Experimental investigation of zinc ferrite/insulation oil nanofluid natural convection heat transfer, AC dielectric breakdown voltage, and thermophysical properties.

Improving the thermal and dielectric properties of insulation oil (INO) with nanoadditives is an important challenge, and achieving dispersion stability in these nanofluids is quite challenging, necessitating further investigation. The main goal of this study is the synthesis and use of the hydrophobicity of zinc ferrite (ZnFe2O4) nanoparticles, which can improve both the thermal and dielectric properties of the INO. This oil is made from distillate (petroleum), including severely hydrotreated light naphthenic oil (75-85%) and severely hydrotreated light paraffinic oil (15-25%). A comprehensive investigation was carried out, involving the creation of nanofluids with ZnFe2O4 nanoparticles at various concentrations, and employing various characterization methods such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR), scanning electron microscopy, energy dispersive X-ray (EDX), zeta potential analysis, and dynamic light scattering (DLS). The KD2 Pro thermal analyzer was used to investigate the thermal characteristics, including the thermal conductivity coefficient (TCC) and volumetric heat capacity (VHC). Under free convection conditions, the free convection heat transfer coefficient (FCHTC) and Nusselt numbers (Nu) were evaluated, revealing enhancements ranging from 14.15 to 11.7%. Furthermore, the most significant improvement observed in the AC Breakdown voltage (BDV) for nanofluids containing 0.1 wt% of ZnFe2O4 amounted to 17.3%. The most significant finding of this study is the improvement in the heat transfer performance, AC BDV, and stability of the nanofluids.

"Three-in-One": Ultrasensitive Lateral Flow Immunoassay Driven by Magnetic Enrichment and Photothermal Signal Amplification.

Conventional lateral flow immunoassay (LFIA) usually suffers from poor antimatrix interference, unsatisfactory sensitivity, and lack of quantitative ability for target analyte detection in food matrices. In response to these limits, here, multifunctional nanomaterial ZnFe2O4 nanoparticles (ZFOs) were developed and integrated into LFIA for powerful magnetic separation/enrichment and colorimetric/photothermal target sensing. Under optimum conditions, the detection for clenbuterol (CL) with magnetic enrichment achieves 9-fold higher sensitivity compared to that without enrichment and 162-fold higher sensitivity compared to that based on traditional colloidal golds. Attributing the improved performances of ZFOs, CL can be detected at ultralow levels in pork and milk with 10 min of immunoreaction time. The vLODs were 0.01 µg kg-1 for two modes, and the cutoff values of CL were about 5 and 3 µg kg-1, respectively. More importantly, the enrichment ZFO-mediated LFIA (ZE-LFIA) exhibits a similar limit of detection (LOD) in both buffer solution and food matrix, demonstrating a universal resistance to the food matrix. The multitudinous performance merits of this ZE-LFIA with high sensitivity, matrix tolerance, accuracy, and specificity have ensured a broad application potential for target detection of clenbuterol and can serve as an experience for other veterinary drug residues' detection.

Unveiling the synergy: Biocompatible alginate-cellulose hydrogel loaded with silk fibroin and zinc ferrite nanoparticles for enhanced cell adhesion, and anti-biofilm activity.

Combining a biocompatible hydrogel scaffold with the cell-supportive properties of silk fibroin (SF) and the unique functionalities of ZnFe2O4 nanoparticles creates a promising platform for advanced nanobiomaterials. The research is centered on synthesizing a natural hydrogel using cellulose (Cellul) and sodium alginate (SA) combined with SF and zinc ferrite nanoparticles. A range of analytical and biological assays were conducted to determine the biological and physicochemical properties of the nanobiocomposite. The hemolysis and 2,5-diphenyl-2H-tetrazolium bromide (MTT) assays indicated that the SA-Cellul hydrogel/SF/ZnFe2O4 nanobiocomposite was a biocompatible against human dermal fibroblasts (Hu02) and red blood cells (RBC). In addition, aside from demonstrating outstanding anti-biofilm activity, the nanobiocomposite also promotes the Hu02 cells adhesion, showcasing the synergistic effect of incorporating SF and ZnFe2O4 nanoparticle. These promising results show that this nanobiocomposite has potential applications in various biomedical fields.

Formulation of biodegradable alginate-based nano-carriers for in-vitro drug delivery and antibacterial activity.

