Hydrolysis of protactinium(V).II.Equilibrium constants at 40 and 60 degrees C: A solvent extraction study with TTA in the aqueous system Pa(V)/H$_2$O/H$^+$/Na$^+$/ClO$_{4^-}$
Résumé
The hydrolysis of protactinium (V) was studied at tracer scale (ca. 10(-12) M) with the solvent extraction method involving the aqueous system: Pa(V)/H2O/H+/Na+/ClO4- at 40 and 60degreesC for three values of ionic strength. Extraction experiments were conducted using the chelating agent thenoyltrifluoroacetone (TTA) in toluene. Hydrolysis constants are reported for each ionic strength investigated. An SIT modeling is presented and extrapolated constants to zero ionic strength are derived, as well as interaction coefficients involving Pa(V) and perchlorate ions.