scholarly journals Investigation of Kinetic and Thermodynamic Parameters Approaches to Non-isothermal Pyrolysis of Mustard Stalk Using Model-Free and Master Plots Methods

Author(s):  
Kalpana Patidar ◽  
Ajit Singathia ◽  
Manish Vashishtha ◽  
Vikas Kumar Sangal ◽  
Sushant Upadhyaya
2020 ◽  
Vol 3 ◽  
pp. 173-181
Author(s):  
Jingchong Yan ◽  
Qitong Yang ◽  
Li Zhang ◽  
Zhiping Lei ◽  
Zhanku Li ◽  
...  

2019 ◽  
Vol 38 (2) ◽  
pp. 202-212 ◽  
Author(s):  
Ghulam Ali ◽  
Jan Nisar ◽  
Munawar Iqbal ◽  
Afzal Shah ◽  
Mazhar Abbas ◽  
...  

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin−1, 10°Cmin−1, 15°Cmin−1 and 20°Cmin−1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats–Redfern) and model free methods (Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats–Redfern, Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman models were found in the ranges 105–148.48 kJmol−1, 99.41–140.52 kJmol−1, 103.67–149.15 kJmol−1 and 99.93–141.25 kJmol−1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.


1983 ◽  
Vol 18 (2) ◽  
pp. 117-124 ◽  
Author(s):  
Eraldo Antonini ◽  
Maurizio Brunori ◽  
Alfredo Colosimo ◽  
Harm A. Kuiper ◽  
Lello Zolla

2017 ◽  
Vol 9 (4) ◽  
pp. 17
Author(s):  
Jean B. Fagbohoun ◽  
Mankambou J. Gnanwa ◽  
Fankroma M. T. Kone ◽  
S. Dabonne ◽  
Patrice L. Kouame

Optimization of thermal processes relies on adequate degradation kinetic models to warrant food safety and quality. The knowledge on thermal inactivation of enzymes is necessary to allow their proper utilization in food industry and technology applications, enabling the reduction of heating times and optimization of heating temperatures. In this work, the kinetic of thermal inactivation was studied for the previously characterized carboxylmethylcellulases Ab-CX1 and Ab-CX2 from Macrotermes subhyalinus little soldier. Samples of carboxymethylcellulases were treated at different time-temperature combinations in the range of 5-60 min at 50-65°C and the kinetic and thermodynamic parameters for carboxymethylcellulases were calculated. Results showed that inactivation followed a first-order reaction with k-values between 0.0103 ± 0.0003 to 0.1217 ± 0.0005 and 0.0149 ± 0.0007 to 0.0416 ± 0.0003 min-1 for Ab-CX1 and Ab-CX2, respectively. At high temperatures, Ab-CX2 was less resistant, with a significant decrease in residual activity compared to Ab-CX1. The D- and k-values decreased and increased, respectively, with increasing temperature, indicating faster inactivation of carboxymethylcellulases. Activation energy (Ea) and Z-values were estimated to 76.74 ± 1.98 kJ.mol-1 and 24.21 ± 1.92 °C for Ab-CX1, 62.80 ± 2.05 kJ.mol-1 and 33.33 ± 2.78 °C for Ab-CX2. Thermodynamic parameters (ΔH#, ΔS# and ΔG#) were also calculated. The high value obtained for the variation in enthalpy of activation indicates that a high amount of energy is required to initiate denaturation, probably due to the molecular conformation of carboxymethylcellulases. All results suggest that both carboxymethylcellulases are relatively resistant to long heat treatments up to 50°C.


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