Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced Bioremediation
This study presents a comprehensive kinetic analysis of sulfamethoxazole (SMX) degradation by the photo-Fenton process, highlighting its potential for removing emerging micropollutants in water treatment. The degradation of SMX followed pseudo-first-order kinetics, with increasing Fe(II) concentrati...
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2025-04-01
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| author | Unai Duoandicoechea Elisabeth Bilbao-García Natalia Villota |
| author_facet | Unai Duoandicoechea Elisabeth Bilbao-García Natalia Villota |
| author_sort | Unai Duoandicoechea |
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| description | This study presents a comprehensive kinetic analysis of sulfamethoxazole (SMX) degradation by the photo-Fenton process, highlighting its potential for removing emerging micropollutants in water treatment. The degradation of SMX followed pseudo-first-order kinetics, with increasing Fe(II) concentrations significantly accelerating the oxidation rate. A kinetic model was developed to describe SMX removal, aromaticity loss, and color changes during treatment. Although SMX was rapidly eliminated, intermediate aromatic and chromophoric compounds persisted, requiring extended reaction times for complete mineralization. The kinetic modeling of aromaticity and color revealed distinct degradation pathways and rate constants, showing a strong dependence on iron dosage. The formation of nitrate and sulfate was used to monitor nitrogen and sulfur mineralization, respectively. Optimal nitrate formation was achieved at 22 mol SMX: 1 mol Fe(II), beyond which excessive iron promoted radical scavenging and the formation of stable Fe–aminophenol complexes, inhibiting complete nitrogen oxidation and aromatic degradation. Moreover, excessive Fe(II) led to increased water coloration due to complexation with partially oxidized aromatic byproducts. These findings emphasize the need for optimized catalyst dosing to balance degradation efficiency and minimize secondary effects. The proposed kinetic models offer a predictive tool for improving photo-Fenton-based treatments and integrating them with biological processes to enhance micropollutant bioremediation. |
| format | Article |
| id | doaj-art-62c650d8eceb4c42881500ca9717df2d |
| institution | DOAJ |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-04-01 |
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| spelling | doaj-art-62c650d8eceb4c42881500ca9717df2d2025-08-20T03:14:20ZengMDPI AGApplied Sciences2076-34172025-04-01158453110.3390/app15084531Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced BioremediationUnai Duoandicoechea0Elisabeth Bilbao-García1Natalia Villota2Department of Environmental and Chemical Engineering, Faculty of Engineering Vitoria-Gasteiz, University of the Basque Country UPV/EHU, 01006 Vitoria-Gasteiz, SpainDepartment of Environmental and Chemical Engineering, Bilbao School of Engineering, University of the Basque Country UPV/EHU, 48013 Bilbao, SpainDepartment of Environmental and Chemical Engineering, Faculty of Engineering Vitoria-Gasteiz, University of the Basque Country UPV/EHU, 01006 Vitoria-Gasteiz, SpainThis study presents a comprehensive kinetic analysis of sulfamethoxazole (SMX) degradation by the photo-Fenton process, highlighting its potential for removing emerging micropollutants in water treatment. The degradation of SMX followed pseudo-first-order kinetics, with increasing Fe(II) concentrations significantly accelerating the oxidation rate. A kinetic model was developed to describe SMX removal, aromaticity loss, and color changes during treatment. Although SMX was rapidly eliminated, intermediate aromatic and chromophoric compounds persisted, requiring extended reaction times for complete mineralization. The kinetic modeling of aromaticity and color revealed distinct degradation pathways and rate constants, showing a strong dependence on iron dosage. The formation of nitrate and sulfate was used to monitor nitrogen and sulfur mineralization, respectively. Optimal nitrate formation was achieved at 22 mol SMX: 1 mol Fe(II), beyond which excessive iron promoted radical scavenging and the formation of stable Fe–aminophenol complexes, inhibiting complete nitrogen oxidation and aromatic degradation. Moreover, excessive Fe(II) led to increased water coloration due to complexation with partially oxidized aromatic byproducts. These findings emphasize the need for optimized catalyst dosing to balance degradation efficiency and minimize secondary effects. The proposed kinetic models offer a predictive tool for improving photo-Fenton-based treatments and integrating them with biological processes to enhance micropollutant bioremediation.https://www.mdpi.com/2076-3417/15/8/4531sulfamethoxazolephoto-Fenton processkinetic modelingaromaticity degradationcolor removalnitrate and sulfate formation |
| spellingShingle | Unai Duoandicoechea Elisabeth Bilbao-García Natalia Villota Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced Bioremediation Applied Sciences sulfamethoxazole photo-Fenton process kinetic modeling aromaticity degradation color removal nitrate and sulfate formation |
| title | Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced Bioremediation |
| title_full | Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced Bioremediation |
| title_fullStr | Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced Bioremediation |
| title_full_unstemmed | Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced Bioremediation |
| title_short | Kinetic Modeling of Sulfamethoxazole Degradation by Photo-Fenton: Tracking Color Development and Iron Complex Formation for Enhanced Bioremediation |
| title_sort | kinetic modeling of sulfamethoxazole degradation by photo fenton tracking color development and iron complex formation for enhanced bioremediation |
| topic | sulfamethoxazole photo-Fenton process kinetic modeling aromaticity degradation color removal nitrate and sulfate formation |
| url | https://www.mdpi.com/2076-3417/15/8/4531 |
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