scholarly journals The Preparation and Study of Ethylene Glycol-Modified Graphene Oxide Membranes for Water Purification

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 188 ◽  
Author(s):  
Yang Zhang ◽  
Lin-Jun Huang ◽  
Jian-Guo Tang ◽  
Yao Wang ◽  
Meng-Meng Cheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Water Purification ◽  
Interlayer Spacing ◽  
Filtration Method ◽  
Vacuum Filtration ◽  
X Ray ◽  
Molecular Separation ◽  
Scanning Electron

In this work, graphene oxide (GO)/ethylene glycol (EG) membranes were designed by a vacuum filtration method for molecular separation and water purification. The composite membranes were characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The interlayer spacing of GO membranes (0.825 nm) and GO/EG membranes (0.634 nm) are measured by X-ray diffraction (XRD). Using the vacuum filtration method, the membrane thickness can be controlled by selecting the volume of the solution from which the membrane is prepared, to achieve high water permeance and high rejection of Rhodamine B (RhB). The membrane performance was evaluated on a dead-end filtration device. The water permeance and rejection of RhB of the membranes are 103.35 L m−2 h−1 bar−1 and 94.56% (GO), 58.17 L m−2 h−1 bar−1 and 97.13% (GO/EG), respectively. The permeability of GO/EG membrane is about 40 × 10−6 L m-1 h−1 bar−1. Compared with the GO membrane, the GO/EG membrane has better separation performance because of its proper interlayer spacing. In this study, the highest rejection of RhB (99.92%) is achieved. The GO/EG membranes have potential applications in the fields of molecular separation and water purification.

scholarly journals Understanding the degradation mechanism of rechargeable lithium/sulfur cells: a comprehensive study of the sulfur–graphene oxide cathode after discharge–charge cycling

2014 ◽  
Vol 16 (32) ◽  
pp. 16931-16940 ◽  
Author(s):  
Xuefei Feng ◽  
Min-Kyu Song ◽  
Wayne C. Stolte ◽  
David Gardenghi ◽  
Duo Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Degradation Mechanism ◽  
X Ray ◽  
Oxide Cathode ◽  
Lithium Sulfur ◽  
Scanning Electron ◽  
Comprehensive Study

Degradation mechanism of rechargeable lithium/sulfur-graphene oxide cell was studied using scanning electron microscopy and X-ray spectroscopy.

scholarly journals Synthesis and characterization of graphene oxide flakes for transparent thin films

2021 ◽  
Vol 22 (3) ◽  
pp. 595-601
Author(s):  
R.G. Abaszade ◽  
S.A. Mamedova ◽  
F.G. Agayev ◽  
S.I. Budzulyak ◽  
O.A. Kapush ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Indium Tin Oxide ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

We have synthesized large scale, thin, transparent graphene oxide (GO) flakes by Hummer’s method and investigated their suitability for fabrication of transparent nanocomposites. The GO flakes were comprehensively characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Raman spectroscopy and Differential Scanning Calorimetry (DSC). X-ray diffraction displayed the peak of graphene oxide at 9°degree, which is characteristic peak of GO in agreement with the literature results. Scanning Electron Microscopy images revealed that thin, transparent, flake form GO with 14,8 µm lateral size and 0,31µm thickness were synthesized. The comparison with literature results show that for the first time, our group could synthesize large scale, thin and more transparent GO flakes by simple Hummer’s method using simple dispersed graphite. EDX measurements indicate the formation of layered structure with oxygen containing functional groups. The intensity ratio between D and G peaks in the Raman spectra proves that less defective GO flakes have been synthesized. The solution ability of the synthesized material indicate that high quality GO flakes were synthesized, which make them effective soluble material due to oxygen containing groups formed on the graphene plane during synthesis process.DSC results shows that these flakes are thermally stable till 200°C.  Due to high solubility properties, large scale and transparency they can be very useful in fabrication of high optical transparent nanocompoties for replacement indium tin oxide transparent conductors in solar panels, biomedical applications and microwave absorbers for electromagnetic interference (EMI) environmental protection.

