Comparative Evaluation of UV-C-Activated Peroxide and Peroxydisulfate for Degradation of a Selected Herbicide
Extensive utilization of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has resulted in contamination of the aquatic environment; this situation requires effective treatment technology. Ultraviolet-based advanced oxidation processes (UV-AOPs) are widely employed for the removal of organic cont...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-05-01
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| Series: | Separations |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2297-8739/12/5/116 |
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| Summary: | Extensive utilization of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has resulted in contamination of the aquatic environment; this situation requires effective treatment technology. Ultraviolet-based advanced oxidation processes (UV-AOPs) are widely employed for the removal of organic contaminants from water. This study’s aim was to compare the degradation of the pesticide 2,4-D in UV-C-activated peroxide and peroxydisulfate systems. UV-C irradiation alone exhibited a negligible effect on pesticide degradation, whereas the addition of oxidants significantly enhanced the degradation efficiency relative to 2,4-D. Complete pesticide removal was achieved after 15 min of UV/H<sub>2</sub>O<sub>2</sub> treatment, while twice as much time was required with the UV/S<sub>2</sub>O<sub>8</sub><sup>2−</sup> process. COD decreased by 74% and 28% for UV-C-activated peroxide and peroxydisulfate, respectively. Both investigated systems demonstrated good performance for 2,4-D dechlorination. Pesticide degradation rates increased with increasing dosages of the applied oxidants. Acidic conditions were more favorable for degradation of 2,4-D, compared to neutral and basic conditions, for both systems studied. The degradation efficiency relative to 2,4-D decreased in the presence of HA, Cl<sup>−</sup> and HCO<sub>3</sub><sup>−</sup> in water matrices. The predominant radical for the UV-C-activated peroxydisulfate was determined to be a sulfate radical. These findings are of fundamental and practical significance in understanding UV-C-activated 2,4-D degradation, paving the way for the selection of preferred processes for the optimal removal of pesticides from various aqueous matrices. |
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| ISSN: | 2297-8739 |