Leaching-resistant armor nano-cobalt embedded biochar for efficient removal of sulfamethoxazole and microcystin-LR via PMS activation

Environmentally remediation demands sustainable catalytic solutions that combine high efficiency with low environmental impact. This study presents a novel strategy for preparing a composite of N-doped carbon layer-encapsulated armor Co nanoparticles supported on coffee grounds-based biochar (ArmCo-C) as an eco-friendly Fenton-like catalyst. This innovative catalyst effectively activates peroxymonosulfate (PMS) to achieve exceptional removal efficiencies of 99.5% for the persistent organic pollutant (POP) sulfamethoxazole (SMX) and 99.2% of the hepatotoxic cyclic structural heptapeptide microcystin-LR (MC-LR) under optimized conditions. Through electron paramagnetic resonance and radical capture experiments, we elucidate the degradation mechanisms, revealing that nonradical degradation via singlet oxygen ( 1 O 2 ) dominates the SMX degradation process. Furthermore, we speculate a potential degradation pathway for MC-LR based on the LC-MS-identified intermediates, providing molecular-level insights into cyclic peptide breakdown. The proposed Co-based armor catalyst provides valuable insights into advanced oxidation technologies and the upcycling of solid waste. • The AmoCo-C/PMS system decomposes toxic microcystin-LR (99.2%) in 30 min. • The catalysis system can easily remove antibiotic SMX (99.5%) in 20 min. • Armor Co NPs supply radical sites; N-doped defective biochar offers non-radical ones. • 1 O 2 is the main substance in the catalytic system with a dual non-radical pathway.