Mutual influence in permeation of CO2-containing mixtures through a SAPO-34 membrane

The presence of adsorbed CO significantly affects the permeation of weakly adsorbed species in zeolite membranes. At the same time, CO is itself influenced by the presence of another component, deviating its permeation with respect to the single-gas condition. In this work, we investigated the mutual interaction between CO and the other permeating gases through SAPO-34 zeolite membranes for several binary mixtures with H, N or CH, varying temperature (25-100 °C), feed pressure (200-1000 kPa) and CO composition (0.05-0.95). We used a validated model (Zito et al., J. Membr. Sci. 564, 2018, 166-173) considering the competition between surface and gas translation diffusion. CO permeance is found higher in mixture with H in the whole range of operating conditions investigated, whereas CH slows down CO permeation. SAPO-34 shows a selectivity in mixture quite higher from the one evaluated from the permeance of single gas. The choice of appropriate operating conditions allows high permeance and selectivity, making SAPO-34 particularly suitable for CO separation.