ZnFe2O4 Nanocomposites Research Articles

Sustainable synthesis of ZnO and FexOy nanoparticles and their nanocomposite ZnFe2O4: Comprehensive characterization and applications in antioxidant activity and antibiotics degradation efficiency

This study focuses on developing and evaluating eco-friendly nanoparticles, specifically FexOy NPs, ZnO NPs, and a ZnFe2O4 nanocomposite (NC), for potential applications in environmental remediation and biomedicine. The nanoparticles were synthesized and characterized using X-ray diffraction (XRD), which revealed their crystalline structures with sizes of 20.3 nm for FexOy NPs, 22.1 nm for ZnO NPs, and 10.9 nm for ZnFe2O4 NC. Fourier-transform infrared (FTIR) spectroscopy identified functional groups, while UV–visible spectroscopy determined band gap energies of 2.35 eV, 3.38 eV, and 2.68 eV for FexOy NPs, ZnO NPs, and ZnFe2O4 NC, respectively. Morphological analysis via scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that FexOy NPs have cubic, hexagonal, and tetragonal forms, ZnO NPs are hexagonal nanorods, and ZnFe2O4 NC has a hexagonal-faced cubic structure. Antioxidant activity, assessed through the DPPH assay, revealed that ZnFe2O4 NC had the highest potency. Additionally, under sunlight irradiation, ZnFe2O4 NC demonstrated superior degradation of the antibiotic cephalexin (96 % within 30 min) compared to FexOy NPs (58.2 %) and ZnO NPs (52 %), with respective kinetic rate constants of 0.109 min−1, 0.029 min−1, and 0.025 min−1. These results highlight the nanoparticles’ potential for environmental and biomedical applications.

Synthesis, characterization, wastewater treatment & plant growth application of ZnFe2O4/Bi2O3 nanocomposite

Vital for the prospective and sustainable environment, Bi2O3, ZnFe2O4 and ZnFe2O4/Bi2O3 (BZF) nanocomposite was synthesized in the present study by utilizing conventional combustion technique by green approach fueling with Aloe vera extract. The crystallite size calculated using Debye-Scherrer formula from X-Ray Diffraction (XRD) spectrum of BZF nanocomposite is ∼27 nm validated by XRD spectrum. Band gap of the nanocomposite is estimated using UV-Vis Diffuse Reflectance Spectra (DRS) analysis and was found to be 2.73 eV. The findings of the investigations have been validated by applications in photocatalytic degradation of acid green dye. The usage of Bi2O3, ZnFe2O4 and BZF nanocomposite as a catalyst for the degradation of acid green (AG) dye being subjected to visible light at ambient temperature results in improved photocatalytic response for Bi2O3, ZnFe2O4 and BZF nanocomposite was 88 %, 93 % and 97 % for 120 min respectively. Notably, the environmental impact of the entire technique has been examined in terms of the development of green gram plants displaying effective plant growth using the treated dye wastewater.

Electrochemical and dielectric analysis of multifunctional GQDs@PEG@Mg-ZnFe2O4 ternary nanohybrid for low-frequency electronics, water splitting, and sustainable energy storage applications

This work explores the potential of GQDs@PEG@Mg-ZnFe2O4 nanocomposite in water splitting and energy storage applications. The synthesized hybrid showed remarkable dielectric properties indicating its potential for low-frequency telecommunications and electronics applications. The impedance spectroscopy disclosed the contribution of grains and grain boundaries in the realization of colossal permittivity (104) in GQDs@PEG@Mg-ZnFe2O4. Moreover, GQDs@PEG@Mg-ZnFe2O4 showed excellent energy storage performance, indicated by its specific capacitance of 100 Fg−1 and a retention ratio of 99 % over 1000 cycles at a 1 Ag−1 current density. GQDs@PEG@Mg-ZnFe2O4 nanohybrid also showed remarkable electrocatalytic activity, both for hydrogen evolution reaction and oxygen evolution reaction. The determined Tafel slope value was found to be 90 mVdec−1 and 110 mVdec−1 at a 10 mA/cm2 current density, respectively. These results highlight the multifunctional nature of the GQDs@PEG@Mg-ZnFe2O4 nanocomposite and its potential as a versatile material to address challenges in both energy storage and conversion technologies.

Design and synthesis of vancomycin-functionalized ZnFe2 O4 nanoparticles as an effective antibacterial agent against methicillin-resistant Staphylococcus aureus.

