Constructing a Co(IV)=O Predominant Catalytic Membrane System via Nanoconfinement of Layered Double Hydroxides for Efficient Bisphenol A Degradation

Peroxymonosulfate (PMS)-based non-radical pathways offer high selectivity and strong anti-interference, yet conventional systems still suffer from active-site aggregation, metal leaching, and limited mass transfer. This study presents a facile strategy for constructing a nanoconfined catalytic membrane by exploiting the "memory effect" of layered double hydroxides (LDHs) to intercalate cobalt species into the interlayers, forming Co-LDH. The resulting Co-LDH membrane exhibits a typical layered structure and enhanced hydrophilicity, along with excellent catalytic performance for BPA degradation when coupled with PMS. Mechanistic studies reveal that the Co-LDH-500 membrane/PMS system proceeds predominantly through a non-radical pathway involving oxygen atom transfer, in which high-valent Co(IV)=O serves as the key reactive species responsible for BPA degradation. In a filtration mode with transmembrane pressure of 0.4 bar and PMS dosage of 0.5 mM, the membrane achieves nearly 100% BPA removal within 30 minutes, with an apparent reaction rate constant of 2.74 s -1 . Furthermore, it demonstrates excellent long-term operational stability, broad pH adaptability, and strong resistance to coexisting ions. This work provides novel insights into the design of highly efficient and stable catalytic membrane systems based on the nanoconfinement effect and high-valent metal-oxo species.