Exhibited Saturation Magnetization Research Articles

Unveiling electronic structure and magnetic properties of AFe2O4 (A = Co, Ni, Zn, and Mg): Synergizing experimentation with DFT investigation

This study presents the synthesis of nano-crystalline spinel ferrites AFe2O4 (A = Co2+, Ni+2, Zn+2, and Mg+2), through the sol-gel method, yielding crystallite sizes ranging from 12 to 28 nm. The variation in IR and Raman spectra due to M-O-M bonding supports the variation in lattice parameters. The magnetization measurements revealed that CoFe2O4 has a high saturation magnetization of ∼55 emu/g and coercivity of ∼1350 Oe, while ZnFe2O4 exhibited saturation magnetization value of ∼8 emu/g and coercivity of ∼16 Oe. In addition, the electronic structure calculated using DFT, which corroborated the antiparallel alignment of Fe ions in the tetrahedral and octahedral sites, validating the measured magnetic moments. Notably, the CoFe2O4 ferrite exhibited a higher squareness ratio than other ferrites, signifying its suitability as a magnetic material for audio-video recording.

Effect of Gd[formula omitted]O[formula omitted] on physical, structural, optical and magnetic characteristics of vanadium containing borosilicate glasses

This study reports the effect of Gd2O3 on physical, structural, optical, and magnetic properties of 40SiO2−40B2O3−10V2O5−(10−x)Fe2O3−xGd2O3 (x = 2, 4, and 6 mol%) glasses. The structural, optical, and magnetic characteristics of the as-quenched samples were obtained using various experimental techniques. The optical band gap was decreased with the concentration of Gd2O3 in place of Fe2O3 in glass composition i.e., 4.03 to 3.81 eV whereas, the theoretical optical basicity and oxide ion polarizability increase. The magnetic nature of the as-prepared glasses is soft and exhibited saturation magnetization in the range of 2.1 to 2.6 emu/g with a critical magnetic field of 122 to 138 Oe. With a higher critical magnetic field, the inclusion of Gd2O3 reduces saturation magnetization. This phenomenon could be related to the change in local structure due to glass network modification by Gd2O3 and the presence of some nanocrystalline or microcrystalline phase in a glass matrix. The developed glass has the potential to be used as a thermoseed for treating cancer patients with hyperthermia.

First-principles calculations to investigate Structural, mechanical, electronic, magnetic and thermoelectric properties of MRh2O4 (M = Mg, Mn, Cd) spinel oxides

Structural, mechanical, magnetic, electronic and thermoelectric properties of MRh2O4 (M = Mg, Mn, Cd) spinel oxides are studied through first-principles calculations. Calculations of structural and elastic stiffness constants (Cij’s) show that the MRh2O4 oxides are stable structurally and mechanically. Elastomechanical results show that the CdRh2O4 is ductile, MnRh2O4 is brittle, while MgRh2O4 lies on the borderline differentiating the ductile and brittle character. MnRh2O4 has high bulk modulus and high Young’s modulus which indicate its ability to resist plastic deformation. MnRh2O4 spinel oxide bears the highest values of Debye temperature (TD = 634.4 K) and melting temperature (Tm = 3530.4 K) among the MRh2O4 (M = Mg, Mn, Cd) oxides. Band structure calculations and density of states spectra indicate the p-type semiconducting nature of MRh2O4 (M = Mg, Mn, Cd) oxides. Spin-polarized electronic structure of CdRh2O4 show 100 % spin-polarized behavior, while MgRh2O4 and MnRh2O4 oxides show 0.12 % and 0.29 % spin-polarization, respectively. MnRh2O4 exhibits saturation magnetization Ms = 172 emu/g and total magnetic moment mtot = 9.99 µB/f.u. Temperature dependent thermoelectric properties (thermal conductivity, electrical conductivity, Seebeck coefficient, Hall coefficient, power factor and figure of merit) are also studied for MRh2O4 oxides. Calculated thermoelectric properties of MRh2O4 (M = Mg, Mn, Cd) oxides show that these oxides are promising for applications as novel thermoelectric materials.

