Mixed matrix membranes containing Cu-based metal organic framework and functionalized ionic liquid for efficient NH3 separation

Membranes that both have high gas permeability and selectivity is still challenging. Aiming to efficiently separate and purify ammonia-containing gases, this work constructed a novel ternary mixed matrix membranes (MMMs) by introducing functionalized ionic liquid ([Bim][NTf 2 ]) and Cu-based metal organic framework (CuBTC). It was proved that the interaction networks consisted of hydrogen bonding and electrostatic interactions are formed in the IL-based MMMs, leading to the improved compatibility, decreased crystallinity and amorphous morphology. The ammonia separation performance was evaluated through pure gases and mixed gases. The PCu3-IL100 MMM exhibits great ideal selectivities (α NH3/N2 = 530.1 and α NH3/H2 = 94.2) and optimal NH 3 permeability up to 3680.0 barrer, which is 260% and 129% higher than the pristine Pebax membrane and the PCu3 MMM, respectively. The improving NH 3 separation performance is attributed to the synergistic interaction of hydrogen bonding and Lewis acid-base between IL-based MMMs and NH 3 molecules, significantly increasing NH 3 solubility coefficient and solubility selectivity. The IL-based MMMs also show exceptional NH 3 mixed separation performance and long-term operation stability. • The formed interaction networks affect structure and property of IL-based MMMs. • IL-based MMMs achieves much higher NH 3 permeability and selectivity. • Hydrogen bond and synergetic Lewis acid-base interaction promotes NH 3 separation. • NH 3 transport in IL-based MMMs is decided by solubility rather than diffusivity.