Size-Controlled Synthesis of MgO Nanoparticles and the Assessment of Their Bactericidal Capacity

2013 ◽  
Vol 1547 ◽  
pp. 135-140 ◽  
Author(s):  
Yarilyn Cedeño-Mattei ◽  
Myrna Reyes ◽  
Oscar Perales-Pérez ◽  
Félix R. Román
Keyword(s):  
Average Crystallite Size ◽  
Cost Effective ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
Mgo Nanoparticles ◽  
E Coli ◽  
Mechanism Of Inhibition ◽  
Crystallite Sizes ◽  
Nanoscale Mgo ◽  
Size Controlled

ABSTRACTThe present work focuses on the development of a reproducible and cost-effective size-controlled synthesis route for nanoscale MgO and the preliminary assessment of its bactericide capacity as a function of crystal size. Nanoscale MgO was produced through the thermal decomposition of Mg-carbonate hydrate precursor (hydromagnesite) synthesized in aqueous phase. The exclusive formation of the MgO phase, with an average crystallite size between 7 and 13 ± 1 nm, was evidenced by X-Ray Diffraction and HRTEM analyses. Fourier Transform – Infrared spectroscopy confirmed the evolution of the precursor into the desired MgO structure. The bactericidal tests were conducted by measuring the optical density at 600 nm of E. coli in presence of MgO nanoparticles of specific sizes. MgO nanocrystals with average crystallite sizes of 13nm inhibited bacterial growth up to 35% at 500 mg MgO/L. The mechanism of inhibition could be attributed to the formation of superoxide species on the MgO surface.

High Aspect Ratio Hydroxyapatite Nanorods Formed by Polymer Assisted Synthesis

2014 ◽  
Vol 508 ◽  
pp. 52-55
Author(s):  
A. Joseph Nathanael ◽  
R. Yuvakkumar ◽  
Tae Hwan Oh ◽  
Sun Ig Hong
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Morphological Analysis ◽  
Polymer Concentration ◽  
Xrd Analysis ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Length Width ◽  
Size Controlled

High aspect ratio (length/width) of hydroxyapatite (HA) nanorods were prepared by polymer assisted hydrothermal synthesis. The aspect ratio of the nanorods was increased in the presence of polymer in hydrothermal method. Structural analysis was carried out by X-ray diffraction (XRD) analysis to find the purity and the crystal structure of the material. Morphological analysis was carried out by field emission scanning electron microscope (FESEM) to find the morphological variation in the presence of polymer concentration compared to pristine HA. The increased aspect ratio of the HA was visible from the morphological analysis. This shape and size controlled synthesis have an important impact in many field of research.

Size-controlled Synthesis of Gold Nanoparticles by Thermolysis of a Gold(I)-Sulfide Complex in the Presence of Alkylamines

2009 ◽  
Vol 64 (11-12) ◽  
pp. 1305-1311 ◽  
Author(s):  
Mari Yamamoto ◽  
Yukiyasu Kashiwagi ◽  
Masami Nakamoto
Keyword(s):  
Gold Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Thermal Analyses ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkyl Chains ◽  
Transmission Electron ◽  
Gas Chromatography Mass Spectroscopy ◽  
Size Controlled

A size-controlled synthesis of gold nanoparticles has been developed by the thermolysis of AuCl(SMe2) in the presence of alkylamines at 120 °C. In the procedure, the key intermediate was [Au(NH2R)2]Cl, detected by electrospray ionization (ESI) mass spectrometry. This thermally unstable intermediate was reduced by alkylamines under mild conditions to produce alkylamine-capped gold nanoparticles. The average diameters of the gold nanoparticles could be regulated in a range from 4.3 to 6.1 nm by applying primary alkylamines with alkyl chains of different lengths. Larger gold nanoparticles with diameters from 10 to 22 nm were prepared by a combination of alkylamines and alkylcarboxylic acids with various lengths of the alkyl chains. The gold nanoparticles were characterized by transmission electron microscopy (TEM), UV/Vis absorption spectroscopy, powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), gas chromatography/mass spectroscopy (GC/MS), and thermogravimetric and differencial thermal analyses (TG/DTA)

scholarly journals Size-Controlled Synthesis of Fe3O4Magnetic Nanoparticles in the Layers of Montmorillonite

