Thin-film nanocomposite nanofiltration membrane with an ultrathin polyamide/UIO-66-NH2 active layer for high-performance desalination

In this work, ultrasmall metal-organic frameworks (MOFs) nanoparticles, UIO-66-NH2 nanoparticles were synthesized and embedded in an ultrathin polyamide (PA) active layer via the interfacial polymerization reaction on a polydopamine-wrapped single-walled carbon nanotube film. A thin-film nanocomposite nanofiltration (TFN NF) membrane with a PA/UIO-66-NH2 active layer as thin as 20 ± 3 nm was thus fabricated. The loading mass of the nanoparticles in the TFN NF membrane could be tuned by controlling the nanoparticles concentration in aqueous phase. Benefiting from the ultrathin thickness of active layer and the high loading mass of the MOFs nanoparticles, water permeability up to 46 L m−2 h−1 bar−1 along with a Na2SO4 rejection of 97.1% was achieved, which is 53% increase of the TFC NF membrane without the addition of UIO-66-NH2 nanoparticles. Our membrane owns the thinnest active layer in the category of TFN NF membranes reported so far and exhibits outstanding desalination performance.