Metallopolyimide precursor fibers for aging-resistant carbon molecular sieve hollow fiber membranes with enhanced selectivity
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorsRaja SWAIDAN, David J. HASSE, Madhava R. KOSURI, Canghai MA, Robert A. GAGLIANO, Henri CHEVREL
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Abstract
Metallopolyimide precursor fibers for aging-resistant carbon molecular sieve hollow fiber membranes having enhanced selectivity include transition metal cations complexed with electronegative regions of a polyimide. CMS membranes are made by pyrolyzing the metallopolyimide precursor fibers. The cations are introduced by including, in the spin dope composition used to extrude the fibers, either a salt of the transition metal and an inorganic anion or a transition metal/organic ligand complex.
Claims21
A method for producing a metallopolyimide precursor fibers for aging-resistant carbon molecular sieve hollow fiber membranes having enhanced selectivity, comprising the steps of:
- ejecting a bore fluid from a circular opening in a hollow fiber spinneret;
- preparing a spin dope composition comprising a polyimide dissolved in a solvent;
- extruding the spin dope composition from an annular opening that surrounds the circular opening;
- allowing the extruded core spin dope composition to traverse an air or inert gas gap to produce a nascent hollow fiber;
- allowing the nascent hollow fiber to travel through a coagulation bath of a non-solvent where still-dissolved portions of the polyimide in the nascent hollow fiber are solidified via phase inversion;
- washing the solidified fiber with a wash liquid to remove solvent from the solidified fiber, the wash liquid having cations of a transition metal dissolved therein, the dissolved cations diffusing into the solidified fiber and complexing with electronegative regions of the polyimide;
- and
- drying the solidified hollow fiber.
Dependencies are inferred from the claim text.