Nitrogen Isotope Separation by Means of Cation Exchange Resin, (I)

Abstract

In order to develop a feasible process for production of enriched 16N, nitrogen isotope separation by ion exchange has been studied. The attention has been placed on the concentration of the eluent LiOH solution introduced into the ion exchange column, packed with specially synthesized cation exchange resin. The ammonium ion adsorption band initially charged in the resin bed was eluted in a reverse breakthrough manner. The separation coefficients E have been confirmed not to be seriously affected by the eluent concentration. However a tendency of slight decrease in 5 has appeared in the high concentration region. The values of HETPs of the process have been also shown almost constant, in spite of the large difference in the migration velocity depending on the eluent concentration. The results suggest that the ion exchange rates are very fast a t high concentrations of the eluent, probably due to the large mobility of neutral ammonia in the resin.

Nitrogen Isotopic Reduced Partition Function Ratios of Glycine and Serine in Water

“…This nitrogen isotope preference can be understood through consideration based on an analogy with nitrogen isotope preference between ammonia and ammonium ion. Ion-exchange chromatographic nitrogen isotope separation that utilizes the nitrogen isotope exchange reaction between ammonia and ammonium ion is reported. − In the ion-exchange chromatographic process, the ion-exchange equilibrium is attained between ammonia in the solution phase and ammonium ion adsorbed on the cation-exchange site of a resin. The heavier isotope, 15 N, is preferentially absorbed on the resin, and consequently, that isotope is enriched in the end part of the ammonia band formed in the chromatographic column.…”