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In this paper, the spinel ferrite nanoparticles Co 0.5 Ni 0.25 Zn 0.25 Bi x Fe 2−x O 4 (CNZBF) were prepared by citrate-nitrate auto combustion method. Although the substitution process involves a large ion at the expense of a small one, the lattice constant didn't introduce a regular increment behavior with irregular shifts for the peak position at 34.62°, which is related to the (311) plane. Two hypotheses were introduced to justify this behavior. The crystallite size introduced a peculiar behavior in the span of 20.88–14.78 nm with increasing the Bi3+ content. Morphological study via FE-SEM manifested that the CNZBF nanoferrites have agglomerated spherical shapes. Kubelka-Munk function and Tauc's plot for direct allowed transitions were utilized to determine the band gap of all the CNZBF nanoferrites. The doping of Bi tuned the band gap (within 1.55 to 1.25 eV), boosted the light absorption, induced efficient e/h separation, and ensuing charge migration to the Co 0.5 Ni 0.25 Zn 0.25 Bi x Fe 2−x O 4 surfaces. On account of the CNZBF advantages, a superb removal efficiency (∼96.41 %) of the sample Co 0.5 Ni 0.25 Zn 0.25 Bi 0.08 Fe 1.92 O 4 via photocatalytic degradation was achieved. After five reusability cycles the nanocatalyst Co 0.5 Ni 0.25 Zn 0.25 Bi 0.08 Fe 1.92 O 4 introduced 95.08% degradation which demonstrates a trivial efficiency decline of 1.33 % in the photocatalytic activities. These outcomes of excellent photocatalytic activity with the outstanding stability candidate the novel Co 0.5 Ni 0.25 Zn 0.25 Bi 0.08 Fe 1.92 O 4 for wastewater treatment applications. [ABSTRACT FROM AUTHOR]

Cobalt zinc chromium ferrites, which have been doped with chromium Co0.4Zn0.6-xCrxFe2O4 (x = 0.05, 0.10, 0.15, 0.20) (CZC) nanoferrites, are employed by the auto-combustion route. The magnetic and dielectric characteristics of Co–Zn nanoferrites were improved by Cr3+. Analysis using XRD, FTIR, and FESEM reveals the cubic spinel phase for CZC nanoferrites. SEM reveals a lot of clustering. The ferrite samples have cluster form with a spherical shape in the range 54.64–73.38 nm, as seen by the FESEM results. TEM studies show agglomeration. The Cr3+ concentration determines the magnetic properties of specimens. Ms declines from 62.38 emu/g to 42.59 emu/g by increasing Cr3+. For all samples, a frequency-dependent evaluation of the dielectric properties, including dielectric constant, dielectric loss, and ac conductivity, is performed. On the basis of Koop's theory, the Maxwell-Wagner polarization procedure, and the movement of electrons, the fluctuation of dielectric features at frequencies between 50 Hz and 108 Hz has been mentioned. The dielectric constant and dielectric loss tangent decreased with increasing frequency. The conduction of ferrite samples is influenced by the grain boundaries. Both recording media and high-frequency devices can benefit from using these nanoferrites. [ABSTRACT FROM AUTHOR]

In this paper, a constant quantity of Co2+ ions and a series of Ce3+ ions were used to substitute Fe3+ ions to control the magnetic and electrical properties of the pristine Zn–Mn nanoferrites with the formula Co 0.5 Zn 0.25 Mn 0.25 Ce x Fe 2-x O 4 (CZMC). The addition of a suitable content of Ce3+ ions (x = 0.1) enhanced the magnetization (with an enhancing ratio of 9.43 %), initial permeability (with an enhancing ratio of 31.06 %), and coercivity (with a decreasing ratio of 12.86 %). The CZMC nanoferrites can operate from 13.5 GHz to 16.5 GHz, which can be utilized in high frequency-based technical purposes such as magnetic memories, filters, and transformer cores. The AC conductivity results of the CZMC nanoferrites are in correspondence with Jonscher's single-power law, and the conduction mechanism is established to be attributed to the overlapping large-polaron tunneling model. Nyquist plots of the samples revealed that the diameters of the semicircles decrease as the temperature increases, confirming the semiconducting behavior with one semicircle due to the electrode and grain boundary contributions to the conduction process. The high-frequency response of the CZMC nanoferrites revealed that they could operate in the frequency range of 13.5 GHz–16.5 GHz, which is suitable for electronic and microwave devices. The dielectric loss value reduces with Ce replacement (with a decreasing ratio of 66 %), suggesting it might be a candidate for planar inductor and transformer cores at high-frequency applications. Dependence of crystallite size (D nm), magnetization (M S), coercivity (H C), dielectric constant (ε′), ac conductivity (σ ac), and dielectric loss tangent (tanδ) on Ce3+ content for CZMC nanoferrites at RT and 50 Hz. [Display omitted] [ABSTRACT FROM AUTHOR]

The phase transition of austenitic stainless steel of commercial label CL20ES and zinc ferrite nanoparticles was studied in an oxidative atmosphere of dry air to develop a low-cost, effective technique for covering-layer fabrication. CL20ES powder and zinc ferrite powder were mechanically mixed. This mixture was studied in an atmosphere of dry air at different annealing temperatures from room temperature to 900 °C. The employed characterization techniques are X-ray powder diffraction, Mössbauer spectroscopy in the transmission geometry, and scanning electron microscopy with elemental mapping. The fabricated layers were also characterized by surface-specific techniques such as conversion electron Mössbauer spectroscopy and grazing incidence X-ray powder diffraction. The analyzed powder mixture shows resistance against oxidation in dry air and high temperatures. These results were employed to produce zinc ferrite covering layers on 3D-printed cylinders of CL20ES. The results show a predisposition of zinc ferrite to be recrystallized at temperatures above 350 °C without the production of corrosive substances on steel. The zinc ferrite layers were analyzed by an ultrasonic hardness tester as well, which proved the hardness enhancement. [ABSTRACT FROM AUTHOR]

Nowadays, a strong ascending interest is given to the use of nanoparticles in soils to evaluate their benefits or risks to plants and microbes. Pea (Pisum sativum L.) of the family Fabaceae is among the crops cultivated by farmers in the winter season. From here, this study was conducted to examine the impact of arbuscular mycorrhizal fungus (AMF) and zinc ferrite nanoparticles (nano-ZnFe2O4) co-application on biochemical parameters and mineral contents of pea plants, as well as the impact of nano-ZnFe2O4 application on mycorrhizal root colonization. For this purpose, nano-ZnFe2O4 with a crystallite size of 25.4 nm was used in two different concentrations (0 and 5 µM) in pots planted with pea plants and inoculated or non-inoculated with AMF. The results showed that nano-ZnFe2O4 to some extent inhibited AMF colonization of pea plant roots. Additionally, in comparison to non-AM controls, the combined use of AMF and nano-ZnFe2O4 was successful in raising the activity of helpful enzymes (acid phosphatase, alkaline phosphatase, catalase and peroxidase) as well as biochemical parameters including primary metabolites (carbohydrates, protein, and amino acids). Moreover, an improvement in mineral nutrients uptakes in pea plants such as N, P, K and Mg appeared in the combined treatment. Therefore, nano-ZnFe2O4 coupled with AMF promises potential applications in agriculture because Zn and Fe are two essential micronutrients that need to be supplied to crop plants. Nano-ZnFe2O4 and arbuscular mycorrhiza (AM) showed synergistic effect on biochemical parameters of pea plants. Nano-ZnFe2O4 slightly reduced the mycorrhizal root colonization. Stimulation of shoot height and root length of pea plants as a result of AM fungi coupled with nano-ZnFe2O4. This study highlights new trends in enhancing the accumulation of primary metabolites (proteins, carbohydrates, and amino acids) in pea plants by AM symbiosis and nano-ZnFe2O4 application. AMF combined with nano-ZnFe2O4 augments mineral nutrition in the shoots and roots of pea plants. [ABSTRACT FROM AUTHOR]

