Zinc Oxide Compounds Research Articles

Synthesis of ZnO nanoparticle from Electric Arc Furnace (EAF) dust prepared by hydrothermal method via hydroxide precipitation

Electric Arc Furnace (EAF) dust is a type of metallurgical solid waste that is produced as a by-product of steel manufacturing and contains important metals such as zinc (Zn). Processing Zn from EAF dust into metal oxides such as zinc oxide (ZnO) is critical for a variety of applications. The hydrothermal technique of extracting Zn from EAF dust uses hydrochloric acid (HCl) as a leaching agent and sodium oxide (NaOH) as a precipitating reagent. In this study, the process begins with leaching using HCl 3 M at a temperature of 80 °C for 5 hours. The product is then filtered to separate the Zn and other components in the EAF dust. The method is then continuing for precipitation using NaOH 10% as a precipitating agent. Then, initiating the hydrothermal process with time variations of 1, 3, and 6 hours and temperatures of 120 °C, 150 °C, and 200 °C. The UV-Vis characterization result showed that the absorbance value was around 365 nm, which is typical of ZnO. The XRF analysis demonstrated an increase in the presence of ZnO compound. The XRD results showed that as the hydrothermal temperature and duration increased, so did the crystallinity in ZnO. The results shown that ZnO nanoparticles can be prepared from EAF dust as a raw material using the hydrothermal technique via hydroxide precipitation.

Plant mediated-green synthesis of zinc oxide nanoparticles: An insight into biomedical applications

Abstract Green synthesis of zinc oxide (ZnO) nanoparticles (NPs) using various plant extracts as reducing and capping agents has gained attention in recent research. The green synthesis of ZnO NPs offers several advantages such as being simple, eco-friendly, safe, cost-effective, and reproducible approach with high stability. Hence, this article provides an overview of zinc metal and ZnO compounds, and traditional chemical and physical synthesis of ZnO NPs with primary focuses on the green synthesis of ZnO NPs. This study discusses various plant extracts used and the proposed mechanisms in the green synthesis of ZnO NPs. Additionally, it explores the cytotoxic mechanisms of the green-synthesized ZnO NPs and addresses the various biomedical applications of ZnO NPs, including antibacterial, anticancer, antidiabetic, antioxidant, antifungal, antiviral, antiparasitic, anti-inflammatory, and wound healing. Moreover, the review critically discusses the toxicity of ZnO NPs and emphasizes the need for more toxicological studies to ensure the safety and facilitate the risk assessments and risk management of ZnO NPs. Furthermore, this review underlines the challenges associated with the translation process of ZnO NPs from bench to market, including the complex and time-consuming regulatory approval process for ZnO NPs, which requires a multidisciplinary approach involving scientists, regulators, and manufacturers.

Comparative antimicrobial activity of four different endodontic sealers.

Dental cements are widely used in the clinical routine, specifically for root canal sealing. Within this context, it is expected that these materials present antimicrobial activity, since it would help in the prevention of apical and periapical infections. The present study aimed to comparatively verify the antimicrobial activity of four dental cements against microorganisms that are routinely isolated from endodontic infections. Reference strains of Enterococcus faecalis, Candida albicans and Escherichia coli were submitted to the agar diffusion test and to modified direct contact test using four different sealers: an eugenol zinc oxide compound, an epoxy resin associated to calcium hydroxide and bismuth, a mineral trioxide aggregate (MTA) and a bioceramics. Different E. coli, C. albicans and E. faecalis growth inhibition profiles were observed in the agar diffusion assay. In the direct contact test, the bioceramics presented a higher microbicide activity on all microorganisms tested herein. Dental cements have different antimicrobial activities, being that the bioceramics present the most consistent antimicrobial activity, and that the direct contact test presented more uniform results than the agar diffusion test. Thisstudyrevealstheantimicrobial activitiesof different cements and allow dentiststodecidewhichmaterialtoemployintheirdailypractice.

Highly Sensitive and Real-Time Detection of Zinc Oxide Nanoparticles Using Quartz Crystal Microbalance via DNA Induced Conjugation.

