Two birds with one stone: by-product HCl consumption and in-situ template formation for high-performance nanofiltration membranes fabrication

Nanofiltration (NF) membrane with good permselectivity is highly desired. However, it often suffers from permeability-selectivity trade-off in practical applications. To overcome this challenge, a novel in-situ template strategy was proposed for the preparation of high-performance thin film nanocomposite (TFN) NF membrane by adding AgNO3 in the aqueous solution. The AgCl nanoparticles can be in-situ incorporated into the polyamide film due to the by-product of HCl from the interfacial polymerization and AgNO3 at the oil/water interface. Besides, water transportation channels can be further constructed in the polyamide film via removal the AgCl template using ammonia as post-treatment solution. The optimized NF-3 membrane with low water transportation resistance shows a two-fold permeance as well as equal salt rejection compared with the controlled NF-1 membrane, indicating that the “trade-off” effect is effectively inhibited. Consequently, the in-situ template strategy provides a new sight for the preparation of high-performance NF membrane.