Thin-film nanofibrous composite (TFNC) membranes, containing a multi-layered structure, for nanofiltration (NF) were demonstrated. The best performing membranes consisted of a three-layered structure, including the poly(ethylene terephthalate) (PET) non-woven support, polyacrylonitrile (PAN) electrospun mid-layer, and composite barrier layer based on cellulose nanofibers (CN) and polyamide (PA) matrix made by interfacial polymerization. Under the chosen test conditions (482 kPa, 2000 ppm MgSO4 as the feed solution), all manually coated TFNC-NF membranes exhibited high rejections (above 99%), where the best membrane showed a flux of 44.7 L/m(2) h (LMH), significantly higher than that of the membrane prepared by the conventional phase-inversion substrate (its flux was 27.6 LMH). Transmission electron microscopy (TEM) indicated that the CN component embedded in the PA matrix probably introduced directed water channels, thus increasing the permeability of the barrier layer. The machine-driven slot-die coating method was applied to improve the membrane performance by reducing the barrier layer thickness through regulating the organic solution delivery in interfacial polymerization. With the optimized organic solution delivery, the membranes exhibited a flux of 71.7 LMH and a rejection of 98.5%, which were better than those of a commercial NF membrane (DOW Filmtec NF 270) having similar barrier layer chemical compositions. The flux of the slot-die coated TFNC-NF membrane was further improved by using 20 wt% bipiperidine (BP) with respect to the total amine monomers for interfacial polymerization, where the membrane exhibited a flux of 94.3 LMH (i.e., doubling the flux of NF 270) and a rejection of 96.7% (the rejection of NF 270) was 97%). (C) 2014 Elsevier B.V. All rights reserved.