SORPTION EQUILIBRIA OF PYRIDINE-DERIVATIVES IN AQUEOUS-SOLUTION ON POROUS RESINS AND ION-EXCHANGE RESINS

Studies have been made of the sorption equilibria of pyridine, picoline and lutidine in aqueous solution on ion-exchange and porous resins. The sorption behaviors of these pyridines on strong acid ion-exchange resin can be expressed by the Langmuir isotherms, and those on both weak acid ion-exchange and porous resins by the Freundlich isotherms. The sorption mechanisms followed either a neutralization reaction with the H-form ion-exchange resins, or a hydrophobic interaction with the porous resins. Methanol content of the aqueous solution as well as solution pH was found to have a significant effect on the sorption of pyridines. Furthermore, the separations of these pyridines from each other were examined for three binary solute solutions in a batch mode. The pyridines were sorbed preferentially on the resins in the following sequence: pyridine < 3-picoline < 3, 5-lutidine where the selectivity increased as follows: strong acid ion-exchange resin < weak acid ion-exchange resin < porous resin.