Unraveling Exchange Coupling in Ferrites Nano-Heterostructures.

The magnetic coupling of a set of SrFe12 O19 /CoFe2 O4 nanocomposites is investigated. Advanced electron microscopy evidences the structural coherence and texture at the interfaces of the nanostructures. The fraction of the lower anisotropy phase (CoFe2 O4 ) is tuned to assess the limits that define magnetically exchange-coupled interfaces by performing magnetic remanence, first-order reversal curves (FORCs), and relaxation measurements. By combining these magnetometry techniques and the structural and morphological information from X-ray diffraction, electron microscopy, and Mössbauer spectrometry, the exchange intergranular interaction is evidenced, and the critical thickness within which coupled interfaces have a uniform reversal unraveled.

Sulfurized NiFe2O4 Electrocatalyst with In Situ Formed Fe-NiOOH Nanoparticles to Realize Industrial-Level Oxygen Evolution.

Constructing composite catalysts with refined geometric control and optimal electronic structure provides a promising route to enhance electrocatalytic performance toward the oxygen evolution reaction (OER). Herein, a composite catalyst is prepared with multiple components using chemical vapour deposition method to transform crystalline NiFe2O4 into crystalline NiFe2O4@amorphous S-NiFe2O4 with core-shell structure (C-NiFe2O4@A-S-NiFe2O4), and Fe-NiOOH nanoparticles are subsequently in situ generated on its surface during the process of electrocatalytic OER. The C-NiFe2O4@A-S-NiFe2O4 catalyst exhibits a low overpotential of 275 mV while possessing an excellent stability for 500 h at 10 mA cm-2. The anion exchange membrane water electrolyzer with C-NiFe2O4@A-S-NiFe2O4 anode catalyst obtains a current density of 4270 mA cm- 2 at 2.0 V. Further, in situ Raman spectroscopy result demonstrates that in situ generated Fe-NiOOH nanoparticles are revealed to act as the catalytic active phase for catalyzing the OER. Besides, introducing A-S-NiFe2O4 in C-NiFe2O4@A-S-NiFe2O4 facilitates the formation of Fe-NiOOH nanoparticles with high-valency Ni, thus increasing the proportion of lattice oxygen-participated OER. This work not only provides an alternative strategy for the design of high-performance catalysts, but also lays a foundation for the exploration of catalytic mechanisms.

Enhancement of dielectric permittivity and Havriliak-Negami relaxation mechanism in MnFe2O4through Dy substitution.

Pristine and Dy substituted MnFe2O4, MnFe2-xDyxO4(x = 0.00, 0.02, 0.04, 0.06, 0.08 & 0.10) were successfully synthesized by sol-gel method to investigate the dielectric properties of the system. MnFe2O4exhibits a high dielectric permittivity of order 104which is further augmented by 60% through Dy substitution. This is owing to the rise in interfacial polarization resulting from localized states, dipolar polarization arising from the multiple valence states of Fe and Mn ions, atomic polarization due to structural distortion induced by strain, and electronic polarization stemming from the concentration of free charge carriers. The enhancement of induced strain, mixed valence ratio of Fe2+/Fe3+and Mn4+/Mn2+,localized states and free charge carrier concentration are confirmed from the XRD, XPS and optical studies respectively. The dielectric relaxation mechanism of MnFe2-xDyxO4follows modified Havriliak-Negami relaxation model with conductivity contribution. Complex impedance analyses further validate the contribution of grain-grain boundary mechanisms to the dielectric properties confirmed through Nyquist plots. A comprehensive analysis of conductivity reveals the significant impact of Dy substitution on the electrical conductivity of MnFe2O4. This influence is strongly related to the variations in the concentration of free charge carriers within the MnFe2-xDyxO4system. The understanding of the underlying physics governing the dielectric properties of Dy-substituted MnFe2O4not only enhances the fundamental knowledge of material behavior but also opens new avenues for the design and optimization of advanced electronic and communication devices. .

"Core/Shell" Nanocomposites as Photocatalysts for the Degradation of the Water Pollutants Malachite Green and Rhodamine B.

