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Degradation and mechanism of 2,4-dichlorophenoxyacetic acid (2,4-D) by thermally activated persulfate oxidation

Cai, Jingju and Zhou, Minghua and Yang, Weilu and Pan, Yuwei and Lu, Xiaoye and Groenen Serrano, Karine Degradation and mechanism of 2,4-dichlorophenoxyacetic acid (2,4-D) by thermally activated persulfate oxidation. (2018) Chemosphere, 212. 784-793. ISSN 0045-6535

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Official URL: https://doi.org/10.1016/j.chemosphere.2018.08.127

Abstract

The chlorinated phenoxy herbicide of 2,4-dichlorophenoxyacetic acid (2,4-D) was oxidized by thermally activated persulfate (TAP). This herbicide was studied for different persulfate dosages (0.97–7.29 g L−1), for varying initial pH levels (3–12) and temperatures (25–70 °C). Compared with Fe2+/PS, TAP could achieve a higher total organic carbon (TOC) removal under wider pH ranges of 3–12. Increasing the mole ratio of PS to 2,4-D favored for the decay of 2,4-D and the best performance was achieved at the ratio of 50. The 2,4-D degradation rate constant highly depended on the initial pH and temperature, in accordance with the Arrhenius model, with an apparent activation energy of 135.24 kJ mol−1. The study of scavenging radicals and the EPR confirmed the presence of both SO4− and OH. However, SO4− was the predominant oxidation radical for 2,4-D decay. The presence of both Cl− and CO32− inhibited the degradation of 2,4-D, whereas the effect of NO3− could be negligible. Verified by GC/MS, HPLC and ion chromatography, a possible degradation mechanism was proposed

Item Type:Article
HAL Id:hal-01957076
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - INPT (FRANCE)
Other partners > Nankai University - NKU (CHINA)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UPS (FRANCE)
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Deposited By: Loetitia MOYA
Deposited On:17 Dec 2018 08:55

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