Confinement-Amplified Tritiated Water Clean-Up in Functionalized Graphene Oxide Nanochannels.

Tritium separation from aqueous effluents is notoriously difficult due to the nearly identical physicochemical properties of tritiated and light water. Herein, we present a chemically programmable, dual-functional graphene oxide (GO) membrane for highly selective tritium removal under ambient conditions. By interfacially co-assembling carboxyl- (─COOH) and sulfonic acid-functionalized (─SO3H) GO, a mixed membrane (MIX) was constructed to synergistically regulate interfacial chemistry and nanoconfined transport. The MIX membrane delivers a single-pass tritium removal efficiency exceeding 21% and a separation factor > 1.2 , while maintaining an exceptional water permeability ( > 13 L m - 2 h - 1 bar - 1 ), significantly outperforming single-functionalized counterparts. Mechanistic studies reveal that ─COOH domains drive the hydration-assisted interfacial enrichment of tritiated water (HTO), whereas ─SO3H sites provide strong adsorption stabilization to facilitate reversible isotope exchange. Furthermore, operation-induced interlayer expansion maximizes active site accessibility. This work demonstrates a cooperative strategy integrating interfacial chemistry and nanoconfinement engineering in 2D membranes, offering a low-energy, high-throughput platform for the remediation of tritiated radioactive wastewater.