Evaluation of the controlled release of ciprofloxacin (CIP.HCl) and the antibacterial efficacy of alginate (ALG)-based nanocarriers constitute the primary objectives of the current work. Herein, ALG-based nano-structures were prepared by the co-precipitation method and thoroughly analyzed using different characterization techniques, i.e., fourier transform infrared (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and zeta potential (ZP). The intense peaks emerged at 500, 545, and 750 cm-1 due to the CeO bond. Peaks that appeared at 550-600 cm-1 and 525 cm-1 are due to the stretching vibrations of FeO and ZnO bonds, respectively. Lowering of the peaks from 1640 to 1630 cm-1 and 1420 to 1384 cm-1 were observed in ALG-based nanocomposite (NC) due to the interaction of ALG with metal oxides (MO), which confirmed the formulation of CeO2/ZnFe2O4/ALG nanocomposite. The diffraction peaks at 28.6°, 56.6°, 76.5°, 37°, 47.9°, 62.3°, 74°, 13°, 21° confirmed the synthesis of MO (crystallite size 15.74 nm) and CeO2/ZnFe2O4/ALG (12 nm). In accordance with morphological studies, CeO2/ZnFe2O4 oxides had a uniform distribution throughout the relatively smooth and permeable surface of the ALG-based NC. Ciprofloxacin (CIP) was used as a model drug. Negative values of ZP revealed that CIP-loaded nanocomposite (CeO2/ZnFe2O4/ALG/CIP) had more stability than CeO2/ZnFe2O4/ALG. The maximum percentage of loading around 25 % on ALG NC was examined using the optical density (OD) method at pH 5.5. Correlation coefficients from the first order (0.971), Korsmeyer (0.9858), and Hixson (0.9021) models show the best-fitted models of the release profile in all circumstances. The release mechanism was investigated using various kinetics models. The controlled drug released was observed around 17 % at 40 °C after 3 h at pH 7.4, which is almost identical to the body temperature of a human, which is 37 °C. Similarly, after 24 h, sustained and controlled in-vitro release of the drug was studied, and it was 37, 72, and 74 % at pH 2.2, 7.4, and 9.4, respectively. Thus, prepared ALG-based NC is suitable for the controlled in-vitro release of (CIP.HCl). Metal oxides (CeO2/ZnFe2O4) and ALG-based nanocomposite (CeO2/ZnFe2O4/ALG) showed great antibacterial activity against Staphylococcus aureus (S. aureus) like 15 mm and 14 mm than Escherichia coli (E. coli).

Harnessing solar power for enhanced photocatalytic degradation of coloured pollutants using novel Mg-doped-ZnFe2O4/S@g-C3N4 heterojunction: A facile hydrothermal synthesis approach.

The ability of heterogeneous photocatalysis to effectively remove organic pollutants from wastewater has shown great promise as a tool for environmental remediation. Pure zinc ferrites (ZnFe2O4) and magnesium-doped zinc ferrites (Mg@ZnFe2O4) with variable percentages of Mg (0.5, 1, 3, 5, 7, and 9 mol%) were synthesized via hydrothermal route and their photocatalytic activity was checked against methylene blue (MB) taken as a model dye. FTIR, XPS, BET, PL, XRD, TEM, and UV-Vis spectroscopy were used for the identification and morphological characterization of the prepared nanoparticles (NPs) and nanocomposites (NCs). The 7% Mg@ZnFe2O4 NPs demonstrated excellent degradation against MB under sunlight. The 7% Mg@ZnFe2O4 NPs were integrated with diverse contents (10, 50, 30, and 70 wt.%) of S@g-C3N4 to develop NCs with better activity. When the NCs were tested to degrade MB dye, it was revealed that the 7%Mg@ZnFe2O4/S@g-C3N4 NCs were more effective at utilizing solar energy than the other NPs and NCs. The synergistic effect of the interface formed between Mg@ZnFe2O4 and S@g-C3N4 was primarily responsible for the boosted photocatalytic capability of the NCs. The fabricated NCs may function as an effective new photocatalyst to remove organic dyes from wastewater.

A waste-to-wealth conversion of plastic bottles into effective carbon-based adsorbents for removal of tetracycline antibiotic from water.

