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Choo ZS, Hsieh MC, Lin HHH, Yang JS, Lin AYC. Reactive chlorine species in the enhanced degradation of UV stabilizers during the sunlight/free chlorine process. CHEMOSPHERE 2022; 309:136677. [PMID: 36191762 DOI: 10.1016/j.chemosphere.2022.136677] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 06/16/2023]
Abstract
Benzotriazole (BT) and 5-methyl-1H-benzotriazole (5-MeBT) are the most commonly used UV stabilizers and recalcitrant contaminants that are widely distributed in aquatic environments. The novelty of this study was to investigate the role of RCSs in the enhanced degradation of BT and 5-MeBT during the sunlight/free chlorine process. The results showed that sunlight/free chlorine could enhance the degradation of BT and 5-MeBT compared with that obtained with sunlight irradiation and chlorination alone, and this process was well described by pseudo-first-order kinetics. The degradation rate constants of BT and 5-MeBT during sunlight/free chlorine treatment at pH 7 were 0.094 ± 0.001 min-1 and 0.134 ± 0.002 min-1, respectively. The degradation rates further increased with increases in the chlorine dosage and under alkaline conditions (3.818 ± 0.243 min-1 for BT and 7.754 ± 0.716 min-1 for 5-MeBT at pH 9). The enhanced removal obtained during the sunlight/free chlorine process could be attributed to the generation of HO• and reactive chlorine species (RCSs), such as Cl• and ClO•. Under alkaline conditions, RCSs were the dominant reactive species, and their contribution increased from 21.2% to 98.7% with increases in the pH from 7 to 9; this phenomenon was due to changes in free chlorine and BT speciation. Radical scavenging tests further verified that BT was mainly decomposed by ClO•, and ClO• showed high reactivity toward deprotonated BT through second-order rate constant estimation. A byproduct analysis demonstrated that BT underwent hydroxylation and chlorine substitution, and a high yield of 1-chlorobenzotriazole (1-ClBT) formation was observed. Even though the sunlight/free chlorine process resulted in a low level of mineralization, no Microtox® toxicity was detected in the treated solutions. Briefly, the significant contribution of ClO• to BT removal under alkaline conditions implies that sunlight/free chlorine could be utilized in a broader range of treatment conditions.
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Affiliation(s)
- Zhen-Shuen Choo
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 106, Taiwan
| | - Ming-Chi Hsieh
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 106, Taiwan
| | - Hank Hui-Hsiang Lin
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 106, Taiwan
| | - Jheng-Sian Yang
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 106, Taiwan
| | - Angela Yu-Chen Lin
- Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Rd., Taipei, 106, Taiwan.
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Construction of Mg-doped ZnO/g-C3N4@ZIF-8 multi-component catalyst with superior catalytic performance for the degradation of illicit drug under visible light. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.129536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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de Souza LP, Graça CAL, Teixeira ACSC, Chiavone-Filho O. Degradation of 2,4,6-trichlorophenol in aqueous systems through the association of zero-valent-copper-mediated reduction and UVC/H 2O 2: effect of water matrix and toxicity assessment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:24057-24066. [PMID: 33420930 DOI: 10.1007/s11356-020-11885-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
The presence of toxic chlorinated compounds in drinking water, generated during the disinfection step in water treatment plants, is of great concern for public health. In the present study, the performance of the UVC/H2O2 process, preceded by zero-valent-copper reduction, was evaluated for degrading 2,4,6-trichlorophenol (TCP). With this aim, the oxidation performed alone or in combination with the pre-reductive step was evaluated regarding TCP concentration over time, removal rate, mineralization, and toxicity to Vibrio fischeri, as well as oxidant dosage and the effect of water matrix. The UV/H2O2 process achieved fast (kobs = 1.4 min-1) and complete TCP degradation, as well as important mineralization (40.4%), with best results obtained for initial H2O2 concentration of 0.056 mmol L-1. Coupling of reductive and oxidative processes intensified contaminant mineralization, due to the synergistic effect of copper ions leached in the reductive process, particularly Cu(I), providing an additional route of H2O2 activation for generating HO• radicals (photo-Fenton-like process). High toxicity removals and increased mineralization could be successfully accomplished by the combined processes even in tap water, which is a clear advantage for practical application.
