Physical and chemical behavior of 'Permanent chemical' PFOA and its substitute GenX at the air-water interface: A systematic review
6 affiliations
- 1State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
- 2State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Corresponding author.
- 3Institute of Hematology, Senior Department of Hematology, The Fifth Medical Center of Chinese PLA General, Beijing, 100071, China
- 4Cangzhou Central Hospital, Cangzhou, Hebei, 061000, China
- 5State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China
- 6College of Resources and Environmental Engineering, Guizhou University, Guiyang, 550025, China
Abstract
As one of the representative emerging contaminants (ECs), perfluorooctanoic acid (PFOA) is facing global prohibitions due to its environmental persistence and biological toxicity. Consequently, hexafluoropropylene oxide dimer acid, commonly known as GenX, has been widely used since its introduction as a major substitute for PFOA. However, its high potential of long-distance transport and low degradation rate result in a continuous accumulation, raising significant environmental and health concerns. During the transport, enrichment, and transformation processes of PFOA and GenX, air-water interface (AWI) serves as a critical medium with its contribution to their environmental fate remaining insufficiently characterized. This review systematically compares the adsorption and degradation behavior of PFOA and GenX at the AWI. The AWI adsorption capacity of PFOA and GenX is closely related to molecular structure, especially chain length. Meanwhile, ionic strength and types in the solution are also important factors. Compared with the AWI of bulk water, the microdroplet AWI significantly accelerates PFOA degradation through interfacial reactive species, including hydroxyl radicals (•OH), hydrated electrons (e aq − ), and superoxide radicals (O 2 • − ), involving one- and two-carbon degradation mechanism, S N 2 mechanism and reductive defluorination mechanism (H/F exchange and DHEH pathways). Interfacial environments, including microdroplet size, inorganic ions, pH, and mineral particles, together with external conditions such as gas sparging, ultraviolet irradiation and plasma, regulate not only the degradation kinetics but also reactive-species chemistry, pathway selectivity, and the fate of degradation products. To date, studies on GenX degradation are still limited to aqueous phase, leaving a critical knowledge gap regarding its degradation at the AWI. The present review establishes a theoretical comparison for PFOA and GenX interfacial behavior, highlights the importance of AWI in evaluating the environmental fate and biological risks of PFAS substitutes, offering support for their risk assessment and regulatory control.
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BibTeX
@article{zhang2026physical,
title = {{Physical and chemical behavior of 'Permanent chemical' PFOA and its substitute GenX at the air-water interface: A systematic review}},
author = {Xintong Zhang and Haijie Zhang and Yang Zeng and Tiejun Li and Rui Gao and Junling Li and Yanqin Ren and Fang Bi and Jinjuan Li and Hong Li and Yisheng Xu},
journal = {Emerging Contaminants},
year = {2026},
month = oct,
doi = {10.1016/j.emcon.2026.100768},
url = {https://doi.org/10.1016/j.emcon.2026.100768},
note = {CC BY},
}
RIS
TY - JOUR
TI - Physical and chemical behavior of 'Permanent chemical' PFOA and its substitute GenX at the air-water interface: A systematic review
AU - Xintong Zhang
AU - Haijie Zhang
AU - Yang Zeng
AU - Tiejun Li
AU - Rui Gao
AU - Junling Li
AU - Yanqin Ren
AU - Fang Bi
AU - Jinjuan Li
AU - Hong Li
AU - Yisheng Xu
PY - 2026
DA - 2026/10/31
JO - Emerging Contaminants
DO - 10.1016/j.emcon.2026.100768
UR - https://doi.org/10.1016/j.emcon.2026.100768
AB - As one of the representative emerging contaminants (ECs), perfluorooctanoic acid (PFOA) is facing global prohibitions due to its environmental persistence and biological toxicity. Consequently, hexafluoropropylene oxide dimer acid, commonly known as GenX, has been widely used since its introduction as a major substitute for PFOA. However, its high potential of long-distance transport and low degradation rate result in a continuous accumulation, raising significant environmental and health concerns. During the transport, enrichment, and transformation processes of PFOA and GenX, air-water interface (AWI) serves as a critical medium with its contribution to their environmental fate remaining insufficiently characterized. This review systematically compares the adsorption and degradation behavior of PFOA and GenX at the AWI. The AWI adsorption capacity of PFOA and GenX is closely related to molecular structure, especially chain length. Meanwhile, ionic strength and types in the solution are also important factors. Compared with the AWI of bulk water, the microdroplet AWI significantly accelerates PFOA degradation through interfacial reactive species, including hydroxyl radicals (•OH), hydrated electrons (e aq − ), and superoxide radicals (O 2 • − ), involving one- and two-carbon degradation mechanism, S N 2 mechanism and reductive defluorination mechanism (H/F exchange and DHEH pathways). Interfacial environments, including microdroplet size, inorganic ions, pH, and mineral particles, together with external conditions such as gas sparging, ultraviolet irradiation and plasma, regulate not only the degradation kinetics but also reactive-species chemistry, pathway selectivity, and the fate of degradation products. To date, studies on GenX degradation are still limited to aqueous phase, leaving a critical knowledge gap regarding its degradation at the AWI. The present review establishes a theoretical comparison for PFOA and GenX interfacial behavior, highlights the importance of AWI in evaluating the environmental fate and biological risks of PFAS substitutes, offering support for their risk assessment and regulatory control.
SN - 2405-6650
ER -