High performance of multilayer thin-film composite membranes with hyperbranched polyether-based copolyimide separation layers for CO2 separation

Multilayer thin-film composite membranes with hyperbranched polyether-based polyimide separation layer for CO₂ separation were synthesized by interfacial polymerization. The hyperbranched polyimide layer was synthesized via triamine-based polyetheramine (Jeffamine® T403) as the core. The effects of the polymerization time, and the monomer concentration on the gas permeation-separation performance were investigated. The effect of the addition of the second amine monomer was also investigated. The result showed that incorporating the second comonomer into the aqueous phase improved the gas permeation-separation performance. The optimum membranes with a hyperbranched copolyimide layer synthesized by using the equimolar Jeffamine® T403 and Jeffamine® ED2003 showed a high CO₂ permeance of 1085 GPU accompanied by a high ideal separation factor of 106.7. The effects of the operating temperature, the operating pressure, and the aging time on the gas permeation-separation performance were investigated. The results showed the membranes had good anti-plasticization and anti-aging properties. The separation properties for the CO₂/N₂ mixture in the dry state and in the humidified state were also evaluated. The effects of the pressure ratio and stage cut on the product purity and recovery were investigated. The results showed great practical application potential in the efficient removal of CO₂ from the CO₂/N₂ mixture.