Advanced oxidation processes (AOPs) using oxygen (O₂) as an oxidant represent a low-cost and sustainable wastewater treatment process. Herein, a metal-free nanotubular carbon nitride photocatalyst (CN NT) was prepared to activate O₂ to degrade organic contaminants. The nanotube structure allowed for sufficient O₂ adsorption, while the optical and photoelectrochemical properties enabled photogenerated charge to be efficiently transferred to the adsorbed O₂ to trigger the activation process. The developed CN NT/Vis-O₂ system based on O₂ aeration degraded various organic contaminants and mineralized 40.7% of chloroquine phosphate within 100 min. In addition, the toxicity and environmental risk of treated contaminants were reduced. Mechanistic studies suggested that the enhanced O₂ adsorption capacity and fast charge transfer behavior on CN NT surface led to reactive·O₂^-, ¹O₂ and h⁺ generation, each of which played a distinct role in contaminants degradation. Importantly, the proposed process could overcome the interference from water matrices and outdoor sunlight, and the energy and chemical reagent savings reduced the operating cost to about 1.63 US$·m⁻³. Altogether, this work provides insights into the potential application of metal-free photocatalysts and green O₂ activation for wastewater treatment.

使用氧气 (O ₂ ) 作为氧化剂的高级氧化工艺 (AOP) 是一种低成本且可持续的废水处理工艺。在此，制备了无金属纳米管状氮化碳光催化剂（CN NT）以激活O ₂以降解有机污染物。纳米管结构允许充分的 O ₂吸附，而光学和光电化学特性使光生电荷能够有效地转移到吸附的 O ₂以触发活化过程。基于O ₂开发的CN NT/Vis-O _2系统曝气可在 100 分钟内降解各种有机污染物并矿化 40.7% 的磷酸氯喹。此外，经处理的污染物的毒性和环境风险也有所降低。机理研究表明，增强的 O ₂吸附能力和 CN NT 表面的快速电荷转移行为导致反应性·O ₂ ^-、¹ O ₂和 h ⁺的产生，其中每一种都在污染物降解中发挥着独特的作用。重要的是，所提出的过程可以克服水基质和室外阳光的干扰，并且节省能源和化学试剂，将运营成本降低至约 1.63 US$·m ⁻³. 总而言之，这项工作为无金属光催化剂和绿色 O ₂活化在废水处理中的潜在应用提供了见解。