Oriented Singlet Oxygen Generation via Molecular Oxygen Activation on O-Doped FeS₂ for the Robust Antibiotics Remediation

The widespread occurrence of antibiotics in the natural aquatic environment requires urgent remediation. The promising oxidation processes typically generate hydroxyl radicals (·OH) with the addition of chemical oxidants; however, they suffer from limited removal efficacy due to excessively undesired depletion of ·OH by coexisting environmental substances. Hence, this study proposed to address the above challenges by the oriented generation of singlet oxygen (1O2) from oxygen molecules (O2). Guided by DFT calculation, the adsorption capacity and subsequential activation of O2 were promoted through doping O on FeS2 (FeS2-O), leading to the oriented production of 1O2 with a 46.87-fold higher exposure than ·OH, with visible-light irradiation-trigged photogenerated electrons to facilitate the activation process. The FeS2-O/O2 system exhibited a remarkedly enhanced remediation efficiency of antibiotics, with a 6.62-fold increase in kinetic constant compared to pristine FeS2. In addition, 1O2-mediated antibiotic remediation demonstrated robust performance across various water qualities, with a great potential to reduce ecotoxicological risks. We developed an external oxidant-free technique for the directed production of 1O2 from O2 to effectively degrade and detoxify antibiotics in aquatic environments, providing new insights for natural water remediation.