"Core/shell" composites are based on a ferrite core coated by two layers with different properties, one of them is an isolator, SiO2, and the other is a semiconductor, TiO2. These composites are attracting interest because of their structure, photocatalytic activity, and magnetic properties. Nanocomposites of the "core/shell" МFe2O4/SiO2/TiO2 (М = Zn(II), Co(II)) type are synthesized with a core of MFe2O4 produced by two different methods, namely the sol-gel method (SG) using propylene oxide as a gelling agent and the hydrothermal method (HT). SiO2 and TiO2 layer coating is performed by means of tetraethylorthosilicate, TEOS, Ti(IV) tetrabutoxide, and Ti(OBu)4, respectively. A combination of different experimental techniques is required to prove the structure and phase composition, such as XRD, UV-Vis, TEM with EDS, photoluminescence, and XPS. By Rietveld analysis of the XRD data unit cell parameters, the crystallite size and weight fraction of the polymorphs anatase and rutile of the shell TiO2 and of the ferrite core are determined. The magnetic properties of the samples, and their activity for the photodegradation of the synthetic industrial dyes Malachite Green and Rhodamine B are measured in model water solutions under UV light irradiation and simulated solar irradiation. The influence of the water matrix on the photocatalytic activity is determined using artificial seawater in addition to ultrapure water. The rate constants of the photocatalytic process are obtained along with the reaction mechanism, established using radical scavengers where the role of the radicals is elucidated.

High-efficiency adsorption removal of CR and MG dyes using AlOOH fibers embedded with porous CoFe2O4 nanoparticles.

Owing to the toxicity and difficulty in degradation, how to the effective separation for the residual dyes in the aqueous solution is still an issue with great challenge in the area of environmental protection. Now, to high-efficiency removal of organic dyes from the aqueous solution, we design a unique AlOOH/CoFe2O4 adsorbent with porous CoFe2O4 nanoparticles embedded on the AlOOH fibers using a simple hydrothermal technique and calcination process. The structural properties and surface characteristics of the AlOOH/CoFe2O4 composites are detailedly analyzed by XRD, FTIR, XPS, TEM and SEM. Here, the high SBET and specific porous structure are beneficial to improve the adsorption performance of AlOOH/CoFe2O4 adsorbents. Especially, when the molar ratio of AlOOH to CoFe2O4 in the AlOOH/CoFe2O4 fibers is 1:1, an optimal performance on adsorbing anionic Congo red (CR) and cationic methyl green (MG) dyes can be obtained at pH = 6.29, where the corresponding maximum adsorption capacities reach up to 565.0 and 423.7 mg g-1, respectively. Factors leading to the change in the ability of adsorbing CR and MG dyes are systematically discussed, including contact time, temperature, initial concentrations, and pH values of the solutions. Meanwhile, the uptake of CR and MG dyes can best conform to Langmuir isotherm model and pseudo-second-order adsorption kinetics. The thermodynamic analysis verifies that the dye adsorption process is spontaneous and endothermic. Moreover, from the point view of practical application, the good reusability further makes the as-synthesized magnetic AlOOH/CoFe2O4 composite be a perfect adsorbent with efficiently removing both anionic and cationic dyes from aqueous solutions.

Sustainable Cellulose Nanofibers-Mediated Synthesis of Uniform Spinel Zn-Ferrites Nanocorals for High Performances in Supercapacitors.

