Publications

The Pebax polymers are well-known in the gas-separation field since they are highly effective at separating CO₂ from other gases such as N₂ or CH₄. However, the CO₂ separation performance of Pebax membranes has been demonstrated to vary significantly from different sources, even for the same Pebax grade from the same supplier and prepared/analyzed under similar conditions. Reported CO₂ permeabilities range from 50 to over 400 Barrer, and corresponding CO₂/N₂ selectivity values lie between ∼30 and >70. In this work, available literature data for membranes fabricated from various grades of Pebax are first summarized and compared. The factors responsible for the considerable disparity in separation performance are then identified, focusing on the influence of methods, instrumentation and measurement conditions employed for gas-permeation analysis. With these factors in mind and to overcome experimental variation, we propose a comprehensive checklist of protocols for systematic single- and mixed-gas permeation tests related to carbon capture.