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Photodegradation kinetics of p-tert-octylphenol, 4-tert-octylphenoxy-acetic acid and ibuprofen under simulated solar conditions in surface water.
Chemosphere. 2011 Oct; 85(5):790-6.C

Abstract

Direct and indirect (sensitized) photolysis of p-tert-octylphenol (OP), 4-octylphenoxy-acetic acid (OP1EC), and ibuprofen (IBU) were investigated in laboratory water and surface water under simulated and natural sunlight conditions. Photodegradation obeyed apparent-first order kinetics with rates increasing in the presence of NO₂⁻, NO₃⁻, and humic acid (HAC). The bimolecular rate constants, k″, were determined for the reactions of OP and OP1EC with hydroxyl radical (·OH) using photolyzed hydrogen peroxide (H₂O₂) as the hydroxyl radical (·OH) and IBU as the reference compound. The k″ values for OP and OP1EC were (average and standard deviation) (10.9 ± 0.5) × 10⁹ M⁻¹ s⁻¹ and (8.6 ± 0.5) × 10⁹ M⁻¹ s⁻¹, respectively. Direct photolysis of OP is small with a quantum yield of 0.015 in the range of 285-295 nm. Based on laboratory and average solar intensity data, the estimated half-life of OP in different Singapore surface waters was estimated to range from 0.6 to 2.5d. The steady state hydroxyl radical concentration ([·OH](ss)) was estimated using a kinetic model that considered dissolved organic carbon compounds (DOC), nitrate, and nitrite as ·OH sources, and DOC, CO₃²⁻ and HCO₃⁻ as scavengers. In surface waters containing DOC 2.3-6.5 mg L⁻¹, nitrate 0-3.2 mg L⁻¹, and nitrite 0-2.5 mg L⁻¹, the calculated [·OH](ss) ranged from 5.2 × 10⁻¹⁵ to 9.6 × 10⁻¹⁵ M. Half-lives calculations based on this model underestimated the measured half-life by a factor of approximately 4.2 to 1.1. DOC was predicted to be the most important sensitizer except in a sample that contained relatively high nitrate and nitrite. In the presence of NO₃⁻, photoreactions produced nitrated OP and IBU. A mechanism for OP photolysis in the presence of nitrate is proposed.

Authors+Show Affiliations

School of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou Industrial Park, Suzhou, Jiangsu 215123, PR China.No 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

21745677

Citation

Xu, Yonglan, et al. "Photodegradation Kinetics of P-tert-octylphenol, 4-tert-octylphenoxy-acetic Acid and Ibuprofen Under Simulated Solar Conditions in Surface Water." Chemosphere, vol. 85, no. 5, 2011, pp. 790-6.
Xu Y, Nguyen TV, Reinhard M, et al. Photodegradation kinetics of p-tert-octylphenol, 4-tert-octylphenoxy-acetic acid and ibuprofen under simulated solar conditions in surface water. Chemosphere. 2011;85(5):790-6.
Xu, Y., Nguyen, T. V., Reinhard, M., & Gin, K. Y. (2011). Photodegradation kinetics of p-tert-octylphenol, 4-tert-octylphenoxy-acetic acid and ibuprofen under simulated solar conditions in surface water. Chemosphere, 85(5), 790-6. https://doi.org/10.1016/j.chemosphere.2011.06.069
Xu Y, et al. Photodegradation Kinetics of P-tert-octylphenol, 4-tert-octylphenoxy-acetic Acid and Ibuprofen Under Simulated Solar Conditions in Surface Water. Chemosphere. 2011;85(5):790-6. PubMed PMID: 21745677.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photodegradation kinetics of p-tert-octylphenol, 4-tert-octylphenoxy-acetic acid and ibuprofen under simulated solar conditions in surface water. AU - Xu,Yonglan, AU - Nguyen,Tung Viet, AU - Reinhard,Martin, AU - Gin,Karina Yew-Hoong, Y1 - 2011/07/13/ PY - 2011/02/21/received PY - 2011/06/13/revised PY - 2011/06/16/accepted PY - 2011/7/13/entrez PY - 2011/7/13/pubmed PY - 2012/3/1/medline SP - 790 EP - 6 JF - Chemosphere JO - Chemosphere VL - 85 IS - 5 N2 - Direct and indirect (sensitized) photolysis of p-tert-octylphenol (OP), 4-octylphenoxy-acetic acid (OP1EC), and ibuprofen (IBU) were investigated in laboratory water and surface water under simulated and natural sunlight conditions. Photodegradation obeyed apparent-first order kinetics with rates increasing in the presence of NO₂⁻, NO₃⁻, and humic acid (HAC). The bimolecular rate constants, k″, were determined for the reactions of OP and OP1EC with hydroxyl radical (·OH) using photolyzed hydrogen peroxide (H₂O₂) as the hydroxyl radical (·OH) and IBU as the reference compound. The k″ values for OP and OP1EC were (average and standard deviation) (10.9 ± 0.5) × 10⁹ M⁻¹ s⁻¹ and (8.6 ± 0.5) × 10⁹ M⁻¹ s⁻¹, respectively. Direct photolysis of OP is small with a quantum yield of 0.015 in the range of 285-295 nm. Based on laboratory and average solar intensity data, the estimated half-life of OP in different Singapore surface waters was estimated to range from 0.6 to 2.5d. The steady state hydroxyl radical concentration ([·OH](ss)) was estimated using a kinetic model that considered dissolved organic carbon compounds (DOC), nitrate, and nitrite as ·OH sources, and DOC, CO₃²⁻ and HCO₃⁻ as scavengers. In surface waters containing DOC 2.3-6.5 mg L⁻¹, nitrate 0-3.2 mg L⁻¹, and nitrite 0-2.5 mg L⁻¹, the calculated [·OH](ss) ranged from 5.2 × 10⁻¹⁵ to 9.6 × 10⁻¹⁵ M. Half-lives calculations based on this model underestimated the measured half-life by a factor of approximately 4.2 to 1.1. DOC was predicted to be the most important sensitizer except in a sample that contained relatively high nitrate and nitrite. In the presence of NO₃⁻, photoreactions produced nitrated OP and IBU. A mechanism for OP photolysis in the presence of nitrate is proposed. SN - 1879-1298 UR - https://www.unboundmedicine.com/medline/citation/21745677/Photodegradation_kinetics_of_p_tert_octylphenol_4_tert_octylphenoxy_acetic_acid_and_ibuprofen_under_simulated_solar_conditions_in_surface_water_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0045-6535(11)00726-0 DB - PRIME DP - Unbound Medicine ER -