Synergistically enhancing the antibacterial and antibiofilm activities of anion exchange membrane by chemically assembling gentamicin and N-chloramine layers

Biofouling is one of significant obstacles decaying the high separation performance and long-term stability of polymer membranes during the application. To explore the desirable anti-biofouling anion exchange membrane (AEM), in this work, a series of modified AEMs having surface antibacterial functional layers on surface has been prepared by using gentamicin and N-chloramine for electrodialysis (ED). The antibacterial functional layer on surface was constructed via chemical assembly. By using CuSO4 and H2O2 as the trigger, l-dopa was oxidized on surface of commercial AEM (Fuji type II) to form a carboxyl layer. Thereafter, gentamicin was chemically assembled via the amide condensation reaction. It was chlorinated with diluted NaClO solution to endow it with synergistic antibacterial activity by using gentamicin. Investigation demonstrates that the optimized membrane of P(l-Dopa)@GM-Cl has high antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Among them, flow cytometry shows that the antibacterial rate of P(l-Dopa)@GM-Cl against E. coli is more than 99%, which is much higher than original membrane (28.4%). P(l-Dopa)@GM-Cl exhibits the enhanced performance in inhibiting biofilm observed by scanning electron microscopy analysis. This work may provide a reference for the construction of anti-biofouling ion exchange membrane.