Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA.
Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA.
J Hazard Mater. 2023 Oct 5;459:132039. doi: 10.1016/j.jhazmat.2023.132039. Epub 2023 Jul 12.
Acidimicrobium sp. Strain A6 (A6) can degrade perfluoroalkyl acids (PFAAs) by oxidizing NH while reducing Fe(Ⅲ). However, supplying and distributing Fe(III) phases in sediments is challenging since surface charges of Fe(III)-phases are typically positive while those of sediments are negative. Therefore, ferrihydrite particles were coated with polyacrylic acid (PAA) with four different molecular weights, resulting in a negative zeta potential on their surface. Zeta potential was determined as a function of pH and PAA loading, with the lowest value observed when the PAA/ferrihydrite ratio was > 1/5 (w/w) at a pH of 5.5. Several 50-day incubations with an A6-enrichment culture were conducted to determine the effect of PAA-coated ferrihydrite as the electron acceptor of A6 on the Feammox activity and PFOA degradation. NH oxidation, PFOA degradation, production of shorter-chain PFAS, and F were observed in all PAA-coated samples. The 6 K and 450 K treatments exhibited significant reductions in PFOA concentration and substantial F production compared to incubations with bare ferrihydrite. Electrochemical impedance spectroscopy showed lowered charge transfer resistance in the presence of PAA-coated ferrihydrite, indicating that PAAs facilitated electron transfer to ferrihydrite. This study highlights the potential of PAA-coated ferrihydrite in accelerating PFAS defluorination, providing novel insights for A6-based bioremediation strategies.
嗜酸微生物菌株 A6（A6）可以通过氧化 NH 同时还原 Fe(Ⅲ)来降解全氟烷基酸（PFAAs）。然而，在沉积物中供应和分布 Fe(Ⅲ)相具有挑战性，因为 Fe(Ⅲ)相的表面电荷通常为正，而沉积物的表面电荷为负。因此，用四种不同分子量的聚丙烯酸（PAA）对水铁矿颗粒进行了包覆，使其表面带负电荷。通过测定 pH 值和 PAA 负载量之间的关系来确定 ζ 电位，当 PAA/水铁矿的比例（w/w）在 pH 值为 5.5 时大于 1/5 时，观察到 ζ 电位最低。进行了多次为期 50 天的 A6 富集培养实验，以确定作为 A6 电子受体的 PAA 包覆水铁矿对 Feammox 活性和 PFOA 降解的影响。在所有 PAA 包覆的样品中均观察到 NH 氧化、PFOA 降解、较短链 PFAS 和 F 的生成。与 bare ferrihydrite 相比，6K 和 450K 处理显著降低了 PFOA 浓度并产生了大量的 F。电化学阻抗谱表明，在 PAA 包覆水铁矿存在的情况下，电荷转移电阻降低，表明 PAAs 促进了电子向水铁矿的转移。本研究强调了 PAA 包覆水铁矿在加速 PFAS 脱氟方面的潜力，为基于 A6 的生物修复策略提供了新的见解。