Spinel ferrites are versatile, low-cost, and abundant metal oxides with remarkable electronic and magnetic properties, which find several applications. Among them, they have been considered part of the next generation of electrochemical energy storage materials due to their variable oxidation states, low environmental toxicity, and possible synthesis through simple green chemical processing. However, most traditional procedures lead to the formation of poorly controlled materials (in terms of size, shape, composition, and/or crystalline structure). Thus, we report herein a cellulose nanofibers-mediated green procedure to prepare controlled highly porous nanocorals comprised of spinel Zn-ferrites. Then, they presented remarkable applications as electrodes in supercapacitors, which were thoroughly and critically discussed. The spinel Zn-ferrites nanocorals supercapacitor showed a much higher maximum specific capacitance (2031.81 F g-1 at a current density of 1 A g-1) than Fe2O3 and ZnO counterparts prepared by a similar approach (189.74 and 24.39 F g-1 at a current density of 1 A g-1). Its cyclic stability was also scrutinized via galvanostatic charging/discharging and electrochemical impedance spectroscopy, indicating excellent long-term stability. In addition, we manufactured an asymmetric supercapacitor device, which offered a high energy density value of 18.1 Wh kg-1 at a power density of 2609.2 W kg-1 (at 1 A g-1 in 2.0 mol L-1 KOH electrolyte). Based on our findings, we believe that higher performances observed for spinel Zn-ferrites nanocorals could be explained by their unique crystal structure and electronic configuration based on crystal field stabilization energy, which provides an electrostatic repulsion between the d electrons and the p orbitals of the surrounding oxygen anions, creating a level of energy that determines their final supercapacitance then evidenced, which is a very interesting property that could be explored for the production of clean energy storage devices.

Newly Synthesized CoFe2-xDyxO4 (x = 0; 0.1; 0.2; 0.4) Nanoparticles Reveal Promising Anticancer Activity against Melanoma (A375) and Breast Cancer (MCF-7) Cells.

The current study focuses on the synthesis via combustion of dysprosium-doped cobalt ferrites that were subsequently physicochemically analyzed in terms of morphological and magnetic properties. Three types of doped nanoparticles were prepared containing different Dy substitutions and coated with HPGCD for higher dispersion properties and biocompatibility, and were later submitted to biological tests in order to reveal their potential anticancer utility. Experimental data obtained through FTIR, XRD, SEM and TEM confirmed the inclusion of Dy3+ ions in the nanoparticles' structure. The size of the newly formed nanoparticles ranged between 20 and 50 nm revealing an inverse proportional relationship with the Dy content. Magnetic studies conducted by VSM indicated a decrease in remanent and saturation mass magnetization, respectively, in Dy-doped nanoparticles in a direct proportionality with the Dy content; the decrease was further amplified by cyclodextrin complexation. Biological assessment in the presence/absence of red light revealed a significant cytotoxic activity in melanoma (A375) and breast (MCF-7) cancer cells, while healthy keratinocytes (HaCaT) remained generally unaffected, thus revealing adequate selectivity. The investigation of the underlying cytotoxic molecular mechanism revealed an apoptotic process as indicated by nuclear fragmentation and shrinkage, as well as by Western blot analysis of caspase 9, p53 and cyclin D1 proteins. The anticancer activity for all doped Co ferrites varied was in a direct correlation to their Dy content but without being affected by the red light irradiation.

Optimisation of the Flame Spheroidisation Process for the Rapid Manufacture of Fe3O4-Based Porous and Dense Microspheres.

The rapid, single-stage, flame-spheroidisation process, as applied to varying Fe3O4:CaCO3 powder combinations, provides for the rapid production of a mixture of dense and porous ferromagnetic microspheres with homogeneous composition, high levels of interconnected porosity and microsphere size control. This study describes the production of dense (35-80 µm) and highly porous (125-180 µm) Ca2Fe2O5 ferromagnetic microspheres. Correlated backscattered electron imaging and mineral liberation analysis investigations provide insight into the microsphere formation mechanisms, as a function of Fe3O4/porogen mass ratios and gas flow settings. Optimised conditions for the processing of highly homogeneous Ca2Fe2O5 porous and dense microspheres are identified. Induction heating studies of the materials produced delivered a controlled temperature increase to 43.7 °C, indicating that these flame-spheroidised Ca2Fe2O5 ferromagnetic microspheres could be highly promising candidates for magnetic induced hyperthermia and other biomedical applications.

Simultaneous Enhancement of Magnetothermal and Photothermal Responses by Zn, Co Co-Doped Ferrite Nanoparticles.