The emergence of antibiotic-resistant bacterial infections is a principal threat to global health. Functionalization of nanomaterial with antibiotics is known as a useful method for increasing the effectiveness of existing antibiotics. In this study, vancomycin-functionalized ZnFe2 O4 nanocomposite (ZnFe2 O4 @Cell@APTES@Van) was synthesized, and its functional groups and particle size were characterized using Fourier-transform infrared spectroscopy, thermogravimetric analysis, dynamic light scattering, scanning electron microscope, and transmission electron microscopy. The antibacteria activity of the synthesized nanocomposite was evaluated using minimum inhibitory concentration and minimum bactericidal concentration against Escherichia coli, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA). Cytotoxicity assay was done by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilidemethod. Characterization analyses of synthesized nanocomposite confirmed the binding of vancomysin on the surface of ZnFe2 O4 @Cell@APTES. Nanocomposite exhibited an aggregated semi-spherical structure with hydrodynamic radii of ∼382 nm. In vitro antibacterial activity test showed that vancomycin and vancomycin functionalized ZnFe2 O4 have no antibacterial effect against E. coli. S. aureus was sensitive to vancomycin and ZnFe2 O4 @Cell@APTES@Van NPs and ZnFe2 O4 NPs did not improve vancomycin antibacterial activity against these bacteria. MRSA is resistant to vancomycin while ZnFe2 O4 @Cell@APTES@Van NPs was efficient in inhibiting MRSA growth. In summary, this study showed that attachment of vancomycin to ZnFe2 O4 NPs was increased its antibacterial activity against MRSA.

Thermal performance of novel ZnFe2O4 and TiO2-doped MWCNT nanocomposites in transformer oil

Efficient heat transfer and optimal dielectric properties are pivotal factors in ensuring the reliability and longevity of transformers, essential components in modern power systems. This study aimed to harness the potential of nanofluids to enhance both heat transfer and dielectric characteristics of transformer oil (TRO), addressing the challenges posed by increasing energy demands. A comprehensive investigation was conducted involving the synthesis of nanofluids with distinct nanoparticle compositions and concentrations. The experimental approach encompassed diverse characterization methods, namely SEM, EDX, zeta potential analysis, DLS, and FT-IR. These techniques were employed to gain insights into the prepared nanofluids’ structural, elemental, and thermal properties, facilitating a comprehensive understanding of their behavior. Notably, the incorporation of nanoparticles led to substantial enhancements in thermal conductivity and volumetric-specific heat of the nanofluids. Convective heat transfer coefficients (CHTC) and Nusselt numbers (Nu) were evaluated under forced convection conditions, revealing improvements ranging from 9% to 21%. These findings highlight the potential for nanofluids to significantly enhance heat transfer efficiency, which is crucial for efficient transformer operation. Furthermore, the breakdown voltage (BDV) investigation identified strategies to counter BDV reduction by employing nanoparticles within nanocomposites. This approach aimed to improve the dielectric performance of the nanofluids, a critical aspect of maintaining transformer insulation. These findings bridge the gap between advanced nanotechnology and practical applications in power systems, providing insights into enhancing transformer efficiency and reliability.

The synergistic triad of graphene quantum dots, polymer, and ferrites for the photodegradation of dyes in aqueous solution

This work aimed to investigate photocatalytic properties of GQDs@PEG@Mg–ZnFe2O4 nanocomposite, composed of graphene quantum dots (GQDs), polyethylene glycol (PEG), and Mg–ZnFe2O4, for the degradation of methylene blue (MB) and crystal violet (CV). This nanocomposite was synthesized using facile ultrasonics-assisted methodology. XRD analysis confirmed the formation of the spinel structure of the Mg–ZnFe2O4 in the nanocomposite, whereas the presence of GQDs and PEG was confirmed by Fourier transform infrared spectroscopy. Scanning electron microscopy (SEM) revealed a reduction in agglomeration and particle size in the ternary nanocomposite. The GQDs@PEG@Mg–ZnFe2O4 nanocomposite demonstrates a remarkable degradation efficiency of 98 % for CV and MB dyes in the presence of sunlight in 120 min, indicating its potential as an efficient photocatalyst. Vibrating sample magnetometer (VSM) analysis confirmed the superparamagnetic behavior of the GQDs@PEG@Mg–ZnFe2O4 nanocomposite which enables magnetic recovery of the photocatalyst after the degradation process. Overall, this study emphasizes the utilization of an environmentally friendly approach to effectively eliminate organic pollutants from wastewater, addressing a crucial environmental concern.

