Synthesis, characterization and single gas permeation properties of NaA zeolite membrane

Single gas permeation properties of the NaA zeolite membranes were studied. The permeance of H2, O2, N2 and n-C4H10 decreased as the molecular kinetic diameter of the gases increased. At 298 K and under pressure difference of 0.10 MPa, the permselectivity of H2/N2, H2/n-C4H10 and O2/N2 were 20.1, 106 and 2.61, respectively, which were much higher than those of the corresponding Knudsen diffusion ratios of 3.74, 5.39 and 0.96. With increasing temperature, the gas permeance increased and the permselectivity of H2/N2, H2/n-C4H10 and O2/N2 slightly decreased. All these properties indicated that the gases mainly permeated through the channels of NaA zeolite and the gas permeation was predominantly controlled by the molecular sieving effect of NaA zeolite membrane. However, the permeation of n-C4H10 indicated that the NaA zeolite membranes had certain defects with diameters larger than the pore size of NaA zeolite.