Metal ferrites like nickel ferrite, copper ferrite, zinc ferrite, cobalt ferrite, and other ferrites are highly abundant and used as catalysts in various transformations. However, CaFe2O4 is the most abundant alkali metal ferrite, which is eco-friendly and non-toxic. CaFe2O4 is a superparamagnetic material that can be easily recovered from the reaction media due to its magnetic properties. Therefore, it has been widely used in numerous applications, such as dye degradation, removal of heavy metal ions, transesterification reaction, gas sensing, photocatalytic water splitting, drug delivery, etc. In this review, (1) magnetic properties and crystal structure of spinal CaFe2O4 are discussed, (2) potential applications of CaFe2O4 are discussed, and (3) various synthesis techniques of CaFe2O4 are demonstrated. CaFe2O4 shows photocatalytic properties due to its narrow band gap (1.9 eV), abundant functional group, and high surface area. It is found that CaFe2O4 possesses a remarkable potential for energy and environmental remediation. In this review, we have added the photocatalytic mechanism of various pollutants. At last, future perspectives are given for developing novel, sustainable CaFe2O4 or CaFe2O4-based nanocomposite. [ABSTRACT FROM AUTHOR]

This document explores the impact of adding zinc to nickel ferrite thin films and its effect on their electrophysical properties. The films were created using solid-phase pyrolysis and were composed of nanocrystallites with an average size of 18-21 nm. The resistance of the films exhibited temperature dependence, particularly in films with higher zinc concentrations. The study emphasizes the significance of zinc addition in influencing the microstructure and properties of nickel ferrite thin films. [Extracted from the article]

Heterogeneous interface regulation plays an important role in tailoring the intrinsic electromagnetic (EM) properties for obtaining excellent EM wave absorption, which still faces huge challenge. In this work, bi‐metal MOFs‐derived ZnFe2O4–ZnO‐Fe@C (ZZFC) microspheres with custom‐built heterogeneous interfaces are successfully fabricated via a confined growth strategy. Bi‐metal Fe–Zn–ZIF with tailored coordination structure and chemical bonding are first selected as the precursor template. After undergoing the annealing process, the metal Fe2+ host is converted into magnetic Fe nanoparticles (NPs). The Zn2+ host is transformed into semiconductor zinc oxide (ZnO) with increasing (101) crystal‐oriented growth. At the same time, metal hosts Fe2+ and Zn2+ are further reacted to synthesize the zinc ferrite (ZnFe2O4). Formed Fe nanoparticles catalyze organic ligands to constitute graphitized carbon layers, which confine the further growth of ZnFe2O4, ZnO, and Fe NPs. Combined with the well impendence and synergy absorption mechanism (magnetic loss, interface polarization, and conduction loss), optimized magnetic–dielectric ZnFe2O4–ZnO‐Fe@C microspheres exhibit outstanding EM wave absorption with the minimum reflection loss −66.5 dB at only 2.0 mm thickness. Bi‐metal MOF‐derived magnetic–dielectric absorption materials with tailored heterogeneous interfaces provide a new sight to design an efficient EM wave absorption system. [ABSTRACT FROM AUTHOR]

This document is an introduction to the topic of innovative nanomaterial properties and applications in chemistry, physics, medicine, and the environment. It discusses the importance of controlling and designing nanomaterials with specific properties and highlights the interdisciplinary nature of nanomaterial research. The document also mentions the most explored types of nanomaterials, such as metallic-based and carbon-based nanomaterials, and their various applications in fields like biosensors, drug delivery, and water decontamination. Additionally, it provides a summary of 12 original research papers included in a special issue on nanomaterial synthesis and characterization. The document concludes by expressing gratitude to the authors and reviewers who contributed to the special issue. [Extracted from the article]

We have prepared Mg 1-x Zn x Fe 2 O 4 nanoparticles (x values varying from 0.0 to 0.8 by 0.2 increments) for use as catalysts for hydrogen production in the methanolysis of sodium borohydride (NaBH 4). The catalytic performance of the Mg 1-x Zn x Fe 2 O 4 nanoparticles with different zinc content for hydrogen production were evaluated in the methanolysis of NaBH 4 inside glass vessels. Different characterization techniques were used to analyse the prepared nanoparticles such as X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), Transmission Electron microscopy (TEM), and Scanning Transmission Electron microscopy STEM. The average size of Mg 1-x Zn x Fe 2 O 4 nanoparticles was 10 nm. The largest energy band gap value was 4.77 eV for MgFe 2 O 4 nanoparticles, while the lowest value was 2.89 eV for Mg 0.2 Zn 0.8 Fe 2 O 4 nanoparticles. Mg 0.8 Zn 0.2 Fe 2 O 4 nanoparticles were proven as the catalysts with the highest hydrogeneration rate with a value of 15,957 mL min−1 g−1. [Display omitted] [ABSTRACT FROM AUTHOR]

This article introduces a ternary nanocomposite‐based flexible thin film ammonia sensor developed on transparent polyethylene terephthalate (PET) substrate in the well‐known in situ chemical oxidative polymerization technique. The nanocomposite consists of three different materials: polyaniline (PANI), reduced graphene oxide (rGO), and zinc ferrite (ZF). Keeping the PANI amount constant, seven PANI/rGO/ZF (PRZ) samples are produced by performing stoichiometric variation between rGO and ZF. Later on, various structural, morphological, and spectroscopic analysis of all the composite materials is accomplished with field emission scanning electron microscopy (FESEM), high‐resolution transmission electron microscopy (HRTEM), X‐ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible spectroscopy (UV–Vis). The sensing performance of the as‐produced sensors toward ammonia (NH3) is examined in the concentration range from 250 ppb to 100 ppm. The study reveals the excellent sensing ability of the PRZ3 sensor (rGO = 30%, ZF = 20%) achieving minimum and maximum responsivity values of ~51% and ~1052%, respectively, at the lowest (250 ppb) and highest (100 ppm) concentration of ammonia. The sensor also exhibits admirable repeatability, good dynamic responsivity, rapid response (tres ~2.9–5 s), moderately faster recovery (trec ~37.9–69.7 s), superb linearity against ppm variation (R2 ~ 0.989), low detection limit (~123 ppb), and exceptional selectivity toward ammonia. The substrate temperature variation divulges that room temperature (30°C) is the ideal temperature for getting outstanding responsivity of the sensor. The study is further accompanied by humidity variation in the incoming air and bending flexibility test of the substrate. A compulsory and legitimate model regarding the sensing mechanism is presented at the end. [ABSTRACT FROM AUTHOR]

A bio approach (mediated by Agaricus bisporus) was attempted in the present study to synthesize ferrite nanoparticles MFe2O4 (M = Zn, Cu and Co]. The synthesized ferrites nanoparticles were characterized in terms of variations in the crystallinity, dimension and sizes using standard techniques (XRD, FTIR, SEM-EDAX, Zeta potential and DLS). VSM analysis showed noticeable differences in the magnetic saturation values: zinc ferrite (12.5 emu/g); cobalt ferrite (27.5 emu/g) and copper ferrite (21.5 emu/g). In- vitro cytotoxic effect of the synthesised ferrite nanoparticles resulted in effective inhibition of colon cell line growth (SW620). The ferrite nanoparticles were also evaluated for their drug-release behaviour using doxorubicin (DOX). The results indicated that the maximum DOX delivery was 98.74% using zinc ferrite, 97.34% using cobalt ferrite and 99.52% using copper ferrite within 6 h using 10 mg of nanoparticles. From the hyperthermia results, a SAR of 337 W/g was noted using 10 mg of copper ferrite nanoparticles at an applied frequency of 335 kHz and magnetic field strength of 235 A/m. [ABSTRACT FROM AUTHOR]

