Supersonically blown nylon-6 nanofibers entangled with graphene flakes for water purification

Abstract

Water purification membranes, capable of purifying a few to tens of milliliters of aqueous methylene blue solution in a minute, were produced by supersonically blowing graphene flakes with a nylon-6 polymeric solution. The solution-blown nylon-6 nanofibers became entangled with graphene flakes thereby locking the graphene flakes within the frame of the bendable two-dimensional film structure. This method, which yielded a 5 × 7 cm²-sized membrane in less than 10 seconds, is commercially viable owing to fast fabrication and scalability. We show that our water purification device allows a flow rate range of 0.3–4 L h⁻¹ with a membrane area of just 5 cm², under a pressure difference of 0.5–3.5 bar. If the membrane were scaled up to 0.5 m², it could provide 300–4000 L h⁻¹ flow rate, an ample supply for home use.