A hydrophilic, hydrostable porous metal organic framework (MOF) material-MIL-101 (Cr) was successfully doped into the dense selective polyamide (PA) layer on the polysulfone (PS) ultrafiltration (UF) support to prepare a new thin film nanocomposite (TFN) membrane for water desalination. The TFN-MIL-101 (Cr) membranes were characterized by SEM, AFM, XPS, wettability measurement and reverse osmosis (RO) test. The porous structures of MIL-101 (Cr) can establish direct water channels in the dense selective PA layer for water molecules to transport through quickly, leading to the increasing water permeance of membranes. With good compatibility between MIL-101 (Cr) nanoparticles and the PA layer, the lab made TFN-MIL-101 (Cr) membranes integrated tightly and showed a high NaCl salt rejection. MIL-101 (Cr) nanoparticles increased water permeance to 2.2 L/m²·h·bar at 0.05 w/v % concentration, 44% higher than the undoped PA membranes; meanwhile, the NaCl rejection remained higher than 99%. This study experimentally verified the potential use of MIL-101 (Cr) in advanced TFN RO membranes, which can be used in the diversified water purification field.

Highly stable water permeable thin film MIL-101(Cr) nanocomposite membranes for water treatment were created via in situ interfacial polymerization on a polyether sulfone support. Lab-made MIL-101(Cr) nanoparticles (∼200 nm) were used to introduce direct water channels to a dense polyamide layer, which increased water permeance. On changing the amount and the method of MIL-101(Cr) nanoparticle addition, the surface topography and internal structure of the membranes were changed, leading to different separating properties of the membranes. Measured at 10 bar with 2000 ppm Na₂SO₄ solution, nanosized MIL-101(Cr) increased water permeance to 3.91 L m⁻² h⁻¹ bar⁻¹ at 0.2 w/v%, 158% higher than undoped membranes; meanwhile, high Na₂SO₄ rejection was maintained. This study experimentally verified the potential use of MIL-101(Cr) in advanced thin film nanocomposite membranes, which can be used in diversified water purification fields, including desalination and the removal of organics.