1
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Lin HHH, Lin AYC. Peracetic acid as an alternative disinfectant for micropollutants degradation and disinfection byproducts control in outdoor swimming pools. JOURNAL OF HAZARDOUS MATERIALS 2024; 464:132988. [PMID: 37979421 DOI: 10.1016/j.jhazmat.2023.132988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/27/2023] [Accepted: 11/09/2023] [Indexed: 11/20/2023]
Abstract
Peracetic acid (PAA) has garnered significant interest as a novel alternative to chlorine-based disinfectants for water treatment due to its broad-spectrum antimicrobial activity and its ability of reactive species generation when exposed to UV light. However, limited studies have investigated micropollutant degradation in the presence of PAA under solar irradiation. This is the first study to comprehensively investigate the photodegradation of caffeine (CAF) and 4-methylbenzylidene camphor (4-MBC) and the removal of disinfection byproducts (DBPs) in the presence of PAA under simulated solar light. The study revealed that the photodegradation of CAF and 4-MBC was significantly enhanced in the presence of PAA, following pseudo-first-order kinetics (R2 > 0.98) with reaction rates (kobs) of 0.220 and 0.111 h-1, respectively. In addition, substantial reduction of 21 DBPs, including trihalomethanes, haloacetic acids and haloacetonitriles, and no DBPs formation were observed in the presence of PAA and simulated solar irradiation. The proportion of coexisting H2O2 in the PAA solution considerably influenced target compounds degradation. CAF and 4-MBC were degraded faster under acidic conditions than under alkaline conditions. Hydroxyl radicals (·OH) dominated the degradation of CAF at different pH values, while direct photolysis and other reactive species played a major role in the degradation of 4-MBC.
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Affiliation(s)
- Hank Hui-Hsiang Lin
- 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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2
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Li P, Lu Z, Zou S, Yang L. Marine oil spill photodegradation: Laboratory simulation, affecting factors analysis and kinetic model development. MARINE POLLUTION BULLETIN 2023; 197:115729. [PMID: 37913562 DOI: 10.1016/j.marpolbul.2023.115729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 10/23/2023] [Accepted: 10/26/2023] [Indexed: 11/03/2023]
Abstract
Photodegradation significantly influences marine oil spill behavior, yet its role remains underrepresented in current models, impairing predictive accuracy. Addressing this, our study rigorously examined oil properties and environmental determinants affecting marine oil spill photodegradation through laboratory simulations. We identified and quantified key factors and their interactions, noting particularly the positive influence of asphaltene and negative implications of oil density. We also discerned a negative correlation between n-alkane degradation and carbon numbers. Our findings underscored the pivotal roles of temperature and irradiance in photodegradation. All tested oils adhered to first-order kinetics, with rate constants ranging from 0.0348 to 0.0645 day-1. Finally, we introduced a novel model incorporating temperature, irradiance and their interactions, ensuring reasonable simulations for marine oil spill photodegradation, fortifying marine oil spill management strategies.
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Affiliation(s)
- Pu Li
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhenhua Lu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Shichun Zou
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Lihua Yang
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Sciences, Sun Yat-sen University, Guangzhou 510275, China.
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3
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Liao Z, Lu J, Xie K, Wang Y, Yuan Y. Prediction of Photochemical Properties of Dissolved Organic Matter Using Machine Learning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:17971-17980. [PMID: 37029743 DOI: 10.1021/acs.est.2c07545] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Apparent quantum yields (Φ) of photochemically produced reactive intermediates (PPRIs) formed by dissolved organic matter (DOM) are vital to element cycles and contaminant fates in surface water. Simultaneous determination of ΦPPRI values from numerous water samples through existing experimental methods is time consuming and ineffective. Herein, machine learning models were developed with a systematic data set including 1329 data points to predict the values of three ΦPPRIs (Φ3DOM*, Φ1O2, and Φ·OH) based on DOM spectral parameters, experimental conditions, and calculation parameters. The best predictive performances for Φ3DOM*, Φ1O2, and Φ·OH were achieved using the CatBoost model, which outperformed the traditional linear regression models. The significances of the wavelength range and spectral parameters on the three ΦPPRI predictions were revealed, suggesting that DOM with lower molecular weight, lower aromatic content, and a more autochthonous portion possessed higher ΦPPRIs. Chain models were constructed by adding the predicted Φ3DOM* as a new feature into the Φ1O2 and Φ·OH models, which consequently improved the predictive performance of Φ1O2 but worsened the Φ·OH prediction likely due to the complex formation pathways of ·OH. Overall, this study offered robust ΦPPRI prediction across interlaboratory differences and provided new insights into the relationship between PPRIs formation and DOM properties.
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Affiliation(s)
- Zhiyang Liao
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Jinrong Lu
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Kunting Xie
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Yi Wang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
| | - Yong Yuan
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China
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4
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Peng J, Pan Y, Zhou Y, Kong Q, Lei Y, Lei X, Cheng S, Zhang X, Yang X. Triplet Photochemistry of Effluent Organic Matter in Degradation of Extracellular Antibiotic Resistance Genes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7230-7239. [PMID: 37114949 DOI: 10.1021/acs.est.2c08036] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Wastewater effluent is a major source of extracellular antibiotic resistance genes (eArGs) in the aquatic environment, a threat to human health and biosecurity. However, little is known about the extent to which organic matter in the wastewater effluent (EfOM) might contribute to photosensitized oxidation of eArGs. Triplet states of EfOM were found to dominate the degradation of eArGs (accounting for up to 85%). Photo-oxidation proceeded mainly via proton-coupled electron transfer reactions. They broke plasmid strands and damaged bases. O2•- was also involved, and it coupled with the reactions' intermediate radicals of eArGs. The second-order reaction rates of blaTEM-1 and tet-A segments (209-216 bps) with the triplet state of 4-carboxybenzophenone were calculated to be (2.61-2.75) × 108 M-1 s-1. Besides as photosensitizers, the antioxidant moieties in EfOM also acted as quenchers to revert intermediate radicals back to their original forms, reducing the rate of photodegradation. However, the terrestrial origin natural organic matter was unable to photosensitize because it formed less triplets, especially high-energy triplets, so its inhibitory effects predominated. This study advances our understanding of the role of EfOM in the photo-oxidation of eArGs and the difference between EfOM and terrestrial-origin natural organic matter.
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Affiliation(s)
- Jianglin Peng
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yanheng Pan
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yangjian Zhou
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Qingqing Kong
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yu Lei
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Lei
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Shuangshuang Cheng
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xinran Zhang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
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5
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Remke SC, Houska J, von Gunten U, Canonica S. Impact of chlorination and ozonation of dissolved organic matter on its photo-induced production of long-lived photooxidants and excited triplet states. WATER RESEARCH 2023; 239:119921. [PMID: 37230030 DOI: 10.1016/j.watres.2023.119921] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 03/19/2023] [Accepted: 03/26/2023] [Indexed: 05/27/2023]
Abstract
Recent studies suggested that long-lived photooxidants (LLPO), which are reactive intermediates formed during irradiation of dissolved organic matter (DOM), may consist of phenoxyl radicals derived from phenolic moieties of the DOM. Besides the well-studied excited triplet states of chromophoric DOM (3CDOM*), LLPO presumably are important photooxidants for the transformation of electron-rich contaminants in surface waters. The main objective of this study was to further test the potential role of phenoxyl radical as LLPO. Suwannee River fulvic acid (SRFA) as a model DOM was pre-oxidised using the phenol-reactive oxidants chlorine and ozone, followed by its characterization by the specific UV absorption at 254 nm (SUVA254), the ratio of absorbance at λ = 254 nm and λ = 365 nm (E2:E3), and the electron donating capacity (EDC). Subsequently, the photoreactivity of pre-oxidized SRFA was tested using 3,4-dimethoxyphenol (DMOP) as a LLPO probe compound at two initial concentrations ([DMOP]0 = 0.1 and 5.0 μM). Linear inter-correlations were observed for the relative changes in SUVA254, E2:E3, and EDC for increasing oxidant doses. Pseudo-first-order transformation rate constants normalized to the changing SRFA absorption rate (i.e., k0.1obs/rCDOMabsand k5.0obs/rCDOMabs, for 0.1 and 5.0 µM, respectively) exhibited the following distinct trends: The LLPO-dominated k0.1obs/rCDOMabsratio decreased with increasing oxidant dose and with decreasing SUVA254 and EDC, while the 3CDOM*-dominated k5.0obs/rCDOMabsratio positively correlated with E2:E3. Finally, it was concluded that precursors of 3CDOM* and LLPO are chemically modified differently by pre-oxidation of DOM, and LLPO precursors likely consist of phenolic moieties of DOM, suggesting phenoxyl radicals as LLPO.
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Affiliation(s)
- Stephanie C Remke
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Joanna Houska
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Urs von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
| | - Silvio Canonica
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, CH-8600 Dübendorf, Switzerland
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6
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Gan P, Lu Y, Li Y, Liu W, Chen L, Tong M, Liang J. Non-radical degradation of organic pharmaceuticals by g-C 3N 4 under visible light irradiation: The overlooked role of excitonic energy transfer. JOURNAL OF HAZARDOUS MATERIALS 2023; 445:130549. [PMID: 36495635 DOI: 10.1016/j.jhazmat.2022.130549] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/10/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
In this work, an excitonic energy transfer (EET) based non-radical mechanism was proposed for the degradation of organic pharmaceuticals by graphitic carbon nitride (g-C3N4) under visible light irradiation. Using diclofenac (DCF) as a model molecule, the competition between single electron transfer (SET) and EET was studied through modulating the exciton binding energy of g-C3N4. The different mechanisms of SET and EET for DCF degradation were predicted by DFT calculation, and further confirmed by their different degradation pathways. When EET played an important role, the rationality of some very popular radical scavengers, such as p-BQ, TEMPOL and furfuryl alcohol must be reconsidered. In addition, humic acid (HA) had a distinct effect on EET and SET. Specifically, HA enhanced the EET process through photosensitization, but suppressed SET through radical quenching effect. The effect of HA on DCF degradation depended on the contribution ratio of SET and ET.
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Affiliation(s)
- Pengfei Gan
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China
| | - Yi Lu
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China
| | - Yunyi Li
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China
| | - Wen Liu
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Peking University, Beijing 100871, PR China
| | - Long Chen
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Peking University, Beijing 100871, PR China
| | - Meiping Tong
- The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China
| | - Jialiang Liang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China.
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7
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Han K, Liu Y, Hu J, Jia J, Sun S. Effect of live and inactivated Chlamydomonas reinhardtii on the removal of tetracycline in aquatic environments. CHEMOSPHERE 2022; 309:136666. [PMID: 36220431 DOI: 10.1016/j.chemosphere.2022.136666] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/21/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
With the development of medical drugs, the widely used tetracycline has brought many adverse effects on the ecosystem and human health. Tetracycline pollution of water environment is becoming more and more serious, and has become an emerging environmental problem. As single celled organisms, microalgae are not only model organisms for risk assessment of aquatic ecosystems, but also can efficiently purify sewage. Microalgae-mediated pollutant remediation has attracted more and more attention from researchers. In this paper, Chlamydomonas reinhardtii (C. reinhardtii) was used to remove tetracycline in aqueous solution, and the removal efficiency and mechanism of microalgae on tetracycline were studied. The results showed that the removal rates of tetracycline by active and inactivated microalgae at a density of 5 × 106 cells·mL-1 were 81.9% and 89.8%, respectively. C. reinhardtii removed tetracycline through biosorption and nonmetabolic processes. Microalgal cell supernatant and hydroxyl radicals could significantly promote the removal of tetracycline. The positively charged tetracycline was electrostatically adsorbed on the microalgae surface and extracellular polymeric substances. Microalgae biomass can promote the production of ROS and enhance the ability of microalgae to remove tetracycline.
