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Mechanistic investigation of humic substances assisted photodegradation of imipramine under simulated sunlight. / Pozdnyakov, Ivan P.; Tyutereva, Yuliya E.; Parkhats, Marina V. et al.
In: Science of the Total Environment, Vol. 738, 140298, 10.10.2020.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Mechanistic investigation of humic substances assisted photodegradation of imipramine under simulated sunlight
AU - Pozdnyakov, Ivan P.
AU - Tyutereva, Yuliya E.
AU - Parkhats, Marina V.
AU - Grivin, Vyacheslav P.
AU - Fang, Yuan
AU - Liu, Lu
AU - Wan, Dong
AU - Luo, Fan
AU - Chen, Yong
N1 - Publisher Copyright: © 2020 Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/10/10
Y1 - 2020/10/10
N2 - Imipramine (IMI) is a frequently prescribed tricyclic antidepressant and widely detected in the natural waters, while the environmental fate of IMI is yet poorly understood. Here, we investigated the photodegradation of IMI under simulated sunlight in the presence of humic substances (HS), typically including humic acid (HA) and fulvic acid (FA). The direct and indirect IMI photodegradation was found to increase both with increasing pH and with deoxygenation of the reaction solutions. The excited triplet state of HS (3HS⁎) was mainly responsible for the photosensitized degradation of IMI according to the steady-state quenching and direct time-resolved experiments. The electron transfer interaction between 3HS⁎ and IMI was observed by laser flash photolysis (LFP) with bimolecular reaction rate constants of (4.9 ± 0.4) × 109 M−1 s−1. Evidence of electron transfer from IMI to 3HS⁎ was further demonstrated by the photoproduct analysis. The indirect photodegradation was triggered off in the side chain of IMI with the nonbonding nitrogen electron transferring to 3HS⁎, followed by hydroxylation, demethylation and cleavage of the side chain. Very important that HS photosystem does not lose its efficiency with decreasing of IMI concentration, meaning that the studied photosystem still be used at environmentally relevant concentrations of IMI. These results suggest that photodegradation could be an important attenuation pathway for IMI in HS-rich and anaerobic natural waters.
AB - Imipramine (IMI) is a frequently prescribed tricyclic antidepressant and widely detected in the natural waters, while the environmental fate of IMI is yet poorly understood. Here, we investigated the photodegradation of IMI under simulated sunlight in the presence of humic substances (HS), typically including humic acid (HA) and fulvic acid (FA). The direct and indirect IMI photodegradation was found to increase both with increasing pH and with deoxygenation of the reaction solutions. The excited triplet state of HS (3HS⁎) was mainly responsible for the photosensitized degradation of IMI according to the steady-state quenching and direct time-resolved experiments. The electron transfer interaction between 3HS⁎ and IMI was observed by laser flash photolysis (LFP) with bimolecular reaction rate constants of (4.9 ± 0.4) × 109 M−1 s−1. Evidence of electron transfer from IMI to 3HS⁎ was further demonstrated by the photoproduct analysis. The indirect photodegradation was triggered off in the side chain of IMI with the nonbonding nitrogen electron transferring to 3HS⁎, followed by hydroxylation, demethylation and cleavage of the side chain. Very important that HS photosystem does not lose its efficiency with decreasing of IMI concentration, meaning that the studied photosystem still be used at environmentally relevant concentrations of IMI. These results suggest that photodegradation could be an important attenuation pathway for IMI in HS-rich and anaerobic natural waters.
KW - Electron transfer interaction
KW - Humic substances
KW - Imipramine
KW - Photoproducts
KW - Photosensitization
KW - AQUEOUS-SOLUTIONS
KW - ACID
KW - PHARMACEUTICALS
KW - OXYGEN
KW - WASTE-WATER
KW - DRUGS
KW - LASER FLASH
KW - PHOTOCHEMISTRY
KW - DISSOLVED ORGANIC-MATTER
KW - PHOTOLYSIS
KW - Water Pollutants, Chemical
KW - Humic Substances/analysis
KW - Photolysis
KW - Sunlight
UR - http://www.scopus.com/inward/record.url?scp=85086758024&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2020.140298
DO - 10.1016/j.scitotenv.2020.140298
M3 - Article
C2 - 32806347
AN - SCOPUS:85086758024
VL - 738
JO - Science of the Total Environment
JF - Science of the Total Environment
SN - 0048-9697
M1 - 140298
ER -
ID: 24567960