Interface synthesis of flexible benzimidazole-linked polymer molecular-sieving membranes with superior antimicrobial activity

Abstract

Benzimidazole-linked polymers (BILPs) are a type of porous organic frameworks (POFs) that possess high microporosity, exceptional thermal and chemical stabilities. Uniform growth of BILP-101x layer (∼95 nm) directly on the hydrolyzed polyacrylonitrile (HPAN) substrate can be realized within 30 min. The microstructure and separation capability of BILPs membranes were feasibly regulated by the precise control of synthetic parameters. Molecular simulations were performed to reveal the inner structure and molecular transportation behavior of the BILPs membranes. The optimized composite membrane exhibits ultra-high water permeance (∼255 L m −2 h −1 bar −1 ) with extraordinarily high dye/divalent salt selectivity, e.g., Congo red (696.7 Da), Direct red 23 (814 Da) > 99.0%, Na 2 SO 4 < 9%. Furthermore, the resultant membranes evince distinct antimicrobial activity due to the abundant benzimidazole groups in the polymer networks, and the colonies of live Escherichia coli ( E. coli ) bacteria were drastically reduced by 98.4%. Therefore, the resultant BILP membranes which exhibit remarkable permselectivity and superior antimicrobial properties are promising candidate for many applications such as dye desalination and water purification. Facile manufacture of flexible BILP membrane for efficient dye/divalent salt separation with ultrahigh water permeability and superior antimicrobial properties. • Thin and flexible BILP membrane was synthesized on top of PAN substrate. • The microstructure and separation performance of BILP membrane have been explored. • The BILP membrane exhibits ultra-high water permeance and dye/salt selectivity. • Abundant benzimidazole groups endow the membrane superior antimicrobial properties.