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Affiliation(s)
- Larissa Pinheiro de Souza
- Research Group in Advanced Oxidation Processes (AdOx), Department of Chemical Engineering, University of São Paulo, São Paulo, Brazil.
| | - Cátia Alexandra Leça Graça
- Laboratory of Separation and Reaction Engineering and Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical Engineering, University of Porto, Porto, Portugal
| | - Antonio Carlos S C Teixeira
- Research Group in Advanced Oxidation Processes (AdOx), Department of Chemical Engineering, University of São Paulo, São Paulo, Brazil
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Chassaing FJ, Mahmudov R, Metcalfe CD, Yargeau V. Changes to levels of microcontaminants and biological responses in rainbow trout exposed to extracts from wastewater treated by catalytic ozonation. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124110. [PMID: 33049625 DOI: 10.1016/j.jhazmat.2020.124110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/17/2020] [Accepted: 09/20/2020] [Indexed: 06/11/2023]
Abstract
Two separate pilot-scale studies were performed at two wastewater treatment plants comparing conventional ozonation and catalytic ozonation with an alumina-based catalyst supplied by BASF. The results of the first pilot study showed that catalytic ozonation achieved the same degree of disinfection as conventional ozonation with 30% lower applied ozone dose and enhanced the removal of several contaminants of emerging concern (CECs). The second pilot study conducted over 6 months of operation with the same batch of catalyst showed sustained enhanced removal of CECs relative to ozonation alone. The removals of CECs by catalytic ozonation was particularly effective for compounds with low reaction rates with ozone, indicating reactions with hydroxyl radicals formed in the presence of the catalyst. Analysis of plasma vitellogenin and total glutathione in liver tissues of juvenile rainbow trout (Oncorhynchus mykiss) injected with wastewater extracts indicated that catalytic ozonation removed the estrogenic activity and modulated oxidative stress caused by exposure to the organic compounds in wastewater extracts. Analysis of other biomarker responses indicated that no transformation products were formed that can cause lipid damage in the liver or affect levels of a brain neurotransmitter (i.e. serotonin). Catalytic ozonation is a promising technology to increase the efficiency of ozone treatment of municipal wastewater and to meet increasingly more stringent regulations for effluent quality.
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Affiliation(s)
| | | | - Chris D Metcalfe
- School of the Environment, Trent University, Peterborough, ON, Canada
| | - Viviane Yargeau
- Department of Chemical Engineering, McGill University, Montreal, QC, Canada.
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Lai WWP, Chen KL, Lin AYC. Solar photodegradation of the UV filter 4-methylbenzylidene camphor in the presence of free chlorine. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 722:137860. [PMID: 32197163 DOI: 10.1016/j.scitotenv.2020.137860] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 02/24/2020] [Accepted: 03/10/2020] [Indexed: 06/10/2023]
Abstract
UV filters are essential ingredients in sunscreens and many personal care products. The coexposure of UV filters to solar photolysis and free chlorine (solar/free chlorine) is inevitable in outdoor swimming pools and many other aquatic matrices, and this study aims to investigate the degradation mechanism of one specific UV filter, 4-methylbenzylidene camphor (4MBC), under solar/free chlorine system. Under solar irradiation alone, 4MBC only undergoes isomerization from (E)- to (Z)-4MBC; however, in the solar/free chlorine system, 4MBC was significantly degraded, with a pseudo-first-order rate constant of 0.0137 s-1 (pH = 7). The effects of the initial free chlorine concentration, solution pH and water matrix (presence of dissolved organic matter, HCO3- and Cl-) were studied. The results revealed that reactive chlorine species (RCS) are the dominant species influencing 4MBC degradation via solar/free chlorine, while OH and O3 played minor roles. These species would likely react with the 4-methylstyrene moiety of 4MBC and subsequently lead to 4MBC degradation through hydroxylation, chlorine substitution, oxidation and demethylation. Nevertheless, the dramatic increase in acute toxicity (Microtox®) during solar/free chlorine degradation of 4MBC highlights the need to further explore the transformation byproducts as well as their associated risks to humans and the environment.
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Affiliation(s)
- Webber Wei-Po Lai
- Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan
| | - Kuen-Lin Chen
- Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan
| | - Angela Yu-Chen Lin
- Graduate Institute of Environmental Engineering, National Taiwan University, 71, Chou-Shan Rd., Taipei 106, Taiwan; International Graduate Program of Molecular Science and Technology, National Taiwan University (NTU-MST), Taipei 106, Taiwan.
