Millisecond-scale water decontamination enabled by nanoconfined single-atom catalytic membranes.

The imperative for sustainable water infrastructure demands highly intensified decontamination technologies that transcend current kinetic and efficiency limits. While peroxymonosulfate (PMS)-based advanced oxidation processes hold great promise for degrading refractory organic pollutants, their practical application is constrained by excessive oxidant dosage and large reactor footprints stemming from inherent mass-transfer restrictions and inefficient oxidant utilization. Herein, we report an atomically engineered nanoconfined catalytic membrane (AENCM) incorporating a phosphorus-doped iron single-atom catalyst, which synergistically integrates nanoconfinement with convective mass transfer to enable ultrafast, highly resource-efficient water decontamination. The elaborately constructed FeN4-P2 configuration precisely modulates the electronic structure of Fe active centers, enhancing PMS adsorption and driving dual non-radical oxidation pathways. Under flow-through filtration, nanoconfinement cooperates with convective mass transfer to effectively elevate local reactant concentrations, compress the diffusion boundary layer, and minimize reactive species quenching. Consequently, the AENCM achieves >97% removal of bisphenol A within a hydraulic retention time of 32 ms. This system delivers a remarkable normalized apparent rate constant of 1.91 × 106 μMBPA mM-1PMS min-1, surpassing those of reference systems by 1-5 orders of magnitude. Furthermore, the AENCM maintains >99% removal for multiple contaminants over 120 h of continuous operation in real municipal secondary effluent, with negligible iron leaching (<0.02 mg L-1). This work establishes a multiscale strategy to overcome mass-transfer barriers and maximize PMS utilization in single-atom catalysis, offering a practical engineering pathway toward ultra-centralized and efficient urban and industrial water treatment facilities.