Effect of Polymer–Zeolite Interactions on the Separation Performance of Modified DD3R Membrane

ABSTRACT The effect of polymer–zeolite interactions was investigated by examining the coating parameters of cellulose acetate (CA) on the separation performance of DD3R membranes. Varying polymer concentrations and the number of coating stages, with an immersion time of 30 s, partially block nonzeolitic pores. Although low polymer solution concentrations result in higher blockage of nonzeolitic pores, a 30‐s immersion time minimally affects separation performance. Extending the immersion time to 15 min increases polymer–zeolite interactions and pore blockage. The selective behavior of the blocked pores for CO 2 enhanced the selectivity of the modified membrane for CO 2 /N 2 (113% of the theoretical perm selectivity value). This proves the hypothesis of using a selective polymer material to create a synergistic effect of the polymer with the zeolite layer in gas separation. In this synergy, the adsorption–diffusion mechanism in the DD3R zeolite pores and the solution–diffusion mechanism in the nonzeolite pores by CA play the gas separation role.