Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism
Abstract
Understanding the degradation behavior of azo dyes in photocatalytic wastewater treatment is of fundamental and practical importance for their application in textile-processing and other coloration industries. In this study, quantum chemistry, as density functional theory, was used to elucidate different degradation pathways of azo pyridone dyes in a hydroxyl radical (HO•) initiated photocatalytic system. A series of substituted azo pyridone dyes were synthesized by changing the substituent group in the para position of the benzene moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The effect of dye molecular structure on the photocatalytic degradation reaction mechanism was analyzed and quantification of substituent effects on the thermodynamic and kinetics parameters was performed. Potential energy surface analysis revealed the most susceptible reaction site for the HO• attack. The calculated reaction barriers are found to be strongly affected by the... nature of substituent group with a good correlation using Hammett σp constants and experimentally determined reaction rates. The stability of pre-reaction complexes and transition state complexes were analyzed applying the distortion-interaction model. The increased stability of the transition state complexes with the distancing from the substituent group has been established.
Keywords:
Quantum chemical calculation / Density functional theory / Azo dye / Reaction mechanism / Photocatalytic degradation / Hydroxyl radical / Hammett equation / Substituent effectSource:
Journal of Environmental Sciences, 2020, 98, 14-21Publisher:
- Elsevier
Funding / projects:
- Slovenian Research Agency (research core funding No. P2-0152)
- Ministry of Science, Technological Development and Innovation of the Republic of Serbia, institutional funding - 200026 (University of Belgrade, Institute of Chemistry, Technology and Metallurgy - IChTM) (RS-MESTD-inst-2020-200026)
DOI: 10.1016/j.jes.2020.05.022
ISSN: 1001-0742
WoS: 000582127500002
Scopus: 2-s2.0-85086140433
Collections
Institution/Community
IHTMTY - JOUR AU - Dostanić, Jasmina AU - Huš, M. AU - Lončarević, Davor PY - 2020 UR - https://cer.ihtm.bg.ac.rs/handle/123456789/3600 AB - Understanding the degradation behavior of azo dyes in photocatalytic wastewater treatment is of fundamental and practical importance for their application in textile-processing and other coloration industries. In this study, quantum chemistry, as density functional theory, was used to elucidate different degradation pathways of azo pyridone dyes in a hydroxyl radical (HO•) initiated photocatalytic system. A series of substituted azo pyridone dyes were synthesized by changing the substituent group in the para position of the benzene moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The effect of dye molecular structure on the photocatalytic degradation reaction mechanism was analyzed and quantification of substituent effects on the thermodynamic and kinetics parameters was performed. Potential energy surface analysis revealed the most susceptible reaction site for the HO• attack. The calculated reaction barriers are found to be strongly affected by the nature of substituent group with a good correlation using Hammett σp constants and experimentally determined reaction rates. The stability of pre-reaction complexes and transition state complexes were analyzed applying the distortion-interaction model. The increased stability of the transition state complexes with the distancing from the substituent group has been established. PB - Elsevier T2 - Journal of Environmental Sciences T1 - Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism VL - 98 SP - 14 EP - 21 DO - 10.1016/j.jes.2020.05.022 ER -
@article{ author = "Dostanić, Jasmina and Huš, M. and Lončarević, Davor", year = "2020", abstract = "Understanding the degradation behavior of azo dyes in photocatalytic wastewater treatment is of fundamental and practical importance for their application in textile-processing and other coloration industries. In this study, quantum chemistry, as density functional theory, was used to elucidate different degradation pathways of azo pyridone dyes in a hydroxyl radical (HO•) initiated photocatalytic system. A series of substituted azo pyridone dyes were synthesized by changing the substituent group in the para position of the benzene moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The effect of dye molecular structure on the photocatalytic degradation reaction mechanism was analyzed and quantification of substituent effects on the thermodynamic and kinetics parameters was performed. Potential energy surface analysis revealed the most susceptible reaction site for the HO• attack. The calculated reaction barriers are found to be strongly affected by the nature of substituent group with a good correlation using Hammett σp constants and experimentally determined reaction rates. The stability of pre-reaction complexes and transition state complexes were analyzed applying the distortion-interaction model. The increased stability of the transition state complexes with the distancing from the substituent group has been established.", publisher = "Elsevier", journal = "Journal of Environmental Sciences", title = "Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism", volume = "98", pages = "14-21", doi = "10.1016/j.jes.2020.05.022" }
Dostanić, J., Huš, M.,& Lončarević, D.. (2020). Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism. in Journal of Environmental Sciences Elsevier., 98, 14-21. https://doi.org/10.1016/j.jes.2020.05.022
Dostanić J, Huš M, Lončarević D. Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism. in Journal of Environmental Sciences. 2020;98:14-21. doi:10.1016/j.jes.2020.05.022 .
Dostanić, Jasmina, Huš, M., Lončarević, Davor, "Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism" in Journal of Environmental Sciences, 98 (2020):14-21, https://doi.org/10.1016/j.jes.2020.05.022 . .