scholarly journals Thermodynamics and Kinetic Modeling of the ZnSO4.H2O Thermal Decomposition in the Presence of a Pd/Al2O3 Catalyst

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 548
Author(s):  
Gabriela V. T. Kurban ◽  
Artur S. C. Rego ◽  
Nathalli M. Mello ◽  
Eduardo A. Brocchi ◽  
Rogério C. S. Navarro ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Zinc Sulfate ◽  
Thermodynamic Assessment ◽  
Reaction System ◽  
Decomposition Temperature ◽  
Kinetic Behavior ◽  
Proposed Model ◽  
Al2o3 Catalyst ◽  
Iodine Reaction

The sulfur–iodine thermochemical water-splitting cycle is a promising route proposed for hydrogen production. The decomposition temperature remains a challenge in the process. Catalysts, such as Pd supported on Al2O3, are being considered to decrease reaction temperatures. However, little is known regarding the kinetic behavior of such systems. In this work, zinc sulfate thermal decomposition was studied through non-isothermal thermogravimetric analysis to understand the effect of a catalyst within the sulfur–iodine reaction system context. The findings of this analysis were also related to a thermodynamic assessment. It was observed that the presence of Pd/Al2O3 modified the reaction mechanism, possibly with some intermediate reactions that were suppressed or remarkably accelerated. The proposed model suggests that zinc sulfate transformation occurred in two sequential stages without the Pd-based material. Activation energy values of 238 and 368 kJ.mol−1 were calculated. In the presence of Pd/Al2O3, an activation energy value of 204 kJ.mol−1 was calculated, which is lower than observed previously.

scholarly journals Hydrothermal Synthesis of Hematite Nanoparticles Decorated on Carbon Mesospheres and Their Synergetic Action on the Thermal Decomposition of Nitrocellulose

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 968 ◽  
Author(s):  
Abdenacer Benhammada ◽  
Djalal Trache ◽  
Mohamed Kesraoui ◽  
Salim Chelouche
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Analytical Techniques ◽  
Decomposition Reaction ◽  
Decomposition Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Catalyst ◽  
Average Size ◽  
A Minor

In this study, carbon mesospheres (CMS) and iron oxide nanoparticles decorated on carbon mesospheres (Fe2O3-CMS) were effectively synthesized by a direct and simple hydrothermal approach. α-Fe2O3 nanoparticles have been successfully dispersed in situ on a CMS surface. The nanoparticles obtained have been characterized by employing different analytical techniques encompassing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The produced carbon mesospheres, mostly spherical in shape, exhibited an average size of 334.5 nm, whereas that of Fe2O3 supported on CMS is at around 80 nm. The catalytic effect of the nanocatalyst on the thermal behavior of cellulose nitrate (NC) was investigated by utilizing differential scanning calorimetry (DSC). The determination of kinetic parameters has been carried out using four isoconversional kinetic methods based on DSC data obtained at various heating rates. It is demonstrated that Fe2O3-CMS have a minor influence on the decomposition temperature of NC, while a noticeable diminution of the activation energy is acquired. In contrast, pure CMS have a slight stabilizing effect with an increase of apparent activation energy. Furthermore, the decomposition reaction mechanism of NC is affected by the introduction of the nano-catalyst. Lastly, we can infer that Fe2O3-CMS may be securely employed as an effective catalyst for the thermal decomposition of NC.

Studies on Thermal Stability and Rheological Property of PU/PVDF Blend

2011 ◽  
Vol 311-313 ◽  
pp. 1065-1070
Author(s):  
Guo Lan Huan ◽  
Jian Li Liu ◽  
Qi Yun Du ◽  
Xiao Yu Hu
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Decomposition ◽  
Shear Stress ◽  
Rheological Property ◽  
Decomposition Temperature ◽  
Dynamic Equations ◽  
Thermal Decomposition Temperature ◽  
Thermal Stability Of ◽  
Decomposition Activation Energy

In this article, the thermal stability of PU/PVDF blend was investigated by thermogravimetry (TG), and their rheological property was studied through testing and analyzing the rheological curves. The results showed that, with the increase in PVDF content, the thermal decomposition temperature of PU/PVDF blend increased, and by fitting relevant data to thermal decomposition dynamic equations, it was found that thermal decomposition activation energy of the blend increased gradually, i.e. the thermal stability of the blend increased gradually. Meantime, based on the curves of shear stress vs. shear rate of the blend at 180°C and 200°C, it was shown that for PU/PVDF blend, with the decrease of temperature and the increase in PVDF content, the non-Newtonian index decreased, while the viscosity of the blend increased.