Magnetic behavior of in-situ synthesized iron oxides in mesoporous graphite matrix

Microwave irradiation-induced synthesis of nanomaterials offers large-scale fabrication by in-situ decomposition of organo-metallic complexes through a variety of solvents. But there are limited attempts to fabricate them using a solvent-free environment. In the present work, we have reported successfully pyrolysis of ferric acetylacetonate complex to produce iron oxide using mesoporous graphite (MG) under microwave irradiation without assistance of solvent. The two-step synthesis consists of the preparation of mesoporous graphite using mild conditions of Hummer’s method and its composite with ferric oxides was done by heating mesoporous graphite with ferric acetylacetonate in a domestic microwave oven. The preliminary magnetic behavior of in-situ synthesized mesoporous graphite (MG) composite with mixed ferric oxides was studied. The room temperature magnetic behavior of the as-prepared composite exhibited saturation magnetization of 11.27 emu-g-1. The Formation of α-Fe2O3 and γ-Fe2O3 along with particle size distribution and dispersion was evaluated through detailed structural characterization. Our study shows mesoporous graphite acts not only as a substrate but also as a microwave receptor. This can extend the avenues of existing carbonaceous materials in converting microwave energy into thermal energy.

Impact of Co-doped NiFe2O4 (CoxNi1−xFe2O4) nanostructures prepared by co-precipitation route on the structural, morphological, surface, and magnetic properties

The excellent magnetic properties of spinel ferrite-based materials are preferably utilized in magnetic storage devices, and recording media. The magnetic properties of cobalt-doped nickel ferrite (Cox Ni1-xFe2O4) nanoparticles (NPs) were successfully investigated. A series of cobalt (Co)-doped nickel ferrite Cox Ni1-xFe2O4 NPs (x = 0.6, 0.7, 0.8, 0.9,1.0) were synthesized by the sol-gel method auto-combustion (SGAC) route. The crystallite sizes of the prepared CoxNi1−xFe2O4 NPs were found to be 23.5 ± 0.4, 25.3 ± 0.3, 25.0 ± 0.6, 29.5 ± 0.3, and 12.7 ± 0.3 nm for x = 0.6, 0.7, 0.8, 0.9, and 1.0, respectively, using X-ray diffraction (XRD) patterns. The random-shaped morphology with particle sizes was found to be 16.4 ± 0.8, 12.6 ± 0.1, 15.4 ± 0.7, 12.5 ± 0.2, and 11.9 ± 0.4 nm for CoxNi1−xFe2O4 (x = 0.6, 0.7, 0.8, 0.9, and 1.0), respectively, using high-resolution transmission electron microscopy (HRTEM). Tauc’s plot spectra of CoxNi1−xFe2O4 NPs showed that the direct band (2.01–2.42 eV) and indirect band gaps (0.86–1.16 eV) were tuned with Co2+ concentrations. The obtained binding energies (BEs) observed at (780–801 eV) for Co2+ and Co3+ions, (855–879 eV) for Ni2+ and Ni3+ ions, (710–760 eV) for Fe3+ and Fe2+ ions, and (529–531 eV) for O2- ions, respectively in CoxNi1−xFe2O4 NPs were confirmed by X-ray photoelectron spectroscopy (XPS). RT-dependent DC magnetization measurements exhibited saturation magnetization (45.28, 37.34, 33.32, 33.93, and 52.57 emu/g), coercivity (1090, 1160, 689, 507, and 377 Oe), retentivity (13.29, 12.86, 11.37, 8.10, and 10.18 emu/g), and magnetic anisotropy (4.834 ×106, 4.315 ×106, 4.037 ×106, 4.206 ×106, and 7.578 ×106 erg/cm3) for CoxNi1-xFe2O4 NPs (x = 0.6, 0.7, 0.8, 0.9, and 1.0), respectively. The improved magneto-crystalline anisotropy and decreased spin canting effect/ spin disorder for CoxNi1−xFe2O4 NPs indicated that the current research work can be suitable for magnetic storage devices and recording media.

