Existence of protonated complexes of ethylenediaminetetraacetic acid with lanthanides in aqueous solutions

Journal Article · Sun Jan 01 04:00:00 EST 1989 · Sov. Radiochem. (Engl. Transl.); (United States)

OSTI ID:5837872

Afonin, M A

Ethylenediaminetetraacetic acid (EDTA) is widely used in various areas of radiochemistry, including the separation of rare earth elements (REE) by ion exchange and extraction methods. The discovery of the stoichiometry and determination of the constants of formation of complexes of REE with EDTA have been the subject of a large number of studies. We demonstrated the fact that no stable (pK/sub A/ = 1-2) complex acids of the lanthanides with EDTA exist in aqueous solutions. We calculated the equilibrium concentration of H/sup +/ ions considering the dissociation of the complex LnL/sup /minus// and the protonation of free EDTA/sup 5/minus//. Then the results obtained were treated and the reproducibility of the values of the dissociation constants K/sub A/ was detected both according to the series of lanthanides from Ce/sup 3+/ to Lu/sup 3+/ and according to the dependence of K/sub A/ on the pH.

• OSTI ID: 5837872
• Journal Information: Sov. Radiochem. (Engl. Transl.); (United States), Journal Name: Sov. Radiochem. (Engl. Transl.); (United States) Vol. 30:3; ISSN SVRDA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AMINO ACIDS
CARBOXYLIC ACIDS
CHELATING AGENTS
COMPLEXES
COMPLEXOMETRY
DISSOCIATION
EDTA
EQUILIBRIUM
HYDROGEN COMPOUNDS
HYDROGEN TRANSFER
ORGANIC ACIDS
ORGANIC COMPOUNDS
PH VALUE
QUANTITY RATIO
RARE EARTH COMPLEXES
RARE EARTH COMPOUNDS
STABILITY
SYNTHESIS