ASYMMETRIC MODIFIED CARBON MOLECULAR SIEVE HOLLOW FIBER MEMBRANES HAVING IMPROVED PERMEANCE

The present invention provides an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties and a process for preparing an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties. The process comprises treating a polymeric precursor fiber with a solution containing a modifying agent prior to pyrolysis. The concentration of the modifying agent in the solution may be selected in order to obtain an asymmetric modified CMS hollow fiber membrane having a desired combination of gas permeance and selectivity properties. The treated precursor fiber is then pyrolyzed to form an asymmetric modified CMS hollow fiber membrane having improved gas permeance.