TY - JOUR
T1 - Kinetics and mechanism of thiamethoxam abatement by ozonation and ozone-based advanced oxidation processes
AU - Wang, Huijiao
AU - Zhan, Juhong
AU - Gao, Lingwei
AU - Yu, Gang
AU - Komarneni, Sridhar
AU - Wang, Yujue
N1 - Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2020/5/15
Y1 - 2020/5/15
N2 - In this study, the abatement of neonicotinoid insecticide, thiamethoxam, by single ozonation, ozone/ultraviolet (O3/UV) and electro-peroxone (EP) process was evaluated. The second-order rate constants for the reaction of thiamethoxam with O3 and hydroxyl radical ([rad]OH) at pH 7 were determined to be 15.4 M–1 s–1 and 3.9 × 109 M–1 s–1, respectively. The degradation pathways of thiamethoxam were proposed based on quantum chemical calculations and transformation products were identified using chromatographic and mass-spectrometric techniques. The acute and chronic toxicity of thiamethoxam and its major TPs to various aquatic organisms were assessed. With typical ozone doses applied in water treatment (≤5 mg/L), thiamethoxam was abated by only ∼16–32 % in two real water matrices (groundwater and surface water) during single ozonation, but by ∼100 % and >70 % during the O3/UV and EP treatment, respectively. The energy demand to abate 90 % thiamethoxam in the two water matrices was generally comparable for single ozonation and the EP process (∼0.14 ± 0.03 kW h/m3), but higher for the O3/UV process (0.21–0.22 kW h/m3). These results suggest that single ozonation is unable to sufficiently abate thiamethoxam under typical conditions of water treatment. Therefore, ozone-based advanced oxidation processes are needed to enhance thiamethoxam abatement.
AB - In this study, the abatement of neonicotinoid insecticide, thiamethoxam, by single ozonation, ozone/ultraviolet (O3/UV) and electro-peroxone (EP) process was evaluated. The second-order rate constants for the reaction of thiamethoxam with O3 and hydroxyl radical ([rad]OH) at pH 7 were determined to be 15.4 M–1 s–1 and 3.9 × 109 M–1 s–1, respectively. The degradation pathways of thiamethoxam were proposed based on quantum chemical calculations and transformation products were identified using chromatographic and mass-spectrometric techniques. The acute and chronic toxicity of thiamethoxam and its major TPs to various aquatic organisms were assessed. With typical ozone doses applied in water treatment (≤5 mg/L), thiamethoxam was abated by only ∼16–32 % in two real water matrices (groundwater and surface water) during single ozonation, but by ∼100 % and >70 % during the O3/UV and EP treatment, respectively. The energy demand to abate 90 % thiamethoxam in the two water matrices was generally comparable for single ozonation and the EP process (∼0.14 ± 0.03 kW h/m3), but higher for the O3/UV process (0.21–0.22 kW h/m3). These results suggest that single ozonation is unable to sufficiently abate thiamethoxam under typical conditions of water treatment. Therefore, ozone-based advanced oxidation processes are needed to enhance thiamethoxam abatement.
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U2 - 10.1016/j.jhazmat.2020.122180
DO - 10.1016/j.jhazmat.2020.122180
M3 - Article
C2 - 32006850
AN - SCOPUS:85078475829
SN - 0304-3894
VL - 390
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 122180
ER -