Using the free (pressureless) sintering method, multiferroic ceramic composites based on two ferroelectric materials, i.e., BaTiO3 (B) and Pb0.94Sr0.06 (Zr0.46Ti0.54)0.99Cr0.01O3 (P), and magnetic material, i.e., zinc–nickel ferrite (F) were obtained. Three composite compositions (BP-F) were obtained with a constant 90/10 content (ferroelectric/magnetic) and a variable content of the ferroelectric component (B/P), i.e., 70/30, 50/50, and 30/70. Crystalline structure, microstructural, DC electrical conductivity, dielectric, and ferroelectric properties of multiferroic composites were investigated. The concept of a composite consisting of two ferroelectric components ensures the preservation of sufficiently high ferroelectric properties of multiferroic composites sintered by the free sintering method. Research has shown that the percentage of individual ferroelectric components in the composite significantly affects the functional properties and the entire set of physical parameters of the multiferroic BP-F composite. In the case of the dielectric parameters, the best results were obtained for the composition with a more significant amount of BaTiO3; i.e., permittivity is 1265, spontaneous polarization is 7.90 µC/cm2, and remnant polarization is 5.40 µC/cm2. However, the most advantageous set of performance parameters shows the composite composition of 50BP-F. [ABSTRACT FROM AUTHOR]

Geopolymers are a type of inorganic polymer that typically have a monochromatic appearance. This study investigates the formation of artificial chrysocolla by immersing these materials in Cu(II) ion solutions. The resulting synthetic chrysocolla possesses magnetic properties and characteristic silicate bands in its structure, indicating geopolymerization and a similarity to natural chrysocolla. Furthermore, the inclusion of copper and zinc ferrites in the nano-modified geopolymer matrix enhances its properties and potential antiviral properties. The antiviral test results show that synthetic chrysocolla based on nano-modified geopolymers has a mild antimicrobial effect. However, more testing is needed to determine its effectiveness against bacteriophage, as bacterial growth was observed in the area where the nano-modified geopolymer bacteriophage blend was applied. In addition to its potential antiviral properties, synthetic chrysocolla's porous structure allows it to act as an adsorbent, making it useful in the development of antiviral filters. Artificial chrysocolla can be obtained through a geopolymeric matrix by immersing it in a solution of Cu(II) ions, which can occur by ion exchange of the ions present in the aluminosilicate structure with Cu(II). Neutralization of the geopolymer matrix by washing with distilled water is required prior to immersion to ensure proper formation of chrysocolla and not copper(II) hydroxide on the geopolymer surface. Overall, this study provides evidence for the successful preparation of nano-modified synthetic chrysocolla from geopolymers and ferrites, with properties and chemical composition similar to those of natural chrysocolla. The presence of copper ions in its composition and the incorporation of copper and zinc ferrites can contribute to its use as a resource to combat viral pathogens. [ABSTRACT FROM AUTHOR]

In a wide range of applications, from consumer electronics to cutting‐edge industrial and scientific equipment, high dielectric permittivity (ε′) polymers are crucial for maximizing the performance and efficiency of electrical and electronic systems. Researchers strive to create and perfect these materials to meet the changing demands of modern technology. It is generally known that freestanding bare polymers cannot achieve high dielectric values; however, the mixing of multiple materials that are distinct is an effective technique for developing high dielectric hybrids. Polymer‐based nanoarchitectures are particularly beneficial for use in the storage of energy due to characteristics such as excellent mechanical strength, noncorrosive nature, lightweight, affordability, versatility, thermal and electrical shielding. The primary aim of this investigation is to prepare copper ferrite, zinc ferrite, and copper0.5 zinc0.5 ferrite (CuFe2O4, ZnFe2O4, and Cu0.5Zn0.5Fe2O4) nanoparticle (NP) via combustion technique using egg albumen as a fuel and these NPs were separately dispersed in polyaniline (PANI) matrix by the method of ex situ polymerization of aniline with an objective to enhance the electrical properties for energy storage and electromagnetic wave applications. Flexible freestanding films were casted via solution casting technique. X‐ray diffractogram of 5 wt.% NP dispersed PANI films confirmed the presence of NPs in the PANI matrix. Scanning electron micrograph images show the homogeneous dispersion of NPs into PANI matrix. Rather than the pure ferrite NPs, mixed ferrite highly enhance the permittivity of PANI films without much increasing its loss factor, the obtained values of ε′ of all the three ferrite added films are higher than polyvinylidene fluoride (PVDF)/(Mn0.2Zr0.2Cu0.2Ca0.2Ni0.2)Fe2O4 nanofiller. In this work notably for 5 wt.% Cu0.5Zn0.5Fe2O4 dispersed film shows the highest value of ε′ (7291) for 100 Hz at 150°C with ultralow loss factor (0.08) which is the key characteristic of an energy storage material. Thus, this present study leads the formation of a cost effective, flexible, high dielectric material, which can be a potential alternate to replace PVDF/(Mn0.2Zr0.2Cu0.2Ca0.2Ni0.2)Fe2O4 and polyvinyl alcohol/Ni0.65Cu0.35Fe2O4 polymer blends for energy storage applications. [ABSTRACT FROM AUTHOR]

Manganese‐zinc ferrite, nickel‐zinc ferrite, and the combinations of both ferrites in constant level 200 phr were incorporated into acrylonitrile‐butadiene rubber. The amount of carbon black was constant in each composite −25 phr. The second series of composites was fabricated with similar composition, but the total content of ferrites or ferrites combinations was 300 phr, while the content of carbon black was 25 phr. The work was focused on investigation of electromagnetic absorption shielding effectiveness of composites and their physical‐mechanical properties. During the study, good correlation between conductivity, permittivity, and electromagnetic absorption parameters was established. Higher conductivity was reflected in higher permittivity of composites, which subsequently resulted in their lower absorption shielding performance. The experimental outputs revealed that absorption shielding effectiveness was enhanced with increasing with proportion of nickel‐zinc ferrite, which pointed out to higher absorption shielding potential of nickel‐zinc ferrite. The physical‐mechanical properties were found not to be influenced by the type of ferrite or ferrites combinations. The higher overall content of ferrites in rubber matrix caused the decrease in tensile characteristics of composites, suggesting that ferrites are inactive fillers considering the physical‐mechanical properties. [ABSTRACT FROM AUTHOR]

Tetravalent titanium substituted lithium zinc manganese ferrite having chemical formula Li0.35+x/2Zn0.1Mn0.1TixFe2.35 − 3x/2O4 where x = 0.00, 0.15, 0.30, 0.45, 0.60, 0.75 were prepared by using the solid-state ceramic technique. Using additives V2O5 and Na2SiO3 as sintering aids, the samples were calcined and sintered at 900 °C and 950 °C, respectively for 1 h each, at a regulated heating rate of 10 °C/min. The X-ray diffraction (XRD) studies showed a single-phase spinel structure. XRD data were used to assess the structural information including density, lattice constant, and crystallite size. The additives reduced the sintering temperature and time and an increase in porosity has been observed with the increase of Ti4+ substitution. Scanning electron microscopy (SEM) was used to analyze the samples' microstructure, while Energy-dispersive X-ray (EDAX) analysis was used to identify the different elemental makeup. The fluctuation of the initial permeability and permeability loss at room temperature with a change in frequency was investigated using an impedance analyzer and found that higher substitution reduced the resonance frequency. The magnetic hysteresis studies showed that saturation magnetization reduced with an increase of Ti4+ substitution. The results obtained were analyzed and discussed systematically in the paper. [ABSTRACT FROM AUTHOR]

