Citation: Hanchun Chen, Mingyi Liu, Haodong Ji. Principle of excited state defluorination for perfluorocarboxylic acids in photolysis reaction[J]. Chinese Chemical Letters, ;2026, 37(7): 112273. doi: 10.1016/j.cclet.2025.112273 shu

Principle of excited state defluorination for perfluorocarboxylic acids in photolysis reaction

Eco-environment and Resource Efficiency Research Laboratory, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China

jihaodong@pku.edu.cn

Received Date: 22 May 2025
Revised Date: 17 November 2025
Accepted Date: 11 December 2025
Available Online: 12 December 2025

Figures(3)

The degradation of perfluorocarboxylic acids (PFCAs), persistent organic pollutants, remains a significant environmental challenge. Photolysis represents a key pathway for their degradation, yet the molecular mechanisms driving defluorination and decarboxylation remain unclear. This study investigates the first step of direct PFCA photolysis by analyzing excitation properties using density functional theory (DFT), aiming to elucidate the relationship between electronic structure changes and degradation pathways. To better demonstrate and analyze the impact of internal factors on the first step of PFCAs photolysis, quantum chemical calculations were conducted to quantify and compare the molecule’s properties in the ground state and the excited state, aiming to explore the changes in the molecule’s behavior. Key parameters, including α C–F bond elongation (0.31%–1.62%), α C–C bond contraction (−6.23% to −9.10%), and excitation energy reduction (5.76–5.47 eV), revealed chain-length-dependent trends. The lower bond dissociation energy of α C–C (90–93 kcal/mol) compared to α C–F (116–124 kcal/mol) rationalized the dominance of decarboxylation over defluorination. Charge transfer spectroscopy further indicated localized n → π* excitation at carboxyl groups, promoting decarboxylation. A quantitative structure-activity relationship (QSAR) model linking hole-electron indices to degradation rates (R² = 0.91) was developed and validated via leave-one-out cross-validation (RMSE = 0.338). These findings not only advance the mechanistic understanding of PFCA photolysis but also provide a predictive tool for optimizing UV-based water treatment systems targeting persistent fluorinated pollutants.
- Perfluorocarboxylic acids,
- Excitation,
- DFT calculations,
- Photolysis,
- Persistent organic pollutants
1. [1]
  L. Ahrens, M. Bundschuh, Environ. Toxicol. Chem. 33 (2014) 1921–1929. doi: 10.1002/etc.2663
2. [2]
  Z. Wang, I.T. Cousins, M. Scheringer, K. Hungerbühler, Environ. Int. 60 (2013) 242–248. doi: 10.1016/j.envint.2013.08.021
3. [3]
  X. Dauchy, V. Boiteux, A. Colin, et al., Chemosphere 214 (2019) 729–737. doi: 10.1016/j.chemosphere.2018.10.003
4. [4]
  J.C. D’eon, S.A. Mabury, Environ. Health Perspect. 119 (2011) 344–350. doi: 10.1289/ehp.1002409
5. [5]
  K.A. Barzen-Hanson, S.E. Davis, M. Kleber, J.A. Field, Environ. Sci. Technol. 51 (2017) 12394–12404. doi: 10.1021/acs.est.7b03452
6. [6]
  J.P. Benskin, B. Li, M.G. Ikonomou, J.R. Grace, L.Y. Li, Environ. Sci. Technol. 46 (2012) 11532–11540. doi: 10.1021/es302471n
7. [7]
  N. Yamashita, K. Kannan, S. Taniyasu, et al., Mar. Pollut. Bull. 51 (2005) 658–668. doi: 10.1016/j.marpolbul.2005.04.026
8. [8]
  Z. Wang, I.T. Cousins, M. Scheringer, R.C. Buck, K. Hungerbühler, Environ. Int. 70 (2014) 62–75. doi: 10.1016/j.envint.2014.04.013
9. [9]
  Y. Liu, Y. Zhang, J. Li, et al., China Environ. Pollut. 246 (2019) 34–44. doi: 10.1016/j.envpol.2018.11.113
10. [10]
  A.A. Rand, S.A. Mabury, Toxicology 375 (2017) 28–36.
11. [11]
  J.P. Giesy, J.E. Naile, J.S. Khim, P.D. Jones, J.L. Newsted, Aquatic toxicology of perfluorinated chemicals, in: D.M. Whitacre (Ed.), Reviews of Environmental Contamination and Toxicology, Reviews of Environmental Contamination and Toxicology, 202, Springer, New York, 2010, pp. 1–52.
12. [12]
  O. US EPA, Chemicals under the Toxic Substances Control Act (TSCA), (2015). https://www.epa.gov/chemicals-under-tsca (accessed June 29, 2023).