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Affiliation(s)
- Kai Han
- College of Resources and Environment, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Yanjun Liu
- College of Resources and Environment, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Jianan Hu
- College of Resources and Environment, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Junjie Jia
- College of Resources and Environment, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Shujuan Sun
- College of Resources and Environment, Shandong Agricultural University, Taian, Shandong, 271018, China.
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8
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Zhang H, Zheng Y, Wang XC, Zhang Q, Dzakpasu M. Photochemical behavior of constructed wetlands-derived dissolved organic matter and its effects on Bisphenol A photodegradation in secondary treated wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 845:157300. [PMID: 35842169 DOI: 10.1016/j.scitotenv.2022.157300] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Free water surface flow (FWS) constructed wetlands (CWs) have been broadly applied for polishing secondary treated effluents. Dissolved organic matter derived from FWS CWs (WDOM) plays key roles in contaminants transformations. Conversely, photodegradation could shape the quantity and quality of WDOM, thereby affecting its roles in the photolysis of organic micropollutants (OMPs). Nevertheless, whether and how solar irradiation-induced photodegradation modify the properties of WDOM, and the effects of WDOM on the photodegradation of OMPs remain unclear. This study elucidates the photochemical behavior of two WDOM isolated from field-scale FWS CWs for effluent polishing under simulated sunlight irradiation using spectroscopic tools and high-resolution mass spectra. Furthermore, the roles of WDOM in the photodegradation of Bisphenol A (BPA), as a representative endocrine-disrupting compound (EDC), were comprehensively investigated. Solar irradiation was demonstrated to lower the molecular weight and aromaticity of WDOM, as well as weaken its light absorption. Ultrahigh-resolution mass spectra further confirmed that aromatic and unsaturated structures were susceptible to solar irradiation-induced photodegradation reactions. Subsequently, less aromatic and more saturated structures eventually formed under sunlight irradiation, consistent with the result from spectroscopic characterization. The reactive species produced from WDOM significantly enhanced the photodegradation of BPA with the kobs noticeably increasing 4-fold compared with the kobs for direct photolysis. Additionally, 3WDOM* was identified as the dominant reactive species leading to the photolysis of BPA in the presence of WDOM. These findings improve understanding of the phototransformation behavior of WDOM under sunlight irradiation and the roles that WDOM plays in the photochemical fate of coexisting OMPs in CWs treatment systems.
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Affiliation(s)
- Hengfeng Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Yucong Zheng
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Xiaochang C Wang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Qionghua Zhang
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Mawuli Dzakpasu
- Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China.
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Hu A, Li L, Huang Y, Fu QL, Wang D, Zhang W. Photochemical transformation mechanisms of dissolved organic matters (DOM) derived from different bio-stabilization sludge. ENVIRONMENT INTERNATIONAL 2022; 169:107534. [PMID: 36152361 DOI: 10.1016/j.envint.2022.107534] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/16/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
Bio-stabilization sludge contains numerous dissolved organic matter (DOM) that could enter aquatic environments by soil leaching after sludge land use, but a clear understanding of their photochemical behavior is still lacking. In this study, we systematically investigated the photoactivity and photochemical transformation of aerobic composting sludge-derived DOM (DOMACS) and anaerobic digestion sludge-derived DOM (DOMADS) by using multispectral analysis coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results indicated that DOMACS and DOMADS have a higher proportion of highly unsaturated and phenolic compounds (HuPh)with high DBEwa, but the different polyphenols (Polyph) abundance of them, causing the different photoactivity between them. DOMACS had much higher apparent quantum yields (AQY) for triplet states of dissolved natural organic matter (3DOM*) and hydroxyl radical (•OH) but slightly lower AQY for singlet oxygen (1O2) than DOMADS under simulated sunlight conditions. As the irradiation time increased, HuPh and Polyph (associated with humic-like substances) contained in DOMACS (DOMADS) decreased by 12.0% (14.1%) and 3.0% (0.2%), respectively, with concurrent decrease in average molecular weight and aromaticity moieties, resulting in more generation of aliphatic compounds. Furthermore, based on 27 types of photochemical transformation reactions, DOMACS containing higher fractions of O10-15 and N1-3Oy class preferred dealkyl group and carboxylic acid reactions, whereas DOMADS composed of more N4Oy and S2Oy fragments preferred oxygen addition and anmine reactions. Consequently, photochemical transformations reduced the Cd (II) ion activity in the presence of DOMACS (DOMADS). This study is believed to unveil the photochemical transformation of bio-stabilization sludge-derived DOM and its impact on pollutants' fate in the aquatic environment.
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Affiliation(s)
- Aibin Hu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China
| | - Liqing Li
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Yao Huang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China
| | - Qing-Long Fu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China
| | - Dongsheng Wang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Weijun Zhang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, Hubei, China; State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China.
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10
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Song N, Wu D, Xu H, Jiang H. Integrated evaluation of the reactive oxygen species (ROS) production characteristics in one large lake under alternating flood and drought conditions. WATER RESEARCH 2022; 225:119136. [PMID: 36155006 DOI: 10.1016/j.watres.2022.119136] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/16/2022] [Accepted: 09/18/2022] [Indexed: 06/16/2023]
Abstract
Reactive oxygen species (ROS) are omnipresent in natural aquatic environments, and play an important role in biogeochemical cycles. One of the dominant sources of ROS in surface waters was thought to be from dissolved organic matter (DOM) interacting with photochemical process. The properties of DOM were different between the flood and drought periods in lakes; yet, information on how these variations influence ROS photoproduction is unknown. Through a three-year study, the photochemical properties of DOM and the resultant ROS photoproduction between the flood and drought period were determined in the largest freshwater lake in China (Lake Poyang). Results found that quantum yield coefficients of excited triplets (3CDOM*), apparent quantum yields of singlet oxygen (1O2) and hydroxyl radicals (•OH) were holistically higher in the flood period than those in the drought period. The optical properties of DOM showed that DOM in the flood period featured an allochthonous input, accompanied by higher molecular size (E2/E3), aromatic content (SUVA254), humification degree (HIX), while DOM in the drought period was mainly internal input. Fourier transform ion cyclotron resonance mass spectrometry (FI-ICR MS) further revealed that some refractory components, such as lignin-like and carboxyl-rich alicyclic molecules (CRAM) presented higher abundance in the flood period, and played the positive impacts on ROS production. Orthogonal partial least squares (OPLS) were used to build novel multivariate predictive models for indicating the spatio-temporal ROS production. Also, the relatively higher steady-state concentrations of 3CDOM* and 1O2 in the flood period could significantly diminish the half-lives of acetochlor. Considering the photochemical activity of DOM varied considerably at different periods, this study provided a new method to predict ROS production and contributed to a new insight into stage-specific emerging contaminants removing in natural aquatic environments.
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Affiliation(s)
- Na Song
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
| | - Dinggui Wu
- Organic Geochemistry Unit, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China
| | - Huacheng Xu
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China
| | - Helong Jiang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China.
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11
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Wan D, Wang J, Chen T, Xiang W, Selvinsimpson S, Chen Y. Effect of disinfection on the photoreactivity of effluent organic matter and photodegradation of organic contaminants. WATER RESEARCH 2022; 219:118552. [PMID: 35550969 DOI: 10.1016/j.watres.2022.118552] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/28/2022] [Accepted: 05/03/2022] [Indexed: 06/15/2023]
Abstract
Chlorine, UV254, and ozone are three typical processes commonly used for wastewater disinfection, which could change the photoreactivity of dissolved organic matter (DOM) in effluents of wastewater treatment plants (WWTPs). The photoinduced reactive species (RS) from DOM, primarily including the excited triplet state of DOM (3DOM*), singlet oxygen (1O2), and hydroxyl radical (•OH), play important roles in the attenuation of contaminants. However, the effect of disinfection processes on the photosensitized degradation of contaminants is poorly understood. This paper presents the first evidence that 3DOM*, 1O2, and •OH interaction with three typical contaminants (diphenhydramine, cimetidine, and N,N-diethyl-m-toluamide (DEET)) was largely impacted by DOM after disinfection. The results of electron spin resonance (ESR) spectrometry and laser flash photolysis (LFP) experiments demonstrated that the chlorination increased the formation rate of 3DOM* and 1O2, while UV254 irradiation and ozonation decreased the formation rate of these RS. All these three disinfection processes promoted the photoproduction of •OH and increased the photodegradation rate constants (kobs) of DEET by 26-361%. The kobs of diphenhydramine, cimetidine, and DEET correlated positively with the formation rate of 3DOM*, 1O2, and •OH, respectively. The bimolecular reaction rate constant of 3DOM* with diphenhydramine increased by ∼41% after chlorination. These findings suggest that disinfection processes altered the photogeneration of RS from DOM, which significantly impacts the fate of trace pollutants in aquatic environments.
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Affiliation(s)
- Dong Wan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Jie Wang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Tong Chen
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Weiming Xiang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | | | - Yong Chen
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China.
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12
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Sardana A, Weaver L, Aziz TN. Effects of dissolved organic matter characteristics on the photosensitized degradation of pharmaceuticals in wastewater treatment wetlands. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:805-824. [PMID: 35481471 DOI: 10.1039/d1em00545f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Wastewater treatment wetlands are aquatic systems where diverse dissolved organic matter (DOM) compositions physically interact. Complex photochemical behaviors ensue, leading to uncertainties in the prediction of indirect photodegradation rates for organic contaminants. Here, we evaluate the photosensitization ability of whole water DOM samples from a treatment wetland and wastewater treatment plant (WWTP) in North Carolina to photodegrade target pharmaceuticals. Optical characterization using ultraviolet-visible and excitation-emission matrix spectroscopy shows that wetland DOM has higher aromaticity than WWTP DOM and that WWTP secondary treatment processes increase aromaticity, overall molecular weight, and humic character of wastewater DOM. Our application of a reversed-phase HPLC method to assess DOM polarity distinctly reveals that a subset of the wetland samples possesses an abundance of hydrophobic DOM moieties. Hydroxyl radicals (˙OH) mediate the majority (>50%) of the indirect photodegradation for amoxicillin (AMX), atenolol (ATL), and 17α-ethinylestradiol (EE2), while singlet oxygen (1O2) is presumed to be solely responsible for the photodegradation of cimetidine (CME). Our findings suggest that hydrophobic interactions and improved accessibility to photogenerated reactive intermediates lead to significant increases in photosensitization efficiencies and overall indirect photodegradation rates of AMX, ATL, and EE2 for the hydrophobic wetland samples. In contrast, CME photosensitization yields are unaffected by polarity and trend positively with optical indicators of sunlight-induced DOM photobleaching and humification, suggesting that wetland processing favors faster 1O2 photogeneration. These relationships highlight the uncertainties in photosensitization yields and effects of DOM optical properties and polarity on the photochemical fate of organic contaminants.
