggered drug release behavior that best fitted with Higuchi model, demonstrating the release of drug is mostly controlled by diffusion mechanism. The anticancer performance of the β-CD-g-PNIPAAm/Fe3O4-Dox was evaluated using MCF7 cells by MTT-assay. In addition, flow cytometry analyses showed considerable cellular uptake of Dox in the cells treated with β-CD-g-PNIPAAm/Fe3O4-Dox (∼70 %) compared to free Dox (∼28 %). As results, in time period of 48 h by combination of chemo- and hyperthermia-therapies, the developed system displayed greater anticancer efficiency than the free Dox.

Antiepileptic drug-loaded and multifunctional iron oxide@silica@gelatin nanoparticles for acid-triggered drug delivery

The current study developed an innovative design for the production of smart multifunctional core-double shell superparamagnetic nanoparticles (NPs) with a focus on the development of a pH-responsive drug delivery system tailored for the controlled release of Phenytoin, accompanied by real-time monitoring capabilities. In this regard, the ultra-small superparamagnetic iron oxide@silica NPs (IO@Si MNPs) were synthesized and then coated with a layer of gelatin containing Phenytoin as an antiepileptic drug. The precise saturation magnetization value for the resultant NPs was established at 26 emu g-1. The polymeric shell showed a pH-sensitive behavior with the capacity to regulate the release of encapsulated drug under neutral pH conditions, simultaneously, releasing more amount of the drug in a simulated tumorous-epileptic acidic condition. The NPs showed an average size of 41.04 nm, which is in the desired size range facilitating entry through the blood–brain barrier. The values of drug loading and encapsulation efficiency were determined to be 2.01 and 10.05%, respectively. Moreover, kinetic studies revealed a Fickian diffusion process of Phenytoin release, and diffusional exponent values based on the Korsmeyer-Peppas equation were achieved at pH 7.4 and pH 6.3. The synthesized NPs did not show any cytotoxicity. Consequently, this new design offers a faster release of PHT at the site of a tumor in response to a change in pH, which is essential to prevent epileptic attacks.

Investigation of Crystallographic, Morphological, Magnetic and Electrochemical Properties of La‐Doped Cu‐CoFe2O4 Spinel Ferrites

AbstractThis research presents the successful synthesis of Cu0.79Co0.21LaxFe2‐xO4 (0.0 ≤ x ≤ 0.8) (spinel ferrite) nanoparticles via the sol‐gel auto combustion technique, with varying La3+ dopant concentrations. In this study, the estimated crystallite size (D) is found to be in the range of (27.92–40.90) nm. The microstructural parameter determination in XRD data is improved using Rietveld refinement. Fourier Transform Infrared Spectroscopy (FTIR) spectra exhibit two distinct metal stretching vibrational bands within (400–600) cm−1 range, a characteristic fingerprint region for all ferrites. Field Emission Scanning Electron Microscopy (FESEM) analysis reveals the agglomeration of particles due to magnetic interactions and non‐uniform distribution of average particle sizes ranging from (1.06–1.87) µm. Energy Dispersive X‐Ray Analysis (EDX) validates the chemical composition's accuracy. Owing to the dilution effect resulting from the introduction of non‐magnetic La3+ ions into the ferrite structure, there is a reduction in the saturation magnetization value, decreasing from 37.28 to 6.24 emu g−1 in the Vibrating Sample Magnetometery (VSM) study. The electrochemical analysis reveals the impressive electrochemical characteristics of the newly developed ferrites, highlighting a remarkable specific capacitance of 270.0 F g−1. This finding positions them as highly promising contenders for a wide range of energy storage supercapacitor applications.

