Quantification of perfluorooctanoic acid decomposition mechanism applying negative voltage to anode during photoelectrochemical process
| Autor: | Yongyue Zhou, Yonghyeon Lee, Mingcan Cui, Yangmin Ren, Jeehyeong Khim |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Anatase
Environmental Engineering Materials science Health Toxicology and Mutagenesis 0208 environmental biotechnology Inorganic chemistry 02 engineering and technology Electrolyte 010501 environmental sciences 01 natural sciences Redox law.invention chemistry.chemical_compound law Environmental Chemistry Photoelectrochemical process Electrodes 0105 earth and related environmental sciences Fluorocarbons Public Health Environmental and Occupational Health General Medicine General Chemistry Pollution Decomposition Cathode 020801 environmental engineering Anode chemistry Perfluorooctanoic acid Caprylates Oxidation-Reduction |
| Zdroj: | Chemosphere. 284:131311 |
| ISSN: | 0045-6535 |
| DOI: | 10.1016/j.chemosphere.2021.131311 |
| Popis: | Perfluorooctanoic acid (PFOA) is a carcinogen with a high binding energy between fluorine and carbon and is symmetrically linked, making it difficult to treat. In this study, a self-doped TiO2 nanotube array (TNTA) was used as the anode and platinum as the cathode to quantify the PFOA removal mechanism using a photoelectrochemical (PEC) system. The external voltage was negative compared to that of the anode. In addition, NO3− and t-BuOH were used as scavengers to quantify the PFOA oxidation/reduction mechanism in the PEC system. As a result of the study, TNTA crystals are TiO2 anatase, and the band gap energy was 3.42. The synergy index of PEC was 1.25, and the best electrolyte was SO42−. The PFOA decomposition activation energy corresponds to 70.84 kJ mol−1. Moreover, ΔH# and ΔS# correspond to 68.34 kJ mol−1 and 0.190 kJ mol−1 K−1, respectively. When the external negative voltage was 1 V, the contributions of the oxidation/reduction reaction during PFOA decomposition were 60% and 40%, and when the external negative voltage was 5 V, the contributions of the redox reaction were 45% and 55%. As the external negative voltage increased, the contribution of the reduction reaction increased as the number of electrons applied to the anode increased. When PFOA was decomposed, the by-products were C7F13O2H, C6F11O2H, C5F9O2H, and C4F7O2H, respectively. This study is expected to be used as basic data for research on the effects of other factors on the oxidation/reduction as well as the selection of anode and cathode materials on the decomposition of pollutants other than PFOA when using a PEC system. |
| Databáze: | OpenAIRE |
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