scholarly journals Microwave-assisted synthesis and characterization of microstar shaped zinc oxide

Quimica Hoy ◽  
2012 ◽  
Vol 2 (3) ◽  
pp. 3
Author(s):  
Idalia Gómez ◽  
Miguel José Yucam´án ◽  
Flor Palomar
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Microwave Assisted Synthesis ◽  
Stoichiometric Ratio ◽  
Crystalline Materials ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
Synthesis Procedure ◽  
Post Synthesis

A microwave-assisted solution-phase approach has been applied for the synthesis ofzinc oxide microstructures. Toe synthesis procedure was carried out by using the reagents: Zinc ni trate and Methenamine, at stoichiometric ratio. Analysis by means ofX-ray Diffraction (XRD) shows a crystalline phase in hexagonal wurtzite arrangement for ZnO. The presence ofmicrostar shaped zinc oxide (2-3μm) with nanorods,f50nm) arranged has been confirmed from High Resolution Scanning Electron Microscopy (HRSEM). The formation of nanorods was confirmed by Transmission Electron Microscopy. In Raman spectroscopy a red shift was detected in the microstructures compared with ZnO bulk. High crystalline materials without additional post-synthesis treatrnent were found.

scholarly journals Zinc Oxide and Silver Nanoparticle Effects on Intestinal Bacteria

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2489
Author(s):  
Ami Yoo ◽  
Mengshi Lin ◽  
Azlin Mustapha
Keyword(s):  
Electron Microscopy ◽  
Zinc Oxide ◽  
Morphological Changes ◽  
Intestinal Bacteria ◽  
Bacterial Cells ◽  
Ag Nps ◽  
Zno Nps ◽  
Bifidobacterium Animalis ◽  
Transmission Electron

The application of nanoparticles (NPs) for food safety is increasingly being explored. Zinc oxide (ZnO) and silver (Ag) NPs are inorganic chemicals with antimicrobial and bioactive characteristics and have been widely used in the food industry. However, not much is known about the behavior of these NPs upon ingestion and whether they inhibit natural gut microflora. The objective of this study was to investigate the effects of ZnO and Ag NPs on the intestinal bacteria, namely Escherichia coli, Lactobacillus acidophilus, and Bifidobacterium animalis. Cells were inoculated into tryptic soy broth or Lactobacilli MRS broth containing 1% of NP-free solution, 0, 12, 16, 20 mM of ZnO NPs or 0, 1.8, 2.7, 4.6 mM Ag NPs, and incubated at 37 °C for 24 h. The presence and characterization of the NPs on bacterial cells were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Membrane leakage and cell viability were assessed using a UV-visible spectrophotometer and confocal electron microscope, respectively. Numbers of treated cells were within 1 log CFU/mL less than those of the controls for up to 12 h of incubation. Cellular morphological changes were observed, but many cells remained in normal shapes. Only a small amount of internal cellular contents was leaked due to the NP treatments, and more live than dead cells were observed after exposure to the NPs. Based on these results, we conclude that ZnO and Ag NPs have mild inhibitory effects on intestinal bacteria.

Detonation Synthesis of Nano-Size Materials

1995 ◽  
Vol 418 ◽  
Author(s):  
J. Forbes ◽  
J. Davis ◽  
C. Wong
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Detonation Synthesis ◽  
X Ray Diffraction ◽  
Crystalline Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Nano Size

AbstractThe detonation of explosives typically creates 100's of kbar pressures and 1000's K temperatures. These pressures and temperatures last for only a fraction of a microsecond as the products expand. Nucleation and growth of crystalline materials can occur under these conditions. Recovery of these materials is difficult but can occur in some circumstances. This paper describes the detonation synthesis facility, recovery of nano-size diamond, and plans to synthesize other nano-size materials by modifying the chemical composition of explosive compounds. The characterization of nano-size diamonds by transmission electron microscopy and electron diffraction, X-ray diffraction and Raman spectroscopy will also be reported.

Growth and Characterization of Misostructural Zinc Oxide Tubes

2005 ◽  
Vol 23 ◽  
pp. 293-296
Author(s):  
X.W. Sun ◽  
C.X. Xu ◽  
B.J. Chen ◽  
Y. Yang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Zinc Oxide ◽  
Growth Process ◽  
Hexagonal Structure ◽  
Metallic Zinc ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Zinc oxide (ZnO) microtube has been fabricated by heating the mixture of ZnO and graphite powders in the atmosphere. The ZnO microtubes showed perfect hexagonal profiles with bell-mouth or normal hexagonal tops. Both X-ray diffraction (XRD) and high-resolution transmission electron microscopy (TEM) demonstrated that the product was composed of ZnO with typical hexagonal structure grown predominantly along (002) direction. The growth process was interpreted by means of vaporliquid-solid mechanism combining with the evaporation of metallic zinc.