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Affiliation(s)
- Arpit Sardana
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 3250 Fitts-Woolard Hall, 915 Partners Way, Raleigh NC 27695, USA.
- Geosyntec Consultants Inc., 2501 Blue Ridge Road, Suite 430, Raleigh, NC, 27607, USA
| | - Leah Weaver
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 3250 Fitts-Woolard Hall, 915 Partners Way, Raleigh NC 27695, USA.
| | - Tarek N Aziz
- Department of Civil, Construction, and Environmental Engineering, North Carolina State University, 3250 Fitts-Woolard Hall, 915 Partners Way, Raleigh NC 27695, USA.
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13
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Wu D, Li M, Du L, Ren D, Wang J. Straw return in paddy field alters photodegradation of organic contaminants by changing the quantity rather than the quality of water-soluble soil organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 821:153371. [PMID: 35085639 DOI: 10.1016/j.scitotenv.2022.153371] [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: 12/06/2021] [Revised: 01/16/2022] [Accepted: 01/20/2022] [Indexed: 05/27/2023]
Abstract
Straw return, an important agricultural management practice, is worldwide adopted to enhance soil carbon sequestration and soil fertility. Although water-soluble soil organic matter (WSOM) in paddy field is known to affect the photodegradation of organic contaminants, how straw return regulates the photosensitization of WSOM by changing its properties remain unclear. Here, we determined the temporal variations in the content, chemical characteristics, and photosensitizing ability of WSOM after wheat straw return in a wheat-rice rotation system using optical spectroscopy and steady-state photodegradation tests. After straw return, the WSOM content first increased to a maximum and then gradually decreased to pre-return level at day 90. Nevertheless, the relative abundance of humic-like components in WSOM was not shifted by straw return, and protein-like component in WSOM just showed a slight decrease at day 45. All the WSOM samples inhibited sulfamethoxazole (SMX) photodegradation by light filtering, reactive species quenching and other mechanisms, while promoted diuron (DIU) degradation via reacting with •OH, 1O2 and excited triplet WSOM. The photodegradation of SMX and DIU was little affected by straw return changing WSOM composition and photochemical activity. However, straw return could decelerate SMX and DIU photodegradation by elevating WSOM content in a relatively short-term. This study emphasizes that straw return may reduce the photodegradation of organic contaminants by increasing WSOM concentration instead of altering WSOM chemical characteristics.
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Affiliation(s)
- Dongming Wu
- Institute of Environment and Plant Protection, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Min Li
- College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China
| | - Ling Du
- College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China
| | - Dong Ren
- College of Environmental Science and Engineering, China West Normal University, Nanchong 637009, China; Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637009, China.
| | - Junjian Wang
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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14
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Wan D, Kong Y, Wang X, Selvinsimpson S, Sharma VK, Zuo Y, Chen Y. Effect of permanganate oxidation on the photoreactivity of dissolved organic matter for photodegradation of typical pharmaceuticals. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 813:152647. [PMID: 34968593 DOI: 10.1016/j.scitotenv.2021.152647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/19/2021] [Accepted: 12/19/2021] [Indexed: 06/14/2023]
Abstract
Permanganate has been widely used in the remediation of contaminated water due to its relatively strong oxidation properties and ease of use. The ubiquitous dissolved organic matter (DOM) in natural waters causes a significant sink of permanganate in treatments, which further impacts the photoformation of reactive species and the removal of trace pollutants by DOM. Significantly, the effect of permanganate oxidation on the photoreactivity of DOM remains unknown. The present paper investigated for the first time the photophysical and photochemical properties variation of DOM from different sources after permanganate oxidation. Results showed that the permanganate oxidation caused a decrease in UV absorbance, fluorescence intensity, aromaticity, and molecular weight for all tested DOM samples, as well as photoformation rate of DOM triplet states (3DOM⁎), singlet oxygen (1O2), and hydroxyl radical (OH) under simulated sunlight. Quantum yield of 1O2 showed positively linear correlations with both triplet quantum yield coefficient (fTMP) and E2/E3 (ratio of absorbance at 254 and 365 nm) for all the DOM samples before and after permanganate oxidation. The quantum yield of OH exhibited no significant correlation with fTMP or E2/E3. Permanganate oxidation inhibited the DOM-photosensitized indirect photodegradation of pollutants that do not absorb sunlight (e.g., decreased by 15-29%). For the tested pollutants that undergo direct photolysis under sunlight, their photodegradation was promoted (e.g., increased by 1-19%) in the permanganate oxidized DOM solutions due to the decrease of light-screening effect by DOM. These findings suggest that permanganate oxidation affects the photoreactivity of DOM and the corresponding photochemical fate of organic pollutants in natural waters.
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Affiliation(s)
- Dong Wan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Yaqian Kong
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Xing Wang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | | | - Virender K Sharma
- Department of Environmental and Occupational Health, School of Public Health, Texas A&M University, College Station, TX 77843, United States
| | - Yuegang Zuo
- University of Massachusetts Dartmouth, 285 Old Westport Road, North Dartmouth, MA 02747-2300, United States
| | - Yong Chen
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China.
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15
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Wang HJ, Lin HHH, Hsieh MC, Lin AYC. Photoaged polystyrene microplastics serve as photosensitizers that enhance cimetidine photolysis in an aqueous environment. CHEMOSPHERE 2022; 290:133352. [PMID: 34922962 DOI: 10.1016/j.chemosphere.2021.133352] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/09/2021] [Accepted: 12/09/2021] [Indexed: 06/14/2023]
Abstract
Microplastics (MPs) have received much attention in recent years because of their continuous photoaging process in aquatic environments. However, little research has been conducted on the photochemistry of aged microplastics and the associated effects on coexisting pharmaceuticals. This study investigated the photodegradation of cimetidine via aged polystyrene microplastics (PS-MPs) with different aging times (0-7 d) under simulated sunlight irradiation (700 W/m2). PS-MPs with 5 d of aging time resulted in much faster cimetidine degradation (>99%) after 2 h of irradiation than pristine PS-MPs (<8%). The enhanced photodegradation of cimetidine by aged PS-MPs was related to the increase in chromophoric oxygenated groups (CO, C-O) followed by redshifted absorbance through the photoaging process, which induced the formation of the environmentally persistent free radicals (EPFRs) OH, 1O2 and 3PS*. However, only 1O2 and 3PS* contributed to enhanced cimetidine photodegradation, with 1O2 playing a more important role in our case. This work also demonstrated that other compounds that are susceptible to indirect photolysis, such as codeine and morphine, are likewise significantly degraded under irradiation in the presence of aged PS-MPs. Although previous studies have reported how MPs can increase the persistence of contaminants, this study demonstrates that MPs can serve as photosensitizers and alter the fate of coexisting pharmaceuticals in aquatic environments.
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Affiliation(s)
- Hui-Ju Wang
- 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
| | - Ming-Chi Hsieh
- 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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16
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Wasswa J, Driscoll CT, Zeng T. Contrasting Impacts of Photochemical and Microbial Processing on the Photoreactivity of Dissolved Organic Matter in an Adirondack Lake Watershed. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:1688-1701. [PMID: 35041388 PMCID: PMC8812123 DOI: 10.1021/acs.est.1c06047] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Photochemical and microbial processing are the prevailing mechanisms that shape the composition and reactivity of dissolved organic matter (DOM); however, prior research has not comparatively evaluated the impacts of these processes on the photoproduction of reactive intermediates (RIs) from freshly sourced terrestrial DOM. We performed controlled irradiation and incubation experiments with leaf and soil samples collected from an acid-impacted lake watershed in the Adirondack Mountain region of New York to examine the effects of DOM processing on the apparent quantum yields of RIs (Φapp,RI), including excited triplet states of DOM (3DOM*), singlet oxygen (1O2), and hydroxyl radicals (•OH). Photodegradation led to net reductions in Φapp,1O2, Φapp,3DOM*, and Φapp,•OH, whereas (photo-)biodegradation resulted in increases in Φapp,1O2 and Φapp,3DOM*. Photodegradation and (photo-)biodegradation also shifted the energy distribution of 3DOM* in different directions. Multivariate statistical analyses revealed the potential relevance of photo-biodegradation in driving changes in Φapp,1O2 and Φapp,3DOM* and prioritized five bulk DOM optical and redox properties that best explained the variations in Φapp,1O2 and Φapp,3DOM* along the watershed terrestrial-aquatic continuum. Our findings highlight the contrasting impacts of photochemical and microbial processes on the photoreactivity of freshly sourced terrestrial DOM and invite further studies to develop a more holistic understanding of their implications for aquatic photochemistry.
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17
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Liao Z, Wang Y, Xie K, Xie N, Cai X, Zhou L, Yuan Y. Photochemistry of dissolved organic matter in water from the Pearl river (China): Seasonal patterns and predictive modelling. WATER RESEARCH 2022; 208:117875. [PMID: 34837813 DOI: 10.1016/j.watres.2021.117875] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 11/12/2021] [Accepted: 11/14/2021] [Indexed: 06/13/2023]
Abstract
Photochemical properties of dissolved organic matter (DOM) vary widely in natural and engineered water systems due to the different dominant compositions. However, seasonal patterns of DOM photochemical properties in urban rivers remain unclear. In this study, two seasons (wet and dry) of water samples were collected from eleven sites throughout the Pearl River (China) to investigate the spatiotemporal variability of DOM optical and photochemical properties. The optical properties of DOM in the Pearl River were characterized by UV-vis and fluorescence spectroscopies, which showed the substantial decrease in absorption coefficient and fluorescence intensity and increase in absorbence ratio (E2/E3) and specific absorption coefficient (SUVA) from the wet to dry season. The photochemical properties in terms of the apparent quantum yields of 3DOM*, 1O2 and ·OH from DOM (Φ3DOM*, Φ1O2 and Φ·OH, DOM) under illumination also displayed a significant decrease from the wet to the dry season. Spearman's rank correlation analysis revealed the strongest relationships between Φ3DOM*, Φ1O2 and Φ·OH, DOM and the relative abundance of microbial humic-like component (C2%) derived from parallel factor analysis (PARAFAC). Partial least squares regression (PLSR) modelling exhibited an excellent prediction strength for steady-state concentrations of 1O2 ([1O2]ss) and ·OH ([·OH]ss) with adjusted R2 values of 0.85 and 0.91, respectively, by using DOC concentration ([DOC]), optical properties, nitrate and nitrite concentrations as the response variables. In addition, the model identified that the Fmax of humic-like component C4 (Fmax-C4) was the most effective predictor amongst the used response variables. This study provides an approach to describe and predict the seasonal patterns of DOM photochemical properties in urbanized rivers, offering a good understanding of the formation mechanism of reactive species from river DOM.
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Affiliation(s)
- Zhiyang Liao
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Yi Wang
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Kunting Xie
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Nangeng Xie
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Xixi Cai
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Lihua Zhou
- School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou, 510006, PR China
| | - Yong Yuan
- Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, PR China.
