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Designing a stable and uniform hydrophilic material for separation of oil and water is strongly desired for sustainable management of oily wastewater. Herein, a stable and uniform bio-inspired coating onto the non-woven fabric substrate with superhydrophilicity and underwater superoleophobicity via rapid co-deposition of dopamine and polyethylenimine was demonstrated. Ammonium persulfate outperformed other oxidants (e.g., Cu2+-H 2 O 2 and NaIO 4) to rapidly trigger the co-deposition of dopamine and polyethylenimine for homogeneous superhydrophilic and underwater superoleophobic surface engineering. Furthermore, the co-deposition conditions, i.e., concentration of ammonium persulfate and exposure duration, have a positive dependence on the hydrophilicity and underwater oleophobicity of the coated fabric membranes. Specifically, the superhydrophilicity and underwater superoleophobicity (underwater oil contact angle of 165.4 ± 1.1°, sliding angle of 2.5 ± 0.5°) can be obtained for the coated fabric membranes at the optimal co-deposition condition (i.e., 28.5 mmol L−1 persulfate and coating duration of 7 h), showing a great potential in gravitational oil-water separation (permeation flux >115,000 L m−2 h−1; oil rejection >99.2%). Integrating with a superhydrophobic copper mesh, the oil-water mixed solution can be continuously and sufficiently separated, realizing simultaneous recovery of pure oil and water from oily wastewater. In addition, the bio-inspired coating displays a strong long-term chemical robustness and stability in extreme environments (i.e., acidic/alkaline solutions and oils). The study provides a facile, cost-effective and practical strategy in constructing superhydrophilic and underwater superoleophobic interfaces for sustainable treatment of oily wastewater. Image 1 • Mussel-inspired coating endows non-woven fabric membranes with robust superhydrophilic interface. • Persulfate have an impressive efficacy to rapidly trigger the mussel-inspired coating. • The mussel-inspired coating yields an underwater oil contact angle of 165.4 ± 1.1°. • The superhydrophilic fabric membrane has a permeation flux of >115000 L m−2 h−1 with >99.2% oil rejection. • Integrating bio-inspired fabric membrane with superhydrophobic copper mesh can continuously recover oil and water. [ABSTRACT FROM AUTHOR]

• Tight UF membrane with 1700 Da MWCO was designed by rapid co-deposition of PDA/PEI triggered by APS. • Tight UF membrane had an impressive rejection of >98.2% for 6 reactive dyes with >97.0% salt permeation. • Integrated UF-diafiltration enriched reactive blue 4 from 2.04 to 50.70 g·L−1 with 0.9% dye loss. • 99.95% salt removal was obtained by integrated UF-diafiltration with 8 diavolumes. • Tight UF membrane yielded a 90.6% flux recovery by water rinsing, showing a low fouling propensity. Mussel-inspired polydopamine (PDA) coating has received increasing interest in membrane modification for versatile liquid filtration applications, due to its intrinsic adhesion nature. Nevertheless, the bio-inspired PDA deposition initiated by air-oxidation is time-consuming process and generally results in an uneven and unstable coating, which compromises the membrane filtration performance. In this study, the PDA/polyethylenimine (PEI) co-deposition triggered by ammonium persulfate (APS) was conducted to fabricate the tight ultrafiltration (t-UF) membranes with 1000–5000 Da molecular weight cut-offs (MWCOs) for sustainable treatment of highly-saline textile wastewater. APS with strong oxidation capacity can rapidly induce the co-deposition of PDA/PEI layer onto hydrolyzed polyacrylonitrile (HPAN) substrate through the Michael addition or Schiff base reactions, simultaneously minimizing the covalent polymerization of dopamine for PDA aggregation. With 1.5-h coating, a smooth, compact and defect-free PDA/PEI layer with 1700 Da MWCO was evolved on the HPAN substrate, evincing a >98.2% retention for various reactive dyes (610–1000 Da molecular weights) with >97.0% permeation of inorganic salts. In addition, an integrated UF-diafiltration procedure was applied to fractionate the reactive blue 4 (RB4)/NaCl and RB4/Na 2 SO 4 mixtures, enriching the RB4 dye from ca. 2.04 to 50.70 g·L−1 with ca. 99.95% desalination efficiency and ca. 99.2% dye recovery. These results demonstrate that the bio-inspired t-UF membrane through fast PDA/PEI co-deposition is of great promise to sufficiently fractionate the dyes and salts for dye desalination and recovery, realizing the sustainable management of highly-saline textile wastewater. [ABSTRACT FROM AUTHOR]