Enhancing the Permselectivity of Thin-Film Composite Membranes Interlayered with MoS 2 Nanosheets via Precise Thickness Control.

The demand for highly permeable and selective thin-film composite (TFC) nanofiltration membranes, which are essential for seawater and brackish water softening and resource recovery, is growing rapidly. However, improving and tuning membrane permeability and selectivity simultaneously remain highly challenging owing to the lack of thickness control in polyamide films. In this study, we fabricated a high-performance interlayered TFC membrane through classical interfacial polymerization on a MoS 2 -coated polyethersulfone substrate. Due to the enhanced confinement effect on the interface degassing and the improved adsorption of the amine monomer by the MoS 2 interlayer, the MoS 2 -interlayered TFC membrane exhibited enhanced roughness and crosslinking. Compared to the control TFC membrane, MoS 2 -interlayered TFC membranes have a thinner polyamide layer, with thickness ranging from 60 to 85 nm, which can be tuned by altering the MoS 2 interlayer thickness. A multilayer permeation model was developed to delineate and analyze the transport resistance and permeability of the MoS 2 interlayer and polyamide film through the regression of experimental data. The optimized MoS 2 -interlayered TFC membrane (0.3-inter) had a 96.8% Na 2 SO 4 rejection combined with an excellent permeability of 15.9 L m -2 h -1 bar -1 (LMH/bar), approximately 2.4 times that of the control membrane (6.6 LMH/bar). This research provides a feasible strategy for the rational design of tunable, high-performance NF membranes for environmental applications.