Betaine-based polyfluoroalkyl surfactants are major perfluoroalkyl and polyfluoroalkyl surfactants (PFASs) found in many aqueous film-forming foams (AFFF) contaminated sites, while the transport behavior (i.e., mobility and adsorption) of PFAS-based betaines in groundwater and natural geosorbents interfaces remains unclear. To fill the knowledge gap, partitioning between of 15 AFFF-relevant PFASs, including 3 fluorotelomer sulfonates (FTSAs) and 3 polyfluoroalkyl betaines, and a model soil organic matter (SOM) were systematically assessed using a modified column chromatography approach. Results show that the retention of FTSAs (perfluoroalkyl chain-length of 4, 6, and 8) to SOM are similar to that of corresponding legacy perfluoroalkyl sulfonic acids (PFSAs) with the same chain length; FTSAs also respond to changes in solution chemistry similarly as PFSAs. At a solution pH of 5.9, based on the equilibrium speciation of the betaine-PFASs together with the experimental observations, the predominance of the neutral species over zwitterion gives rise to the relatively higher retention of polyfluoroalkyl betaines than perfluoroalkyl carboxylic acids (PFCAs) of equivalent chain-length. Sorption edges (minimal and maximum logK_oc values over a defined pH range) determined for three polyfluoroalkyl betaines are: 1.90–3.81 for perfluorooctaneamide betaine (PFOAB), 2.03–2.65 for perfluoroctane sulfonamide betaine (PFOSB), and < 3.04 for 6:2 fluorotelomer sulfonamide betaine (6:2 FTAB). Moreover, the increase in pH reduces the sorption of all PFAS to SOM. Increasing calcium ion (concentration ranges from 0.5 to 50 mM) has enhanced the sorption of anionic PFASs to SOM but decreased the sorption of the polyfluoroalkyl betaines. These findings are expected to improve the ability to anticipate and predict the possible subsurface location (i.e., predominantly in groundwater or sorbed to soil) of both novel and legacy PFASs.

基于甜菜碱的多氟烷基表面活性剂是在许多水性成膜泡沫（AFFF）污染场所中发现的主要全氟烷基和多氟烷基表面活性剂（PFAS），而基于PFAS的甜菜碱在地下水和天然地质吸附剂界面中的运输行为（即迁移性和吸附性）还不清楚。为了填补知识空白，使用改良的柱色谱方法系统地评估了15种与AFFF相关的PFAS（包括3种氟调聚物磺酸盐（FTSA）和3种多氟烷基甜菜碱）与模型土壤有机物（SOM）之间的分配。结果表明，FTSA（全氟烷基链长为4、6和8）对SOM的保留与相应的具有相同链长的传统全氟烷基磺酸（PFSA）的保留相似。FTSA也类似于PFSA对溶液化学变化做出响应。根据甜菜碱-PFAS的平衡形态以及实验观察，在溶液的pH值为5.9时，中性物质占优势的两性离子比多氟烷基甜菜碱的全氟烷基甜菜碱的保留量要高得多。链长。吸附边缘（最小和最大对数）对于三个多氟烷基甜菜碱，在规定的pH范围内确定的K _oc值是：全氟辛烷甜菜碱（PFOAB）为1.90–3.81，全氟辛烷磺酰胺甜菜碱（PFOSB）为2.03–2.65，6：2氟调聚物磺酰胺甜菜碱的<3.04（6： 2 FTAB）。而且，pH的增加会降低所有PFAS对SOM的吸附。增加钙离子（浓度范围从0.5到50 mM）已增强了阴离子PFAS对SOM的吸附，但降低了多氟烷基甜菜碱的吸附。预期这些发现将提高预测和预测新型和传统PFAS可能的地下位置（即主要在地下水中或吸附到土壤中）的能力。