Published March 1962 | Version v1
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Ion exchange studies of alpha-hydroxy carboxylic acid-lanthanide and actinide systems

Creators

  • 1. Florida State University, Tallahassee, FL (United States)
  • 2. Research Institute of National Defence, Dept. 4, Stockholm (Sweden)

Description

Alpha-hydroxy carboxylic acids have been used extensively for the separation of lanthanide and actinide elements with cation exchange resins. Sorption of these elements in the same solutions occurs on strong base anion-exchange resins. A study has been made by elution and equilibrium distribution techniques of the behaviour at tracer-level concentrations of these anion-exchange systems. One objective was to measure the separation factors to assess anion exchange as a possible complement to cation exchange separation. Since very little attention has been given to characterizing the complexed species present in these separation systems, a second objective was to attempt such characterization through interpretation of both cation and anion exchange data. Glycolic, lactic and alpha-hydroxy isobutyric acids were used together with radioactive tracers of Ce, Pm, Eu, Tb, Tm, Y, Cm and Cf. The elutions and equilibrium distributions were performed both at 25o C and 87o C. In all three eluants, the separation factors were smaller for the anion exchange than for the analogous cation exchange. In the glycolate solutions, the separation factors were largest and the values of the distribution coefficient Kd. indicated that these were the most stable complexes. The plots of log Kd against log anion concentration pass through a maximum and then approach a slope of -1, indicating the presence of an anionic complex MX4-. The existence of this negative complex in the solution phase was demonstrated by electromigration studies of Tm170 tracer in these solutions. At the solution concentration corresponding to the maximum Kd value, it can be shown that the predominant solution species is MX3. Approximate successive stability constants have been calculated for these systems and with these it is possible to construct diagrams showing the relative concentration of the species M+3, MX+2, MX2+, MX3 and MX4- as a function of the concentration of X-. (author)

Abstract (French)

Les acides α-hydroxycarboxyliques sont souvent utilises pour la separation des lanthanides et des actinides au moyen de resines echangeuses de cations. La sorption de ces elements dans les memes solutions peut etre realisee avec des resines echangeuses d'anions fortement basiques. Les auteurs ont etudie les proprietes de ces systemes d'echange d'anions, a des concentrations extremement faibles, en employant des techniques d'elution et des techniques fondees sur la distribution d'equilibre. L'un des buts recherches etait de mesurer les facteurs de separation pour voir dans quelle mesure l'echange d'anions peut completer la separation par echange de cations. Etant donne qu'on ne s'est guere preoccupe jusqu'a present de caracteriser les especes chimiques qui apparaissent sous forme de complexes dans ces systemes de separation, les auteurs se sont efforces de le faire - et c'etait la leur deuxieme objectif - en interpretant les resultats des essais d'echange de cations et d'anions. Les auteurs ont utilise les acides glycolique, lactique et α-hydroxy-isobutyrique avec divers indicateurs radioactifs : cerium, prometheum, europium, terbium, thulium, yttrium, curium et californium. L'elut ion et la distribution d'equilibre ont ete realisees a 25oC et a 87oC. Avec chacun des trois eluants, les facteurs de separation sont plus faibles pour l'echange d'anions que pour l'echange analogue de cations. Ils sont a leur maximum avec les glycolates, et les valeurs du coefficient de distribution Kd montrent que les glycolates sont les complexes les plus stables. Les courbes du log Kd en fonction du logarithme de la concentration d'anions passent par un maximum, puis ont une pente tendant vers -1, ce qui denote la presence d'un complexe anionique du type MX4-. L'existence de ce complexe negatif dans la solution a ete demontree par l'etude electromigratoire de l'indicateur thulium-170. Pour une concentration de la solution, correspondant a la valeur maximum de Kd, on peut demontrer que l'espece chimique qui predomine dans la solution du type est MX3. Les auteurs ont calcule approximativement les constantes successives de stabilite correspondant a ces systemes; ces constantes permettent de tracer les courbes des concentrations relatives des especes chimiques M3+, MX2+, MX2+, MX3 et MX4- en fonction de la concentration de X-. (author)