While the Cu substitution in NiCuZn ferrites is known to enhance densification and increase the initial permeability (μ i), little is known about its effects in the MnZn based ferrites, which naturally possess a higher saturation magnetization (M s) and μ i. In this study, the effects of Cu substitution for Mn on the power MnZn ferrites (Mn 0.71-x Cu x Zn 0.22 Fe 2.07 O 4 , x = 0.00–0.35) are investigated. With increasing Cu content, enhanced density, reduced porosity, and significant grain growth are observed. The cation distribution was determined using the Rietveld refinement, showing the strong tendency of Cu2+ ions to occupy the octahedral sites of the spinel lattice. The magnetization curves show reduced M s with increasing Cu content. The magnetic anisotropy (| K |) was also determined from the magnetization curves using the law of approach to saturation and is seen to be increased by the increasing Cu content. The reduced M s and increased | K | lead to the dramatic reduction of μ i from 2503 (x = 0.00) to 151 (x = 0.35) at room temperature. Despite the reduced M s at room temperature, the Curie temperature (T C) is seen to increase with increasing Cu content from x = 0.05 to x = 0.35, indicating the relocation of cations at an elevated temperature. The cut-off frequency (f r) is increased with increasing Cu content, which corresponds to the reduced μ i. Moreover, the core loss (P cv) of the MnCuZn ferrites was tested at 100kHz/200 mT, 200kHz/125 mT, and 300kHz/100 mT at room temperature, and is found to deteriorate with the increasing Cu content. [ABSTRACT FROM AUTHOR]

In this study, Li 0.42 Zn 0.27 Ti 0.11 Mn 0.1 Fe 2.1 O 4 ferrites were co-fired with Bi 2 O 3 –B 2 O 3 (BB) additive at low sintering temperatures (∼920 °C), and the effects of BB additive on various properties of Li–Zn ferrites were systematically investigated. First of all, the existence of BB additive would not pollute the spinel phases of Li–Zn ferrites, in contrast, it could make the ferrites well-ripened at low temperatures. The micro-morphology results revealed that the introduction of BB additive could significantly promote the grain growth, where the average diameter of grain size increased from 0.81 μm (0.0 wt % BB) to 8.12 μm (0.5 wt % BB), leading to a higher densification degree and density. Owing to the liquid phase formed in the sintering process, magnetic properties of the Li–Zn ferrites were improved with the assistance of BB additive. The saturation flux density (B s) and saturation magnetization could reach a maximum value of 319.3 mT and 74.2 emu/g, respectively. The coercivity (H c) and ferromagnetic resonance (FMR) linewidths (ΔH) could reach a minimum value of 176.3 A/m and 243.2 Oe, respectively. Finally, it is noted that the optimal values of these parameters are obtained under the condition of 0.5 wt % BB additive doped, and most magnetic properties would be deteriorated when exceeding the above content. Thus, BB additive is considered as a promising sintering aid for synthesizing Li–Zn ferrites at low temperatures, which will play a vital role in the development of low-temperature co-fired ceramics (LTCC) technology. [ABSTRACT FROM AUTHOR]

Manganese–zinc ferrite, nickel-zinc ferrite and the combination of both fillers were used for fabrication of composites. Then, carbon black was applied in combination with ferrites in the second type of composites. The main goal was to investigate the influence of fillers on absorption shielding efficiency and physical–mechanical properties of composites. It was revealed that incorporation of ferrites into rubber matrix leads to fabrication of composites that are able to absorb electromagnetic radiation. The higher was the amount of nickel-zinc ferrite in fillers combinations, the higher was the absorption shielding performance of composites. The results showed that nickel-zinc ferrite demonstrated better absorption shielding potential. The absorption shielding efficiency of composites filled with carbon black and ferrites was lower when compared to equivalent composites filled only with ferrites, which can be attributed to higher electrical conductivity of composites due to the presence of carbon black. On the other side, the incorporation of carbon black caused the improvement in physical–mechanical properties of composites, mainly the enhancement of the tensile strength, modulus and hardness. [ABSTRACT FROM AUTHOR]

In this study, the removal of methyl violet 2B (MV-2B) using conventional and sono-assisted adsorption was investigated. A magnetic adsorbent (KCZF) supported zinc ferrite and copper ferrite was prepared using kaolin. Various analyses, such as BET, SEM, EDS, FTIR, XRD, zeta potential and VSM, were performed to determine the structure of KCZF. The BET analyses indicated that specific surface area was 86.56 m2/g. The magnetization saturation value for KCZF was determined as 4.85 emu/g. The removal of MV-2B for conventional adsorption was found to be 79.7% at original pH, in a KCZF amount of 0.8 g/100 mL, an initial MV-2B concentration of 20 mg/L, a contact time of 120 min and at a temperature of 20 °C. On the other hand, sono-assisted adsorption of MV-2B was found to be 88.8% at a KCZF amount of 0.6 g/100 mL, an initial MV-2B concentration of 20 mg/L, a contact time of 30 min, original pH and at a temperature of 20 °C. The results revealed that sono-assisted adsorption exhibited higher efficiency compared to conventional adsorption, with a shorter contact time to reach equilibrium. Based on the results, it was determined that the Langmuir isotherm model was suitable for describing the conventional adsorption of MV-2B, while the Freundlich isotherm model was found to be more appropriate for the sono-assisted adsorption of MV-2B onto KCZF. Furthermore, the pseudo-second-order kinetic model provided the best description for both conventional and sono-assisted adsorption of MV-2B onto KCZF. [ABSTRACT FROM AUTHOR]

The known studies of heat treatment of copper slag are mainly directed to the recovery of metals from copper slag at the melting temperature. The conditions of increasing the strength of copper slag grains as a result of transition from amorphous to crystalline state during heating have not been studied. That is why the paper presents studies of microhardness and cutting properties of copper slag particles after heat treatment. Treatment regimens were assigned after calorimetric measurements of phase transition from amorphous to crystalline state of copper slag grains under isothermal conditions. It was found that for copper slag grains, crystallization proceeds in two stages. The first crystallization stage started at 762.6 °C (1035.75 K) and the second one at 795.1 °C (1068.25 K). Metallographic examination of microslides of copper slag grains after heat treatment at 800 °C showed that the HV microhardness value increased 1.5 times. It was found that the use of heat-treated copper slag grains for water jet cutting resulted in an accurate cut and smooth surface compared to the original abrasive. It has been revealed that heat treatment of amorphous copper slag contributed to the appearance of crystallites of sillimanite, pyrope, hematite, and zinc ferrite. [ABSTRACT FROM AUTHOR]

It is known that inflammation after surgical operations is a big problem for many people. The person is often exposed to a bacterial infection during the operation and during his visit to the hospital to change the surgical dressing or during the need to stay in the hospital to perform a surgery as an infection inside the hospital. This study included the collection of 200 samples from the site of inflammation using a cotton swab for both sexes and different ages. The isolates were diagnosed based on the phenotypic characteristics of K. Pneumoniae bacteria, conducting biochemical tests for the isolates, and comparing the results with approved references to know the genus and type of bacteria. The diagnosis was confirmed by using the API-20 system. The results showed that 50 isolates belonging to the genus K. Pneumoniae bacteria, with a rate of 25% of the total samples. Examinations of the anti-inhibitory activity of zinc ferrite nanoparticles ZnFe2O4-NPs were carried out on K. pneumoniae bacteria by double dilutions (tubes) with six double concentrations (2,4,8,16,32,64) μ g / ml. The highest inhibition percentage was at a concentration of 64 μ g / ml, with an inhibition rate of 96.5%, and the lowest inhibitory concentration of MIC bacteria was at a concentration of 2 μg / ml. [ABSTRACT FROM AUTHOR]

