| Autor: |
da Costa EP; Departament of Sanitary and Environmental Engineering, Research Group on Environmental Applications of Advanced Oxidation Processes, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil., Bottrel SEC; Departament of Sanitary and Environmental Engineering, Universidade Federal de Juiz de Fora, Av. José Lourenço Kelmer, Juiz de Fora, 36036-900, Brazil., Starling MCVM; Departament of Sanitary and Environmental Engineering, Research Group on Environmental Applications of Advanced Oxidation Processes, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil., Leão MMD; Departament of Sanitary and Environmental Engineering, Research Group on Environmental Applications of Advanced Oxidation Processes, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil., Amorim CC; Departament of Sanitary and Environmental Engineering, Research Group on Environmental Applications of Advanced Oxidation Processes, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, Minas Gerais, 31270-901, Brazil. camila@desa.ufmg.br. |
| Abstrakt: |
This study aimed at investigating the degradation of fungicide carbendazim (CBZ) via photo-Fenton reactions in artificially and solar irradiated photoreactors at laboratory scale and in a semi-pilot scale Raceway Pond Reactor (RPR), respectively. Acute toxicity was monitored by assessing the sensibility of bioluminescent bacteria (Aliivibrio fischeri) to samples taken during reactions. In addition, by-products formed during solar photo-Fenton were identified by liquid chromatography coupled to mass spectrometry (UFLC-MS). For tests performed in lab-scale, two artificial irradiation sources were compared (UV λ > 254nm and UV-Vis λ > 320nm ). A complete design of experiments was performed in the semi-pilot scale RPR in order to optimize reaction conditions (Fe 2+ and H 2 O 2 concentrations, and water depth). Efficient degradation of carbendazim (> 96%) and toxicity removal were achieved via artificially irradiated photo-Fenton under both irradiation sources. Control experiments (UV photolysis and UV-Vis peroxidation) were also efficient but led to increased acute toxicity. In addition, H 2 O 2 /UV λ > 254nm required longer reaction time (60 minutes) when compared to the photo-Fenton process (less than 1 min). While Fenton's reagent achieved high CBZ and acute toxicity removal, its efficiency demands higher concentration of reagents in comparison to irradiated processes. Solar photo-Fenton removed carbendazim within 15 min of reaction (96%, 0.75 kJ L -1 ), and monocarbomethoxyguanidine, benzimidazole isocyanate, and 2-aminobenzimidazole were identified as transformation products. Results suggest that both solar photo-Fenton and artificially irradiated systems are promising routes for carbendazim degradation. |
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