13. [13]
  Stockholm Convention on Persistent Organic Pollutants (POPs), https://chm.pops.int/TheConvention/POPsReviewCommittee/Meetings/POPRC9/POPRC9Followup/PFOSSubmission/tabid/3565/Default.aspx (accessed June 30, 2023).
14. [14]
  Anon, Candidate list of substances of very high concern for authorisation - ECHA, https://echa.europa.eu/web/guest/candidate-list-table (accessed June 29, 2023).
15. [15]
  Commission Regulation (EU) 2021/1297 of 4 August 2021 amending annex ⅩⅦ to Regulation (EC) No 1907/2006 of the European Parliament and of the Council as regards perfluorocarboxylic acids containing 9 to 14 carbon atoms in the chain (C9-C14 PFCAs), their salts and C9-C14 PFCA-related substances (Text with EEA relevance), 2021. http://data.europa.eu/eli/reg/2021/1297/oj/eng (accessed June 30, 2023).
16. [16]
  A. Maimaiti, S. Deng, P. Meng, et al., Chem. Eng. J. 348 (2018) 494–502. doi: 10.1016/j.cej.2018.05.006
17. [17]
  Y. Bao, J. Niu, Z. Xu, et al., J. Colloid and Interface Sci. 434 (2014) 59–64. doi: 10.1016/j.jcis.2014.07.041
18. [18]
  T.D. Appleman, E.R.V. Dickenson, C. Bellona, C.P. Higgins, J. Hazard. Mater. 260 (2013) 740–746. doi: 10.1016/j.jhazmat.2013.06.033
19. [19]
  K. Tahir, A.S. Ali, J. Kim, et al., Chemosphere 328 (2023) 138584. doi: 10.1016/j.chemosphere.2023.138584
20. [20]
  J. Blotevogel, R.J. Giraud, A.K. Rappé, Chem. Eng. J. 457 (2023) 141235. doi: 10.1016/j.cej.2022.141235
21. [21]
  T. Sidnell, R.J. Wood, J. Hurst, J. Lee, M.J. Bussemaker, Ultrason. Sonochem. 87 (2022) 105944.
22. [22]
  Z. Chen, X. Wang, H. Feng, et al., Environ. Sci. Technol. 56 (2022) 14409–14417. doi: 10.1021/acs.est.2c02906
23. [23]
  J. Cui, P. Gao, Y. Deng, Environ. Sci. Technol. 54 (2020) 3752–3766. doi: 10.1021/acs.est.9b05565
24. [24]
  H. Hori, E. Hayakawa, H. Einaga, Environ. Sci. Technol. 38 (2004) 6118–6124. doi: 10.1021/es049719n
25. [25]
  S. Vaalgamaa, A.V. Vähätalo, N. Perkola, S. Huhtala, Sci. Total Environ. 409 (2011) 3043–3048. doi: 10.1016/j.scitotenv.2011.04.036
26. [26]
  X. Liang, J. Cheng, C. Yang, S. Yang, Chem. Eng. J. 298 (2016) 291–299.
27. [27]
  J. Cheng, X. Liang, S. Yang, Y. Hu, Chem. Eng. J. 239 (2014) 242–249.
28. [28]
  N. Merino, Y. Qu, R.A. Deeb, et al., Environ. Eng. Sci. 33 (2016) 615–649. doi: 10.1089/ees.2016.0233
29. [29]
  F. Li, J. Duan, S. Tian, et al., Chem. Eng. J. 380 (2020) 122506.
30. [30]
  S.C. Panchangam, A.Y.C. Lin, K.L. Shaik, C.F. Lin, Chemosphere 77 (2009) 242–248.
31. [31]
  Z. Cheng, Q. Chen, Z. Liu, Environ. Sci. Technol. Lett. 8 (2021) 645–650. doi: 10.1021/acs.estlett.1c00403
32. [32]
  Y. Zhang, J. Liu, S. Ghoshal, A. Moores, Environ. Sci. Technol. 55 (2021) 16655–16664. doi: 10.1021/acs.est.1c05549
33. [33]
  L. Bai, Y. Jiang, D. Xia, Environ. Sci. Technol. 56 (2022) 624–633. doi: 10.1021/acs.est.1c06356
34. [34]
  Y. Chen, M. Bhati, B.W. Walls, Environ. Sci. Technol. 56 (2022) 8942–8952. doi: 10.1021/acs.est.2c01637
35. [35]
  R. Qu, J. Liu, C. Li, Water Res. 104 (2016) 34–43.
36. [36]
  X. Xin, J. Kim, D.C. Ashley, C.H. Huang, ACS ES&T Water 3 (2023) 2776–2785. doi: 10.1021/acsestwater.3c00274
37. [37]
  M.J.F. Scuseria, G.W. Trucks, H.B. Schlegel, et al., Gaussian 16, revision C.01, 2016.
38. [38]
  T. Lu, F. Chen, J. Comput. Chem. 33 (2012) 580–592. doi: 10.1002/jcc.22885
39. [39]
  Z. Liu, T. Lu, Q. Chen, Carbon 165 (2020) 461–467.
40. [40]
  IBM Corp. (2016). IBM SPSS statistics (Version 24).
41. [41]
  W.H. Fang, R.Z. Liu, X. Zheng, D.L. Phillips, J. Org. Chem. 67 (2002) 8407–8415.
42. [42]
  H. Hori, A. Yamamoto, K. Koike, et al., Chemosphere 68 (2007) 572–578.
43. [43]
  J. Chen, P. Zhang, J. Liu, J. Environ. Sci. 19 (2007) 387–390. doi: 10.1007/s10967-007-0533-2
44. [44]
  R. Nandi, A. Sharma, A. Priya, D. Kumar, Mol. Divers. 29 (2025) 3207–3231. doi: 10.1007/s11030-024-11070-w
45. [45]
  S. Yang, J. Yang, M. Duan, et al., Trans. Tianjin Univ. 30 (2024) 167–177. doi: 10.1007/s12209-024-00387-0
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