Sorption properties of organic solvents in PEBA membranes

Commercially available polyether block amides (PEBAs) are important hydrophobic membrane polymers for the separation of organics from water. Therefore, in this study the sorption properties are reported for 21 solvents (water, alcohols, alkanes, aromatics, chlorinated hydrocarbons and ethers) in PEBA membranes. The sorption isotherms have been determined at different temperatures for solvent vapor activities up to 0.98. For all solvents it was found that the sorption is independent of temperature in the range between 30 and 80 °C. Two theoretical models have been tested to describe the experimental sorption isotherms. It was found that the Flory–Huggins theory gives only a qualitative description of the sorption isotherms, whereas the UNIQUAC model is able to describe the experimental data very well, i.e. nearly quantitatively.