Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications
Abstract Electrochemical methods can detect trace amounts of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the environment to help their management. PFAS adsorption on electrodes is an essential step in these methods, but is poorly understood. Here, we study the adsorption of perfluoroocta...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Wiley-VCH
2023-11-01
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| Series: | ChemElectroChem |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/celc.202300298 |
| _version_ | 1797635959117840384 |
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| author | Xin Wang Seokgyun Ham Hongwei Zhang Prof. Dr. Yun Wang Prof. Dr. Rui Qiao |
| author_facet | Xin Wang Seokgyun Ham Hongwei Zhang Prof. Dr. Yun Wang Prof. Dr. Rui Qiao |
| author_sort | Xin Wang |
| collection | DOAJ |
| description | Abstract Electrochemical methods can detect trace amounts of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the environment to help their management. PFAS adsorption on electrodes is an essential step in these methods, but is poorly understood. Here, we study the adsorption of perfluorooctanoic acid (PFOA), a model PFAS molecule, on gold substrates using metadynamics and equilibrium molecular dynamics simulations. The two‐dimensional free energy landscape obtained from metadynamics reveals that a PFOA molecule can adsorb on a neutral gold surface with the lowest free energy of −83.9 kJ/mol by adopting a co‐planar orientation, indicating a strong enrichment of PFOA occurs near the electrode. Spontaneous adsorption in other configurations, e. g., only a PFOA molecule‘s head attaches to the electrode, also occurs. However, a PFOA molecule generally must overcome energy barriers to become adsorbed. We show that energetic effects, particularly those associated with van der Waals PFOA‐gold interactions, are the primary driver for PFOA adsorption, and entropic effects associated with interfacial water molecules are the secondary driver. The implications of these results for the electrochemical detection and analysis of PFAS molecules are discussed. |
| first_indexed | 2024-03-11T12:28:28Z |
| format | Article |
| id | doaj.art-382fed081c314fa0b0c9b03a8f40e23b |
| institution | Directory Open Access Journal |
| issn | 2196-0216 |
| language | English |
| last_indexed | 2024-03-11T12:28:28Z |
| publishDate | 2023-11-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | ChemElectroChem |
| spelling | doaj.art-382fed081c314fa0b0c9b03a8f40e23b2023-11-06T04:46:43ZengWiley-VCHChemElectroChem2196-02162023-11-011021n/an/a10.1002/celc.202300298Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical ApplicationsXin Wang0Seokgyun Ham1Hongwei Zhang2Prof. Dr. Yun Wang3Prof. Dr. Rui Qiao4Department of Mechanical Engineering Virginia Tech Blacksburg VA 24061 USADepartment of Mechanical Engineering Virginia Tech Blacksburg VA 24061 USADepartment of Mechanical Engineering Virginia Tech Blacksburg VA 24061 USACentre for Catalysis and Clean Energy School of Environment and Science Griffith University Gold Coast Campus Southport QLD 4222 AustraliaDepartment of Mechanical Engineering Virginia Tech Blacksburg VA 24061 USAAbstract Electrochemical methods can detect trace amounts of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in the environment to help their management. PFAS adsorption on electrodes is an essential step in these methods, but is poorly understood. Here, we study the adsorption of perfluorooctanoic acid (PFOA), a model PFAS molecule, on gold substrates using metadynamics and equilibrium molecular dynamics simulations. The two‐dimensional free energy landscape obtained from metadynamics reveals that a PFOA molecule can adsorb on a neutral gold surface with the lowest free energy of −83.9 kJ/mol by adopting a co‐planar orientation, indicating a strong enrichment of PFOA occurs near the electrode. Spontaneous adsorption in other configurations, e. g., only a PFOA molecule‘s head attaches to the electrode, also occurs. However, a PFOA molecule generally must overcome energy barriers to become adsorbed. We show that energetic effects, particularly those associated with van der Waals PFOA‐gold interactions, are the primary driver for PFOA adsorption, and entropic effects associated with interfacial water molecules are the secondary driver. The implications of these results for the electrochemical detection and analysis of PFAS molecules are discussed.https://doi.org/10.1002/celc.202300298AdsorptionGoldMetadynamicsMolecular dynamicsPerfluoroalkyl and polyfluoroalkyl substances (PFAS) |
| spellingShingle | Xin Wang Seokgyun Ham Hongwei Zhang Prof. Dr. Yun Wang Prof. Dr. Rui Qiao Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications ChemElectroChem Adsorption Gold Metadynamics Molecular dynamics Perfluoroalkyl and polyfluoroalkyl substances (PFAS) |
| title | Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications |
| title_full | Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications |
| title_fullStr | Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications |
| title_full_unstemmed | Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications |
| title_short | Adsorption of Model Polyfluoroalkyl Substances on Gold Electrodes for Electroanalytical Applications |
| title_sort | adsorption of model polyfluoroalkyl substances on gold electrodes for electroanalytical applications |
| topic | Adsorption Gold Metadynamics Molecular dynamics Perfluoroalkyl and polyfluoroalkyl substances (PFAS) |
| url | https://doi.org/10.1002/celc.202300298 |
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