Enhanced O₂/N₂ separation by QuaternizedMatrimid/Multiwalled carbon nanotube mixed-matrix membrane

The air separation (O₂/N₂) based on polymeric membranes is critical because it is more energy efficient than traditional methods. Dense polymeric membranes are now the main stay of industrial processes that generate oxygen and nitrogen enriched gas. Though, regular polymeric membranes often fall short of selective pressure demands because O₂ and N₂ gases have such comparable equivalent diameters. While polymer composites have their benefits, nanocomposite (NCs) allows for the production of high-performance barriers. Utilising Matrimid® 5218 (Matrimid) as the base framework and multiwall carbon nanotube (MWCNT) as the filler, a novel NCs for O₂/N₂ separation was developed. Both matrimid and MWCNTs were chemically modified quaternization and functionalizing the MWCNTs. The membranes were casted using solution casting with a combination of quaternized matrimid and functionalized multi-walled carbon nanotubes (f-MWCNT). When f-MWCNT was added to quaternized matrimid, it created interfacial compatibility, which increased O₂/N₂ selectivity and permeability by 65 % and 35 %, respectively. In the current study, increasing O₂ diffusivity and O₂/N₂ solubility selectivity resulted in improved performance, this paves a way for manufacturing innovation.