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Katayoon Kalantari ◽  
Mansor B. Ahmad ◽  
Kamyar Shameli ◽  
Mohd Zobir Bin Hussein ◽  
Roshanak Khandanlou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Average Diameter ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Interlamellar Space ◽  
Size Controlled ◽  
Chemical Coprecipitation Method

Iron oxide nanoparticles (Fe3O4-NPs) were synthesized using chemical coprecipitation method. Fe3O4-NPs are located in interlamellar space and external surfaces of montmorillonite (MMT) as a solid supported at room temperature. The size of magnetite nanoparticles could be controlled by varying the amount of NaOH as reducing agent in the medium. The interlamellar space changed from 1.24 nm to 2.85 nm and average diameter of Fe3O4nanoparticles was from 12.88 nm to 8.24 nm. The synthesized nanoparticles were characterized using some instruments such as transmission electron microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, field emission scanning electron microscopy, vibrating sample magnetometer, and Fourier transform infrared spectroscopy.

Nanoscale Topography of GC/Pt-C and GC/Pt-Ru-C Electrodes Studied by Means of STM, AFM and XRD Methods

2006 ◽  
Vol 518 ◽  
pp. 271-276 ◽  
Author(s):  
A. Kowal ◽  
P. Olszewski ◽  
D.V. Tripković ◽  
R. Stevanović
Keyword(s):  
Crystallite Size ◽  
Surface Area ◽  
Rietveld Method ◽  
High Surface ◽  
High Surface Area ◽  
Average Crystallite Size ◽  
X Ray Diffraction ◽  
Crystallite Sizes ◽  
Nanoscale Topography ◽  
Two Phases

Electrodes, assigned as GC/Pt-C and GC/Pt-Ru-C, were formed by deposition of Ptbased catalysts (47.5 wt % Pt + high surface area carbon) and (54 wt. % Pt-Ru alloy + high surface area carbon) on glassy carbon (GC) discs. X-ray diffraction measurements were used for the determination of the average crystallite size and phase composition of both catalysts. Crystallite size for Pt-C catalyst was 2.9 nm for Pt-fcc. In the diffraction pattern of the Pt-Ru-C catalyst two phases, e.g. Pt-Ru-fcc and Ru-hcp were refined using the Rietveld method. Crystallite sizes were 3.9 nm for Pt-Ru-fcc and 2.8 nm for Ru-hcp. STM observations of the surface of GC/Pt-C and GC/Pt-Ru-C electrodes revealed the presence of metal particles of the size in the range 2-6 nm and Pt-C or Pt- Ru-C agglomerates in the range of several tenth of nm. The thickness of the Nafion covering layer determined by AFM is ca. 100 nm. A simplified scheme of the investigated electrodes was created.

Increasing the Photocatalytic Activity by Mechano-chemically Milling on Zn- Doped TiO2

2009 ◽  
Vol 1217 ◽  
Author(s):  
Chennan Li ◽  
Sesha Srinivasan ◽  
Paula Algarin ◽  
Nikolai Kislov ◽  
Ayala Phani ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Sol Gel ◽  
Average Crystallite Size ◽  
Cost Effective ◽  
Blue Shift ◽  
High Energy ◽  
Planetary Mill ◽  
Photocatalytic Decomposition ◽  
X Ray Diffraction ◽  
Quantum Size

AbstractThis paper pursed one new cost effective strategy to improve the photocatalytic activity of the sol-gel developed Zn doped TiO2 by mechano-chemically milling in high energy planetary mill. The results showed that the photocatlytic activity was improved two times due to the increase of the surface area and the decrease in average crystallite size at the same time after using the high energy ball milling. Kubelka-Munk spectra of pristine and ball milled samples revealed a blue shift from 3.2 eV to 3.35 eV, which may be because of the presence of quantum size effects. SEM microstructural investigations revealed variations in the surface morphology with different Zn doping concentrations in the TiO2-Xwt.% Zn nanoparticulates. EDS spectra of these samples confirmed the stoichiometric concentration of Zn. Other characterization including X-ray diffraction (XRD), BET surface and the photocatalytic decomposition were also studied and the results were in agreement with each other.