High reusability of green-synthesized Fe3O4/TiO2 photocatalyst nanoparticles for efficient degradation of methylene blue dye

This study investigates photocatalytic degradation performance of Fe 3 O 4 /TiO 2 nanoparticles (NPs) green-synthesized using Moringa oleifera leaf extract. A coprecipitation synthesis method was successfully used to synthesize NPs of various concentrations and the magnetic properties of the photocatalyst was further explored so that it could be reused. X-ray diffraction and selected area electron diffraction showed that TiO 2 has a tetragonal structure and Fe 3 O 4 has an inverse spinel cubic structure. The prepared transmission electron microscopy image of Fe 3 O 4 /TiO 2 showed that it was almost spherical, not uniform, and slightly dispersed under agglomerated conditions due to the presence of a TiO 2 boundary. Besides, the chemical elements are confirmed by energy-dispersive X-ray spectroscopy . Fourier-transform infrared spectra showed functional groups namely C–H, C=O, C=C, and C–N which indicating successful green synthesis. In addition, the presence of Fe–O functional groups at 551.8–620.3 cm −1 and Ti-O at 400–600 cm −1 also suggests the formation of NPs. A vibrating sample magnetometer showed that the Fe 3 O 4 /TiO 2 NPs exhibited saturation magnetization in the range of 11.15–30.38 emu/g, with a coercivity value of approximately 55 Oe. The degradation efficiency of methylene blue (MB) was optimal for Fe 3 O 4 :TiO 2 at a concentration of 1:7 which reached 99.9% degradation for two hours for uptake every 20 minutes. Owing to the magnetic potential of the synthesized NPs, they could be recycled up to four times without significant loss of activity. Therefore, green synthesis of Fe 3 O 4 /TiO 2 NPs is promising for effective and efficient removal of organic pollutants in various environment-related applications. • Fe3O4/TiO2 NPs were synthesized using coprecipitation method with MO extract • Green-synthesized Fe3O4/TiO2 NPs have superior photocatalytic activity up to 99.9% • kapp value between the theoretical model and the experimental data has a good match • After 4 repetitions, the photocatalyst showed excellent stability and reusability • A conceivable photocatalytic mechanism has been proposed

Annealing modulated magnetism in double-perovskite PrBaMnFeO5.5+δ ferromagnetic insulator

Double-perovskite oxides are known to exhibit important electronic, magnetic, and electrochemical properties, including metal-insulator transition, colossal magnetoresistance, and excellent mixed conductivity. Here, single-crystalline PrBaMnFeO5.5+δ thin films were epitaxially grown and sensitively tailored to a tunable ferromagnetic state by post-annealing. The drastically tunable ferromagnetism is attributed to the detailed atomic microstructures, localized oxygen vacancy distribution, and exchange interactions between Mn and Fe ions with different valences. The as-grown PrBaMnFeO5.5+δ epitaxial film exhibits saturation magnetization twice that of undoped PrBaMn2O5.5+δ, probably owing to the synergistic reaction of Mn3+–O–Mn4+ double exchange and Mn3+–O–Fe3+ superexchange interactions. These findings suggest that the PrBaMnFeO5.5+δ double-perovskite film can be an effective ferromagnetic insulator with the strategic magnetic properties of complex manganite oxides tuned by chemical strains.

Synthesis, thermal stability, magnetic properties, and microwave absorption applications of CoNi-C core-shell nanoparticles with tunable Co/Ni molar ratio

Magnetic alloy-C core-shell nanoparticles with tunable elemental components are highly expected for their controllable magnetic, catalytic, and electromagnetic properties, and high air stability. Here we present a simple one-step metal organic chemical vapor deposition for the synthesis of CoNi-C core-shell nanoparticles with tunable Co/Ni molar ratio. The as-synthesized nanoparticles have core sizes of 5–50 nm, shell thicknesses of ~5 nm, and tunable Co/Ni molar ratio determined by the molar ratio of Co(acac)3/Ni(acac)2 used in the precursor. The core-shell nanoparticles are very stable in ambient atmosphere at the temperature below 200 °C, and exhibit a slight oxidation in the temperature range of 200–400 °C. The core-shell nanoparticles with Co/Ni molar ratios of 1.27:1, 0.64:1, and 0.30:1 exhibit saturation magnetization values of 41, 31, and 24 emu/g, and coercivity values of 483, 346, and 362 Oe, respectively. It is demonstrated that the microwave absorption parameters of the as-synthesized nanoparticles can be tuned by the Co/Ni molar ratio, which provides a practical strategy to regulate the microwave absorption properties of nanostructured absorbers.

