Following the discovery by researchers at UOP on Mixed Matrix Membranes (MMMs), the
latest emerging membrane materials comprise molecular sieve entities embedded in a polymer matrix.
This type of materials can potentially surpass the “upper bound” limit of the permeability-selectivity
relationship by means of combining the easy processability of polymers with the superior gas separation
properties of rigid molecular sieve materials. It is well-known that the success of MMMs in gas
separation mainly lies on the proper selection of inorganic and polymeric materials and the approaches
to obtain an intimate polymer-zeolite interface as well as a practical membrane configuration. Since
then, an intensive research has been devoted to improve the interface quality by developing some
modification techniques, such as the silane modification on the zeolite surface, the introduction of
compatibilizers between polymer and particle phases, and high membrane processing temperature. On
the other hand, in view of MMM configuration, to meet a high productivity requirement for the
industrial application, the asymmetric hollow fiber membrane is a preferred configuration due to its
desirable characteristics like large surface-to-volume ratio and high flux. Hence, this chapter will briefly
outline the concept, materials selection, and challenges of MMMs containing molecular sieves in the
polymer matrix. Subsequently, it will focus on the key of mixed matrix hollow fiber membrane
fabrication and introduce attractive avenues to overcome its challenges for gas separation applications.
Keywords: Mixed matrix membranes, gas separation, upper bound limit, zeolite surface modification,
hollow fiber membranes.
