Effective stabilization of per- and polyfluoroalkyl substances (PFAS) precursors in wastewater treatment sludge by surfactant-modified clay
Effective stabilization of per- and polyfluoroalkyl substances (PFAS) precursors in wastewater treatment sludge by surfactant-modified clay
复制标题
表面活性剂改性粘土有效稳定废水处理污泥中的全氟烷基物质和多氟烷基物质 (PFAS) 前体
DOI：
10.1016/j.chemosphere.2023.140081
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发表时间：
2023
期刊：
影响因子：
8.8
通讯作者：
Liang, Yanna
中科院分区：
文献类型：
--
作者：
Jiang, Tao;Pervez, Md. Nahid;Quianes, Monica M.;Zhang, Weilan;Naddeo, Vincenzo;Liang, Yanna
在农业用地中使用含有全氟烷基物质和多氟烷基物质（PFAS）的生物固体或处理过的污水污泥以及在垃圾填埋场中处置污泥对人类和环境构成了很高的风险。尽管 PFAS 前体尚未受到监管，但它们向高度监管的全氟烷基酸 (PFAA) 的潜在转变可能使它们能够作为长期来源，并使 PFAA 的修复成为一项持续的任务。因此，处理污水污泥中的前体比处理或去除 PFAA 更重要，当然也同样重要。在本研究中，与未改性粘土和粉状活性炭 (PAC) 相比，评估了绿色表面活性剂改性粘土吸附剂稳定污泥中两种代表性 PFAA 前体的功效，例如 N-乙基全氟辛烷磺酰胺乙酸 (N-EtFOSAA) 和 6:2 氟调聚物磺酸 (6:2 FTSA)。结果表明，N-EtFOSAA 和 6:2 FTSA 由于疏水性和官能团等物理化学性质不同，在无吸附剂的污泥中表现出不同的吸附行为。在三种吸附剂中，在实验结束时（47 天），与未进行改性的对照相比，改性粘土将 N-EtFOSAA 和 6:2 FTSA 的水浸出率分别降低了 91.5% 和 95.4%。在同一时间内，PAC 使 N-EtFOSAA 和 6:2 FTSA 的水浸出率分别降低了 60.6% 和 37.3%。同时，未改性的粘土表现出较差的稳定效果，甚至促进了前体的浸出。这些发现表明，改性粘土具有稳定前体的潜力，而在稳定过程中应避免使用带负电荷和/或亲水性吸附剂，例如未改性粘土。这些结果可以为开发有效的改良剂以稳定污泥或生物固体中的 PFAS 提供有价值的信息。未来的研究应该使用废水处理设施中的实际污泥来评估稳定方法的长期效果。
The application of biosolids or treated sewage sludge containing per- and polyfluoroalkyl substances (PFAS) in agricultural lands and the disposal of sludge in landfills pose high risks to humans and the environment. Although PFAS precursors have not been regulated yet, their potential transformation to highly regulated perfluoroalkyl acids (PFAAs) may enable them to serve as a long-term source and make remediation of PFAAs a continuing task. Therefore, treating precursors in sewage sludge is even more, certainly not less, critical than treating or removing PFAAs. In this study, a green surfactant-modified clay sorbent was evaluated for its efficacy in stabilizing two representative PFAA precursors in sludge, e.g., N-ethyl perfluorooctane sulfonamido acetic acid (N-EtFOSAA) and 6:2 fluorotelomer sulfonic acid (6:2 FTSA), in comparison with unmodified clay and powdered activated carbon (PAC). Results showed N-EtFOSAA and 6:2 FTSA exhibited distinct adsorption behaviors in the sludge without sorbents due to their different physicochemical properties, such as hydrophobicity and functional groups. Among the three sorbents, the modified clay reduced the water leachability of N-EtFOSAA and 6:2 FTSA by 91.5% and 95.4%, respectively, compared to controls without amendments at the end of the experiment (47 days). Within the same duration, PAC decreased the water leachability of N-EtFOSAA and 6:2 FTSA by 60.6% and 37.3%, respectively. At the same time, the unmodified clay demonstrated a poor stabilization effect and even promoted the leaching of precursors. These findings suggested that the modified clay had the potential for stabilization of precursors, while negatively charged and/or hydrophilic sorbents, such as the unmodified clay, should be avoided in the stabilization process. These results could provide valuable information for developing effective amendments for stabilizing PFAS in sludge or biosolids. Future research should evaluate the long-term effect of the stabilization approach using actual sludge from wastewater treatment facilities.