Synthesis and application of ZIF-67 on the performance of polysulfone blend membranes

Sodium nitrate and sodium sulfate are used to study the effect of ZIF-67 on the performance of polysulfone membranes. Zeolitic imidazolate frameworks (ZIFs) have a high surface area, thermally and chemically stable than any other metal–organic frameworks (MOFs) due to the presence of transition metals like cobalt. In this study, the concentration of ZIF-67 was varied from 0, 1, 3, 5 to 7 wt% in polysulfone membranes. It was observed that pure water flux was enhanced from 2.94 L/m2 h (using a pure polysulfone membrane) to 35.39 L/m2h for the membrane with 7 wt% ZIF-67 at 10 kgf/cm2. Also, at a high concentration of ZIF-67 in the membrane, due to aggregation of MOFs, rejection of salts and permeate collected slightly decreased. Hence, 5 wt% ZIF-67 is used as the optimum concentration for better performance in polysulfone membranes.