Construction of water molecular transport channel by ortho-hydroxyazo-linked framework material for enhanced nanofiltration performance and anti-bacterial properties

Abstract

Membrane technology has been being widely employed in wastewater treatment in recent years. Developing high-permeability and high-selectivity separation membrane is a key to expand their applications. In practice, biofouling often has a negative effect on membrane performance and membrane life span. Therefore, it is urgently needed to develop novel high-performance separation membrane with fast water molecular transport channel and excellent anti-bacterial properties. Owing to the abundant water molecular transport provided by ortho-hydroxyazo-linked porous organic polymer (o-POP) with polar functional groups and high hydrophilicity, and the excellent anti-bacteria and abundant oxygen-containing functional groups of graphene oxide (GO) material, high stable o-POP/GO composite membrane with abundant transport channel was constructed on a nylon substrate via simple in situ method in this work. The synergistic effect of o-POP and GO effectively improved the ability of water transport and anti-bacteria performance of the composite membrane. The o-POP/GO composite membrane not only possessed high water permeability of 151.3 L m^–2 h⁻¹ bar⁻¹ and excellent dye rejection (Evans blue (EB): 96.3 %, Methyl blue (MB): 98.0 %, Congo red (CR): 99.0 %, Eriochrome black T (EBT): 97.3 %, Methyl orange (MO): 71.5 %), but also exhibited positive anti-bacterial effect for Escherichia coli.