An antifouling and acid resistant loose NF membrane via synergic modification of PVP and PEI on PTFE substrate

Polytetrafluoroethylene (PTFE) with good resistance can be used under extreme conditions, however, its surface hydrophobicity greatly limits its wide application in water treatment field. In this work, the hydrophobic PTFE microfiltration (MF) membrane was innovatively modified into a hydrophilic loose nanofiltration (NF) via synergic effect of the deposited polyethyleneimine (PEI) and poly(vinylpyrrolidone) (PVP) with assistance of fluorocarbon surfactant (FCS), and then crosslinked by glutaraldehyde (GA). The surface morphology, porosity and aperture size of the obtained cPEI-PVP-FCS/PTFE (cPPF) membrane were characterized in detail. The resultant membrane showed good dye desalination performance with high Evans blue rejection of 98.5%, NaCl rejection of 13.4%, along with permeance of 192.1 L m−2 h−1·MPa−1. In addition, the membrane showed long-term stability and good acid resistance.