RES³T - Rossendorf Expert System for Surface and Sorption Thermodynamics

Results from batch type experiments were modeled using the 2 SPNE SC/CE model developed by Bradbury and Baeyens. This work focused on the applicability of this model to the sorption of Np(V) on Na-montmorillonite under high saline conditions (0.1–3.0 M NaCl) in the pH range of 2–10 and in the presence of dissolved CO₂ (p(CO₂) = 10^−3.3 atm). Under ambient air conditions two additional surface complexation species had to be taken into account, which are ternary species involving one carbonate ligand (≡SONpO₂(CO₃)²⁻, ≡SONpO₂(CO₃)Na⁻). The gained set of complexation parameters was successfully tested over a wide range of Np(V) concentrations (10⁻⁴ to 10⁻¹² M) under Ar atmosphere and ambient air condition.