Indirect photodegradation of sulfadimidine and sulfapyridine: Influence of CDOM components and main seawater factors.
Indirect photodegradation of sulfadimidine and sulfapyridine: Influence of CDOM components and main seawater factors.
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DOI：
10.1016/j.chemosphere.2023.138821
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发表时间：
2023-05
期刊：
影响因子：
8.8
通讯作者：
Mingyan Xiao;Xinyu Tang;Xiaoyong Shi;Chuan-song Zhang
中科院分区：
文献类型：
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作者：
Mingyan Xiao;Xinyu Tang;Xiaoyong Shi;Chuan-song Zhang
研究了发色溶解性有机物（CDOM）存在下磺胺二甲嘧啶（SM 2）和磺胺吡啶（SP）的间接光降解，并研究了主要海洋因子（盐度、pH、NO3-和HCO 3-）的影响。反应中间体（RI）捕获实验表明，三重态CDOM（3CDOM*）对SM 2的光解贡献率为58%，对SP的光解贡献率分别为32%、34%和34%。在四种CDOMs中，JKHA的荧光效率最高，对SM 2和SP的光解速率最快。CDOM由一种本地腐殖质（C1）和两种外来腐殖质（C2和C3）组成。C3的荧光强度最强，其产生RI的能力最强，分别占SRHA、SRFA、SRNOM和JKHA总荧光强度的22%、11%、9%和38%，表明CDOM荧光组分在SM 2和SP的间接光降解中占优势。CDOM的光敏化作用是在其荧光强度降低后发生的，大量的RI（3CDOM*、HO·和1 O2等）在CDOM的光敏化过程中产生。通过能量转移和电子转移产生了2，3-三唑-2-酮，然后这些反应物与SM 2和SP反应，导致光解。随着盐度的增加，SM 2和SP的光解受到连续刺激。SM 2的光降解速率随pH值的增加先增大后减小，NO3-和HCO 3-对SM 2和SP的间接光降解影响不大。本研究有助于更好地了解SM 2和SP在海洋中的归宿，并为其他磺胺类药物的转化提供新的见解。海洋生态环境。
This study investigated the indirect photodegradation of sulfadimidine (SM2) and sulfapyridine (SP) in the presence of chromophoric dissolved organic matter (CDOM), and studied the influences of main marine factors (salinity, pH, NO3−and HCO3−). Reactive intermediate (RI) trapping experiments demonstrated that triplet CDOM (3CDOM*) played a major role in the photodegradation of SM2with a 58% photolysis contribution, and the contributions to the photolysis of SP were 32%, 34% and 34% for3CDOM*, hydroxyl radical (HO·) and singlet oxygen (1O2), respectively. Among the four CDOMs, JKHA, with the highest fluorescence efficiency, exhibited the fastest rate of SM2and SP photolysis. The CDOMs were composed of one autochthonous humus (C1) and two allochthonous humus (C2 and C3). C3, with the strongest fluorescence intensity, had the strongest capacity to generate RIs and accounted for approximately 22%, 11%, 9% and 38% of the total fluorescence intensity of SRHA, SRFA, SRNOM and JKHA, respectively, indicating the predominance of CDOM fluorescent components in the indirect photodegradation of SM2and SP. These results demonstrated the photolysis mechanism: The photosensitization of CDOM occurred after its fluorescence intensity decreased, and a large number of RIs (3CDOM*, HO· and1O2, etc.) were generated by energy and electron transfer, then these RIs reacted with SM2and SP to cause photolysis. The increase in salinity stimulated the photolysis of SM2and SP consecutively. The photodegradation rate of SM2first increased and then decreased with increasing pH, whereas the photolysis of SP was remarkably promoted by high pH but remained stable at low pH. NO3−and HCO3−had little effect on the indirect photodegradation of SM2and SP. This research may contribute to a better understanding of the fate of SM2and SP in the ocean and provide new insights into the transformation of other sulfonamides (SAs) in marine ecological environments.