Kinetics of the Calcium Oxysulfides Reduction by Carbon Monoxide

2009 ◽  
Vol 283-286 ◽  
pp. 539-544 ◽  
Author(s):  
R.I. Gulyaeva ◽  
Evgeny N. Selivanov ◽  
A.N. Mansurova
Keyword(s):  
Experimental Data ◽  
Carbon Monoxide ◽  
Thermogravimetric Analysis ◽  
Kinetic Parameters ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
X Ray ◽  
Reduction Processes ◽  
Heating Up ◽  
Kinetics Of

The chemistry and the kinetics of the reduction of calcium containing CaFeSO and Ca2FeCuSO3) oxysulfides in a mixture of flowing gases that contains (75% CO) carbon monoxide and argon have been investigated by thermogravimetric analysis and X-ray diffraction. Experiments were carried out on the synthesized samples by heating up to 1270 K with heating rates of 5-20 K/min. The Netzsch Thermokinetics program was used for the analysis of the experimental data. Kinetic parameters of reduction processes are determined.

scholarly journals Hydrogen desorption kinetics of MgH2 synthesized from modified waste magnesium

2014 ◽  
Vol 32 (3) ◽  
pp. 385-390
Author(s):  
Aysel Kantürk Figen ◽  
Bilge Coşkuner ◽  
Sabriye Pişkin
Keyword(s):  
Hydrogen Desorption ◽  
Nitrogen Atmosphere ◽  
Desorption Kinetics ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Xrf Scanning ◽  
Isothermal Kinetic ◽  
Kinetics Of

AbstractIn the present study, hydrogen desorption properties of magnesium hydride (MgH2) synthesized from modified waste magnesium chips (WMC) were investigated. MgH2 was synthesized by hydrogenation of modified waste magnesium at 320 °C for 90 min under a pressure of 6 × 106 Pa. The modified waste magnesium was prepared by mixing waste magnesium with tetrahydrofuran (THF) and NaCl additions, applying mechanical milling. Next, it was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques in order to characterize its structural properties. Hydrogen desorption properties were determined by differential scanning calorimetry (DSC) under nitrogen atmosphere at different heating rates (5, 10, and 15 °C/min). Doyle and Kissenger non-isothermal kinetic models were applied to calculate energy (Ea) values, which were found equal to 254.68 kJ/mol and 255.88 kJ/mol, respectively.

Thermal degradation kinetics of oxo-degradable PP/PLA blends

2018 ◽  
Vol 39 (1) ◽  
pp. 58-67 ◽  
Author(s):  
Dev K. Mandal ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Kinetic Parameters ◽  
Degradation Kinetics ◽  
Nitrogen Atmosphere ◽  
Thermal Degradation Kinetics ◽  
Heating Rates ◽  
Kinetics Of

AbstractIn this article, the influence of polylactide and pro-oxidant on the thermal stability, degradation kinetics, and lifetime of polypropylene has been investigated using thermogravimetric analysis under nitrogen atmosphere at four different heating rates (i.e. 5, 10, 15, and 20°C/min). The kinetic parameters of degradation were studied over a temperature range of 30–550°C. The derivative thermogravimetric curves have indicated single stage and two stage degradation processes. The activation energy was evaluated by using the Kissinger, Kim-Park, and Flynn-Wall methods under the nitrogen atmosphere. The activation energy value of polypropylene was much higher than that of polylactide. Addition of polylactide and pro-oxidant in polypropylene decreased the activation energy. The lifetime of polypropylene has also decreased with the addition of polylactide and pro-oxidant.

