Nanobubbles have gained much attention due to their unusual properties such as large specific surface area, surface energy and internal energy, thereby, increase the surface reaction and improve the mass transfer efficiency. The long term stability of nanobubbles and generation of reactive oxygen species enables them to address various environmental issues for water purification without secondary pollution. However, there are few studies concerning the application of oxygen nanobubbles in the advanced oxidation processes (AOPs). In this study, first time, oxygen nanobubbles were introduced into the photoreaction system under visible light irradiation for enhanced photodegradation of oxytetracycline (OTC). Results indicated that oxygen nanobubbles significantly improved the photodegradation of OTC through high mass transfer and generation of reactive radicals during the nanobubble collapse. The oxygen nanobubble stability was confirmed to be pH dependent. The nanobubbles concentration increased from 0.76 to 3.78×10⁸ particles/mL, while the mean size decreased from 205 nm to 138 nm as the pH value increased (3.2-11.0). The photodegradation efficiency of OTC was improved from 45% to 98% with the increase of pH (4.0-11.0). Oxygen nanobubbles hold promise to improve the AOPs, such as reducing catalysts and chemicals usage and costs. Quenching experiments demonstrated that •OH was the predominant active species induced the photodegradation of OTC. With the development of nanobubbles technology, it is anticipated to realize totally chemicals free green technology. This study provides a novel nanobubble/AOPs technology, which will be more efficient and environmental friendly and will have broad application in waste water treatment and drinking water purification.

纳米气泡由于其不寻常的特性（例如大的比表面积，表面能和内部能）而备受关注，从而增加了表面反应并提高了传质效率。纳米气泡的长期稳定性和活性氧的产生使它们能够解决各种环境问题，从而实现净水而不会造成二次污染。但是，关于氧纳米气泡在高级氧化过程（AOP）中的应用的研究很少。在这项研究中，首次将氧纳米气泡引入可见光辐射下的光反应体系中，以增强土霉素的光降解性能。结果表明，氧纳米气泡通过高质量转移和纳米气泡塌陷期间反应性自由基的产生显着改善了OTC的光降解。氧纳米气泡的稳定性被证实是pH依赖性的。纳米气泡的浓度从0.76增加到3.78×10^8个粒子/ mL，而平均大小随着pH值的增加而从205 nm减小到138 nm（3.2-11.0）。随着pH（4.0-11.0）的增加，OTC的光降解效率从45％提高到98％。氧纳米气泡有望改善AOP，例如减少催化剂，化学品的使用和成本。淬火实验表明，•OH是诱导OTC光降解的主要活性物质。随着纳米气泡技术的发展，有望实现完全无化学品的绿色技术。这项研究提供了一种新颖的纳米气泡/ AOPs技术，该技术将更高效，更环保，并将在废水处理和饮用水净化中得到广泛应用。