CAREER: ERASE-PFAS: Mechanistic Investigation of Thermal Decomposition of Poly- and Perfluoroalkyl Substances in the Soil Environment

全氟烷基和多氟烷基物质对土壤和水的污染是一个国家关注的问题。在超过95%的美国人的血液中检测到某些PFAS化学物质。土壤在很大程度上影响着地下水和农作物的质量，这是人类接触这些化学物质的潜在途径。处理PFAS污染的挑战来自于它们的化学结构，这种结构对环境中的生物降解具有很强的抵抗力。然而，已知诸如森林火灾等热过程会引起土壤中PFAS化学物质的物理和化学变化。这个CAREER项目的目标是了解PFAS化学物质在土壤热处理过程中的稳定性和分解。为了保护人类和生态健康，有必要对这些过程进行更深入的了解，以开发热技术来清理受PFAS污染的土壤。这项研究的成功完成将使科学家能够准确预测PFAS在各种热过程中的分解产物。对工程本科生的培训以及通过参与土壤化学和物理的动手实验来加强学习，对社会产生了额外的好处。通过外联、会议演讲和期刊出版物，将结果传播给公众、补救专业人员和其他利益相关者，将产生进一步的效益。该项目由CBET环境工程项目和促进竞争研究的既定项目（EPSCoR）共同资助。本CAREER项目的目标是阐明PFAS在土壤热处理过程中的转化机制。通过逐步实验评估不同类型PFAS在不同气相下在不同土壤和参考土壤组分中的热处理，确定PFAS在高温下的反应途径。结果将用于确定土壤性质、PFAS分子结构和环境大气对降解途径的综合影响；这些信息对于评估热处理作为一种潜在的修复pfas污染土壤的方法至关重要。本研究的一个新颖方面来自于使用一种创新的识别方法，该方法基于飞行时间质谱的低碰撞能量和高碰撞能量的连续交错扫描。本研究的成功完成将有助于深入了解不同类型PFAS的热稳定性，加深对森林火灾中PFAS在土壤环境中的命运的理解，并阐明PFAS的热分解机制。这一知识具有潜在的变革性，因为PFAS的高热稳定性是当前环境命运和运输模型的隐含假设。该项目的教育目标是通过让本科生参与设计良好的项目来促进对STEM的理解。学生将运用在课堂上学到的知识来解决有趣和相关的现实问题。通过研究中代表性不足的群体的参与，美国STEM劳动力的多样性将得到扩大。本项目由中国工业大学环境工程专业和促进竞争研究的既定计划（EPSCoR）共同资助。该奖项反映了美国国家科学基金会的法定使命，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 contamination of soil and water by per- and polyfluoroalkyl substances (PFAS) is a national concern. Certain PFAS chemicals have been detected in the blood of more than 95% of the US population. Soil largely contributes to the quality of groundwater and crops, which are potential human exposure pathways for these chemicals. The challenge of dealing with PFAS contamination results from their chemical structure that leads to strong resistance to biological degradation in the environment. However, thermal processes such as forest fires are known to induce physical and chemical changes of PFAS chemicals in soil. The goal of this CAREER project is to understand the stability and decomposition of PFAS chemicals in soil during thermal treatment. A deeper understanding of these processes is necessary for the development of thermal technologies to clean up soils contaminated by PFAS for the protection of human and ecological health. Successful completion of this research will enable scientists to accurately predict decomposition products of PFAS in various thermal processes. Additional benefits to society result from the training of engineering undergraduates and enhanced learning through participation in hands-on experiments in soil chemistry and physics. Further benefits will accrue from the dissemination of results to the public, remediation professionals, and other stakeholders through outreach, conference presentations, and journal publications. This project is jointly funded by the CBET Environmental Engineering program and the Established Program to Stimulate Competitive Research (EPSCoR).The goal of this CAREER project is to elucidate transformation mechanisms of PFAS in soil during thermal treatment. PFAS reaction pathways at elevated temperatures will be identified through stepwise experiments assessing the thermal treatment of various PFAS classes under different gas phases in various soils and reference soil components. Results will be used to determine the combined effects of soil properties, PFAS molecular structure, and ambient atmosphere on degradation pathways; information critical to assessing thermal treatment as a potential remediation method for PFAS-contaminated soils. A novel aspect of this research arises from the use of an innovative identification approach based on continuously interleaving scans at low and high collision energies of time-of-flight mass spectrometry. Successful completion of this research will yield critical insight into the thermal stability of various classes of PFAS, enhanced understanding of the fate of PFAS in the soil environment during forest fires, and elucidation of mechanisms of thermal decomposition of PFAS. This knowledge is potentially transformative because the high thermal stability of PFAS is an implicit assumption in current environmental fate and transport models. The educational objectives of this project are focused on advancing STEM understanding through the involvement of undergraduate students in well-designed projects. Students will apply knowledge learned in class to address interesting and relevant real-world problems. The diversity of the Nation’s STEM workforce will be broadened through the participation of underrepresented groups in the research. This project is jointly funded by Environmental Engineering program of CBET and the Established Program to Stimulate Competitive Research (EPSCoR).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.