School of Environment, State Key Joint Laboratory of Environmental Simulation and Pollution Control (SKLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control, Tsinghua University, Beijing, 100084, China.
School of Environment, State Key Joint Laboratory of Environmental Simulation and Pollution Control (SKLESPC), Beijing Key Laboratory for Emerging Organic Contaminants Control, Tsinghua University, Beijing, 100084, China; School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
Chemosphere. 2021 Jun;273:128435. doi: 10.1016/j.chemosphere.2020.128435. Epub 2020 Oct 13.
Antibiotics are widespread in the environment with notable ecological risk, for which efficient and green removal technologies are demanded. As a kind of g-CN-based material with remarkable photocatalytic property, OCN is an oxygen- and nitrogen-linked carbon nitride organic polymer which can be synthesized through a single-step thermal polymerization method. In this study, OCN was applied for the visible-light-driven photocatalytic degradation of a typical fluoroquinolone (FQ) antibiotics enrofloxacin (ENR). The photocatalysis process achieved over 97% ENR removal within 60 min with 0.4 mg/L OCN and 4 mg/L ENR at pH 8.2. The photocatalytic mechanism of OCN at different pH was studied for the first time. It was shown that O, O and h made contributions at neutral or basic pH and O contributes the most (57.6% at pH 8.2), while ⋅OH played a role only under acidic condition with a contribution rate of 23.8% at pH 3.2. The cleavage of the piperazine ring and the quinolone ring were two main degradation pathways. The common water constituents humic acid and NO showed a dual effect, but HCO and Cl inhibited the degradation. The effect of different water matrices was tested under natural sunlight and it was only a tiny disturbance to the degradation rates. The biotoxicity test conducted using Vibrio fischeri indicated that the toxicity of degradation products became negligible after 3 h. This study demonstrated that OCN is a promising candidate for the advanced treatment and in-situ remediation.
抗生素在环境中广泛存在，具有显著的生态风险，因此需要高效、绿色的去除技术。OCN 是一种基于 g-CN 的材料，具有显著的光催化性能，是一种氧氮连接的碳氮有机聚合物，可通过一步热聚合方法合成。本研究将 OCN 应用于典型氟喹诺酮（FQ）抗生素恩诺沙星（ENR）的可见光驱动光催化降解。在 pH 值为 8.2 时，光催化过程在 60 分钟内实现了超过 97%的 ENR 去除，OCN 用量为 0.4mg/L，ENR 用量为 4mg/L。首次研究了 OCN 在不同 pH 值下的光催化机制。结果表明，O、O 和 h 在中性或碱性 pH 值下都有贡献，而 O 的贡献最大（在 pH 值为 8.2 时为 57.6%），而 ⋅OH 仅在酸性条件下起作用，在 pH 值为 3.2 时的贡献率为 23.8%。哌嗪环和喹诺酮环的断裂是两种主要的降解途径。常见的水成分腐殖酸和 NO 表现出双重作用，但 HCO 和 Cl 抑制了降解。在自然阳光下测试了不同水基质的影响，对降解速率只有微小的干扰。使用发光菌进行的生物毒性测试表明，降解产物的毒性在 3 小时后变得可以忽略不计。本研究表明，OCN 是一种很有前途的高级处理和原位修复候选物。
