Preparation of mixed matrix membrane
PSF beads (20 wt%) were stirred in the NMP at the room temperature for at least 12 h until the solution became homogeneous. For preparation of CNFs/PSF MMMs, a predetermined mass of the CNFs was dissolved in NMP; the concentration of CNFs was adjusted to 0.01–1 wt%. Fig. 1 referred to carbon nanofiber that used in this study. This CNF solutionadded to the polymer solution and the mixture allowed mixing for 6 h at room temperature. The dope solution was then degassed at the room temperature. The polyester non-woven fabric was attached to a clean glass plate,and after 10 min sonication the dope solution was extended onto the polyester fabric using a casting knife. The thickness of the ready membranes was between 150–175 mm. The whole composite was immersed in the precipitation bath including DI water after few seconds to start the phase inversion. After that the membranes were stored in water bath for at least 1 day to leach out the residual solvents completely.