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  • Author: R. S. Lokhande x
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The radioactive isotopes 131I and 82Br were used to trace the ion-isotopic exchange reactions using industrial grade ion exchange resins Amberlite IRA-400. The experiments were performed to understand the effect of temperature and concentration of ionic solution on kinetics of exchange reactions. Both the exchange reactions were greatly influenced by rise in temperature, which result in higher percentage of ions exchanged. For bromide ion-isotopic exchange reactions, the calculated values of specific reaction rate/min-1, and amount of ions exchanged/mmol were obtained higher than that for iodide ion-isotopic exchange reactions under identical experimental conditions. The observed variation in the results for two ion-isotopic exchange reactions was due to the difference in the ionic size of bromide and iodide ions.

The radioactive 82Br was used as a tracer to study the bromide isotopic exchange reactions. The experiment was performed to study the effect of temperature, concentration of ionic solution, and amount of ion exchange resin on kinetics of isotopic exchange reactions. It was observed that under different experimental conditions, the amount of bromide ions exchanged and the initial rate of bromide ion exchange calculated for Duolite A 101D resins were higher than that for Duolite A 102D resins. It is expected that the same technique can be employed to assess the efficiency of various ion exchangers under different operating conditions. The probable mechanism of bromide isotopic exchange reaction was also predicted by comparing the specific reaction rate of rapid and slow exchange process.

The radioactive 131I was used as a tracer to study the kinetics of iodide ion-isotopic exchange reactions. The experiment was performed to study the effect of temperature, concentration of ionic solution, and amount of ion exchange resin on kinetics of exchange reactions. It was observed that under different experimental conditions, the initial rate and the amount of iodide ions exchanged calculated for Indion N-IP Type-2 resin were higher than that for Indion-830 Type-1 resins. It is expected that the same technique can be employed to assess the efficiency of various ion exchangers under different operating conditions.

Abstract

Elemental analysis of some medicinal plants used in the Indian Ayurvedic system was performed by employing instrumental neutron activation analysis (INAA) and atomic absorption spectroscopy (AAS) techniques. The samples were irradiated with thermal neutrons in a nuclear reactor and the induced activity was counted by gamma ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector. Most of the medicinal plants were found to be rich in one or more of the elements under study. The variation in elemental concentration in same medicinal plants samples collected in summer, winter and rainy seasons was studied and the biological effects of these elements on human beings are discussed.