Abstract (Spanish)

Los acidos alfa-hidroxicarboxilicos se utilizan extensamente para separar elementos lantanidos y actinidos con ayuda de resinas intercambiadoras de cationes. La sorcion de estos elementos puede efectuarse con resinas intercambiadoras de aniones de caracter fuertemente basico. Los autores han estudiado las propiedades de estos sistemas de intercambio de aniones a concentraciones extremadamente bajas, empleando tecnicas de elucion y de estudio de los equilibrios de distribucion. Una de las finalidades perseguidas era medir los factores de separacion para poder evaluar en que medida el intercambio de aniones puede utilizarse como complemento de la separacion por intercambio cationico. Puesto que se ha dedicado poca atencion a la caracterizacion de las especies quimicas que aparecen en forma de complejos en estos sistemas de separacion, la segunda finalidad de los trabajos realizados por los autores fue tratar de caracterizarlos interpretando los resultados de los ensayos de intercambio anionico y cationico. Los autores han empleado acidos glicolico, lactico y α-hidroxiisobutirico con Ce, Pm, Eu, Tb, Tm, Y, Cm y Cf como trazadores radiactivos. Tanto la elucion como la distribucion de equilibrio se llevaron a cabo a 25o C y 87o C. En los tres casos, los factores de separacion son menores para el intercambio de aniones que para el intercambio analogo de cationes. Los mayores factores de separacion se obtienen con glicolatos, y los valores del coeficiente de distribucion Kd indican que dichos glicolatos constituyen los complejos mas estables. Las curvas de log Kd en funcion del logaritmo de la concentracion anionica pasan por un maximo y luego su pendiente tiende a -1, lo cual indica la presencia de un complejo anionico del tipo MX4-. El estudio electromigratorio del trazador 170Tm en estas soluciones confirma la existencia de este complejo negativo en la solucion. Se puede demostrar que a la concentracion correspondiente al valor maximo de Kd la especie quimica que predomina en la solucion pertenece al tipo MX3. Los autores han calculado los valores aproximados de las sucesivas constantes de estabilidad correspondientes a estos sistemas, y dichos valores les han permitido trazar curvas de las concentraciones relativas de las especies quimicas M3+, MX2+, MX2+, MX3 y MX4 en funcion de la concentracion de X-. (author)

Abstract (Russian)

Al'fa-gidro-oksikarbolovye kisloty byli shiroko ispol'zovany dlya otdeleniya ehlementov gruppy lantanidov i aktinidov pri pomoshchi smol s kationnym obmenom. Sorbtsiya ehtikh ehlementov v odnikh i tekh zhe rastvorakh proiskhodit na smolakh anionnogo obmena s sil'nym osnovaniem. Metodami vymyvaniya i uravnoveshennogo raspredeleniya byli izucheny protsessy, proiskhodyashchie v ehtikh sistemakh anionnogo obmena v nichtozhnykh kontsentratsiyakh. Odnoj iz tselej bylo izmerenie faktorov otdeleniya dlya otsenki anionnogo obmena v kachestve vozmozhnogo dopolneniya k otdeleniyu kationnym obmenom. Tak kak do sikh por udelyalos' ochen' malo vnimaniya opoznavaniyu slozhnykh soedinenij, imeyushchikhsya v ehtikh sistemakh otdeleniya, vtoroj tsel'yu bylo popytat'sya opoznat' ehti soedineniya putem tolkovaniya dannykh kak kationnogo, tak i anionnogo obmenov. Byli ispol'zovany glikojnaya, molochnaya i al'fa-oksi-izomasyanaya kisloty vmeste s izotopami tseriya (Ce), prometiya (Pm), evropiya (Eu), terbiya (Tb), tuliya (Tu), ittriya (Y), kyuriya (Cm) i kaliforniya (Cf) v kachestve indikatorov. Vymyvanie i uravnoveshennoe raspredelenie proizvodilis' pri temperaturakh 25o C i 87o C. Vo vsekh ehtikh trekh ehlyuentakh faktory otdeleniya byli men'shimi dlya anionnogo obmena, chem dlya analogichnogo kationnogo obmena. V rastvorakh glikolatov faktory otdeleniya byli naivysshimi i znacheniya koehffitsienta raspredeleniya Kd ukazyvayut, chto ehti slozhnye soedineniya yavlyayutsya naibolee ustojchivymi. Krivaya log Kd v zavisimosti ot logarifma anionnoj kontsentratsii prokhodit cherez maksimum, zatem priblizhaetsya k naklonu v - 1, ukazyvaya na nalichie anionnogo kompleksa MX4-. Nalichie ehtogo otritsatel'nogo slozhnogo soedineniya v faze rastvora bylo dokazano pri pomoshchi ehlektromigratsionnogo izucheniya povedeniya indikatora iz tuliya-170 v ehtikh rastvorakh. Mozhno dokazat', chto pri kontsentratsii rastvora, sootvetstvuyushchej maksimal'nomu znacheniyu Kd, preobladayushchim veshchestvom v rastvore yavlyaetsya MX3. Dlya ehtikh sistem byli podschitany priblizitel'nye posledovatel'nye konstanty ustojchivosti i blagodarya ehtim konstantam predstavlyaetsya vozmozhnym postroit' krivye, dayushchie otnositel'nuyu kontsentratsiyu grupp M+3, MX+2, MX2+, MK3 i MX4 v funktsii ot kontsentratsii X-. (author)
Part of:
Radioisotopes in the Physical Sciences and Industry. Proceedings of the Conference on the Use of Radioisotopes in the Physical Sciences and Industry. V. III

