Heterogeneous Activation of Peroxymonosulfate by NiCo-LDH for the Non-radical Dominated Degradation of Sulfamethoxazole

Peroxymonosulfate(PMS)-based advanced oxidation process has demonstrated significant potential for the remediation of emerging organic contaminants in water. In this study, a sea urchin-like nickel-cobalt double hydroxide (Ni 1 Co 2 -LDH) catalyst was developed and exhibited superior performance and robust durability in PMS activation. The system achieved 99.28% removal of sulfamethoxazole (SMX) within 60   minutes, with a reaction rate constant of 0.1393   min −1 , and also exhibits broad applicability for degrading various representative organic pollutants. Radical quenching experiments and electron paramagnetic resonance spectroscopy identified singlet oxygen ( 1 O 2 ) as the predominant reactive species responsible for SMX degradation, followed by hydroxyl and sulfate radicals. Density functional theory calculations further revealed the critical role of oxygen molecules in both PMS activation via electron transfer and the generation of O •− 2 , a key precursor to 1 O 2 . The singlet oxygen exhibited high selectivity in degrading SMX through 1,2-addition reaction pathways. This study highlights the role of oxygen in PMS activation and provides valuable insights for addressing the challenge of persistent organic pollutants in complex aquatic environments.