Measurement and Modeling of Mean Ionic Activity Coefficient in Aqueous Solution Containing NaNO3 and Poly Ethylene Glycol

Abstract

Potentiometric investigation on {H2O+NaNO3+PEG1500} mixtures were made at T=308.15K, using electrochemical cells with two ion-selective electrodes, (Na+ glass) as the cation ion-selective electrode against (NO3- solvent-polymer PVC) as the anion ion-selective electrode. The mean ionic activity coefficients of NaNO3 were measured at different concentrations of NaNO3 and PEG. Maximum concentration of electrolyte and PEG were 1 mol/kg and 0.12 mol/kg, respectively. The experimental data was modeled by utilizing the modified Pitzer equation and the activity coefficient ratio of PEG was evaluated by using Maxwell’s cross differential relation.

Keywords

• activity coefficient
• polymer
• electrolyte solution
• ion-selective electrode