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The scarcity of water resources has led to widespread interest in the treatment of oily wastewater. This study prepared a novel superhydrophilic/underwater superoleophobic polysulfonamide (PSA)/polyvinylpyrrolidone (PVP) nanofibrous membrane through electrostatic spinning for efficient oil−water emulsion separation. The surface morphology, fiber diameter distribution, wettability properties, and oil−water emulsion separation performance of the membranes were investigated. Results showed that the addition of PVP increases the diameter of the fibers, which led to a loose, large, porous structure and improved the permeability of the membranes. A high pure-water flux of 2057 L•m −2 •h −1 was obtained for membranes with PVP addition of 3 wt%, providing an 835% increase in pure-water flux compared with a pure PSA nanofibrous membrane (220 L•m −2 •h −1 ). For nhexane-in-water emulsions, the optimum membrane obtained a high separation efficiency of 99.7%, in which flux was 1.5 times greater than that of the pure PSA nanofibrous membrane. Moreover, the optimum membrane exhibited good recycling stability and solvent resistance. The as-prepared PSA/PVP nanofibrous membrane displayed high permeability, an outstanding rejection rate, resistance to organic solvents, and reusability for oil−water separation, providing great potential in practical membrane separation applications.

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Fabrication of high-dye/salt-separation-performances and chlorine-resistant nanofiltration (NF) membranes are crucial for dye desalination. In this study, a thin-film composite NF membrane (PES–DPS) was prepared through the interfacial polymerization of 3,3′-diaminodiphenyl sulfone (DPS) and trimesoyl chloride. Because of the low reactivity and the presence of the sulfone group (O=S=O) of DPS, the prepared PES–DPS membrane provided a relatively loose polyamide layer and exhibited excellent chlorine resistance, enhancing the membrane water flux and dye/salt separation performances. Furthermore, the influence of DPS concentration was systematically investigated. The optimal membrane PES–DPS–1 exhibited high direct Blue 71 rejection (99.1%) and low NaCl rejection (8.7%). Meanwhile, the PES–DPS–1 membrane displayed highly pure water flux (49.4 L·m−2·h−1·bar−1) even at a low-operating pressure (2 bar). Moreover, no significant difference in dye rejection was observed when the membrane was immersed in NaClO solution (pH = 4.0, 2000 ppm) for 12 h, thereby demonstrating its outstanding chlorine stability. In summary, this work provided a new monomer for the preparation of novel polyamide membranes to achieve excellent separation performances and chlorine resistances.