Thermal-intensified interfacial polymerization enables ultra-selective reverse osmosis membrane for toxic micropollutant removal.

Polyamide reverse osmosis (RO) membranes are widely used in seawater desalination and wastewater reuse, yet often fail to remove small toxic micropollutants. Herein, we develop a thermal-intensified interfacial polymerization (TIP) strategy to fabricate highly selective RO membranes against various micropollutants. Facile heating accelerates amine monomer diffusion, intensifying interfacial polymerization to form a highly crosslinked polyamide membrane. The resultant TIP membrane achieves rejection of 90.8%, 98.0%, and > 99% for boron, arsenite, organic micropollutants at neutral pH, respectively. Meanwhile, high temperature facilitates interfacial degassing and promotes the formation of more extensive nanovoids within the polyamide. These nanovoids increase membrane surface area and optimize water transport pathways, thereby boosting water permeance. The combination of high solute rejection and water permeance enables the membrane to achieve high water-micropollutant selectivity (e.g., water-boron). Our study demonstrates that TIP technique holds a great promise to fabricate ultra-selective polyamide membranes for desalination and wastewater reuse.