Separation of hydrogen from carbon dioxide for sustainable H₂ production and CO₂ capture still faces great challenges due to the smaller size of H₂ and higher condensability of CO₂. Herein, a high-performance benzimidazole-linked polymer (BILP) membrane for hydrogen separation was directly prepared on α-Al₂O₃ substrate through a facile interfacial polymerization approach at room temperature. The separation performance of the BILP membrane were regulated by controlling the reaction time and the microstructure was systematically characterized. Molecular simulations were performed to deep understand the separation mechanism in the BILP membrane. The best performance membrane displays an extraordinary mixed gas selectivity of 40 for H₂/CO₂ together with outstanding H₂ permeance of 250 gas permeation units (GPU) at 473 K, far exceeding the Robeson's upper bound. Besides, the membrane can withstand high temperature and pressure, and also shows good H₂/N₂ and H₂/CH₄ selectivity. The excellent separation performance, coupled with high temperature and pressure resistance and easy preparation, render BILP membranes great potential for economic H₂ purification, H₂ recovery, and natural gas treatment.

New membrane materials with excellent water permeability and high ion rejection are needed. Metal-organic frameworks (MOFs) are promising candidates by virtue of their diversity in chemistry and topology. In this work, continuous aluminum MOF-303 membranes were prepared on α-Al2O3 substrates via an in situ hydrothermal synthesis method. The membranes exhibit satisfying rejection of divalent ions (e.g., 93.5% for MgCl2 and 96.0% for Na2SO4) on the basis of a size-sieving and electrostatic-repulsion mechanism and unprecedented permeability (3.0 L·m-2·h-1·bar-1·μm). The water permeability outperforms typical zirconium MOF, zeolite, and commercial polymeric reverse osmosis and nanofiltration membranes. Additionally, the membrane material exhibits good stability and low production costs. These merits recommend MOF-303 as a next-generation membrane material for water softening.

High permeable and selective membranes are expected to be a promising alternative for low cost and energy efficient CO₂ separation. However, the preparation and development of highly permeable and selective membranes are limited by the trade-off effect. Here, we prepared a stabilized high permeable and selective mixed matrix membrane based on the structural regulation of the NH₂-functionalized Co/ZIF-8 heterometallic nanoparticles (NH₂-Co/ZIF-8). The NH₂-Co/ZIF-8 can be homogeneously dispersed in the polymer via chelation of the ester group and the metal node in the methacrylate-terminated PEO and the acrylate-terminated PEO. The amphiphilic interaction between the polymer and NH₂-Co/ZIF-8 significantly increased the CO₂ solubility resulting in the boost of both CO₂ permeability and CO₂/N₂ selectivity. The best performance membrane exhibits a CO₂ permeability of 2916 Barrer and a CO₂/N₂ selectivity of 47, surpassing the Robeson's upper bond (2008) by a wide margin.