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Xiao K, Liang H, Chen S, Yang B, Zhang J, Li J. Enhanced photoelectrocatalytic degradation of bisphenol A and simultaneous production of hydrogen peroxide in saline wastewater treatment. CHEMOSPHERE 2019; 222:141-148. [PMID: 30703653 DOI: 10.1016/j.chemosphere.2019.01.109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 01/14/2019] [Accepted: 01/20/2019] [Indexed: 06/09/2023]
Abstract
The degradation of organic pollutants in saline wastewater has been a challenge for environmental remediation. In this study, a two-chamber cell was structured to simultaneously degrade organic contaminants (bisphenol A, BPA) from saline wastewater and produce hydrogen peroxide (H2O2). In the anode chamber, a new solar-light-driven system was devised using chloride ions (Cl‾) as a medium and WO3 photoanode as a radical initiator. Under solar light irradiation, photogenerated holes yielded at the WO3 photoanode promoted the conversion of Cl‾ to reactive chlorine species, which could oxidize BPA more rapidly. The results indicated that the BPA removal can be significantly enhanced by increasing pH to 10.8 or increasing the Cl‾ concentration to 200 mM. At these conditions, 92% BPA was degraded into CO2 and H2O in 120 min. In the cathode chamber, a new dopamine modified carbon felt (CF-DPA) cathode was employed to produce H2O2, obtaining a high concentration of 5.4 mM under optimum conditions. The electrochemical analyses for CF-DPA revealed that dopamine modification promoted electron transfer and enhanced the two-electron oxygen reduction to increase H2O2 yields.
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Affiliation(s)
- Ke Xiao
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Huiyu Liang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Siyuan Chen
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Bo Yang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China; Shenzhen Key Laboratory of Environmental Chemistry and Ecological Remediation, Shenzhen University, Shenzhen 518060, China.
| | - Junmin Zhang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
| | - Juying Li
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China
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Kostanjevecki P, Petric I, Loncar J, Smital T, Ahel M, Terzic S. Biodegradation study of methadone by adapted activated sludge: Elimination kinetics, transformation products and ecotoxicological evaluation. CHEMOSPHERE 2019; 214:719-728. [PMID: 30293025 DOI: 10.1016/j.chemosphere.2018.09.153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 06/08/2023]
Abstract
The biotransformation study of difficult-to-degrade opioid analgesic methadone (MTHD) was performed by activated sludge culture adapted to high concentration of methadone (10 mg/L). The study included determination of elimination kinetics of the parent compound, taxonomic characterization of microbial culture, identification of biotransformation products (TPs) and assessment of ecotoxicological effects of biotransformation processes. The chemical analyses were performed by ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry, whereas the ecotoxicological assessment was made based on determinations of toxicity to freshwater algae. Changes of the adapted sludge culture during the experiment were followed using the 16S rRNA gene amplicon sequencing. Depending on the experimental conditions, the elimination efficiency of methadone (10 mg/L) varied from 9% to 93% with the corresponding half-lives from 11.4 days to 1.5 days. A significantly faster elimination (t1/2 from 1.5 days to 5.8 days) was achieved at cometabolic conditions, using glucose-containing media, as compared to the experiments with MTHD as a single organic carbon source (t1/2 = 11.4 days). Moreover, increased biotransformation rate following the additional supplementation of ammonia, revealed a possible importance of nitrogen availability for the transformation at cometabolic conditions. The elimination of parent compound was associated with the formation of 3 different TPs, two of which were identical to main human metabolites of MTHD, 2-Ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and 2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline (EMDP). EDDP represented over 90% of the total TP concentration at the end of experiment. The biodegradation of MTHD was associated with a pronounced drop in algal toxicity, confirming a rather positive ecotoxicological outcome of the achieved biotransformation processes.
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Affiliation(s)
- Petra Kostanjevecki
- Division of Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10000, Zagreb, Croatia
| | - Ines Petric
- Division of Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10000, Zagreb, Croatia
| | - Jovica Loncar
- Division of Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10000, Zagreb, Croatia
| | - Tvrtko Smital
- Division of Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10000, Zagreb, Croatia
| | - Marijan Ahel
- Division of Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10000, Zagreb, Croatia
| | - Senka Terzic
- Division of Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10000, Zagreb, Croatia.
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