Currently, plastic waste and antibiotic wastewater are two of the most critical environmental problems, calling for urgent measures to take. A waste-to-wealth strategy for the conversion of polyethylene terephthalate (PET) plastic bottles into value-added materials such as carbon composite is highly recommended to clean wastewater contaminated by antibiotics. Inspired by this idea, we develop a novel PET-AC-ZFO composite by incorporating PET plastic-derived KOH-activated carbon (AC) with ZnFe2O4 (ZFO) particles for adsorptive removal of tetracycline (TTC). PET-derived carbon (PET-C), KOH-activated PET-derived carbon (PET-AC), and PET-AC-ZFO were characterized using physicochemical analyses. Central composite design (CCD) was used to obtain a quadratic model by TTC concentration (K), adsorbent dosage (L), and pH (M). PET-AC-ZFO possessed micropores (d ≈ 2 nm) and exceptionally high surface area of 1110 m2 g-1. Nearly 90% TTC could be removed by PET-AC-ZFO composite. Bangham kinetic and Langmuir isotherm were two most fitted models. Theoretical maximum TTC adsorption capacity was 45.1 mg g-1. This study suggested the role of hydrogen bonds, pore-filling interactions, and π-π interactions as the main interactions of the adsorption process. Thus, a strategy for conversion of PET bottles into PET-AC-ZFO can contribute to both plastic recycling and antibiotic wastewater mitigation.

Au- ZnFe2O4 hollow microspheres based gas sensor for detecting the mustard gas simulant 2-chloroethyl ethyl sulfide.

Mustard gas, a representative of blister agents, poses a severe threat to human health. Although the structure of 2-chloroethyl ethyl sulfide (2-CEES) is similar to mustard gas, 2-CEES is non-toxic, rendering it a commonly employed simulant in related research. ZnFe2O4-based semiconductor gas sensors exhibit numerous advantages, including structural stability, high sensitivities, and easy miniaturization. However, they exhibit insufficient sensitivity at low concentrations and require high operating temperatures. Owing to the effect of electronic and chemical sensitization, the gas-sensing performance of a sensor may be remarkably enhanced via the sensitization method of noble metal loading. In this study, based on the morphologies of ZnFe2O4 hollow microspheres, a solvothermal method was adopted to realize different levels of Au loading. Toward 1 ppm of 2-CEES, the gas sensor based on 2 wt.% Au-loaded ZnFe2O4 hollow microspheres exhibited a response sensitivity twice that of the gas sensor based on pure ZnFe2O4; furthermore, the response/recovery times decreased. Additionally, the sensor displayed excellent linear response to low concentrations of 2-CEES, outstanding selectivity in the presence of several common volatile organic compounds, and good repeatability, as well as long-term stability. The Au-loaded ZnFe2O4-based sensor has considerable potential for use in detecting toxic chemical agents and their simulants.

SnO2QDs sensitized ZnFe2O4spheres with enhanced acetone sensing performance.

Herein, SnO2QDs (<10 nm) with small size instead of conventional nanoparticles was employed to modify ZnFe2O4to synthesize porous and heterogeneous SnO2/ZnFe2O4(ZFSQ) composites for gas sensing. By an immersion process combined with calcination treatment, the resultant porous ZFSQ composites with different contents of SnO2QDs were obtained, and their sensing properties were investigated. Compared with bare ZnFe2O4and SnO2QDs, porous ZFSQ composites based-sensors showed much improved sensor response to acetone. For contrast, the sensor performance of ZFSQ composites was also compared with that of ZnFe2O4sphere modified by SnO2nanoparticles with different size. The porous ZFSQ composite with 5 wt% SnO2QDs (ZFSQ-5) showed a better acetone sensing response than that of other ZFSQ composites, and it exhibited a high response value of 110-100 ppm of acetone and a low detection limit of 0.3 ppm at 240 °C. In addition to the rich heterojunctions and porous structure, the size effect of SnO2QDs was other indispensable reasons for the improved sensor performance. Finally, the ZFSQ-5 composite sensor was attempted to be applied for acetone sensing in exhaled breath, suggesting its great potential in monitoring acetone.

Oxygen Vacancy-Rich Bimetallic Au@Pt Core-Shell Nanosphere-Functionalized Electrospun ZnFe2O4 Nanofibers for Chemiresistive Breath Acetone Detection.