With the development of nanotechnology, nanomaterials have been widely used in the development of commercial products. In particular, zinc oxide nanoparticles (ZnONPs) have been of great interest due to their extraordinary properties, such as semiconductive, piezoelectric, and absorbance properties in UVA and UVB (280–400 nm) spectra. However, recent studies have investigated the toxicity of these ZnONPs; therefore, a ZnONP screening tool is required for human health and environmental problems. In this study, we propose a detection method for ZnONPs using quartz crystal microbalance (QCM) and DNA. The detection method was based on the resonance frequency shift of the QCM. In detail, two different complementary DNA strands were used to conjugate ZnONPs, which were subjected to mass amplification. One of these DNA strands was designed to hybridize to a probe DNA immobilized on the QCM electrode. By introducing the ZnONP conjugation, we were able to detect ZnONPs with a detection limit of 100 ng/mL in both distilled water and a real sample of drinking water, which is 3 orders less than the reported critical harmful concentration of ZnONPs. A phosphate terminal group, which selectively interacts with a zinc oxide compound, was also attached at one end of a DNA linker and was attributed to the selective detection of ZnONPs. As a result, better selective detection of ZnONPs was achieved compared to gold and silicon nanoparticles. This work demonstrated the potential of our proposed method as a ZnONP screening tool in real environmental water systems.

Structure design, preparation and performance of a novel composite coating on medical magnesium-zinc alloy

Magnesium alloy is a promising implant material, but its inherent defects limit its clinical application. In this article, the CaP pre-coating and polycaprolactone (PCL) composite coatings doped with different hydroxyapatite (HA) and zinc oxide (ZnO) nanoparticles were successively prepared on the surface of Mg6Zn alloy using hydrothermal method and dip coating technique.Results show that ZnO compounds was formed in the CaP pre-coating on the solution treated Mg6Zn alloy, which can enhance the bonding strength of CaP compounds with alloy substrate. Comparing with the PCL coating on bare alloy, the bond strength of the PCL coating on CaP pre-coating was increased by about 5 times. Therefore, the preparation of CaP pre-coating is necessary because it can help to improve the bonding strength of the PCL coating on the substrate, and effectively avoid the peeling, blistering and loss of the barrier effect of the PCL coating. The nanoparticles in the composite coating play important roles for fabricating multifunctional coating. Firstly, doping HA and ZnO nanoparticles help to increase surface roughness of the composite coating, which is beneficial to cell attachment and proliferation. Secondly, the formation of porous structure in the composite coating enable it the ability to control the degradation rate of the matrix by adjusting the porosity. Thirdly, the composite coating doped with ZnO nanoparticles brings better antibacterial properties for magnesium alloy implants. The alloy coated with CaP pre-coating and (2wt.%nHA + 2wt.%nZnO)/PCL composite coating has antibacterial rate of over 90 % and cell proliferation rate of about 90 %, demonstrating it can be used as a potential multifunctional medical implant material.

Structural and morphological studies of ZnO nanostructures

Zinc oxide (ZnO) nanostructures were manufactured successfully using the sol-gel approach in this study. The impact of calcination temperatures on their structural and morphological properties is studied using three different calcination temperatures (350, 400, and 450 °C). XRD, FE-SEM, EDS, and a Raman scattering spectroscope were used to characterize the samples. In all samples, X-ray diffraction (XRD) of calcined samples (350-450 °C) reveals the presence of the wurtzite hexagonal nanocrystalline structure of ZnO compound. The XRD patterns showed no additional peaks, indicating that the final product is exclusively ZnO nanostructures. The FE-SEM pictures of a calcined ZnO sample at 450°C revealed a porous structure, longer length and diameter, and agglomeration of mixed polyhedral shape particles as the calcination temperature increased. The presence of necessary oxide material in the EDS spectrum confirmed the synthesis of ZnO, indicating that the purity of ZnO was appropriate. Finally, using Raman spectroscopy, the vibrational characteristics of ZnO were studied. Several bands in Raman spectra appeared to belong to ZnO vibrational modes, confirming the purity of the produced ZnO samples. The findings of such a study were presented in this paper.

