pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse Systems
Diclofenac (DCF), a widely consumed non-steroidal anti-inflammatory drug, presents significant environmental challenges due to its persistence and toxicity in aquatic ecosystems. This study investigates the pH-dependent ozonation of DCF in aqueous media, focusing on degradation kinetics, transformat...
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MDPI AG
2025-06-01
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| author | Natalia Villota Unai Duoandicoechea Enzo Valentin Tosi-Zarate |
| author_facet | Natalia Villota Unai Duoandicoechea Enzo Valentin Tosi-Zarate |
| author_sort | Natalia Villota |
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| description | Diclofenac (DCF), a widely consumed non-steroidal anti-inflammatory drug, presents significant environmental challenges due to its persistence and toxicity in aquatic ecosystems. This study investigates the pH-dependent ozonation of DCF in aqueous media, focusing on degradation kinetics, transformation pathways, and effects on key water quality indicators. Ozonation experiments were conducted across a broad pH range (2.0–13.0), using a multi-scale analytical approach combining UV/Vis spectroscopy, colorimetry, turbidity, and aromaticity measurements. The results show that pH strongly influences DCF degradation efficiency: acidic conditions favor selective reactions with molecular ozone, while an alkaline pH enhances non-selective oxidation via hydroxyl radicals. Spectroscopic analyses revealed the progressive breakdown of aromatic structures, the transient formation of quinonoid and phenolic intermediates, and eventual mineralization to inorganic by-products such as nitrate. Low-pH conditions also induced turbidity due to precipitation of neutral DCF species. These findings underline the importance of pH control in optimizing ozonation performance and minimizing toxic by-products. Furthermore, this study proposes ozonation as a viable pre-treatment step within Nature-Based Solutions (NBSs), potentially improving the performance of downstream biological systems such as constructed wetlands. The results contribute to the development of integrated and sustainable water treatment strategies for pharmaceutical contaminant removal and water reuse. |
| format | Article |
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| institution | Kabale University |
| issn | 2571-8797 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | MDPI AG |
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| series | Clean Technologies |
| spelling | doaj-art-e9f882ad38c9485c943200032cb6d83a2025-08-20T03:26:21ZengMDPI AGClean Technologies2571-87972025-06-01724710.3390/cleantechnol7020047pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse SystemsNatalia Villota0Unai Duoandicoechea1Enzo Valentin Tosi-Zarate2Department of Environmental and Chemical Engineering, Faculty of Engineering Vitoria-Gasteiz, University of the Basque Country UPV/EHU, Nieves Cano 12, 01006 Vitoria-Gasteiz, SpainDepartment of Environmental and Chemical Engineering, Faculty of Engineering Vitoria-Gasteiz, University of the Basque Country UPV/EHU, Nieves Cano 12, 01006 Vitoria-Gasteiz, SpainDepartment of Environmental and Chemical Engineering, Faculty of Engineering Vitoria-Gasteiz, University of the Basque Country UPV/EHU, Nieves Cano 12, 01006 Vitoria-Gasteiz, SpainDiclofenac (DCF), a widely consumed non-steroidal anti-inflammatory drug, presents significant environmental challenges due to its persistence and toxicity in aquatic ecosystems. This study investigates the pH-dependent ozonation of DCF in aqueous media, focusing on degradation kinetics, transformation pathways, and effects on key water quality indicators. Ozonation experiments were conducted across a broad pH range (2.0–13.0), using a multi-scale analytical approach combining UV/Vis spectroscopy, colorimetry, turbidity, and aromaticity measurements. The results show that pH strongly influences DCF degradation efficiency: acidic conditions favor selective reactions with molecular ozone, while an alkaline pH enhances non-selective oxidation via hydroxyl radicals. Spectroscopic analyses revealed the progressive breakdown of aromatic structures, the transient formation of quinonoid and phenolic intermediates, and eventual mineralization to inorganic by-products such as nitrate. Low-pH conditions also induced turbidity due to precipitation of neutral DCF species. These findings underline the importance of pH control in optimizing ozonation performance and minimizing toxic by-products. Furthermore, this study proposes ozonation as a viable pre-treatment step within Nature-Based Solutions (NBSs), potentially improving the performance of downstream biological systems such as constructed wetlands. The results contribute to the development of integrated and sustainable water treatment strategies for pharmaceutical contaminant removal and water reuse.https://www.mdpi.com/2571-8797/7/2/47ozonationdiclofenac degradationadvanced oxidation processespH-dependent transformationpharmaceutical pollutantswater quality |
| spellingShingle | Natalia Villota Unai Duoandicoechea Enzo Valentin Tosi-Zarate pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse Systems Clean Technologies ozonation diclofenac degradation advanced oxidation processes pH-dependent transformation pharmaceutical pollutants water quality |
| title | pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse Systems |
| title_full | pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse Systems |
| title_fullStr | pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse Systems |
| title_full_unstemmed | pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse Systems |
| title_short | pH-Dependent Ozonation of Diclofenac: Molecular Insights and Implications for Water Quality and Nature-Based Water Reuse Systems |
| title_sort | ph dependent ozonation of diclofenac molecular insights and implications for water quality and nature based water reuse systems |
| topic | ozonation diclofenac degradation advanced oxidation processes pH-dependent transformation pharmaceutical pollutants water quality |
| url | https://www.mdpi.com/2571-8797/7/2/47 |
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