Sensitive and selective acetone detection is of great significance in the fields of environmental protection, industrial production, and individual health monitoring from exhaled breath. To achieve this goal, bimetallic Au@Pt core-shell nanospheres (BNSs) functionalized-electrospun ZnFe2O4 nanofibers (ZFO NFs) are prepared in this work. Compared to pure NFs-650 analogue, the ZFO NFs/BNSs-2 sensor exhibits a stronger mean response (3.32 vs 1.84), quicker response/recovery speeds (33 s/28 s vs 54 s/42 s), and lower operating temperature (188 vs 273 °C) toward 0.5 ppm acetone. Note that an experimental detection limit of 30 ppb is achieved, which ranks among the best cases reported thus far. Besides the demonstrated excellent repeatability, humidity-enhanced response, and long-term stability, the selectivity toward acetone is remarkably improved after BNSs functionalization. Through material characterizations and DFT calculations, all these improvements could be attributed to the boosted oxygen vacancies and abundant Schottky junctions between ZFO NFs and BNSs, and the synergistic catalytic effect of BNSs. This work offers an alternative strategy to realize selective subppm acetone under high-humidity conditions catering for the future requirements of noninvasive breath diabetes diagnosis in the field of individual healthcare.

ZnFe2O4@SiO2@L-lysine@SO3H: preparation, characterization, and its catalytic applications in the oxidation of sulfides and synthesis of Bis(pyrazolyl)methanes.

Herein, we report the synthesis of ZnFe2O4@SiO2@L-lysine@SO3H as a green, novel magnetic nanocatalyst, containing the sulfuric acid catalytic sites on the surface of zinc ferrite as the catalytic support. The physical and chemical properties of raw and modified samples (ZnFe2O4@SiO2@L-lysine@SO3H) were characterized by TGA, EDX, PXRD, Map, and FTIR analyses. The prepared nanocatalyst has excellent catalytic activity in synthesizing the oxidation of sulfides to the sulfoxides and Synthesis of pyrazolyl (Bis(pyrazolyl)methane) derivatives under green conditions. This designed nanocatalyst offers several advantages including the use of inexpensive materials and high yield, simple procedure, and commercially available. The synthesized mesoporous nanocatalyst was recovered and reused in five continuous cycles without considerable change in its catalytic activity.

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-carboxanilide method. 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.

Synthesis of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite as a superior and reusable heterogeneous catalyst for the preparation of pyrimidine derivatives and investigation of their antimicrobial activities.

In this report, we synthesized some pyrimidine derivatives by multi-component reaction of urea, benzaldehydes, and 1,3-indandione in the presence of ZIF-8/ZnFe2O4/GO-OSO3H nanocomposite under reflux conditions. Initially, graphene oxide was prepared from graphite, and then it was sulfonated using ClOSO3H. Next, GO-OSO3H nanosheets were used to support ZIF-8/ZnFe2O4 nanostructure. The construction of the synthesized structure was established using different spectral techniques such as X-ray crystallography (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX/Mapping), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The present method provides various benefits including the efficiency of outcomes, easy separation of the catalyst, and excellent yield of the products within short reaction times. Moreover, the antibacterial activities of pyrimidine derivatives were investigated via the agar-well diffusion method on gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria and the obtained results illustrated reasonable effects.

Discerning the catalytic treatment of cationic dye wastewater in photoreactor comprising ternary (Co3+/Co2+)-embedded SnO2/ZnFe2O4 composite sensitive toward ultra-violet illumination.

Herein, magnetic (Co3+/Co2+)-integrated SnO2, SnO2/ZnFe2O4, and ZnFe2O4 composites have been prepared from triply distilled water and 30% of isopropanol in the water medium. The phase evolution, microstructure, and magnetism were investigated successfully and tested for cationic dye wastewater degradation containing Rhodamine 6G and Methylene Blue under ultra-violet irradiation. Composite spheres are attributed to efficient heterojunction interfaces between ZnFe2O4 and SnO2 semiconductors with the support of (Co3+/Co2+) nanoparticles. The results provide a simple, low-cost, environmentally friendly, and scalable method of ternary composites to degrade mixed dyes. Co3+/Co2+-implanted SnO2/ZnFe2O4 offered narrowed bandgap energy, more light absorption, diminishing electron-hole recombination, and more charge carriers toward cationic dye wastewater than the binary components. The rate constant of Rhodamine 6G degradation was observed at 0.0237 min-1, and Methylene Blue degradation was observed at 0.0187 min-1 at 90 min under UV (λ = 365 nm) irradiation. Capturing studies of various organic reactive species and mechanisms of composites was also proposed in detail.

