Abstract: 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.

Abstract: Disclosed herein is a method of making a crosslinked membrane such as a crosslinked hollow fiber membrane. The method comprises (a) preparing a polyimide polymer comprising carboxylic acid functional groups from a reaction solution comprising monomers and at least one solvent; (b) treating the polyimide polymer with a diol at esterification conditions to form a monoesterified polyimide polymer; (c) forming a monoesterified polyimide membrane or dense film from the monoesterified polyimide polymer; and (d) subjecting the monoesterified polyimide membrane or dense film to transesterification conditions under a CO2 atmosphere to form a crosslinked polyimide membrane or dense film.

Abstract: A composite structure for capturing a gaseous electrophilic species, the composite structure comprising mesoporous refractory sorbent particles on which an ionic liquid is covalently attached, wherein said ionic liquid includes an accessible functional group that is capable of binding to said gaseous electrophilic species. In particular embodiments, the mesoporous sorbent particles are contained within refractory hollow fibers. Also described is a method for capturing a gaseous electrophilic species by use of the above-described composite structure, wherein the gaseous electrophilic species is contacted with the composite structure.

Abstract: Carbon molecular sieves (CMS) membranes having improved thermal and/or mechanical properties are disclosed herein. In one embodiment, a carbon molecular sieve membrane for separating a first and one or more second gases from a feed mixture of the first gas and one or more second gases comprises a hollow filamentary carbon core and a thermally stabilized polymer precursor disposed on at least an outer portion of the core. In some embodiments, the thermally stabilized polymer precursor is created by the process of placing in a reaction vessel the carbon molecular sieve membrane comprising an unmodified aromatic imide polymer, filling the reaction vessel with a modifying agent, and changing the temperature of the reaction vessel at a temperature ramp up rate and ramp down rate for a period of time so that the modifying agent alters the unmodified aromatic imide polymer to form a thermally stabilized polymer precursor.

Abstract: 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.

Abstract: A composite structure for capturing a gaseous electrophilic species, the composite structure comprising mesoporous refractory sorbent particles on which an ionic liquid is covalently attached, wherein said ionic liquid includes an accessible functional group that is capable of binding to said gaseous electrophilic species. In particular embodiments, the mesoporous sorbent particles are contained within refractory hollow fibers. Also described is a method for capturing a gaseous electrophilic species by use of the above-described composite structure, wherein the gaseous electrophilic species is contacted with the composite structure.