Design, fabrication, and physicochemical characterization of polyamideimide membranes containing ZIF-8 and CMS particles for potential gas separation applications

Abstract

The development of hybrid membrane materials with excellent permeance and selectivity applied for gas separation has been the focus of world attention. However, the development of membranes with efficient separation performance remains a great challenge.The ZIF-8 nanocrystals were prepared by a precipitation reaction with Zinc metal cluster and 2-methylimidazole, whereas the carbon molecular sieves (CMS) were synthesized by pyrolysis of polyamideimide (PAI) polymer. The successful formation of ZIF-8 nanocrystals was evident from the rhombic octahedron shape, and EDX confirms the presence of Zn metal cluster and methylimidazole linker. The ZIF-8 and CMS nanoparticles incorporated PAI membranes were prepared using the phase inversion technique with varying loading wt.% of 1, 2, and 3%. PAI/ZIF-8 and PAI/CMS membranes cross-sectional morphology confirmed that synthesized nanoparticles were well embedded through the PAI membrane. The PAI/ZIF-8 (3 %) membrane, thin dense skin top layer, and well-defined honeycomb porous substructure were observed. It was noticed that the PAI/ZIF-8 (1 wt%) membrane had shown endurance for ultimate strain up to 8.25 % which is comparatively higher than the PAI/CMS membranes. However, both the ZIF-8 and CMS membranes had shown a decrease in the mechanical stability at the higher filler loading of 3 wt% which could be due to the increased brittleness due to the aggregation of filler particles at the higher loading. Thus, the inclusion of ZIF-8 and CMS particles in the PAI matrix positively altered the physicochemical properties of the resulting hybrid membranes, which could help them achieve remarkable gas permeance and selectivity.