Enhancing transport and delivery of ferrihydrite nanoparticles via polymer encapsulation in PFAS-contaminated sediments to simulate PFAS defluorination by Acidimicrobium sp. Strain A6

项目摘要/摘要 全氟烷基和多氟烷基物质(PFAS)广泛存在于环境中，具有高度的稳定性。他们 存在于许多消费产品中，已合成了4000多种不同的全氟辛烷磺酸。其中 最常见和最令人担忧的是全氟辛酸(PFOA)和全氟 辛烷磺酸盐 (全氟辛烷磺酸)，美国环保局报告称，这些化合物可导致生殖和发育 实验动物的缺陷、肝和肾损害以及免疫学影响，它们可能 在动物实验中引起肿瘤。由于C-F键很强，没有脱氟作用和矿化作用 到目前为止，除了最近由Pfas进行的脱氟外，已有全氟化合物 发现并分离到Feammox细菌Acidimicrobium sp.菌株A6(A6)。 A6氧化铵(NH4)同时还原铁(Fe(III))，在这个过程中它也可以 将电子转移到全氟化铝并使其脱氟。生物修复/生物刺激通常需要 通过提供适当的电子供体/受体来实现适当的生物地球化学条件， 氧化还原电位操作，如果所需的有机体不存在，则进行生物增强。A6是 在富含铁的酸性土壤中很常见，这表明生物刺激可能是一种合适的技术 在许多情况下，将这种微生物用于全氟辛烷磺酸的生物修复计划。在电子给体/受体下 在条件有限的情况下，向含水层供应NH4很容易，而在空间和空间上供应则是一项挑战 分布着固相Fe(III)，需要新的方法来增强Fe(III)相的传输。我们 假设聚合物包裹的纳米亚铁水合物可以通过多孔介质输送 刺激A6的活性及其对PFAS的脱氟作用。因此，本项目的目标包括：(1) 开发聚合物包裹的纳米铁水晶石颗粒，具有更好的传输性能 多孔性介质；(2)确定聚合物包裹的纳米铁水合物是可生物利用的，以及 (3)通过土柱试验确定如何提供 聚合物包裹的纳米铁氢化物增强A6的活性及其对PFAS的脱氟作用。 该项目的结果将导致设计和操作生物修复的第一个方法 计划对全氟辛烷磺酸进行除氟，这些全氟辛烷磺酸对健康的影响越来越大，而饮用水是 主要暴露在人类身上。这将通过技术和实验方法相结合来实现。 材料科学、微生物学和水文学/环境工程。该项目将提供 关于如何提供Fe(III)源的新知识，它也有其他修复应用，提供了 关于如何刺激A6用于全氟辛烷磺酸和其他污染物的生物修复的新见解，并展示了如何 将这些发现整合到一个有效的PFAS生物修复计划中，该计划能够为 延长时间，以达到预期的最终浓度/水质目标。

Project Summary/Abstract Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment and highly stable. They are present in many consumer products and over 4000 different PFAS have been synthesized. Among the most common and of most concern are perfluorooctanoic acid (PFOA) and perfluoro octane sulfonate (PFOS), for which the EPA reports that these compounds can cause reproductive and developmental defects, liver and kidney damage, and immunological effects in laboratory animals, and that they may cause tumors in animal studies. Due to the strong C-F bond, no defluorination followed by mineralization of perfluorinated compounds has been reported so far, except PFAS defluorination by the recently discovered and isolated Feammox bacterium Acidimicrobium sp. Strain A6 (A6). A6 oxidizes ammonium (NH4+) while reducing ferric iron (Fe(III)), and it can during this process also transfer electrons to PFAS and defluorinate them. Bioremediation/biostimulation usually requires achieving proper biogeochemical conditions via the supply of appropriate electron donors/acceptors, redox potential manipulation, and bioaugmentation if the required organism is not present. A6 is common in iron-rich acidic soils, indicating that biostimulation could be an appropriate technology in many cases to use this organism for PFAS bioremediation schemes. Under electron donor/acceptor limiting conditions, it is easy to supply NH4+ to an aquifer, while it is challenging to supply and spatially distribute solid-phase Fe(III), requiring novel methods to enhance the transport of Fe(III) phases. We hypothesize that polymer encapsulated nano-ferrihydrite can be delivered throughout a porous medium to stimulate the activity of A6 and its defluorination of PFAS. Hence, the Aims of this project include: (1) develop polymer-encapsulated nano-ferrihydrite particles that have increased transport properties in a porous medium; (2) ascertain that the polymer-encapsulated nano-ferrihydrite is bioavailable and enhances PFAS defluorination by A6; and (3) determine via soil column experiments how to supply the polymer-encapsulated nano-ferrihydrite to enhance the A6 activity and its defluorination of PFAS. The outcome of this project will result in the first approach to design and operate a bioremediation scheme to defluorinate PFAS, which are of increasing health concern and for which drinking water is the main exposure for humans. This will be achieved by combining techniques and experimental methods from material science, microbiology, and hydrology/environmental engineering. The project will provide new knowledge on how to supply a Fe(III) source, which also has other remediation applications, provide new insights on how to stimulate A6 for the bioremediation of PFAS and other pollutants, and show how to integrate these findings for an effective PFAS bioremediation scheme that is able to operate for extended time periods in order to achieve desired final concentration/water quality goals.