CHIMERA: A software tool for reaction rate calculations and kinetics and thermodynamics analysis

2002 ◽  
Vol 23 (14) ◽  
pp. 1375-1389 ◽  
Author(s):  
Konstantin P. Novoselov ◽  
Denis B. Shirabaikin ◽  
Stanislav Ya. Umanskii ◽  
Alexander S. Vladimirov ◽  
Airat Kh. Minushev ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Software Tool ◽  
Kinetics And Thermodynamics ◽  
Thermodynamics Analysis

Photocatalytic Degradation of Methyl Orange by TiO2/Schorl Photocatalyst: Kinetics and Thermodynamics

2015 ◽  
Vol 713-715 ◽  
pp. 2789-2792
Author(s):  
Huan Yan Xu ◽  
Xue Li ◽  
Yan Li ◽  
Ping Li ◽  
Wei Chao Liu
Keyword(s):  
Methyl Orange ◽  
Reaction Rate ◽  
Reaction Kinetic ◽  
Kinetic Studies ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Solution Ph ◽  
Kinetics And Thermodynamics ◽  
Hoff Equation ◽  
Degradation Of Methyl Orange

An active dye, Methyl Orange (MO) was employed as the target pollutant to evaluate the photocatalytic activity of TiO2/schorl composite and the kinetics and thermodynamics of this process was emphasized in this work. Langmuir–Hinshelwood kinetic model was employed for the kinetic studies and the results revealed that the process of MO photocatalytic discoloration by TiO2/schorl composite followed one order reaction kinetic equation under different conditions. The reaction rate constant (k) increased with initial MO concentration decreasing. When the catalyst dosage or solution pH increased,kvalues increased and then decreased. The possible reasons for these phenomena were discussed. Finally, the thermodynamic parameters ΔG, ΔH, ΔSwere obtained by the classical Van't Hoff equation.

scholarly journals Kinetics and Thermodynamics Study of Ultrasound-Assisted Depolymerization of k-Carrageenan in Acidic Solution

2020 ◽  
Vol 15 (1) ◽  
pp. 280-289
Author(s):  
Ratnawati Ratnawati ◽  
Nita Indriyani
Keyword(s):  
Molecular Weight ◽  
Rate Constant ◽  
Reaction Rate ◽  
Acidic Solution ◽  
Biomedical Application ◽  
Bond Cleavage ◽  
Reaction Rate Constant ◽  
Order Kinetic ◽  
Kinetics And Thermodynamics ◽  
Ultrasound Assisted

K-carrageenan is a natural polymer with high molecular weight ranging from 100 to 1000 kDa. The oligocarrageenan with low molecular weight is widely used in biomedical application. The aim of this work was to depolymerize k-carrageenan in an acidic solution with the assistance of ultrasound irradiation. The ultrasonication was conducted at various pH (3 and 6), temperatures (30-60 °C), and depolymerization time (0-24 minutes). The results show that the depolymerization reaction follows pseudo-first-order kinetic model with reaction rate constant of 1.856×10-7 to 2.138×10-6 s-1. The reaction rate constant increases at higher temperature and lower pH. The Q10-temperature coefficients of the depolymerization are 1.25 and 1.51 for pH 6 and 3, respectively. The enthalpy of activation (ΔH‡) and the Gibbs energy of activation (ΔG‡) are positive, while the entropy of activation (ΔS‡) is negative, indicating that the activation step of the ultrasound-assisted depolymerization of k-carrageenan is endothermic, non-spontaneous, and the molecules at the transition state is more ordered than at the ground state. The ΔH‡ and the ΔS‡ are not affected by temperature, while the ΔG‡ is a weak function of temperature. The ΔH‡ and ΔS‡ become smaller at higher pH, while the ΔG‡ increases with the increase of pH. The kinetics and thermodynamics analysis show that the ultrasound-assisted depolymerization of k-carrageenan in acidic solution is possibly through three mechanisms, i.e. bond cleavage due to cavitational effect of microbubbles, hydroxyl radical and hydrogen peroxide, as well as proton. Copyright © 2020 BCREC Group. All rights reserved 

scholarly journals APUAMA: a software tool for reaction rate calculations

2017 ◽  
Vol 23 (6) ◽  
Author(s):  
Henrique O. Euclides ◽  
Patricia R. P. Barreto
Keyword(s):  
Reaction Rate ◽  
Software Tool

Kinetics and Thermodynamics Study of Thiosulfate Removal from Water by Calcined MgAl-CO3 Layered Double Hydroxides

2011 ◽  
Vol 396-398 ◽  
pp. 880-885
Author(s):  
Cui Yu Geng ◽  
Xiao Yu ◽  
Zheng Chang ◽  
Xiao Dong Lei ◽  
Xiao Ming Sun ◽  
...  
Keyword(s):  
Memory Effect ◽  
Layered Double Hydroxides ◽  
Reaction Rate ◽  
Langmuir Equation ◽  
Contaminated Water ◽  
Equilibrium Isotherm ◽  
Kinetics And Thermodynamics ◽  
Pseudo Second Order ◽  
Uptake Process ◽  
Double Hydroxides

Layered double hydroxides (LDHs) are potential scavengers for anionic contaminants due to their “memory effect”. Here we report the removal of thiosulfate anion from contaminated water by calcined MgAl–CO3 LDH (CLDH). The results indicate that CLDH exhibits a good performance in adsorption of thiosulfate.We studied the kinetics and thermodynamics of adsorption of thiosulfate from water. The equilibrium isotherm showed that the uptake of thiosulfate anion well agrees with the Langmuir equation, the positive value of △HӨ demonstrates the endothermic feature of the adsorption, the pseudo-second order kinetics model can be uItalic textsed to describe the uptake process and the value of Ea was calculated to be 75.898 kJ/mol. Our results suggest that the process of thiosulfate uptaking was controlled by the reaction rate of thiosulfate with the CLDH rather than diffusion.

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