High Efficient UiO‐66‐NH2/PS Hierarchical Membrane for Vacuum Membrane Distillation

Abstract Membrane distillation (MD), a sustainable desalination technology by low‐grade heat, has garnered significant attention, but it suffers from low permeate flux and intensive energy. This work integrates hydrophilic metal–organic framework (MOF) into a hydrophobic polystyrene (PS) matrix, utilizing water capillary condensation within UiO‐66‐NH 2 to lower local vapor pressure and improve evaporation rate. Moreover, the confined evaporation enhancement effect facilitates the continuous evaporation of condensed water within these “reservoirs,” enabling the establishment of a dynamic equilibrium. The UiO‐66‐NH 2 near the vacuum side does not undergo condensation, further enhancing water vapor transport by providing favorable pathways for vapor diffusion. The UiO‐66‐NH 2 /PS‐HP membrane (hot‐pressed UiO‐66‐NH 2 /polystyrene fiber membrane) achieves an impressive flux of 137.6 L m −2 h −1 and a salt rejection rate of 99.95% under 70 °C and −85 kPa vacuum pressure, surpassing the performance of both commercial and most reported polymer membranes. Moreover, this UiO‐66‐NH 2 /PS‐HP membrane demonstrates excellent antifouling behavior, long‐term stability for 80 h, and scalability for large‐area fabrication (120 cm × 30 cm). This work provides valuable insights for developing high‐performance membrane distillation membranes for desalination applications.