The ability of K.Pneumonia isolates to form biofilm was tested using the calibration plate method. The results showed that all isolates of which 50 (100%) have the ability to form biofilm, as 40 isolates (80%) were strong for biofilm formation, while 8 isolates (16%) were medium and 2 (4%) were weak for biofilm formation. The antibiotic effect of zinc nanoparticles on biofilm formation showed that out of 50 K. Pneumoniae isolates, the biofilm of 14 isolates was inhibited by (28%), and the highest inhibition rate of biofilm was at a concentration of 64 μg /ml. The antibiotic showed that the effect of zinc nanoparticles, ZnFe2O4 on the production of urease enzyme for 50 isolates of K. Pneumoniae (10 isolates) was inhibited by 20% on the production of urease enzyme, and 40 isolates by 80% were urease-producing. [ABSTRACT FROM AUTHOR]

Silver-substituted cobalt zinc ferrite series, Co x Ag 0.5-x Zn 0.5 Fe 2 O 4 (x = 0.4, 0.3, 0.2, 0.1), is synthesized using the citrate gel method, wherein ferrite formation is achieved at 600 °C. The low-temperature crystallization results in agglomerated and porous ferrites. In this sample preparation methodology, as the silver content in the series increases, metallic silver deposits at the grain boundaries, and vacancies are created at the octahedral sites. With a further increase in silver content, the magnitude of magnetic properties decreases. Antimicrobial activity increases and further decreases with an increase in silver content. The composition Co 0.4 Ag 0.1 Zn 0.5 Fe 2 O 4 exhibits both magnetic and antimicrobial behaviour. These materials can potentially be beneficial in the manufacture of removable antimicrobial agents for water purification and drug delivery systems. [ABSTRACT FROM AUTHOR]

Co1–xZnxFe2O4 (x = 0.0, 0.2, 0.4, 0.6, 0.8) cobalt zinc nanoferrites (CZF) nanoparticles were created in this study utilizing the auto-ignition procedure with citric acid as an oxidizing agent. Following thermogravimetric–differential thermal analysis, the prepared Co1–xZnxFe2O4 powder was sintered at 1000°C for 4 h. The single-phase cubic structure of Co-Zn ferrite nanoparticles was described by X-ray diffraction studies, and its outcomes show particle size fluctuation. Fourier transform infrared spectra show that phase formation occurred. Due to the ferrite samples, scanning electron microscope images demonstrate the aggregation of spherical grains. Peaks of the corresponding components Co, Zn, Fe and O were seen in the energy dispersive X-ray spectra, indicating the production of cobalt zinc ferrite. By employing a vibrating sample magnetometer to evaluate the magnetic characteristics of the ferrite output, soft ferrite material was found to be present. The range 58.55–74.46 nm is discovered to be the average crystallite size of the ferrite nanoparticles produced by field emission-scanning electron microscope. Transmission electron microscopy elaborates clustering of grains. With increase in Zn content in cobalt zinc ferrite nanoparticles, hysteresis loops were shown to be modified for magnetic characteristics, which include Ms, Mr, Hc and Mr/Ms. CZF nanoferrites can be employed in microwave devices because of their dielectric properties, i.e., the tangent loss is lower at high frequencies. Co0.2Zn0.8Fe2O4 exhibits surprisingly high dielectric permittivity with small dielectric loss and can be exploited for power storage at high frequencies. These results indicate CZF as a promising nanomaterial with unique technological applications. [ABSTRACT FROM AUTHOR]

Metal doped ferrites have wide applications in various areas such as environment, medical, agriculture, electronics, industry and so on. In this study, magnesium doped zinc ferrites (MgxZn1-xFe2O4) were prepared by sol-gel auto-combustion method. They were characterized by X-ray Diffraction (XRD) and Fourier-Transform Infra-red Spectroscopy (FTIR) techniques respectively. The doped ferrite was synthesized in two different reaction media viz, double distilled water and aloevera gel. Mg0.5Zn0.5Fe2O4 was prepared using standard methods of synthesis. Both the synthesized doped ferrites were gamma irradiated to 50 kGy and 300 kGy doses and were again characterized using XRD and FTIR techniques to study the changes in structural properties of the ferrites. The effect of two different doses of gamma radiation on ferrites is compared using XRD and IR spectra. The post irradiation structural changes were investigated in the doped ferrites. [ABSTRACT FROM AUTHOR]

In order to enhance the efficiency of heavy metal ion extraction from aqueous medium, new nanocomposite magnetic sorbents were synthesized on the base of natural zeolite (Zt) and nanoparticles of ZnFe2O4 (F). The composition, structure and physical–chemical properties of new composites with 2% (Zt-2F), 8% (Zt-8F) and 16% (Zt-16F) of zinc ferrite were characterized by XRD, BET adsorption–desorption of nitrogen, SEM with elemental mapping, TEM and magnetometry. The sorption capacity of materials was assessed towards Cu2+ ions in aqueous solutions, for which kinetic and equilibrium features of sorption were established. The maximal sorption capacity (amax, mg/g) of the studied materials increased in the order: Zt (19.4) < Zt-2F (27.3) < Zt-8F (30.2) < Zt-16F (32.8) < ZnFe2O4 (161.3). The kinetics of the sorption process followed a pseudo-second order kinetic model. The sorption equilibrium at zinc ferrite was successfully described by the Langmuir model, while the Freundlich model better fitted the sorption equilibrium on zeolite and composites. The efficiency of Cu2+ ion extraction from 320 mg/dm3 aqueous solution was 63% for composite Zt-16F and 100% for a sample of ZnFe2O4. It was established that the proposed composite sorbents provide the operation of several cycles without regeneration, they can be easily recycled with 0.1 N HCl solution and are capable of magnetic separation. The advantages of new composites and the proposed method of synthesis allow recommending these materials as effective sorbents of heavy metals from wastewater. [ABSTRACT FROM AUTHOR]

Zinc ferrite (ZnFe2O4) nanoparticles were synthesised via solution combustion method using urea as a fuel. The synthesised samples were characterised with various techniques. The cubic structure with Fd-3 m space group is confirmed by Powder X-ray Diffraction and Bragg's reflection. The crystallite size estimated from Scherrer's method was found to be 40 nm. The agglomerated irregular shape and sized surface morphology was confirmed by Scanning Electron Microscopy image. The direct energy band gap determined from Wood and Tauc's relation was found to be 5.25 eV. Using a NaI (Tl) detector and multi-channel analyser, the described sample was examined for X-ray and gamma ray shielding characteristics in the energy range of 0.081–1.332 MeV. The measured shielding values are in good agreement with the theory, however below 356 keV, there is a little variation of up to 10%. The current work offers up new possibilities for using this simple, affordable, effective and low temperature approach to create nanomaterials for X-ray and gamma ray shielding. [ABSTRACT FROM AUTHOR]

Mixed manganese–zinc ferrite nanoparticles coated with PEG were studied for their potential usefulness in MRI thermometry as temperature-sensitive contrast agents. Particles in the form of an 8.5 nm core coated with a 3.5 nm layer of PEG were fabricated using a newly developed, one-step method. The composition of Mn0.48Zn0.46Fe2.06O4 was found to have a strong thermal dependence of magnetization in the temperature range between 5 and 50 °C. Nanoparticles suspended in an agar gel mimicking animal tissue and showing non-significant impact on cell viability in the biological test were studied with NMR and MRI over the same temperature range. For the concentration of 0.017 mg/mL of Fe, the spin–spin relaxation time T2 increased from 3.1 to 8.3 ms, while longitudinal relaxation time T1 shows a moderate decrease from 149.0 to 125.1 ms. A temperature map of the phantom exposed to the radial temperature gradient obtained by heating it with an 808 nm laser was calculated from T2 weighted spin-echo differential MR images. Analysis of temperature maps yields thermal/spatial resolution of 3.2 °C at the distance of 2.9 mm. The experimental relaxation rate R2 data of water protons were compared with those obtained from calculations using a theoretical model incorporating the motion averaging regime. [ABSTRACT FROM AUTHOR]

