Sandwich-type H2/CO2 membranes comprising of graphene oxide and sodalite crystals with adjustable morphology and size

Sandwich-type membranes comprising of graphene oxide (GO) as a "bun" and sodalite (SOD) nanocrystals with different morphologies and sizes as an inner layer were prepared. First, the SOD nanocrystals with spheroidal (size of 30 nm) and flake-like (size of 150 nm) morphologies were synthesized from precursor suspensions containing the same amount of GO as a modifier but different amounts of water. Second, the SOD nanocrystals with different morphologies and sizes were deposited between two GO layers to form the sandwich-type membrane. The performance of the sandwich-type membranes in H-2/CO2 gas separation was optimized by tuning the properties of the SOD inner layer. The membrane containing spheroidal SOD nanocrystals showed higher H-2 permeance of 4003 +/- 1965 GPU and H-2/CO2 selectivity of 45.5 +/- 1.7 at 25 degrees C in comparison to the pristine GO membrane (1642 +/- 145 GPU and H-2/CO2 selectivity of 11.2 +/- 2.1).