Henry’s Law Constants of 15 Per- and Polyfluoroalkyl Substances Determined by Static Headspace Analysis
Henry’s Law Constants of 15 Per- and Polyfluoroalkyl Substances Determined by Static Headspace Analysis
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DOI：
10.1016/j.hazl.2022.100070
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发表时间：
2022-10
影响因子：
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通讯作者：
Ibrahim Abusallout;Chase Holton;Junli Wang;D. Hanigan
中科院分区：
文献类型：
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作者：
Ibrahim Abusallout;Chase Holton;Junli Wang;D. Hanigan
虽然人们认为一些全氟烷基和多氟烷基物质（PFAS）可能会从水溶液中挥发，但实验测量的亨利定律常数（kH，与空气：水分配系数同义）很少。这导致对PFAS的分配缺乏了解，无法预测污染地下水以上的浓度（例如，蒸汽侵入）。我们通过顶空分析和气液比的控制测量了27 PFAS的kH。15个PFAS产生适合forkH测量的质谱信号。在25 ° C下，实验测量的无量纲kH为：对于四种氟调聚物醇（FTOH）为0.31 - 2.82，对于三种氟调聚物磺酸盐（FTS）为0.09 - 0.18，对于三种碘化PFAS为0.30 - 1.01，对于两种磺酰胺为0.43 - 0.92，对于6：2氟调聚物烯烃为3.86，对于8：2氟调聚物羧酸为0.69，并且对于8：2氟调聚物丙烯酸酯为0.32。较长的氟烷基链长导致FTOH和FTS的kH增加，这是唯一研究链长的两组。全氟磺酸盐和羧酸盐的挥发性通常不足以测量，即使在pH低至1时，尽管两个官能团的氟调聚物都具有可测量的挥发性。温度效应很好地描述了范特霍夫方程。KH是没有显着不同的各种环境相关的矩阵证明了广泛的适用性的常数。
While it is thought that some per- and polyfluoroalkyl substances (PFAS) may volatilize from aqueous solutions, experimentally measured Henry’s Law constants (kH, synonymous with air : water partition coefficient) are scarce. This leads to a lack of understanding of the partitioning of PFAS and an inability to predict concentrations above contaminated groundwater (e.g., vapor intrusion). We measuredkHfor 27 PFAS via headspace analysis and manipulations of the gas to liquid phase ratio. Fifteen PFAS produced mass spectrometry signals suitable forkHmeasurements. At 25 °C the experimentally measured dimensionlesskHwere: 0.31 – 2.82 for four fluorotelomer alcohols (FTOHs), 0.09 – 0.18 for three fluorotelomer sulfonates (FTSs), 0.30 – 1.01 for three iodinated PFAS, 0.43 – 0.92 for two sulfonamides, 3.86 for 6:2 fluorotelomer olefin, 0.69 for 8:2 fluorotelomer carboxylic acid, and 0.32 for 8:2 fluorotelomer acrylate. Longer fluoroalkyl chain length resulted in increasedkHfor FTOHs and FTSs, the only two groups in which chain length was studied. Perfluorinated sulfonates and carboxylates were generally not volatile enough to be measured, even at pH as low as 1, although fluorotelomers of both functional groups were measurably volatile. Temperature effects were well described by the van’t Hoff equation.kHwas not significantly different in various environmentally relevant matrices demonstrating the broad applicability of the produced constants.