1
|
Liu H, Tu YN, Lei Y, Zhou D, Zhao Q, Li Y, Pan W. Photochemistry of plateau lake-derived dissolved organic matter: Reactive species generation and effects on 17β-estradiol photodegradation. JOURNAL OF HAZARDOUS MATERIALS 2024; 473:134615. [PMID: 38761768 DOI: 10.1016/j.jhazmat.2024.134615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/18/2024] [Accepted: 05/12/2024] [Indexed: 05/20/2024]
Abstract
Naturally strong ultraviolet irradiation at high altitudes causes photobleaching of plateau lake DOM (P-DOM) and affects its photochemical activity. However, the photoreactivity of P-DOM has remained unclear under natural photobleaching condition. Here, six P-DOM samples isolated from plateau lakes in Yunnan Province, China as well as two reference DOM as comparisons were used to explore the photogeneration of reactive species (RS) and their effects on 17β-estradiol photodegradation. Compared with SRHA/SRFA, P-DOM has lower aromaticity, average molecular weight, and electron-donating capacity. The quantum yields of triplet state P-DOM (3P-DOM*), 1O2, and ∙OH produced in P-DOM solutions were greatly higher than those of reference DOM. The RS quantum yields had positive linear correlations with E2/E3 and SR, whereas were negatively linear correlated with SUVA25. Radical quenching experiments showed that 3P-DOM* was the prominent RS for 17β-estradiol photodegradation, and its contribution exceeded 70% for each of P-DOM. 3P-DOM*-mediated photodegradation was mainly attributed to the electron-transfer reactions with an average second-order rate constant of 4.62 × 109 M-1s-1, indicating the strong photoreactivity towards 17β-estradiol. These findings demonstrate that P-DOM is an efficient photosensitizer for RS production, among which 3P-DOM* may play an important role in enhanced photodegradation for organic micropollutants in plateau lake enriched with DOM.
Collapse
Affiliation(s)
- Huaying Liu
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Yi-Na Tu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Yajie Lei
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Die Zhou
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| | - Qilin Zhao
- Yunnan Environmental Monitoring Center, Kunming, Yunnan 650034, China
| | - Yingjie Li
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China.
| | - Wenjiao Pan
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China
| |
Collapse
|
2
|
Peng J, Pan Y, Zhou Y, Lei X, Guo Y, Lei Y, Kong Q, Cheng S, Yang X. Mechanistic Aspects of Photodegradation of Deoxynucleosides Induced by Triplet State of Effluent Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:4751-4760. [PMID: 38324714 DOI: 10.1021/acs.est.3c08782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Excited triplet states of wastewater effluent organic matter (3EfOM*) are known as important photo-oxidants in the degradation of extracellular antibiotic resistance genes (eArGs) in sunlit waters. In this work, we further found that 3EfOM* showed highly selective reactivity toward 2'-deoxyguanosine (dG) sites within eArGs in irradiated EfOM solutions at pH 7.0, while it showed no photosensitizing capacity toward 2'-deoxyadenosine, 2'-deoxythymidine, and 2'-deoxycytidine (the basic structures of eArGs). The 3EfOM* contributed to the photooxidation of dG primarily via one-electron transfer mechanism, with second-order reaction rate constants of (1.58-1.74) × 108 M-1 s-1, forming the oxidation intermediates of dG (dG(-H)•). The formed dG(-H)• could play a significant role in hole hopping and damage throughout eArGs. Using the four deoxynucleosides as probes, the upper limit for the reduction potential of 3EfOM* is estimated to be between 1.47 and 1.94 VNHE. Compared to EfOM, the role of the triplet state of terrestrially natural organic matter (3NOM*) in dG photooxidation was minor (∼15%) mainly due to the rapid reverse reactions of dG(-H)• by the antioxidant moieties of NOM. This study advances our understanding of the difference in the photosensitizing capacity and electron donating capacity between NOM and EfOM and the photodegradation mechanism of eArGs induced by 3EfOM*.
