Surprising olefin/paraffin separation performance recovery of highly aged carbon molecular sieve hollow fiber membranes by a super-hyperaging treatment

Carbon molecular sieve (CMS) hollow fibers derived from 6FDA(1):BPDA(1)/DAM(2), a well-studied polyimide precursor with attractive propylene/propane separation performance, were purposely treated to simulate long time aging under storage conditions. A simple, efficient post-aging thermal-treatment regeneration termed super-hyperaging is shown here to recover C3H6 permeance with satisfactory C3H6/C3H8 selectivity. A super-hyperaging temperature around 280 degrees C in air is shown to provide an optimum tradeoff in permeance and selectivity for highly aged samples. The regenerated CMS membrane displays performance well beyond the polymer permeance-selectivity tradeoff upper bound, and a hypothetical mechanism for the super-hyperaging recovery of aged CMS fibers is discussed herein.

Automated summary

The study demonstrates successful recovery of aged carbon molecular sieve (CMS) fibers through super-hyperaging technique, achieving satisfactory propylene permeance with optimal selectivity. A super-hyperaging temperature of around 280 degrees Celsius is shown to provide the best balance between permeance and selectivity. The regenerated CMS membrane surpasses the polymer permeance-selectivity tradeoff upper bound, with a hypothetical mechanism for the super-hyperaging recovery of aged CMS fibers discussed.