فهرست مطالب

Nano Structures - Volume:7 Issue: 1, Winter 2017

Journal of Nano Structures
Volume:7 Issue: 1, Winter 2017

  • تاریخ انتشار: 1395/12/22
  • تعداد عناوین: 10
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  • Angelica Silva, Sonia Martinez Gallegos*, Genoveva Rosano Ortega, Pablo Schabes Retchkiman, Carlos Vega Lebrun, Veronica Albiter Pages 1-12
    Nanomaterials are widely used in health and biomedical applications, however, only a few studies investigate their toxic effects. The present report signifies a contribution to the study of the toxic effects of silver nanoparticles on E. coli cells, which is a model organism of anthropogenic pollution. The toxicity of nanoparticles depends on their chemical and surface properties, shape and size. Nanoparticles that have the same chemical composition but different shapes or sizes might have different effects on cells. In this work, Ag nanoparticles were biosynthesized with an Eichhornia crassipes biomass, and it was demonstrated for the first time, that the amounts of hydrolysable tannins in this plant, are directly related to the size, shape, structure and composition of the Ag nanoparticles ; furthermore, the toxic effect was studied using E. coli cell culture. The EC was divided in three sections, i.e. roots, stems and leaves. Particle aggregation seems to be influenced by the amount of tannins present in the biomass. For each plant part, the amounts of hydrolysable tannins were determined, the highest amounts of these chemicals were present in the leaves, and hence these Ag nanoparticles dissolutions were used for the nanotoxicity experiments. . The cytotoxicity of Ag nanoparticles in a suspension was tested using the Ag nanoparticles synthesized with leaves, against Escherichia Coli ATCC 25992 where the concentration that inhibited 100% of bacterial growth, was 5 mg/L in contrast with a commercial solution which needed 10mg/L of Ag. For the most part, the Ag nanoparticles seemed to be of a nearly spherical shape, although on closer examination were determined to be mainly polyhedral. Leaves biomass, produced mainly quantum dot nanoparticles with sizes below 10 nm and the Ag nanoparticles were mostly AgO. The cytotoxicity of Ag NPs in a suspension tested using the Ag nanoparticles on E. coli was highly effective towards inhibition of bacterial growth.
    Keywords: Silver Nanoparticles, Biosynthesis, Eichhornia crassipes, Hydrolysable Tannins, cytotoxicity, Escherichia coli
  • Elham Boorboor Azimi, Alireza Badiei *, Ghodsi Mohammadi Ziarani Pages 13-20
    Tris(3-bromo-acetylacetonato) chromium(III) as an inert and very stable complex with a good leaving group was synthesized using as-prepared Cr(acetylacetonate)3. Highly ordered nanoporous silica (LUS-1), with some great features, was functionalized with 3-aminopropyltriethoxysilane. Then the as-prepared product was modified with tris(3-bromo-acetylacetonato) chromium(III) under mild reaction condition. Results obtained from N2 adsorption desorption, and X-ray powder diffraction proved the successful anchoring of the Cr(III) complex inside the pores of LUS-1 without any distortion in the structure. The morphology and configuration of LUS-1 with Scanning electron microscope and Transmission electron microscopy and Energy-dispersive X-ray spectrum of the product were prepared. Mid and Far Infrared spectroscopy confirmed that the product was possibly an amine, formed by substitution addition of NH2 group on LUS-1, to C-Br in acac ligands and not a weak and non-stable Schiff base. Thermal stability of the species was assessed by thermogravimetric analysis. This novel method resulted in the formation of a stable covalently bonded acetylacetonate to the support that it can be used in acidic media or even in polar solvents without altering the structure.