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18
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Tian Y, Feng L, Li R, Li J, Du Z, Zhang L, Liu Y. Inhibitory effects of antioxidant moieties in humic substances on phototransformation of chlortetracycline mediated by the algae extracellular organic matter. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 798:149001. [PMID: 34325136 DOI: 10.1016/j.scitotenv.2021.149001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/19/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
In algae rich waters, sunlight-driven transformation of antibiotics could be accelerated via sensitization by algae extracellular organic matter (EOM), and this photosensitization process will be affected by coexisting humic substances. In this study, we explored the effect and mechanism of humic substances on photodegradation of chlortetracycline (CTC) mediated by EOM. We found that humic substances exhibited a marked inhibitory effect on the EOM-mediated photodegradation of CTC. Given that humic substances exhibited little effects on the EOM-mediated formation of triplet state species, the quenching effect of humic substances on reactive species was excluded. The inhibitory effect of humic substances was mainly attributed to the back reduction of CTC oxidation intermediates by the antioxidant moieties in humic substances. The ozone oxidation treatment for humic substances was applied to destroy antioxidant moieties. After ozonation, the inhibitory effects of humic substances were greatly decreased, confirming the dominant role of antioxidant moieties in humic substances, which inhibited CTC photodegradation mediated by EOM via reducing oxidation intermediates of CTC. This back reduction was further verified to be exergonic via reactive Gibbs free energy, indicating the back reduction by humic substances of CTC oxidation intermediates could occur spontaneously. The present study will be helpful for predicting the fate and risk of CTC in algae rich water environments, and is of great significance for the study of phototransformation of other antibiotics.
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Affiliation(s)
- Yajun Tian
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing 100083, China; College of Environment, Zhejiang University of Technology, Chaowang Road 18, Hangzhou 310014, China
| | - Li Feng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing 100083, China
| | - Renna Li
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing 100083, China
| | - Jun Li
- College of Environment, Zhejiang University of Technology, Chaowang Road 18, Hangzhou 310014, China
| | - Ziwen Du
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing 100083, China
| | - Liqiu Zhang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing 100083, China.
| | - Yongze Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing 100083, China
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19
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Wang Y, Marques Dos Santos M, Ding X, Labanowski J, Gombert B, Snyder SA, Croué JP. Impact of EfOM in the elimination of PPCPs by UV/chlorine: Radical chemistry and toxicity bioassays. WATER RESEARCH 2021; 204:117634. [PMID: 34543976 DOI: 10.1016/j.watres.2021.117634] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/01/2021] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
The UV/chlorine process as a potential tertiary municipal wastewater treatment alternative for removing refractory PPCPs has been widely investigated. However, the role of effluent organic matter (EfOM) on the radical chemistry and toxicity alteration is unclear. The elimination of two model PPCPs, primidone (PRM) and caffeine (CAF), by the co-exposure of UV and free chlorine was investigated to elucidate the impact of EfOM. Experimental results indicated that both •OH and reactive chlorine species (RCS) were importantly involved in the decay of PRM at acidic condition, while ClO• played dominant role at alkaline pH. The decay of CAF was dominated by ClO• under all conditions. Chlorine dose, initial contaminant concentration, solution pH, and water matrix affect the process efficiency at varying degree resulting from their specific effect on the radical speciation in the system. Presence of EfOM isolate remarkably inhibited the decay of PRM and CAF by preferentially scavenging RCS and particularly ClO•. Good correlations (linear for PRM and exponential for CAF) between UV absorbance at 254 nm and the observed pseudo first-order rate constants (k'obs) for all EfOM solutions were obtained, demonstrating the importance of aromatic moieties in inhibiting the degradation of targeted contaminants by UV/chlorine process. Degradation of PRM/CAF in reconstituted effluent spiked with the major effluent constituents (i.e., EfOM isolates, Cl-, HCO3-, and NO3-) was comparable to the results obtained with the real WWTP effluent and fit well to the correlation between k'obs and UV absorbance at 254 nm, suggesting that EfOM isolates can be used to determine the efficiency of UV/chlorine process in real effluent. EfOM serves as the main precursor of adsorbable organic chlorine in the UV/chlorine treatment. Bioassays indicated that chlorine-containing compounds could induce oxidative stress, mitochondrial dysfunction, and increase the cell DNA damage. Among evaluated treatment conditions, the nature of EfOM, hydrophobic versus transphilic fraction, is likely the predominant factor affecting the cytotoxicity. Meanwhile the UV/chlorine treatment can significantly reduce the cytotoxicity of EfOM isolates. However, adding high level of selected contaminants (e.g., PRM and CAF) can inhibit this phenomenon due to the competition with reactive radicals.
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Affiliation(s)
- Yuru Wang
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China; Institut de Chimie des Milieux et des Matériaux IC2MP UMR 7285 CNRS, Université de Poitiers, France.
| | - Mauricius Marques Dos Santos
- Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #06-08, 637141, Singapore
| | - Xinxin Ding
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Jérôme Labanowski
- Institut de Chimie des Milieux et des Matériaux IC2MP UMR 7285 CNRS, Université de Poitiers, France
| | - Bertrand Gombert
- Institut de Chimie des Milieux et des Matériaux IC2MP UMR 7285 CNRS, Université de Poitiers, France
| | - Shane Allen Snyder
- Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, CleanTech One, #06-08, 637141, Singapore
| | - Jean-Philippe Croué
- Institut de Chimie des Milieux et des Matériaux IC2MP UMR 7285 CNRS, Université de Poitiers, France.
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20
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Mangalgiri K, Cheng Z, Cervantes S, Spencer S, Liu H. UV-based advanced oxidation of dissolved organic matter in reverse osmosis concentrate from a potable water reuse facility: A Parallel-Factor (PARAFAC) analysis approach. WATER RESEARCH 2021; 204:117585. [PMID: 34478993 DOI: 10.1016/j.watres.2021.117585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/07/2021] [Accepted: 08/18/2021] [Indexed: 06/13/2023]
Abstract
Disposal of reverse osmosis concentrate (ROC) from advanced water purification facilities is a challenge associated with the implementation of reverse osmosis-based treatment of municipal wastewater effluent for potable reuse. In particular, the dissolved organic matter (DOM) present in ROC diminishes the quality of the receiving water upon environmental disposal and affects the toxicity, fate, and transport of organic contaminants. This study investigates UV-based advanced oxidation processes (UV-AOPs) for treating DOM in ROC using a Parallel Factor Analysis (PARAFAC) approach. DOM composition and degradation were tested in UV-only and three UV-AOPs using hydrogen peroxide (H2O2), free chlorine (Cl2), and persulfate (S2O82-). The four-component PARAFAC model consisted of two terrestrial humic-like components (CUVH and CVisH), a wastewater/nutrient tracer component (CNuTr), and a protein-like (tyrosine-like) component (CPrTy). Based on the observed loss in the maximum fluorescence intensity of the components, DOM degradation was determined to be dependent on UV fluence, oxidant dose, and dilution factor of the ROC (i.e., bulk DOM concentration). CVisH was most the photolabile component in the UV-only system, followed by CNuTr, CPrTy, and CUVH, respectively. Furthermore, UV-H2O2 and UV-S2O82- displayed faster overall reaction kinetics compared to UV-Cl2. The degradation trends suggested that CNuTr and CPrTy consisted of chemical moieties that were susceptible to reactive oxygen species (HO•) but not reactive chlorine species; whereas, CVisH was sensitive to all reactive species generated in the three UV-AOPs. Compared to other components, CPrTy was recalcitrant in all treatment scenarios tested. Calculations using chemical probe-based analysis also confirmed these trends in the reactivity of DOM components. The outcomes of this study form a foundation for characterizing ROC reactivity in UV-AOP treatment technologies, to ultimately improve the sustainability of water reuse systems.
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Affiliation(s)
- Kiranmayi Mangalgiri
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, United States
| | - Zhiwen Cheng
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, United States; School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China
| | - Sheila Cervantes
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, United States
| | - Samantha Spencer
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, United States
| | - Haizhou Liu
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, United States; Program of Environmental Toxicology, University of California, Riverside, CA 92521, United States.
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21
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Yin H, Wang Y, Huang J. Photodegradation-induced biological degradation of treated wastewater effluent organic matter in receiving waters. WATER RESEARCH 2021; 204:117567. [PMID: 34464744 DOI: 10.1016/j.watres.2021.117567] [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: 06/15/2021] [Revised: 08/08/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Effluent organic matter (EfOM) from wastewater treatment plants (WWTP) constitutes an important source of dissolved organic matter in receiving waters. Photodegradation may alter the properties of WWTP EfOM, thereby impacting its biodegradability and microbial respiration. However, whether and how natural sunlight exposure of EfOM affects its biodegradability and microbial oxygen consumption in the receiving waters are unclear. To address these knowledge gaps, incubation experiments of biodegradation, photodegradation, and bio-photodegradation were conducted with the effluent samples from a tertiary WWTP in Heifei, China. The quantity and quality of the EfOM were examined during the incubations to interpret changes in its lability and composition. The results showed that photodegradation facilitated and accelerated the EfOM biodegradation. After natural sunlight exposure, the EfOM degradation rate was significantly enhanced from 0.004 d-1 to 0.065 d-1 measured by dissolved organic carbon (DOC). Correspondingly, the DOC concentration of EfOM was reduced by 64.2% (26.6% by photodegradation and 37.5% by bio-photodegradation), while the concentration was only reduced by 5.3% in the direct biodegradation. Sunlight exposure of EfOM resulted in lower molecular weight, less aromatic, lower humified, more bleached photoproducts. These substances could be readily metabolized by the native microbial community in the receiving water, stimulating microbial respiration. Correspondingly, the oxygen consumption rate of EfOM increased from almost 0.11 mg L-1 d-1 in the direct biodegradation to 2.17 mg L-1 d-1 in the bio-photodegradation. This study highlights that after EfOM is discharged to the receiving water, its post-processing by sunlight can enhance biodegradability. The existence of the coupled photochemical and biological process is suggested to be considered when determining EfOM fate and managing effluent discharge in receiving waters.
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Affiliation(s)
- Hailong Yin
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China
| | - Yue Wang
- Rays Computational Intelligence Laboratory, Beijing Inteliway Environmental Science & Technology, Ltd., Beijing 100191, China
| | - Jingshui Huang
- Chair of Hydrology and River Basin Management, Technical University of Munich, Arcisstrasse 21, 80333 Munich, Germany.
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22
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Yeung CS, Tse HY, Lau CY, Guan J, Huang J, Phillips DL, Leu SY. Insights into unexpected photoisomerization from photooxidation of tribromoacetic acid in aqueous environment using ultrafast spectroscopy. JOURNAL OF HAZARDOUS MATERIALS 2021; 418:126214. [PMID: 34102359 DOI: 10.1016/j.jhazmat.2021.126214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/12/2021] [Accepted: 05/21/2021] [Indexed: 06/12/2023]
Abstract
Haloacetic acids are carcinogenic disinfection by-products (DPBs) and their photo-decomposition pathways, especially for those containing bromine and iodine, are not fully understood. In this study, femtosecond transient absorption (fs-TA) spectroscopy experiments were introduced for the first time to investigate the photochemistry of tribromoacetic acid. The fs-TA experiments showed that a photoisomerization intermediate species HOOCCBr2-Br (iso-TBAA) was formed within several picoseconds after the excitation of TBAA. The absorption wavelength of the iso-TBAA was supported by time-dependent density calculations. With the Second-order Møller-Plesset perturbation theory, the structures and thermodynamics of the OH-insertion reactions of iso-TBAA were elucidated when water molecules were involved in the reaction complex. The calculations also revealed that the isomer species were able to react with water with its reaction dynamics dramatically catalyzed by the hydrogen bonding network. The proposed water catalyzed OH-insertion/HBr elimination mechanism predicted three major photoproducts, namely, HBr, CO and CO2, which was consistent with the photolysis experiments with firstly reported CO formation rate and mass conversion yield as 0.096 min-1 and 0.75 ± 0.1 respectively. The spectroscopic technique, numerical tool and disclosed mechanisms provided insights on photodecomposition and subsequent reactions of polyhalo-DPBs contain heavy atom(s) (e.g., Br, I) with water, aliphatic alcohols or other nucleophiles.
