MOLECULAR-TRANSPORT CHARACTERISTICS OF A CHLOROSULFONATED POLYETHYLENE GEOMEMBRANE IN THE PRESENCE OF AROMATIC ESTERS

Results of a study on sorption and diffusion of chlorosulfonated polye thylene geomembrane with methyl benzoate, ethyl benzoate, methyl salic ylate, iso-butyl salicylate, phenyl acetate, and diethyl phthalate in the temperature range 25-60 degrees C are presented. A gravimetric sor ption method is used to calculate the diffusion and permeation coeffic ients from the Fickian relationship. The diffusion results are depende nt on penetrant-membrane interactions, temperature, and on penetrant c oncentration. The values of diffusion coefficients range from 0.02 x 1 0(-7) cm(2) s(-1) for diethyl phthalate at 25 degrees C to 1.81 x 10(- 7) cm(2) s(-1) for ethyl benzoate at 60 degrees C. The activation ener gies for diffusion range from 21 to 50 kJ mol(-1). The values of heat of sorption ranged between 2.2 and 6.4 kJ mol(-1). Sorption results ar e also analyzed using a first-order sorption kinetic equation. Experim ental results and calculated parameters are used to discuss the transp ort behavior. None of the esters used have shown any chemical attack t oward the geomembrane.