A photocatalytic system for the Alleviation of ocean acidification and antibiotic pollution

Ocean acidification from the uptake of CO₂ and antibiotic pollution from a consequence of inshore mariculture are two serious threats to marine ecosystems. In this work, a novelty oxygen-doping carbon nitride (O-CN) photocatalyst are designed for the release of CO₂ and degradation of a targeted antibiotic (ofloxacin, OFL) in acidified seawater. Notably, this photocatalytic system can take advantage of ocean acidification as more CO₃^•- radicals were produced in the seawater. The catalyst could degrade OFL rapidly (k = 0.039 min⁻¹) in the presence of CO₃^2– and HCO₃^–, which derive from the dissolved CO₂ in the seawater, much higher than that of pristine CN (k = 0.013 min⁻¹). Mechanism study revealed that the existence of CO₃^2– and HCO₃^– would facilitate the generation of new N-C-O (O1) groups on the O-CN surface. These O1 groups are the active sites for the formation of •OH radicals that can oxidize OFL and release CO₂. This investigation offers a novel strategy for alleviating two environmental threats simultaneously.