Reducing nanoparticle (NP) dosage for hyperthermia therapy has remained a great challenge. In this work, efficiencies of alternating current (AC) magnetic field and near-infrared (NIR) heating are simultaneously enhanced by Zn and Co co-doping of magnetite NPs. The optimum magnetic anisotropy for maximized loss power under each magnetic field is achieved by tuning the doping concentration. The specific loss power of Zn0.3 Co0.08 Fe2.62 O4 @SiO2 NPs reaches 2428 W g-1 under an AC field of 27 kA m-1 at 430 kHz; 12 296 W g-1 under NIR laser irradiation at 808 nm and 2.5 W cm-2 ; and an unprecedented value of 14 724 W g-1 under dual mode. These values far exceed what has been achieved previously in iron oxide NPs. Ex vivo experiments on sacrificial mice show that while the NP dosage is substantially reduced to that used for magnetic resonance imaging, the surface body temperature of the mice reaches 50 °C after exposure to both AC field and laser irradiation under field parameters and laser intensity below safety limits. This nanoplatform is thus promising for multi-modal local hyperthermia therapy.

Effect of cation configuration and solvation on the band positions of zinc ferrite (100).

Zinc ferrite ZnFe[Formula: see text]O[Formula: see text] belongs to the spinel-type ferrites that have been proposed as photocatalysts for water splitting. The electronic band gap and the band edge positions are of utmost importance for the efficiency of the photocatalytic processes. We, therefore, calculated the absolute band energies of the most stable surface of ZnFe[Formula: see text]O[Formula: see text], the Zn-terminated (100) surface at self-consistent hybrid density functional theory level. The effect of Fe- and Zn-rich environments, cation exchange as antisite defects and implicit solvation on the band positions is investigated. Calculated flat band potentials of the pristine surface model ranges from [Formula: see text] to [Formula: see text] V against SHE in vacuum. For Zn-rich (Fe-rich) models this changes 0.3-0.9 (0.0-0.7) V against SHE. Fe-rich models are closest to the experimental range of reported flat band potentials. Solvent effects lower the calculated flat band potentials by up to 1.8 eV. The calculated band gaps range from 1.5 to 2.9 eV in agreement with previous theoretical work and experiment. Overall, our calculations confirm the experimentally observed low activity of ZnFe[Formula: see text]O[Formula: see text] and its dependence on preparation conditions.

Microwave assisted hydrothermally synthesized cobalt doped zinc ferrites nanoparticles for the degradation of organic dyes and antimicrobial applications.

A novel photocatalyst based cobalt doped zinc ferrites nanoparticles (Co-ZnFe2O4 NPs) was prepared to actively concentrate degradation of organic dyes in water. The aim this study is to investigate the effect of substitution of Co2+ for Zn2+ in zinc ferrites nanoparticles and is characterized with UV-visible spectroscopy, XRD, TEM, SEM, Photoluminescence and Vibrating sample magnetometer technique. When the calcinations temperature increases from 150 °C to 450 °C the amorphous ferrites begins to vanish and the characteristic reflections of cubic spinal Co-ZnFe2O4 phase are only observed at 450 °C. The band gap energy (Eg) of sample calcined at 250 °C is calculated at 5.2 eV and that of 450 °C is 4.5 eV. The observed value of band gap energy decreased with increasing calcinations temperature in the samples. The increase in PL peak intensity is due to collective emissions and light-scattering. The doping material, cobalt substitution at spinel zinc ferrites surface, and hence gradually decrease the amorphous effect, increase the saturation magnetization and decrease the coercivity while increasing the temperature. The compounds calcined at 250 °C and 450 °C were investigated for their in vitro antimicrobial activity against Staphylococcus aureus. A sample with 450 °C calcination temperature leads to higher efficiencies in the inhibition of growth of bacteria and degradation of organic dyes. Hence, this study provides a novel photocatalyst of Co-ZnFe2O4 NPs in the tile to degrade and analyze the environmentally ignored organic compounds.