Collapse
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, P. R. 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, P. R. China
- School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - 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, P. R. China
| | - Xin Lei
- Yunnan Provincial Key Laboratory of Soil Carbon Sequestration and Pollution Control, Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650500, P. R. China
| | - Yifan Guo
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, P. R. China
| | - Yu Lei
- Key Laboratory of Photochemistry, Institute of Chemistry Chinese Academy of Sciences, Beijing National Laboratory for Molecular Sciences, Beijing 100190, P. R. 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, P. R. 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, P. R. 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, P. R. China
| |
Collapse
|
3
|
Li L, Cheng W, Xie X, Zhao R, Wang Y, Wang Z. Photo-Reactivity of dissolved black carbon unveiled by combination of optical spectroscopy and FT-ICR MS analysis: Effects of pyrolysis temperature. WATER RESEARCH 2024; 251:121138. [PMID: 38244298 DOI: 10.1016/j.watres.2024.121138] [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: 09/17/2023] [Revised: 12/29/2023] [Accepted: 01/14/2024] [Indexed: 01/22/2024]
Abstract
Dissolved black carbon (DBC) has high photoactivity, which plays an important role in contaminants photodegradation. However, it is unclear how pyrolysis temperatures would affect the composition and photo-reactivity of DBC at the molecular level. Herein, we combined complementary techniques to study the characteristics of DBC pyrolyzed at 200 - 500 ℃, as well as the photoproduction of reactive species and the photodegradation of tetracycline (TC). Bulk composition characterization found that condensed aromatic carbonyl compounds (ConAC) with narrow molecular weights in DBC experienced an increase from 200 to 500 °C, which enhanced the photoproduction of 3DBC*,1O2, and ·OH. Molecular-level data suggested that 3DBC* and 1O2 were both related to the same DBC compounds. Comparatively, the patterns for ·OH were less pronounced, implying its precursor was not 3DBC* and had more complexity. Plentiful CHOx species of ConAC in DBC400 and DBC500 (DBCT, where T = pyrolysis temperature) accelerated the generation of 3DBC* and 1O2, enhancing the photodegradation of TC, and mainly triplet states of quinones reacted with TC. In contrast, DBC200 and DBC300 exhibited inhibition since massive CHOx species in lignin-like reduced 3TC* to TC. Our data revealed the diverse photochemical behavior mechanisms of DBC pyrolyzed at 200 - 500 ℃ at the molecular level and the implications for aquatic contaminants photochemistry.
Collapse
Affiliation(s)
- Liangyu Li
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Wan Cheng
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Xiaoyun Xie
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
| | - Ranran Zhao
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Yaodong Wang
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Zhaowei Wang
- Key Laboratory for Environmental Pollution Prediction and Control, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, China.
| |
Collapse
|
4
|
Powers LC, Schmitt-Kopplin P, Gonsior M. Evaluating the photochemical reactivity of disinfection byproducts formed during seawater desalination processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169292. [PMID: 38104835 DOI: 10.1016/j.scitotenv.2023.169292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/04/2023] [Accepted: 12/09/2023] [Indexed: 12/19/2023]
Abstract
Reverse osmosis (RO) is widely used for seawater desalination but pre-chlorination of intake water produces halogenated disinfection byproducts (DBPs). The fate and environmental impacts associated with the discharge of DBP-containing RO brine wastewater are unknown. Therefore, to evaluate if photochemistry plays a role in DBP degradation in seawater, we collected samples at a desalination plant, which were desalted and concentrated using two-inline solid phase extraction (SPE) techniques combining reverse-phase polymeric (PPL) and weak anion exchange (WAX) resins. Both filtered water samples and SPE samples (extracts reconstituted in open ocean seawater) were exposed to simulated sunlight in a custom-built flow-through system. Optical property analysis during irradiation experiments did not provide distinguishing features between intake water and RO reject water (brine). Extractable organic bromine (organoBr) concentrations were low in intake water samples (7.8 μg Br L-1) and did not change significantly due to irradiation. OrganoBr concentrations in laboratory-chlorinated raw water were much higher (135 μg Br L-1) and on average decreased by 42 % after 24 h irradiation. However, while organoBr concentrations were highest in RO reject water (473 μg Br L-1), changes in organoBr concentrations in PPL SPE samples after 24 h irradiation were variable, ranging from a 1-46 % loss. Furthermore, most bromine-containing molecular ions identified by high resolution mass spectrometry that were present in RO reject water before irradiation were also found after both 24 h and 50 h exposures. Although only one RO reject water sample was tested in this study, results highlight that hundreds of yet to be identified brominated DBPs in RO reject water could be resistant to photodegradation or phototransform into existing DBPs in the environment. Future work examining the biolability of DBPs in RO reject water, as well as the interplay between photochemical and biological DBP cycling, is warranted.
