Papers by Keyword: Zinc Ferrite

Abstract: The antibiotic pollutant treatment in wastewater using conventional method remains a challenge. One of the most fluoroquinolone antibiotics family used by human and animal cure is ciprofloxacin (CIP). CIP has exhibited as a recalcitrant compound in nature with concentration from ng to mg. To overcome this issue, recent technologies have applied such as photocatalysis technology for water decontamination. Furthermore, photocatalyst materials that used in this research were zinc ferrite and graphitic carbon nitride. A simple hydrothermal-coprecipitation method has succeed to synthesis zinc ferrite. While, unexfoliated graphitic carbon nitride (ZFO@ue-CN) was synthesized by calcination at 550 °C for 4 h under air condition. A heterostructure approach combining zinc ferrite and unexfoliated graphitic carbon nitride (ZFO@ue-CN) has been investigated as a potential solution. In this study, a ZFO@ue-CN was constructed by calcination method under atmosphere condition at 400 °C for 2 h. The ZFO@ue-CN has been characterized involving structural, morphological, and optical. Furthermore, ZFO@ue-CN exhibited excellent degradation performance with over 88% removal of ciprofloxacin. The heterojunction formation of ZFO@ue-CN nanocomposite provide more efficient electron transfer compared to single material. Combination between metal oxide@ue-CN can open up the new platform for simple material preparation, nevertheless it can keep the photodegradation performance. This result also emphasizes that the ZFO@ue-CN nanocomposites has prominent application for wastewater treatment.

Abstract: Ferrite is frequently employed as a high-efficiency microwave absorption material (MAM). Herein, a novel and prospective high-temperature mechanochemical (HTMC) method was employed to fabricate pure-phase spinel zinc ferrite powders with a spherical structure. After that, the chemical compositions and structures, microscopic morphology, static magnetic characteristics, and microwave absorption properties of the powders were examined. The powder achieves a minimum reflection loss of -54.7 dB at a matching thickness of 4.4 mm, at which time the effective absorption bandwidth approaches 3.9 GHz. The superior microwave absorption ability of the powders is attributable to the favorable cooperative impact between dielectric and magnetic losses. Therefore, the as-prepared zinc ferrite powders can be utilized as high-efficiency MAM. The HTMC method has considerable potential for the large-scale preparation of high-performance MAM.

Abstract: Herein, we report for the first time the thermal diffusivity of zinc ferrite/ silver/ silver chloride nanocomposite with a four-fold enhancement in comparison with the base fluid. A systematic analysis of the dependence of calcination temperature and synthesis routes on the crystallinity of nanocomposites of zinc ferrite with silver and silver chloride suiting it for diverse applications was done. Synthesized via the co-precipitation method, the samples were characterized using X-ray diffraction, Field emission scanning electron microscopy, Energy dispersive X-ray, Vibration sample magnetometer, ultraviolet-visible Diffusive Reflective spectroscopy and Photoluminescence studies. A zeta potential of -31.1mV was obtained for the sample showing good colloidal stability. The thermal diffusivity of the samples as nanofluids was analyzed using the dual beam thermal lens method. The study also envisages the magnetically retrievable and visible light-active nature of the synthesized samples indicating their suitability for photocatalytic degradation of toxic dyes. The work on photocatalytic degradation of methylene blue stands out in attaining rapid, efficient dye degradation of 98% within 90 minutes of sunlight exposure in comparison with unblended zinc ferrite nanoparticles even without any oxidizing agent.

Abstract: The ZnNd_(x)Fe_(2-x)O₄ (x = 0.0; 0.010; 0.020 and 0,030) systems were synthesized by solid reaction method from a mixture of ZnO₂, Fe₂O₃ and Nd₂O₃ powders according to their mole ratio using mechanical milling techniques. In this mixture was added ethanol of 25 ml and then milled for 5 hours, after that sintered at a temperature of 1000 °C for 5 hours. X-ray diffraction patterns showed that the Nd³⁺ ion substitution in ZnFe₂O₄ with the concentration of x = 0.0 to 0.02 did not result in changes in ZnFe₂O₄ phase with cubic structure (space group of Fd-3m). However, the composition of x = 0.030 formed multiphases ZnFe₂O₄ and NdFeO₃ phases. The morphological observation using Scanning Electron Microscope (SEM) showed spherical and uniform particles. Whereas the microwave absorption capability of the sample ZnNd_(x)Fe_(2-x)O₄ system increased with the increasing concentration of x from 91.20% up to 97.80% with the highest absorption is found at a frequency of 10.24 GHz. The dielectric loss of this study is very small around 0.005 up to 0.05. It is hoped that the compound ZnNd_0.02Fe_1,98O₄ can be applied to microwave absorbing agents at high frequencies (X-band range) in antiradar detection systems.

Abstract: An ammonium leaching of electric arc furnace dust (EAFD) was described in this paper. Ural steelmaking plants obtain EAFD of the following chemical composition, %: 23 Zn; 26 Fe; 10 Cl; 2,5 Ca; 2 Mg; 1,2 Pb; 1 Na. The most complete zinc extraction can be achieved with two-stages treatment by calcination of dusts [1], followed by leaching. The effect of calcination temperature (500-1000 °C), calcination time (1-4 hours) and Ca/Fe mass ratio on zinc extraction efficiency in ammonia solutions was studied. The optimal conditions were proposed to extract up to 87% zinc.

