Interfacial flow-kinetics coupling enables nanofiltration with decoupled antibiotic rejection and salt permeation in high-salinity wastewater.

Efficient separation of antibiotics from high-salinity water matrices, such as fermentation broths and pharmaceutical wastewater, remains a critical challenge for both resource recovery and environmental risk mitigation. Conventional nanofiltration (NF) membranes often suffer from an intrinsic trade-off between antibiotic rejection and salt permeability, leading to excessive salt retention and limited applicability under high-ionic-strength conditions. Herein, we report a dynamically regulated NF membrane fabricated via kinetically controlled interfacial polymerization to decouple antibiotic retention from salt exclusion. By introducing 1,3,5-triaminotoluene (TAT) as a kinetic regulator into a conventional piperazine/trimesoyl chloride system, the packing density of the polyamide network is precisely tuned, enabling a "loose yet robust" selective layer that simultaneously maintains near-complete antibiotic rejection and facilitates rapid salt permeation. The incorporation of TAT induces pronounced interfacial tension gradients, triggering Marangoni convection that drives interfacial instabilities and gives rise to a distinctive crater-like surface morphology. This flow-induced structural evolution enlarges the effective filtration area and concurrently tailors the polyamide microstructure, producing a free-volume-enriched selective layer with a balanced crosslinking density. As a result, the optimized membrane exhibits high water permeance (22.0 L·m⁻²·h⁻¹·bar⁻¹), near-complete rejection of antibiotic molecules, and markedly suppressed NaCl rejection, yielding an exceptional antibiotic/salt separation factor of 96.1. The membrane further demonstrates robust and generalizable separation multiple antibiotics, excellent antifouling behavior, and stable long-term performance under high-salinity conditions representative of industrial fermentation wastewater. This study highlights an interfacial flow-kinetics coupling paradigm and provides a scalable strategy for efficient antibiotic desalination and sustainable resource recovery.