Carbon Capture via Thin‐Film Composite Membranes Comprising Polysulfone‐Coated Vertically Aligned <scp>ZIF</scp> ‐302 Nanoarrays

ABSTRACT Mesoporous zeolitic imidazolate frameworks ZIF‐302 nanocrystals possessing high CO 2 affinity, large surface area, and improved thermal stability find huge potential for carbon capture applications in treating post‐combustion flue gases. Thin film composite (TFC) membranes prepared by growing vertically aligned ZIF‐302 nanoarrays (V‐ZIF‐302) on cellulose acetate (CA) substrate in ZnO templates are expected to render excellent carbon capture performance. CO 2 extraction efficiency of TFC membranes was further enhanced by coating selective polysulfone (PSF) layer onto ZIF‐302 nanoarrays. CA/V‐ZnO/V‐ZIF‐302/PSF TFC membranes concocted via this unique method result in the formation of direct gas transport pathways inside the membrane structure. CO 2 transfer mostly occurring via molecular‐sieving openings present in ZIF‐302 nanoarrays leads to high CO 2 permeability of membranes. Formation of consecutive membrane layers was corroborated via Fourier transform infrared (FTIR) spectroscopy. Vertical alignment of ZIF‐302 deposited nanoarrays rendering thin layer of well‐defined structure was verified by scanning electron microscopy (SEM). Gas permeation measurements performed over prepared TFC membranes indicated improved CO 2 /N 2 selectivity with greater CO 2 permeance than pure polysulfone counterpart. As compared to bare PSF membrane having CO 2 permeability of 26 Barrer and CO 2 /N 2 selectivity of 12, the TFC membrane comprising CA/V‐ZnO/ZIF‐302/PSF layers exhibited CO 2 permeability of 77 Barrer and CO 2 /N 2 selectivity of 31.