Potential of Polyurethane Functionalized Electrospun Nanofiber Membrane as Self-cleaning Water Filter

In the present research, a single-step electrospinning technique was implemented to develop homogeneous hydrophilic nanostructures with a self-cleaning characteristic based on non-woven polyurethane (PU) altered by quaternary ammonium salts (QAS). By transferring the nanofibrous structures to the polyethylene terephthalate substrate, the filtering membranes were fabricated. The fabricated PU and PU/QAS membranes were compared and characterized for assessing their self-cleaning properties. The synthesized nanofibers were mechanically tested and also characterized by scanning electron microscopy. At low trans-membrane pressure of 7.5 kPa, water permeation flux and biofouling effect of electrospun nanocomposite membrane performance were primarily studied by means of dead-end filtration. Following a 5-day filtration, the modified nanofibrous structure displayed promising results in the recovery of the flux after a day 3 and inhibited the development of biofilm as well. The tensile strength and modulus of PU-QAS were 7.5MP and 31.7% higher compared to PU membrane. The pore size was also observed to be 360n in PU, while for PU-QAS, it was observed as 340 nm. It was concluded that the developed PU/QAS membrane can be restored to its original flow properties by cleaning with tap water.