A STUDY OF COMPLEXES YIELDED BY HNO3Fe(III)AND Eu(III) EXTRACTION FROM NITRATE MEDIA WITH ACIDIC Zr(IV) AND Hf( IV) DI-2-ETHILHEXYLPHOSPHATES
作者:
E.S. Stoyanov,
V.A. Mikhailov,
O.M. Petrukhin,
V. Shipulo,
G.A. Yagodin,
期刊:
Solvent Extraction and Ion Exchange
(Taylor Available online 1991)
卷期:
Volume 9,
issue 5
页码: 787-831
ISSN:0736-6299
年代: 1991
DOI:10.1080/07366299108918085
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Possible reasons for significant enhancement of solvent extraction of some metals with dialkylphos-phoric acids in the presence of Zr(IV) and Hf(IV) are critically discussed, taking into consideration both the literature and the autors'data on the structure of acidic salts formed by these acids with Zr(IV) and Hf(IV). The chemistry of extraction of nitric acid, FeUII) and Eu ( I I I ) with Zr(IV) and Hf(IV) salts of di-2-ethy1hexy1 phosphoric acid (HX) has been studied using IR and31P NMR spectroscopy. Nitric acid is extracted by these salts due to interaction with their acceptor sites that results in the formation of a new polymeric extractant with bidentate anions of two types, (X-H-X)- and (X-H-N03)_. Protons of these groups can be exchanged with metal cations extracted, e.g., with Fe(III) or Eu(I 11 ), heteropolynuc1 ear complexes with non-equivalent (chelating and bridge) N03anions being formed during the extraction. The composition and structure of coordination polyhedrons formed around Zr(IV), Hf(IV), Fe(III) and Eu(III) have been determined. The reasons for a higher extraction ability of the salts studied for Fe(III) and Eu(III) versus D2EHPA itselfaredescribed.
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