NOVELTY - Membrane or fluid separation comprises a molecular sieve material; and a polyimide polymer comprising many first repeating units of amide compounds (I).    USE - (I) is useful for separating a fluid from a fluid mixture (comprising carbon dioxide/oxygen/helium and a gas such as methane and/or nitrogen) (claimed). (I) is useful for the production of oxygen-enriched air or nitrogen-enriched-air, and for the separation of carbon dioxide from hydrocarbons or nitrogen, and the separation of helium or hydrogen from various streams.    ADVANTAGE - (I) exhibits improved separation performance as asymmetric membranes. (I) provides consistent separation performance. (I) does not interact with components of the process streams such as organic solvents. (I) exhibits good permeabilities, and good permselectivities.    DETAILED DESCRIPTION - Membrane or fluid separation comprises a molecular sieve material; and a polyimide polymer comprising many first repeating units of amide compounds of formula (I).    R1 = a moiety having a composition of toluene compounds of formulae (a and b) and/or benzylbenzene compounds of formula (C);    R2 = a moiety having a composition of phenyl compounds of formula (q), biphenyl compounds of formula (s) and substituted phenyl compounds of formula (t); and    Z = -C(O)-, -O- or -S(O)2-.    An INDEPENDENT CLAIM is included for a method of separating a fluid from a fluid mixture comprising providing a hollow fiber membrane (I); contacting a fluid mixture with a first side of the membrane for causing a preferentially permeable fluid of the fluid mixture to permeate the membrane faster than a less preferentially permeable fluid to form a permeate fluid mixture enriched in the preferentially permeable fluid on a second side of membrane and a retentate fluid mixture depleted in the preferentially permeable fluid on the first side of the membrane; and withdrawing the permeate fluid mixture and the retentate fluid mixture separately, where the pressure gradient across the membrane is 100-2000 psi.