Separation of mixture components over membrane composed of a pure molecular sieve

A process for the separation of components of a gaseous or liquid mixture having at least two components which comprises contacting a feedstream of the mixture with an upstream face of a non-composited, microporous membrane comprising a continuous array of crystalline molecular sieve material under separation conditions such that at least one component of the mixture has a greater steady state permeability through the membrane than at least one of the remaining components of the mixture, and recovering the component having the greater permeability on the downstream side of the membrane after contact with and passage through the membrane.