Tracer Application in Study of Reaction Kinetics using Duolite ARA-9366B and Duolite A-638

Abstract

Radiotracer isotopes 131I and 82Br were used to study the iodide and bromide ion-isotopic exchange reactions taking place in two anion exchange resins Duolite ARA-9366B (nuclear grade) and Duolite A-638 (non-nuclear grade) under different operational parameters like temperature and ionic concentration of exchanging medium. The results of present investigation indicate an existence of strong positive linear co-relationship between amount of ions exchanged and concentration of ionic solution; while existence of strong negative co-relationship between amounts of ions exchanged and temperature of exchanging medium. It was observed that during iodide ion-isotopic exchange reaction under identical experimental conditions of 40.0 °C, 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 0.185, 0.417, 0.077 and 10.2 respectively for Duolite ARA-9366B resin, which was higher than 0.118, 0.338, 0.040 and 6.4 respectively for Duolite A-638 resins. It was observed that using Duolite ARA-9366B resins, at a constant temperature of 40.0 °C, as the concentration of labeled iodide ion solution increases from 0.001-0.004 M, the percentage of iodide ions exchanged increases from 51.70-57.5%. While using Duolite A-638 resins under identical experimental conditions, the percentage of iodide ions exchanged increases from 43.20-45.80%. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate superior performance of Duolite ARA-9366B resins over Duolite A-638 resins under identical operational parameters.
Keywords: Radiotracer isotopes, 131I; 82Br, non-destructive technique, ion-isotopic exchange reactions, radio analytical technique, anion exchange resins, nuclear grade resin, Duolite ARA-9366B, Duolite A-638