Photobleaching-induced changes in the optical and photochemical properties of algal organic matter.
Photobleaching-induced changes in the optical and photochemical properties of algal organic matter.
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DOI：
10.1016/j.watres.2023.120395
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发表时间：
2023-07
期刊：
影响因子：
12.8
通讯作者：
Shengquan Kong;Xiaojing Liu;Hongyu Jiang;Wenjie Hong;Jibiao Zhang;Weihua Song;Shuwen Yan
中科院分区：
文献类型：
--
作者：
Shengquan Kong;Xiaojing Liu;Hongyu Jiang;Wenjie Hong;Jibiao Zhang;Weihua Song;Shuwen Yan
藻类有机物(AOM)是内源溶解有机物(DOM)的重要来源，在蓝藻水华期间，藻类有机物与氰化毒素一起被高浓度释放。AOM后续的光漂白是一个需要研究的重要现象。从中国太湖养殖的蓝藻中提取了胞内有机物和胞外有机物。将IOM和EOM光漂白不同阶段产生的活性中间体的形成与苏万尼河DOM(SRDOM，参考标准DOM)进行了比较。结果表明，IOM、EOM和SRDOM的色素组分差异显著。IOM中的颜料有助于形成能量转移较强但电子转移能力有限的三重态能级池。值得注意的是，IOM在可见光区表现出最高的三重态量子产额，这表明它在更深水层的污染物降解方面具有潜在的意义。对于EOM，其中一个池表现出光解性和显著的电子转移能力，表明它是一个高能三重态成分。此外，在提取的AOM中检测到三种氰基毒素(MC-LR、ACA和ATX-a)，并在AOM光漂白过程中监测了它们的光降解情况。这突出了AOM作为光敏剂在水体的自然自清洁机制中的潜在作用，促进了通过光化学反应降解有机污染物。这项研究的结果有助于理解AOM的动态性质及其在环境过程中的意义。
Algal organic matter (AOM), a significant source of endogenous dissolved organic matter (DOM) is released in high concentrations during cyanobacterial blooms, along with cyanotoxins. Subsequent photobleaching of AOM is an important phenomenon to investigate. In this study, intracellular organic matter (IOM) and extracellular organic matter (EOM) were extracted from cultured cyanobacteria taken from Taihu Lake in China. The formation of photochemically produced reactive intermediates in different stages of IOM and EOM photobleaching was compared to Suwannee River DOM (SRDOM, reference standard DOM). Results revealed notable differences influenced by the pigment component among IOM, EOM, and SRDOM. The pigment in IOM contributed to a triplet state pool with strong energy-transfer but limited electron-transfer capabilities. Notably, IOM exhibited the highest triplets state quantum yield value in the visible region, suggesting its potential significance in pollutant degradation in deeper water layers. For EOM, one of the pools exhibits photolability and remarkable electron-transfer capability, indicating it as a high-energy triplet state component. Moreover, three cyanotoxins (MC-LR, ACA, and ATX-a) were detected in the extracted AOM, and their photodegradation was monitored during the AOM photobleaching process. This highlights the potential role of AOM as a photosensitizer in the natural self-cleaning mechanisms of water bodies, facilitating the degradation of organic pollutants through photochemical reactions. The findings of this study contribute to understanding the dynamic nature of AOM and its implications in environmental processes.