Magnesium Oxide Nanopowder Research Articles

Chitosan/MgO NPs/CQDs bionanocomposite coating: Fabrication, characterization and determination of antimicrobial efficacy

The development of new polymer nanocomposites or antibacterial coatings is crucial in combating drug-resistant infections, particularly bacterial infections. In this study, a new chitosan polymer based nanocomposite reinforced with magnesium oxide nanopowders and carbon quantum dots was fabricated by sol-gel technique and coated on 316 L stainless steel. In order to gaining the optimal amount of components to achieve the maximum antibacterial properties, the effect of concentration of nanocomposite components on its antibacterial properties was investigated. Crystal structure, microstructure, elemental dispersion, size distribution, chemical composition and morphology of nanocomposite and coating were characterized with various analyses. The obtained results exhibited that the carbon quantum dot and magnesium oxide nanopowders were distributed uniformly and without agglomeration in the chitosan matrix and created a uniform coating. The antibacterial properties of the synthesized samples against Staphylococcus aureus bacteria (gram positive) were evaluated using disk diffusion and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) antibacterial tests. The inhibition growth zone formed around the antibiotic and nanocomposite 25 mg/ml under dark and light was about 32 and 14, 11 mm, respectively. Also, MIC and MBC values for final nanocomposite were 62.5 and 125 μg/ml, respectively.

Comparative Study of MgO Nanopowders Prepared by Different Chemical Methods.

Magnesium oxide (MgO) was synthesized by three different methods: the sol-gel (SG), microwave-assisted sol-gel (MW), and hydrothermal (HT) methods for comparing the influence of the preparation conditions on the properties of the products. The powders were annealed at 450 °C. The samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM/HRTEM), selected area electron diffraction (SAED), energy-dispersive X-ray spectroscopy (EDX), BET specific surface area and porosity, photoluminescence, and UV-Vis spectroscopy. The samples consisted mainly of periclase as a crystalline phase, and the MW and HT preparation methods generated particles with higher specific surface areas. The powders had less-defined morphologies and high levels of aggregation. The optical band gaps of the samples were determined from UV DRS, and the photocatalytic activities of the magnesium oxides obtained by the three methods towards the degradation of methyl orange (MO) under UV light irradiation was evaluated.

Assessing the Dispersion Stability of Antimicrobial Fillers in Photosensitive Resin for Vat Polymerization 3D Printing.

Polymers are widely used in healthcare due to their biocompatibility and mechanical properties; however, the use of polymers in medical products can promote biofilm formation, which can be a source of hospital-acquired infections. Due to this, there is a rising demand for inherently antimicrobial polymers for devices in contact with patients. 3D printing as a manufacturing technology has increased exponentially in recent years. Surgical guides, orthotics, and prosthetics, among other medical devices, created by vat polymerization have been used in hospitals to treat patients. Biocompatible resins are available for these applications, but there is a lack of antimicrobial resins, which would further improve the technology for clinical use. The focus of this study was to assess settling of candidate antimicrobial metal and metal oxide fillers in vat polymerization resin to determine which fillers were compatible with the resin. Dispersion stability was assessed by measuring settling over the maximum print duration of the medium priced desktop 3D printers to evaluate printability of 17 potentially antimicrobial resins. Eight materials displayed settling behavior during the test period: molybdenum oxide, zirconium oxide nanopowder, scandium oxide, zirconium oxide, titanium oxide, tungsten oxide, lanthanum oxide, and magnesium oxide. No settling was observed for manganese oxide, magnesium oxide nanopowder, titanium oxide nanopowder, copper oxide, silver oxide, zinc oxide nanopowder, zinc oxide, silver nanopowder, and gold nanopowder during the test period. This method could be applied to assess settling of other fillers introduced into 3D printing resins before actual printing.

Enhanced dielectric properties of Be-doped magnesium oxide nanopowder

Owing to its applicability in refractory ceramic synthesis, nanoelectronics, optoelectronic and sensing devices, and superconducting products, magnesium oxide (MgO) is recognized to be an important ceramic material. However, it has a relatively low dielectric constant compared to other metal oxide semiconductors, which restricts the range of its bandgap and limits its applicability. Therefore, in this study, we propose and verify a method to improve the dielectric constant of MgO. A sample of MgO powder doped with Be ions was prepared using the Pechini method. The crystal structure of the doped MgO powder was analyzed by x-ray diffraction. Through structural analysis, it was confirmed that a substitution amount of up to 5% of Be ions was possible without breaking the cubic structure. The bonding structure in the lattice of the sample was identified through x-ray photoelectron spectroscopy, and the change in the bonding structure according to the amount of substitution was identified. The dielectric properties of the samples were analyzed as a function of frequency at room temperature. The real and imaginary parts of the dielectric constant were studied at room temperature as a function of frequency and composition. It was confirmed that the dielectric constant increased as the Be ions were substituted. Our results show that improving the low dielectric properties of pure MgO can enable its application to wide bandgap and high voltage applications simultaneously.

