Bimetallic synergy-driven generation of high-valent metal-oxo species in a nanoconfined catalytic ceramic membrane for efficient antibiotic-containing water treatment.

Efficient purification in complex waters requires catalytic membranes with high selectivity and interference resistance, a need addressed by nanoconfinement through steering reactive species toward nonradical oxidation. Herein, a cobalt-nickel layered double hydroxide (CoNi-LDH) catalyst was synthesized via hydrothermal conversion of a CoNi metal-organic framework self-sacrificing template and deposited onto a ceramic substrate. In a continuous flow-through system with peroxymonosulfate (PMS), the membrane achieved 97.6% sulfadiazine degradation. The nanoconfined effect increased the pseudo-first-order reaction rate constant of sulfadiazine degradation to 4.916 s-1, three orders of magnitude higher than that of conventional batch system (2.433 × 10-3 s-1). Mechanistic investigation showed that the O-O bond heterolysis of PMS generated high-valent cobalt-oxygen species as the dominant reactive species, endowing high resistance and oxidation selectivity. The degradation efficiencies exceeding 95% for various organic micropollutants and performed stably in actual surface water and secondary effluent. It also exhibited permeate flux recovery efficiency exceeding 80% after multiple cycles of cleaning and fouling caused by humic acid, indicating excellent antifouling properties. This work provides a theoretical foundation and instructive demonstration for nonradical catalytic membrane reactors toward practical water treatment.