State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, PR China.
Jiangsu Yangtze River Delta Environmental Science and Technology Research Institute Co., Ltd., Changzhou, Jiangsu 213100, PR China.
J Hazard Mater. 2023 Jun 15;452:131252. doi: 10.1016/j.jhazmat.2023.131252. Epub 2023 Mar 21.
To reveal the fate of anthracene (ANT) in soil, the photodegradation behavior of ANT was systematically studied using SiO to simulate a soil environment. Under xenon lamp irradiation, more than 90% of ANT loaded on SiO could be removed after 240 min. Moreover, the effects of water content, chloride ions (Cl) and humic acid (HA) were examined. It was found that the presence of water and HA can significantly inhibit the photolysis of ANT on SiO, while the addition of chloride alone has no obvious effect. However, when water is present, the inhibition effect of chloride became more obvious. According to radical quenching experiments and electron paramagnetic resonance (EPR) spectra, hydroxyl radicals (•OH) and chlorine radicals (Cl•) were formed in the system. Possible reaction pathways were speculated based on products identified by mass spectrometry. ANT was attacked by •OH to form hydroxylated products, which can be further hydroxylated and oxidized with the final formation of ring-opening products. ANT directly excited by light may also react with Cl• to produce chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs). Finally, the experimental results were verified on real soil. This study provides important information for understanding the photochemical transformation mechanism of ANT at the soil/air interface.
为了揭示蒽（ANT）在土壤中的命运，我们使用二氧化硅（SiO）来模拟土壤环境，系统地研究了 ANT 的光降解行为。在氙灯照射下，超过 90%负载在 SiO 上的 ANT 在 240 分钟后可以被完全去除。此外，还考察了水含量、氯离子（Cl）和腐殖酸（HA）的影响。结果发现，水和 HA 的存在可以显著抑制 ANT 在 SiO 上的光解，而单独添加氯离子则没有明显的影响。然而，当存在水时，氯离子的抑制作用变得更加明显。根据自由基猝灭实验和电子顺磁共振（EPR）谱，在该体系中形成了羟基自由基（•OH）和氯自由基（Cl•）。根据质谱鉴定的产物，推测了可能的反应途径。ANT 被•OH 攻击生成羟基化产物，这些产物可以进一步羟基化和氧化，最终形成开环产物。ANT 也可能直接被光激发与 Cl•反应，生成氯化多环芳烃（Cl-PAHs）。最后，在实际土壤上验证了实验结果。本研究为理解土壤/空气界面上 ANT 的光化学转化机制提供了重要信息。
