scholarly journals Thermodynamics of Ion-Exchange Reaction in Predicting the Ionic Selectivity of Auchlite ARA-9366 and Auchlite A-378 Anion Exchange Resins

Author(s):  
P.U. Singare ◽  
A.N. Patange

The paper deals with predicting the iodide ion selectivity of nuclear and non-nuclear grade anion exchange resins. The ionic selectivity prediction was made on the basis of thermodynamic data of Clˉ/I ˉ ion exchange reaction. It was observed that with rise in temperature from 30.0°C to 45.0 °C, the equilibrium constant (K) values were observed to decreases from 59.77x10-2 to 23.77x10-2 for Auchlite ARA-9366 resins and from 9.01x10-2 to 4.05x10-2 for Auchlite A-378 resins. The decrease in K values with rise in temperature, indicate exothermic ion exchange reactions having enthalpy values of -47.87 and -39.51 kJ/mol respectively. The high K and low enthalpy values obtained for Auchlite ARA-9366 resins indicate their greater selectivity for the iodide ions in the solution as compared to Auchlite A-378 resins, when both the resins are present in chloride form.

Author(s):  
P.U. Singare ◽  
A.N. Patange

In the present investigation, attempts were made to understand the difference in bromide ion selectivity of the two closely related anion exchange resins Auchlite ARA-9366 and Auchlite A-378 in chloride form. The selectivity difference was predicted based on the thermodynamic equilibrium constants and enthalpy values of Clˉ/Brˉ ion exchange reactions performed by using the two resins. During Clˉ/Brˉ exchange reactions, with rise in temperature from 30.0°C to 45.0 °C, the equilibrium constant (K) values were observed to decreases from 8.15x10-2 to 6.06x10-2 for Auchlite ARA-9366 resins and from 2.16x10-2 to 1.10x10-2 for Auchlite A-378 resins. The decrease in K values with rise in temperature, indicate exothermic ion exchange reactions having enthalpy values of -36.14 and -18.38 kJ/mol respectively. The high K and low enthalpy values obtained for Auchlite ARA-9366 resins indicate their greater selectivity for the bromide ions in the solution as compared to Auchlite A-378 resins.


Author(s):  
P.U. Singare

The present paper demonstrates application of isotopic tracer technique in characterization of anion exchange resins Dowex-SBR LC and Indion-454 for which 131I and 82Br radio isotopes were used. The characterization was made based on iodide and bromide ion-isotopic exchange reaction kinetic data obtained for the two resins. It was observed that during iodide ion-isotopic exchange reaction performed at 35.0 °C, 1.000 g of ion exchange resins and 0.002 mol/L labeled iodide ion solution, the values of specific reaction rate (min-1), amount of ion exchanged (mmol), initial rate of ion exchange (mmol/min) and log Kd were 0.379, 0.426, 0.161 and 16.2 respectively for Dowex-SBR LC resin, which was higher than the respective values of 0.156, 0.243, 0.038 and 13.4 as that obtained by using Indion-454 resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The results of present investigation also indicate that during the two ion-isotopic exchange reactions, for both the resins, there exists a strong positive linear correlation between amount of ions exchanged and concentration of ionic solution; and strong negative correlation between amount of ions exchanged and temperature of exchanging medium. Based on overall results it appears that under identical experimental conditions, as compared to Indion-454 resins, Dowex-SBR LC resins show superior performance. It is expected here that the present technique can be extended further for characterization of different ion exchange resins which will further help in the selection of those reins for the specific industrial application


Author(s):  
P.U. Singare ◽  
A.N. Patange

The thermodynamic approach was applied to predict the trend selectivity of industrial grade anion exchange resin Auchlite A-378 in chloride form towards iodide and bromide ions in the solution. The study was conducted by performing the Clˉ/Iˉ and Clˉ/Brˉ uni-univalent ion exchange reactions under gradually increasing temperature conditions. The thermodynamic equilibrium constants K values were used to calculate the enthalpies of the two uni-univalent ion exchange reactions. It was observed that the K values for Clˉ/Iˉ ion exchange reaction were higher than Clˉ/Brˉ exchange reaction under identical experimental conditions. Also the enthalpy values for the two uni-univalent ion exchange reactions were calculated as -39.51 and -18.38 kJ/mol respectively. The high K and low enthalpy values obtained for Clˉ/Iˉ ion exchange reaction is responsible for higher selectivity of the resin towards iodide ions as compared to that towards bromide ions, when both the ions are present in the same solution.


Author(s):  
P.U. Singare

Radio analytical technique as a non-destructive technique was used in the present investigation to trace the kinetics of ion-isotopic exchange reaction taking place in Duolite ARA-9366 (nuclear grade) and Duolite A-171 (non-nuclear grade) anion exchange resins. The kinetics data suggest that during iodide ion-isotopic exchange reactions under identical experimental conditions of 40.00C, 1.000 g of ion exchange resins and 0.003 M labeled iodide ion solution, the values of specific reaction rate (min-1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were 0.176, 0.383, 0.067 and 7.8 respectively for Duolite ARA-9366 resin, which was higher than 0.142, 0.353, 0.050 and 7.0 respectively as that obtained for Duolite A-171 resins. Also it is observed that at a constant temperature of 40.0 °C, as the concentration of labeled iodide ion solution increases 0.001 M to 0.004 M, the percentage of iodide ions exchanged increases from 49.20% to 51.80% for Duolite ARA-9366 resins; and from 45.20% to 47.80% for Duolite A-171 resins. The similar trend was observed for the two resins during bromide ion-isotopic exchange reactions. The overall results indicate superior performance of Duolite ARA-9366 resins over Duolite A-171 resins under identical operational parameters.


Author(s):  
P.U. Singare ◽  
A.N. Patange

The selectivity behaviour of nuclear grade anion exchange resin Auchlite ARA-9366 in chloride form towards iodide and bromide ions in the solution was studied. The trend in selectivity of the resin was predicted on the basis of thermodynamics of Clˉ/Iˉ and Clˉ/Brˉ uni-univalent ion exchange reactions. It was observed that the equilibrium constants K values for Clˉ/Iˉ ion exchange reaction were higher than that calculated for Clˉ/Brˉ exchange under identical experimental conditions. Also the enthalpy values for the two uni-univalent ion exchange reactions were calculated as -47.87 and -36.14 kJ/mol respectively. The high K and low enthalpy values obtained for Clˉ/Iˉ ion exchange reaction as compared to that obtained during Clˉ/Brˉ exchange supports higher selectivity of the resin towards iodide ions as compared to that towards bromide ions, when both the ions are present in the same solution.


CrystEngComm ◽  
2015 ◽  
Vol 17 (45) ◽  
pp. 8703-8709 ◽  
Author(s):  
Yingqi Wang ◽  
Xiaofang Lai ◽  
Xujie Lü ◽  
Yanting Li ◽  
Qinglong Liu ◽  
...  

The photocatalytic activity of the layered perovskite K2La2Ti3O10 was regulated by an ion-exchange reaction with a series of cations – Ca2+, Sr2+, and Ba2+. The underlying mechanism of the improved performance and an effective model for designing the photocatalyst were discussed.


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