One-spot fabrication and in-vivo toxicity evaluation of core-shell magnetic nanoparticles

This research, for the first time, report the synthesis of core-shell magnetic nanoparticles (NPs) consisting poly acrylic acid (PAA) coated cobalt ferrite (CF) using a simple co-precipitation route. Nanocrystalline PAA@CF-NPs, particle size of 9.2 nm, exhibited saturation magnetization as 28.9 emu/g, remnant magnetization as 8.37 emu/g, and coercivity as 543 Oe. Keeping biomedical applications into consideration, PAA@CF-NPs were further analysed to evaluate antimicrobial performance against Gram positive (Staphylococcus aureus and Bacillus subtilis) and Gram negative (Pseudomonas aeruginosa and Escherichia coli) bacteria, and biocompatibility with reference to activated splenic cells. The PAA@CF-NPs were viable to the normal splenic cells (up to 1000 μg/ml) and do not affect the ability of fast dividing ability of the cells (activated splenic cells). An optimized dose of PAA@CF-NPs was intramuscularly administrated (100 μg/ml) into Albino mice to evaluate acute toxicity. The results of these studies suggest that injected PAA@CF-NPs do not affect vital organs mainly including liver and kidneys that confirmed the heptic/renal biocompatibility. The outcomes of this research project such developed nano-system for biomedical applications, mainly for magnetically guided drug delivery and image guided therapies development. However, to support the proposed claims, extended in-vivo studies are required to explore bio-distribution, chronic toxicity, and homeostatic conditions.

Aminodextran Coated CoFe2O4 Nanoparticles for Combined Magnetic Resonance Imaging and Hyperthermia.

Aminodextran (AMD) coated magnetic cobalt ferrite nanoparticles are synthesized via electrostatic adsorption of aminodextran onto magnetic nanoparticles and their potential theranostic application is evaluated. The uncoated and aminodextran-coated nanoparticles are characterized to determine their hydrodynamic size, morphology, chemical composition, zeta potential and magnetization. The aminodextran containing cobalt ferrite nanoparticles of nanometer size are positively charged in the pH range from 3 to 9 and exhibit saturation magnetization of 50 emu/g. The magnetic resonance imaging (MRI) indicates capability for diagnostics and a reduction in intensity with an increase in nanoparticle amount. The hyperthermia capability of the prepared particles shows their potential to generate suitable local heat for therapeutic purposes. There is a rise of 7 °C and 9 °C at 327 kHz and 981 kHz respectively and specific absorption rates (SAR) of aminodextran-coated nanoparticles are calculated to be 259 W/g and 518 W/g at the given frequencies larger than uncoated nanoparticles (0.02 W/g). The development of novel aminodextran coated magnetic cobalt ferrite nanoparticles has significant potential to enable and improve personalized therapy regimens, targeted cancer therapies and ultimately to overcome the prevalence of nonessential and overdosing of healthy tissues and organs.

Preparation and characteristics of Co nanoporous magnetic materials synthesized by a template-free method

We report a template-free hydrogen reduction approach to prepare cobalt nanoporous magnetic materials with various morphologies employing Co3O4 as precursors, which were obtained by thermal-decomposing CoCO3 intermediates. The kinetic control of experimental parameters of synthetic CoCO3 intermediates by a facile solvent-thermal route can be an effective strategy to tune the morphology of Co nanoporous structures. The microstructures, crystal structures or thermal characteristics of products at different stages were investigated to reveal the formation mechanism of the Co nanoporous structures. Magnetic measurement showed that the Co nanoporous structures with rhomb-like and prism-like morphology exhibited saturation magnetization (Ms) of 149.2 emu/g and 141.8 emu/g, and coercivity (Hcj) of 508.4 Oe and 554.9 Oe, respectively. The as-prepared Co ferromagnetic materials exhibited remarkably high coercivity values mainly due to the three dimensional nanoporous structures.