Collapse
Affiliation(s)
- Leanne C Powers
- Department of Chemistry, State University of New York College of Environmental Science and Forestry, Syracuse, NY, United States.
| | - Philippe Schmitt-Kopplin
- Helmholtz Munich, Research Unit Analytical BioGeoChemistry, Munich, Germany; Chair of Analytical Food Chemistry, Technical University München, Munich, Germany; Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, United States
| | - Michael Gonsior
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, United States
| |
Collapse
|
5
|
Han J, Zhai H, Zhang X, Liu J, Sharma VK. Effects of ozone dose on brominated DBPs in subsequent chlor(am)ination: A comprehensive study of aliphatic, alicyclic and aromatic DBPs. WATER RESEARCH 2024; 250:121039. [PMID: 38142503 DOI: 10.1016/j.watres.2023.121039] [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: 07/27/2023] [Revised: 12/11/2023] [Accepted: 12/18/2023] [Indexed: 12/26/2023]
Abstract
Ozone‒chlor(am)ine is a commonly used combination of disinfectants in drinking water treatment. Although there are quite a few studies on the formation of some individual DBPs in the ozone‒chlor(am)ine disinfection, an overall picture of the DBP formation in the combined disinfection is largely unavailable. In this study, the effects of ozone dose on the formation and speciation of organic brominated disinfection byproducts (DBPs) in subsequent chlorination, chloramination, or chlorination‒chloramination of simulated drinking water were investigated. High-molecular-weight, aliphatic, alicyclic and aromatic brominated DBPs were selectively detected and studied using a powerful precursor ion scan method with ultra performance liquid chromatography/electrospray ionization triple quadrupole mass spectrometry (UPLC/ESI-tqMS). Two groups of unregulated yet relatively toxic DBPs, dihalonitromethanes and dihaloacetaldehydes, were detected by the UPLC/ESI-tqMS for the first time. With increasing ozone dose, the levels of high-molecular-weight (m/z 300-500) and alicyclic and aromatic brominated DBPs generally decreased, the levels of brominated aliphatic acids were slightly affected, and the levels of dihalonitromethanes and dihaloacetaldehydes generally increased in the subsequent disinfection processes. Despite different molecular compositions of the detected DBPs, increasing ozone dose generally shifted the formation of DBPs from chlorinated ones to brominated analogues in the subsequent disinfection processes. This study provided a comprehensive analysis of the impact of ozone dose on the DBP formation and speciation in subsequent chlor(am)ine disinfection.
Collapse
Affiliation(s)
- Jiarui Han
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Hongyan Zhai
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China.
| | - Xiangru Zhang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China.
| | - Jiaqi Liu
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China; Department of Environmental and Occupational Health, Texas A&M University, TX, USA
| | - Virender K Sharma
- Department of Environmental and Occupational Health, Texas A&M University, TX, USA
| |
Collapse
|
6
|
He H, Sun N, Li L, Zhou H, Hu A, Yang X, Ai J, Jiao R, Yang X, Wang D, Zhang W. Photochemical Transformation of Dissolved Organic Matter in Surface Water Augmented the Formation of Disinfection Byproducts. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 38329881 DOI: 10.1021/acs.est.3c08155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
Sunlight may lead to changes in disinfection byproducts (DBPs) formation potentials of source water via transforming dissolved organic matter (DOM); however, the underlying mechanisms behind these changes remain unclear. This work systematically investigated the effect of photochemical transformation of DOM from reservoir water (DOMRe) and micropolluted river water (DOMRi) after 36 h of simulated sunlight irradiation (equivalent to one month under natural sunlight) on DBPs formation. Upon irradiation, high molecular weight (MW) and aromatic molecules tended to be mineralized or converted into low-MW and highly oxidized (O/C > 0.5) ones which might react with chlorine to generate high levels of DBPs, resulting in an elevation in the yields (μg DBP/mg C) of almost all the measured DBPs and the quantities of unknown DBPs in both DOM samples after chlorination. Additionally, DOMRi contained more aromatic molecules susceptible to photooxidation than DOMRe. Consequently, irradiated DOMRi exhibited a greater increase in the formation potentials of haloacetonitriles, halonitromethanes, and specific regulated DBPs, with nitrogenous DBPs being responsible for the overall rise in the calculated cytotoxicity following chlorination. This work emphasized the importance of a comprehensive removal of phototransformation products that may serve as DBPs precursors from source waters, especially from micropolluted source waters.