Hygroscopicity Enhancement of Low Temperature Hydrothermally Synthesized Zinc Oxide Nanostructure with Heterocyclic Organic Compound for Humidity Sensitization

Materials that have hygroscopic capabilities are potent sensing elements for humidity sensors. The hygroscopic behaviour of zinc oxide (ZnO) with modified nanostructure was synthesized and characterized. Heterocyclic additive was added on ZnO to improve its hygroscopic capability for humidity sensitization. ZnO capability of water molecule adsorption was tested with a hygroscopic characterization method adapted from American Society for Testing and Materials (ASTM) method for hygroscopic determination. It was found that inclusion of additive improves the water retention and release ZnO, making it more viable for use in sensors that take advantage of mechanical strain due to weight for humidity determination. The hygroscopic behaviour was observed in the steeper gradient on the mass change during humidity exposure to the ZnO compound with the additive compared to non-additive ZnO. Furthermore, the additive loaded ZnO showed greater reliable regression, R2 value (3.56 %) compared to the non-additive ZnO sample. Crystal analysis via X-ray diffraction (XRD) revealed increment on ZnO characteristic peaks (002) and (101) upon addition of the organic compound to the ZnO which influence the nanostructure of the material. Field emission scanning electron microscopy (FESEM) indicates porous and hemispherical nanostructure. Elemental analysis showed minimal impurities present on both ZnO and additive loaded ZnO. The hygroscopic capabilities of ZnO synthesized with low temperature hydrothermal technique allows for implementation in many humidity sensing options required by industries of various fields.

A new route of cross‐linking of carboxylated acrylonitrile‐butadiene rubber via zinc oxide‐amino acid network formation

AbstractHerein, we present a strategy that leads to the formation of a high‐performance elastomeric material based on the carboxylated acrylonitrile‐butadiene rubber (XNBR). A unique cross‐linking route for XNBR has been designed, which does not involve typical cross‐linking agents such as sulfur. In this study, the show cause‐effect of zwitterionic compounds as the secondary cross‐linking agent for ionic elastomer has been investigated. Naturally occurring lysine (Ly) and tryptophan (Trp) amino acid are the zwitterionic compounds, which have been explored here. This approach results in the formation of a cross‐linked ionic elastomer that houses a dual ionic network structure formed by zinc oxide (ZnO) and amino acid. XNBR cross‐linked by ZnO and different amino acid compounds exhibit superior physical properties as compared to the conventional cross‐linking system. Fourier transform infrared spectroscopy, transmission electron microscope, and swelling study analyzes confirm the existence of zinc‐carboxylate and zwitterionic network in XNBR after the cross‐linking process. The dynamic mechanical analysis, differential scanning calorimetry, and oscillating disk rheometer analyzes show various thermal relaxations and transitions present in the dual cross‐linked XNBR. The ZnO and amino acid cross‐linked XNBR rubber with 2.5 phr of Ly and 5 phr of Trp show the highest tensile strength of 42.4 and 39.7 MPa, respectively, which is mostly higher than the previously reported values for ionic cross‐linked elastomers.

Effects of Temperature on Intra-Band Photoluminescence of Zinc Oxide (ZnO) Semiconductor

In this paper, the Photoluminescence intensity of Zinc oxide compound semiconductor in conduction band to valence band, ICV , conduction band to localized trap centre, ICT and localized trap centre to valence band, IT V radiative recombination mechanisms are discussed in different temperatures. By varying temperature, the dominated radiative recombination mechanisms are studied from the three radiative recombination mechanisms. At high values of temperature, the intensity of light in band-to-band radiative recombination mechanism dominates for all values of energies. For high values of impurity trap density, only the intensity of light in conduction band to trap level radiative recombination mechanisms dominates for all energies.

