ERASE-PFAS: Collaborative Research: Development of Quantitative Tools to Assess the Mechanisms and Full Poten-tial of UV-ARPs for the Treatment of PFASs in Water

PFAS（全氟和多氟烷基物质）是一组已被广泛使用了几十年的人造化学品。PFAS含有大量的碳氟键，这使得它们非常稳定。这种稳定性使它们被称为“永远的化学物质”。PFAS的广泛使用造成了广泛的土壤和水体污染。这一发现非常令人担忧，因为PFAS暴露与严重的健康影响有关，如癌症和出生缺陷。由于PFAS对大多数传统的化学和生物水处理工艺具有抗性，因此这一问题变得更加紧迫。一项对水中PFAS的破坏显示出希望的新技术是高级还原工艺（ARPs）。ARPs在水中产生电子，电子可以与PFAS反应，降解PFAS等卤化化合物。该项目的目的是确定ARPs修复PFAS污染水的潜力。这一目标将通过以下研究来实现：i)确定在基于电子的PFAS破坏过程中发生的重要反应，ii)开发用于预测ARP系统中PFAS降解的定量工具。本研究的成功完成为开发有效处理PFAS污染水的新技术提供了希望。通过研究生和本科生在研究中的参与和培训，以及在暑期培训项目中对高中STEM教师的培训，增加国家的STEM劳动力，对社会产生了额外的好处。水合电子是已知最强的还原剂之一。最近的研究表明，水合电子能够将全氟磺酸（包括全氟辛酸和全氟辛烷磺酸）中的氟原子还原为无毒氟化物。然而，阻碍水合电子用于PFAS破坏的一个重要障碍是缺乏对现实水中水合电子基过程的定量了解。该项目的目标是通过解决水合电子基PFAS降解的潜在机制限制，开发定量数据和工具，以评估基于紫外线的高级还原过程（UV-ARP）的全部潜力。这一总体目标将通过关注三个互补的目标来实现：1)表征亲本PFAS的水化电子破坏效率和绝对氟化物产量；2)开发预测真实水域中UV-ARPs对PFAS降解率所需的定量方法；3)使用这些定量工具开发“最佳案例”UV-ARP处理，并将此优化系统与其他PFAS降解技术进行比较。这些目标将通过最先进的时间分辨和稳态辐射分解技术，结合实验规模的UV-ARP实验和动力学建模来实现。该研究将通过高中STEM教师培训计划和本科研究人员在主要本科机构的参与，与教育和推广相结合。通过与橙县水区（全国最大的全面先进的水处理设施之一）合作，分享研究成果和水处理从业者的建议，为社会带来了额外的好处。这项研究的成功完成将提高ARPs在实际水域中处理PFAS的基础科学和工程潜力。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。

PFAS (per- and polyfluoroalkyl substances) are a group of man-made chemicals that have been widely used for many decades. PFAS contain numerous carbon-fluorine bonds that makes them extremely stable. This stability has led to them being called “forever chemicals.” The broad use of PFAS has resulted in widespread contamination of soil and water. This finding is of great concern, as PFAS exposure have been linked to serious health effects, such as cancer and birth defects. The urgency of this problem is made greater because PFAS are resistant to most conventional chemical and biological water treatment processes. One new technology that has shown promise for PFAS destruction in water is Advanced Reduction Processes (ARPs). ARPs produce electrons in water, which can react with PFAS to degrade halogenated compounds like PFAS. The goal of this project is to determine the potential of ARPs for remediating PFAS contaminated water. This goal will be achieved through research to: i) identify the important reactions occurring in the electron-based PFAS destruction process, and ii) develop quantitative tools for predicting PFAS degradation in ARP systems. Successful completion of this research holds promise to develop new technology to effectively treat PFAS contaminated water. Additional benefits to society result from increasing the Nation’s STEM workforce through the engagement and training of graduate and undergraduate students in research, as well as training of high school STEM teachers during summer training programs.Hydrated electrons are one of the strongest known reductants. Recent studies show that the hydrated electron is capable of reducing fluorine atoms in PFAS, including PFOA and PFOS, to non-toxic fluoride. However, a significant barrier preventing application of hydrated electrons for PFAS destruction is the lack of quantitative knowledge of hydrated electron-based processes in real-world waters. The goal of this project is to develop the quantitative data and tools necessary to assess the full potential of Ultraviolet-based Advanced Reduction Processes (UV-ARP) by addressing the underlying mechanistic limitations of hydrated electron-based PFAS degradation. This overall goal will be realized by focusing on three complementary objectives to: i) characterize the hydrated electron-based destruction efficiencies of parent PFAS and absolute fluoride yields, ii) develop the quantitative methods needed to predict PFAS degradation rates by UV-ARPs in real-world waters, and iii) use these quantitative tools to develop a “best case” UV-ARP treatment and compare this optimized system to other PFAS degradation technologies. These objectives will be accomplished using state-of-the-science time-resolved and steady-state radiolysis, combined with bench-scale UV-ARP experiments and kinetic modeling. The research will be integrated with education and outreach through high school STEM teacher training programs and engagement of undergraduate researchers at a primarily undergraduate institution. Additional benefits to society result from the sharing of research findings and recommendations for water treatment practitioners through partnership with the Orange County Water District, one of the largest full-scale advanced water treatment facilities in the Nation. Successful completion of this research will advance the fundamental science and engineering potential of ARPs for PFAS treatment in real-world waters.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.