Preparation and gas separation properties of Zeolitic imidazolate frameworks-8 (ZIF-8) membranes supported on silicon nitride ceramic hollow fibers

Abstract Zeolitic imidazolate frameworks (ZIFs) have attracted great attention due to their potential applications in gas adsorption, catalytic membrane reactors, chemical sensing and gas separation. To achieve the massive industrial application, a number of attempts have been made to prepare supported-ZIF membranes. We successfully synthesized a well-intergrown continuous ZIF-8 membrane on the outer surface of silicon nitride hollow fibers by a one-step hydrothermal method. Through controlling ZIF-8 nucleation and growth rates, the membranes were compact and well-coated. Single gas permeation of H 2 , N 2 and CO 2 at 25 °C, 0.25 MPa indicated the sieving behavior of the obtained membranes. N 2 permeance did not change with permeation time, while H 2 permeance increased in the beginning and keep steady at 8.35×10 −7 mol/m 2 Pa s due to the high storage properties of ZIF-8, and CO 2 permeance decreased in the first hour, then maintained at 1.15×10 −7 mol/m 2 Pa s due to the strong CO 2 adsorption in the ZIF-8 and the cooperative interactions of adsorbed CO 2 molecules with CO 2 passing through. The H 2 /CO 2 separation factor of 11.67 could be achieved in the separation of 50%H 2 /50%CO 2 mixture.