PEBA/Na-X Multilayer Hybrid Membrane for CO2 Separation: Influence of Na-X Zeolite Layer Synthesis Condition

Abstract

The effects of synthesis time and the number of synthesis layers were investigated on the synthesis of Na-X zeolite sublayer for fabricating a PEBA/Na-X hybrid membrane. The CO 2 /N 2 separation was considered as the objective function to obtain an effective Na-X sublayer. SEM and AFM studies of the synthesized sublayers reveal that 6 hour synthesis time and one synthesis layer give an Na-X sublayer (ZSL6-1) with sub-micron thickness (< 1µm), and roughness of 13 nm. The N 2 permeation ( 11900 GPU) shows the low mass transfer resistance through the ZSL6-1 sublayer. The ZSL6-1 sublayer in the hybrid structure of the membrane leads to the high stability of the multilayer structure via the anchoring effect of the polymer. Hydroxyl groups, along with positive and negative charges on the surface of the Na-X sublayer, cause to strong bonding of the polymer layer and prevent its delamination. The surface coverage of the sublayer by polymer has increased the mass transfer resistance just for N 2 and increase the perm-selectivity. These properties, along with the high affinity of the Na-X to the adsorption of CO 2 , results in a 56% increase in the perm-selectivity of CO 2 /N 2 ( ~ 70 ) compared to net PEBA ( ~ 40-50 ) and the recently reported hybrid membranes.