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Affiliation(s)
- Chi Shun Yeung
- Department of Civil & Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong
| | - Ho-Yin Tse
- Department of Civil & Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong
| | - Chun Yin Lau
- Department of Civil & Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong
| | - Jianyu Guan
- Department of Civil & Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong
| | - Jinqing Huang
- Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong.
| | - Shao-Yuan Leu
- Department of Civil & Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong.
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23
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Partanen SB, Apell JN, Lin J, McNeill K. Factors affecting the mixed-layer concentrations of singlet oxygen in sunlit lakes. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2021; 23:1130-1145. [PMID: 34231605 PMCID: PMC8372756 DOI: 10.1039/d1em00062d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 06/16/2021] [Indexed: 06/01/2023]
Abstract
The steady-state concentration of singlet oxygen within a lake ([1O2]SS) is an important parameter that can affect the environmental half-life of pollutants and environmental fate modelling. However, values of [1O2]SS are often determined for the near-surface of a lake, and these values typically do not represent the average over the epilimnia of lakes. In this work, the environmental and physical factors that have the largest impact on [1O2]SS within lake epilimnia were identified. It was found that the depth of the epilimnion has the largest impact on depth-averaged [1O2]SS, with a factor of 8.8 decrease in [1O2]SS when epilimnion depth increases from 2 m to 20 m. The next most important factors are the wavelength-dependent singlet oxygen quantum yield relationship and the latitude of the lake, causing variations in [1O2]SS by factors of 3.2 and 2.5 respectively, over ranges of representative values. For a set of representative parameters, the depth-averaged value of [1O2]SS within an average epilimnion depth of 9.0 m was found to be 5.8 × 10-16 M and the near-surface value of [1O2]SS was found to be 1.9 × 10-14 M. We recommend a range of 6 × 10-17 to 5 × 10-15 M as being more representative of [1O2]SS values within the epilimnia of lakes globally and potentially more useful for estimating pollutant lifetimes than those calculated using [1O2]SS values that correspond to near-surface, summer midday values. This work advances our understanding of [1O2]SS inter-lake variability in the environment, and provides estimates of [1O2]SS for practitioners and researchers to assess environmental half-lives of pollutants due to reaction with singlet oxygen.
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Affiliation(s)
- Sarah B. Partanen
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich8092 ZurichSwitzerland
| | - Jennifer N. Apell
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich8092 ZurichSwitzerland
- Department of Civil and Urban Engineering, New York University Tandon School of Engineering6 MetroTech CenterBrooklynNY 11201USA
| | - Jianming Lin
- Firmenich IncorporatedP.O. Box 5880PrincetonNew Jersey 08543USA
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich8092 ZurichSwitzerland
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24
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Visible-Light Enhanced Catalytic Wet Peroxide Oxidation of Natural Organic Matter in the Presence of Al/Fe-Pillared Clay. Catalysts 2021. [DOI: 10.3390/catal11050637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
An Al/Fe-pillared clay catalyst (Al/Fe-PILC) prepared from low cost technical-grade reagents has been investigated in the photocatalytic Wet Peroxide Oxidation (photo-CWPO) of dissolved Natural Organic Matter (NOM) under circumneutral pH. The successful pillaring of the layered clay material was confirmed by X-ray diffraction (XRD), N2 adsorption at −196 °C, cation exchange capacity (CEC) and simultaneous thermal analysis (TGA/DSC). High levels of mineralization of the dissolved organic carbon and color removal of a synthetic NOM surrogate solution were achieved even under natural lab’s lighting and ambient temperature and pressure, whereas the absence of radiation (in dark) was found to strongly affect the performance of the degradation. The photo-CWPO of NOM activated by the Al/Fe-PILC clay catalyst under visible light irradiation (LED lamp, 450 and 550 nm peaks) displayed a DOC mineralization of 72% and color removal of 73% in just 210 min of irradiation at neutral pH, whereas both responses decayed under ultraviolet lightning (λ: 365 nm) to 41% and 58%, respectively. This behavior is ascribed to formation of triplet states of natural organic matter (3NOM*) by absorption of visible light, which seems to synergistically improve the rate-determining step of the heterogeneous Fenton process, namely reduction of Fe3+ into Fe2+ on the surface of the clay catalyst. Interestingly, experiments performed at neutral and pH 3.0 showed very similar efficiencies under visible light irradiation; these findings may really facilitate the application of the photo-CWPO process to assist conventional drinking water treatment plants in the removal of NOM before the typical disinfection by chlorine to produce safer drinking water.
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25
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Wang Y, Fan L, Jones OAH, Roddick F. Quantification of seasonal photo-induced formation of reactive intermediates in a municipal sewage lagoon upon sunlight exposure. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:142733. [PMID: 33572041 DOI: 10.1016/j.scitotenv.2020.142733] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/14/2020] [Accepted: 09/26/2020] [Indexed: 06/12/2023]
Abstract
Photochemically produced reactive oxygen species in wastewater lagoons upon sunlight exposure are important in the attenuation of emerging contaminants (ECs). The production of reactive radicals in wastewater lagoons depends on both environmental factors and the composition of effluent organic matter (EfOM) in the wastewater. Knowing the steady state concentrations of these reactive species produced in a particular lagoon wastewater is critical to the prediction of the persistence and attenuation of ECs in that sunlit wastewater treatment lagoon. This study quantified the formation of four photochemically produced reactive intermediates (PPRIs): hydroxyl radical, carbonate radical, singlet oxygen, and triplet excited state EfOM in 11 samples collected from a municipal wastewater lagoon over a full year. The temporal distribution of these key PPRIs in the lagoon under investigation was determined in relation to sunlight irradiance, wastewater composition and temperature. Greater sunlight intensity led to greater PPRI production over the year. Increasing wastewater temperature from 12 to 25 °C led to greater production of singlet oxygen, a moderate decrease in hydroxyl radical and increase in triplet excited state EfOM, and minimal impact on carbonate radical production. The optical properties of the lagoon wastewater of Napierian absorption coefficient (A300) and E2:E3 ratio could be used as indicators of the formation of singlet oxygen (Pearson's r = 0.79) and triplet excited EfOM (Pearson's r = 0.76) produced upon solar irradiation. The concentration of carbonate radical formed was strongly correlated to the nitrate level in the wastewater (Pearson's r = 0.85). The findings could be used for modelling the seasonal sunlight-induced photolysis process of ECs during lagoon-based wastewater treatment, with a view to optimising the treatment process, predicting the efficacy of EC removal, and risk assessment of the treated water.
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Affiliation(s)
- Yufei Wang
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria 3000, Australia
| | - Linhua Fan
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria 3000, Australia
| | - Oliver A H Jones
- School of Science, RMIT University, Bundoora West Campus, PO Box 71, Bundoora, Victoria 3083, Australia
| | - Felicity Roddick
- School of Engineering, RMIT University, GPO Box 2476, Melbourne, Victoria 3000, Australia.
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26
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Zhang K, Sun P, Khan A, Zhang Y. Photochemistry of biochar during ageing process: Reactive oxygen species generation and benzoic acid degradation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:144630. [PMID: 33385810 DOI: 10.1016/j.scitotenv.2020.144630] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/02/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
In this study, the photogeneration of OH and 1O2 and the degradation mechanism of organic pollutants in biochar suspension under the simulated solar light irradiations were investigated. Biochar derived from rice husk with 550 °C of charring temperature (R550) was selected to degrade benzoic acid. It was found that 10 g/L of R550 could degrade 78.7% of benzoic acid within 360 min at pH 3, and the degradation efficiency was promoted to 95.2% as ultraviolet (UV) presented. By checking the production of p-hydroxybenzoic acid, UV accelerated the production of OH, which was confirmed by the enhanced degradation efficiency of 59.2% caused by the evaluated OH as UV appeared. The furfuryl alcohol loss in the R550 suspension under light irradiations testified to the production of 1O2, which contributed to 9.3% of benzoic acid degradation. Oxidization treatment using gradient concentrations of H2O2 was employed to enhance the ageing process of biochar. As the ageing processed, the biochar possessed a declined performance towards OH production from O2 activation and the radical degradation of organic pollutants. As a contrast, the evaluated content of 1O2 and enhanced non-radical degradation of organic pollutants was reached as UV presented. The further study indicated that phenolic hydroxyl groups on biochar facilitated the production of OH via the electron transfer, and quinone like structures (C=O) on biochar boosted the generation of 1O2 via the energy transfer. Moreover, upon eliminating the BA degradation, persistent free radicals were formed on biochar, which was enhanced owing to the presence of UV.
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Affiliation(s)
- Kaikai Zhang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Peng Sun
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China; Institute of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou 014010, PR China
| | - Aimal Khan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China
| | - Yanrong Zhang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, PR China.
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27
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Ossola R, Jönsson OM, Moor K, McNeill K. Singlet Oxygen Quantum Yields in Environmental Waters. Chem Rev 2021; 121:4100-4146. [PMID: 33683861 DOI: 10.1021/acs.chemrev.0c00781] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Singlet oxygen (1O2) is a reactive oxygen species produced in sunlit waters via energy transfer from the triplet states of natural sensitizers. There has been an increasing interest in measuring apparent 1O2 quantum yields (ΦΔ) of aquatic and atmospheric organic matter samples, driven in part by the fact that this parameter can be used for environmental fate modeling of organic contaminants and to advance our understanding of dissolved organic matter photophysics. However, the lack of reproducibility across research groups and publications remains a challenge that significantly limits the usability of literature data. In the first part of this review, we critically evaluate the experimental techniques that have been used to determine ΦΔ values of natural organic matter, we identify and quantify sources of errors that potentially explain the large variability in the literature, and we provide general experimental recommendations for future studies. In the second part, we provide a qualitative overview of known ΦΔ trends as a function of organic matter type, isolation and extraction procedures, bulk water chemistry parameters, molecular and spectroscopic organic matter features, chemical treatments, wavelength, season, and location. This review is supplemented with a comprehensive database of ΦΔ values of environmental samples.