Additional details

Additional titles

Original title (English)
Etudes, par echange d'ions, sur des systemes de sels de lanthanidcs et d'actinides des acides alpha-hydroxycarboxyliques; Izuchenie ionnogo obmena sistem al'fa-gidro-oksikarbolovoj kisloty i lantanidov ili aktinidov; Estudios de intercambio ionico en los sistemas de sales de lantanidos y actinidos de los acidos alfa-hidroxicarboxilicos

Publishing Information

Publisher
Globus, Druck- und Verlagsanstalt
Imprint Place
Vienna (International Atomic Energy Agency (IAEA))
Imprint Title
Radioisotopes in the Physical Sciences and Industry. Proceedings of the Conference on the Use of Radioisotopes in the Physical Sciences and Industry. V. III
Imprint Pagination
652 p.
Series
Proceedings Series
Journal Page Range
p. 282-299
ISSN
0074-1884

Conference

Title
Conference on the Use of Radioisotopes in the Physical Sciences and Industry
Dates
6-17 Sep 1960
Place
Copenhagen (Denmark)

INIS

Country of Publication
International Atomic Energy Agency (IAEA)
Country of Input or Organization
International Atomic Energy Agency (IAEA)
INIS RN
43113024
Subject category
S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; S07: ISOTOPES AND RADIATION SOURCES;
Resource subtype / Literary indicator
Conference
Descriptors DEI
ANIONS; CATIONS; COMPLEXES; DISTRIBUTION; ELECTROPHORESIS; ION EXCHANGE; ISOBUTYRIC ACID; RARE EARTHS; RESINS; SOLUTIONS; SORPTION; STABILITY; THULIUM 170
Descriptors DEC
BETA DECAY RADIOISOTOPES; BETA-MINUS DECAY RADIOISOTOPES; CARBOXYLIC ACIDS; CHARGED PARTICLES; DAYS LIVING RADIOISOTOPES; DISPERSIONS; ELECTRON CAPTURE RADIOISOTOPES; ELEMENTS; HOMOGENEOUS MIXTURES; INTERMEDIATE MASS NUCLEI; IONS; ISOTOPES; METALS; MIXTURES; MONOCARBOXYLIC ACIDS; NUCLEI; ODD-ODD NUCLEI; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC POLYMERS; PETROCHEMICALS; PETROLEUM PRODUCTS; POLYMERS; RADIOISOTOPES; RARE EARTH NUCLEI; THULIUM ISOTOPES

Optional Information

Notes
6 figs, 6 tabs, 12 refs
Secondary number(s)
STI/PUB--20(Vol.3)