Identification of a deleterious phase in photocatalyst based on Cd1 − xZnxS/Zn(OH)2by simulated XRD patterns

2017 ◽  
Vol 73 (3) ◽  
pp. 360-368 ◽  
Author(s):  
Svetlana Cherepanova ◽  
Dina Markovskaya ◽  
Ekaterina Kozlova
Keyword(s):  
Experimental Data ◽  
Thermogravimetric Analysis ◽  
Variable Temperature ◽  
Interlayer Distance ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Diffraction Peaks ◽  
Xrd Patterns

The X-ray diffraction (XRD) pattern of a deleterious phase in the photocatalyst based on Cd1 − xZnxS/Zn(OH)2contains two relatively intense asymmetric peaks withd-spacings of 2.72 and 1.56 Å. Very small diffraction peaks with interplanar distances of (d) ≃ 8.01, 5.40, 4.09, 3.15, 2.49 and 1.35 Å are characteristic of this phase but not always observed. To identify this phase, the XRD patterns for sheet-like hydroxide β-Zn(OH)2and sheet-like hydrozincite Zn5(CO3)2(OH)6as well as for turbostratic hydrozincite were simulated. It is shown that the XRD pattern calculated on the basis of the last model gives the best correspondence with experimental data. Distances between layers in the turbostratically disordered hydrozincite fluctuate aroundd≃ 8.01 Å. This average layer-to-layer distance is significantly higher than the interlayer distance 6.77 Å in the ordered Zn5(CO3)2(OH)6probably due to a deficiency of CO32−anions, excess OH−and the presence of water molecules in the interlayers. It is shown by variable-temperature XRD and thermogravimetric analysis (TGA) that the nanocrystalline turbostratic nonstoichiometric hydrozincite-like phase is quite thermostable. It decomposes into ZnO in air above 473 K.

Disordering and Reordering Kinetics of a Fe–40A1 B2 Alloy

1994 ◽  
Vol 364 ◽  
Author(s):  
S. Gialanella ◽  
M. D. Baró ◽  
L. Lutterotti ◽  
S. Suriñach
Keyword(s):  
Magnetic Measurements ◽  
High Energy ◽  
Defect Structures ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Energy Ball ◽  
Heating Up ◽  
Kinetics Of

AbstractThe ordered structure of Fe–40A1 B2 powders was completely disordered by high energy ball-milling. The defect structures of the powders disordered to different extents were characterized using X-Ray diffraction. A significant lattice expansion was observed, which we tried to relate to the high concentration of point defects introduced into the material as a consequence of milling.A complete reordering was accomplished by heating up the specimens under an inert Ar atmosphere. We followed the kinetics of the disorder to order transformation by Differential Scanning Calorimetry and Thermogravimetric Magnetic Measurements. The two techniques allowed us to identify the temperature range and the apparent activation energy of the process. As expected, a decrease in the magnetic moment of the originally disordered powders as a consequence of the reordering treatments was also observed.

scholarly journals Coordination polymers of Fe(III) with ligands derived from dinaphthyl-, dinaphthylthio- and dinaphthyldithiophosphinic acids

2002 ◽  
Vol 67 (8-9) ◽  
pp. 617-624 ◽  
Author(s):  
Ioan Rosca ◽  
Daniel Sutiman ◽  
Mihaela Vizitiu ◽  
Doina Sibiescu ◽  
Adrian Cailean ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Coordination Polymers ◽  
Gel Chromatography ◽  
Ir Absorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Decomposition Reactions ◽  
Structural Formulae

The synthesis and the study of some coordination polymers derived from the interaction of the acetylacetonate of Fe(III) with dinaphthylphosphinic acid, dinaphthylthiophosphinic acid and dinaphthyldithiophosphinic acid are presented. The methods applied for the study were chemical analysis, gel chromatography, M?ssbauer and IR absorption spectroscopy, X-ray diffraction and thermogravimetric analysis from which the kinedic parameters of the thermal decomposition reactions were determined. The semiconductive properties of the synthesized compounds were also examined. Based on the obtained experimental data and on literature indications, the structural formulae of these compounds were assigned.

scholarly journals Decomposition Characteristics and Kinetics of Microalgae in N2 and CO2 Atmospheres by a Thermogravimetry

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Xu Qing ◽  
Ma Xiaoqian ◽  
Yu Zhaosheng ◽  
Cai Zilin ◽  
Ling Changming
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Thermal Degradation ◽  
Apparent Activation Energy ◽  
Kinetic Parameters ◽  
Reaction Order ◽  
Heating Rates ◽  
Residual Mass ◽  
Second Stage ◽  
Kinetics Of

