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Photodegradation kinetics, products and mechanism of timolol under simulated sunlight.
J Hazard Mater. 2013 May 15; 252-253:220-6.JH

Abstract

The photodegradation of β-blocker timolol in fulvic acid (FA) solution was investigated under simulated sunlight. The triplet excited state of FA ((3)FA(*)) and singlet oxygen ((1)O2) were the main reactive species responsible for the degradation of timolol in the aerated FA solutions. Both dissolved oxygen and iodide ions (I(-)) are the efficient quenchers of (3)FA(*). The photodegradation was drastically accelerated after removing the dissolved oxygen. The presence of I(-) inhibited the photosensitized degradation of timolol in the deoxygenated FA solutions, whereas the role of I(-) in the reaction was concentration-dependent in the aerated solutions. The other halide ions such as chloride (Cl(-)) and bromide (Br(-)) exhibited less effect on the photodegradation of timolol in both aerated and deoxygenated solutions. By LC-DAD/ESI-MS/MS analysis, the photoproducts of timolol in both aerated and deoxygenated FA solutions were identified. Electron transfer interaction occurred between (3)FA(*) and amine moiety of timolol, leading to the cleavage of C-O bond in the side chain and oxidation of the hexatomic ring. These findings suggest the photosensitized degradation was a significant pathway for the elimination of timolol in natural waters.

Authors+Show Affiliations

School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China. ychen@hust.edu.cnNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23523913

Citation

Chen, Yong, et al. "Photodegradation Kinetics, Products and Mechanism of Timolol Under Simulated Sunlight." Journal of Hazardous Materials, vol. 252-253, 2013, pp. 220-6.
Chen Y, Liang Q, Zhou D, et al. Photodegradation kinetics, products and mechanism of timolol under simulated sunlight. J Hazard Mater. 2013;252-253:220-6.
Chen, Y., Liang, Q., Zhou, D., Wang, Z., Tao, T., & Zuo, Y. (2013). Photodegradation kinetics, products and mechanism of timolol under simulated sunlight. Journal of Hazardous Materials, 252-253, 220-6. https://doi.org/10.1016/j.jhazmat.2013.02.035
Chen Y, et al. Photodegradation Kinetics, Products and Mechanism of Timolol Under Simulated Sunlight. J Hazard Mater. 2013 May 15;252-253:220-6. PubMed PMID: 23523913.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photodegradation kinetics, products and mechanism of timolol under simulated sunlight. AU - Chen,Yong, AU - Liang,Qi, AU - Zhou,Danna, AU - Wang,Zongping, AU - Tao,Tao, AU - Zuo,Yuegang, Y1 - 2013/02/28/ PY - 2012/12/15/received PY - 2013/01/28/revised PY - 2013/02/15/accepted PY - 2013/3/26/entrez PY - 2013/3/26/pubmed PY - 2013/10/23/medline SP - 220 EP - 6 JF - Journal of hazardous materials JO - J Hazard Mater VL - 252-253 N2 - The photodegradation of β-blocker timolol in fulvic acid (FA) solution was investigated under simulated sunlight. The triplet excited state of FA ((3)FA(*)) and singlet oxygen ((1)O2) were the main reactive species responsible for the degradation of timolol in the aerated FA solutions. Both dissolved oxygen and iodide ions (I(-)) are the efficient quenchers of (3)FA(*). The photodegradation was drastically accelerated after removing the dissolved oxygen. The presence of I(-) inhibited the photosensitized degradation of timolol in the deoxygenated FA solutions, whereas the role of I(-) in the reaction was concentration-dependent in the aerated solutions. The other halide ions such as chloride (Cl(-)) and bromide (Br(-)) exhibited less effect on the photodegradation of timolol in both aerated and deoxygenated solutions. By LC-DAD/ESI-MS/MS analysis, the photoproducts of timolol in both aerated and deoxygenated FA solutions were identified. Electron transfer interaction occurred between (3)FA(*) and amine moiety of timolol, leading to the cleavage of C-O bond in the side chain and oxidation of the hexatomic ring. These findings suggest the photosensitized degradation was a significant pathway for the elimination of timolol in natural waters. SN - 1873-3336 UR - https://www.unboundmedicine.com/medline/citation/23523913/Photodegradation_kinetics_products_and_mechanism_of_timolol_under_simulated_sunlight_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0304-3894(13)00151-9 DB - PRIME DP - Unbound Medicine ER -