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Kinetics of ethyl paraben degradation by simulated solar radiation in the presence of N-doped TiO2 catalysts.
Water Res. 2015 Sep 15; 81:157-66.WR

Abstract

Ethyl paraben (EP), an emerging micro-pollutant representative of the parabens family, has been subject to photocatalytic degradation under simulated solar radiation at a photon flux of 1.3·10(-4) E/(m(2) s). Six nitrogen-doped titania catalysts synthesized by annealing a sol-gel derived TiO2 powder under ammonia flow and their un-doped counterparts, calcined in air at different temperatures in the range 450-800 °C, were compared under solar and visible light and the most active one (N-doped TiO2 calcined at 600 °C) was used for further tests. Experiments were performed at EP concentrations between 150 and 900 μg/L, catalyst loadings between 100 and 1000 mg/L, pH between 3 and 9, different matrices (ultrapure water, water spiked with humic acids or bicarbonates, drinking water and secondary treated wastewater) and hydrogen peroxide between 10 and 100 mg/L. For EP concentrations up to 300 μg/L, the degradation rate can be approached by first order kinetics but then shifts to lower order as the concentration increases. The rate increases linearly with catalyst loading up to 750 mg/L and hydrogen peroxide up to 100 mg/L. Near-neutral (pH = 6.5-7.5) and alkaline conditions (pH = 9) do not affect degradation, which is reduced at acidic pH. The presence of humic acids at 10-20 mg/L impedes degradation due to the competition with EP for the oxidizing species and this is more pronounced in actual wastewater matrices. UPLC-ESI-HRMS and HPLC-DAD were employed to follow EP concentration changes, as well as identify and quantify transformation by-products during the early stages of the reaction. Five such products were successfully detected and, based on their concentration-time profiles, a reaction network for the degradation of EP is proposed. Hydroxyl radical reactions appear to prevail during the initial steps as evidenced by the rapid formation of hydroxylated and dealkylated intermediates.

Authors+Show Affiliations

Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece.Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece.Department of Environmental & Natural Resources Management, University of Patras, 2 Seferi St., GR-30100 Agrinio, Greece.Department of Environmental & Natural Resources Management, University of Patras, 2 Seferi St., GR-30100 Agrinio, Greece.Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece.Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece. Electronic address: mantzavinos@chemeng.upatras.gr.

Pub Type(s)

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

Language

eng

PubMed ID

26057263

Citation

Petala, Athanasia, et al. "Kinetics of Ethyl Paraben Degradation By Simulated Solar Radiation in the Presence of N-doped TiO2 Catalysts." Water Research, vol. 81, 2015, pp. 157-66.
Petala A, Frontistis Z, Antonopoulou M, et al. Kinetics of ethyl paraben degradation by simulated solar radiation in the presence of N-doped TiO2 catalysts. Water Res. 2015;81:157-66.
Petala, A., Frontistis, Z., Antonopoulou, M., Konstantinou, I., Kondarides, D. I., & Mantzavinos, D. (2015). Kinetics of ethyl paraben degradation by simulated solar radiation in the presence of N-doped TiO2 catalysts. Water Research, 81, 157-66. https://doi.org/10.1016/j.watres.2015.05.056
Petala A, et al. Kinetics of Ethyl Paraben Degradation By Simulated Solar Radiation in the Presence of N-doped TiO2 Catalysts. Water Res. 2015 Sep 15;81:157-66. PubMed PMID: 26057263.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Kinetics of ethyl paraben degradation by simulated solar radiation in the presence of N-doped TiO2 catalysts. AU - Petala,Athanasia, AU - Frontistis,Zacharias, AU - Antonopoulou,Maria, AU - Konstantinou,Ioannis, AU - Kondarides,Dimitris I, AU - Mantzavinos,Dionissios, Y1 - 2015/05/29/ PY - 2015/03/23/received PY - 2015/05/20/revised PY - 2015/05/28/accepted PY - 2015/6/10/entrez PY - 2015/6/10/pubmed PY - 2016/3/30/medline KW - Parabens KW - Pathways KW - Photocatalysts KW - Process variables KW - Visible light KW - Water SP - 157 EP - 66 JF - Water research JO - Water Res. VL - 81 N2 - Ethyl paraben (EP), an emerging micro-pollutant representative of the parabens family, has been subject to photocatalytic degradation under simulated solar radiation at a photon flux of 1.3·10(-4) E/(m(2) s). Six nitrogen-doped titania catalysts synthesized by annealing a sol-gel derived TiO2 powder under ammonia flow and their un-doped counterparts, calcined in air at different temperatures in the range 450-800 °C, were compared under solar and visible light and the most active one (N-doped TiO2 calcined at 600 °C) was used for further tests. Experiments were performed at EP concentrations between 150 and 900 μg/L, catalyst loadings between 100 and 1000 mg/L, pH between 3 and 9, different matrices (ultrapure water, water spiked with humic acids or bicarbonates, drinking water and secondary treated wastewater) and hydrogen peroxide between 10 and 100 mg/L. For EP concentrations up to 300 μg/L, the degradation rate can be approached by first order kinetics but then shifts to lower order as the concentration increases. The rate increases linearly with catalyst loading up to 750 mg/L and hydrogen peroxide up to 100 mg/L. Near-neutral (pH = 6.5-7.5) and alkaline conditions (pH = 9) do not affect degradation, which is reduced at acidic pH. The presence of humic acids at 10-20 mg/L impedes degradation due to the competition with EP for the oxidizing species and this is more pronounced in actual wastewater matrices. UPLC-ESI-HRMS and HPLC-DAD were employed to follow EP concentration changes, as well as identify and quantify transformation by-products during the early stages of the reaction. Five such products were successfully detected and, based on their concentration-time profiles, a reaction network for the degradation of EP is proposed. Hydroxyl radical reactions appear to prevail during the initial steps as evidenced by the rapid formation of hydroxylated and dealkylated intermediates. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/26057263/Kinetics_of_ethyl_paraben_degradation_by_simulated_solar_radiation_in_the_presence_of_N_doped_TiO2_catalysts_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0043-1354(15)30040-3 DB - PRIME DP - Unbound Medicine ER -