Thermal Degradation of Flame Retardant Cotton Cellulose

2010 ◽  
Vol 168-170 ◽  
pp. 380-383
Author(s):  
Ming Gao ◽  
Fa Chao Wu
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Differential Thermal Analysis ◽  
Thermal Degradation ◽  
Flame Retardant ◽  
Kinetic Parameters ◽  
Oxygen Index ◽  
Decomposition Temperature ◽  
Limiting Oxygen Index

Cellulose treated with flame retardant was studied by thermogravimetry (TG), differential thermal analysis (DTA), limiting oxygen index (LOI) and IR. The kinetic parameters for the thermal degradation are obtained following the method of Broido. For the flame retardant cellulose, the activation energy and decomposition temperature were much decreased while char yield and LOI were increased. The main thermal decomposition of the samples with higher LOI occurs at lower temperatures, while that with lower LOI occurs at higher temperatures.

scholarly journals Thermal Stability of Ionic Liquids: Current Status and Prospects for Future Development

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 337
Author(s):  
Chenqian Xu ◽  
Zhenmin Cheng
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Decomposition ◽  
Ionic Liquids ◽  
Isoconversional Methods ◽  
Decomposition Temperature ◽  
Current Status ◽  
Exponential Factor ◽  
Master Plots ◽  
Alkyl Side Chains

Ionic liquids (ILs) are the safest solvent in various high-temperature applications due to their non-flammable properties. In order to obtain their thermal stability properties, thermogravimetric analysis (TGA) is extensively used to analyze the kinetics of the thermal decomposition process. This review summarizes the different kinetics analysis methods and finds the isoconversional methods are superior to the Arrhenius methods in calculating the activation energy, and two tools—the compensation effect and master plots—are suggested for the calculation of the pre-exponential factor. With both parameters, the maximum operating temperature (MOT) can be calculated to predict the thermal stability in long-term runnings. The collection of thermal stability data of ILs with divergent cations and anions shows the structure of cations such as alkyl side chains, functional groups, and alkyl substituents will affect the thermal stability, but their influence is less than that of anions. To develop ILs with superior thermal stability, dicationic ILs (DILs) are recommended, and typically, [C4(MIM)2][NTf2]2 has a decomposition temperature as high as 468.1 °C. For the convenience of application, thermal stability on the decomposition temperature and thermal decomposition activation energy of 130 ILs are summarized at the end of this manuscript.

Kinetics and Thermodynamics Studies on the Decompositions of Phosphogypsum in Different Atmospheres

2010 ◽  
Vol 160-162 ◽  
pp. 842-848 ◽  
Author(s):  
Ping Ning ◽  
Shao Cong Zheng ◽  
Li Ping Ma ◽  
Ya Lei Du ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Kinetic Parameters ◽  
Decomposition Temperature ◽  
Kinetics And Thermodynamics ◽  
Xrd Method

In this study, the decomposition of phosphogypsum at different atmospheres of pure CO, N2 and 10% of CO were investigated to gain knowledge about the thermal decomposition of phosphogypsum. It was found that the starting decomposition temperature is 820°C in pure CO, the temperatures are 1080°C for N2 and 890°C for 10% of CO, respectively. Quantitative XRD method was applied to determine the amounts of CaSO4, CaO and CaS in the residues. The results indicate that CaS was mainly formed during Phosphogypsum decomposition in pure CO. In N2 CaO is the main residue from reactions, accompanying a small amount of CaS, and there are CaO and CaS in the decomposed productions, in 10% of CO. Moreover, The Starink,Kissinger and Flynn-Wall-Ozawa methods were used to calculate the kinetic parameters, respectively. The results have shown that the activation energy is in the range of 290.84-317.34 kJ/mol for in pure CO, 335.98-360.90 kJ/mol for 10% CO, 476.39 kJ/mol for N2.

Optothermal Property and Decomposition Characteristics of PtOx Ultrathin Film Sandwiched Between ZnS–SiO2 for Super-Resolution Near-Field Recording

2007 ◽  
Vol 7 (1) ◽  
pp. 374-380
Author(s):  
Yung-Chiun Her ◽  
Bou-Yin Liao ◽  
Wei-Chih Hsu ◽  
Song-Yeu Tsai
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Near Field ◽  
Super Resolution ◽  
Decomposition Temperature ◽  
Ultrathin Film ◽  
Field Structure ◽  
Field Recording ◽  
Mask Layer ◽  
Resolution Capability

