Patent ID: 8226862
Filing Date: 2012-07-24
Classification: B01D

Abstract:
1. A process of making asymmetric flat sheet mixed matrix membranes with at least a 20% increase in selectivity compared to an asymmetric polymer membranes prepared from a corresponding polymer matrices, said process consisting of: a) dispersing molecular sieve particles in an organic solvent or a mixture of two or more organic solvents to form a molecular sieve slurry; b) dissolving a polymer or a blend of two polymers that serves as a continuous polymer matrix in the molecular sieve slurry and dissolving a second polymer in the molecular sieve slurry to functionalize an outer surface of said molecular sieve particles wherein said second polymer is selected from the group consisting of polyethersulfones, sulfonated polyethersulfones, hydroxyl group-terminated poly(ethylene oxide)s, amino group-terminated poly(ethylene oxide)s, or isocyanate group-terminated poly(ethylene oxide)s, poly(esteramide-diisocyanate)s, hydroxyl group-terminated polypropylene oxide)s, hydroxyl group-terminated co-block-poly(ethylene oxide)-poly(propylene oxide)s, hydroxyl group-terminated tri-block-polypropylene oxide)-block-poly(ethylene oxide)-block-polypropylene oxide)s, tri-block-poly(propylene glycol)-block-poly(ethylene glycol)-block-polypropylene glycol) bis(2-aminopropyl ether), polyether ketones, poly(ethylene imine)s, poly(amidoamine)s, poly(vinyl alcohol)s, poly(allyl amine)s, poly(vinyl amine)s, and cellulosic polymers; c) adding one or more organic solvents that cannot dissolve the polymer matrix to the molecular sieve/polymer slurry and stirring for a sufficient time to form a stable molecular sieve/polymer casting dope; d) casting a thin layer of the molecular sieve/polymer casting dope on top of a porous fabric support; e) evaporating the organic solvents for a sufficient time to form a wet mixed matrix membrane with a thin dense selective mixed matrix layer with a thickness equal to or greater than the particle size of the largest molecular sieve particles on said top of said porous fabric support; f) dipping the wet mixed matrix membrane into a cold water bath to generate a porous non-selective mixed matrix support layer below the thin dense selective mixed matrix layer by phase inversion; g) dipping the asymmetric mixed matrix membrane into a hot water bath to remove residue organic solvents in the mixed matrix membrane; and h) washing and drying the asymmetric flat sheet mixed matrix membrane.