A proficient hydrothermally designed Au-TiO2/ZnFe2O4 composite for ciprofloxacin removal in wastewater under natural solar light

This study presents the development of an Au-TiO2/ZnFe2O4 nanocomposite photocatalyst through a hydrothermal method and used for the mineralization of ciprofloxacin under natural solar light exposure. The nanocomposite's crystalline structure, nanostructure, and optical characteristics were thoroughly investigated using XRD, FT-IR, XPS, SEM, EDX, ECM, HR-TEM, UV–vis DRS, and PL analysis. The XPS analysis confirmed the successful synthesis of the Au-TiO2/ZnFe2O4 composites.Notably, the Au-TiO2/ZnFe2O4 composite exhibited significantly enhanced photocatalytic efficiency compared to both TiO2/ZnFe2O4 and TiO2 alone in the degradation of ciprofloxacin. The improved performance is attributed to the introduction of Au nanoparticles, which act as electron traps, facilitating efficient charge separation and increasing light absorption in the visible region.Furthermore, the synthesized catalyst displayed remarkable stability over five cycles and could be easily recovered and reused without loss of efficacy. This work demonstrates the potential of the Au-TiO2/ZnFe2O4 nanocomposite as a promising and sustainable photocatalyst for the degradation of ciprofloxacin in water treatment applications under solar light exposure.

Synergistic role of metal oxide loading cocatalysts on photocatalytic degradation of organic pollutants and inactive bacteria over template-free ZnFe2O4 nanocubes

For wastewater treatment, a highly reliable and ecologically friendly oxidation method is always preferred. This work described the production of a new extremely effective visible light-driven Ag2Ox loaded ZnFe2O4 nanocomposties photocatalyst using a wet impregnation technique. Under visible light irradiation, the produced Ag2Ox loaded ZnFe2O4 nanocomposties were used in the photodegradation of rhodamine B (RhB) and Reactive Red 120 (RR120) dyes. Analysis using X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy revealed that Ag2Ox nanoparticles were well dispersed on the surface of ZnFe2O4 NPs and that the Ag2Ox loaded ZnFe2O4 NPs were created. When compared with bare ZnFe2O4 NPs, Ag2Ox-loaded ZnFe2O4 nanocomposites showed better photocatalytic activity for RhB and RR120 degradation under visible light (>420 nm) illumination. The reaction kinetics and degradation methodology, in addition to the photocatalytic degradation functions of Ag2Ox-loaded ZnFe2O4 nanocomposites, were thoroughly investigated. The 3 wt% Ag2Ox loaded ZnFe2O4 nanocomposites have a 99% removal efficiency for RhB and RR120, which is about 2.4 times greater than the ZnFe2O4 NPs and simple combination of 1 wt% and 2 wt% Ag2Ox loaded ZnFe2O4 nanocomposites. Furthermore, the 3 wt% Ag2Ox loaded ZnFe2O4 nanocomposites demonstrated consistent performance without decreasing activity throughout 3 consecutive cycles, indicating a potential approach for the photo-oxidative destruction of organic pollutants as well as outstanding antibacterial capabilities. According to the findings of the experiments, produced new nanoparticles are an environmentally friendly, cost-efficient option for removing dyes, and they were successful in suppressing the development of Gram-negative and Gram-positive bacteria.

A strategy to improve dielectric permittivity of Mg–Zn ferrite by using silver nanoparticles