Fabrication and characterization of rubidium ferrites by the solution‐based combustion method using diverse organic fuels

Fabrication and characterization of rubidium ferrites by the solution‐based combustion method using diverse organic fuels

Effect of grain size on the dielectric and magnetic properties of YFeO3 ceramics densified by microwave sintering and spark plasma sintering from powders synthesized via reverse chemical co-precipitation

YFeO3 (YFO) ceramics were synthesized by reverse co-precipitation at different pH values followed by microwave sintering (MS) and spark plasma sintering (SPS) techniques. Also, the effect of the grain size on the magnetic and dielectric properties of the sintered ceramics was examined using various characterization methods. Moreover, FESEM micrographs showed that the particle size of the calcined samples has declined by increasing the pH value. Furthermore, the magnetization curves exhibited weak ferromagnetic behavior in the pre-sintered powder samples. Besides, the Ms value was enhanced from 1.26emu/g to 2.3emu/g by an increase in pH from 8.5 to 10.5 owing to reducing the particle size and subsequently raising the amount of uncompensated surface spins. Furthermore, the powder samples showed an increase in the Hc and Mr values from 15Oe to 28Oe and 0.127emu/g to 0.296emu/g, respectively, with a reduction in particle size from 0.632 μm to 0.272 μm. Additionally, the specimens processed through the sintering techniques demonstrated a remarkable reduction in magnetic characteristics. Therefore, a decrease in magnetic saturation values from 2.3emu/g to 0.43emu/g for the MS sample and to 0.17emu/g for the SPS specimen was attributed to a marked reduction in the amount of free surfaces and subsequently uncompensated surface spins. At last, the observed dielectric characteristics of all the sintered pellets had a common dielectric behavior. This signifies that by increasing the frequency the ε′ and tanδ decline at lower frequencies and become frequency-independent at higher frequencies based upon the Maxwell-Wagner polarization theory. On the other hand, the ε′ value for the SPS sample produced at pH = 10.5 underwent a decline of 2.5 times at the low frequency of 200 Hz compared to the MS one due to the significant decrement of the grain boundaries on account of the coarsening of grains.

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.

Facile synthesis of silver nanoparticles loaded spent cathodic Lithium-Ion battery components for enhanced bifunctional photocatalysis: Investigating the influence of magnetic properties

Due to resource depletion and environmental concerns regarding battery disposal, it is becoming more essential to recycle valuable metals from wasted lithium-ion batteries (LIBs). A novel approach is proposed in this study for the efficient bifunctional photocatalysis of LIBs components by integrating AgNPs in an environmentally sustainable manner via a sustainable hydrothermal process. The HRTEM and image mapping reveal a carbon matrix (C/Li3Fe5O8/Ag) with a dispersed arrangement of AgNPs (5–10 wt%). By acting as a reducing agent, graphite plays a crucial role in the transformation of Ag+ ions into AgNPs. The homogenous distribution of Ag NPs observed in the high-resolution TEM images further supports the role of graphite in the modification and decoration of Ag NPs onto the surface of the extracted spent cathode sample. The detection of a spot matching the (200) plane of Ag in the selected area electron diffraction (SAED) measurements confirms the successful formation of AgNPs. Additionally, the presence of a ring corresponding to the (110) plane of graphite in the SAED measurements suggests the coexistence of graphite with AgNPs in the composite heterostructures. The nitrogen adsorption isotherm analysis was conducted to explore the physical properties of the AgNPs@LIBs nanocomposite, providing valuable insights into its pore size distribution and Brunauer–Emmett–Teller (BET) surface area. The nanocomposites exhibited paramagnetic behavior, as revealed by vibrational sample magnetometer (VSM) measurements, with saturation magnetization values ranging from 76.3 × 10−3 to 36.13 × 10−3 emu/g. The study involved the photodegradation of oxytetracycline (OTC), a representative pharmaceutical pollutant, along with an investigation into the potential of Cr(VI) reduction. Under optimal component ratios, a significant improvement in pollutant removal was achieved under UV radiation, reaching up to 75 % for OTC and 80 % for Cr(VI), highlighting the efficiency of the process.

