Highly Water-Permeable Metal-Organic Framework MOF-303 Membranes for Desalination

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.