Zeolite Imidazole Frameworks Membranes for CO2/CH4 Separation from Natural Gas: A Review

Abstract

Carbon dioxide (CO2) which exists in natural gas is one of the undesirable impurities that can reduce the caloric power of the natural gas. The implications of CO2 on the economic loss of the natural gas processing have provoked the development of CO2 separation technology. In the past decades, membrane technology has emerged as an environmental friendly, economic feasible and easy-operating method in CO2 removal. ZIFs membranes presented to be relatively new materials, which possessed high stability and good performance in CO2 separation under harsh condition. The tunability of the pore apertures and plentiful diversity of the frameworks associated with ZIFs membranes provide massive potential for the researchers to enhance the properties of ZIFs membranes in CO2 separation. This review attempts to summarize the current performance of the ZIFs membrane in CO2/CH4 separation process, considering CH4 as the main constitutions in natural gas. Extensive study on molecular structures, membrane formation and separation mechanism is emphasized on ZIF-8 membranes owing to their exceptionally high CO2 permeability. To this end, separation performance involved in ZIF-8 membrane is discussed, which affected by the synthesis method, molar composition of the growth solution and modification of the supports.