Heat transport behavior of bicrystal ZnO containing tilt grain boundary

Zinc oxide (ZnO), as a conventional semiconductor material, has excellent characteristics, such as piezoelectricity, photoelectricity, gas sensitivity, etc. With the improvement of nanopreparation technology, different types of nanostructrued ZnO compounds have appeared and their heat conductions have become a main research topic in nanodevices. In order to study the effects of grain boundary on the thermal properties of materials of this kind, bicrystal ZnO containing small-angle and high-angle grain boundaries are constructed by the embedded dislocation line and coincidence site lattice method. The variation of grain boundary energy with tilt angle is studied by the non-equilibrium molecular dynamics simulation. In addition, the dislocation density is calculated by using the Frank-Bilby formula. Our results show that the grain boundary energy and dislocation density increase with the increase of tilt angle in a small-angle region, and they tend to be stable in a high-angle region. The tilt angle of 36.86° is defined as the transition angle. The trend of the Kapitza resistance is the same as that of the grain boundary energy and satisfies the theoretical value from the extended Read-Shockley model. Furthermore, it is found that both the Kapitza resistance and thermal conductivity have a significant size effect. When the sample length is between 23.2 nm and 92.6 nm, the Kapitza resistance decreases sharply with the increase of the length and then tends to be stable. The thermal conductivity of the sample increases with length increasing, but is always less than that of the single crystal. At the same time, temperature is an important factor affecting the heat transport properties. The Kapitza resistance and thermal conductivity decrease with temperature increasing. At different temperatures, the Kapitza resistance of 38.94° grain boundary sample is greater than that of 5.45° grain boundary sample. In order to further explore the influence mechanism of grain boundary angle on heat conduction, the phonon state density of 5.45° and 38.94° grain boundary sample are calculated. The results indicate that the high-angle grain boundary has stronger scattering for acoustic branch phonons and the peak frequency becomes lower, whereas the optical branch ones have almost no effect on the heat conduction.

Pengaruh Fortifikasi Zat Besi Menggunakan Fe-Sulfat, Fe-Fumarat dan Na Fe EDTA Terhadap Kualitas Sensori Produk-Produk Olahan Tepung Terigu

The consumption of wheat flour in Indonesia is very high reaching 5.9 million tons during year 2016 and tends to increase steadily every year. The National Standardization Agency of Indonesia (BSN) of Wheat Flour (2009) requires the fortification with minimum iron of 50 ppm (as Fe-elemental). Study conducted byIndonesian ministry of health based on WHO recommendation (2006) states that for wheat consumption 75-149 g/day, fortificication wheat flour with iron should be as much as 60 ppm (in the form of Fe-fumarate or Fe-sulphate) or 40 ppm (in the form of NaFeEDTA compound), zinc 55 ppm (in the form of zinc oxide compound), and folic acid 2.6 ppm. The aim of this research was to evaluate the effect of fe fortification using 3 types of fe fortifcants: Ferous fumarat, Ferous sulfat and NaFeEDTA), zinc (in form of Zn oksida), vitamin B1, vitamin B2, asam folat (as premix) on sensory quality of wheat flour products such as bread, pao, cookies, noodle and macaroni. The result showed that Fe fortification using Fe-sulfat, Fe-fumarat dan Na Fe-EDTA in wheat flour did not significantly affect sensory properties of breads and pao. For cookies, NaFeEDTA slightly affect on texture (slightly harder). For noodle and macaroni, NaFeEDTA dan ferous-sulfat affect on color of productss to become darker. Overall, fe-fumarat was recommended fortificant for iron fortification of wheat flour with the lowest effect on sensory properties of wheat products.

Effects of Transition Energy on Intra-Band Photoluminescence of Zinc Oxide (ZnO) Semiconductor under Low injection Level

This paper presents the effects of the transition energies on photoluminescence intensities in Zinc Oxide compound semiconductor due to the intra-band transition of free carriers. The excitation of free carriers from the valence band to conduction band and from different localized state to the conduction band by the illumination of sufficient energy is considered. A theoretical model for minority carrier trapping is also investigated to explain the dependence of the photoluminescence on the trap energy. Variation of photoluminescence intensities along with localized state energy and transition energy is considered at different temperatures. As temperature increases the photoluminescence due to the transition of free electrons from the conduction band to the valence band, from the conduction band to the localized states and from the localized states to the valence band are increasing.

