Permeability, solubility, and diffusivity of aniline in poly(ether-b-amide) membranes pertaining to aniline removal from aqueous solutions by pervaporation and sorption

This work dealt with the fundamental aspects of solubility, diffusivity, and permeability of aniline in PEBA 2533 pertaining to aniline removal from water via pervaporation and sorption, with an emphasis on membrane permeability determined via different approaches: (1) pervaporation experiments, (2) sorption experiments, and (3) direct measurements from pseudo steady state liquid permeation. The membrane exhibited high permselectivity for aniline separation via pervaporation, which was derived from the high solubility selectivity to aniline. The permeability of aniline in the membrane for pervaporative mass transfer was on the order of 105 Barrer, with a solubility and diffusivity of 105 mol/(m3∙Pa) and 8.3 × 10−12 m2/s, respectively, at 23 °C as determined from sorption experiments. Although it has been largely overlooked, caution should be exercised in determining or characterizing the membrane permeability based on different measurement techniques, and proper conversions are needed to rationalize and reconcile the permeability data. The sorption-desorption reversibility was investigated as well, which was relevant to aniline removal from water by cyclic sorption/desorption and steady state pervaporative separation.