In this work, we used silver nanoparticles (Ag NPs) to enhance the dielectric properties of magnesium-zinc ferrite (Mg–ZnFe2O4) by enhancing local electric field with the creation of nano/micro capacitors between conducting metal particles (Ag NPs) and insulating host (Mg–ZnFe2O4). Mg–ZnFe2O4 was synthesized using the sol-gel method and silver NPs were decorated on magnesium zinc ferrite (Ag@Mg–ZnFe2O4) by employing a sonication approach. The effect of Ag NPs concentration was studied on the structural, morphological, optical, dielectric, and magnetic properties of Ag@Mg–ZnFe2O4 nanocomposite. X-ray diffraction (XRD) confirmed the presence of cubic Mg–ZnFe2O4 and face-centred cubic (FCC) Ag NPs in Ag@Mg–ZnFe2O4 nanocomposite. The structural parameters such as lattice strain, crystallite size and microstrain were correlated with Ag NPs concentration. The morphological study of Ag@Mg–ZnFe2O4 showed uniform decoration of silver at low concentrations; higher concentrations of silver led to reduced covering due to the agglomeration tendency of Ag NPs. Diffused reflectance spectroscopy (DRS) was employed to estimate the effect of Ag NPs on the optical bandgap of Mg–ZnFe2O4. The bandgap narrowing was observed due to the overlapping of the Ag conduction band with the valence band of Mg–ZnFe2O4. All Ag@Mg–ZnFe2O4 samples showed superparamagnetic behaviour and the saturation magnetization was decreased with the increase in the non-magnetic Ag nanoparticles in the nanocomposite. Impedance spectroscopy (IS) was employed to comprehensively analyze the dielectric properties of Ag@Mg–ZnFe2O4. Complex impedance plane plots confirmed the involvement of relaxation phenomena related to grains and grain boundaries in the observed dielectric properties. The decoration of silver nanoparticles was associated with the realization of a high dielectric constant (∼104) in all prepared samples at low frequency. Moreover, uniform decoration of silver was found to show a more stable dielectric constant with relatively low dielectric loss.

Thermal and bisphenol-A adsorption properties of a zinc ferrite/β-cyclodextrin polymer nanocomposite.

The present study investigated the use of a nanocomposite, produced by reinforcing nanosize zinc ferrite (ZnFe2O4) in a porous β-CD based polymeric matrix (β-CD-E-T/ZnFe2O4), for the removal of Bisphenol A (BPA) from aqueous solutions via adsorption. The thermal stability of the β-CD-based polymer and β-CD-E-T/ZnFe2O4 nanocomposite were investigated using simultaneous thermal analysis at four heating rates. Non-isothermal isoconversion methods were employed to study the thermal degradation kinetics of the β-CD based polymer before and after ZnFe2O4 nano-filling. The results showed that ZnFe2O4 nano-reinforcement increased the activation energy barrier for the thermal degradation of the β-CD-based polymeric matrix. Adsorption experiments showed that the β-CD-E-T/ZnFe2O4 nanocomposite exhibited very high BPA adsorption within 5 minutes. Isotherm, kinetics, and thermodynamic investigations revealed that the adsorption of BPA was via multilayer adsorption on a heterogeneous β-CD-E-T/ZnFe2O4 surface. The thermodynamic studies indicated that BPA adsorption on β-CD-E-T/ZnFe2O4 was spontaneous and exothermic. Overall, the β-CD-E-T/ZnFe2O4 nanocomposite showed less thermal degradation and high efficiency for removing BPA from contaminated water, indicating its potential as a promising material for wastewater treatment applications.

Zinc ferrite ZnxFe3–xO4 nanocomposites as efficient photo catalysts: a study of synthesis, properties and catalytic activity

Zinc ferrite nanocomposites ZnxFe3−xO4 (x = 0, 0.5, 0.7, 0.8, 0.9, and 1) were successfully synthesized using the sol-gel co-precipitation technique. The physicochemical properties of the resulting nanocomposites were investigated using X-ray diffraction (XRD), Rietveld refinement technique (GSASII), scanning electron microscopy (SEM), Fourier transforms infrared (FTIR) spectrometry, UV/vis spectroscopy, and a vibrating sample magnetometer (VSM). The predominant phase in all of the samples was found to be ZnFe2O4 spinel, with other phases such as Fe2O3 and Fe3O4 also present. The crystallite size ranged from 6.87 to 10.88 nm, and the resulting spinel phase powder had grain sizes between 100 and 220 nm. The lattice constants and coercivity of the samples increased with increasing Zn concentration, while saturation magnetization decreased. The photocatalytic activity of the nanocomposites for the photo-degradation of methylene blue (MB) aqueous solution was investigated, and the ZnFe2O4 nanocomposites showed the highest MB degradation rate and efficiency (94%) within 60 min of UV and visible light irradiation. These results demonstrate the potential of ZnFe2O4 nanocomposites synthesized via the sol-gel co-precipitation technique for photocatalytic applications.

