Premium
Characterization of uranium(VI) in seawater 1
Author(s) -
Djogić Renata,
Sipos Laszlo,
Branica Marko
Publication year - 1986
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1986.31.5.1122
Subject(s) - uranyl , uranium , seawater , chemistry , carbonate , bicarbonate , polarography , inorganic chemistry , artificial seawater , ion , nuclear chemistry , geology , materials science , oceanography , organic chemistry , metallurgy
The physicochemical characterization of uranium(VI) in seawater is described on the basis of species distribution calculations and experiments using polarography and spectrophotometry in artificial seawater at elevated uranium concentrations. Various dissolved uranium(VI) species are identified under different conditions of pH and carbonate concentration. Below pH 4, the hydrated uranyl ion is present in the “free” state (forming “labile” complexes). Above pH 4, a stepwise coordination of uranyl by the carbonate ion occurs. The monocarbonate complex is formed in the pH range 4–5, the bicarbonate uranyl complex between 5 and 6. Above pH 8, uranium is present predominately as the tricarbonate and to a smaller extent as a trihydroxide complex. There is satisfactory agreement between our experiments and the theoretically computed distribution of uranium(VI) in seawater based on published stability constants. The experiments done at higher concentrations are justified by theoretical distributions showing that there is no great difference in species distribution between the uranium at concentrations of 10 −4 and 10 −8 mol dm −3 .