Optical, structural and photocatalytic properties of rare earth element Gd3+ doped MgO nanocrystals

In this work, a cost-effective and ecologically friendly way was chosen for the preparation of magnesium oxide (MgO) and gadolinium doped MgO (Gd3+-doped MgO) nanoparticles. The Gd3+ ions caused a shift in the acceptor level, which is proved by the obtained band gap values of the samples which is found to be reduced for Gd3+-doped MgO rather than pure MgO. Three bands related to F + and F oxygen deficiency defects may be seen in the photoluminescence spectra of produced nanomaterials. Crystallinity, particle size, and surface area, of these synthetic photocatalyst were all measured. The photo activity of Gd3+-doped MgO with different weight percent (1, 3, and 5) of Gd3+ has been studied in Methyl Orange (MO) and Methylene Blue (MB) degradation. The photocatalytic behavior of magnesium oxide nanoparticles and rare earth element Gd3+-doped magnesium oxide was studied, and the photocatalytic rate was enhanced by doping of gadolinium under UV radiation was observed. The impact of operational variables like pH and PZC was evaluated. When the efficiency of all produced nanoparticles was compared, it was discovered that the 5 wt% Gd-doped MgO nano powder performed better rather than the rest of the materials.

Polycrystalline infrared-transparent MgO fabricated by spark plasma sintering

Abstract In the present research, polycrystalline magnesium oxide (MgO) bodies were fabricated using spark plasma sintering (SPS) at different temperatures and times from MgO nanopowder. Microstructural development, densification, and optical properties were investigated during SPS. The critical pressure of plastic deformation of the MgO compacts during sintering was also analyzed. The results showed that the plastic deformation phenomenon had a profound effect on the grain size and optical properties. In addition, the optical properties and microstructure of MgO bodies were strongly dependent on sintering temperature and time. Full-dense infrared-transparent magnesium oxide with a relative density of 99.99% was prepared at 1200 °C for 5 min under the pressure of 80 MPa. The spark plasma sintered MgO demonstrated the highest infrared transmittance of 72% in the 3–7 μm wavelength range, which was comparable with the values reported for MgO single crystal.

Prevent Intravenous Therapy (IV) Contamination by Addition of Magnesium Oxide Nanoparticles to Silicone Rubber

Antibacterial material nanocomposites are prepared to manufacture intravenous therapy (IV). These composites prepared by adding Magnesium oxide nano powder (MgO NPs) with a different percent (3, 6, and 9 wt %) to Silicone rubber (SR). The activity of this antibacterial material was inspected against S. aureus and E.coli microorganisms by using Agar Well Diffusion method.
 Results showed that the addition of MgO NPs to SiR causes the following enhancement the antibacterial activity against E.coli and S.aureus by 7.1% and 27.1% respectively, increasing tensile strength by 65.5%, increasing the hardness by11.25%, increasing the wear resistance by 84.5%, increasing surface bearing index (Sbi) by 80.5% , increasing in core fluid retention (Sci) by 8.5%, decreasing surface roughness (Sa) by 65%, decreasing core roughness depth (Sk) by 67% and enhancement the wettability by decreases contact angle to minimum value.

The effects of urea content on the structural, thermal and morphological properties of MgO nanopowders

In the present study, we have looked into the effects of the amount of the combustion fuel of urea on the morphological, thermal and morphological properties of MgO structure. To this goal, three Magnesium Oxide (MgO) samples were synthesized by the combustion method and the as-mentioned properties were characterized by the experimental analysis techniques of X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The functional groups in the samples were also determined using Fourier Transform Infrared (FTIR) spectrometry. The crystallinity percent values for each sample were found to be about in the range of 94–96%. The crystallite sizes of the samples were computed to be in the ranges of 26–37 nm and 23–32 nm for Scherrer and Williamson-Hall methods, respectively. The increasing quantity of urea caused a gradual growth in the lattice parameter of Magnesium Oxide structure. The thermal properties and morphology were affected by the urea content.