The thermal degradation characteristics of microalgae were investigated in highly purified N2 and CO2 atmospheres by a thermogravimetric analysis (TGA) under different heating rates (10, 20, and 40°C/min). The results indicated that the total residual mass in CO2 atmosphere (16.86%) was less than in N2 atmosphere (23.12%); in addition, the kinetics of microalgae in N2 and CO2 atmospheres could be described by the pseudo bicomponent separated state model (PBSM) and pseudo-multi-component overall model (PMOM), respectively. The kinetic parameters calculated by Coats-Redfern method showed that, in CO2 atmosphere, the apparent activation energy (E) of microalgae was between 9.863 and 309.381 kJ mol−1 and the reaction order (n) was varied from 1.1 to 7. The kinetic parameters (E,n) of the second stage in CO2 atmosphere were quite similar to those in N2 atmosphere.

Dimeric Liquid Crystalline Epoxy Resins Containing Azo Group: Mesogenic Behavior and Curing with Anhydride

2010 ◽  
Vol 123-125 ◽  
pp. 955-958
Author(s):  
De Wen Zhou ◽  
Li Yan Liang ◽  
Man Geng Lu
Keyword(s):  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Cure Kinetics ◽  
X Ray Diffraction ◽  
Melting Points ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Azo Group ◽  
Kinetics Of

A series of dimeric liquid crystalline (LC) epoxy monomers containing azo groups with different length of central spacers were synthesized. The mesogenic behavior of these monomers was characterized by differential scanning calorimetry(DSC), polarized optical microscopy (POM) and wide-angle X-Ray diffraction(WAXS). Like other dimeric LC epoxy monomers, the melting points, clear points and mesophase of these compounds were influenced by the carbon numbers of the central spacers. Cure kinetics of these monomers with anhydride was studied by non-isothermal DSC at different heating rates. With the increasing of conversion, the values of activation energy show a tendency to decrease. The formation and development of LC phase during curing were also studied by POM. Finally LC thermosets with nematic phase were obtained.

scholarly journals Stable and Metastable Phase Equilibria Involving the Cu6Sn5 Intermetallic

2021 ◽  
Author(s):  
A. Leineweber ◽  
M. Löffler ◽  
S. Martin
Keyword(s):  
Phase Equilibria ◽  
Electron Backscatter Diffraction ◽  
Metastable Phase ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Ordered Phases ◽  
Backscatter Diffraction ◽  
Kinetics Of

Abstract Cu6Sn5 intermetallic occurs in the form of differently ordered phases η, η′ and η′′. In solder joints, this intermetallic can undergo changes in composition and the state of order without or while interacting with excess Cu and excess Sn in the system, potentially giving rise to detrimental changes in the mechanical properties of the solder. In order to study such processes in fundamental detail and to get more detailed information about the metastable and stable phase equilibria, model alloys consisting of Cu3Sn + Cu6Sn5 as well as Cu6Sn5 + Sn-rich melt were heat treated. Powder x-ray diffraction and scanning electron microscopy supplemented by electron backscatter diffraction were used to investigate the structural and microstructural changes. It was shown that Sn-poor η can increase its Sn content by Cu3Sn precipitation at grain boundaries or by uptake of Sn from the Sn-rich melt. From the kinetics of the former process at 513 K and the grain size of the η phase, we obtained an interdiffusion coefficient in η of (3 ± 1) × 10−16 m2 s−1. Comparison of this value with literature data implies that this value reflects pure volume (inter)diffusion, while Cu6Sn5 growth at low temperature is typically strongly influenced by grain-boundary diffusion. These investigations also confirm that η′′ forming below a composition-dependent transus temperature gradually enriches in Sn content, confirming that Sn-poor η′′ is metastable against decomposition into Cu3Sn and more Sn-rich η or (at lower temperatures) η′. Graphic Abstract

scholarly journals Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus
Keyword(s):  
Experimental Data ◽  
Aspartic Acid ◽  
Ph Value ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Zeolite ◽  
X Ray ◽  
Slow Release Fertilizers ◽  
Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

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