Ship-in-a-bottle, a new synthesis strategy for preparing novel hybrid host-guest nanocomposites for highly selective membrane gas separation

Organic-inorganic hybrid nanocomposites within polymeric matrices have potential as functional materials for membrane gas separation. We present a new synthesis strategy for preparing novel hybrid host-guest nanocomposites by encapsulating a metal-organic complex of a transient metal such as cobalt (Co) in zeolite Y cavities with the ship-in-a-bottle (SIB) synthesis method. Then, the encapsulated zeolite Y nanoparticles were embedded into the Matrimid (R) 5218 matrix to fabricate a novel type of mixed-matrix membranes (MMMs) for gas separation. Eventually, the effects of incorporating these types of synthetic fillers on CO2/CH4 permselectivity of MMMs were comprehensively studied. Incorporating an encapsulated polyaza macrocyclic Co-ligand complex into the polymer matrix endowed the resultant MMM with brilliant CO2 separation performance, together with an unusual/extremely desirable enhancement in CO2/CH4 selectivity. Indeed, MMM with 15 wt% encapsulated filler loading at 35 degrees C and 2 bar experienced a CO2 permeability of about 18.96 barrer and CO2/CH4 selectivity of about 111.7, which were more than two- and three-fold that of pure Matrimid performance. The proposed new method opens a new window to fabrication of purposeful MMMs for specific separation opportunities.