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Affiliation(s)
- Rachele Ossola
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Oskar Martin Jönsson
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
| | - Kyle Moor
- Utah Water Research Laboratory, Department of Civil and Environmental Engineering, Utah State University, 84322 Logan, Utah, United States
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zürich, 8092 Zürich, Switzerland
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28
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Wu B, Arnold WA, Ma L. Photolysis of atrazine: Role of triplet dissolved organic matter and limitations of sensitizers and quenchers. WATER RESEARCH 2021; 190:116659. [PMID: 33279742 DOI: 10.1016/j.watres.2020.116659] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/13/2020] [Accepted: 11/18/2020] [Indexed: 06/12/2023]
Abstract
Atrazine, a widely used herbicide, is susceptible to photolysis. The role of triplet excited states of chromophoric dissolved organic matter (3CDOM*) in the photolysis of atrazine, however, is not well understood. The direct photolysis of atrazine under irradiation sources (natural sunlight/environmentally relevant simulated solar light) and its indirect photochemical reactivity with model triplet photosensitizers (benzophenone, 2-acetonaphthone, 3'-methoxy-acetophenone, 4-carboxybenzophenone, rose bengal, methylene blue, and anthraquinone-2-sulphonate) was investigated. The reactivity of the model sensitizers and DOM (Suwannee River natural organic matter, river/lake water, and wastewater effluent), were compared. The direct photolysis quantum yield was determined as 0.0196 mol Einstein-1 in a solar simulator and 0.00437 mol Einstein-1 under natural sunlight. Considerable photosensitization was induced by triplet state (n-π*) model sensitizers, while insignificant effects on atrazine loss were discerned in natural organic matter even when oxygen, a triplet quencher, was removed. The triplet sensitizers benzophenone and 2-acetylnaphthone reacted with L-histidine and 2-propanol that were intended to quench/ scavenge 1O2 and hydroxyl radical •OH, respectively, and benzophenone reacted with NaN3 as a 1O2 scavenger and furfuryl alcohol as a 1O2 trapping agent, indicating quenchers may have unanticipated effects when using model sensitizers. Atrazine loss via reaction with 3DOM* will be relevant only in selected conditions, and this work provides a more comprehensive view on the use of model photosensitizers to mimic triplet 3DOM*.
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Affiliation(s)
- Bin Wu
- School of Environmental Science and Engineering, Tongji University, Shanghai, China; Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Technology, Tongji University, Shanghai, China; Department of Civil, Environmental, and Geo- Engineering, University of Minnesota - Twin Cities, 500 Pillsbury Drive SE, Minneapolis, MN 55455, United States
| | - William A Arnold
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota - Twin Cities, 500 Pillsbury Drive SE, Minneapolis, MN 55455, United States
| | - Limin Ma
- School of Environmental Science and Engineering, Tongji University, Shanghai, China.
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29
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Wang YK, Ma XY, Zhang S, Tang L, Zhang H, Wang XC. Sunlight-induced changes in naturally stored reclaimed water: Dissolved organic matter, micropollutant, and ecotoxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 753:141768. [PMID: 32896733 DOI: 10.1016/j.scitotenv.2020.141768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 06/11/2023]
Abstract
Natural sunlight is a vital environmental element and plays a significant role in the ecological storage of reclaimed water (RW), but its impacts on RW quality are poorly understood. In this study, sunlight-induced changes in RW with a focus on dissolved organic matter (rDOM) and 52 residual micropollutants were investigated in the field during the summer and winter seasons. The results indicated that sunlight exposure led to the dissipation of chromophoric DOM (CDOM) in the summer (55% loss) and winter (19% loss) after 14 consecutive sunny days. During open storage of RW, CDOM absorption in UVC regions was preferentially removed in the summer, while during the winter there was preferential removal of CDOM in UVA regions. The results also showed higher fluorescent DOM (FDOM) removal in summer than in winter (49% and 28%, respectively). Results in both seasons indicated that humic acid-like compounds were the most photolabile fractions and were preferentially removed under sunlight exposure. Sunlight also induced attenuation of micropollutants in the summer and winter at reductions of 66% and 24% from the initial values, respectively. Significant attenuation (>75%) was only observed for endocrine-disrupting chemicals, pharmaceuticals, and sunscreens in the summer, but they accounted for 76% of the total concentrations. Vibrio fischeri toxicity tests demonstrated that sunlight constantly decreased the luminescent bacteria acute toxicity of RW, which was estimated to be caused mainly by the sunlight-induced changes of FDOM and CDOM, while the detected micropollutants could only explain 0.02%-2% of acute toxicity. These findings have important implications regarding our understanding of the ecological storage of reclaimed water and the contribution of management strategies.
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Affiliation(s)
- Yongkun K Wang
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, People's Republic of China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, People's Republic of China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Xiaoyan Y Ma
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, People's Republic of China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, People's Republic of China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Shiying Zhang
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, People's Republic of China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, People's Republic of China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Lei Tang
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, People's Republic of China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, People's Republic of China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Hengfeng Zhang
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, People's Republic of China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, People's Republic of China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China
| | - Xiaochang C Wang
- International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, People's Republic of China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, People's Republic of China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, People's Republic of China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, People's Republic of China.
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30
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Wan D, Kong Y, Selvinsimpson S, Luo F, Chen Y. Effect of UV 254 disinfection on the photoformation of reactive species from effluent organic matter of wastewater treatment plant. WATER RESEARCH 2020; 185:116301. [PMID: 32818737 DOI: 10.1016/j.watres.2020.116301] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/24/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
UV254 is one of the main disinfection methods used in wastewater treatment plants (WWTPs) for the inactivation of pathogens in the effluents before being discharged into the receiving waters. The effluent organic matters (EfOM) are well-known photosensitizers for the generation of reactive species, mainly including the triplet states of EfOM (3EfOM*), singlet oxygen (1O2) and hydroxyl radical (•OH), which contribute to the removal of trace pollutants in water. However, the effect of UV254 disinfection on the photoreactivity of EfOM remains unclear. Here we investigated the photophysical and photochemical properties variation of EfOM after UV254 disinfection, along with humic substances (HS) as comparison. The UV254 disinfection caused a decrease of aromaticity, fluorescence intensity and molecular weight for all samples, while a reduction formation of triplet state of these dissolved organic matters (3DOM*), 1O2, hydrogen peroxide (H2O2), and superoxide anions (O2•-) under simulated sunlight was observed. In contrast, the generation of •OH was increased after UV254 disinfection. The quantum yield of 1O2 was positively correlated with triplet quantum yield coefficient (fTMP) in all cases. However, the quantum yield of •OH exhibited positive and negative correlations with fTMP for EfOM and HS, respectively. The quantum yields showed positive correlations with E2/E3 (ratio of the absorbance at 254 to 365 nm) for untreated DOM samples, while for the first time we found the trends differ distinctly after UV254 disinfection. These findings indicate that UV254 disinfection in WWTPs significantly increases the potential of •OH photoproduction from effluents and the cost-effective solar irradiation after UV254 disinfection is expected to be a novel technique for further removal of pathogen and trace organic pollutants in wastewater effluents and receiving waters.
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Affiliation(s)
- Dong Wan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China
| | - Yaqian Kong
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China
| | | | - Fan Luo
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China
| | - Yong Chen
- School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, PR China; Advanced Technology Institute of Suzhou, Suzhou, 215123, PR China.
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31
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Modiri Gharehveran M, Hain E, Blaney L, Shah AD. Influence of dissolved organic matter on carbonyl sulfide and carbon disulfide formation from cysteine during sunlight photolysis. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1852-1864. [PMID: 32966465 DOI: 10.1039/d0em00219d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Carbonyl sulfide (COS) and carbon disulfide (CS2) are important atmospheric gases that are formed from organic sulfur precursors present in natural waters when exposed to sunlight. However, it remains unclear how specific water constituents, such as dissolved organic matter (DOM), affect COS and CS2 formation. To better understand the role of DOM, irradiation experiments were conducted in O2-free synthetic waters containing four different DOM isolates, acquired from freshwater to open ocean sources, and the sulfur-based amino acid, cysteine (CYS). CYS is a known natural precursor of COS and CS2. Results indicated that COS formation did not vary strongly with DOM type, although small impacts were observed on the kinetic patterns. COS formation also increased with increasing CYS concentration but decreased with increasing DOM concentration. Quenching experiments indicated that ˙OH was not involved in the rate-limiting step of COS formation, whereas excited triplet states of DOM (3CDOM*) were plausibly involved, although the quenching agents used to remove 3CDOM* may have reacted with the CYS-derived intermediates as well. CS2 was not formed under any of the experimental conditions. Overall, DOM-containing synthetic waters had a limited to no effect towards forming COS and CS2, especially when compared to the higher concentrations formed in sunlit natural waters, as examined previously. The reasons behind this limited effect need to be explored further but may be due to the additional water quality constituents present in these natural waters. The findings of this study imply that multiple variables beyond DOM govern COS and CS2 photoproduction when moving from freshwaters to open ocean waters.
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Affiliation(s)
| | - Ethan Hain
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Lee Blaney
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Baltimore, MD, USA
| | - Amisha D Shah
- Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana, USA. and Division of Environmental and Ecological Engineering, Purdue University, West Lafayette, Indiana, USA
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Wasswa J, Driscoll CT, Zeng T. Photochemical Characterization of Surface Waters from Lakes in the Adirondack Region of New York. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:10654-10667. [PMID: 32786602 DOI: 10.1021/acs.est.0c02811] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The Adirondack Mountain region of New York, a historical hotspot for atmospheric sulfur and nitrogen deposition, features abundant lakes that are experiencing browning associated with recovery from acidification. Yet, much remains unknown about the photoreactivity of Adirondack lake waters. We quantified the apparent quantum yields (Φapp,RI) of photochemically produced reactive intermediates (RIs), such as excited triplet states of dissolved organic matter (3DOM*), singlet oxygen (1O2), and hydroxyl radicals (•OH), for surface waters collected from 16 representative Adirondack lakes. Φapp,3DOM* and Φapp,1O2 for native Adirondack lake waters fell within ranges reported for whole waters and DOM isolates from various sources, while Φapp,•OH were substantially lower than those measured for other aquatic samples. Orthogonal partial least squares and multiple linear regression analyses identified the spectral slope coefficient from 290 to 400 nm (S290-400) as the most effective predictor of Φapp,RI among measured water chemistry parameters and bulk DOM properties. Φapp,RI also exhibited divergent responses to controlled pH adjustment and aluminum or iron addition simulating hypothetical scenarios relevant to past and future water chemistry conditions of Adirondack lakes. This study highlights the need for continued research on changes in photoreactivity of acid-impacted aquatic ecosystems in response to browning and subsequent impacts on photochemical processes.
