Debye-Huckel contributions to the Gibbs energy interaction parameters for ternary electrolyte plus non-electrolyte plus water systems

摘要

The Debye-Huckel and non-Debye-Huckel contributions to the Gibbs energy interaction parameters are investigated for electrolyte (E) + non-electrolyte (N) + water (W) systems. A method is proposed for calculating the interaction parameters, C (DH)(n), C-n(N), and C-n(T), which represent the Debye-Huckel, non-Debye-Huckel, and total contributions, respectively. Four ternary E + N + W systems are chosen and the interaction parameters are computed with different forms of the Debye-Huckel equation. Results show that: (1) the Gibbs energy interaction parameters between E and N can be divided into two parts: the Debye-Huckel contribution and the non-Debye-Huckel contribution, C-n(T)=C-n(DH)+C-n(N); (2) the signs and magnitudes of the Debye-Huckel contribution to the interaction parameters, C-n(DH), depend mainly on the change in the dielectric constant of the solvent due to the addition of the non-electrolyte into the solvent; and (3) when the addition of the non-electrolyte only affects slightly the dielectric constant of the solvent, C-1(DH) (indicating the Debye-Huckel contribution to the interaction parameter for E + N) has a very small value and consequently can be neglected. In general, C-1(DH) is large, even larger than C-1(N).