scholarly journals Synthesis and Antibacterial Testing of Silver/Poly (Ether Amide) Composite Nanofibers with Ultralow Silver Content

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Shuai Liang ◽  
Geng Zhang ◽  
Jianzhong Min ◽  
Junqiao Ding ◽  
Xingmao Jiang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Antimicrobial Properties ◽  
Scanning Calorimetry ◽  
X Ray ◽  
E Coli ◽  
Antimicrobial Materials ◽  
Transmission Electron ◽  
Antimicrobial Material ◽  
Testing Standards

Antimicrobial materials have attracted much attention all over the world. Herein, a new kind of antimicrobial material, poly (ether amide) (PebaxⓇ) nanofibers containing Ag nanoparticles, was prepared by electrospinning method. The Ag/PebaxⓇcomposites were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA) measurements. The antimicrobial properties of Ag/PebaxⓇcomposites againstEscherichia coli(E. coli; ATCC25922 and avirulent) andStaphylococcus aureus(S. aureus; ATCC6538 and avirulent) were evaluated by membrane adhering method. It was found that the Ag content played an important part in the antimicrobial ability of Ag/PebaxⓇcomposites. When the mass ratio of AgNO3to PebaxⓇin the precursor was 0.15‰, the inhibition rate can reach >99.9% and antimicrobial activity againstE. coliandS. aureuswas 5.8 and 5.6, respectively, exceeding the antimicrobial testing standards JIS Z 2801. The above results indicated that the Ag/PebaxⓇcomposite was a promising antimicrobial material that can be used in many applications.

scholarly journals Silver nanoparticles nucleated in NaOH-treated halloysite: a potential antimicrobial material

2021 ◽  
Vol 12 ◽  
pp. 798-807
Author(s):  
Yuri B Matos ◽  
Rodrigo S Romanus ◽  
Mattheus Torquato ◽  
Edgar H de Souza ◽  
Rodrigo L Villanova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Antimicrobial Properties ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Scanning Calorimetry ◽  
Medical Treatments ◽  
X Ray ◽  
E Coli ◽  
Transmission Electron

Despite all recent advances in medical treatments, infectious diseases remain dangerous. This has led to intensive scientific research on materials with antimicrobial properties. Silver nanoparticles (Ag-NPs) are a well-established solution in this area. The present work studied the nucleation of silver on halloysite substrates modified by chemical treatment with NaOH. The resulting stabilized Ag-NPs were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The nucleation was characterized by thermogravimetric analysis and differential scanning calorimetry. The antimicrobial properties of the Ag-NPs were investigated against E. coli and S. aureus. The potential of the Ag-NPs for industrial application was tested by dispersing them into low-density polyethylene. The importance of the chemical affinity between matrix and additive was tested through coating the Ag-NPs with dodecanethiol, a non-polar surfactant. The resulting composites were characterized by scanning electron microscopy and in terms of surface antimicrobial activity. The results demonstrate that the Ag-NPs synthesized in this work are indeed antimicrobial, and that it is possible to imbue a polymeric matrix with the antimicrobial properties of Ag-NPs.

scholarly journals Silver nanoparticles nucleated in NaOH treated halloysite: a potential antimicrobial material.

2021 ◽  
Author(s):  
Yuri B Matos ◽  
Rodrigo S Romanus ◽  
Mattheus Torquato ◽  
Edgar H de Souza ◽  
Rodrigo L Villanova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Antimicrobial Properties ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Scanning Calorimetry ◽  
Medical Treatments ◽  
X Ray ◽  
E Coli ◽  
Transmission Electron

Despite all recent advances in medical treatments, infectious diseases remain dangerous. This scenario has led to intense scientific research on materials with antimicrobial properties. Silver nanoparticles (Ag-NPs) are a well established solution in this area. The present work studied the nucleation of silver in halloysite substrates (HNT) modified by a NaOH chemical treatment. The resulting stabilized Ag-NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive x-ray spectroscopy (EDS). The nucleation was characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Ag-NPs antimicrobial properties were investigated against \textit{E. coli} and \textit{S. aureus}. The potential of Ag-NPs for industrial application was tested by dispersing them into low density polyethylene (LDPE). The importance of the chemical affinity between matrix and additive was tested coating Ag-NPs with dodecanethiol, a non-polar surfactant. The resulting composites were characterized by scanning electron microscopy (SEM) and in terms of surface antimicrobial activity. The results demonstrate that Ag-NPs synthesized in this work are indeed antimicrobial, and that it is possible to imbue a polymeric matrix with the Ag-NPs antimicrobial properties.