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Affiliation(s)
- Joseph Wasswa
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
| | - Teng Zeng
- Department of Civil and Environmental Engineering, Syracuse University, 151 Link Hall, Syracuse, New York 13244, United States
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Removal of As(III) from Water Using the Adsorptive and Photocatalytic Properties of Humic Acid-Coated Magnetite Nanoparticles. NANOMATERIALS 2020; 10:nano10081604. [PMID: 32824146 PMCID: PMC7466695 DOI: 10.3390/nano10081604] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/31/2020] [Accepted: 08/11/2020] [Indexed: 11/17/2022]
Abstract
The oxidation of highly toxic arsenite (As(III)) was studied using humic acid-coated magnetite nanoparticles (HA-MNP) as a photosensitizer. Detailed characterization of the HA-MNP was carried out before and after the photoinduced treatment of As(III) species. Upon irradiation of HA-MNP with 350 nm light, a portion of the As(III) species was oxidized to arsenate (As(V)) and was nearly quantitatively removed from the aqueous solution. The separation of As(III) from the aqueous solution is primarily driven by the strong adsorption of As(III) onto the HA-MNP. As(III) removals of 40–90% were achieved within 60 min depending on the amount of HA-MNP. The generation of reactive oxygen species (•OH and 1O2) and the triplet excited state of HA-MNP (3HA-MNP*) was monitored and quantified during HA-MNP photolysis. The results indicate 3HA-MNP* and/or singlet oxygen (1O2) depending on the reaction conditions are responsible for converting As(III) to less toxic As(V). The formation of 3HA-MNP* was quantified using the electron transfer probe 2,4,6-trimethylphenol (TMP). The formation rate of 3HA-MNP* was 8.0 ± 0.6 × 10−9 M s−1 at the TMP concentration of 50 µM and HA-MNP concentration of 1.0 g L−1. The easy preparation, capacity for triplet excited state and singlet oxygen production, and magnetic separation suggest HA-MNP has potential to be a photosensitizer for the remediation of arsenic (As) and other pollutants susceptible to advanced oxidation.
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Tang G, Zheng X, Li X, Liu T, Wang Y, Ma Y, Ji Y, Qiu X, Wan Y, Pan B. Variation of effluent organic matter (EfOM) during anaerobic/anoxic/oxic (A 2O) wastewater treatment processes. WATER RESEARCH 2020; 178:115830. [PMID: 32335369 DOI: 10.1016/j.watres.2020.115830] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/10/2020] [Accepted: 04/12/2020] [Indexed: 06/11/2023]
Abstract
Here, we studied seasonal variation of effluent organic matter (EfOM), based on molecular weight distribution and fluorescent components, during the traditional anaerobic/anoxic/oxic (A2O) wastewater treatment processes. Microbial community structure and effect of temperature on some isolated pure strains were analyzed to explain the related mechanism. Results showed that the anaerobic process played a key role in EfOM removal by removing building blocks, low molecular weight (LMW) neutrals, biopolymers, and protein-related substances (C4 and C5), thus determining the fate of EfOM during the A2O processes. On the other hand, humic substances, LMW neutrals, large molecular-sized hydrophobic humic-like compounds (C3), and aromatic proteins (C4) were generated during the anoxic process in summer and winter. Proteobacteria (Gamma-, Beta-, and Alpha-proteobacteria) and Bacteroidetes constituted over 50% of the sludge community. Temperature was found to be positively correlated with the generation of soluble microbial products (SMP) based on the performance of the mixture of isolated Herbaspirillum sp. (Beta-proteobacteria) and Pseudomonas sp. (Gamma-proteobacteria). Through comprehensive analysis of the co-action of Proteobacteria and temperature, we proposed the Synergetic Effect of Temperature and Proteobacteria as a possible mechanism of the seasonal variation of EfOM. These findings are important for understanding the fate of EfOM during the wastewater treatment processes and therefore be helpful for better EfOM control.
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Affiliation(s)
- Gang Tang
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China; School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xing Zheng
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China.
| | - Xiaolin Li
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China
| | - Tong Liu
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China
| | - Yan Wang
- Shaanxi Provincial Institute of Microbiology, Xi'an, 710043, China
| | - Yinliang Ma
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China
| | - Yetong Ji
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China; Key Laboratory of Integrated Regulation and Resource Development on Shallow Lake of Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China
| | - Xiaopeng Qiu
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China
| | - Yi Wan
- Shaanxi Provincial Institute of Microbiology, Xi'an, 710043, China
| | - Baozhu Pan
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an, 710048, China
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Chen Y, Hozalski RM, Olmanson LG, Page BP, Finlay JC, Brezonik PL, Arnold WA. Prediction of Photochemically Produced Reactive Intermediates in Surface Waters via Satellite Remote Sensing. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:6671-6681. [PMID: 32383589 DOI: 10.1021/acs.est.0c00344] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Absorption of solar radiation by colored dissolved organic matter (CDOM) in surface waters results in the formation of photochemically produced reactive intermediates (PPRIs) that react with pollutants in water. Knowing the steady-state concentrations of PPRIs ([PPRI]ss) is critical to predicting the persistence of pollutants in sunlit surface waters. CDOM levels (a440) can be measured remotely for lakes over large areas using satellite imagery. Laboratory measurements of [PPRI]ss and apparent quantum yields (Φ) of three PPRIs (3DOM*, 1O2, and •OH) were made for 24 lake samples under simulated sunlight. The total rate of light absorption by the water samples (Ra), the rates of formation (Rf), and [PPRI]ss of 3DOM* and 1O2 linearly increased with increasing a440. The production rate of •OH was linearly correlated with a440, but the steady-state concentration was best fit by a logarithmic function. The relationship between measured a440 and Landsat 8 reflectance was used to map a440 for more than 10 000 lakes across Minnesota. Relationships of a440 with Rf, [PPRIs]ss, and Ra were coupled with satellite-based a440 assessments to map reactive species production rates and concentrations as well as contaminant transformation rates. This study demonstrates the potential for using satellite imagery for estimating contaminant loss via indirect photolysis in lakes.
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Affiliation(s)
- Yiling Chen
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, United States
| | - Raymond M Hozalski
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, United States
| | - Leif G Olmanson
- Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue North, St. Paul, Minnesota 55108-6112, United States
| | - Benjamin P Page
- Water Resources Center, University of Minnesota, 1985 Buford Avenue, St. Paul, Minnesota 55108-6112, United States
| | - Jacques C Finlay
- Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, Minnesota 55108-6097, United States
| | - Patrick L Brezonik
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, United States
| | - William A Arnold
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive SE, Minneapolis, Minnesota 55455-0116, United States
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Wang H, Zhou H, Ma J, Nie J, Yan S, Song W. Triplet Photochemistry of Dissolved Black Carbon and Its Effects on the Photochemical Formation of Reactive Oxygen Species. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:4903-4911. [PMID: 32227921 DOI: 10.1021/acs.est.0c00061] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Dissolved black carbon (DBC) is an important component of dissolved organic matter pool; however, its photochemical properties are not fully understood. In this study, we determined the excited triplet-state quantum yields of DBC (3DBC*) and 1O2 quantum yields (Φ1O2) of six diverse DBCs using sorbic alcohol, 2,4,6-trimethylphenol (TMP), and furfuryl alcohol and compared the results with quantum yields of reference natural organic matters (NOMs). The average Φ1O2 of six DBCs (4.2 ± 1.5%) was greater than that of terrestrial NOM (2.4 ± 0.3%) and comparable to autochthonous NOM (5.3 ± 0.2%). Using TMP as a probe for oxidizing triplets, DBC presented significantly higher apparent quantum yield coefficients for degrading TMP (fTMP) than the reference NOM, reflecting that the fTMP values of low-energy 3DBC* were approximately 12-fold greater than those of low-energy 3NOM*. The differences in the fTMP and Φ1O2 trends among the DBCs indicated that the 3DBC* responsible for these reactions may be from different sources. In addition, DBC was much more effective than NOM, on a carbon-normalized basis, during photodegradation of pharmaceutically active compounds. This result confirms that the presence of DBC can accelerate the photodegradation of contaminants that are susceptible to one-electron oxidation by triplets.
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Affiliation(s)
- Hui Wang
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Huaxi Zhou
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Jianzhong Ma
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Jianxin Nie
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
| | - Shuwen Yan
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, P. R. China
| | - Weihua Song
- Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, P. R. China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, P. R. China
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Bu L, Zhu N, Li C, Huang Y, Kong M, Duan X, Dionysiou DD. Susceptibility of atrazine photo-degradation in the presence of nitrate: Impact of wavelengths and significant role of reactive nitrogen species. JOURNAL OF HAZARDOUS MATERIALS 2020; 388:121760. [PMID: 31810806 DOI: 10.1016/j.jhazmat.2019.121760] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 06/10/2023]
Abstract
The role of reactive nitrogen species (RNS) formed from nitrate photolysis has aroused interests in transformation of contaminants of emerging concern. This study investigated the influence of UV wavelengths (255, 285 and 365 nm) on photolysis of nitrate for degradation of atrazine (ATZ). The UV285/nitrate system showed the fastest rate constant for degradation of ATZ with kobs of 0.0022 cm2 mJ-1. UV photolysis, RNS, and hydroxyl radical (HO) were identified as main contributors to ATZ degradation in UV/nitrate system. Among the contributors, RNS made the major contribution to degradation of ATZ in UV285/nitrate system, while HO is the predominant specie in UV255/nitrate system. Variance decomposition analysis showed that degradation of ATZ was slightly impacted by natural organic matter and carbonate/bicarbonate in UV285/nitrate system but was dramatically affected in UV255/nitrate system. Main transformation products of ATZ in UV285/nitrate system were identified and possible pathways were proposed. RNS were confirmed to be favorable for acceleration of ATZ photolysis through further reaction of RNS with hydroxyatrazine (with electron-rich moieties). Our study provides deep insights on the influence of UV wavelength on nitrate photolysis and ATZ degradation, and provides a novel method for remediation of water co-contaminated by nitrate and organic contaminants.
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Affiliation(s)
- Lingjun Bu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China; Department of Chemical and Environmental Engineering, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA
| | - Ningyuan Zhu
- Department of Chemical and Environmental Engineering, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA; Zigui Ecological Station for Three Gorges Dam Project, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Sciences, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing 210008, China
| | - Chunquan Li
- Department of Chemical and Environmental Engineering, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA; School of Chemical and Environmental Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Ying Huang
- Department of Chemical and Environmental Engineering, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA
| | - Minghao Kong
- Department of Chemical and Environmental Engineering, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA
| | - Xiaodi Duan
- Department of Chemical and Environmental Engineering, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA.
| | - Dionysios D Dionysiou
- Department of Chemical and Environmental Engineering, 705 Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221-0012, USA
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Wu QY, Zhou TH, Du Y, Ye B, Wang WL, Hu HY. Characterizing the molecular weight distribution of dissolved organic matter by measuring the contents of electron-donating moieties, UV absorbance, and fluorescence intensity. ENVIRONMENT INTERNATIONAL 2020; 137:105570. [PMID: 32078873 DOI: 10.1016/j.envint.2020.105570] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/05/2020] [Accepted: 02/09/2020] [Indexed: 06/10/2023]
Abstract
Electron-donating moieties (EDM) have recently been used to characterize the redox properties and treatability of dissolved organic matter during water and wastewater treatment. In this study, size exclusion chromatography followed by a derivatization-spectrometric method was developed to determine the molecular weight (MW) distribution of EDM in dissolved organic matter. The relationships between EDM concentration and chromophore content (indicated by UVA254), fluorophore content (indicated by fluorescence), and dissolved organic carbon (DOC) concentration were analyzed for different MW fractions. In general, natural organic matter (NOM) showed higher total EDM concentration and higher EDM average MW than effluent organic matter (EfOM). For NOM, fractions with MW between 1.8 k and 6.9 k Da accounted for most of the EDM (45.4%-48.6%), followed by the fractions with MW < 1.8 k Da (25.6%-42.4%). By contrast, the EDM in EfOM occurred predominantly in fractions with MW < 1 k Da (51.8%-58.6%), with lower concentrations in fractions with MW > 1.8 k Da (<20.2%). The heterogeneous MW distribution of EDM was strongly correlated to the presence of chromophores, but not DOC or fluorophores. The EDM difference between MW fractions suggested that the fraction with MW 1.8-6.9 k Da (40.7%-47.1%) and the fractions with MW < 1 k Da (50.2%-58.8%) should be the dominant oxidant consumers in NOM and EfOM, respectively. When the EDM was normalized by the DOC for each MW fraction (EDMMW/DOCMW), the EDMMW/DOCMW of relatively high-MW fractions (>1.8 k Da) is 1.2-1.9 times of relatively low-MW (<1 k Da) fractions for both NOM and EfOM, which indicates that higher-MW fractions are more susceptible to chemical oxidations. The relationship between EDM change and UVA254 change varied for different MW fractions during advanced ozonation treatment, because of the different oxidation mechanisms in operation for MW fractions. The ozonation of EfOM fractions with higher MW (>1.8 k Da) and lower MW (<1 k Da) preferentially resulted in benzoquinone formation and ring-cleavage, respectively.
