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Chen Z, Dong R, Wang X, Huang L, Qiu L, Zhang M, Mi N, Xu M, He H, Gu C. Efficient Decomposition of Perfluoroalkyl Substances by Low Concentration Indole: New Insights into the Molecular Mechanisms. Environ Sci Technol 2024. [PMID: 38329941 DOI: 10.1021/acs.est.3c08453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Perfluoroalkyl substances (PFAS) are a class of persistent organic pollutants known as "forever chemicals". Currently, the hydrated electron-based advanced reduction process (ARP) holds promise for the elimination of PFAS. However, the efficiency of ARP is often challenged by an oxygen-rich environment, resulting in the consumption of hydrated electron source materials in exchange for the high PFAS decomposition efficiency. Herein, we developed a ternary system constructed by indole and isopropyl alcohol (IPA), and the addition of IPA significantly enhanced the PFOA degradation and defluorination efficiency in the presence of low-concentration indole (<0.4 mM). Meanwhile, opposite results were obtained with a higher amount of indole (>0.4 mM). Further exploring the molecular mechanism of the reaction system, the addition of IPA played two roles. On one hand, IPA built an anaerobic reaction atmosphere and improved the yield and utilization efficiency of hydrated electrons with a low concentration of indole. On the other hand, IPA suppressed the attraction between indole and PFOA, thus reducing the hydrated electron transfer efficiency, especially with more indole. In general, the indole/PFAS/IPA system significantly improved the PFAS destruction efficiency with a small amount of hydrated electron donors, which provided new insights for development of simple and efficient techniques for the treatment of PFAS-contaminated wastewater.
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Affiliation(s)
- Zhanghao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Ruochen Dong
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Xinhao Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Liuqing Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Longlong Qiu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Ming Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
- Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, P. R. China
| | - Na Mi
- Ministry of Ecology and Environment, Nanjing Institute of Environmental Science, Nanjing 210042, P. R. China
| | - Min Xu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
| | - Huan He
- School of Environment, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Cheng Gu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China
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McTaggart M, Malardier-Jugroot C. The role of helicity in PFAS resistance to degradation: DFT simulation of electron capture and defluorination. Phys Chem Chem Phys 2024; 26:4692-4701. [PMID: 38251935 DOI: 10.1039/d3cp04973f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2024]
Abstract
Defluorination of perfluorinated alkyl substances (PFASs) via the direct capture of excess electrons poses a promising path to environmental decontamination. Herein we show that quantum-chemical model optimization methods can be adapted to simulate the changes to molecular geometry that result from electron capture. These reaction pathways demonstrate that the introduction of an additional electron causes a loss of the helical arrangement along linear carbon tail chains. Regaining helicity is sufficiently favourable to enable fluoride release in C7-C10 PFAS chains; shorter chains are enthalpically hindered from degradation while the additional charge is stabilized on longer chains by the greater entropy their flexibility permits. These results suggest that reductive PFAS treatment processes could be made more effective under high pressure or confined conditions.
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Affiliation(s)
- Matt McTaggart
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario, Canada.
| | - Cécile Malardier-Jugroot
- Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario, Canada.
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