Abstract: When re-melting scrap in electric arc furnaces (EAF), dust is formed. This dust is a rich zinc-containing raw material. The composition of the EAF-dust from JSC “Pervouralsk New Pipe Plant” was investigated. Dust contains 18 wt.% of zinc, more than 1/3 of zinc is a part of the slightly soluble in acids and alkalis of zinc ferrite ZnFe₂O₄. The aim of the work is to study the effect of roasting temperatures of 700, 850 and 1000 °C and the effect of CaO and Na₂CO₃ additives on the decomposition of zinc ferrite. Thermodynamic analysis of chemical transformations in dust during roasting showed that the additions of CaO and Na₂CO₃ provide destruction of zinc ferrite and promote the transfer of zinc into the acid-soluble form of ZnO. The effect of the roasting temperature, the duration of roasting and the amount of calcium oxide and sodium carbonate additions on the degree of zinc transition into acid-soluble form was studied experimentally. The best results were obtained at 1000 oС. The increase in the roasting time in the interval from 1 to 3 hours promotes an increase in the concentration of acid-soluble zinc in the cinder. The combined additions of 36 wt.% of Na₂CO₃ and 19 wt.% of CaO above the dust mass are optimal. The proportion of acid-soluble zinc in the cinder increased to 97–99 %, as a result of roasting under optimal conditions.

Abstract: In order to improve TiO₂ photocatalytic activity ZnFe₂O₄/TiO₂ nanocomposites with different ZnFe₂O₄ mass loading were produced. Obtained ZnFe₂O₄ nanoparticles were coupled with TiO₂ via microwave-assisted hydrothermal method in order to improve photon absorption in a range of visible light. Prepared nanostructures were characterized with scanning electron microscopy and X-ray diffraction. Photocatalytic activity of prepared samples was investigated by degradation of methylene blue under different light sources – LED, Hg and Osram Vitalux lamps. ZnFe₂O₄ consists of spherical nanoparticles with average size of 15 nm. TiO₂ spherical nanoparticles size is in a range of 30÷45 nm. The results show that doping TiO₂ with ZnFe₂O₄ nanoparticles increases photocatalytic activity. Photocatalytic activity increases as mass loading of ZnFe₂O₄ decreases.

Abstract: The composites sample of Zinc Ferrite (Zn_xFe_3-xO₄) were prepared by mixing zinc oxide (ZnO) and iron oxide (Fe₂O₃) via different stoichiometry (ratio) with Zn_xFe_3-xO₄, for x= 0,0.2,0.4,0.6,0.8 and sintering temperature at 1000 °C, 1100 °C,1200 °C for six hours. The phase compositions of the synthesized Zinc Ferrite (ZF) were verified using X-ray Diffraction (XRD), hardness testing using hardness Vickers, density and thermal conductivity for composite was studied. The result shows the sample with ratio 0.8 and 1200 ^oC sintering temperature gives the highest value of thermal conductivity with 9.7614 W/m²K and the lowest thermal resistance with 0.1024 m²K / W.

Abstract: SiO₂ compound was introduced into zinc ferrite using formula (1-x)ZnFe₂O₄ – xSiO₂ synthesized by sol-gel method where distilled water and citric acid was used as a solvent and binder agent. The produced samples were annealed at 450 °C for 1h. The AFM result analysis show that the average surface roughness and particle size decreased as the compositions of x was increased. XRD results analysis confirmed the formation of spinel structures with crystallite size within range 11.27 – 4.72 nm. UV-Vis analysis to determine the energy band gap of the (1-x)ZnFe₂O₄ – xSiO₂ samples. It shows that the energy band gap increased as the composition of SiO₂ was increased due to the dielectric properties of silicon dioxide. FTIR results analysis exhibit common band in the range of 400 – 4000 cm^-1. The observed band near 2350 cm^-1 shows the presence of oxygen-oxygen bond in the face centered cubic (fcc) crystal lattice of oxygen atoms. The addition of SiO₂ into ZnFe₂O₄ will help to enhance the morphological structures and optical properties. This new proposed dielectric material can be used as dielectric substrate microstrip patch antenna.

Abstract: This project researched a mechanism of the decomposition of zinc ferrite (ZnFe₂O₄) to be zinc oxide (ZnO) and calcium ferrite (Ca₂Fe₂O₅) by using calcium oxide (CaO) from lime as a reducing agent. Zinc ferrite was mostly found in electric arc furnace dust (EAFD), which is a by product from a steel making industry. The experiment was simple as following. The EAFD was mixed with lime in mole ratio of zinc ferrite and calcium oxide at 1:2, 1:3 and 1:4 and then compressed into pellets. Effects of mole ratio, temperatures and times on the decomposition were studied. The conditions used in these experiments were 800, 900, 1,000 and 1,100 oC for 2, 4 and 6 hours. The results showed that the suitable conditions for the decomposition of zinc ferrite by calcium oxide could be as low as 800 oC for only 2 hours with mole ratio of zinc ferrite from EAFD and calcium oxide from lime as 1:2. A solubility test was provided to processed samples at the conditions as 0.1 M hydrochloric acid (HCl) at 50 oC for 20 minutes. It was found that EAFD from pyrometallurgical treatment could be decomposed to be zinc oxide and the following by hydrometallurgical treatment could recovery high zinc yield from the remaining residue. However, EAFD treated by only hydrometallurgical process obtained lower zinc recovery due to the high stability of zinc ferrite in HCl and most of the solutions.