The Synthesis of Graphene Oxide via Electrochemical Exfoliation Method

2015 ◽  
Vol 1109 ◽  
pp. 55-59 ◽  
Author(s):  
Nurhafizah Md Disa ◽  
Suriani Abu Bakar ◽  
S. Alfarisa ◽  
Azmi Mohamed ◽  
Illyas Md Isa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Sodium Dodecyl ◽  
Electrochemical Exfoliation ◽  
Spectra Analysis ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Scanning Electron

In this study, electrochemical exfoliation method was adopted in the production of graphene oxide (GO). The electrolyte used was sodium dodecyl sulphate (SDS) aqueous solution at various concentrations from 0.001 to 1.0 M. The effect of SDS concentrations on the morphology of GO samples were characterized using field emission scanning electron microscopy (FESEM), energy dispersive X-ray, micro-Raman and UV-Vis spectroscopy. As evident by the FESEM analysis, the concentration of SDS does give effect to the GO obtained in this study. The lowest GO production is given by the lowest concentration of SDS used which is 0.001 M. However, in term of ID/IGratio, the sample prepared at 0.001 M has the lowest value (0.33) as compared to the sample prepared with highest SDS concentration of 1.0 M (ID/IG~1.12). Meanwhile, the presence of absorbance peaks in the range of 224-237 nm from UV-Vis spectra analysis were seen for the whole samples and this indicate the formation of GO.

scholarly journals Graphene Oxide Films Obtained by Vacuum Filtration: X-Ray Diffraction Evidence of Crystalline Reorganization

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Julia L. S. Gascho ◽  
Sara F. Costa ◽  
Abel A. C. Recco ◽  
Sérgio H. Pezzin
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Interplanar Distance ◽  
Cellulose Membrane ◽  
X Ray Diffraction ◽  
Filtration Method ◽  
Vacuum Filtration ◽  
X Ray ◽  
Transmission Electron ◽  
Oxygen Groups

In this study, films of graphene oxide and chemically or thermally reduced graphene oxide were produced by a simple vacuum filtration method and submitted to a thorough characterization by X-ray diffraction (XRD), Raman and infrared spectroscopies, field-emission scanning electron microscopy, transmission electron microscopy, atomic force microscopy, confocal microscopy, and contact angle measurements. Graphene oxide (GO) was produced from graphite by the modified Hummers method and thereafter reduced with NaBH4 or by heating under argon in a tubular furnace. The films were produced from aqueous solutions by vacuum filtration on a cellulose membrane. Graphite presents two characteristic XRD peaks corresponding to d=0.34 nm and d=0.17 nm. After oxidation, only a peak at d=0.84 nm is found for powder GO, confirming the insertion of oxygen groups with an increase in the interplanar distance of graphene nanoplatelets. However, for GO films, other unexpected peaks are observed at d=0.63 nm, d=0.52 nm, and d=0.48 nm. After reduction, both chemical and thermal, the peak at 0.84 nm disappears, while those corresponding to interplanar distances of 0.63 nm, 0.52 nm, and 0.48 nm are still present. The other characterizations confirm the production and chemical composition of GO and reduced GO films. The results indicate the combination of crystalline regions with different interplanar distances, suggesting the ordering of graphene/graphene oxide intercalated sheets.

scholarly journals Novel CaMoO4@GO Nanocomposite: Synthesis, Characterization, and Investigation its Photocatalytic Properties

2020 ◽  
pp. 87-95
Author(s):  
Seyed Mostafa Hosseinpour Mashkani
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Methylene Blue ◽  
Graphene Oxide ◽  
Photocatalytic Properties ◽  
Energy Dispersive Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Molybdate ◽  
Scanning Electron

The current study aims to synthesize and characterize Calcium Molybdate-Graphene Oxide (CaMoO4@GO) nanocomposite under ultrasonic irradiation. Primarily, degradation of Methylene blue (MB) under Uv-Vis light was investigated to measure the photocatalytic properties of the as-synthesized CaMoO4@GO nanocomposite. In addition, various graphene oxide concentrations were applied to investigate its impact on the optical and photodegradation properties of calcium molybdate. X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectra energy dispersive analysis of X-ray (EDS) were used to characterize CaMoO4@GO nanocomposite. DRS results demonstrated that GO influenced significantly the optical properties of CaMoO4 as much as band gap of CaMoO4@GO nanocomposite shows a redshift in comparison with pure CaMoO4. Consequently, photocatalytic results demonstrated that adding GO causes to increase photodegradation of MB form 65% (CaMoO4) to 89% (CaMoO4@GO).

