Synthesis and seawater desalination of molecular sieving zeolitic imidazolate framework membranes

• Dense ZIF membranes are prepared through bio-inspired polydopamine modification.
• ZIF membranes are developed for the first time for seawater desalination.
• The ZIF membranes show high water flux and ion rejection for seawater desalination.

Through bio-inspired polydopamine modification of the ceramic support surface, dense and reproducible zeolitic imidazolate framework (ZIF) membranes have been developed for the first time for seawater desalination by pervaporation. Demonstrated by both experimental and simulation studies, the developed ZIF membranes show high desalination performances attributing to the small pore size of the ZIF membranes, which is exactly in between the size of water molecules and hydrated ions. The ZIF membranes show a high stability in seawater. At 25, 50, 75 and 100 °C, the water fluxes through the ZIF-8 membrane are 5.8, 8.1, 10.8, and 13.5 kg/(m2·h), respectively, with a high ion rejection of over 99.8%, which is promising for seawater desalination by ionic sieving.

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