Oxide zinc addition in cement paste aiming electric arc furnace dust (EAFD) recycling

Large amounts of electric arc furnace dust (EAFD) are generated in steel production, highlighting the need for recycling alternatives like the use of EAFD in production of building materials. However, EAFD delays hydration reactions of concrete. This study presents a model of cement hydration using ZnO as admixture and analyzes phenomena associated with zinc oxide compounds in cement pastes. Cement samples were analyzed by X-ray diffraction (XRD) with Rietveld refined, scanning electron microscopy (SEM), and characteristic X-ray mapping 1, 2, 4, 7, and 14days into setting. Zn was present as ZnO on day 1. A new phase formed containing CaZn2(OH)6·2H2O on day 4, suggesting the transition of ZnO to Zn hydroxide, especially on day 7, when hydration reactions were visually detected and Zn was found only as hydroxide. CaZn2(OH)6·2H2O enables the hydration of cement with ZnO. A model to explain hydration reactions of cement admixed with ZnO was proposed.

Production of Chitosan/Zinc Oxide Complex by Ultrasonic Treatment with Antibacterial Activity

This study was conducted with the objective of investigating the physical and antimicrobial properties of structured zinc oxide compounds in chitosan submitted to different times of ultrasonic treatment. Zinc oxide particles were dispersed in water and coated with medium molar mass chitosan and two other sonicated samples, following a simple methodology. Before drying, the chitosan/zinc oxide water suspensions were characterized by rheological tests. Their rheological behavior depended on the period of time during which the chitosan sample was submitted to ultrasound. After drying, the microparticles were characterized by infrared spectroscopy, atomic absorption spectrophotometry and scanning electron microscopy (SEM). The microparticles were investigated as for their particle size distribution (PSD). SEM and PSD results revealed that the chitosan/zinc oxide microparticles had a multimodal dispersion. The antibacterial activity of the neat zinc oxide nanoparticles and of the microparticles was evaluated against Escherichia coli and Staphylococcus aureus. The results showed that the ZnO nanoparticles had a lower minimum bactericidal concentration (500 μm/mL against E. coli and 650 μm/mL against S. aureus) than the chitosan-coated/ZnO microparticles. The microparticles with the lowest average particle size and the highest homogeneity exhibited the highest antibacterial activity against both bacteria. This result was attributed to the additional antibacterial activity of soluble zinc ions and of the chitosan sample.

Novel Ammonium Acetate Fuel Based Autocombustion Method for the Preparation of Nickel Doped Zinc Oxide Nanoparticles

A novel approach for the synthesis of nickel doped zinc oxide dilute magnetic semiconductors has been discussed in this paper. The use of fuels such as ammonium acetate and urea were used in this paper in order to produce zinc oxide nanoparticles of very small size ranges with nickel content varying from 2 to 10 percent. The produced particles were observed to be single phase materials which were confirmed by evident ferromagnetic properties of these particles in the absence of individual nickel or nickel oxide phases. The synthesized particles were also tested for their optical emission properties which yielded in the emission peaks related to the nickel doped zinc oxide compound instead of individual phases confirming the earlier processed information.

Na to tailor the band gap and morphology of ZnO nanograins

Sodium doped and undoped zinc oxide compounds are synthesized using sol–gel auto combustion method. The doping has five different concentrations of sodium in zinc oxide. They are characterized for phase and crystal structure using X-ray diffractrometer. It is confirmed that the doping of the impurity atoms show lattice changes. The average particle size of samples are found to be in the range between 32 and 62 nm. Williamson–Hall plots show strain induced in crystallites. Scanning electron microscope micrographs show the morphology of the Na doped samples as nano pebbles, nano platelets and nano rods having considerable width and length; while small thickness. Fourier transform infra-red spectrophotometer and FT Raman studies show the persistent peaks corresponding to characteristic Zn–O bonds. Ultraviolet–visible–near infra-red spectrophotometer studies reveal the decrease in absorbance and red shift in band gap with increasing Na content. The fluorescence spectral analysis of the samples demystifies the existence of oxygen deficient sites. The varying of oxygen vacancy helps band gap tailoring while enhancing Na doping in ZnO.

