CoFeMn layered double hydroxide-based nanoconfined gravity-driven catalytic membrane for efficient water decontamination: Performance and mechanistic insight

Heterogeneous Fenton-like catalysis using peroxymonosulfate (PMS) faces significant challenges in pollutant removal due to mass transfer limitation and inefficient reactive oxygen species generation. To address these issues, a novel trimetallic (CoFeMn) layered double hydroxide (LDH) membrane was fabricated, integrating nanoconfined catalysis with membrane filtration. This CoFeMn LDH membrane/PMS system achieved complete ranitidine degradation, with a first order rate constant of 4 ms⁻¹, while maintaining a stable gravity-driven permeate flux of 21 LMH. Notably, this performance surpasses the batch-scale system by exhibiting 2.79 × 10⁵ times higher rate constant and outperforms state-of-the-art catalytic membranes by 1–4.5 orders of magnitude. Density functional theory calculations revealed a high PMS adsorption energy on the CoFeMn LDH membrane (E_ads = −3.84 eV), indicating superior chemisorption, and confirmed rapid charge transfer mechanism with electron transfer from CoFeMn LDH to PMS (1.014 e). Furthermore, nanoconfinement within the CoFeMn LDH membrane nanochannels significantly enhanced the degradation of pharmaceuticals and endocrine-disrupting chemicals, providing stable performance for 100 h continuous operation. This study demonstrates the potential of trimetallic LDH-based catalytic membranes for sustainable and efficient water purification.