Collapse
Affiliation(s)
- Hang He
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 Hubei, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Niannian Sun
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Lanfeng Li
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Hao Zhou
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Aibin Hu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Xiaoyin Yang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
| | - Jing Ai
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ruyuan Jiao
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Xiaofang Yang
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Dongsheng Wang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058 Zhejiang, China
| | - Weijun Zhang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, 430074 Hubei, China
- National Engineering Research Center of Industrial Wastewater Detoxication and Resource Recovery, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| |
Collapse
|
7
|
Wan D, Song G, Mi W, Tu X, Zhao Y, Bi Y. Insights into the Enhanced Photogeneration of Hydroxyl Radicals from Chlorinated Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:805-815. [PMID: 38156625 DOI: 10.1021/acs.est.3c08257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Free available chlorine has been and is being applied in global water treatment and readily reacts with dissolved organic matter (DOM) in aquatic environments, leading to the formation of chlorinated products. Chlorination enhances the photoreactivity of DOM, but the influence of chlorinated compounds on the photogeneration of hydroxyl radicals (•OH) has remained unexplored. In this study, a range of chlorinated carboxylate-substituted phenolic model compounds were employed to assess their •OH photogeneration capabilities. These compounds demonstrated a substantial capacity for •OH production, exhibiting quantum yields of 0.1-5.9 × 10-3 through direct photolysis under 305 nm and 0.2-9.5 × 10-3 through a triplet sensitizer (4-benzoylbenzoic acid)-inducing reaction under 365 nm LED irradiation. Moreover, the chlorinated compounds exhibited higher light absorption and •OH quantum yields compared to those of their unchlorinated counterparts. The •OH photogeneration capacity of these compounds exhibited a positive correlation with their triplet state one-electron oxidation potentials. Molecular-level compositional analysis revealed that aromatic structures rich in hydroxyl and carboxyl groups (e.g., O/C > 0.5 with H/C < 1.5) within DOM serve as crucial sources of •OH, and chlorination of these compounds significantly enhances their capacity to generate •OH upon irradiation. This study provides novel insights into the enhanced photogeneration of •OH from chlorinated DOM, which is helpful for understanding the fate of trace pollutants in chlorinated waters.
Collapse
Affiliation(s)
- Dong Wan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Gaofei Song
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Wujuan Mi
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Xiaojie Tu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Yafei Zhao
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| | - Yonghong Bi
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, P. R. China
| |
Collapse
|
8
|
Allen A, Cheng K, McKay G. Evaluating the pH-dependence of DOM absorbance, fluorescence, and photochemical production of singlet oxygen. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2023; 25:1974-1985. [PMID: 37971490 DOI: 10.1039/d3em00316g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The protonation state of dissolved organic matter (DOM) impacts its structure and function in natural and engineered environmental systems, including DOM's ability to absorb light and form photochemically produced reactive intermediates (PPRI). However, the impacts of pH on DOM optical properties and PPRI formation have largely been evaluated separately, with less information being available on their interrelationship as a function of pH for the same set of samples. It is also unclear whether the impact of pH on optical spectra and associated optical surrogates for molecular size (e.g., E2 : E3) of DOM isolates is representative of the behavior of whole water samples. To address these knowledge gaps, spectral pH titrations were performed for seven humic substance and natural organic matter isolates, three whole water samples, and three model compounds. Comparison of the fractional and differential absorption and fluorescence spectra between DOM isolates, whole water samples, and model compounds revealed similar spectral features between all samples. The results show that spectral features observed for DOM isolates also occur for whole water samples, which suggests that there is overlap in the types of chromophores present in DOM isolates and whole waters. Although results from model compounds overlapped with DOM, especially in the ultraviolet region of the spectrum, no model compound replicated DOM's pH dependence perfectly. By measuring apparent quantum yields of singlet oxygen (ΦΔ), we show that aquatic DOM isolates exhibit a different pH-dependence (ΦΔ ∝ pH-1) than soil-derived humic acid isolates (ΦΔ ∝ pH). For aquatic DOM isolates, ΦΔ values measured at different pH were not correlated to apparent fluorescence quantum yields (Φf), suggesting that pH impacts singlet and triplet excited state DOM dynamics in different ways. In contrast, the proportional relationship between Φf and ΦΔ with increasing pH for soil humic acid isolates suggests that pH impacts singlet and triplet excited DOM in these samples in a similar fashion.
