A review on pyrolysis and defluorination mechanisms of perfluoroalkyl substances （PFASs）

SHAO Heng; CHENG Zikun; CAO Runzi; YI Meiling; XU Shuang; LI Yang

doi:10.13205/j.hjgc.202508004

Volume 43 Issue 8

Aug. 2025

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SHAO Heng, CHENG Zikun, CAO Runzi, YI Meiling, XU Shuang, LI Yang. A review on pyrolysis and defluorination mechanisms of perfluoroalkyl substances （PFASs）[J]. ENVIRONMENTAL ENGINEERING , 2025, 43(8): 49-59. doi: 10.13205/j.hjgc.202508004

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SHAO Heng, CHENG Zikun, CAO Runzi, YI Meiling, XU Shuang, LI Yang. A review on pyrolysis and defluorination mechanisms of perfluoroalkyl substances （PFASs）[J]. ENVIRONMENTAL ENGINEERING , 2025, 43(8): 49-59. doi: 10.13205/j.hjgc.202508004

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A review on pyrolysis and defluorination mechanisms of perfluoroalkyl substances （PFASs）

doi: 10.13205/j.hjgc.202508004

SHAO Heng^1,2,3,
CHENG Zikun^1,2,3,
CAO Runzi^1,2,3,
YI Meiling^1,2,3,
XU Shuang^1,2,3,
LI Yang^{1,2,3
,
,}

1. School of Environment, Beijing Normal University, Beijing 100875, China;
2. Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing 100875, China;
3. State Key Laboratory of Regional Environment and Sustainability, Beijing 100875, China

Received Date: 2025-06-28
Accepted Date: 2025-07-30
Rev Recd Date: 2025-07-15

Abstract

Abstract

Perfluoroalkyl substances （PFASs） are widely used in industrial fields and daily life due to their high chemical stability. They exhibit high biological toxicity and persistence and have become a typical persistent organic pollutant with global concern. The highly stable carbon-fluorine bonds in PFASs make them difficult to degrade completely by conventional methods. Pyrolysis technology has become an important approach for degrading PFASs due to its efficient cracking of C—F and C—C bonds and low operating cost. This review summarizes the effects of PFASs’ intrinsic physical and chemical properties （functional groups and chain lengths） and reaction conditions （temperature， atmosphere， and catalysts） on their pyrolysis. It was found that the lower the thermal stability of the functional group itself， the lower the pyrolysis temperature of PFASs； similarly， longer chain lengths also resulted in lower pyrolysis temperatures. As the temperature increased， the degradation efficiency and defluorination rate of PFASs improved， and the required pyrolysis time decreased. Oxygen and water vapor were observed to accelerate the oxidative decomposition of PFASs. Activated carbon and aluminum/copper oxides reduced the pyrolysis temperature of PFASs through adsorption， thereby promoting low-temperature decomposition. Calcium/sodium-based catalysts improved the defluorination efficiency of PFASs and reduce the formation of volatile organic fluorine products. Furthermore， this review outlines the reaction pathways of PFASs pyrolysis， which mainly include three stages： removal of head functional groups， carbon chain scission， and the formation of short-chain perfluorocarbons and inorganic fluorides. Finally， this paper emphasizes that achieving complete and harmless treatment of PFASs requires further in-depth exploration of the molecular dynamics mechanisms underlying PFASs degradation， optimization of catalysts， and control of the formation of short-chain perfluorocarbons. This review aims to provide a theoretical basis and technical support for the treatment of PFASs-containing solid waste， ultimately achieving the goal of harmless treatment of PFASs.
- perfluoroalkyl substances,
- pyrolysis mechanisms,
- defluorination efficiency,
- influencing factors,
- reaction pathways

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References(61)

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