Enhanced photocatalytic degradation of sulfamethoxazole using MIL-101(Fe) supported Mo single-atom with oxygen vacancies under visible light activation of peroxymonosulfate

This study investigates the degradation of sulfamethoxazole (SMX), a widely detected and persistent antibiotic in the environment, using a novel photocatalytic system based on MIL-101(Fe) supported Mo single-atom with oxygen vacancies (Mo/Ov-MOF). Anchoring Mo single-atoms into the MOF structure enhances catalytic activity by effectively improving charge separation and reducing electron-hole recombination. The Mo/Ov-MOF efficiently activates peroxymonosulfate (PMS) under visible light, generating singlet oxygen ( 1 O 2 ) as a primary reactive species responsible for SMX degradation. Degradation experiments demonstrated that the degradation efficiency reached 96.8 % in the presence of PMS and visible light. Through quenching and trapping experiments on active species, an in-depth investigation into the source of 1 O 2 was performed, demonstrating the crucial role of holes in the rapid and selective generation of 1 O 2 under visible light. Additionally, the reusability of the Mo/Ov-MOF catalyst was confirmed, maintaining over 70 % degradation efficiency after five cycles. Toxicity assessments indicated that the degradation by-products exhibited significantly lower toxicity than the parent compound SMX, thus mitigating potential ecological risks. The mechanistic insights reveal that oxygen vacancies and Mo single-atom enhance electron transport and facilitate efficient PMS activation, ultimately leading to effective pollutant degradation. The findings underscore the potential of the Mo/Ov-MOF photocatalytic system for practical applications in wastewater treatment, particularly for removing persistent organic pollutants from aquatic environments.