Amino-functionalized ZIF-L crystals: Improved interfacial compatibility and pervaporation performance in mixed matrix membranes for phenol/water separation

This work focused on improving the pervaporation performance of Pebax® 2533 membranes cast on polytetrafluoroethylene substrates, by incorporating home-made bifunctionalized ZIF-L with amino groups and aromatic rings, to prepare MMMs for dephenolization from the aqueous solution. Amino groups in ZIF-L-NH 2 led to the enhanced interaction between the fillers and the matrix by forming hydrogen bonds, thus aminated fillers dispersed more homogeneously in MMMs than the non-aminated fillers and the MMMs possessed a better interface structure. Aromatic rings in ZIF-L-NH 2 made the membranes more organophilic and brought them a stronger affinity towards phenol. The separation performance of the MMM with 15 wt% fillers and 20 μm thickness surpassed most of the other phenol-selective membranes with the separation factor of 59.79 and the total flux of 1.93 kg/m 2 ·h for 1000 ppm phenol solution at 80 ℃. Notably, the MMMs maintained a good separation performance even when the phenol concentration of the feed solution extended to 18,000 ppm. In a 60 h long-term pervaporation, the MMM was stable. We believe that such MMMs design based on fillers with a ligand rich in aromatic rings and amino groups is a promising approach for high-performance dephenolization membranes.