来自PFAS前体的PFOA异构体的表征及其降低性脱化
Jun Sun1, Wanutcha Lorpaiboon1, Nicholas Fox2
1UNSW School of Chemistry, University of New South Wales (UNSW), Sydney, NSW 2052, Australia.
Water research
|November 7, 2024
概括
分支 perfluorooctanoic 酸 (PFOA) 可能比我们想象的更常见,由 PFAS 前体形成. 使用维生素B12和零价值降解的一些分支PFOA异构体,为持久有机污染物补救提供了洞察力.
科学领域:
- 环境化学环境化学
- 有机化学 有机化学
- 环境科学 环境科学
背景情况:
- perfluorooctanoic酸 (PFOA) 是一个持久性有机污染物根据斯德哥尔摩公约.
- 分支PFOA异构体的研究比线性异构体少,原因是分析上的挑战和假设的较低度.
- 了解PFOA异构体的形成和降解对于环境风险评估至关重要.
研究的目的:
- 调查从PFAS前体中分支PFOA形成的环境相关途径.
- 用维生素B12与零价值金属来评估线性和分支PFOA异构体的可降解性.
- 为了探索PFOA异构体的潜在脱路径.
主要方法:
- 使用TOP试验氧化AFFF样本以量化分支PFOA形成.
- 使用维生素B12 (VB12) 与零价值 (ZVZ) 或零价值铁 (ZVI) 的减少降解实验.
- 使用高分辨率质谱 (LC-Orbitrap) 和密度函数理论 (DFT) 计算进行分析.
主要成果:
- 水性薄膜形成泡 (AFFF) 样本显示,在TOP试验氧化后,分支PFOA度显著增加.
- 线性PFOA和特定的分支异构体 (3-甲基PFOA,5,5-二甲基PFOA) 抵抗了还原性脱.
- 大多数其他分支PFOA异构体在ZVZ-VB12系统中在10天内降解,降解速率与减少潜力相关.
结论:
- 分支PFOA异构体在环境中可能比以前估计的更为普遍.
- 该ZVZ-VB12系统显示了某些分支PFOA异构体的降解潜力.
- 对PFOA异构体特异性降解途径和环境行为的进一步研究是有必要的.
相关概念视频
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
5.8K
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
5.8K
Phase I Reactions: Reductive Reactions
180
Phase I biotransformation reductive reactions are chemical processes that modify drugs by introducing or revealing polar functional groups via reduction. Enzymes called reductases catalyze these reactions, playing a pivotal role in drug metabolism by transforming lipophilic drugs into more polar, water-soluble metabolites for easy excretion. An essential type of reductive reaction is the carbonyl group reduction, where aldehydes and ketones are reduced to alcohols. An example is the...
180
Radical Formation: Elimination
1.7K
Another method of radical formation is the elimination process. It is the opposite of the addition route and is driven by the instability of the radical. For example, as depicted in Figure 1, dibenzoyl peroxide yields a pair of unstable radicals upon homolysis. Given its instability, this radical spontaneously undergoes elimination via a C–C bond cleavage to form a relatively more stable phenyl radical. The mechanism involves cleavage of the bond between the α and β positions...
1.7K
Oxidation of Phenols to Quinones
2.9K
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox...
2.9K


