Gas Separation Membranes

AbstractMembrane‐based gas separation is rapidly growing by serving as one of the important industrial gas separation technologies. The market size and a number of emerging applications are expanding because membrane technology provides a number of benefits in terms of energy saving and capital cost. Polymeric membranes are dominating materials in this field owing to their excellent processability, easy scale‐up, and feasibility in various modules. Various inorganics, including carbons, silica, and zeolites, ceramics, and metal membranes have been also extensively studied for more specific gas separation applications where polymeric membranes cannot serve. More recently, ultrapermeable polymeric membrane materials provided new ways to develop advanced membrane materials for competing with conventional gas separation technologies to treat large volume of gas streams on a more practical and economic basis. Current membrane‐based gas separations have been applied mainly for air separation, hydrogen separation, vapor/gas separation, and carbon dioxide separation. Other separation applications, such as olefin/paraffin, low grade O2/air, organic/organic separations, and ion‐conducting membrane from oxygen, are still actively being developed. In this article, we will review gas separation membranes from basics to their applications in terms of fundamental transport mechanism, membrane types, and applications. In addition, we will summarize the state‐of‐the‐art membrane materials and applications, and briefly provide an outlook for future development.