Construction of a composite microporous polyethylene membrane with enhanced fouling resistance for water treatment

Abstract

In this research, a new kind of anti-fouling ultrafiltration (UF) composite membrane was fabricated by decorating poly (vinyl alcohol) on both the surface and cavities of a commercialized polyethylene (PE) separator. Zwitterionic l-cysteine was further tethered onto the composite membrane by “thiol–ene” click chemistry for pursuing enhanced anti-fouling properties. Results of XPS and FTIR verified the occurrence of each reaction procedure. Identified by water contact angle, SEM and AFM analysis, the composite membrane manifested superior hydrophilicity, smoother surface and better-distributed porosity. The permeability and anti-fouling property of the composite membranes and conventional polysulfone (PSf) membranes were tested by a crossflow filtration instrument. Results suggested that the composite membranes behave remarkable capacity in retaining BSA (increasing from the original rejecting ratio of 39.1% to the maximum 98.0%) and identical water flux to the PSf membrane. In addition, results of the fouling experiment revealed the composite membranes suffer much less flux decline than PSf membranes; and grafting zwitterionic l-cysteine can enhance the inhibition against foulants’ adhesion on the composite membrane, which guarantees favorable performances for long-term operation in BSA feed water. This study may render consideration on exploiting low-cost, sustainable UF membranes, and broadening the additional application of PE separators.