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

全氟和多氟烷基物质对土壤和水的污染是一个全国性的问题。某些PFAS化学物质已在超过95%的美国人口的血液中检测到。土壤在很大程度上影响了地下水和农作物的质量，而这些是人类接触这些化学品的潜在途径。处理PFAS污染的挑战来自其化学结构，导致对环境中生物降解的强烈抵抗力。然而，热过程，如森林火灾是已知的诱导PFAS化学物质在土壤中的物理和化学变化。这个CAREER项目的目标是了解PFAS化学品在热处理过程中在土壤中的稳定性和分解。更深入地了解这些过程是必要的热技术的发展，以清理PFAS污染的土壤，保护人类和生态健康。这项研究的成功完成将使科学家能够准确地预测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学的实践实验来加强学习，也给社会带来了额外的好处。通过外联、会议介绍和期刊出版物向公众、补救专业人员和其他利益攸关方传播结果将产生更多的好处。本项目由CBET环境工程项目和EPSCoR项目共同资助，旨在阐明热处理过程中PFAS在土壤中的转化机制。PFAS在高温下的反应途径将通过逐步实验评估各种PFAS类在不同的气相在各种土壤和参考土壤成分的热处理。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;评估热处理作为PFAS污染土壤的潜在修复方法的关键信息。这项研究的一个新的方面产生于使用一种创新的识别方法的基础上连续交错扫描在低和高碰撞能量的飞行时间质谱。这项研究的成功完成将产生关键的洞察到各类PFAS的热稳定性，增强对森林火灾期间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归宿和迁移模型中的一个隐含假设。该项目的教育目标是通过本科生参与精心设计的项目来促进对STEM的理解。学生将运用课堂上学到的知识来解决有趣和相关的现实问题。国家STEM劳动力的多样性将通过代表性不足的群体参与研究来扩大。该项目由CBET的环境工程项目和刺激竞争研究的既定项目（EPSCoR）共同资助。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 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.