Thermal decomposition of Y, La and lanthanide benzene-1,2-dioxyacetates in an air atmosphere

1996 ◽  
Vol 46 (6) ◽  
pp. 1687-1695
Author(s):  
W. Brzyska ◽  
A. Król
Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 195
Author(s):  
Ivan Vitázek ◽  
Martin Šotnar ◽  
Stella Hrehová ◽  
Kristína Darnadyová ◽  
Jan Mareček

The thermal decomposition of wood chips from an apple tree is studied in a static air atmosphere under isothermal conditions. Based on the thermogravimetric analysis, the values of the apparent activation energy and pre-exponential factor are 34 ± 3 kJ mol−1 and 391 ± 2 min−1, respectively. These results have also shown that this process can be described by the rate of the first-order chemical reaction. This reaction model is valid only for a temperature range of 250–290 °C, mainly due to the lignin decomposition. The obtained results are used for kinetic prediction, which is compared with the measurement. The results show that the reaction is slower at higher values of degree of conversion, which is caused by the influence of the experimental condition. Nevertheless, the obtained kinetic parameters could be used for the optimization of the combustion process of wood chips in small-scale biomass boilers.


2016 ◽  
Vol 30 (6) ◽  
pp. 5158-5166 ◽  
Author(s):  
Peng Chen ◽  
Lang Zhang ◽  
Kai Huang

2020 ◽  
Vol 85 (11) ◽  
pp. 1475-1488
Author(s):  
Lidija Radovanovic ◽  
Jelena Zdravkovic ◽  
Bojana Simovic ◽  
Zeljko Radovanovic ◽  
Katarina Mihajlovski ◽  
...  

Zinc oxide (ZnO) nanoparticles were obtained by thermal decomposition of one-dimensional zinc?benzenepolycarboxylato complexes as single- -source precursors at 450 ?C in an air atmosphere. The mechanism and kinetics of thermal degradation of zinc?benzenepolycarboxylato complexes were analyzed under non-isothermal conditions in an air atmosphere. The results of X-ray powder diffraction and field emission scanning electron microscopy revealed hexagonal wurtzite structure of ZnO with an average crystallite size in the range of 39?47 nm and similar morphology. The band gap and the specific surface area of ZnO nanoparticles were determined using UV?Vis diffuse reflectance spectroscopy and the Brunauer, Emmett and Teller method, respectively. The photoluminescent, photocatalytic and antimicrobial properties of the ZnO nanoparticles were also examined. The best photocatalytic activity in the degradation of C. I. Reactive Orange 16 dye was observed for the ZnO powder where the crystallites form the smallest agglomerates. All ZnO nanoparticles showed excellent inhibitory effect against Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Escherichia coli.


Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1591
Author(s):  
Jiuqiang Song ◽  
Zhixiong Huang ◽  
Yan Qin ◽  
Xinyi Li

The ceramifiable silicone rubber composite was prepared using hydrated zinc borate and kaolin as ceramifiable fillers. Effects of the hydrated zinc borate content and the combustion temperature on the properties of the ceramifiable silicone rubber composite were investigated. Thermal decomposition and ceramifying processes of the composite in a muffle furnace under air were also studied. The results showed that the density and the hardness of the composites increased as the content of the hydrated zinc borate increased from 0 to 30 phr. The tensile strength and elongation at break decreased. In addition, hydrated zinc borate decreased the decomposition temperature of the composite, whereas the residue weight under air atmosphere was increased. In the process of decomposition and oxidation of the ceramifiable silicone rubber composite in air, B2O3 was generated by the decomposition of zinc borate and participated in the formation of the residue network structure, which decreased the temperature of the ceramifying transition. The new phases, zinc aluminate (ZnO·Al2O3) and aluminum-rich mullite (9Al2O3·2SiO2), appeared after high-temperature thermochemical reactions. Microscopy images revealed that different structures were formed at different temperatures. The network structure of the ceramic residue became increasingly compact, and the compressive strength increased from 0.31 to 1.82 MPa with the increase of temperature from 800 to 1400 °C, which had a better protective effect on heat transfer and mass loss. The weight loss and the linear shrinkage of the ceramic residue was 37.6% and 21.9%, respectively, with the 30 phr content of hydrated zinc borate. The bending strength was improved from 0.11 to 11.58 MPa, and the compressive strength also increased from 0.03 to 1.14 MPa.


Biomaterials ◽  
1999 ◽  
Vol 20 (19) ◽  
pp. 1807-1813 ◽  
Author(s):  
Chun-Jen Liao ◽  
Feng-Huei Lin ◽  
Ko-Shao Chen ◽  
Jui-Sheng Sun

1999 ◽  
Vol 64 (10) ◽  
pp. 609-620 ◽  
Author(s):  
Pance Naumov ◽  
Gligor Jovanovski ◽  
Vera Jordanovska ◽  
Boyan Boyanov

In order to investigate the differences in the stability of the isomorphous pyridine saccharinates [Co(H2O)4(C5H5N)2](C7H4NO3S)2.4H2O and [Ni(H2O)4(C5H5N)2] (C7H4NO3S)2.4H2O, their thermal behavior (TG, DTG and DTAcurves) from ambient temperature up to 1000 ?C in a static air atmosphere was studied. For comparative purposes, the thermoanalytical curves of [Cu(H2O)(C5H5N)2(C7H4NO3S)2] were recorded as well. The decomposition pathways and the stability of the compounds are interpreted in the terms of the structural data. A possible mechanism for the decomposition of the saccharinato ion/ligand in an oxidizing atmosphere is proposed.The infrared spectral characteristics of the complexes are also discussed.


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