Interaction of Inert Gases with Ionic Melts: Solubility of He, Ar, N2, O2 and CH4 in the (Na,K)NO3 Eutectic Solvent

Abstract

The solubility of He, Ar, N2, O2 and CH4 was determined in the (Na,K)NO3 equimolar mixture by using a high-sensitivity manometric technique. The experimental findings are in agreement with the general trends valid in the case of weak solute-solvent interactions: positive heat of solution and solubilities inversely proportional to molecular size of the solute gases. For instance at 533 K the solubility constants are: 3.5 × 10–8, 1.3 × 10–8, 1.0 × 10–8, 0.97 × 10–8, 0.88 × 10–8 mol cm–3 bar–1 for He, Ar, O2, CH4 and N2 respectively. For the various systems the ΔH values range between 16.5 and 18.5 kJ mol–1 in the temperature interval 500–600 K. All the results are discussed in terms of the Uhlig-Blander solubility model.