Supermagnetic cellulose nanocrystal hybrids reinforced PHBV nanocomposites with high sensitivity to intelligently detect water vapor

In this work, cellulose nanocrystals (CNCs) incorporated with supermagnetic iron oxide nanoparticles (Fe3O4 NPs) as (MCNC) hybrids by the co-precipitation method have developed. High-performance nanocomposite films consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) and MCNC hybrids have prepared through a simple solution casting method. The addition of CNCs in MCNC-5% hybrids improved the surface hydrophilicity of PHBV, and displayed a reduction in water vapor permeability by 68.1 %, compared with pristine PHBV. The results prove that the addition of MCNC hybrids can be acted like a sensor to detect voltage change of the nanocomposites as functions of water vapor. The existence of CNCs in the MCNC-5% hybrids caused an increase in tensile strength and Young’s modulus by 74.6 % and 120.2 %, respectively. The addition of CNCs could enhance cell-matrix interactions and thus cytocompatibility of PHBV nanocomposites. The PHBV/MCNC-5% exhibited saturation magnetization (Ms) values of 1.5 emu g−1 and displayed almost a regular and operative voltage response signal with real-time monitoring of water vapor. This work provides sustainable smart packaging materials with high sensitivity for water vapor and excellent biocompatibility.

Fe3O4 nanoparticles decorated multi-walled carbon nanotubes based magnetic nanofluid for heat transfer application

The synthesis of magnetic multi-walled carbon nanotubes (MWCNTs)-iron oxide (Fe3O4) nanocomposite (NC) provides many interesting traits in individual moieties unfolding new opportunities for a wide range of applications. Several preparation techniques have been employed in the recent past to synthesizeMWCNTs-Fe3O4 NCs. Herein, we report the synthesis of Fe3O4 nanoparticles (NPs) decorated MWCNTs NC for heat transfer application. The NC was synthesized via co-precipitation method with a high-quality yield. The magnetic characterization of the as-synthesized NC exhibited saturation magnetization and was found to be 34.86 emu/g. Finally, magnetic nanofluids were prepared by dispersing different amounts of the as-synthesized NC into mineral oil, which is rarely reported. A ~50% enhancement in the thermal conductivity of the magnetic nanofluid was observed with loading of ~0.5 g/L of NC, which is better than the results reported so far for various nanofluids.

High-$Q$ On-Chip $C$ -Band Inductor With a Nanocrystalline MnZn-Ferrite Film Core

The miniaturized on-chip inductor was developed for the $C$ -band (4–8 GHz) and beyond, to meet the requirements of upcoming 5G technology devices. This paper presents the deposition of nanocrystalline manganese–zinc ferrite (Mn x Zn1– x Fe2O4; $x = 0.5$ ) thin films in a CMOS-compatible way on top of an on-chip inductor structure. A 200 nm-thick film was conformally deposited directly on a foundry-fabricated inductor after removing the top passivation layer by dry etching. The $Q$ -factor is found to be enhanced by 10% at the upper end (8 GHz) of the $C$ -band, while the self-resonance frequency of the inductor is up-shifted to 21 from 16 GHz. The film on a dummy Si (100) substrate exhibits saturation magnetization ( $4\pi \text{M}_{S}= 160$ mT) and coercivity ( $\text{H}_{C}= 3.5$ mT) much lower than for the bulk material. The film was deposited by a rapid ( $C$ -band inductor with a manganese–zinc ferrite film core.

