Boronate ester-based pH stimulated bactericide armoring for efficient fouling control of LNF membranes

Membrane fabricated with a method of ingenious simplicity to be equipped with antibacterial function is the key to address the biofouling issue in separation applications. Herein, we proposed an innovative approach to armor abundant antibiotics on the membrane with minimal loss of the active functional groups of the antibiotics. Boronate ester-based membrane was first fabricated with non-solvent induced phase separation (NIPS) method. A loose nanofiltration (LNF) membrane with unique trinity structure was then constructed through the cross-linking between boronate ester complexes and trimesoyl chloride (TMC) on the top layer. Due to the pH responsive and dynamic nature of boronate ester complexes, boronic acid groups can be released under acidic conditions, acting as binding sites for diol-bearing antibiotics. This not only allows the sufficient anchoring of antibiotics (here kanamycin (KM) was chosen as model antibiotics), but also minimizes the consumption of active groups of KM molecules. The resultant membrane delivers excellent biocidal effect against both Gram-negative and positive bacteria, while also exhibiting superior water permeance of 134.86 ± 5.62 L m−2 h−1 bar−1. This work reveals the great potential of boronate esters complexes for the development of high-flux antibacterial membranes.