ENRICHMENT OF ZINC ISOTOPES BY A LIQUID MEMBRANE SYSTEM USING A CROWN-ETHER

Citation
K. Nishizawa et al., ENRICHMENT OF ZINC ISOTOPES BY A LIQUID MEMBRANE SYSTEM USING A CROWN-ETHER, Separation science and technology, 33(7), 1998, pp. 991-1002
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Engineering, Chemical",Chemistry
ISSN journal
0149-6395
Volume
33
Issue
7
Year of publication
1998
Pages
991 - 1002
Database
ISI
SICI code
0149-6395(1998)33:7<991:EOZIBA>2.0.ZU;2-F
Abstract
A liquid membrane system to enrich zinc isotope was investigated. The liquid membrane was composed of a solution of dicyclohexano-18-crown-6 in chloroform. Zinc chloride dissolved in diluted hydrochloric acid w as used as a feed phase. A receiving phase was made of a 0.001 M HCl s olution. The zinc isotopes were enriched (1) at the interface of the l iquid-membrane/feed-phase and (2) at that of the liquid-membrane/recei ving-phase. The separation factor attained in the system was alpha = 1 .049 for the separation of Zn-64 and Zn-66. The enrichment factor of Z n-66 relative to Zn-67 was epsilon = -0.053, which is in the inverse d irection of enrichment by a liquid-liquid extraction. The enrichment f actor of Zn-64 to Zn-66 showed a different value from that of Zn-66 to Zn-68, regardless of their similar mass difference. The isotope effec ts in the Zn-crown complex were dominated by the field shift of electr onic energy in the isotope atom, This is in contrast to the Bigeleisen -Mayer approximation for a chemical exchange reaction.