Preparation of Metal-Organic Framework/Polyvinylidene Fluoride Mixed Matrix Membranes for Water Treatment

Metal-organic framework (MOF)-based mixed matrix membranes have become a research hotspot in separation field owing to the compatibility between MOF particles and the polymeric matrix. Herein, three types of MOF materials (MW-MIL-101(Cr), MW-UiO-66, and MW-ZIF-8) were successfully synthesized with the microwave-assisted solvo/hydrothermal method. Also, the reaction times of MW-UiO-66 and MW-MIL-101(Cr) are effectively shortened to 5 and 30 min, respectively. Subsequently, high-performance MOF/polyvinylidene fluoride (PVDF) mixed matrix membranes were fabricated via the phase inversion method for water desalination. Compared with the pristine PVDF membrane, the introduction of hydrophilic MW-MIL-101(Cr) and MW-UiO-66 crystals significantly increases water permeability and salt rejection of the mixed matrix membrane because the ordered pore structure is beneficial for selective permeability to salt ions. For the mixed matrix membrane with a PVDF concentration of 20 wt % and MW-UiO-66 doping amount of 30 wt %, water permeability can reach up to 72.57 L.m(-2).h(-1).bar(-1), along with NaCl rejection (96%) being between commercial NF90-4040 (91%) and SWC6-4040 (99%) membranes. In addition, the mixed matrix membrane possesses good cycle stability and potential commercial prospects.