Interaction of NpO2+ with Cl– in NaCaCl-type solutions at ionic strength of 6M: Effect of presence of Ca ion on interaction

Abstract

The interaction of NpO2+ with Cl– was studied using visible–near-infrared spectroscopy in NaClCaCl2NaClO4, NaClNaClO4, and CaCl2NaClO4 solutions with ionic strength (I) of 6M. The spectra of NpO2+ around 980 nm varied with Cl– concentration in the NaClCaCl2NaClO4 and NaClNaClO4 solutions at [Cl–] ≥ 3.5M, but not in the CaCl2NaClO4 solution. Assuming the 1:1 interaction between NpO2+ and Cl–, the apparent equilibrium constants at I = 6M were evaluated. The presence of Ca2+ was found to destabilize overall interaction between NpO2+ and Cl–. The observations were consistent with the density functional theory calculation.

Keywords

• Cl–
• Density Functional Theory Calculation
• Equilibrium Constants
• Ionic Strength
• NpO2+
• Presence of Ca2+