Ultrafast water flux through hot-pressed solution blown spun nanofiber-based thin film composite membranes for forward osmosis

A thin-film nanocomposite (TFNC) membrane prepared by a method comprising steps:

• a. preparing a spinning solution by mixing 5 wt % to 30 wt % by weight of the solvent of either (1) polysulfone with N-dimethyl formamide (DMF) or (2 polyethersulfone with N-methyl-2 pyrrolidone/toluene in a 2:1 ratio;
• b. feeding the polymer solution of (1) or (2) into a SBS system using a concentric nozzle to produce solution blown fibers;
• c. collecting the polymeric nanofibers evenly on a rotating vacuum collector to obtain a nanofiber mat on a polyester backing layer;
• d. hot-press post-treating the polymeric nanofiber membranes by positioning the membranes between a set of steel plates at 150° C. for 10 minutes or 175° C. for 6 minutes under a low loading of 0.5 tons/m2;
• e. removing the steel plates from the hot-press and cooling the steel plates;
• f. removing the polymeric nanofiber membrane samples from the steel plates;
• and
• h. preparing either (1) a trimesoyl chloride solution and a m-phenylenediamine solution or (2) a m-phenylenediamine graphene oxide solution;
• and either (ia) or (ib):
• ia. preparing the thin-film composite membranes by depositing a polyamide layer on top of the polymeric nanofiber membranes by an interfacial polymerization process using the trimesoyl chloride solution and a m-phenylenediamine of step (h);
• or
• ib. preparing the thin-film nanocomposite (TFNC) membrane by depositing a graphene oxide-incorporated polyamide layer on top of the polymeric nanofiber membranes via an interfacial polymerization process using the m-phenylenediamine graphene oxide solution of step (h).