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Organic solvent nanofiltration (OSN) is an emerging technology for the separation of organic solvents that are relevant to the petrochemical, pharmaceutical, food and fine chemical industries. The separation performance of OSN membranes has continued to push the boundary up through advanced membrane fabrication techniques and novel materials for fabricating the membranes. Despite the many advantages, OSN membranes still face such challenges as low solvent permeability and durability in harsh organic solvent conditions. To overcome these limitations, attempts have been made to incorporate nanomaterial fillers into OSN membranes to improve their overall performance. This review analyzes the potential and use of nanomaterials for OSN membranes, including covalent organic frameworks (COFs), metal-organic frameworks (MOFs), metal oxides (MOs) and carbon-based materials (CBMs). Recent advances in the state-of-the-art nano-based OSN membranes, in the form of thin-film nanocomposite (TFN) membranes and mixed matrix membranes (MMMs), are reviewed. Moreover, the separation mechanisms of OSN with nano-based membranes are discussed. The challenges faced by these OSN membranes are also elaborated, and recommendations for further research in this field are provided., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Thin-film composite (TFC) nanofiltration (NF) and reverse osmosis (RO) membranes have been widely used to remove pharmaceutically active compounds (PhACs) from water and wastewater. However, limited information is available to present the rejection of neutral PhACs under complex water matrices. In this study, we used acetaminophen (AAP) as a representative neutral pollutant to study the effects of feedwater matrices on the rejection of neutral PhACs by NF and RO membranes. The results showed that the permeation of solutes and water through NF and RO membranes followed the classical solution-diffusion model. The corresponding permeability coefficients of AAP for the RO membrane showed good consistency, with average values ranging between (6.19-7.56) × 10 -6  μm s -1 in fresh and brackish feedwater. Meanwhile, the NF membrane exhibited stable AAP and NaCl fluxes as the applied pressure increased from 4.8 to 7.6 bar, suggesting an insignificant influence of convection on solute transport. In addition, a 10-fold increase in NaCl concentration reduced the average AAP permeability coefficient of the NF membrane by 57% (i.e. from 2.8 × 10 -5  m s -1 to 1.2 × 10 -5  m s -1 ), highlighting the relevance of co-existing ions to AAP transport. Furthermore, organic fouling resulted in enhanced AAP rejection by both NF and RO membranes at neutral pH level and medium applied pressure (i.e. 5.8 bar). Overall, this study provided important insights into the separation mechanism of TFC membranes for neutral PhACs, as well as the complex effects of the water matrix on the solute permeation processes., (Copyright © 2022 Elsevier Ltd. All rights reserved.)