Nanocomposite membranes embedded with functionalized MoS2 nanosheets for enhanced interfacial compatibility and nanofiltration performance

Two-dimensional (2D) nanosheets have attracted extensive attention and have been considered as compelling nanofillers of polyamide-based nanofiltration membranes (NFMs) with thin film nanocomposite (TFN) frame. However, there still remains a big challenge, the poor compatibility between these 2D nanofillers and the polyamide matrix, significantly restricting their practical applications. Herein, we present TFN NFMs by incorporating tannic acid (TA) functionalized molybdenum disulfide (MoS2) nanosheets into the polyamide skin layers via typical interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC). TA was employed to assist the aqueous exfoliation of bulk MoS2 into 2D nanosheets, and simultaneously served as the functional molecule to modify and stabilize the as-exfoliated MoS2 nanosheets in aqueous solutions. Thanks to the contribution of TA, the MoS2 nanosheets can be covalently linked into the skin layers through the reaction of TA and TMC, thus exhibiting excellent compatibility with polyamide matrix. Besides, the as-prepared TFN NFMs show promoted water permeation as high as 17.0 L/m(2).h.bar without compromising the salt rejection of divalent ions (98.5%). Moreover, these high-performance TFN NFMs also possess outstanding long-term stability, with great implication for the practical applications.