Adsorption Behaviors of Glycerol from Biodiesel on Sulfonated Polystyrene-Divinylbenzene Resins in Different Forms

摘要

The mechanisms of glycerol adsorption from biodiesel onto the sulfonated resins in both the hydrogen form (1180H) and sodium form (ll80Na) were investigated. 1180H displayed higher adsorption capacity of glycerol in comparison to 1180Na. Parameters from the four isotherm models indicated that the adsorption process for 1180H was non-ideal, physical, and endothermic but exothermic for 1180Na. The values of Gibbs free energy change (△G_0) and entropy change (△S_0) suggested that the adsorption processes for both 1180H and 1180Na occurred spontaneously with an increase in randomness of the system. The isosteric heats of adsorption (△H_x) for glycerol on both 1180H and 1180Na implied that interactions between the glycerol molecules and these modified resins were dominated by strong hydrogen bonding and that there existed an adsorbate-adsorbate mutual attractive interaction. The existence of hydrogen bonding was also confirmed by infrared spectra.