Collapse
Affiliation(s)
- Anya Allen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, TX 77843, USA.
| | - Kai Cheng
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, TX 77843, USA.
| | - Garrett McKay
- Zachry Department of Civil & Environmental Engineering, Texas A&M University, College Station, TX 77843, USA.
| |
Collapse
|
9
|
Yin Z, Liu S, Tian Z, Zhao X, He J, Wang C. Carbon-based nanomaterials mediated adsorption and photodegradation of typical organic contaminants in aqueous fulvic acid solution. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2023; 88:1863-1874. [PMID: 37831001 PMCID: wst_2023_300 DOI: 10.2166/wst.2023.300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
In this work, the formation of carbon-based nanomaterials-fulvic acid (CNMs-FA) composites and their capacities for the adsorption and photodegradation of typical organic contaminants in aqueous solutions were investigated. The results suggested that the formation of CNMs-FA composites was dominated by adsorbing FA on CNMs via the physisorption process, which fit the pseudo-first-order kinetic model and the Langmuir isotherm model. The formed CNMs-FA composites were characterized by using the Brunauer-Emmett-Teller, scanning electron microscopy, and infrared spectroscopy techniques and further applied for examining their effects on the adsorption and photodegradation of selected organic contaminants in aqueous solutions. The adsorption of organic contaminants on CNMs-FA composites is mainly involved in hydrogen bonding and electrostatic interactions between organic contaminants and FA species adhering to CNMs. In addition, the CNMs-FA composites are able to promote the photosensitive degradation of organic contaminants due to the photogenerated reactive species including ROS and CNMs-3FA* under sunlight irradiation. This study provided a deeper and more comprehensive understanding of the environmental behavior of CNMs in real natural surface water and clarified the underlying mechanisms.
Collapse
Affiliation(s)
- Zhiming Yin
- College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China E-mail:
| | - Siyu Liu
- College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China
| | - Zhen Tian
- College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China
| | - Xinyue Zhao
- College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China
| | - Jun He
- Department of Chemical and Environmental Engineering, University of Nottingham-Ningbo China, Ningbo 315100, China
| | - Chengjun Wang
- College of Resources and Environment, South-Central Minzu University, Wuhan 430074, China
| |
Collapse
|
10
|
Cai Y, Li X, Feng M, Chovelon JM, Zhou L, Lu J, Chen J, Ji Y. Formation of halogenated chloroxylenols through chlorination and their photochemical activity. WATER RESEARCH 2023; 243:120366. [PMID: 37494746 DOI: 10.1016/j.watres.2023.120366] [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: 05/20/2023] [Revised: 07/12/2023] [Accepted: 07/14/2023] [Indexed: 07/28/2023]
Abstract
Trace organic contaminants usually go through multiple treatment units in a modern water treatment train. Structural modification triggered by pretreatment (e.g., prechlorination) may influence the further transformation and fate of contaminants in downstream units. However, knowledge on this aspect is still limited. In this contribution, we investigated the chlorination of chloroxylenol (PCMX), an antimicrobial agent extensively used during COVID-19 pandemic, and the photoreactivity of its halogenated derivatives. Results indicate that chlorination of PCMX mainly proceeded through electrophilic substitution to give chlorinated products, including Cl- and 2Cl-PCMX. The presence of bromide (Br-) resulted in brominated analogues. Owing to the bathochromic and "heavy atom" effects of halogen substituents, these products show increased light absorption and photoreactivity. Toxicity evaluation suggest that these halo-derivatives have higher persistence, bioaccumulation, and toxicity (PBT) than the parent PCMX. Results of this contribution advance our understanding of the transformation of PCMX during chlorination and the photochemical activity of its halogenated derivatives in subsequent UV disinfection process or sunlit surface waters.