Preparation of Fe@Fe3O4/ZnFe2O4 Powders and Their Consolidation via Hybrid Cold-Sintering/Spark Plasma-Sintering.

Our study is focused on optimizing the synthesis conditions for the in situ oxidation of Fe particles to produce Fe@Fe3O4 core-shell powder and preparation via co-precipitation of ZnFe2O4 nanoparticles to produce Fe@Fe3O4/ZnFe2O4 soft magnetic composites (SMC) through a hybrid cold-sintering/spark plasma-sintering technique. XRD and FTIR measurements confirmed the formation of a nanocrystalline oxide layer on the surface of Fe powder and the nanosized nature of ZnFe2O4 nanoparticles. SEM-EDX investigations revealed that the oxidic phase of our composite was distributed on the surface of the Fe particles, forming a quasi-continuous matrix. The DC magnetic characteristics of the composite compact revealed a saturation induction of 0.8 T, coercivity of 590 A/m, and maximum relative permeability of 156. AC magnetic characterization indicated that for frequencies higher than 1 kHz and induction of 0.1 T, interparticle eddy current losses dominated due to ineffective electrical insulation between neighboring particles in the composite compact. Nevertheless, the magnetic characteristics obtained in both DC and AC magnetization regimes were comparable to those reported for cold-sintered Fe-based SMCs.

Synthesize magnetic ZnFe2O4@C/Cd0.9Zn0.1S catalysts with S-scheme heterojunction to achieve extraordinary hydrogen production efficiency.

Suppressing the electron-hole recombination rate of catalyst legitimately is one of the effective strategies to improve photocatalytic hydrogen evolution. Herein, carbon-coated metal oxide, ZnFe2O4@C (ZFO@C), nanoparticles were synthesized and employed to couple with quadrupedal Cd0.9Zn0.1S (CZS) via an ordinary ultrasonic self-assembly method combined with calcination to form a novel ZFO@C/CZS catalyst with step-scheme (S-scheme) heterojunction. The photocatalytic hydrogen evolution reaction (HER) was conducted to verify the enhanced photoactivity of ZFO@C/CZS. The optimal ZFO@C/CZS exhibits an extraordinary photocatalytic HER rate of 111.3 ± 0.9 mmol g-1 h-1 under visible-light irradiation, corresponding to an apparent quantum efficiency as high as (76.2 ± 0.9)% at 450 nm. Additionally, the as-synthesized ZFO@C/CZS composite exhibits high stability and recyclability. The excellent photocatalytic hydrogen evolution performance should arise from the formed S-scheme heterojunction and the unique ZFO@C core-shell structure, which inhibit electron hole recombination as well as provide more reactive sites. The pathway of S-scheme charge transfer was validated through density functional theory calculations and electrochemical measurements. This work provides a rational strategy for the synthesis of unique magnetic S-scheme heterojunction photocatalysts for water splitting under visible light irradiation.

Wrinkle Structure Regulating Electromagnetic Parameters in Constructed Core-shell ZnFe2O4@PPy Microspheres as Absorption Materials.

Structure engineering of magnetic-dielectric multi-components is emerging as an effective approach for presuming high-performance electromagnetic (EM) absorption, but still faces bottlenecks due to the ambiguous regulation mechanism of surface morphology. Here, a novel wrinkled surface structure is tailored on the ZnFe2O4 microsphere via a spray-pyrolysis induced Kirkendall diffusion effect, the conductivity of the sample is affected, and a better impedance matching is adjusted by modulating the concentration of metal nitrate precursors. Driven by a vapor phase polymerization, conductive polypyrrole (PPy) shell are in situ decorated on the ZnFe2O4 microsphere surfaces, ingeniously constructing a core-shell ZnFe2O4@PPy composites. Moreover, a systematic investigation reveals that this unique wrinkled surface structure is highly dependent on the metal salt concentration. Optimized wrinkle ZnFe2O4@PPy composite exhibits a minimum reflection loss (RLmin) reached -41.0 dB and the effective absorption bandwidth (EAB) can cover as wide as 4.1 GHz. The enhanced interfacial polarization originated from high-density ZnFe2O4-PPy heterostructure, and the conduction loss of PPy contributes to the boosted dielectric loss capability. This study gives a significant guidance for preparing high-performance EM composites by tailoring the surface wrinkle structure.

