(419j) Selective Separation of Hydrogen from C2H6 and CO2 through Pressed Natural Zeolite Membranes

Natural clinoptilolite mineral supplied by St. Cloud (New Mexico) company has high purity of clinoptilolite and almost no macroporosity. Disk membranes cut from clinoptilolite rocks and clinoptilolite composite membranes have been tested for gas separations in our lab[1],[2]. However scaling-up challenge of the mineral disk from rocks membrane limits its application in industrial membranes in gas separation. In this study, to get higher flexibility and have different aspect ratios, natural zeolite membranes were prepared by dry pressing clinoptilolite powders. The phase composition and morphology of the pressed membranes were characterized by XRD and SEM, respectively. Gas separation performance of these membranes have been evaluated with H2, C2H6 and CO2 single gas permeation tests. Experimental results show high selectivity as much as three times higher ideal selectivity for H2 over CO2 and C2H6 than would be predicted by Knudsen diffusion. 1.9 cm diameter disc with thickness of 1.3 mm modified by simple hydrothermal treatments and applied to the separation of hydrogen from CO2, and C2H6 demonstrated H2permeance as high as 1.03×10-6 mol m-2 s-1 Pa-1 combined with ideal selectivities of 10.1 (H2/CO2)and 8 (H2/C2H6) at 25 C; and 9.2 (H2/CO2), and 7.7 (H2/C2H6) at 200 C.