Coal fly ash supported CoFe2O4 nanocomposites: Synergetic Fenton-like and photocatalytic degradation of methylene blue.

Rapid industrialization is causing a serious threat for the environment. Therefore, this research was aimed in developing ceramic cobalt ferrite (CoFe2O4) nanocomposite photocatalyst coated with coal fly ash (CFA-CoFe2O4) using facile hydrothermal synthesis route and their applications against methylene blue. The pristine cobalt ferrite photocatalyst was also prepared, characterized, and applied for efficiency comparison. Prepared photocatalyst were characterized by X-ray diffraction (XRD), fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Optical response of catalysts was check using photoluminescence spectroscopy (PL). pH drift method was used for the surface charge characteristics of the material under acidic and basic conditions of solution pH. The photocatalytic degradation potential of all the materials were determined under ultra-violet irradiations. The influencing reaction parameters like pH, catalyst dose, oxidant dose, dye concentration, and irradiation time, were sequentially optimized to obtain best suited conditions. The 99% degradation of 10 ppm methylene blue was achieved within 60 min of reaction time under pH = 5 and 7, catalyst dose = 10 and 12 mg/100 mL, oxidant = 12 mM and 5 mM for cobalt ferrite and CFA-CoFe2O4 photocatalysts, respectively. Afterwards, the radical scavenging experiments were conducted to find out the effective radical scavengers (˙OH, h+, and e-) in photocatalytic degradation process. The kinetic study of the process was done by applying 1st order, 2nd order, and BMG models. Statistical assessment of interaction effect among experimental variables was achieved using response surface methodology (RSM).

UV light assisted photocatalytic degradation of textile waste water by Mg0.8-xZnxFe2O4 synthesized by combustion method and in-vitro antimicrobial activities.

In this paper, Magnesium Zinc Ferrite (MZF) nanoparticles (Mg0.8-xZnxFe2O4, where x = 0.2, 0.4 and 0.6) are successfully fabricated by combustion process. The prepared nanoparticles are characterized through XRD, FTIR, UV, SEM, EDS and TEM. It has been confirmed that the samples produced cubic spinel structure with crystal size in the range of 13-15 nm. From the ultraviolet spectrum, the optical band gap is calculated which ranges from 5.6 to 4.6 eV. TEM micrographs confirm the nanocrystalline nature of combustion derived ferrite nanoparticles with average particle diameter of 7-28 nm. Antibacterial studies confirmed that the nanoparticles are toxic to Pseudomonas aeruginosa consists of greatest zone of inhibition of 25 mm. The antibacterial and photocatalytic studies exhibited improved activity which is strongly influenced by the zinc doping. Photocatalytic degradation study reveal that the prepared nanoparticles function as perfect catalyst for degradation of Methylene Blue (MB) dye and Textile Dyeing Waste Water (TDWW) under UV light, thus revealing their potential usage on organic pollutants.

Doping Independent Work Function and Stable Band Gap of Spinel Ferrites with Tunable Plasmonic and Magnetic Properties.

Tuning optical or magnetic properties of nanoparticles, by addition of impurities, for specific applications is usually achieved at the cost of band gap and work function reduction. Additionally, conventional strategies to develop nanoparticles with a large band gap also encounter problems of phase separation and poor crystallinity at high alloying degree. Addressing the aforementioned trade-offs, here we report Ni-Zn nanoferrites with energy band gap (Eg) of ≈3.20 eV and a work function of ≈5.88 eV. While changes in the magnetoplasmonic properties of the Ni-Zn ferrite were successfully achieved with the incorporation of bismuth ions at different concentrations, there was no alteration of the band gap and work function in the developed Ni-Zn ferrite. This suggests that with the addition of minute impurities to ferrites, independent of their changes in the band gap and work function, one can tune their magnetic and optical properties, which is desired in a wide range of applications such as nanobiosensing, nanoparticle based catalysis, and renewable energy generation using nanotechnology.

Coexistence and Coupling of Multiple Charge Orderings and Spin States in Hexagonal Ferrite.