ZnFe2O4 spinel oxide incorporated photoanodes as light-absorbing layers for dye-sensitized solar cells

Herein, nanoparticles of zinc ferrite (ZnFe2O4) were initially synthesized by chemical co-precipitation method followed by ultrasonication. Then mixed with TiO2 (P25), and subsequently used as photoanode for dye-sensitized solar cell. ZnFe2O4 nanocomposites were found to be active in the visible region of the solar spectrum, while P25 showed absorption in the UV region, demonstrating a possibility of wider absorption band and higher photoelectric conversion efficiency. Composite photanode (with 0.1 wt% ZnFe2O4) based cell showed high power conversion efficiency (PCE) of 4.55%, whereas, the PCE of the cell with pure TiO2 as photoanode was 3.27%. Thus, there was an 39% enhancement of PCE for the composite photanode based cell..

Toward enhanced visible-light photocatalytic dye degradation and reusability of La3+ substituted ZnFe2O4 nanostructures

The present work focused on the synthesis of novel ZnLaxFe2−xO4 catalysts (x = 0, 0.01, 0.03, 0.05) and their utilization for the photocatalytic degradation of Rhodamine B dye. Structurally, the band gap energy of the catalysts tended to decrease (1.94–1.70 eV) with increasing the amount of La3+ dopant. ZnLa0.05Fe1.95O4 had an average particle size (40 nm), high surface area (41.07 m2 g−1) and large pore volume (0.186 cm3 g−1). Moreover, the effect of doping ratio, reaction time, H2O2 concentration, catalyst loading on the treatment performance of La3+ substituted ZnFe2O4 nanocomposites was investigated. ZnLa0.05Fe1.95O4/H2O2 system exhibited the highest degradation efficiency of 99.5% and nonlinear pseudo first-order kinetic reaction rate (14.8 × 10−3 min−1) in the presence of visible light irradiation. The key role of reactive oxygen species involving •O2− and •OH radicals was well explained through the scavenger study. A plausible mechanism of the degradation of Rhodamine B dye was also proposed. Due to two advantageous points including high recyclability (up to 4 cycles) and stability, La3+ substituted ZnFe2O4 nanocomposites can be an effective and competitive catalyst for the visible light-driven photodegradation of toxic dyes in the real wastewaters.

Simple synthesis of conjugated polyvinyl alcohol derivative-modified ZnFe2O4 nanoparticles with higher photocatalytic efficiency

Conjugated polyvinyl alcohol derivative (CPVA)/ZnFe2O4 nanocomposite was synthesized by a simple liquid-solid phase mixing and thermal dehydration/conjugation method. The CPVA/ZnFe2O4 nanocomposite showed not only stronger photocatalytic activity than ZnFe2O4 nanoparticles and previously reported MgFe2O4/CPVC and ZnFe2O4/CPVC photocatalysts (specifically, the photocatalytic activity of CPVA/ZnFe2O4 was 3 times that of ZnFe2O4, and 300 mg CPVA/ZnFe2O4 can achieve almost complete reduction of the Cr(VI) in 300 mL 50 mg/L K2Cr2O7 aqueous solution after 300 min visible-light irradiation), but also remarkable reuse performance in the visible-light-activated reduction of aqueous Cr(VI). Furthermore, the CPVA/ZnFe2O4 nanocomposite can be separated from the solution by magnetic attraction. The elevated photocatalytic activity of CPVA/ZnFe2O4 nanocomposite was experimentally found to be due to its more efficient transfer and separation of photo-induced charges. The proposed modification of ZnFe2O4 using CPVA is effective, economical, and environmental friendly, and the CPVA/ZnFe2O4 nanocomposite photocatalyst has potential in utilizing sunlight for treating Cr(VI)-polluted water.

RGO Sheets/ZnFe2O4 Nanocomposities as an Efficient Electro Catalyst Material for I3−/I− Reaction for High Performance DSSCs

In this paper, Reduced Graphene Oxide (rGO)/ZnFe2O4 (rZnF) nanocomposite is synthesized by a simple hydrothermal method and employed as a counter electrode (CE) material for tri-iodide redox reactions in Dye sensitized solar cells (DSSC) to replace the traditional high cost platinum (Pt) CE. X-ray diffraction analysis and High resolution Transmission electron microscopy, clearly indicated the formation of rZnF nanocomposite and also amorphous rGO sheets were smoothly distributed on the surface of ZnFe2O4 (ZnF) nanostructure. The rZnF-50 CE shows excellent electro catalytic activity toward I3− reduction, which has simultaneously been confirmed by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization measurements. A DSSC developed by rZnF-50 CE (η = 8.71%) obtained quite higher than the Pt (η = 8.53%) based CE under the same condition. The superior performances of rZnF-50 CE due to addition of graphene in to Spinel (ZnF) nanostructure results in creation of highly active electrochemical sites, fast electron transport linkage between CE and electrolyte. Thus it’s a promising low cost CE material for DSSCs.