Nickel Oxide-incorporated Polyaniline/Polyvinyl Alcohol Composite for Enhanced Antibacterial Activity

2019 ◽  
Vol 233 (9) ◽  
pp. 1261-1274 ◽  
Author(s):  
Gul Rahman ◽  
Mansoor Khan ◽  
Zahid Khan ◽  
Anwar-ul-Haq Ali Shah ◽  
Muhammad Saleem Khan ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Polyvinyl Alcohol ◽  
Nickel Oxide ◽  
Antibacterial Agent ◽  
Composite Films ◽  
Cost Effective ◽  
Single Step ◽  
Bacterial Strains ◽  
X Ray Diffraction ◽  
E Coli

Abstract The development of biocompatible, cost effective and more efficient materials to control or inhibit the growth of microorganisms in necessary to fight against resistant microbes. Here, we demonstrate the synthesis of nickel oxide-incorporated polyaniline/polyvinyl alcohol (PANI/PVA/NiOx) composite material by single-step polymerization and its application as antibacterial agent. The composite films were characterized using UV-visible spectroscopy (UV-Vis), Thermogravimetric analysis (TGA), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). UV-Vis spectra revealed the enhancement in absorption properties of PANI/PVA/NiOx with optimum 5% incorporation of NiOx. TGA results indicated slightly enhanced thermal stability of the PANI/PVA/NiOx composite film as compared to PANI/PVA. FTIR spectra for composites revealed the existence of NiOx in polymers. However the crystallinity of PANI/PVA was not much affected. The antibacterial activity of the prepared composites was examined against four different gram negative bacteria, Salmonella, Shigella, Pseudomonas and Escherichia coli (E. coli). The composite exhibited excellent antibacterial activity against E. coli, Salmonella and Shigella while pseudomonas showed some resistance. Based on the results, PANI/PVA/ NiOx (5%) composite showed the highest activity against the tested bacterial strains, thus showing its potential to be used as an effective antibacterial agent.

Electrochemical study of Nickel Oxide (NiO) nanoparticles from cactus plant extract

MRS Advances ◽  
2020 ◽  
Vol 5 (21-22) ◽  
pp. 1095-1102 ◽  
Author(s):  
Henok Gebretinsae ◽  
Giday Welegergs ◽  
N. Matinise ◽  
M. Maaza ◽  
Z. Y. Nuru
Keyword(s):  
Nickel Oxide ◽  
Plant Extract ◽  
Average Crystallite Size ◽  
Cost Effective ◽  
X Ray Diffraction ◽  
Cyclic Voltammetric ◽  
Nanosized Powders ◽  
Cyclic Voltammetric Study ◽  
Reversible Redox ◽  
P Type

ABSTRACTP-type NiO powders with an average crystallite size of 16 nm as shown by x-ray diffraction analysis were produced via biosynthesis using cactus plant extract. SEM showed that the NiO powders consisted of particles with sizes in the 20-35 nm range. A cyclic voltammetric study of the NiO nanopowders showed a quasi-reversible redox processes with the NiO powder showing potential for pseudo capacitance. Through these findings the use of natural Cactus extracts is hereby shown to be a cost-effective and environmentally friendly alternative for preparing Nickel oxide nanosized powders that can be of use in a variety of energy storage applications.

A FACILE SYNTHESIS OF SHAPE- AND SIZE-CONTROLLED α-Fe2O3 NANOPARTICLES THROUGH HYDROTHERMAL METHOD

NANO ◽  
2011 ◽  
Vol 06 (05) ◽  
pp. 469-479 ◽  
Author(s):  
GUANG-HUI WANG ◽  
WEN-CUI LI ◽  
KUN-MING JIA ◽  
AN-HUI LU ◽  
MATHIAS FEYEN ◽  
...  
Keyword(s):  
Amino Acids ◽  
Side Chain ◽  
Controlled Synthesis ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Facile Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Size Controlled ◽  
Shape And Size

α- Fe 2 O 3 nanoparticles have wide-ranging applications such as in catalysis, sensoring, painting, etc. This is the reason to study their controlled synthesis. Here we have investigated the synthesis of uniform α- Fe 2 O 3 nanoparticles using amino acids as morphology control agents. The products were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetry (TG) and differential thermal analysis (DTA). It was found that the type and the amount of amino acids as well as the reaction temperatures have significant influence on the shape and size of the obtained α- Fe 2 O 3 nanoparticles. The use of acidic amino acids (always contain C = O in the side chain) typically leads to the formation of α- Fe 2 O 3 nanoparticles with spindle shape. However, rhombohedrally shaped α- Fe 2 O 3 nanoparticles were formed in presence of basic amino acids (always contain - NH 2 in the side chain). Increasing the amount of amino acid generally results in α- Fe 2 O 3 nanoparticles with decreasing particle sizes.

