Mixed Matrix Membranes (MMMs) for Gas Separation

Abstract

During the past few decades, membranes have attracted more attention in various types of gas-based separation processes due to their inherent advantages including relatively low energy consumption, low investment cost, ease of operation and adaptability, high efficiency, low energy consumption, and environmental friendliness. Furthermore, mixed matrix membranes (MMMs) have been touted as an alternative to polymer and inorganic membranes due to their high separation performance as they provide a synergy of the original properties of the inorganic and organic mix. The MMM could be produced either in a symmetric or an asymmetric shape through solution blending, in-situ sol gel method, and in-situ polymerization. The MMMs used in industrial applications are usually flat sheets or hollow fibers. In an attempt to ensure high selectivity and permeability during gas separation, different materials have been used to fabricate MMMs, which include glassy and rubbery polymers, as well as fillers such as zeolites, carbon molecular sieves, silica, metal oxides, metal–organic frameworks, and zeolite imidazolate frameworks. The MMMs’ fabrication challenges that include void formation and agglomeration, as well as the performance and optimization of these membranes, are discussed in this chapter. The chapter concludes by providing future research perspectives regarding the application of MMMs in gas separation.