Preparation of chlorine-resistant and regenerable antifouling nanofiltration membrane through interfacial polymerization using beta cyclodextrin monomers.

Constructing membrane with good chlorine resistance and antifouling properties is considered to be important challenges confronting membrane applications. In this study, a composite nanofiltration (NF) membrane (β-CD/PES) was prepared by interfacial polymerization using beta cyclodextrin (β-CD) monomers. Subsequently, the β-CD-based (AZ-β-CD/PES) membrane was prepared by assembling azobenzene labeled zwitterions into the hydrophobic internal cavity of β-CD via host-guest interaction. The optimized membrane exhibited slight change in water flux and rejection under chlorine environment. The AZ-β-CD/PES membrane also displayed an evidently lower loss in water flux in the antifouling test in comparison with the β-CD/PES membrane. More interestingly, the trans azo groups in azobenzene labeled zwitterions can turn into the cis isomers as the visible light irradiation converted to the UV light irradiation, breaking the interaction between azobenzene labeled zwitterions and β-CD. Hence, the contaminants upon the membrane surface can be simply eliminated by water washing under UV light irradiation. The antifouling membrane can be regenerated via immersing the reacquired β-CD/PES membrane into fresh azobenzene labeled zwitterions solution again.