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Affiliation(s)
- Qian-Yuan Wu
- Shenzhen Laboratory of Microorganism Application and Risk Control, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
| | - Tian-Hui Zhou
- Shenzhen Laboratory of Microorganism Application and Risk Control, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, PR China
| | - Ye Du
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| | - Bei Ye
- Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| | - Wen-Long Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China.
| | - Hong-Ying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, PR China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
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Partanen SB, Erickson PR, Latch DE, Moor KJ, McNeill K. Dissolved Organic Matter Singlet Oxygen Quantum Yields: Evaluation Using Time-Resolved Singlet Oxygen Phosphorescence. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3316-3324. [PMID: 32064862 DOI: 10.1021/acs.est.9b07246] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Singlet oxygen (1O2) generation quantum yields from chromophoric dissolved organic matter (CDOM) have been reported for many samples over the past 4 decades. Yet even for standardized isolates such as those from the International Humic Substance Society (IHSS), wide-ranging values exist in the literature. In this manuscript, time-resolved 1O2 phosphorescence was used to determine the 1O2 quantum yields (ΦΔ) of a variety of dissolved organic matter (DOM) isolates and natural waters. In general, the 1O2 quantum yield values in this study are in the middle, although below the median of the range of past reported values (e.g., for Suwannee River Natural Organic Matter IHSS isolate: 1.8% vs 0.23-2.89%). Notably, hydrophobic neutral fractions of DOM isolates were found to possess the highest 1O2 quantum yields, an interesting result given that these fractions are not retained in typical humic and fulvic acid isolation procedures that use XAD resins. The excitation wavelength dependence of 1O2 generation from CDOM was also examined, and an approximate linear decrease with longer excitation wavelength was observed. This work advances the understanding of CDOM photoprocesses, especially in relation to wavelength-dependent 1O2 production, which is valuable for assessing real-world environmental behavior.
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Affiliation(s)
- Sarah B Partanen
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Paul R Erickson
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Douglas E Latch
- Department of Chemistry, Seattle University, Seattle, Washington 98122, United States
| | - Kyle J Moor
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
| | - Kristopher McNeill
- Institute of Biogeochemistry and Pollutant Dynamics (IBP), Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
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Deng H, He H, Sun S, Zhu X, Zhou D, Han F, Huang B, Pan X. Photocatalytic degradation of dye by Ag/TiO 2 nanoparticles prepared with different sol-gel crystallization in the presence of effluent organic matter. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:35900-35912. [PMID: 31707612 DOI: 10.1007/s11356-019-06728-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
TiO2 nanoparticle-doped Ag (Ag/TNPs) have good photocatalytic properties based on localized surface plasmon resonance (LSPR) effect. The effluent organic matter (EfOM) can be easily activated by photo-excitation to promote pollutant photodegradation, but excessive EfOM has an inactive effect. Herein, the purpose of this paper is to investigate the changes of photocatalytic performance by Ag/TNPs in the presence of EfOM. Three Ag/TNPs made by condensation crystallization or rotary evaporation crystallization using the sol-gel method were conducted in photocatalytic degradation of methyl orange (MO). The Ag/TNPs crystallized by condensation had greater separation rate of photogenerated electron-hole pairs and photocatalytic degradation of MO with high load rates of binding Ag and TiO2 than those formed by rotary evaporation crystallization. Indeed, EfOM could be excited to produce the active substances under illumination resulting in the promotion of MO degradation. However, contrary to previous speculation, no additive effect of MO photodegradation was observed with the addition both of EfOM and Ag/TNPs at different pH values (5~9) and ion strength (0~0.4 mol L-1). It can be explained that the EfOM changed the morphology and active sites in Ag/TNPs' surface. Meanwhile, EfOM could be consumed and degraded by Ag/TNP photocatalysis leading to the concentration of free radicals to decrease. This study revealed a nonsynergistic effect between nanomaterial and EfOM for photocatalysis. EfOM would have a negative effect on photocatalytic degradation of organic compounds by Ag/TNPs in the aquatic environment. Graphical abstract .
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Affiliation(s)
- Hongyu Deng
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China
| | - Huan He
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China.
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, 45221, USA.
| | - Shijie Sun
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China
| | - Xintong Zhu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China
| | - Dongxu Zhou
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China
| | - Fengxia Han
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China.
| | - Bin Huang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China
- Yunnan Provincial Key Laboratory of Carbon Sequestration and Pollution Control in Soils, Kunming, 650500, People's Republic of China
| | - Xuejun Pan
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, People's Republic of China
- Yunnan Provincial Key Laboratory of Carbon Sequestration and Pollution Control in Soils, Kunming, 650500, People's Republic of China
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Tian Y, Wei L, Yin Z, Feng L, Zhang L, Liu Y, Zhang L. Photosensitization mechanism of algogenic extracellular organic matters (EOMs) in the photo-transformation of chlortetracycline: Role of chemical constituents and structure. WATER RESEARCH 2019; 164:114940. [PMID: 31401329 DOI: 10.1016/j.watres.2019.114940] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/29/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
The ubiquitous algogenic extracellular organic matters (EOMs) could enhance solar photodegradation of antibiotics such as Chlortetracycline (CTC), however, the role of chemical constituents and structure in their photosensitizing process was not clear. In this paper, EOMs were extracted from chlorella vulgaris (CV-EOMs), scenedesmus meyen (SM-EOMs) and microcystis aeruginosa (MA-EOMs) to explore their photosensitive efficiencies and mechanisms. All of the EOMs showed higher photosensitive efficiencies than natural organic matter (NOM). The quenching assays and competitive kinetics experiments confirmed the dominant role of 3EOMs* in accelerating CTC photodegradation. The quantum yield coefficients of 3EOMs* (fTMP) of CV-EOMs, SM-EOMs, MA-EOMs, NOM were 139.89 ± 5.46, 125.35 ± 4.69, 91.76 ± 3.53, and 72.84 ± 4.45 L/(mol-photon), respectively. Specific chemical constituents and structure of EOMs were characterized by nuclear magnetic resonance (NMR), fourier transform ion cyclotron resonance mass spectrometry (FT-CIR-MS) and X-ray photoelectron spectroscopy (XPS). The results showed the positive linear correlation of fTMP with content of carbonyl groups in EOMs. In addition, reduction of carbonyl groups in EOMs by NaBH4 significantly decreased CTC photodegradation rate. Density Functional Theory (DFT) calculation suggested the susceptible excitation of carbonyl groups in EOMs under solar light was ascribed to the lowest required energy of electronic transition from HOMO to LUMO (assigned as n-π* transition). The energy of triplet excited-states benzophenone, p-methoxy acetophenone and acetophenone (the EOMs model compounds) was calculated to be 284.92, 288.85 and 265.50 kJ/mol, which were higher than that of CTC (i.e., 217.46 kJ/mol), indicating the energy transfer from excited triplet state to excited triplet state CTC was possible. This study provided mechanism insights into photosensitization effects of allogenic EOMs on photochemical fate of pollutants in aqueous environment.
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Affiliation(s)
- Yajun Tian
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Lianxue Wei
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Ze Yin
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Li Feng
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China
| | - Lirong Zhang
- Chinese Academy of Environment Planning, Beijing, 100012, China
| | - Yongze Liu
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China.
| | - Liqiu Zhang
- Beijing Key Laboratory for Source Control Technology of Water Pollution, Engineering Research Center for Water Pollution Source Control and Eco-remediation, Beijing Forestry University, Beijing, 100083, China.
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Wenk J, Nguyen MT, Nelson KL. Natural Photosensitizers in Constructed Unit Process Wetlands: Photochemical Characterization and Inactivation of Pathogen Indicator Organisms. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:7724-7735. [PMID: 31149822 DOI: 10.1021/acs.est.9b01180] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Dissolved organic matter (DOM) is a natural photosensitizer that contributes to the inactivation of microbial pathogens. In constructed treatment wetlands with open water areas DOM can promote sunlight disinfection of wastewater effluent, but a better understanding of DOM spectroscopic and photochemical properties and how they are impacted by different unit process wetlands is needed to inform design. The goals of this study were: (1) to investigate whether DOM isolates realistically represent the photochemistry of the source DOM in its original water and (2) to observe how changes of DOM along a treatment wetland affect its photochemistry, including pathogen inactivation. A pilot scale unit process wetland was studied that consisted of three different cells (open water, cattail, and bulrush) fed by secondary wastewater effluent. DOM was isolated using solid-phase extraction (SPE), photochemically characterized, and compared to the original water samples and standard DOMs. For MS2 coliphage, a virus indicator, the most efficient photosensitizer was the wastewater DOM isolated from the influent of the wetland, while for the bacterial indicator Enterococcus faecalis, inactivation results were comparable across wetland isolates. SPE resulted in isolation of 47% to 59% of whole water DOM and enriched for colored DOM. Singlet oxygen precursors were efficiently isolated, while some excited triplet state precursors remained in the extraction discharge. DOM processing indicators such as SUVA254, SUVA280, and spectral slopes including E2/ E3 ratios were reflected in the isolates. Photoinactivation of MS2 was significantly lower in both the reconstituted water samples and isolates compared to the original water sample, possibly due to disturbance of the trans-molecular integrity of DOM molecules by SPE that affects distance between MS2 and DOM sites with locally higher singlet oxygen production. For E. faecalis, results were similar in original water samples and isolates. Higher sorption of DOM to E. faecalis was roughly correlated with higher photoinactivation rates. To enhance sunlight disinfection in unit process wetlands, there is no advantage to placing open water cells after vegetated cells, as passage through the vegetated cells led to increased light absorption and lower singlet oxygen and triplet-state quantum yields and steady state concentrations.
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Affiliation(s)
- Jannis Wenk
- Department of Civil & Environmental Engineering , University of California , Berkeley , California 94720-1710 , United States
- Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt) Engineering Research Center (ERC) , University of California , Berkeley , California 94720-1710 , United States
| | - Mi T Nguyen
- Department of Civil & Environmental Engineering , University of California , Berkeley , California 94720-1710 , United States
- Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt) Engineering Research Center (ERC) , University of California , Berkeley , California 94720-1710 , United States
| | - Kara L Nelson
- Department of Civil & Environmental Engineering , University of California , Berkeley , California 94720-1710 , United States
- Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt) Engineering Research Center (ERC) , University of California , Berkeley , California 94720-1710 , United States
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