scholarly journals Co2TiO4/Reduced Graphene Oxide Nanohybrids for Electrochemical Sensing Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1611
Author(s):  
Constanza J. Venegas ◽  
Fabiana A. Gutierrez ◽  
Marcos Eguílaz ◽  
José F. Marco ◽  
Nik Reeves-McLaren ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Hybrid Materials ◽  
X Ray ◽  
Reduced Graphene ◽  
Scanning Electron

For the first time, the synthesis, characterization, and analytical application for hydrogen peroxide quantification of the hybrid materials of Co2TiO4 (CTO) and reduced graphene oxide (RGO) is reported, using in situ (CTO/RGO) and ex situ (CTO+RGO) preparations. This synthesis for obtaining nanostructured CTO is based on a one-step hydrothermal synthesis, with new precursors and low temperatures. The morphology, structure, and composition of the synthesized materials were examined using scanning electron microscopy, X-ray diffraction (XRD), neutron powder diffraction (NPD), and X-ray photoelectron spectroscopy (XPS). Rietveld refinements using neutron diffraction data were conducted to determine the cation distributions in CTO. Hybrid materials were also characterized by Brunauer–Emmett–Teller adsorption isotherms, Scanning Electron microscopy, and scanning electrochemical microscopy. From an analytical point of view, we evaluated the electrochemical reduction of hydrogen peroxide on glassy carbon electrodes modified with hybrid materials. The analytical detection of hydrogen peroxide using CTO/RGO showed 11 and 5 times greater sensitivity in the detection of hydrogen peroxide compared with that of pristine CTO and RGO, respectively, and a two-fold increase compared with that of the RGO+CTO modified electrode. These results demonstrate that there is a synergistic effect between CTO and RGO that is more significant when the hybrid is synthetized through in situ methodology.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Scanning Electron Microscopy and X-Ray Analyses of Dental Tissues from a Hibernator

1976 ◽  
Vol 34 ◽  
pp. 178-179
Author(s):  
M. L. Zimny ◽  
A. C. Haller
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Body Temperature ◽  
Ground Squirrel ◽  
Alveolar Bone ◽  
X Ray ◽  
Dental Tissues ◽  
Bone Minerals ◽  
Apical Tooth ◽  
Scanning Electron

During hibernation the ground squirrel is immobile, body temperature reduced and metabolism depressed. Hibernation has been shown to affect dental tissues varying degrees, although not much work has been done in this area. In limited studies, it has been shown that hibernation results in (1) mobilization of bone minerals; (2) deficient dentinogenesis and degeneration of alveolar bone; (3) presence of calculus and tears in the cementum; and (4) aggrevation of caries and pulpal and apical tooth abscesses. The purpose of this investigation was to study the effects of hibernation on dental tissues employing scanning electron microscopy (SEM) and related x-ray analyses.

Scanning Electron Microscopy and x-ray analysis of microparticles and early hydration effects

1995 ◽  
Vol 53 ◽  
pp. 692-693
Author(s):  
Yun Lu ◽  
David C. Joy
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Morphological Development ◽  
Early Hydration ◽  
X Ray ◽  
Blended Cements ◽  
Powder Particles ◽  
Chemical Wastes ◽  
Scanning Electron

High resolution scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDXA) were performed to investigate microparticles in blended cements and their hydration products containing sodium-rich chemical wastes. The physical appearance of powder particles and the morphological development at different hydration stages were characterized by using high resolution SEM Hitachi S-900 and by SEM S-800 with a EDX spectrometer. Microparticles were dispersed on the sample holder and glued by 1% palomino solution. Hydrated bulk samples were dehydrated by acetone and mounted on the holder by silver paste. Both fracture surfaces and flat cutting sections of hydrating samples were prepared and examined. Some specimens were coated with an 3 nm thick Au-Pd or Cr layer to provide good conducting surfaces. For high resolution SEM S-900 observations the accelerating voltage of electrons was 1-2 KeV to protect the electron charging. Microchemical analyses were carried out by S800/EDS equipped with a LINK detector of take-off angle =40°.

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