Formation of high-performance 6FDA-2,6-DAT asymmetric composite hollow fiber membranes for CO2/CH4 separation

We report that 6FDA-2,6-DAT polyimide can be used to fabricate hollow fiber membranes with excellent performances for CO2/CH4 separation. In order to simplify the hollow fiber fabrication process and verify the feasibility of 6FDA-2,6-DAT hollow fiber membranes for CO2/CH4 separation, a new one-polymer and one-solvent spinning system (6FDA-2,6-DAT/N-methyl-pyrrolidone (NMP)) with much simpler processing conditions has been developed and the separation performance of newly developed 6FDA-2,6-DAT hollow fiber membranes has been further studied under the pure and mixed gas systems. Experimental results reveal that 6FDA-2,6-DAT asymmetric composite hollow fiber membranes have a strong tendency to be plasticized by CO2 and suffer severely physical aging with an initial CO2 permeance of 300 GPU drifting to 76 GPU at the steady state. However. the 6FDA-2,6-DAT asymmetric composite hollow fibers still present impressive ultimate stabilized performance with a CO2/CH4 selectivity of 40 and a CO2 permeance of 59 GPU under mixed gas tests. These results manifest that 6FDA-2,6-DAT polyimide is one of promising membrane material candidates for CO2/CH4 separation application. (C) 2002 Elsevier Science B.V. All rights reserved.