ERASE PFAS: Mechanistic Investigation of PFAS Degradation using Powder Activated Carbon and Persulfate at Ambient Temperature

在美国，全氟烷基物质（PFAS）的生产、利用和处置已造成广泛的环境污染。PFAS通常被称为“永久化学品”，因为它们具有持久性，稳定性和对自然环境降解过程的抗性。此外，PFAS倾向于在人体内生物累积，越来越多的证据表明，几种严重的健康后果与PFAS暴露有关，包括疫苗反应降低，胆固醇水平升高和妊娠并发症。在过去的二十年中，PFAS越来越多地在地下水含水层中被检测到，这些含水层是美国许多社区的饮用水来源。然而，由于去除和破坏PFAS所需的广泛的基础设施和能源，PFAS污染地下水的处理可能是昂贵的。该项目的总体目标是研究潜在的科学和工程，以推进一种有前途的低能耗和低温处理工艺的开发和部署，该工艺利用过硫酸盐（PS），然后用粉末活性炭（PAC）活化，以捕获和破坏污染地下水中的PFAS。该项目的成功完成将使社会受益，因为它将促进过硫酸盐和PAC的利用，作为一种具有成本效益的破坏技术，用于处理和修复PFAS污染的地下水。通过教育和培训活动，包括指导密歇根大学的一名研究生和一名本科生，将为社会带来更多的好处。PFAS在商业产品、制造业和消防反应中的广泛使用导致了美国各地土壤和地下水的污染。由于碳-氟键的高强度，大多数PFAS在环境介质中不会发生自然衰减反应，如生物降解、光氧化、光解和水解。因此，处理PFAS污染的含水层通常需要从地下抽取受污染的地下水，然后在地面上清除和处置，这需要大量的基础设施和/或大量的能源投入。很少有处理技术能有效地就地破坏PFAS，特别是在环境温度下。本项目的目标是设计、评估和优化一种低能耗、低温的过程，用于使用过硫酸盐（PS）和粉末活性炭（PAC）从受污染的地下水中原位捕获和破坏PFAS。本研究的具体目的是：（1）评价PS/PAC处理一系列具有不同官能团的PFAS污染物的反应动力学;（2）阐明PS/PAC处理过程中PFAS转化和破坏的反应机理和自由基物种的作用;和（3）使用流通柱研究评估PS/PAC处理对PFAS污染地下水的处理和修复效果。该项目的成功完成有可能通过产生基础知识产生变革性影响，这些知识将促进过硫酸盐和粉末活性炭的利用，作为一种有效和具有成本效益的销毁技术，用于现场处理受PFAS影响的地下水。为了实现本项目的教育和推广目标，主要研究者（PI）计划招募和指导来自代表性不足背景的学生进行拟议的研究。此外，PI将开发一个互动教学模块，“了解PFAS和暴露预防”，为K-12学生在饮用水中检测到PFAS的社区展示。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The manufacturing, utilization, and disposal of perfluoroalkyl substances (PFAS) has caused widespread environmental contamination in the United States. PFAS are commonly referred to as “forever chemicals” due to their persistence, stability, and resistance to natural environmental degradation processes. In addition, PFAS tend to bioaccumulate in the human body, and mounting evidence suggests that several serious health outcomes are associated with PFAS exposure, including reduced vaccine response, increased cholesterol levels, and pregnancy complications. During the last two decades, PFAS have been increasingly detected in groundwater aquifers which serve as sources of drinking water for many communities throughout the United States. However, the treatment of PFAS contaminated groundwater can be expensive due to the extensive infrastructure and energy required to remove and destroy PFAS. The overarching goal of this project is to investigate the underlying science and engineering to advance the development and deployment of a promising low-energy and low-temperature treatment process that utilizes persulfate (PS), followed by activation with powdered activated carbon (PAC), to capture and destroy PFAS from contaminated groundwater. The successful completion of this project will benefit society through the generation of fundamental knowledge that will advance the utilization of persulfate and PAC as a cost-effective destruction technology for the treatment and remediation of PFAS contaminated groundwater. Additional benefits to society will be accomplished through education and training activities including the mentoring of one graduate student and one undergraduate student at the University of Michigan.Widespread use of PFAS in commercial products, manufacturing, and fire-fighting response has led to the contamination of soils and groundwater throughout the United States. Due to the high strength of the carbon-fluorine bond, most PFAS do not undergo natural attenuation reactions in environmental media such as biodegradation, photo-oxidation, photolysis, and hydrolysis. As a result, treatment of PFAS contaminated aquifers often requires pumping contaminated groundwater from the subsurface followed by above ground removal and disposal, which requires extensive infrastructure and/or substantial energy inputs. Few treatment technologies efficiently destroy PFAS in situ, especially at ambient temperatures. The goal of this project is to design, evaluate, and optimize a low energy and low temperature process for in situ PFAS capture and destruction from contaminated groundwater using persulfate (PS) and powdered activated carbon (PAC). The specific objectives of the research are to (1) evaluate the reaction kinetics for a homologous series of PFAS contaminants with a range of functional groups using the PS/PAC treatment process; (2) elucidate the underlying reaction mechanisms and the role of radical species in PFAS transformation and destruction during PS/PAC treatment; and (3) assess the effectiveness of the PS/PAC treatment to treat and remediate PFAS contaminated groundwater using flow-through column studies. The successful completion of this project has the potential for transformative impact through the generation of fundamental knowledge that will advance the utilization of persulfate and powdered activated carbon as an efficient and cost-effective destruction technology for in situ treatment of PFAS-impacted groundwater. To implement the educational and outreach goals of this project, the Principal Investigator (PI) plans to recruit and mentor students from underrepresented backgrounds to work on the proposed research. In addition, the PI will develop an interactive instructional module, “Understanding PFAS and Exposure Prevention,” for K-12 students to present in communities where PFAS has been detected in drinking water.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.