Study on the nature of the electrochemically synthesized hard Fe–15.4 mass% Ni–0.70 mass% C alloy film

2003 ◽  
Vol 18 (4) ◽  
pp. 840-847
Author(s):  
A. S. M. A. Haseeb ◽  
Y. Hayashi ◽  
M. Masuda ◽  
M. Arita
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Magnetic Measurements ◽  
Alloy Film ◽  
The State ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Electrochemically Deposited ◽  
Decomposition Behavior

Electrochemical synthesis of hard Fe–15.4 mass% Ni–0.70 mass% C alloy film with a hardness 750 HV was carried out from sulfate-based bath containing a small amount of citric acid and L-ascorbic acid. The nature of the alloy was investigated by different characterization techniques including x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, Mössbauer spectroscopy, differential scanning calorimetry, and magnetic measurements. The decomposition behavior of the alloy was also studied and compared with that of thermally prepared martensite. It was found that the electrochemically deposited Fe–Ni–C alloy exists in a state that is ahead of the freshly quenched state of martensite. It is suggested that the state of the electrochemically deposited Fe–15.4 mass% Ni–0.70 mass% C alloy corresponds to the state of thermal martensite, which had been heated to the preprecipitation stage of tempering.

Hydrodeoxygenation of stearic acid for the production of “green” diesel

2014 ◽  
Vol 3 (6) ◽  
Author(s):  
Antonina A. Stepacheva ◽  
Linda Zh. Nikoshvili ◽  
Esther M. Sulman ◽  
Valentina G. Matveeva
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Photoelectron Spectroscopy ◽  
Hypercrosslinked Polystyrene ◽  
Biodiesel Production ◽  
Scanning Calorimetry ◽  
Green Diesel ◽  
X Ray ◽  
Transmission Electron

AbstractThe current work is devoted to the second-generation biodiesel production via fatty acids catalytic hydrodeoxygenation (HDO). Pd-containing catalysts based on polymeric matrix of hypercrosslinked polystyrene (HPS) with different metal loading were investigated in the process. The catalysts were characterized by low-temperature nitrogen physisorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The selectivity of the process (regarding to

Antibacterial silver-diatomite nanocomposite ceramic with low silver release

2019 ◽  
Vol 20 (2) ◽  
pp. 633-643
Author(s):  
Xiaopeng Qi ◽  
Junwei Chen ◽  
Qian Li ◽  
Hui Yang ◽  
Honghui Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Water Treatment ◽  
Photoelectron Spectroscopy ◽  
Bactericidal Effect ◽  
Ceramic Filter ◽  
Ceramic Filters ◽  
X Ray ◽  
E Coli ◽  
Point Of Use ◽  
Silver Release

Abstract There is an urgent need for an effective and long-lasting ceramic filter for point-of-use water treatment. In this study, silver-diatomite nanocomposite ceramic filters were developed by an easy and effective method. The ceramic filters have a three-dimensional interconnected pore structure and porosity of 50.85%. Characterizations of the silver-diatomite nanocomposite ceramic filters were performed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Silver nanoparticles were confirmed to be formed in situ in the ceramic filter. The highest silver concentration in water was 0.24 μg/L and 2.1 μg/L in short- and long-term experiments, indicating very low silver-release properties of silver-diatomite nanocomposite ceramic filter. The nanocomposite ceramics show strong bactericidal activity. When contact time with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of 105 colony forming units (CFU)/mL exceeded 3 h, the bactericidal rates of the four different silver content ceramics against E. coli and S. aureus were all 100%. Strong bactericidal effect against E. coli with initial concentration of 109 CFU/mL were also observed in ceramic newly obtained and ceramic immersed in water for 270 days, demonstrating its high stability. The silver-diatomite nanocomposite ceramic filters could be a promising candidate for point-of-use water treatment.

scholarly journals pH-controlled synthesis of sustainable lauric acid/SiO2 phase change material for scalable thermal energy storage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shafiq Ishak ◽  
Soumen Mandal ◽  
Han-Seung Lee ◽  
Jitendra Kumar Singh
Keyword(s):  
Electron Microscopy ◽  
Phase Change ◽  
Lauric Acid ◽  
Photoelectron Spectroscopy ◽  
Phase Change Materials ◽  
Precursor Solution ◽  
Thermal Reliability ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heating And Cooling

