Molecule design of effective C2H4/C2H6 separation membranes: From 2D nanoporous graphene to 3D AHT zeolite

It is of great importance and challenge to explore effective membranes with optimal pore structures from diverse porous materials to replace energy-intensive cryogenic distillation processes for C2H4/C2H6 separation because of their similar physical properties. In this work, we proposed a strategy to screen the ideal 3D zeolite membrane by matching the zeolite structure to the designed 2D nanopore. Here, we found out the ideal AHT zeolite membrane with elliptical windows similar to the designed graphene-embedded 22-crown-8 ether pore with ultrahigh selectivity of C2H4/C2H6 mixtures via molecular dynamics simulations. The results demonstrate that the AHT zeolite membrane only allows the transport of C2H4 based on molecular size exclusion, which is validated by density functional theory calculations. Furthermore, the permeation performance studies of pure components demonstrate that the AHT zeolite membrane exhibits a C2H4/C(2)H(6 )selectivity of around 100 and a C2H4 permeability of 958 Barrer, superior to most of reported membrane materials.