    Keywords: Nanoporous silica, Mesoporous materials, LUS-1, Tris(3-bromo-acetylacetonato) chromium(III)
  • Debarati Dey *, Pradipta Roy, Debashis De Pages 21-31
    This paper presents Density Functional Theory and Non-Equilibrium Green’s Function based First Principles calculations to explore the sensing property of Adenine and Thymine based hetero-junction chins for Ammonia and Phosphine gas molecules. This modeling and simulation technique plays an important and crucial role in the fast growing semiconductor based nanotechnology field. The hetero-junction chain has been passed through the multi layer GaAs nanopore electrodes. It has been found that Current-Voltage characteristics of the bio-molecular chain highly depend during the foreign gas molecules adsorption. This Current-Voltage sensitivity has been raised upto 40 and 9.3 times with the presence of single Ammonia and Phosphine molecules respectively under the ultra low bias voltage application. Adsorption of single molecule Ammonia and Phosphine increases the conductivity of the heterogeneous bio-molecular chain at room temperature. The quantum ballistic transmission through the direct band gap semi-conductor material GaAs nanopore increases during the Ammonia and Phosphine gas adsorption by the heterogeneous chain. In this paper we attempt to present the molecular model sensor with circuit elements. The attractive potential of conductivity modulation suggests this heterogeneous bio-molecular chain as an application in future generation bio-sensor technology.
    Keywords: Adenine-Thymine chain, Ammonia, Phosphine nanosensor, DFT, GaAs nanopore, NEGF
  • Kambiz Hedayati *, Mojtaba Goodarzi, Davood Ghanbari Pages 32-39
    Fe3O4 nanostructures were synthesized via a facile hydrothermal reaction. The effect of various surfactants such as cationic and anionic on the morphology of the product was investigated. Magnetic nanoparticles were added to poly styrene for preparation of magnetic nanocomposite. Nanostructures were then characterized using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The magnetic properties of the samples were also investigated using vibrating sample magnetometer. The magnesium ferrite nanoparticles exhibit super paramagnetic behaviour at room temperature, with a saturation magnetization of 66 emu/g and a coercivity less than 5 Oe. Distribution of the magnetic nanoparticles into poly styrene matrix increases the coercivity. Nanoparticles appropriately enhanced flame retardant property of the PS matrix. Nanoparticles act as barriers which decrease thermal transport and volatilization during decomposition of the polymer.
    Keywords: Nanoparticles, Magnetic, Nanocomposite, Flame Retardancy
  • Meisam Hasanpoor, Houman Fakhr Nabavi, Mahmood Aliofkhazraei * Pages 40-46
    In present study we used five green plants for microwave assisted synthesis of Alumina nanoparticles from Aluminum nitrate. Structural characterization was studied using x-ray diffraction that showed semi- crystalline and possibly, amorphous structure. Fourier infrared spectroscopy was used to determine Al-O bond and functional groups responsible for synthesis of nanoparticles. FTIR confirmed existence of Al-O band and bio-functional groups, originated from plant extract. Morphology and size of nanoparticles were investigated using scanning electron microscopy, transmission electron microscopy and atomic force microscopy techniques. It was observed that nanoparticles have near-spherical shape. Average size of clusters of nanoparticles varied with different routes from of 60 nm to 300 nm. AFM images showed that Individual nanoparticles were less than 10 nm.
    Keywords: Al2O3, Chemical preparation, Microwave processing, Nanoparticle
  • Markasagayam Visagamani Arularasu, Rangasamy Sundaram, Chinnapan Maria Magdalane, Kasinathan Kanimozhi, Kaviyarasu Kasinathan*, Force Tefo Thema, Douglas Letsholathebe, Genene Tessema Mola, Malik Maaza Pages 47-56
    A humidity sensor thin film based on nanoporous PbWO4-WO3 composites has been prepared by spin coating technique with different weight ratio of PbWO4 (Pb) and WO3 (WO) (PWWO-01, PWWO-82, PWWO-64, PWWO-46, PWWO-28, PWWO-01) and their humidity sensing properties have also been investigated at different relative humidity (RH) in the range of 5% - 98% at room temperature with dc resistance. It is found that composite PWWO-28 show best humidity sensing properties with the sensitivity factor value of (Sf) 3733. The response and recovery time of humidity sensor are about 50 s and 120 s, respectively. High sensitivity, narrow hysteresis loop, rapid response and recovery, prominent stability and good repeatability are obtained. Synthesized PbWO4-WO3 composites were characterized by power X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, BET and photoluminescence studies. The photocatalytic result demonstrated photocatalytic efficiency of nonporous PWWO-28 composite. The antimicrobial activity of the composites was determined by disc diffusion method.