Insights into photocatalytic mechanism for the rational design of p-n heterojunction by decorating mesoporous SnS2 over ZnFe2O4 nanocomposite for accelerated visible light photocatalysis

Binary p-n heterojunction of ZnFe2O4/SnS2 nanocomposite (NCs) was constructed by sonochemical assisted technique for enhanced visible light induced photocatalytic performance. The narrow bandgap of 2.21 eV facilitated the photocatalyst be to active under visible-light irradiation. The rate of photodegradation of methylene blue (MB) dye by optimized-NCs ratio was observed to be remarkable with multifold enhancement than pristine ZnFe2O4 and SnS2. The interfacial contact enforces an internal electric field dependent directional charge migration which hinders charge recombination that was verified by reduced photoluminescence intensity in NCs. The degradation process was found to follow pseudo-first order kinetics. The major ROS involved in the photodegradation process were found to be hydroxyl (.OH) and superoxide (.O2-) radicals which were identified through the scavengers assay. The NCs were subjected to six consecutive cycles in order to test its structural stability and reusability. This work provides guidance for rational design of heterojunction with superior activity and it reflected the potential of ZnFe2O4/SnS2 NCs as a promising photocatalyst to remove toxic pollutants from the aqueous bodies.

Polyethersulfone hybrid ultrafiltration membranes fabricated with polydopamine modified ZnFe2O4 nanocomposites: Applications in humic acid removal and oil/water emulsion separation

This study explored the impact of eco-friendly polydopamine (PDA) coated ZnFe2O4 nanocomposites (PDA@ZnFe2O4 NCs) as nanofillers to fabricate a new class of polyethersulfone (PES) hybrid ultrafiltration (UF) membranes for wastewater treatment applications. The hybrid UF membrane was prepared by incorporating PDA@ZnFe2O4 NCs into PES via the non-solvent induced phase separation (NIPS) process. The PDA@ZnFe2O4 NC was characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Additionally, the morphology and performance of the prepared hybrid membranes were characterized by SEM, contact angle, surface charge, and thermogravimetric analysis (TGA). The incorporation of PDA@ZnFe2O4 NC into the PES membrane affects the porosity, mean pore radius, hydrophilicity, and thermal stability of the developed hybrid membranes. The pure water flux of the PES hybrid membrane with 4 wt% PDA@ZnFe2O4 reached ∼687 L/m2 h, which is about 188% higher than that of the pristine PES membrane. The performance of the PES/ PDA@ZnFe2O4ultrafiltration hybrid membrane was also investigated using humic acid (HA) foulant and oil/water emulsion individually. Compared to the pristine PES and PES/ZnFe2O4 membranes, the developed hybrid membranes showed enhanced permeability and HA foulant removal. HA's removal efficiency has improved from ∼65% in the pristine PES membrane to ∼94% in the 4 wt% PDA@ZnFe2O4 hybrid membrane. The abundant functional groups on the PDA@ZnFe2O4 NC surface also enhanced the separation of the oil/water emulsion (96%). In both the HA and oil/water emulsion separation tests, the flux recovery ratio (FRR) and reversible fouling ratio (Rr) were also significantly improved, suggesting that the PES/PDA@ZnFe2O4 membrane was a very promising candidate for HA removal and treatment of oily wastewater.

Magnetic and optical properties of synthesized ZnO–ZnFe2O4 nanocomposites via calcined Zn–Fe layered double hydroxide