Iron removal from zinc liquors originating from hydrometallurgical processing of spent Zn/MnO2 batteries

In this work, the removal of iron from leach liquors obtained after processing of spent alkaline and zinc-carbon Zn/MnO2 batteries with initial iron ion concentration in the range of 270 to 580mg/L has been studied. Solid Na2CO3, ZnO and fine ground waste electrode materials separated from processed Zn/MnO2 batteries were tested as precipitation agents. All used precipitation agents make it possible to remove more than 99% Fe, but electrode materials have been found to be more efficient precipitants at lower pH values. The different course of iron precipitation is probably caused by different solubility of iron compounds formed during the precipitation with various precipitation agents. Precipitates in which iron was present as FeO(OH) originated from processing the leach liquors with Na2CO3 or ZnO Precipitates from processing the leach liquors with electrode materials contained zinc-iron non-stoichiometric oxides, which was established as results of experiments performed with a synthetic solution containing 1.54g/L Fe.The benefits of potential use of waste materials containing zinc oxide compounds in applications to remove iron from zinc sulphate liquors would include high efficiency, low cost and good filterability of the formed precipitates.

Transmission properties of a new glass ceramic and doped with Co2+ as saturable absorber for 1.54 µm Er glass short pulse laser

The preparation and characteristics of a new transparent glass ceramic were described. Crystal phase particles with nanometer size were successfully precipitated in glass matrix, which was confirmed to be one of indium aluminum zinc oxide compounds (InxAlyZnzO). The presence of aluminum (Al) and indium (In) impurities in the zinc oxides (ZnO) crystal lattice leads to some changes of the carrier concentration in the material and then promote the sharply changes of transmission spectra in IR range wavelength. And subsequently, the IR cut-off edge blue shifted from 5.5 μm in base glass to 3 μm in transparent glass ceramic sample. Furthermore, passive Q switched 1.54 μm Er glass laser pulses with pulse energy of 10 mJ and pulse width of 800 ns were successfully obtained by using the cobalt doped transparent glass ceramic as a saturable absorber.

Comparative effects of indium/ytterbium doping on, mechanical and gas-sensitivity-related morphological, properties of sprayed ZnO compounds

In this study, conducting and transparent indium-doped zinc oxide (ZnO) thin films have been deposited on glass substrates by the micro-spray technique. First, zinc oxide layers were obtained by spaying a solution of propanol and zinc acetate in acidified medium. Alternatively, some of the obtained films were doped with indium (In) at the molar rates of: 1%, 2% and 3%. In addition to the classical structural investigated using XRD, AFM and SEM techniques, microhardness Vickers (Hv) measurements have been carried out along with comparative morphological prospecting. The specific gases sensitivity-related surface morphology of the doped ZnO compounds was favorably different from that of the non-doped ones, and showed a thin overlay structure. Results were compared to those recorded for similar ytterbium-doped material.

Thermoelectric Properties of Amorphous Zinc Oxide Thin Films Fabricated by Pulsed Laser Deposition

Thermoelectric properties of non-doped amorphous zinc oxide (ZnO) thin film were studied at between room temperature and around 673 K, where the samples were prepared by pulsed laser deposition at room temperature. The results of X-ray diffraction, transmittance spectroscopy and electron microscope observation indicate that both as-deposited film and heat treated film had amorphous structure with random hexagonal network of ZnO, where the latter included crystallized ZnO grains. The highest absolute value of Seebeck coefficient a was 135 μV/K at 643 K, where the electrical resistivity p was 1.01 x 10 - 4 Ωm and the power factor P was 1.79 x 10 - 4 W/mK 2 , and the a was almost the same as those of other ZnO compounds such as (ZnO) 5 In 2 O 3 and (Zn 1 - x Al x )O. The heat treatment dependence of the p and the a indicated the decrease of free electrons originated in amorphous and the transition to the quasi-stable phase of amorphous. It was suggested that the amorphous structure with variable range hopping conduction relates to the thermoelectric properties of a-ZnO thin film.