    Keywords: Composites, Lead tungstate, Relative humidity, Response, recovery, Thin film
  • Amin Ebadi *, Sanaz Shojaei Pages 57-63
    Unsubstituted phthalocyanines of Co, Fe and Mn supported on zinc oxide nanoparticles were prepared and were well characterized with X-ray diffraction and scanning electron microscopy. The oxidation of alcohols with tert-butylhydroperoxide, in the presence of metallophthalocyanines supported on zinc oxide nanoparticles was investigated. These MPc/ZnO nanocomposites were effective catalysts for the oxidation of alcohols such as cyclohexanol (83.4% conversion; 100% selectivity), benzyl alcohol (70.5% conversion; 100% selectivity) and hexanol (62.3% conversion; 100% selectivity). The influences of reaction time, various metals and type of substrates and oxidants on the oxidation of alcohols were also studied, and optimized conditions were investigated. Under these reaction conditions, the activity of the catalysts decreases in the following order: CoPc/nano-ZnO > FePc/nano-ZnO > MnPc/nano-ZnO. It shows that TBHP is more efficient oxidant due to weaker O-O bond with respect to H2O2 and the following order has been observed for the percentage of conversions of alcohols: 2º > benzylic > 1º.
    Keywords: Alcohols, Metallophthalocyanines, Oxidation, ZnO nanoparticles
  • Ashish Karn*, Nitesh Kumar, Sivanandam Aravindan Pages 64-76
    The current study reports some interesting growth of novel In2O3 nanostructures using ambient-controlled chemical vapor deposition technique in the presence of a strongly reducing hydrazine ambient. The experiments are systematically carried out by keeping either of the carrier gas flow rate or the source temperature constant, and varying the other. For each of the depositions, the growth is studied at three different locations downstream. In this paper, we report the growth of some novel nanostructures including nanodonuts, nanomushrooms, standing nanorods and long nanowires using ambient controlled chemical vapor deposition technique. Further, the nanostructures are characterized through scanning electron microscopy, transmission electron microscopy and x-ray diffraction. First, the growth of nanowires, octahedral and nanorods were verified to occur in oxidizing, inert and reducing ambient, respectively. However, a systematic variation of experimental parameters shows that different kinds of nanostructures can be obtained using highly reducing hydrazine ambient. Further, simultaneous growth of octahedral along with nanomushrooms and the hexagonal tip of the standing nanorods provides some insight into the growth mechanisms of these novel nanostructures. Possible growth mechanisms of the nanostructures are also discussed in detail.
    Keywords: Chemical Vapor Deposition, Growth ambient, Hydrazine, Indium Oxide
  • Gholamreza Nabiyouni *, Hamed Halakoui, Davood Ghanbari Pages 77-81
    The lead ferrite (PbFe12O19) nanoparticles were prepared by a simple and short time microwave method. Lead nitrate, iron nitrate nine hydrate, surfactants, and ethylene glycol were used as precursor materials. The effect of surfactants on the morphology and particle size of the magnetic products was investigated. The prepared magnetic products were studied by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Single phase hexagonal ferrite nanoparticles with average particle size of 50 nm were obtained in synthesize temperature of 850◦C. Alternating gradient force magnetometer approves magnetic property of the hexaferrite nanostructures. The values of both saturation magnetization and coercivity strongly depend on the particle sizes. The obtained hexagonal ferrite nanoparticles exhibit a hard magnetic feature with a suitable saturation magnetization.
    Keywords: Lead Ferrite, Microwave, Nanocomposites
  • Xu Liu, Yan Yang, Yunfei Han, Lihong Wang, Gang Chen, Xuechun Xiao, Yude Wang * Pages 82-87
    Single crystal ZnO microrods are deposited on the surface of Zn plate through corrosion of Zn plate by H2O2 which is a green neutral reagent and easy to transform to H2O and O2. The structure and morphology of the obtained ZnO microrods were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron diffraction. A thermodynamics mechanism was brought up. It was found that the transformation from Zn to ZnO is mainly attributed to that H2O2 possessing enough redox potential oxidizes the Zn. At the same time, the photodegradation properties of the obtained ZnO microrods array were also evaluated. The obtained wurtize-type ZnO microrods show an effective degradation for methyl orange under ultraviolet, and it keeps a good efficiency during the ten repeated photocatalytic tests. The results demonstrate a potential of obtained ZnO/Zn in real application of water pollutant photodegradation, making them promising candidates for the wastewater treatment.
    Keywords: Deposition, H2O2 corrosion, Photocatalyst, ZnO microrods, Zn plate