A robust peroxymonosulfate activator for tetracycline degradation: Mitigating deactivation via stitching N-doped carbon nanotubes with encapsulated Co nanoparticles in bubble-like architectures

Peroxymonosulfate (PMS)-based advanced oxidation techniques provide feasible solutions to mitigate antibiotic contaminants, whereas conventional Co-based materials suffer from deactivation because of structural instability, serious metal leaching and inorganic/organic species poisoning. Herein, we propose a concept by constructing bubble-like architectures stitched by N-doped carbon nanotubes with encapsulated small Co nanoparticles ([email protected]) to boost the deactivation resistance for tetracycline hydrochloride (TCH) degradation via PMS activation. This concept is performed through a NCNTs encapsulating and self-assembly strategy via a simple one-step pyrolysis using cobalt nitrate as metal source and imidazole as carbon/nitrogen sources and foaming agent. The optimal [email protected] exhibits a good catalytic activity with a removal efficiency of 93.1 % and a rate constant of 0.123 min−1 at 25 °C for TCH degradation via PMS activation. The catalyst can be easily isolated by an external magnet and reused for five times without obvious activity loss, indicating its excellent recycling stability. Radical quenching and electron paramagnetic resonance tests unveil the dominant non-radical pathway for TCH degradation with the [email protected]/PMS system. The possible degradation pathways for TCH with the system are proposed. This study offers a feasible way to fabricate PMS activator for TCH removal with exceptional stability.