COMPARATIVE STUDY OF MODELS AND A NEW MODELOF FERROFLUID VISCOSITY UNDER MAGNETIC FIELDSAND VARIOUS TEMPERATURES

Ferrofluid is a substance with a controllable viscosity that is used in various systems for dispersing mechanicalenergy, such as brakes or vibration dampers. It is also used in seals or loudspeakers. An increase in themagnetic field affects the formation of particle structures inside the carrier fluid, which increases internalfriction. Existing mathematical models that describe the increase in viscosity do not provide satisfactoryresults for commercial and undiluted ferrofluids. In this study, we measured viscosity, which refers to theincreased resistance a magnetic fluid creates when it flows under shear. Various synthetic oil-based ferrofluidswith known saturation magnetization values and different particle distributions were selected for the study.The temperature range of 25–80C and the value of the shear rate of 100 s-1 were taken into account. The aimof the study is to compare existing mathematical models with experimental results and to propose a model thatbest describes the effect of the magnetic field on the increase in viscosity of the fluids studied. The proposedmodel is based on dividing the particle distribution into two fractions and applying a correction factor. Theresults showed that the difference in theoretical and experimental values does not exceed 6.5%. Research andresults have potential applications in the design and development of synthetic oil-based ferrofluid applicationswhere significant temperature changes occur.

Effect of divalent ion of strontium substitution on the structural, optical, magnetic and blood compatibility studies in cobalt ferrite

This study investigates the effects of Sr2+ substitution on the structural, morphological, and magnetic properties of magnetic cobalt ferrite (CoFe2O4). Through sol–gel auto-combustion synthesis, Sr2+ was substituted into Co-spinel ferrites (Co1-xSrxFe2O4, where x = 0.0, 0.25, 0.5, 0.75, 1.0). SEM analysis revealed spherical grains with an average size of 54.4 nm. XRD analysis indicated systematic changes in crystallographic parameters and the formation of secondary phases with Sr-substitution. While the crystal size for CoFe2O4 was calculated as 262 nm, this value was determined as 18 nm for Co0.25Sr0.75Fe2O4. FT-IR results suggested increased force constants of octahedral and tetrahedral bonds with higher Sr content, with main vibration bands at 423.6 and 606 cm−1. M-H curves exhibited S-shaped behavior, indicating drastic magnetic property changes with Sr2+ substitution. Coercivity field (Hc), saturation magnetization (M S ), and remanent magnetization (M r ) values ranged from 1447.8–545.4 Oe, 58.8-14 emu g−1, and 36.8-7.6 emu g−1, respectively. Blood compatibility experiments highlighted Co0.75Sr0.25Fe2O4 nanoparticles with significantly low hemolysis rates compared to other concentrations.

Magnetic properties and microstructure of Ce and Zr synergetic stabilizing Ti-lean SmFe12-based strip-casting flakes

Recently ThMn12-type samarium iron alloys have been promising materials for permanent magnets. Due to the high abundance and low cost, Ce as a possible stabilizer can be introduced into ThMn12-type alloys. The effect of Ce doping on the magnetic moment and phase stability in Ti-lean (Ce,Sm,Zr)(Fe,Co,Ti)12 compounds were predicted by the first-principles calculations. The CexSm0.8-xZr0.2(Fe0.8Co0.2)11.5Ti0.5 (x = 0–0.8) alloys with ThMn12 structure were produced by strip-casting into flakes by a wheel speed of 1.5 m/s and annealed at 1000 °C for 24 h. The Ce0.8Zr0.2(Fe0.8Co0.2)11.5Ti0.5 annealed flake shows a high saturation magnetization value of 13.6 kGs at room temperature. With the increase of Ce substitution in the annealed flakes, the content of α-(Fe,Co,Ti) phase decreases and the saturation magnetization increases. The 1:12 phase and the 1:9 phase have an orientation relationship that can be expressed as [0 0 –1]1:12//[100]1:9 and (020)1:12//(010)1:9. Besides, annealing process promotes the formation of 1:12 phase transformed from 1:9 phase. Coercivity is expected to be improved by obtaining uniform microstructure and suppressing the formation of soft α-(Fe,Co,Ti) phase in the ThMn12-based alloys.