Anti-cancer Application of Nat-ZnFe2O4 Nanoparticles on 2D Tumor Models.

Metal/Metal Oxide nanoparticles (M/MO NPs) exhibit potential biomedical applications due to their tunable physicochemical properties. Recently, the biogenic synthesis of M/MO NPs has gained massive attention due to their economical and eco-friendly nature. In the present study, Nyctanthes arbor-tristis (Nat) flower extract-derived Zinc Ferrite NPs (Nat-ZnFe2O4 NPs) were synthesized and physicochemically characterized by FTIR, XRD, FE-SEM, DLS, and other instruments to study their crystallinity, size, shape, net charge, presence of phytocompounds on NP's surface and several other features. The average particle size of Nat-ZnFe2O4 NPs was approx. 25.87 ± 5.67 nm. XRD results showed the crystalline nature of Nat-ZnFe2O4 NPs. The net surface charge on NPs was -13.28 ± 7.18 mV. When tested on mouse fibroblasts and human RBCs, these NPs were biocompatible and hemocompatible. Later, these Nat-ZnFe2O4 NPs exhibited potent anti-neoplastic activity against pancreatic, lung, and cervical cancer cells. In addition, NPs induced apoptosis in tested cancer cells through ROS generation. These in vitro studies confirmed that Nat-ZnFe2O4 NPs could be used for cancer therapy. Moreover, further studies are recommended on ex vivo platforms for future clinical applications.

Boosting the catalytic activity of nanostructured ZnFe2O4 spinels incorporating with Cu2+ for photo-Fenton degradation under visible light.

Methylene blue (MB) is hazardous in natural water because this dye causes serious diseases that endangers public health and ecosystems. Photocatalytic degradation is a prominent technique for achieving the effective elimination of dye pollutants from wastewater and contribute vitally to ecology and environmental safety. Herein, Cu2+-substituted ZnFe2O4 nanomaterials (CuxZn1-xFe2O4; x = 0, 0.1, 0.2, 0.3, 0.4, 0.6) were synthesized, characterized, and applied for the photocatalytic degradation of MB dye beneath visible light with the assistance of hydrogen peroxide (H2O2). The feature of the photo-catalysts was determined by XRD, EDX, FTIR, DRS, BET, SEM, and TEM techniques. Incorporation of Cu2+ ions changed the crystalline phase, particle size, morphology, and surface area. The photocatalysis condition was optimized with the following major factors, the amout of doping Cu2+ ions, H2O2 concentration, adsorbent dosage, and MB concentration. As a result, the photocatalytic MB degradation efficiency by Cu0.6Zn0.4Fe2O4 catalyst was 99.83% within 90 min under LED light (λ ≥ 420 nm), which was around 4 folds higher than that of pure ZnFe2O4. The photo-Fenton kinetics were in accordance with the pseudo-first-order kinetic model (R2 = 0.981), giving the highes rate constant of 0.034 min-1. It can be, therefore, concluded that Cu2+ substitution considerably boosted the photocatalytic activity of CuxZn1-xFe2O4 ZnFe2O4, suggesting a bright prospect of Cu0.6Zn0.4Fe2O4 as a photo-catalyst in the dyes wastewater treatment.

Synthesis of ZnFe2O4 Nanospheres with Tunable Morphology for Lithium Storage.

ZnFe2O4 (ZFO) nanospheres with complex structures have been synthesized by a one-step simple solvothermal method using two different types of precursors-metal chlorides and nitrates -and were fully characterized by XRD, SEM, XPS, and EDS. The ZFO nanospheres synthesized from chloride salts (ZFO_C) were loose with a size range of 100-200 nm, while the ZFO nanospheres synthesized from nitrate salts (ZFO_N) were dense with a size range of 300-500 nm but consisted of smaller nanoplates. The different morphologies may be caused by the different hydrolysis rates and different stabilizing effects of chloride and nitrate ions interacting with the facets of forming nanoparticles. Electrochemical tests of nitrate-based ZFO nanospheres as anode materials for lithium-ion batteries demonstrated their higher cyclic stability. The ZFO_C and ZFO_N samples have initial specific discharge/charge capacities of 1354/1020 and 1357/954 mAh∙g-1, respectively, with coulombic efficiencies of 75% and 71%. By the 100th cycle, ZFO_N has a capacity of 276 mAh∙g-1, and for ZFO_C, only 210 mAh∙g-1 remains after 100 cycles.

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.