MoS2 @PDA thin-film nanocomposite nanofiltration membrane for simultaneously improved permeability and selectivity

Recent studies have documented that the incorporation of nanomaterials can effectively enhance the permselectivity of thin-film composite (TFC) membrane. The distribution and compatibility of molybdenum disulfide (MoS 2 ) nanosheets lack of functional groups within polymer matrices are research hotspots. Here we present polydopamine (PDA) modified MoS 2 (MoS 2 @PDA) nanosheets as nanofillers to prepare thin-film nanocomposite (TFN) nanofiltration (NF) membrane. PDA not only enhanced the dispersion and compatibility of MoS 2 in the polyamide matrices, but also resulted in defect-free TFN membranes due to its self-polymerization. The obtained TFN membrane loaded with 0.01 wt% MoS 2 @PDA nanosheets (TFN-0.01) had water permeability of 6.7 L m −2 h −1 bar −1 , 1.45 times of the TFC membrane. The Na 2 SO 4 rejection increased from 97.1% to 98.2%, thus overcoming the long-standing permeability-selectivity trade-off of desalination membranes. Moreover, TFN-0.01 NF membrane had excellent long-term stability. Our results showed that PDA can effectively solve the dispersibility and compatibility problems of nanofillers in polymer matrices, especially for the nanofillers lack of functional groups. • PDA generates molecular bridge between nanofillers and polymer matrices. • PDA enhances the dispersibility and compatibility of MoS 2 in PA matrices. • The obtained TFN-0.01 membrane showed 45% flux improvement with Na 2 SO 4 rejection of 98.2%.