The need for stable and well-defined magnetic nanoparticles is constantly increasing in biomedical applications; however, their preparation remains challenging. We used two different solvothermal methods (12 h reflux and a 4 min microwave, MW) to synthesize amine-functionalized zinc ferrite (ZnFe2O4-NH2) superparamagnetic nanoparticles. The morphological features of the two ferrite samples were the same, but the average particle size was slightly larger in the case of MW activation: 47 ± 14 nm (Refl.) vs. 63 ± 20 nm (MW). Phase identification measurements confirmed the exclusive presence of zinc ferrite with virtually the same magnetic properties. The Refl. samples had a zeta potential of −23.8 ± 4.4 mV, in contrast to the +7.6 ± 6.8 mV measured for the MW sample. To overcome stability problems in the colloidal phase, the ferrite nanoparticles were embedded in polyvinylpyrrolidone and could be easily redispersed in water. Two PVP-coated zinc ferrite samples were administered (1 mg/mL ZnFe2O4) in X BalbC mice and were compared as contrast agents in magnetic resonance imaging (MRI). After determining the r1/r2 ratio, the samples were compared to other commercially available contrast agents. Consistent with other SPION nanoparticles, our sample exhibits a concentrated presence in the hepatic region of the animals, with comparable biodistribution and pharmacokinetics suspected. Moreover, a small dose of 1.3 mg/body weight kg was found to be sufficient for effective imaging. It should also be noted that no toxic side effects were observed, making ZnFe2O4-NH2 advantageous for pharmaceutical formulations. [ABSTRACT FROM AUTHOR]

This work is concerned with fabricating ferrite nanoparticles of nickel–zinc with the chemical formula: Ni0.55Zn0.45Fe2−xCexO4, 0 ≤ x ≤ 0.011 by co-deposition technique and modifying their electrical, microscopic, spectroscopic, optical, electrical and dielectric properties as advanced engineering materials through doping with the cerium (Ce) element. XRD patterns displayed that the samples have a monophasic Cerium–Nickel–zinc (CNZ) spinel structure without other impurities for cerium concentration (x) ≤ 0.066. Both values of crystallite size and lattice parameters decrease from 33.643 to 23.137 nm and from 8.385 to 8.353 nm, respectively, with the increasing Ce ions substitution content from 0 to 0.066. SEM images indicate that grains of the fabricated compounds are smaller, more perfect, more homogeneous, and less agglomeration than those of the un-doped Ni–Zn nano-ferrites. The maximum intensity of first-order Raman spectral peaks (Eg, F2g(2), A1g(2), and A1g(1)) of CNZ ferrite nanoparticles are observed at about (330, 475, 650, 695) cm−1, respectively, that confirms the CNZ samples have the cubic spinel structure. The direct and indirect optical energy bandgaps of CNZ samples have a wide spectrum of values from semiconductors to insulators according to cerium concentration. The results showed that the values of dielectric constant, dielectric loss factor, and Ac conductivity and the conductivity transition temperature are sensitive to cerium ions content. AC conductivity exhibited by the CNZ samples has the semiconductor materials behavior, where the AC conductivity increases due to temperature or doping concentration. The results indicate that Ni0.55Zn0.45Fe1.944Ce0.066O4 ferrite nanoparticles may be selected for optoelectronic devices, high-frequency circuits, and energy storage applications. [ABSTRACT FROM AUTHOR]

Strontium cobalt zinc bismuth ferrites with formula are provided in this study using formula Sr0.5Co0.4Zn0.4BixFe2-xO4 at different variation of x= 0.0, 0.05, 0.10, 0.15 synthesized by Micro-emulsion techniques. To check the physical characteristics of this series (Sr0.5Co0.4Zn0.4BixFe2-xO4) of nano-ferrites using FTIR (Fourier Transformation of infrared spectroscopy), UV-visible, X-ray diffraction and scanning electron microscope. SEM and XRD analysis were used to examine the structure and morphology of manufactured nano-ferrites. The spectra of XRD demonstrated the production of a single-phase cubic spinel ferrite structure in the nanometer size range with no minor phase. When extending metal-oxygen bonds at tetrahedral and octahedral sites, FTIR analysis showed two bands centered at 592 and 410 cm-1 . Using ultraviolet-DRS, we determined that band-gap range for the synthesised magnetic materials was between 2.42 and 2.32 eV. [ABSTRACT FROM AUTHOR]

A series of pyrimidine heterocyclic compounds have been synthesized through a one-pot, three-component reaction of an aryl aldehyde, ketone and urea in the presence of nano zinc ferrite catalyst under conventional heating methods. The synthesized derivatives have been characterized by using spectral techniques such as FT-IR, 1H and 13C NMR and elemental analysis. Molecular docking studies have also been carried out to identify the protein-ligand interactions and binding affinity of the newly synthesized compounds. This work has multiple advantages of providing good yields, high efficiency and retrievable catalyst. [ABSTRACT FROM AUTHOR]

Finding the interrelation among the magnetic response of the heat mediators to an alternating magnetic field (AMF) and other relevant parameters in magnetic hyperthermia therapy (MHT) can give the possibility to accurately design high-performance nanostructured magnetic nanoparticles (MNPs). In this context, the present work investigates the effect of the zinc substitution on magnetic properties and heat-generating ability of poly vinyl alcohol-coated Zn-substituted cobalt ferrite nanoparticles (PZC NPs) with different zinc contents ( Z n x C o 1 − x F e 2 O 4 ; x = 0, 0.15, 0.3, 0.4, 0.5, 0.7), synthesized using hydrothermal-assisted co-precipitation method. The obtained results showed that the PZC NPs with an average particle size ∼ 15 nm exhibit ferrimagnetic features and their coercivity (H c) values decrease as the zinc content (x) increases. Moreover, as Z n 2 + replaces C o 2 + in the structure, saturation magnetization (M s) increases up to about 52 emu/g for PZC-30 NPs (x = 0. 3) and then decreases for higher Zn contents. The hyperthermia measurements were performed at a fixed filed frequency (f = 120 k H z) and different magnetic field strengths (H a p p l = 17 , 20 , 24. 5 k A / m). The results revealed that, as x increases, specific absorption rate (SAR) at each H a p p l first shows an increasing trend and then reaching a maximum value (at x = 0. 4) follows a decreasing trend. Moreover, the highest SAR (25.25 W/g) belongs to the magnetic fluid containing PZC-40 NPs at H a p p l = 24. 5 k A / m. Furthermore, the H a p p l -dependency of the SAR values were obtained as a power law ( S A R ∼ H a p p l n) in which the exponent n rises as x decreases, suggesting that the optimal composition tends to shift to ones with the lower x at higher H a p p l . The obtained results, revealing the high impact of the interrelation between the chemical composition and the H a p p l on the MNPs heating efficiency, can shed more light on the way to design heat mediators with optimal performance through simultaneous control of the chemical composition and the H a p p l . [ABSTRACT FROM AUTHOR]

Using Rhodamine-B (Rh B) as a model organic molecule, a co-precipitation-oxidation-mediated synthesis of cobalt-substituted zinc spinel ferrites (Co x Zn 1-x Fe 2 O 4 , x = 0 to 1) is described. Multiple methods (XRD, DRS, EDX, VSM, BET, and FESEM) were used to evaluate the synthesized cobalt zinc ferrites. The material Co 0.5 Zn 0.5 Fe 2 O 4 , which had pore diameters ranging from 3 to 50 nm and a minor peak centered at about 35 nm, displayed non-uniform shapes and sizes of the porous materials made by the aggregation of ferrite nanoparticles. The S BET Brunauer-Emmett-Teller (BET) surface area values were 10.05, 13.47, and 10.9 m2/g for ferrites, zinc ferrites, and cobalt-zinc ferrites, respectively. It was found that under ideal conditions, 99% of the Rh B dye was destroyed by the Co 0.3 Zn 0.7 Fe 2 O 4 (x = 0.3) sample within 180 min of exposure to visible light. Scavenger testing and fluorescence spectroscopy confirmed that OH and holes were the principal reactive radicals involved in the degradation process. The performance of a Co 0.3 Zn 0.7 Fe 2 O 4 photocatalyst was almost unchanged after being cycled for five consecutive cycles. Therefore, it was concluded that these photocatalysts are superior options for treating Rh B-tainted wastewater under optimum conditions (pH = 2, dose catalyst = 0.1 mg/L, concentration of pollutant = 20 mg/L, with 120 mM of hydrogen peroxide). [ABSTRACT FROM AUTHOR]