Sono-assisted rapid adsorption of anionic dye onto magnetic CaFe2O4/MnFe2O4 nanocomposite from aqua matrix

In this research the proficiency of a novel magnetic calcium ferrite and manganese ferrite nanocomposite (CF-MF-NC) was evaluated for adsorptive sequestration of Eriochrome black T (EBT) dye coupled with the ultrasonic irradiation. CF-MF-NC exhibits saturation magnetization of 38.17 emu/g, BET surface area of 47.67m2/g, and average pore diameter of 10.17 nm, which makes it a potential magnetic nano-scale adsorbent. The CF-MF-NC has shown superior adsorptive performance (~88%) towards EBT dye as compared to pure CaFe2O4 (~64%) and MnFe2O4 (~52%) and this may be due to the higher surface reactivity, and enhanced physicochemical properties of the composite. The pseudo-second order kinetic model could explain the sono-assisted adsorption of EBT dye onto CF-MF-NC and the involvement of ultrasound enhanced the diffusion rate. Performance evaluation study reveals that sono-assisted EBT dye adsorption onto CF-MF-NC was superior (~98% of EBT dye removal) to conventional adsorption process with batch stirring (78.33%) and shaker (84.34%).

Synthesis of peroxy-functionalized magnetic mesoporous silica for epoxidation of vinyl acetate

Abstract Peroxy-functionalized magnetic mesoporous silica (MMS-PA) composites containing magnetic nanoparticles (MNPs) and peroxy acids were synthesized to be used as an easily reusable heterogeneous oxidant for the epoxidation of alkenes. The presence of peroxy acid functional groups on the composites was confirmed by Fourier transform infrared spectroscopy (FTIR). Transmission electron microscope (TEM) of the MMS-PA composites revealed the irregular structure of porous silica attached with the MNPs. The surface area of the MMS-PA was calculated to be 1089 m2 g−1, which is significantly lower than that of the starting mesoporous silica. As measured using vibrating sample magnetometer (VSM), MMS-PA exhibited saturation magnetization of 0.12 emu/g, indicating that the heterogeneous oxidant could respond to an external magnet. The oxidizing activity of the synthesized MMS-PA composites was investigated using vinyl acetate as a model substrate; the yields of the corresponding epoxide products were measured using nuclear magnetic resonance (NMR) spectroscopy. At room temperature, the freshly prepared MMS-PA gave 52% yield of the product, and the yield decreased only slightly to 47% for the recycled MMS-PA obtained by reactivating the recovered MMS-PA with concentrated H2O2 in acidic medium.

Influence of order-disorder effects on the magnetic and optical properties of NiFe2O4 nanoparticles

In this study, we focused on the influence of structural order-disorder effects on the magnetic and optical properties of single-phase nickel ferrite (NiFe2O4) nanoparticles that, were synthesized by the co-precipitation method and subsequently calcined at 700, 800, 900 and 1000 °C for 120 min in ambient atmosphere. These results from X-ray diffraction and transmission electron microscopy confirm that the NiFe2O4 nanoparticles have an inverse spinel structure with high purity and crystallinity. The average particle size range between 12 nm and 42 nm depending on the calcination temperature. An analysis of the hysteresis loops revealed a ferromagnetic behavior with an increase in saturation magnetization to 13.2 emu/g from 8.2 emu/g at room temperature. At 7 K, the nanoparticles exhibited saturation magnetization of about 18.1–19.8 emu/g and change in crystallite size, as the calcination temperature increased. UV–vis diffuse spectra results showed an increase in the direct band gap in the range 1.35–1.43 eV, likely due to the increased crystallinity of the NiFe2O4 nanoparticles. Photoluminescence spectroscopy revealed a strong emission in the visible region, which can easily be attributed to the presence of structural disorders in the [FeO6], [FeO4], and [NiO6] clusters of the NiFe2O4 powders. Finally, it was found that these NiFe2O4 powders as-prepared have oxygen atoms that occupy different positions and are highly disturbed in the NiFe2O4 lattice. These findings provide insights into the magnetic and optical behavior of NiFe2O4 spinel nanocrystals, with a significant emphasis on structural order-disorder effects, and help reveal the relationship between structure and properties at the atomic level.

