Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC.
Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan, ROC.
Chemosphere. 2021 May;271:129507. doi: 10.1016/j.chemosphere.2020.129507. Epub 2021 Jan 2.
Algae is able to accelerate the photodegradation rate of contaminants under sunlight irradiation, and this process can be attributed to algal substances, namely, intracellular organic matter (IOM) and extracellular organic matter (EOM). This study aimed to investigate the efficiencies and mechanisms of the photodegradation of three pharmaceuticals - acetaminophen (ACE), codeine (COD) and cephradine (CFD) - in the presence of Chlorella vulgaris and its algal substances. The result shows that a much higher photodegradation rate of acetaminophen was obtained in the presence of IOM (k = 0.250 hr) than in the presence of EOM (k = 0.060 hr). The photodegradation mechanisms of acetaminophen were demonstrated and verified by scavenger experiments and probe tests. The major reactive species for acetaminophen photodegradation was triplet-state IOM (IOM∗), which contributed 93.52% of the photodegradation, while ⋅OH was the secondary contributor (5.60%), with O contributing the least (0.88%). Chlorella vulgaris also effectively enhanced the photodegradation of codeine and cephradine. However, the photodegradation behaviors of codeine and cephradine in the presence of algal substances were different from those of acetaminophen, indicating that the photodegradation mechanisms might depend on the type of compound. This study not only demonstrates the effectiveness of algal substances in the photodegradation of acetaminophen, codeine and cephradine under sunlight irradiation but also provides a comprehensive study on the photodegradation mechanisms of acetaminophen in the presence of algal substances.
藻类能够在阳光照射下加速污染物的光降解速率，这一过程可归因于藻类物质，即细胞内有机物（IOM）和细胞外有机物（EOM）。本研究旨在研究小球藻及其藻类物质存在下三种药物——对乙酰氨基酚（ACE）、可待因（COD）和头孢氨苄（CFD）的光降解效率和机制。结果表明，在 IOM 存在下（k=0.250 hr），对乙酰氨基酚的光降解率远高于 EOM 存在下（k=0.060 hr）。通过清除实验和探针测试验证了对乙酰氨基酚的光降解机制。对乙酰氨基酚光降解的主要活性物质是三重态 IOM（IOM∗），对光降解的贡献为 93.52%，而 ⋅OH 为次要贡献者（5.60%），O 贡献最小（0.88%）。小球藻还能有效增强可待因和头孢氨苄的光降解。然而，在藻类物质存在下，可待因和头孢氨苄的光降解行为与对乙酰氨基酚不同，表明光降解机制可能取决于化合物的类型。本研究不仅证明了藻类物质在阳光照射下对乙酰氨基酚、可待因和头孢氨苄光降解的有效性，还对藻类物质存在下对乙酰氨基酚的光降解机制进行了全面研究。