BACKGROUND: Water purification of industrial effluents containing toxic organic dyes by low‐cost biomass‐based adsorbents is not only in accordance with environmental remediation policies, but also reduces total treatment costs. The conversion of Opuntia stricta Haw. biowaste, one of the most harmful invasive plants, into absorbents can lessen the ecological problems caused by this plant species as well as create more value‐added products for water decontamination. We report on the fabrication conditions of O. stricta zinc ferrite (ZnFe2O4)‐loaded activated carbon (ZnFe2O4@AC) for the elimination of two types of dyes including Rhodamine B (RhB), methyl orange (MO) and acid yellow17 (AY), with process optimization based on response surface methodology combined with Box–Behnken design. The optimized ZnFe2O4@AC was structurally characterized by scanning electron microscopy and X‐ray diffraction. RESULTS: The optimal ZnFe2O4@AC was attained at a 1.5 ZnFe2O4:OBC ratio, 5 h carbonization time and 519 °C pyrolysis temperature. In removing RhB, MO and AY by optimized ZnFe2O4@AC, remarkable adsorption capacities (53.34–82.8 mg g−1) were achieved via confirmation tests with very low errors (<2%) and high desirability (>95%). Moreover, kinetic results suggested that the Elovich model was the best description for RhB and AY dye adsorption, whereas MO adsorption by ZnFe2O4@AC followed the pseudo‐second‐order model. The maximum adsorption capacities calculated from the Langmuir equation were determined in the order: AY (82.73 mg g−1) < RhB (125.13 mg g−1) < MO (180.51 mg g−1). CONCLUSION: ZnFe2O4@AC derived from O. stricta could be recommended as a high‐efficiency bioadsorbent for the elimination of cationic, anionic and neutral dyes. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

The pursuit of low-cost manufacturing of newly effective pigments is a pressing economic need. Thus, in this work, low-cost ZnFe2O4 spinel nanoparticles (ZF-NPs) with an average diameter of 20 nm were successfully synthesized using a simple sol–gel method, which can be extended for large-scale fabrication of a reddish nano pigment. TGA/DTA, XRD, DRS, HRTEM, and SEM/EDX investigations were used to characterize the as-prepared product. The color of synthesized NPs was studied using CIE L*a*b* colorimetric method with color coordinates of L* = 41.7, a* = 72.2, and b* = 48.8. The newly developed pigment was examined to be superior to the traditional pigment (M6001/Fe2O3: L* = 30.4, a* = 42.16, and b* = 45.7). After that, the synthesized nano pigment was integrated into both ink and paint formulations as a multifunctional coating. The inclusion of synthesized nano pigment in metal coating printing ink formulation was done to produce a good alternative and cost-effective substitute for the commercially available pigment used in the inks industry. Also, the effect of the fabricated nanoparticles on corrosion resistance and thermal stability of epoxy-based paint formulations was evaluated using different standard tests. Therefore, the ZnFe2O4 pigment should be applied as a highly efficient inorganic nano pigment. [ABSTRACT FROM AUTHOR]

The nature of nonlinear magnetoelectric (NLME) effect has been investigated at room-temperature in a single-crystal Zn substituted nickel ferrite. Tuning of the frequency of magnetostatic surface wave (MSSW) modes under an applied pulsed DC electric field/current has been utilized to probe the effect. The frequencies of the modes at 8–20 GHz were found to decrease by ~ 400 MHz for an applied DC power P of ~ 100 mW and the frequency shift was the same for all of the MSSW modes and linearly proportional to P. A model is proposed for the effect and the NLME phenomenon was interpreted in terms of a reduction in the saturation magnetization due to the DC current. The decrease of magnetization with applied electric power, estimated from data on mode frequency versus P, was − 2.50 G/mW. The frequency tuning efficiency of the MSSW modes due to NLME effects in the ferrite resonator was found to be 4.1 MHz/mW which is an order of magnitude higher than the shift reported for M-type strontium and barium hexaferrite resonators investigated earlier. The spinel ferrite resonator discussed here has the potential for miniature, electric field tunable, planar microwave devices for the 8–20 GHz frequency range. [ABSTRACT FROM AUTHOR]

Spinel ferrite-based magnetic nanomaterials have been investigated for numerous biomedical applications, including targeted drug delivery, magnetic hyperthermia therapy (MHT), magnetic resonance imaging (MRI), and biosensors, among others. Recent studies have found that zinc ferrite-based nanomaterials are favorable candidates for cancer theranostics, particularly for magnetic hyperthermia applications. Zinc ferrite exhibits excellent biocompatibility, minimal toxicity, and more importantly, exciting magnetic properties. In addition, these materials demonstrate a Curie temperature much lower than other transition metal ferrites. By regulating synthesis protocols and/or introducing suitable dopants, the Curie temperature of zinc ferrite-based nanosystems can be tailored to the MHT therapeutic window, i.e., 43–46 °C, a range which is highly beneficial for clinical hyperthermia applications. Furthermore, zinc ferrite-based nanostructures have been extensively used in successful pre-clinical trials on mice models focusing on the synergistic killing of cancer cells involving magnetic hyperthermia and chemotherapy. This review provides a systematic and comprehensive understanding of the recent developments of zinc ferrite-based nanomaterials, including doped particles, shape-modified structures, and composites for magnetic hyperthermia applications. In addition, future research prospects involving pure ZnFe2O4 and its derivative nanostructures have also been proposed. [ABSTRACT FROM AUTHOR]

The aim of this work was to fabricate a new heterogeneous catalyst as zinc ferrite (ZF) supported on gamma-alumina (γ-Al2O3) for the conversion of cyclic ethers to the corresponding, more valuable lactones, using a solvent-free method and O2 as an oxidant. Hence, the ZF@γ-Al2O3 catalyst was prepared using a deposition–coprecipitation method, then characterized using TEM, SEM, EDS, TGA, FTIR, XRD, ICP, XPS, and BET surface area, and further applied for aerobic oxidation of cyclic ethers. The structural analysis indicated spherical, uniform ZF particles of 24 nm dispersed on the alumina support. Importantly, the incorporation of ZF into the support influenced its texture, i.e., the surface area and pore size were reduced while the pore diameter was increased. The product identification indicated lactone compound as the major product for saturated cyclic ether oxidation. For THF as a model reaction, it was found that the supported catalyst was 3.2 times more potent towards the oxidation of cyclic ethers than the unsupported one. Furthermore, the low reactivity of the six-membered ethers can be tackled by optimizing the oxidant pressure and the reaction time. In the case of unsaturated ethers, deep oxidation and polymerization reactions were competitive oxidations. Furthermore, it was found that the supported catalyst maintained good stability and catalytic activity, even after four cycles. [ABSTRACT FROM AUTHOR]