Synthesis of magnesium oxide nanopowder via plasma processing route

Synthesis of magnesium oxide nanopowder via plasma processing route

Synthesis of magnesium oxide nanopowder via plasma processing route

We describe a less time consuming and scalable thermal plasma process for the synthesis of magnesium oxide (MgO) nanoparticles. In this process, argon is used as the plasmagen gas to form argon plasma. In the presence of argon plasma magnesite powder was decomposed to form nano magnesia within ten minutes. This as-synthesised magnesia has been analysed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectrum (FT-IR) for phase, morphology and presence of surface functional groups, respectively. The phase and average crystallite size of the as-synthesised powder was determined from XRD pattern. Further, Raman spectroscopy was used to observe the phase and phase purity. Finally, the spherical shape of the as-formed magnesia powder was observed using TEM.

Experimental and Statistical Analysis of MgO Nanofluids for Thermal Enhancement in a Novel Flat Plate Heat Pipes

Metallic fluids like CuO, Al2O3, ZnO, SiO2 and TiO2 nanofluids were widely used for the development of working fluids in flat plate heat pipes except magnesium oxide (MgO). So, we initiate our idea to use MgO nanofluids in flat plate heat pipe as a working fluid material. MgO nanopowders were synthesized by wet chemical method. Solid state characterizations of synthesized nanopowders were carried out by Ultraviolet Spectroscopy (UV), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques. Synthesized nanopowders were prepared as nanofluids by adding water and as well as water/ethylene glycol as a binary mixture. Thermal conductivity measurements of prepared nanofluids were studied using transient hot-wire apparatus. Response surface methodology based on the Box–Behnken design was implemented to investigate the influence of temperature (30–60[Formula: see text]C), particle fraction (1.5–4.5 vol.%), and solution pH (4–12) of nanofluids as the independent variables. A total of 17 experiments were accomplished for the construction of second-order polynomial equations for target output. All the influential factors, their mutual effects and their quadratic terms were statistically validated by analysis of variance (ANOVA). The optimum stability and thermal conductivity of MgO nanofluids with various temperature, volume fraction and solution pH were predicted and compared with experimental results. The results revealed that increase in particle fraction and pH of MgO nanofluids at certain points would increase thermal conductivity and become stable at nominal temperature.

Improved properties of the MEMS-type ion-sorption micropump

In this paper, the authors demonstrate how to improve the properties of a recently elaborated microelectromechanical system (MEMS) ion-sorption micropump in order to generate high and ultrahigh vacuum inside MEMS and miniature nanoelectronics devices. This research goal has been achieved by applying mechanisms leading to an increase of the efficiency of a gas ionization process. One of the cathodes of the micropump was covered with different nanomaterials, which have either good field emission properties (carbon nanotubes) or high secondary emission coefficient (nanoporous silicon and magnesium oxide nanopowder). In this way, the number of primary or secondary electrons which collide with gas particles was multiplied. For all of the modified structures a significant increase of a discharge current inside the micropump was observed. In the case of electrodes covered with MgO, it increased about 1000 times. The use of these cathodes may allow to obtain ultrahigh vacuum inside hermetically sealed MEMS structure.

Synthesis of Magnesium Oxide Nanopowder by Thermal Plasma Using Magnesium Nitrate Hexahydrate

Magnesium oxide (MgO) nanopowder was synthesized by thermal plasma in a novel thermal DC plasma torch using magnesium nitrate hexahydrate. Magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) was obtained from serpentinite (Mg3Si2O5(OH)4; lizardite) (Halilovskiy array, Orenburg region, Russia). The synthesized samples were characterized by analytical techniques including X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD and TEM characterization studies confirmed that MgO nanopowder obtained has periclase structure with high purity, and the particle sizes vary within the range of 100 nm to 150 nm. We believe that the present work will promote further experimental studies on the physical properties and the applications of MgO nanopowders in the fields such as high-densed ceramics, additives in bactericide, and refractory products.

Керамика из нанопорошка оксида магния: создание и свойства

Керамика из нанопорошка оксида магния: создание и свойства

X-ray diffraction analysis of the effect of annealing temperature on the microstructure of magnesium oxide nanopowder

In this study, nanocrystalline MgO powders were prepared using the sol-gel method and annealed in air over a temperature range of [400–700]°C. Various microstructural characteristics were determined using three different X-ray diffraction analysis approaches, i.e., modified Williamson-Hall, modified Warren-Averbach, and variance methods. The transmission electron microscopy micrographs were used to measure the size distributions of the MgO samples. The results obtained using the three different methods were in good agreement. At all temperatures, the main source of dislocation was edge type but as the annealing temperature increased, the crystallite size and dislocation density increased and decreased, respectively, thereby indicating that the crystal quality of the nanopowders was improved.

