Reactivity Towards O2 and NO of the Soot Formed from Ethylene Pyrolysis at Different Temperatures

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
M Pilar Ruiz ◽  
Alicia Callejas ◽  
Angela Millera ◽  
María U. Alzueta ◽  
Rafael Bilbao
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Gas Chromatography ◽  
Raman Spectroscopy ◽  
Residence Time ◽  
Formation Temperature ◽  
Influence Of Temperature ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Scanning Electron

The influence of temperature on the formation of soot from ethylene pyrolysis has been studied. Pyrolysis experiments were carried out in a quartz reactor in the 1000-1200 °C temperature range, for an inlet C2H4 concentration of 50000 ppmv and a gas residence time of 4552/T(K) seconds. Outlet gases were analyzed by gas chromatography and the amount of soot produced measured. The reactivity of the soot samples obtained towards O2 and NO was also studied. Results show that the higher the formation temperature, the less reactive the soot. The soot samples were further characterized using elemental analysis, scanning electron microscopy and Raman spectroscopy, in order to study their structural properties, and relate them to their reactivity. Additionally, a comparison of the reactivity towards NO between acetylene and ethylene soot samples obtained under similar conditions has been carried out. The soot samples obtained from ethylene pyrolysis present higher reactivity towards NO than the soot samples formed from acetylene.

Study of the Influence of Temperature on the Optical and Structural Properties of Dolomite

2020 ◽  
Vol 74 (10) ◽  
pp. 1280-1286
Author(s):  
Lucas Train Loureço ◽  
Celso de Araujo Duarte ◽  
Dietmar William Foryta ◽  
Bruno Guimarães Titon ◽  
Eleonora Maria Gouvêa Vasconcellos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Treatment ◽  
X Ray Diffraction ◽  
Electron Dispersive Spectroscopy ◽  
Influence Of Temperature ◽  
X Ray ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Scanning Electron

The present work reports the results of structural and optical investigations in samples of natural dolomite, subjected to thermal treatment at different temperatures (500 ℃ to 700 ℃) and times (one up to three hours). The motivation is the evaluation of the changes that may occur in carbonaceous asteroids and meteorites, respectively, subjected to the action of the solar radiation and heated during the fall in the atmosphere. We carried out scanning electron microscopy, electron dispersive spectroscopy, X-ray diffraction, optical reflectance and photoluminescence measurements

scholarly journals On the Rehydration of Organic Layered Double Hydroxides to Form Graphene-LDH Nanocomposites

2018 ◽  
Author(s):  
Eleonora Conterosito ◽  
Luca Palin ◽  
Diego Antonioli ◽  
Maria Pia Riccardi ◽  
Enrico Boccaleri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Memory Effect ◽  
X Ray ◽  
Thermogravimetric Data ◽  
Different Temperatures ◽  
Double Hydroxides ◽  
Ir And Raman ◽  
Scanning Electron

A graphene-containing LDH was prepared by re-hydration of the oxides produced by the calcination of an organic LDH. While the memory effect is a widely recognized effect on oxides produced by inorganic LDHs, it is unprecedented from the calcination/re-hydration of organic ones. Different temperatures (400, 600 and 1100 °C) were tested, on the basis of thermogravimetric data. Water instead of a carbonate solution was used for the re-hydration, with CO2 available from water itself and/or air to induce a slower process with an easier and better intercalation of the carbonaceous species within the layers. The samples were characterized by X-ray Powder Diffraction (XRPD), IR and Raman spectroscopy and scanning electron microscopy (SEM). XRPD indicate the presence of carbonate LDH mixed with a layered phase with a larger d-spacing. IR confirmed that the prevailing anion is carbonate, coming from the water used for the re-hydration and/or air. Raman data indicated the presence of low-ordered graphenic species moieties and SEM the absence of separated graphene of graphitic sheets, suggesting an intimate mixing of the carbonaceous phase with reconstructed LDH. Organic LDHs gave better memory effect after calcination at 400 °C. Conversely, the graphenic species are observed after rehydration of the sample calcined at 600 °C with a reduced memory effect, demonstrating the interference of the carbonaceous phase with LDH reconstruction and the bonding with LDH layers to form a graphene-LDH nanocomposite.

scholarly journals Sintering of anorthite based ceramics prepared from kaolin DD2 and calcite

Cerâmica ◽  
2016 ◽  
Vol 62 (364) ◽  
pp. 317-322 ◽  
Author(s):  
S. Zaiou ◽  
A. Harabi ◽  
E. Harabi ◽  
A. Guechi ◽  
N. Karboua ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Raw Materials ◽  
Bimodal Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fine Powders ◽  
Different Temperatures ◽  
Scanning Electron

Abstract In this work, the preparation of anorthite based ceramics using a modified milling system and 80 wt% kaolin (DD2 type) and 20 wt% calcium oxide extracted from CaCO3 is shown. The choice of these raw materials was dictated by their natural abundance. Previous studies have shown that a simple and vibratory multidirectional milling system using a bimodal distribution of highly resistant ceramics can be successfully used for obtaining fine powders. The prepared samples were sintered at different temperatures ranging between 800 and 1100 °C. It has been found that the relative density of samples sintered at 900 °C for 1 h with a heating rate of 5 °C/min was about 96% of the theoretical density of anorthite (2.75 g/cm3). Finally, the prepared samples were also characterized by scanning electron microscopy, X-ray diffraction and Raman spectroscopy.

scholarly journals Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

2014 ◽  
Vol 10 ◽  
pp. 1613-1619 ◽  
Author(s):  
Simon Rondeau-Gagné ◽  
Jules Roméo Néabo ◽  
Maxime Daigle ◽  
Katy Cantin ◽  
Jean-François Morin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Self Assembly ◽  
Significant Enhancement ◽  
Side Chains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Topochemical Polymerization ◽  
Scanning Electron

The synthesis and self-assembly of two new phenylacetylene macrocycle (PAM) organogelators were performed. Polar 2-hydroxyethoxy side chains were incorporated in the inner part of the macrocycles to modify the assembly mode in the gel state. With this modification, it was possible to increase the reactivity of the macrocycles in the xerogel state to form polydiacetylenes (PDAs), leading to a significant enhancement of the polymerization yields. The organogels and the PDAs were characterized using Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM).

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