聚合,而不是化: perfluorooctanoic 酸, perfluorobutanesulfonic 酸和 perfluorooctanesulfonate 在水溶液中的行为
Tess N Sobolewski1, J Luke Findlay1, Jackilyn E Hemphill1
1Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States.
Langmuir : the ACS journal of surfaces and colloids
|November 14, 2024
概括
这项研究表明,常见的PFAS化学物质如PFOA,PFBS和PFOS在溶液中形成聚合物,而不是菌. 它们的行为依赖于pH值,影响表面活动和聚合物形成.
科学领域:
- 环境化学环境化学
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
背景情况:
- 和多基基物质 (PFAS) 是广泛使用的合成化学品,具有多种工业应用.
- 了解PFAS的溶液行为是非常重要的,因为它们的环境持久性和潜在的健康影响.
- 之前的研究报告了PFAS的不同临界菌度 (CMC),导致对其聚合行为的理解存在差异.
研究的目的:
- 为了研究 perfluorooctanoic 酸 (PFOA), perfluorobutanesulfonic 酸 (PFBS) 和 perfluorooctanesulfonate (PFOS) 的表面和散装溶液的行为.
- 为了确定这些PFAS在不同的pH条件下在水溶液中形成或聚合物.
- 为了协调关于PFAS CMC和聚合的相互矛盾的文献数据.
主要方法:
- 测量表面张力以评估表面活动.
- 导电性实验探测散装溶液的特性,并检测微粒形成.
- 动态光散射 (DLS) 用于描述粒子大小和聚合.
- 电子显微镜 (Cryo-EM) 用于可视化溶液结构.
主要成果:
- PFAS表面活性对溶液pH高度敏感,在酸性条件下观察到PFOA的表面pH值较低.
- 导电性和表面张力数据表明,PFOS在pH值8.0下1mM以下的微粒形成开始,低于此前报告的水平.
- DLS 和 Cryo-EM 揭示了不同的聚合物 (50-150 nm) 而不是微粒的形成,其大小取决于度和温度.
结论:
- 这三种经过研究的EPA监管的PFAS表面活性剂在水溶液中形成聚合物,而不是小粒.
- 溶液的pH显著影响PFAS聚合行为和表面活动.
- 这些发现提供了这些PFAS聚合形成的第一个证据,并有助于解释报告的CMC的变化.
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