The vertical microchannels phenomenon is useful in the cooling process of microelectronic devices, fuel cells and MHD (magnetohydrodynamic) micro-pumps. The understanding of this phenomenon makes these flows crucial in industries and engineering products. Objective of this paper is how Dufour, Soret and chemical reaction affect the characteristics of hybrid nanofluid (engine oil + manganese zinc ferrite ( (MnZnFe 2 O 4) + nickel zinc ferrite (NiZnFe 2 O 4) )) flow in a microchannel with two vertical parallel plates. The irreversibility analysis is considered. The bvp4c solver in MATLAB is implemented to compute the transformed system derived from the equations used to describe the present problem. The heat transfer rate and other physical parameters of relevance near both plates are explained using graphs. It has been observed that as the Brinkman number and Dufour numbers increased, the entropy production rate is significantly changed. It is noticed that there is a reduction in Bejan number with the escalation in volume fraction of NiZnFe 2 O 4 ( ϕ Ni ). The skin-friction factor declined with the rate of 0.03114 at 0 ≤ Mn ≤ 3 (near left plate) and decreased in the friction factor is 2.45896 when ϕ Ni is in the range 0 ≤ ϕ Ni ≤ 0.09 (near right plate). It is detected that when Dufour number (Du ) is at 0 ≤ Du ≤ 0.6 , heat transmission rate cuts down by 0.06935 (near the left plate). Sherwood number risen by 0.043153 (near the left plate) when Soret number (Sr ) is set to 0 ≤ Sr ≤ 0.6 . [ABSTRACT FROM AUTHOR]

In this work, the synthesis of magnetic recyclable catalyst (ZnFe2O4@PDA/COF@Pd) based on palladium nanoparticles immobilized on covalent organic framework (COF) carrier and polydopamine as the linking agent for zinc ferrite (ZnFe2O4) and COF is presented. The morphology, element composition, and surface energies of the compounds were characterized. The prepared ZnFe2O4@PDA/COF@Pd exhibits excellent catalytic activity for Suzuki coupling reaction under mild conditions (TON = 4.7 × 104, TOF = 4.7 × 104 h−1). In addition, p-nitrophenol can be completely reduced within 2–9 min in the presence of NaBH4. Besides, it has remarkable promoting effect on the degradation of dyes. The above characterizations and results indicate that COF is an ideal platform for homogeneously and dispersedly immobilizing Pd NPs, which prohibit the aggregation and leaching of Pd NPs. More importantly, in the recovery of p-nitrophenol reduction reaction, the yield of p-aminophenol can still reach more than 97% after five successive cycles, demonstrating the favorable stability and durability of ZnFe2O4@PDA/COF@Pd. ZnFe2O4@PDA/COF@Pd showed high activity in dye degradation and Suzuki reactions. The Kapp value of ZnFe2O4@PDA/COF@Pd in the reduction of p-NP was 0.0276 s−1. Polydopamine as a linker between ZnFe2O4 and COF enhanced the stability of the catalyst structure, resulting in excellent recovery efficiency and recyclability. [ABSTRACT FROM AUTHOR]

Ni-Zn ferrites have important applications in the field of soft magnetic materials due to their excellent magnetic properties, but their high bulk density hinders their widespread use. CNT/nickel-zinc ferrite (CNT/Ni0.5Zn0.5Fe2O4) nanocomposites was prepared by sol-gel method, and sintered at 1000 °C to be used as an electromagnetic wave absorber. The results showed that the morphology, impedance matching, density, electrical conductivity and absorption coefficient of CNT/Ni-Zn ferrite was controlled by the additional CNT content. The NZ3 sample containing 0.06 g of CNT showed high conductivity, and high absorption coefficient. The amount of 0.06 g of CNT was a critical amount for the CNT/Ni-Zn ferrite nanocomposites. Above this value, the increasing trend toward improved nanocomposite properties due to the agglomeration of CNTs was reversed. The absorption performance of the CNT/Ni-Zn ferrite nanocomposites are attributed to the incorporation of dielectric and magnetic loss mechanisms in which the magnetic portion is comparable to the dielectric portion. Possessing excellent magnetic and absorption properties, it has the potential to be an excellent electromagnetic wave absorbing material. [ABSTRACT FROM AUTHOR]

The high zinc and iron contents of electric arc furnace (EAF) dust in the forms of zinc ferrite (ZnFe2O4) and magnetite (Fe3O4) make it a valuable secondary source of these metals. ZnFe2O4 and Fe3O4 are known to form a solid solution at all compositions, and while ZnFe2O4 is almost insoluble in aqueous solutions, Fe3O4 easily dissolves in acid. The present work investigated the enhanced leaching behavior of ZnFe2O4–Fe3O4 solid solutions by synthesizing a series of (1 − x)ZnFe2O4–xFe3O4 solid solutions, where x = mol pct Fe3O4, via solid-state reaction and leaching using HCl acid solution. Lattice parameter variation of the synthesized solid solutions indicated a positive deviation from Vegard's law with a maximum deviation at x = 20 pct Fe3O4. Leaching results showed that almost complete dissolution was achieved using x = 30 pct Fe3O4 solid solution at 85 °C for 2 hours. The enhanced dissolution behavior at this composition was attributed to the displacement of Zn2+ ions (rZn2+tetra = 0.58 Å) by the larger Fe2+ ions (rFe2+tetra = 0.615 Å) in the tetrahedral site of the crystal lattice, which created local distortions and strains rendering the structure vulnerable to acid attack. Therefore, with proper modification of EAF dust, the dissolution of zinc and iron can be significantly improved, which is critical towards sustainable resource recycling. [ABSTRACT FROM AUTHOR]

Industrialization and urbanization have now become major factors in damaging different segments of the environment. Synthesis of novel nanomaterials for the removal of dyes and free radicals from aqueous medium has become a challenge for the researchers. The present work describes formation of novel-franklinite (ZnFe2O4) nanoparticles (FNPs) which have been synthesized adopting economical route of green method using extracts of fresh and dried leaves of Coriandrum sativum. The fabricated NPs were characterized employing state of the art analytical techniques including UV-visible, FTIR, SEM and XRD. The nanocatalyst exhibited excellent catalytic properties for the degradation of eosin yellow up to 86 % in 22 min and 90 % in 16 min using zinc-ferrite NPs synthesized using dried and fresh leaves respectively. Antioxidant activity of ZnFe2O4 in terms of DPPH and ABTS free radicals scavenging was also determined. Nanoparticles synthesized using fresh leaves exhibited better antiradical potential in comparison to NPs synthesized dried leaves. Therefore, synthesis of FNPs with active features can be achieved using extract of fresh plant. Franklinite NPs can be used as promising photocatalyst for the degradation of organic pollutants and scavenging of free radicals. [ABSTRACT FROM AUTHOR]

This work exploited the simple combustion technique to prepare Ce substituted Zn–Mn ferrite nanoparticles with the formula (Zn 0.5 Mn 0.5 Ce x Fe 2-x O 4 , where x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.1). The results of XRD confirmed the nano-spinel crystallites with a size of 25–47 nm. FT-IR results exhibit the two ferrite characteristic bands, υ 1 (∼549.49–554.49 cm−1) and υ 2 (∼371.27–377.49 cm−1). All the FE-SEM micrographs demonstrated polycrystalline, brightly structured, spherical-like forms, and multigrain agglomeration particles. The nanoferrite Zn 0.5 Mn 0.5 Ce 0.08 Fe 1.92 O 4 has the lowest coercivity (38.69 Oe) with moderate magnetization (36.94 emu/g), which may be suitable for soft ferrites' applications in communication and high-frequency technology. The further doping of Ce3+ reduced the optical band gaps (from 1.84 to 1.64 eV) and improved the visible light absorption. Moreover, we assessed the photocatalytic removal of rhodamine B (RhB) by the Ce-substituted Zn–Mg soft ferrite and their magnetic characteristics. Also, the 0.08 Ce3+-doped sample photocatalyst successfully separated photogenerated carriers and had a higher RhB removal of 97.30%. For the stability test, after five cycles, the 0.08 Ce3+-doped sample photocatalyst achieved an excellent RhB removal of 96.16%, showing their remarkable stability. The facile synthesis approach, good magnetic properties, outstanding photocatalytic performance for RhB, and excellent stability suggest that Zn 0.5 Mn 0.5 Ce 0.08 Fe 1.92 O 4 photocatalyst has a high potential for high-frequency applications and large-scale pollutant treatment. [ABSTRACT FROM AUTHOR]