Kinetics and mechanism of Paraquat’s degradation: UV-C photolysis vs UV-C photocatalysis with TiO₂ /SiC foams

Marien, Cédric B. D., Le Pivert, Marie, Azaïs, Antonin, M’Bra, Ignace Christian, Drogui, Patrick ORCID: https://orcid.org/0000-0002-3802-2729, Dirany, Ahmad et Robert, Didier (2019). Kinetics and mechanism of Paraquat’s degradation: UV-C photolysis vs UV-C photocatalysis with TiO₂ /SiC foams Journal of Hazardous Materials , vol. 370 . p. 164-171. DOI: 10.1016/j.jhazmat.2018.06.009.

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Résumé

In this study, the photolytic and photocatalytic removal of the herbicide paraquat is investigated under UV-C (254 nm). For photocatalytic experiments, SiC foams were used with P25-TiO₂ nanoparticles deposited by dip-coating. The foams were characterized by scanning electron microscopy and paraquat’s degradation under UV-C photolysis or photocatalysis, followed by UV–vis spectroscopy, total organic carbon analyzer, LC–MS and ion chromatography. After 3 h of reactions by photolysis and photocatalysis, 4% and 91% of TOC removal were observed. An analysis of degradation by-products showed a similar degradation pathway with pyridinium ions observed by LC/MS and carboxylic acids (succinate, acetate, oxalate and formate) detected by ion chromatography. In conclusion, these two different photo-degradation processes are able to remove paraquat and produce similar by-products. However, the kinetics of degradation is rather slow during photolysis and it is recommended to combine the UV-C lightning with a TiO₂ photocatalyst to improve the mineralization rate.

Type de document:	Article
Mots-clés libres:	advanced oxidation process; photocatalysis; photolysis; TiO₂; SiC foam
Centre:	Centre Eau Terre Environnement
Date de dépôt:	27 août 2018 20:36
Dernière modification:	15 févr. 2022 15:58
URI:	https://espace.inrs.ca/id/eprint/7303

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