Polymerizable viscous additive-assisted interfacial polymerization enables superior micropollutant/mineral selective separation in nanofiltration membranes for sustainable water purification.

Selective removal of hazardous organic micropollutants (OMP) while preserving beneficial mineral ions (e.g., Ca2 + and Mg2+) remains challenging for conventional nanofiltration (NF) membranes, which commonly reject both OMP and mineral salts. Herein, we developed a sulfonated poly(vinyl alcohol)-incorporated nanofiltration (SINF) membrane through a polymerizable viscous additive-assisted interfacial polymerization strategy. By using sulfonated poly(vinyl alcohol) (SPVA) as a multifunctional aqueous-phase additive, the diffusion of piperazine was retarded and additional -SO3H groups were incorporated into the polyamide (PA) layer, creating a thin, loose, and highly negatively charged selective layer with ring-shaped surface topographies and nanovoid-enriched substructures. The optimized SINF membrane achieved an OMP/mineral (eltrombopag/Ca2+) separation factor of 652.0, 41.2 times higher than that of the control membrane, while maintaining a high water permeance of 29.2 L m-2 h-1 bar-1 and an uncompromised Na2SO4 rejection of 98.7%. In real surface water, the SINF membrane also maintained high OMP rejection (≥90.9%) and favorable Ca2+ permeation (65.8%). Enhanced OMP rejection was attributed to strengthened electrostatic exclusion of negatively charged OMP and enhanced hydration layer interaction of hydrophobic OMP. This work provides a robust strategy for designing NF membranes that integrate rapid water transport, strong OMP rejection, and mineral ion preservation for high-quality reclaimed water production.