文献类型：期刊文献

英文题名：Elevated nitrate promoted photodegradation of PAHs in aqueous phase: Implications for the increased nutrient discharge

作者：Liu, Zijin[1];Sun, Xianbo[1];Fu, Jie[2];Liu, Wen[3];Cai, Zhengqing[1,4]

机构：[1]East China Univ Sci & Technol, Natl Engn Res Ctr Ind Wastewater Detoxicat & Resou, Shanghai 200237, Peoples R China;[2]Huazhong Univ Sci & Technol, Sch Environm Sci & Engn, Wuhan 430074, Peoples R China;[3]Peking Univ, Minist Educ Coll Environm Sci & Engn, Key Lab Water & Sediment Sci, Beijing 100871, Peoples R China;[4]Shanghai Inst Pollut Control & Ecol Secur, Shanghai 200092, Peoples R China

年份：2023

卷号：443

外文期刊名：JOURNAL OF HAZARDOUS MATERIALS

收录：;EI(收录号：20224212975274);WOS:【SCI-EXPANDED(收录号:WOS:000876392200004)】；

基金：This study was financially supported by the Natural Science Foun- dation of Shanghai [21ZR1415600] , the National Natural Science Foundation of China [41807340] , and National Key R & D Program of China (2019YFC0408200) .

语种：英文

外文关键词：PAHs; Photochemical degradation; Nutrient discharge; Seawater; Environmental risks

摘要：Polycyclic aromatic hydrocarbons (PAHs) are frequently released in aqueous phase by oil spill or from other sources, and photochemical oxidation is one of their major weathering processes. In this study, the photo-chemical behavior of phenanthrene (PHE, as a representative PAH) were studied and the effects of nitrogenous compounds were evaluated. The results showed that nitrate was an effective photosensitizer for improving the photodegradation of PHE, but the promoting effect was less effective in seawater due to the presence of halogen ions; the ammonia played a negligible role on PHE degradation. The photochemical ionization was a key process for PHE degradation, it can be retarded due to the quenching of triplet excited state by dissolved oxygen, and the inhibition was most prominent in fresh water. The presence of nitrate increased the steady state concentration of center dot OH from 2.08 x 10-15 M to 1.04 x 10-14 M in fresh water, and from 1.5 x 10-16 M to 2.08 x 10-15 M in seawater. The secondary-order reaction rate constant between PHE and center dot OH (k center dot OH,PHE) was determined as 5.70 x 109 M-1 s-1. Similar trend was observed for 1O2. The contribution of center dot OH to PHE removal was more prominent in fresh water than in seawater due to the quenching effects of halogen, and the increasing of nitrate enlarged the contribution of center dot OH. Two possible PHE degradation pathways were proposed based on GC-MS analysis and DFT calculation. The Quantitative Structure-activity Relationship (QSAR) evaluation showed that some degradation intermediates were more toxic than PHE, but the total environmental risk was still diminished due to the low percentage of toxic intermediates. This study provided theoretical and experimental insights into the influence of nitrogenous compounds on the photodegradation of PHAs in water environment.