Thermodynamic Characterization of Sodium Alginate by Inverse Gas Chromatography

Abstract

This work addresses the surface properties and solubility parameters of sodium alginate (SA) using the inverse gas chromatography (IGC) technique. The dispersive component of the surface free energy,γSD, of the studied adsorbent surface was calculated in the infinite dilution region. The specific enthalpy of adsorption,ΔHS, the specific free energy of adsorption, ΔGS, and the specific entropy of adsorption, ΔSS, of solvents on SA were determined. The acidic KA and the basic KD parameters of the SA surface were calculated. The values obtained for KA and KD parameters indicated that the SA surface has a basic character. The interactions between 16 solvents and SA were investigated at a temperature range (373.2–398.2 K). The weight fraction activity coefficient,Ω1∞, Flory–Huggins interaction parameter, χ12∞, equation-of-state interaction parameter, χ12*, and effective exchange energy parameter, Xeff, of the SA–solvent system were estimated. The results indicated that all the studied solvents are poor solvents for SA. This means that it can be used in the packaging food and biomedical field. The solubility parameter of SA, δ2, was determined as 17.5 (cal/cm3)1/2.