Navarro Divina A, Kabiri Shervin, Ho Jonathan, Bowles Karl C, Davis Greg, McLaughlin Mike J, Kookana Rai S
CSIRO Environment, PMB 2, Glen Osmond, SA, 5064, Australia; School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, PMB1, Glen Osmond, South Australia, 5064, Australia.
School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, PMB1, Glen Osmond, South Australia, 5064, Australia.
Environ Pollut. 2023 Apr 15;323:121249. doi: 10.1016/j.envpol.2023.121249. Epub 2023 Feb 8.
Immobilisation/stabilisation is one of the most developed and studied approaches for treating soils contaminated with per- and poly-fluoroalkyl substances (PFAS). However, its application has been inhibited by insufficient understanding of the effectiveness of added soil sorbents over time. Herein, we present results on the effectiveness of select carbon-based sorbents, over 4 years (longevity) and multiple laboratory leaching conditions (durability). Standard batch leaching tests simulating aggressive, worst-case scenario conditions for leaching (i.e., shaking for 24-48 h at high liquid/solid ratios) were employed to test longevity and durability of stabilisation in clay-loam and sandy-loam soils historically contaminated with PFAS (2 and 14 mg/kg ∑ PFAS). The different sorbents, which were applied at 1-6% (w/w), reduced leaching of PFAS from the soils to varying degrees. Among the 5 sorbents tested, initial assessments completed 1 week after treatment revealed that 2 powdered activated carbon (PAC) sorbents and 1 biochar were able to reduce leaching of PFAS in the soil by at least 95%. Four years after treatment, the performance of the PAC sorbents did not significantly change, whilst colloidal AC improved and was able to reduce leaching of PFAS by at least 94%. The AC-treated soils also appeared to be durable and achieved at least 95% reduction in PFAS leaching under repetitive leaching events (5 times extraction) and with minimal effect of pH (pH 4-10.5). In contrast, the biochars were affected by aging and were at least 22% less effective in reducing PFAS leaching across a range of leaching conditions. Sorbent performance was generally consistent with the sorbent's physical and chemical characteristics. Overall, the AC sorbents used in this study appeared to be better than the biochars in stabilising PFAS in the long term.
固定化/稳定化是处理受全氟和多氟烷基物质（PFAS）污染土壤最成熟且研究最多的方法之一。然而，由于对添加的土壤吸附剂随时间的有效性了解不足，其应用受到了限制。在此，我们展示了选定的碳基吸附剂在4年（寿命）和多种实验室淋溶条件（耐久性）下的有效性结果。采用标准批量淋溶试验模拟侵蚀性、最坏情况的淋溶条件（即高液固比下振荡24 - 48小时），以测试在历史上受PFAS污染（2和14毫克/千克∑PFAS）的黏壤土和砂壤土中稳定化的寿命和耐久性。以1 - 6%（w/w）施用的不同吸附剂不同程度地减少了土壤中PFAS的淋溶。在测试的5种吸附剂中，处理后1周完成的初步评估显示，2种粉末活性炭（PAC）吸附剂和1种生物炭能够将土壤中PFAS的淋溶减少至少95%。处理4年后，PAC吸附剂的性能没有显著变化，而胶体AC有所改善，能够将PFAS的淋溶减少至少94%。经AC处理的土壤在重复淋溶事件（5次提取）下似乎也具有耐久性，PFAS淋溶减少至少95%，且pH（pH 4 - 10.5）影响最小。相比之下，生物炭受老化影响，在一系列淋溶条件下减少PFAS淋溶的效果至少低22%。吸附剂性能总体上与吸附剂的物理和化学特性一致。总体而言，本研究中使用的AC吸附剂在长期稳定PFAS方面似乎优于生物炭。
