Department of Civil, Environmental, and Construction Engineering, Texas Tech University, Box 41023, Lubbock, Texas 79409, United States.
Engineering and Management, Clarkson University, Potsdam, New York 13699, United States.
Environ Sci Technol. 2021 Jul 20;55(14):9805-9816. doi: 10.1021/acs.est.0c08069. Epub 2021 Jul 6.
Varying transport potential of cationic, zwitterionic, and anionic per- and polyfluoroalkyl substances (PFASs) may pose challenges for remediation of aqueous film forming foam (AFFF) impacted sites, particularly during groundwater extraction. Slow desorption of stronger sorbing, zwitterionic, and cationic PFASs may cause extended remediation times and rebound in aqueous PFAS concentrations. Persulfate oxidation has the potential to convert a complex mixture of PFASs into a simpler and more recoverable mixture of perfluoroalkyl acids (PFAAs). AFFF-impacted soils were treated with heat-activated persulfate in batch reactors and subjected to 7-day leaching experiments. Soil and water were analyzed using a combination of targeted and high resolution liquid chromatography mass spectrometry techniques as well as the total oxidizable precursors assay. Following oxidation, total PFAS composition showed the expected shift to a higher fraction of PFAAs, and this led to higher total PFAS leaching in pretreated reactors (108-110%) vs control reactors (62-90%). In both pretreated and control soils, precursors that remained following leaching experiments were 61-100% cationic and zwitterionic. Results suggest that persulfate pretreatment of soils has promise as an enhanced recovery technique for remediation of total PFASs in impacted soils. They also demonstrate that PFAS distribution may have been altered at sites where in situ chemical oxidation was applied to treat co-occurring contaminants of concern.
阳离子型、两性离子型和阴离子型全氟和多氟烷基物质 (PFASs) 的不同传输潜力可能给受水性成膜泡沫 (AFFF) 影响的场地的修复带来挑战，尤其是在地下水抽取期间。强吸附的两性离子型和阳离子型 PFASs 的缓慢解吸可能会导致更长的修复时间和水中 PFAS 浓度的反弹。过硫酸盐氧化有可能将 PFASs 的复杂混合物转化为更简单、更易回收的全氟烷基酸 (PFAAs) 混合物。用过硫酸盐在批量反应器中处理受 AFFF 影响的土壤，并进行为期 7 天的浸出实验。使用靶向和高分辨率液相色谱质谱技术以及总可氧化前体测定法对土壤和水进行分析。氧化后，总 PFAS 组成显示出预期的向更高比例 PFAAs 的转变，这导致预处理反应器中的总 PFAS 浸出率更高（108-110%）与对照反应器（62-90%）相比。在预处理和对照土壤中，浸出实验后残留的前体均为 61-100%的阳离子型和两性离子型。结果表明，过硫酸盐预处理土壤作为一种增强的回收技术，有望用于修复受影响土壤中的全氟烷基物质。它们还表明，在原位化学氧化用于处理同时存在的关注污染物的地点，PFAS 的分布可能已经发生了变化。