Investigating the Physical Properties of Sintered Alumina in the Presence of MgO Nanopowder

Magnesium oxide nanopowder is synthesized using magnesium nitrate hexahydrate and oxalic acid as precursors via the sol-gel method. In order to investigate the effect of magnesia nanopowders on the physical properties of sintered alumina, 0.1, 0.3, and 0.5 wt% of MgO are added to alumina. The prepared specimens were sintered at 1570°C for 4 hours under an inert atmosphere. The morphology and size of nanopowders were characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). Structural analysis was investigated by means of Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Outcomes show that by increasing the percentage of MgO, spinel phase (MgAl2O4) has been formed in the structure of alumina. During the sintering process, spinel phase diffused through the grain boundaries and pinned the grain boundaries which led to decrease in grain sizes. So, by decreasing the grain size, the physical properties of sintered alumina have improved.

Synthesis, structural and luminescence studies of magnesium oxide nanopowder

Nanoparticles of magnesium oxide (MgO) have been prepared by low temperature solution combustion and hydrothermal method respectively. Powder X-ray diffraction (PXRD) patterns of MgO samples prepared by both the methods show cubic phase. The Scanning Electron Microscopy (SEM) studies reveal, the combustion derived product show highly porous, foamy and fluffy in nature than hydrothermally derived sample. The optical absorption studies of MgO show surface defects in the range 250–300nm. The absorption peak at ∼290nm might be due to F-centre. Photoluminescence (PL) studies were carried upon exciting at 290nm. The sample prepared via combustion method show broad emission peak centred at ∼395nm in the bluish-violet (3.14eV) region. However, in hydrothermal prepared sample show the emission peaks at 395 and 475nm. These emission peaks were due to surface defects present in the sample since nanoparticles exhibits large surface to volume ratio and quantum confinement effect.

Preparation and antibacterial activity of magnesium oxide nanoplates via sol–gel process

Magnesium oxide (MgO) nanopowders were synthesised by a sol–gel method with different amounts of ammonium hydroxide (NH3·H2O) and characterised by a combination of thermo gravimetric analysis, X-ray diffraction and transmission electron microscopy. It was found that the structure and morphology of MgO nanopowders can be regulated by the addition of NH3·H2O. When an appropriate amount of NH3·H2O was added into the reaction system, plate-like nanoMgO was obtained. The antibacterial activity of MgO nanoplates was also investigated by the minimum inhibition concentration (MIC) test and bactericidal efficacy against Escherichia coli (E. coli, ATCC 25922). The tested results revealed that the MgO nanoplates have great antibacterial effect with an MIC value of 600 mg/l and the bactericidal rate was about 99.8% at a concentration of 500 mg/l. Furthermore, the effect of NH3·H2O on the structure and morphology of MgO nanopowders and on the growth mechanism are briefly discussed. The hydroxide ion of NH3·H2O, in favour of Mg(OH)2 generation in the precursors, is essential for the formation of MgO nanoplates.

Influence of different ions doping on the antibacterial properties of MgO nanopowders

Compared with other inorganic antibacterial agents, magnesium oxide (MgO) nanopowders exhibit a unique antibacterial mechanism and various advantages in applications, having attracted extensive attention. In this study, MgO nanopowders doped with different ions (Li+, Zn2+ and Ti4+) were synthesized by a sol–gel method, respectively. The structures and morphologies of the as-obtained precursors and nanopowders were characterized and confirmed by X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The influence of three metal ions doping on the antibacterial properties of MgO nanopowders was also investigated by their bactericidal activity against Escherichia coli (E. coli, ATCC 25922) using the broth microdilution method and the agar method. The results show that Li-doped MgO exhibits better antibacterial activity, Zn-doped and Ti-doped MgO display poorer antibacterial activity than pure MgO. It can be concluded that the influence of different ions doping on the antibacterial properties of MgO mainly lies on oxygen vacancies and basicity of nanopowders.

Surface properties of calcium and magnesium oxide nanopowders grafted with unsaturated carboxylic acids studied with inverse gas chromatography

Inverse gas chromatography (IGC) was applied at infinite dilution to evaluate the surface properties of calcium and magnesium oxide nanoparticles and the effect of surface grafted unsaturated carboxylic acid on the nanopowder donor–acceptor characteristics. The dispersive components (γsD) of the free energy of the nanopowders were determined by Gray's method, whereas their tendency to undergo specific interactions was estimated based on the electron donor–acceptor approach presented by Papirer. The calcium and magnesium oxide nanoparticles exhibited high surface energies (79mJ/m2 and 74mJ/m2, respectively). Modification of nanopowders with unsaturated carboxylic acids decreased their specific adsorption energy. The lowest value of γsD was determined for nanopowders grafted with undecylenic acid, approximately 55mJ/m2. The specific interactions were characterised by the molar free energy (ΔGASP) and molar enthalpy (ΔHASP) of adsorption as well as the donor and acceptor interaction parameters (KA, KD).