AbstractLauric acid (LA) has been recommended as economic, eco-friendly, and commercially viable materials to be used as phase change materials (PCMs). Nevertheless, there is lack of optimized parameters to produce microencapsulated PCMs with good performance. In this study, different amounts of LA have been chosen as core materials while tetraethyl orthosilicate (TEOS) as the precursor solution to form silicon dioxide (SiO2) shell. The pH of precursor solution was kept at 2.5 for all composition of microencapsulated LA. The synthesized microencapsulated LA/SiO2 has been characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), and Transmission electron microscopy (TEM). The SEM and TEM confirm the microencapsulation of LA with SiO2. Thermogravimetric analysis (TGA) revealed better thermal stability of microencapsulated LA/SiO2 compared to pure LA. PCM with 50% LA i.e. LAPC-6 exhibited the highest encapsulation efficiency (96.50%) and encapsulation ratio (96.15%) through Differential scanning calorimetry (DSC) as well as good thermal reliability even after 30th cycle of heating and cooling process.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

Characterization of columns grown during KrF laser micromachining of Al2O3–TiC ceramics

2003 ◽  
Vol 18 (5) ◽  
pp. 1123-1130 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Laser Pulses ◽  
Formation Mechanisms ◽  
X Ray ◽  
Reducing Conditions ◽  
Transmission Electron ◽  
Column Formation ◽  
Krf Laser

This paper aims to contribute to the understanding of column formation mechanisms in Al2O3–TiC ceramics micromachined using excimer lasers. Chemical and structural characterization of columns grown in Al2O3–TiC composite processed with 200 KrF laser pulses at 10 J/cm2 was carried out by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Fully developed columns consist of a core of unprocessed material surrounded by an outer layer of Al2TiO5, formed in oxidizing conditions, and an inner layer, formed in reducing conditions, composed of TiC and Al3Ti or an AlTi solid solution. Possible mechanisms of column formation are discussed.

scholarly journals Green Synthesis of Feather-Shaped MoS2/CdS Photocatalyst for Effective Hydrogen Production

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Yang Liu ◽  
Hongtao Yu ◽  
Xie Quan ◽  
Shuo Chen
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Production ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance ◽  
Sulfur Source ◽  
X Ray ◽  
Transmission Electron ◽  
Microscopy Images ◽  
Effective Hydrogen ◽  
Better Than

MoS2/CdS photocatalyst was fabricated by a hydrothermal method for H2production under visible light. This method used low toxic thiourea as a sulfur source and was carried out at 200°C. Thus, it was better than the traditional methods, which are based on an annealing process at relatively high temperature (above 400°C) using toxic H2S as reducing agent. Scanning electron microscopy and transmission electron microscopy images showed that the morphologies of MoS2/CdS samples were feather shaped and MoS2layer was on the surface of CdS. The X-ray photoelectron spectroscopy testified that the sample was composed of stoichiometric MoS2and CdS. The UV-vis diffuse reflectance spectra displayed that the loading of MoS2can enhance the optical absorption of MoS2/CdS. The photocatalytic activity of MoS2/CdS was evaluated by producing hydrogen. The hydrogen production rate on MoS2/CdS reached 192 μmol·h−1. This performance was stable during three repeated photocatalytic processes.

scholarly journals Aluminum Nitride-Silicon Carbide Alloy Crystals Grown on SiC Substrates by Sublimation

2005 ◽  
Vol 10 ◽  
Author(s):  
Z. Gu ◽  
L. Du ◽  
J.H. Edgar ◽  
E.A. Payzant ◽  
L. Walker ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Original Source ◽  
X Ray ◽  
Alloy Crystal ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
Vapor Distribution ◽  
Uniform Composition

AlN-SiC alloy crystals, with a thickness greater than 500 µm, were grown on 4H- and 6H-SiC substrates from a mixture of AlN and SiC powders by the sublimation-recondensation method at 1860-1990 °C. On-axis SiC substrates produced a rough surface covered with hexagonal grains, while 6H- and 4H- off-axis SiC substrates with different miscut angles (8° or 3.68°) formed a relatively smooth surface with terraces and steps. The substrate misorientation ensured that the AlN-SiC alloy crystals grew two dimensionally as identified by scanning electron microscopy (SEM). X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the AlN-SiC alloys had the wurtzite structure. Electron probe microanalysis (EPMA) and x-ray photoelectron spectroscopy (XPS) demonstrated that the resultant alloy crystals had non-stoichiometric ratios of Al:N and Si:C and a uniform composition throughout the alloy crystal from the interface to the surface. The composition ratio of Al:Si of the alloy crystals changed with the growth temperature, and differed from the original source composition, which was consistent with the results predicted by thermodynamic calculation of the solid-vapor distribution of each element. XPS detected the bonding between Si-C, Si-N, Si-O for the Si 2p spectra. The dislocation density decreased with the growth, which was lower than 106 cm−2 at the alloy surface, more than two orders of magnitude lower compared to regions close to the crystal/substrate interface, as determined by TEM.

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