Hydrophilic Al-based MOF mixed-matrix membranes enabling selective water transport for efficient air dehumidification

The control of air humidity has become a critical challenge amid rapid industrialization and urbanization. Membrane-based dehumidification offers an energy-efficient alternative to conventional methods, yet its performance is often constrained by the inherent trade-off between permeability and selectivity. The mixed-matrix membranes (MMMs) incorporating nanofillers present a promising strategy to overcome this limitation. In this work, two hydrophilic aluminum-based metal-organic frameworks (Al-MOFs), CAU-23 and MIL-160, were incorporated into Pebax®1074 matrix to fabricate MMMs for air dehumidification. The introduction of hydrophilic Al-MOFs particles enlarges the inter-chain spacing in polymers and increases the fractional free volume (FFV), thereby enhancing water vapor permeability. Simultaneously, the nanochannels formed by the Al-MOFs provide preferential adsorption and transport pathways for water molecules, leading to markedly improved water vapor selectivity. Owing to its superior hydrophilicity, the MIL-160/Pebax membrane achieved higher H 2 O/N 2 separation performance (119 % up) than the CAU-23 counterpart (42 % up) relative to the pure counterpart. At an optimal loading of 5 wt%, the MMMs exhibited simultaneous improvements in both water vapor permeability and selectivity, this concurrent breakthrough underscores the strong potential of hydrophilic Al-based MOF MMMs for scalable application in industrial dehumidification processes.