scholarly journals Preparation and Characterization of Developed CuxSn1−xO2 Nanocomposite and Its Promising Methane Gas Sensing Properties

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2257 ◽  
Author(s):  
Nagih Shaalan ◽  
Dalia Hamad ◽  
Abdullah Aljaafari ◽  
Atta Abdel-Latief ◽  
Mostafa Abdel-Rahim
Keyword(s):  
Gas Sensing ◽  
Average Crystallite Size ◽  
Cost Effective ◽  
Emission Peak ◽  
X Ray Diffraction ◽  
High Concentration ◽  
X Ray ◽  
Sensing Properties ◽  
Low Concentrations ◽  
High Concentrations

Novel materials with nanostructures are effective in controlling the physical properties needed for specific applications. The use of active and sensing materials is increasing in many applications, such as gas sensing. In the present work, we attempted to synthesize incorporated Cu2+ into the SnO2 matrix as CuxSn1−xO2 nanocomposite using a cost-effective precursor and method. It was observed that, at low concentrations of copper precursor, only SnO2 phase could be detected by X-ray diffraction (XRD). The distribution of Cu in the SnO2 matrix was further measured by elemental analysis of energy-dispersive X-ray (EDX) mapping and X-ray fluorescence (XRF). At high copper concentration, a separated monoclinic phase of CuO was formed (noted here as CuO/SnO2). The average crystallite size was slightly reduced from 5.9 nm to 4.7 nm with low doping of 0.00–5.00% Cu but increased up to 15.0 nm at high doping of 10.00% Cu upon the formation of separated SnO2 and CuO phases. The formation of Cu–SnO2 or CuO phases at low and high concentrations was also observed by photoluminescent spectra. Here, only the emission peak of SnO2 with a slight blueshift was recorded at low concentrations, while only the CuO emission peak was recorded at high concentration. The effect of Cu concentration on the sensing properties of SnO2 toward methane (CH4) gas was also investigated. It was found that the sensor embedded with 2.00% Cu exhibited an excellent sensitivity of 69.0 at 350 °C and a short response–recovery time compared with the other sensors reported here. The sensing mechanism of CuxSn1−xO2 and CuO/SnO2 is thus proposed based on Cu incorporation.

scholarly journals Magnetic Combined Cross-Linked Enzyme Aggregates of Ketoreductase and Alcohol Dehydrogenase: An Efficient and Stable Biocatalyst for Asymmetric Synthesis of (R)-3-Quinuclidinol with Regeneration of Coenzymes In Situ

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 334 ◽  
Author(s):  
Yuhan Chen ◽  
Qihua Jiang ◽  
Lili Sun ◽  
Qiang Li ◽  
Liping Zhou ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Glucose Dehydrogenase ◽  
Enantiomeric Excess ◽  
Cost Effective ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
Sem Images ◽  
E Coli ◽  
Direct Immobilization

Enzymes are biocatalysts. In this study, a novel biocatalyst consisting of magnetic combined cross-linked enzyme aggregates (combi-CLEAs) of 3-quinuclidinone reductase (QNR) and glucose dehydrogenase (GDH) for enantioselective synthesis of (R)-3-quinuclidinolwith regeneration of cofactors in situ was developed. The magnetic combi-CLEAs were fabricated with the use of ammonium sulfate as a precipitant and glutaraldehyde as a cross-linker for direct immobilization of QNR and GDH from E. coli BL(21) cell lysates onto amino-functionalized Fe3O4 nanoparticles. The physicochemical properties of the magnetic combi-CLEAs were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and magnetic measurements. Field emission scanning electron microscope (FE-SEM) images revealed a spherical structure with numerous pores which facilitate the movement of the substrates and coenzymes. Moreover, the magnetic combi-CLEAs exhibited improved operational and thermal stability, enhanced catalytic performance for transformation of 3-quinuclidinone (33 g/L) into (R)-3-quinuclidinol in 100% conversion yield and 100% enantiomeric excess (ee) after 3 h of reaction. The activity of the biocatalysts was preserved about 80% after 70 days storage and retained more than 40% of its initial activity after ten cycles. These results demonstrated that the magnetic combi-CLEAs, as cost-effective and environmentally friendly biocatalysts, were suitable for application in synthesis of (R)-3-quinuclidinol essential for the production of solifenacin and aclidinium with better performance than those currently available.

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