Surface engineering for ultrapermeable antibacterial conjugated microporous polymer-polyamide composite membranes

Water permeability and ion sieving ability are the main indicators that determine the separation performance of nanofiltration membranes. Enlarging surface areas of permeable separation layers is an effective pathway to facilitate water flux while maintaining salt retention. Inspired by the condensation and cross-linking of amino groups/imines with acid chlorides to form dense polyamide networks, we proposed a strategy to enlarge separation surface areas of nanofiltration membranes by grafting highly porous porphyrin-aniline conjugated microporous polymers (PACMP) onto polyamide. Upon forming CMP-polyamide composite membranes via one-step interfacial polymerization, an ultra-permeable composite membrane (61.8 L m−2 h−1) was fabricated, with salt (Na2SO4) rejection rate above 91.6%. Besides, thanks to the reactive oxygen species produced by porphyrin groups of PACMPs, the in situ generated photoexcited singlet oxygen (1O2) can kill 98.5% of Escherichia coli and 99.7% of Staphylococcus aureus, imparting excellent antibacterial properties to the CMP-polyamide composite membranes.