We have investigated the optothermal property and decomposition characteristics of PtOx ultrathin film protected by ZnS–SiO2 layers and effects of the constituent phases of PtOx on super-resolution capability and read stability of the super-RENS disk. All the ZnS–SiO2/PtOx/ZnS–SiO2 multilayers exhibited a steep reflectivity drop at the temperature range between 265 and 350 °C, corresponding to the decomposition of PtOx. The decomposition temperature of the 4-nm-thick PtOx ultrathin film protected by ZnS–SiO2 layers was much lower than those obtained in thick PtOx films without protection. The activation energy for thermal decomposition was ∼1.3 eV. Both the decomposition temperature and activation energy for thermal decomposition were unaffected by the constituent phases of PtOx. Carrier to noise ratios (CNR) of over 40 dB for mark size of 150 nm were achieved in all super-resolution near-field structure (super-RENS) disks, while the super-resolution readout was limited to 2.5 × 103 ∼ 4.5 × 104 cycles. The effect of constituent phases of PtOx on the super-resolution capability of super-RENS disk with a PtOx mask layer was minimal. However, as the constituent phases of PtOx mask layer transformed from a mixture of Pt and PtO, to pure PtO, and then to a mixture of PtO and PtO2, the readout stability of super-RENS disk increased dramatically since less heat was absorbed by the PtOx mask layer composed of PtO and PtO2 during the readout process, prohibiting the diffusion of materials inside the bubble to the GeSbTe phase change layer.

Fire Retardant Cellulose Characterized by Thermal Degradation Behavior

2011 ◽  
Vol 197-198 ◽  
pp. 631-634
Author(s):  
Ming Gao ◽  
Yu Qing Yan
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Oxygen Index ◽  
Fire Retardant ◽  
Decomposition Temperature ◽  
Degradation Behavior ◽  
Limiting Oxygen Index ◽  
Thermal Degradation Behavior

Cellulose treated with fire retardant was studied by thermogravimetry (TG), differential thermal analysis (DTA) and limiting oxygen index (LOI). The kinetic parameters for the thermal degradation are obtained following the method of Broido. For the fire retardant cellulose, the activation energy and decomposition temperature were much decreased while char yield and LOI were increased. The main thermal decomposition of the samples with higher LOI occurs at lower temperatures, while that with lower LOI occurs at higher temperatures.

Application of Calculus Equation in Solving Thermal Decomposition Kinetics Parameters of Flame Retardant Wood

2014 ◽  
Vol 983 ◽  
pp. 190-193
Author(s):  
Cai Yun Sun ◽  
Yong Li Yang ◽  
Ming Gao
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Phosphoric Acid ◽  
Flame Retardant ◽  
Kinetic Parameters ◽  
Flame Retardancy ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Kinetics Parameters

Wood has been treated with amino resins and amino resins modified with phosphoric acid to impart flame retardancy. The thermal degradation of samples has been studied by thermogravimetry (TG) in air. From the resulting data, kinetic parameters for different stages of thermal degradation are obtained following the method of Broido. For the decomposition of wood and flame retardant wood, the activation energy is found to decrease from 122 to 72 kJmol-1.

Activation energy in the thermal decomposition of MgH2 powders by coupled TG–MS measurements

2013 ◽  
Vol 116 (2) ◽  
pp. 865-874 ◽  
Author(s):  
Renzo Campostrini ◽  
Mahmoud Abdellatief ◽  
Matteo Leoni ◽  
Paolo Scardi
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition

scholarly journals Structures and Properties of Self - crosslinking Silicone Resin

2018 ◽  
Vol 38 ◽  
pp. 02019
Author(s):  
Yong-xin Zhao ◽  
Ying-qiang Zhang
Keyword(s):  
Thermal Decomposition ◽  
Raw Materials ◽  
Decomposition Temperature ◽  
Light Transmittance ◽  
Silicone Resin ◽  
Structures And Properties ◽  
Vis Spectroscopy ◽  
Ft Ir ◽  
Good Heat Resistance ◽  
Good Heat

Highly transparent silicone resin with self-crosslinking structure was prepared using phenyltrimethoxysilane, diphenyldimethoxysilane, 1,3,5,7-cyclotetra(methyl siloxane) and bisvinyltetramethyldisiloxane as main raw materials. The structure of silicone resin was determined by Fourier Transform Infrared Spectroscopy (FT-IR). The light transmittance was measured by UV-Vis spectroscopy. Thermogravimetric analysis (TGA) was used to study the thermal decomposition process. The microstructure of cured self-crosslinking silicone resin is more uniform, resulting in better light transmittance up to 100% in the range of 400nm ~ 800nm. The cured has relatively good heat resistance, the initial thermal decomposition temperature of the cured could be up to 315.8 °C. SEM observations show that the self-crosslinking silicone has a uniform, textured structure, higher transparency compared with the existing condensation silicone material, and can be used as advanced architectural translucent materials and optics packaging materials.

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