Abstract In this article, Zn–Fe layered double hydroxide (Zn–Fe–CO3–LDH) precursors with 1, 2, 3, and 4 values of Zn2+/Fe3+ molar ratio were prepared by coprecipitation method at pH = 8. ZnO/ZnFe2O4 nanocomposite was obtained as the calcination process of LDH precursors. Herein, we explore a prospective strategy to synthesize the zinc ferrite nanostructure by the calcination of Zn–Fe–CO3–LDH precursors. Powder X-ray diffraction (PXRD) exhibited two phases (ZnO and ZnFe2O4). Hall method has been used to calculate the grain size of ZnFe2O4 and was obtained between 19 nm and 32 nm. Magnetic measurements of the ZnFe2O4 phase after the subtraction of the paramagnetic contribution from the whole hysteresis loop of ZnO/ZnFe2O4 nanocomposite were investigated using VSM. The high coercivity values of ZnFe2O4 nanoparticles (~2600 Oe) and low values of the anisotropy constant (0.0004–0.0796) J/m3 were observed which were useful for high-density storage devices application. The values of the optical band gap of the ZnFe2O4 phase were obtained above the bulk value (2.18–2.33 eV) due to the nanosized ZnFe2O4 nature. The Urbach tail energy of ZnFe2O4 nanoparticles was found between 160.3 and 194.1 meV which indicated high localized defect levels in the forbidden band gap of prepared samples. The refractive index relation with photon energy showed normal dispersion behavior for samples at the range below 1.8 eV and anomalous dispersion behavior at the range above 1.8 eV. The values of normal dispersion parameters were calculated in this work for ZnFe2O4 nanostructure as new results which were candidate material in telecommunication applications. All these parameters, in general, increased with the increasing of the Zn2+/Fe3+ molar ratio.

Novel Ag–TiO2/ZnFe2O4 Nanocomposites for Effective Photocatalytic, Electrocatalytic and Cytotoxicity Applications

We report the preparation and characterization of a new heterostructured Ag-TiO₂/ZnFe₂O₄ (ATZ) nanocomposite. X-ray diffraction (XRD) reveals the presence of spinel type ZnFe₂O₄ and anatase TiO₂. Scanning electron microscope (SEM) images of ATZ nanocomposites show that Ag nanoparticles are successfully loaded on the composite Ag-TiO₂ and is uniformly distributed on surface of ZnFe₂O₄ forming a nanocomposite with an approximate particle size of 44.8 nm. High-resolution transmission electron microscope (HR-TEM) analysis clearly indicates the particles with spherical and hexagonal structure and sizes of most of the particles are below 50 nm. Ultra violet-visible diffuse reflectance spectra (UV-vis-DRS) show that Ag-TiO₂/ZnFe₂O₄ has increased visible absorption than TiO₂. Photoluminescence (PL) spectra shows that the intensity of ATZ is low relative to prepared TiO₂. The photocatalytic degradation of Reactive Yellow 86 (RY 86) dye was studied. Based on the band gap energies of TiO₂ and ZnFe₂O₄, a mechanism of degradation is given. Photocatalytic activity results suggest that as-prepared ATZ shows higher photodegradation efficiency than pure TiO₂. The main reactive oxidative species involved in the degradation and stability of photocatalyst were also investigated. ATZ shows higher electrocatalytic activity than TiO₂ for methanol electrooxidation. The cytotoxicity of ATZ was analysed. Multifunctionality of ATZ makes it useful for environmental and biomedical applications.

Structural, optical, and dielectric properties of Cu, Ni-doped Zn ferrites

Ferrite nanocomposites with the composition Cu0.5Zn0.5Fe2O4 and Ni0.5Zn0.5Fe2O4 were prepared by co-precipitation method. The effect of dopant to spinel ferrite ZnFe2O4 on the structural, morphological, optical, and dielectric properties of the as-prepared Cu-Zn and Ni-Zn ferrites were investigated. The structural, elemental, and optical properties conducted by using X-ray diffraction (XRD) technique with Cu/Kα radiation, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Raman spectroscopy, and UV–Vis reflectance spectroscopy. For the electrical properties of the Cu-Zn and Ni-Zn ferrites, a real part of the dielectric constant and AC conductivity have been investigated with a frequency range of 20 Hz to 10 MHz at different temperature for each sample. The substitutions of Cu and Ni into the ZnFe2O4 nanocomposites crystal size calculated 20.36 nm for Cu-Zn ferrite and 10.95 nm for Ni-Zn ferrite. Also, the energy band gap of Cu-Zn ferrite is 2.6 eV and Ni-Zn ferrite is 2.83 eV. These results show that the energy band gap is increased when the crystal size is reduced by the substitution of Ni into the Zn ferrite. The dielectric constant and AC conductivity of Cu-Zn ferrite is bigger than the Ni-Zn ferrite at low frequencies. This situation is related to the structural parameters. Also, the AC conductivity increases with an increasing frequency and temperature.