The coupling between charge and spin orderings in strongly correlated systems plays a crucial role in fundamental physics and device applications. As a candidate of multiferroic materials, LuFe2O4 with a nominal Fe2.5+ valence state has the potential for strong charge-spin interactions; however, these interactions have not been fully understood until now. Here, combining complementary characterization methods with theoretical calculations, two types of charge orderings with distinct magnetic properties are revealed. The ground states of LuFe2O4 are decided by the parallel/antiparallel coupling of both charge and spin orderings in the adjacent FeO double layers. Whereas the ferroelectric charge ordering remains ferrimagnetic below 230 K, the antiferroelectric ordering undergoes antiferromagnetic-ferrimagnetic-paramagnetic transitions from 2 K to room temperature. This study demonstrates the unique aspects of strong spin-charge coupling within LuFe2O4. Our results shed light on the coexistence and competing nature of orderings in quantum materials.

Oxidative Precipitation Synthesis of Calcium-Doped Manganese Ferrite Nanoparticles for Magnetic Hyperthermia.

Superparamagnetic nanoparticles are of high interest for therapeutic applications. In this work, nanoparticles of calcium-doped manganese ferrites (CaxMn1-xFe2O4) functionalized with citrate were synthesized through thermally assisted oxidative precipitation in aqueous media. The method provided well dispersed aqueous suspensions of nanoparticles through a one-pot synthesis, in which the temperature and Ca/Mn ratio were found to influence the particles microstructure and morphology. Consequently, changes were obtained in the optical and magnetic properties that were studied through UV-Vis absorption and SQUID, respectively. XRD and Raman spectroscopy studies were carried out to assess the microstructural changes associated with stoichiometry of the particles, and the stability in physiological pH was studied through DLS. The nanoparticles displayed high values of magnetization and heating efficiency for several alternating magnetic field conditions, compatible with biological applications. Hereby, the employed method provides a promising strategy for the development of particles with adequate properties for magnetic hyperthermia applications, such as drug delivery and cancer therapy.

Magnetic NiFe2 O4 Nanoparticles Prepared via Non-Aqueous Microwave-Assisted Synthesis for Application in Electrocatalytic Water Oxidation.

Phase-pure spinel-type magnetic nickel ferrite (NiFe2 O4 ) nanocrystals in the size range of 4 to 11 nm were successfully synthesized by a fast and energy-saving microwave-assisted approach. Size and accessible surface areas can be tuned precisely by the reaction parameters. Our results highlight the correlation between size, degree of inversion, and magnetic characteristics of NiFe2 O4 nanoparticles, which enables fine-tuning of these parameters for a particular application without changing the elemental composition. Moreover, the application potential of the synthesized powders for the electrocatalytic oxygen evolution reaction in alkaline media was demonstrated, showing that a low degree of inversion is beneficial for the overall performance. The most active sample reaches an overpotential of 380 mV for water oxidation at 10 mA cm-2 and 38.8 mA cm-2 at 1.7 V vs. RHE, combined with a low Tafel slope of 63 mV dec-1 .

Calcination-Free Synthesis of Well-Dispersed and Sub-10†nm Spinel Ferrite Nanoparticles as High-Performance Anode Materials for Lithium-Ion Batteries: A Case Study of CoFe2 O4.

Spinel ferrites are promising anode materials for lithium-ion batteries (LIBs) owing to their high theoretical specific capacities. However, their practical application is impeded by inherent low conductivity and severe volume expansion, which can be surpassed by increasing the surface-to-volume ratio of nanoparticles. Currently, most methods produce spinel ferrite nanoparticles with large size and severe aggregation, degrading their electrochemical performance. In this study, a low-temperature aminolytic route was designed to synthesize sub-10 nm CoFe2 O4 nanoparticles with good dispersion through carefully exploiting the reaction of acetates and oleylamine. The performance of CoFe2 O4 nanoparticles obtained by a traditional co-precipitation method was also investigated for comparison. This work demonstrates that CoFe2 O4 nanoparticles synthesized by the aminolytic route are promising as anode materials for LIBs. Besides, this method can be extended to design other spinel ferrites for energy storage devices with superior performance by simply changing the starting material, such as MnFe2 O4 , MgFe2 O4 , ZnFe2 O4 , and so on.

