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 (─SO 3 H) 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 , while maintaining an exceptional water permeability (), significantly outperforming single‐functionalized counterparts. Mechanistic studies reveal that ─COOH domains drive the hydration‐assisted interfacial enrichment of tritiated water (HTO), whereas ─SO 3 H 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.