What is the acidity of a plutonium solution?

Abstract

The determination of the pH of a plutonium solution has traditionally depended on an electrode or a titration in the presence of a complexing agent. A new approach uses on the equilibrium distribution of the Pu oxidation states to estimate hydrogen ion concentration. The method is used to estimate the equilibrium constant of the first hydrolysis reaction of tetravalent plutonium.

Plutonium hydrolysis and the double double-point

“…If KH is also the correct value for the solution, the six expressions are exact [7]. In that case, the fourth root of computed [H+t agrees with the corresponding pH measurement.…”

“…The fourth power of the molar acid concentration in a Pu solution has recently been expressed by six formulas [7]. In order to estimate the numerical value of [H+t, an expression like H4WX is substituted with measured fractions oftri-and tetravalent plutonium [8].…”

“…3. Equation 4 Table 1 in [7]. However, the two sets of approximations need not be identical because they represent different computational approaches.…”

“…There is presently a disagreement about the numerical value of the equilibrium constant of the first hydrolysis reaction of tetravalent plutonium. According to recent textbooks and related monographs, that constant is uncertain by a factor of about ten [4][5][6][7]. A new method for discriminating between the differing claims is illustrated.…”

Nonequilibrium method for estimating the first hydrolysis constant of tetravalent plutonium

“…The traditional estimates ofK H are about 0.02-0.05 . Recent analyses of the distributions of the four oxidation states of plutonium have been used to estimate its numerical value [1][2][3][4][5][6]. The recent results reinforce the traditional estimates of K H .…”