Mixed metal ferrite (Mn0.6Zn0.4Fe2O4) intercalated g-C3N4nanocomposite: efficient sunlight driven photocatalyst for methylene blue degradation.

Visible active mixed metal ferrite intercalated semiconductor photocatalyst Mn0.6Zn0.4Fe2O4/g-C3N4was prepared via facile hydrothermal and liquid assembly method for methylene blue (MB) dye degradation. The prepared samples were well characterized in term of their functional groups, crystallinity, elemental analysis, surface morphology using Fourier transform infrared spectroscopy, x-ray diffraction spectroscopy, energy dispersive x-ray, and scanning electron microscopy, respectively. The optical response of catalysts was checked by estimating the energy band gap (Eg) of semiconductor photocatalysts using UV-vis spectroscopy. The photoluminescence spectroscopy was also performed to estimate the reduction in emission intensity after insertion of g-C3N4into Mn0.6Zn0.4Fe2O4.The novel composition of Mn0.6Zn0.4Fe2O4with g-C3N4,improved the optical response of pristine photocatalysts due to the reduction in the energy band gap and insertion of heterojunction. The surface area analysis of Mn0.6Zn0.4Fe2O4and Mn0.6Zn0.4Fe2O4/g-C3N4were acquired by Brunauer-Emmett-Teller. Point zero charge was also determined to observe the surface behavior of composite under different solution pH. Various parameters such as pH, catalyst dose, oxidant dose, irradiation time and initial dye concentration were optimized, and their effects were studied in photo-Fenton process. It was observed that 98% MB dye was degraded under optimized conditions (pH = 8, composite dose = 50 mg/100 ml, oxidant dose = 7 mM, initial dye conc. = 10 ppm, and irradiation time = 120 min). The results showed that when the ferrites of mixed metals (Mn, Zn) were used with g-C3N4their photocatalytic activity enhanced due to mutual effect of both mixed metals ferrite and g-C3N4, which is considerably higher than their individual effect already reported. Furthermore, the combined effect of independent variables was evaluated by response surface methodology.

Anti-bacterial and wound healing-promoting effects of zinc ferrite nanoparticles.

BACKGROUND: Increasing antibiotic resistance continues to focus on research into the discovery of novel antimicrobial agents. Due to its antimicrobial and wound healing-promoting activity, metal nanoparticles have attracted attention for dermatological applications. This study is designed to investigate the scope and bactericidal potential of zinc ferrite nanoparticles (ZnFe2O4 NPs), and the mechanism of anti-bacterial action along with cytocompatibility, hemocompatibility, and wound healing properties. RESULTS: ZnFe2O4 NPs were synthesized via a modified co-precipitation method. Structure, size, morphology, and elemental compositions of ZnFe2O4 NPs were analyzed using X-ray diffraction pattern, Fourier transform infrared spectroscopy, and field emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. In PrestoBlue and live/dead assays, ZnFe2O4 NPs exhibited dose-dependent cytotoxic effects on human dermal fibroblasts. In addition, the hemocompatibility assay revealed that the NPs do not significantly rupture red blood cells up to a dose of 1000 µg/mL. Bacterial live/dead imaging and zone of inhibition analysis demonstrated that ZnFe2O4 NPs showed dose-dependent bactericidal activities in various strains of Gram-negative and Gram-positive bacteria. Interestingly, NPs showed antimicrobial activity through multiple mechanisms, such as cell membrane damage, protein leakage, and reactive oxygen species generation, and were more effective against gram-positive bacteria. Furthermore, in vitro scratch assay revealed that ZnFe2O4 NPs improved cell migration and proliferation of cells, with noticeable shrinkage of the artificial wound model. CONCLUSIONS: This study indicated that ZnFe2O4 NPs have the potential to be used as a future antimicrobial and wound healing drug.