Valorization of Poly (ethylene) terephthalate (PET) wastes into magnetic carbon for adsorption of antibiotic from water: Characterization and application

Waste Polyethylene terephthalate (PET) bottles were pyrolyzed in the presence of nitrogen and converted into activated carbon (PETAC) by physical activation in carbon dioxide flow. An ex-situ precipitation and external reduction method were applied for the intercalation of ferromagnetic iron oxides onto the PETAC matrix. The characteristic structural and chemical properties of PETAC and magnetic PETAC (M-PETAC) were studied by Brunauer Emmett Teller (BET) surface area analysis, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) analysis, Raman spectroscopy, X-Ray Diffraction (XRD) analysis, Energy Dispersive analysis of X-rays (EDAX), Vibrating Sample Magnetometer (VSM), Thermal gravimetric analysis (TGA) and elemental analysis. Characterization results indicated that PETAC exhibited a relatively smooth and microporous texture with a surface area of 659.6 m2g-1 while M-PETAC displayed a rugged morphology with a diminished surface area of 288.8 m2g-1. XRD measurements confirmed the formation of iron oxide nanocrystallites with an average Scherrer crystallite size of 19.2 nm. M-PETAC delivered a quick response to an external magnet and exhibited saturation magnetization value of 35.4 emu g−1. PETAC and M-PETAC were explored as potential adsorbents for the adsorption of a pharmaceutical (cephalexin) from water. Isotherm analysis revealed that M-PETAC exhibited a superior adsorption capacity (71.42 mg g−1) compared to PETAC (21.27 mg g−1). FTIR analysis of the adsorbents after CEX adsorption revealed the role of FeO as the nucleation site for enhanced adsorption of cephalexin by M-PETAC.

A new evidence for the interaction between the two components in PANI/La composites

We found a new way to prove the interaction between the two components in polyaniline (PANI-DTA)/La composites by studying the specific heat. It is firstly found that PANI-DTA has a phase transition peak at −50°C. The composites (PLa) have no phase transition at −50°C, so the thermal, magnetic and electrochemical properties are different from PANI-DTA. The heat capacities of the composites are higher than that of PANI-DTA and La complex. the magnetic field dependence of magnetization (M–H) curves of PANI-DTA and PLa-2 exhibit saturation magnetization and a hysteresis loop. The electrochemical performance of the composites are greatly improved compared with PANI-DTA and La complex.

Zn-doped magnetite nanoparticles: development of novel preparation method and evaluation of magnetic and electrochemical capacitance performances

In this paper, metal ion (i.e. Zn2+) doped magnetite nanoparticles (Zn-MNPs) were prepared via a one-pot simple electrochemical platform. In this procedure, Zn-MNPs were electro-synthesized in a two-electrode system from an aqueous solution of mixed Fe(NO3)3/FeCl2/ZnCl2 (0.005 M). The applied electrochemical conditions included current density of 10 mA cm−2, bath temperature of 25 °C and deposition time of 30 min. The structural and morphological characterizations through X-ray diffraction, field emission electron microscopy and energy-dispersive X-ray proved that the fabricated Zn-MNPs samples are composed of Zn2+ doped magnetite phase with particles with average size of 20 nm. Magnetic investigation by VSM revealed that the prepared Zn-MNPs have super-paramagnetic behavior, where they exhibited saturation magnetization (Ms), remanent magnetization (Mr) and coercivity values of 54.47 emu g−1, Mr = 0.41 emu g−1 and H Ci = 10.53 G, respectively. The charge storage ability of the prepared Zn2+ doped MNPs was evaluated as electrode material for supercapacitors through cyclic voltammetry (CV) and galvanostat charge–discharge (GCD) techniques. The obtained electrochemical data showed that these materials are capable to deliver specific capacitance as high as 164.3 F g−1 at current load of 1 A g−1, and 89.4% capacity retention after 1000 GCD cycling. The results proved the suitability of the electro-synthesized nanoparticles for use in supercapacitors. Based on the obtained results, our developed electro-synthesis method was propped as a facile procedure for the synthesis of high performance Zn2+ doped magnetite nanoparticles.