Characterization of polystyrene and polyacrylic based polymeric materials exposed to oxidative degradation

Kerntechnik ◽  
2021 ◽  
Vol 86 (4) ◽  
pp. 273-282
Author(s):  
P. U. Singare
Keyword(s):  
Thermodynamic Parameters ◽  
Thermodynamic Data ◽  
Reaction Rate ◽  
Isotopic Exchange ◽  
Oxidative Degradation ◽  
Polymeric Materials ◽  
Exchange Reactions ◽  
Degradation Medium ◽  
Kinetics And Thermodynamic

Abstract The characterization of oxidative degraded polystyrene-based resin (R1) and polyacrylic based resin (R2) resins in H2O2 and HClO4 degradation medium were made based on the kinetics and thermodynamic data obtained for the ion-isotopic exchange reactions using such resins. For the reactions performed by using resins degraded in H2O2 medium, the reaction rate (k) values obtained for the fresh R1 (0.315 min–1) and R2 (0.187 min–1) resins decreases to 0.300 and 0.155 min–1 respectively for the resins degraded in 20% H2O2 medium, which further decreases to 0.289 and 0.142 min–1 respectively for the resins degraded in 30% H2O2 medium. A similar trend in the results were observed for the reactions performed by using the above resins degraded in HClO4 medium. The higher values of k (min–1) and low values of various thermodynamic parameters for the ion-isotopic exchange reactions performed by using fresh and degraded polystyrene-based resin R1 resins suggests superior degradation stability as compared to polyacrylic based R2 resin.

scholarly journals Isotope exchange reactions involving HCO+ with CO: A theoretical approach

2017 ◽  
Vol 605 ◽  
pp. A22 ◽  
Author(s):  
M. Mladenović ◽  
E. Roueff
Keyword(s):  
Reaction Rate ◽  
Isotopic Exchange ◽  
Least Squares Method ◽  
Outer Space ◽  
Nonlinear Least Squares ◽  
Rate Coefficients ◽  
Exchange Reactions ◽  
Forward Reaction ◽  
Equilibrium Conditions ◽  
Nonlinear Least Squares Method

Aims. We aim to investigate fractionation reactions involved in the 12C/13C, 16O/18O, and 17O balance. Methods. Full-dimensional rovibrational calculations were used to compute numerically exact rovibrational energies and thermal equilibrium conditions to derive the reaction rate coefficients. A nonlinear least-squares method was employed to represent the rate coefficients by analytic functions. Results. New exothermicities are derived for 30 isotopic exchange reactions of HCO+ with CO. For each of the reactions, we provide the analytic three-parameter Arrhenius-Kooij formula for both the forward reaction and backward reaction rate coefficients, that can further be used in astrochemical kinetic models. Rotational constants derived here for the 17O containing forms of HCO+ may assist detection of these cations in outer space.

scholarly journals Comparative Study of Anion Exchange Resins Purolite NRW-6000 and Duolite A-143 by Application Isotopic Technique

2013 ◽  
Vol 17 ◽  
pp. 1-13
Author(s):  
P.U. Singare
Keyword(s):  
Reaction Rate ◽  
Isotopic Exchange ◽  
Tracer Technique ◽  
Exchange Reactions ◽  
Specific Reaction Rate ◽  
Experimental Conditions ◽  
Anion Exchange Resins ◽  
Isotopic Exchange Reaction ◽  
Bromide Ion ◽  
Exchange Resins

Isotopic tracer technique using 131I and 82Br was used to characterize Purolite NRW-6000 and Duolite A-143 anion exchange resins. The characterization study was done by carrying out iodide and bromide ion-isotopic exchange reactions taking place between the resin surface and the external labeled ionic solution. For the two resins it was observed that under identical experimental conditions, the values of specific reaction rate (min-1), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) were calculated to be lower for bromide ion-isotopic exchange reaction than that for iodide ion-isotopic exchange reaction. Also during both the ion-isotopic exchange reactions, under identical experimental conditions for the two resins, the values of specific reaction rate increases with increase in ionic concentration and was observed to decrease with rise in temperature. For a constant temperature of 35.0 °C, as the concentration of labeled bromide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of bromide ions exchanged increases from 67.80% to 72.76% using Purolite NRW-6000 resin and from 42.54% to 50.45% using Duolite A-143 resin. However when the temperature was raised from 30.0 °C to 45.0 °C by keeping the concentration of labeled bromide ion solution constant at 0.002 mol/L, the percentage of bromide ions exchanged decreases from 70.68 % to 67.32 % using Purolite NRW-6000 resin and from 47.50% to 42.25% using Duolite A-143 resin. From the results it appears that Purolite NRW-6000 resins show superior performance over Duolite A-143 resins under identical experimental conditions. It is expected that the present isotopic tracer technique can be applied further as an efficient nondestructive technique in characterization of various ion exchange resins so as to bring about their efficient industrial applications.

scholarly journals Are rate and selectivity correlated in iridium-catalysed hydrogen isotope exchange reactions?

2021 ◽  
Author(s):  
Daria S. Timofeeva ◽  
David M Lindsay ◽  
W. J. Kerr ◽  
David James Nelson
Keyword(s):  
Functional Groups ◽  
Hydrogen Isotope ◽  
Isotope Exchange ◽  
Reaction Rate ◽  
Exchange Reactions ◽  
Reaction Selectivity ◽  
Hydrogen Isotope Exchange ◽  
The Relationship

Herein we examine the relationship between reaction rate and reaction selectivity in iridium-catalysed hydrogen isotope exchange (HIE) reactions directed by Lewis basic functional groups. We have recently develped a directing...

Adsorption of Ni (II) from Aqueous Solution Based on Porous Magnetic/Chitosan Resin

2014 ◽  
Vol 936 ◽  
pp. 829-833
Author(s):  
Hai Song ◽  
Xing Hai Yu ◽  
Xiao Qin Zhang ◽  
Gui Fang Yan ◽  
Yuan Zhi Zhen
Keyword(s):  
Aqueous Solution ◽  
Aqueous Medium ◽  
Thermodynamic Parameters ◽  
Adsorption Process ◽  
Low Cost ◽  
Second Order ◽  
Magnetic Chitosan ◽  
Spontaneous Process ◽  
Chitosan Resin ◽  
Kinetics And Thermodynamic

The purpose of this work is to prepare a low-cost biosorbent,Porous Magnetic/Chitosan Resin(MCR), and determine the ability of this biosorbent to removing Ni (II) ion from aqueous medium. Both kinetics and thermodynamic parameters of the adsorption process were also estimated. The thermodynamic parameters indicated an exothermic spontaneous process and the kinetics followed the second-order adsorption process.

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