Original scientific paper

https://doi.org/10.5562/cca1952

Voltammetric Study of Uranyl–Selenium Interactions. Part 2. Uranyl(V) Selenate Complex

Marina Zelić ; Division for Marine and Environmental Research, Ruđer Bošković Institute, P.O. Box 180, HR-10002 Zagreb, Croatia
Ivanka Pižeta ; Division for Marine and Environmental Research, Ruđer Bošković Institute, P.O. Box 180, HR-10002 Zagreb, Croatia
Renata Djogić ; Division for Marine and Environmental Research, Ruđer Bošković Institute, P.O. Box 180, HR-10002 Zagreb, Croatia

Abstract

Under the influence of recently published papers and some older own results, complex formation
in uranyl(VI)–selenium(VI) system was reinvestigated at the ionic strengths of 0.1 and 3.0 mol L–1. Using
electrolyzed selenate solutions (and square-wave voltammetry as a measuring technique) two coordination
species at the higher electrolyte concentration (log β1 = 1.48 ± 0.01, log β2 = 2.4 ± 0.1) were recognized, in
agreement with the literature data based on other experimental methods. For successful interpretation of
the voltammetric data, previously unknown weak complex (log β01=0.7 ± 0.1) of the reduction product,
i.e. uranyl(V) should also be included in the model. At the lower electrolyte concentration (0.1 mol L–1),
formation of complexes other than UO2SeO4
0 cannot be unambiguously confirmed due to the narrow ligand
concentration range.
Concerning the number of coordination species and their stability constants, seemingly different results
that arise from voltammetry and other (independent) experimental methods reflect the fact that the former,
in addition to the complexation of initially present metal ion, "sees" the coordination of its reduction
product with the ligand of interest, too. When both processes are taken into account during treatment of
voltammetric data, such differences disappear. (doi: 10.5562/cca1952)

Keywords

uranyl; selenate; square wave voltammetry; complex formation; stability constants

Hrčak ID:

101903

URI

https://hrcak.srce.hr/101903

Publication date:

3.5.2013.

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