Remediation of PFAS-impacted soils using magnetic activated carbon (MAC) and hydrothermal alkaline treatment (HALT)
Remediation of PFAS-impacted soils using magnetic activated carbon (MAC) and hydrothermal alkaline treatment (HALT)
复制标题
使用磁性活性炭 (MAC) 和水热碱处理 (HALT) 修复受 PFAS 影响的土壤
DOI：
10.1016/j.scitotenv.2023.168931
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发表时间：
2024
影响因子：
9.8
通讯作者：
Chu, Kung-Hui
中科院分区：
文献类型：
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作者：
Shih, Chih-Hsuan;Kim, Jinha;Yang, Shih-Hung;Soker, Ori;Strathmann, Timothy J.;Chu, Kung-Hui
全氟烷基物质和多氟烷基物质 (PFAS) 是一组具有生物累积性、毒性和持久性的合成污染物。 PFAS 释放的长期来源之一是受 PFAS 污染的土壤。在土壤中添加活性炭 (AC) 已显示出固定 PFAS 并降低 PFAS 生物利用度的潜力，但残留在处理过的土壤中的负载 PFAS 的废活性炭可能会导致再活化。在这里，我们报告了一种应对这一挑战的新方法。通过应用磁性活性炭 (MAC) 修复受 PFAS 影响的土壤，可以从处理后的土壤中回收负载 PFAS 的 MAC，并可以使用水热碱处理 (HALT) 破坏废 MAC 中吸附的 PFAS。当水/土比 (w/w) <0.07 或 > 1 时，可观察到有效的 MAC 回收。土壤有机含量和 pH 值会影响添加到土壤中的 MAC 对 PFAS 的吸附。使用 MAC 孵育三个月后，在有机物含量较低的酸性环境沙土中观察到高 PFAS 去除率 [PFOS (87.6%)、PFOA (83.8%) 和 6:2 FTSA (81.5%)]。相比之下，对于有机质含量高的花园土壤，MAC 对 PFAS 的去除效果较差。 MAC 还用于修复受水成膜泡沫 (AFFF) 影响和 PFAS 污染的老化土壤，其 PFAS 去除性能各异。 HALT 技术能够破坏和脱氟吸附在废 MAC 上的 PFAS。此外，经 HALT 处理的 MAC 保留了其磁性和 PFOS 吸附能力，表明经 HALT 处理的 MAC 具有潜在的可重复使用性。与传统的 PFAS 热破坏技术相比，考虑到 HALT 的能量足迹较低，MAC 和 HALT 的组合可能是治疗 PFAS 污染土壤的一种有前途的处理方案。
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic pollutants that are bioaccumulative, toxic, and persistent. One long-term source for PFAS release is PFAS-contaminated soil. Addition of activated carbon (AC) to soil has shown the potential to immobilize PFAS and reduce PFAS bioavailability, but PFAS-loaded spent AC remaining in the treated soil could lead to remobilization. Here we report a novel approach to address this challenge. By applying magnetic activated carbon (MAC) to remediate PFAS-impacted soil, the PFAS-loaded MAC can be retrieved from the treated soil and sorbed PFAS in the spent MAC can be destroyed using hydrothermal alkaline treatment (HALT). Effective MAC recovery was observed when water/soil ratios (w/w) were either <0.07 or > 1. Soil organic content and pH affected PFAS adsorption by the MAC added to soil. After three months of incubation with MAC, high PFAS removals [PFOS (87.6 %), PFOA (83.8 %), and 6:2 FTSA (81.5 %)] were observed for acidic environmental sandy soils with low organic content. In contrast, PFAS removal by MAC was poor for garden soils with high organic matter content. MAC was also used to remediate aqueous film-forming foam (AFFF)-impacted and PFAS-contaminated aged soils with varying PFAS removal performance. HALT technology was able to destroy and defluorinate PFAS adsorbed to the spent MAC. Additionally, the HALT-treated MAC retained its magnetic properties and PFOS sorption capacity, suggesting the potential reusability of HALT-treated MAC. Considering the low energy footprint of HALT compared to conventional PFAS thermal destruction techniques, the combination of MAC and HALT could be a promising treatment train for PFAS-contaminated soils.