Microwave-Assisted Synthesis and Characterization of Zinc Oxide Micropowder

2010 ◽  
Vol 93-94 ◽  
pp. 643-646
Author(s):  
Pusit Pookmanee ◽  
Supasima Makarunkamol ◽  
Sakchai Satienperakul ◽  
Jiraporn Kittikul ◽  
Sukon Phanichphant
Keyword(s):  
Zinc Oxide ◽  
Radiation Power ◽  
Ammonium Hydroxide ◽  
Zinc Nitrate ◽  
Hexagonal Structure ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted

Zinc oxide micropowder was synthesized by a microwave-assisted method. Zinc nitrate and ammonium hydroxide were used as the starting precursors with the mole ratio of 1:1. The white precipitated powder was formed after adding ammonium hydroxide until the pH of final solution was 9 and treated with the microwave radiation power at 1000 Watt for 2-6 min. The phase of zinc oxide micropowder was examined by X-ray diffraction (XRD). A single phase of hexagonal structure was obtained. The morphology and chemical composition of zinc oxide micropowder were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The particle was plate-like in shape with the range of particle size of 0.1-0.5 µm. The elemental composition of zinc oxide showed the characteristic X-ray energy value as follows: zinc of Lα = 1.012 keV, Kα = 8.630 keV and Kβ = 9.570 keV and oxygen of Kα = 0.525 keV, respectively.

scholarly journals A Microwave-Assisted Synthesis of Zinc Oxide Nanocrystals Finely Tuned for Biological Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 212 ◽  
Author(s):  
Nadia Garino ◽  
Tania Limongi ◽  
Bianca Dumontel ◽  
Marta Canta ◽  
Luisa Racca ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Colloidal Stability ◽  
Cell Uptake ◽  
Biological Behavior ◽  
Microwave Assisted Synthesis ◽  
Biological Applications ◽  
Uniform Size ◽  
Chemical Surface ◽  
Microwave Assisted ◽  
Synthesis Procedure

Herein we report a novel, easy, fast and reliable microwave-assisted synthesis procedure for the preparation of colloidal zinc oxide nanocrystals (ZnO NCs) optimized for biological applications. ZnO NCs are also prepared by a conventional solvo-thermal approach and the properties of the two families of NCs are compared and discussed. All of the NCs are fully characterized in terms of morphological analysis, crystalline structure, chemical composition and optical properties, both as pristine nanomaterials or after amino-propyl group functionalization. Compared to the conventional approach, the novel microwave-derived ZnO NCs demonstrate outstanding colloidal stability in ethanol and water with long shelf-life. Furthermore, together with their more uniform size, shape and chemical surface properties, this long-term colloidal stability also contributes to the highly reproducible data in terms of biocompatibility. Actually, a significantly different biological behavior of the microwave-synthesized ZnO NCs is reported with respect to NCs prepared by the conventional synthesis procedure. In particular, consistent cytotoxicity and highly reproducible cell uptake toward KB cancer cells are measured with the use of microwave-synthesized ZnO NCs, in contrast to the non-reproducible and scattered data obtained with the conventionally-synthesized ones. Thus, we demonstrate how the synthetic route and, as a consequence, the control over all the nanomaterial properties are prominent points to be considered when dealing with the biological world for the achievement of reproducible and reliable results, and how the use of commercially-available and under-characterized nanomaterials should be discouraged in this view.

Structural Characterization of Microwave-Assisted Solution-Synthesized Strontium-Substituted Hydroxyapatite

NANO ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. 1650115
Author(s):  
Jianguo Liao ◽  
Yanqun Li ◽  
Xiali Guan ◽  
Jingxian Liu ◽  
Yongxiang Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Hexagonal Structure ◽  
Hydroxyapatite Nanoparticles ◽  
Solution Synthesis ◽  
X Ray ◽  
Molar Ratios ◽  
Microwave Assisted ◽  
Transmission Electron

Hydroxyapatite and strontium-substituted hydroxyapatite nanoparticles (n-HA and Sr-HA) were prepared by microwave-assisted solution synthesis with aqueous solutions of various Sr/(Sr[Formula: see text]Ca) molar ratios ranging from 0% to 15%. The structural properties of the hydroxyapatite powders were investigated by X-ray powder diffraction, Fourier transform infrared spectroscopy and Raman spectra, field emission scanning electron microscopy coupled with energy dispersive X-ray spectrometry and transmission electron microscopy. The results confirmed that strontium ions had been incorporated into the hydroxyapatite lattice. The synthetic n-HA and Sr-HA nanocrystalline consisted of hydroxyapatite crystalline phase with hexagonal structure, and the particle size was 30–40 × 60–70[Formula: see text]nm and 40–50 × 70–80[Formula: see text]nm, respectively. The calcined HA particle size ranged from about 120[Formula: see text]nm to 150[Formula: see text]nm, the calcined Sr-HA products were composed of spherical aggregates with a size of about 70–100[Formula: see text]nm. The incorporation of Sr ions lead to the formation of vacancies in the crystal structure of the HA. The results indicated that the strontium substitution did not change the crystal structures. More Sr resulted in less calcined crystallites and formed agglomerates owing to the size effect.

scholarly journals MICROWAVE–ASSISTED SYNTHESIS OF MOLYBDENUM DISULFIDE (MoS2)

2018 ◽  
Vol 55 (1B) ◽  
pp. 57
Author(s):  
Nguyen Thi Minh Nguyet
Keyword(s):  
Electron Microscopy ◽  
Microwave Irradiation ◽  
Molybdenum Disulfide ◽  
Low Cost ◽  
Lithium Ion ◽  
Microwave Assisted Synthesis ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
Transmission Electron ◽  
Synthesis Procedure

Molybdenum disulfide (MoS2) nanostructured has been synthesized by a facile and rapid microwave, in which ethylene glycol can act as an excellent susceptor of microwave irradiation. The structure and morphology of MoS2 were characterized by X–ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that nanometer scaled (< 100 nm) molybdenum disulfide with different morphologies can be successfully fabricated by microwave liquid–state method. Microwave irradiation can make localized heating that allows higher heating rates and shorter processing time. The low–cost synthesis procedure paves the way for the exploitation of the present product as electrode material in lithium ion batteries (LIBs). 

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