Collapse
Affiliation(s)
- Yan Cai
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaoci Li
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Mingbao Feng
- College of the Environment & Ecology, Xiamen University, Xiamen, 361102, China
| | - Jean-Marc Chovelon
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON, F-69626, Villeurbanne, France
| | - Lei Zhou
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Processes, School of Resources & Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
| | - Junhe Lu
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jing Chen
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuefei Ji
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
| |
Collapse
|
11
|
Yang T, Huang C, An L, Zeng G, Li J, Liu C, Xu X, Jia J, Ma J. The overlooked role of Cr(VI) in micropollutant degradation under solar light irradiation. WATER RESEARCH 2023; 242:120309. [PMID: 37451190 DOI: 10.1016/j.watres.2023.120309] [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: 02/12/2023] [Revised: 06/30/2023] [Accepted: 07/03/2023] [Indexed: 07/18/2023]
Abstract
Hexavalent chromium (Cr(VI)) is ubiquitous in natural environments, whereas its role in the transformation of coexisting contaminants may have been overlooked. In this work, it was reported for the first time that the irradiation of Cr(VI) by solar light (solar light/Cr(VI) system) could effectively degrade various micropollutants with different structures. The removal efficiency of selected micropollutants was increased by 13.3-64.8% by the solar light/Cr(VI) system compared to that by direct solar photolysis. Meanwhile, the oxidation rates were enhanced by 2.2-21.5 folds, while they were negligible by Cr(VI) oxidation alone. Experiments by specific scavengers, probe compounds, fluorescence absorbance, and electron spin resonance analysis demonstrated that hydroxyl radical (•OH) was the major reactive species in the solar light/Cr(VI) system. Further experiments showed that the generation of •OH was closely related to the intermediate Cr(V) generated from Cr(VI) reduction, and Cr(V) could be re-oxidized back to Cr(VI). Increasing solution pH negatively affected model micropollutant (carbamazepine (CBZ)) degradation by the solar light/Cr(VI) system, mainly due to the decreased quantum yield of •OH at higher pH. Coexisting sulfate ions showed negligible effect on CBZ degradation in the solar light/Cr(VI) system, while the presence of bicarbonate, chloride, and humic acid inhibited CBZ degradation to varying degrees, owing to their diverse scavenging effects on •OH. Furthermore, moderate CBZ degradation was also achieved by natural solar light photolysis of Cr(VI). This study demonstrated the pivotal role of Cr(VI) in the transformation of micropollutants under solar irradiation, which advances the understanding of the fate of micropollutants in natural environments.
Collapse
Affiliation(s)
- Tao Yang
- School of Biotechnology and Health Science, Wuyi University, Jiangmen, Guangdong Province 529020, PR China.
| | - Cui Huang
- School of Biotechnology and Health Science, Wuyi University, Jiangmen, Guangdong Province 529020, PR China
| | - Linqian An
- School of Biotechnology and Health Science, Wuyi University, Jiangmen, Guangdong Province 529020, PR China
| | - Ge Zeng
- School of Biotechnology and Health Science, Wuyi University, Jiangmen, Guangdong Province 529020, PR China
| | - Juan Li
- Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhu Hai 519087, PR China.
| | - Changyu Liu
- School of Biotechnology and Health Science, Wuyi University, Jiangmen, Guangdong Province 529020, PR China
| | - Xiaolong Xu
- School of Biotechnology and Health Science, Wuyi University, Jiangmen, Guangdong Province 529020, PR China
| | - Jianbo Jia
- School of Biotechnology and Health Science, Wuyi University, Jiangmen, Guangdong Province 529020, PR China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, PR China
| |
Collapse
|
12
|
Du B, Fan G, Yang S, Luo J, Wu J, Xu KQ. Mechanistic insight into humic acid-enhanced sonophotocatalytic removal of 17β-estradiol: Formation and contribution of reactive intermediates. ENVIRONMENTAL RESEARCH 2023; 231:116249. [PMID: 37247656 DOI: 10.1016/j.envres.2023.116249] [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: 11/02/2022] [Revised: 05/14/2023] [Accepted: 05/26/2023] [Indexed: 05/31/2023]
Abstract
In this study, humic acid (HA) enhanced 17β-estradiol (17β-E2) degradation by Er3+-CdS/MoS2 (ECMS) was investigated under ultrasonic and light conditions. The degradation reaction rate of 17β-E2 was increased from (14.414 ± 0.315) × 10-3 min-1 to (122.677 ± 1.729) × 10-3 min-1 within 90 min sonophotocatalytic (SPC) reaction with the addition of HA. The results of quenching coupled with chemical probe experiments indicated that more reactive intermediates (RIs) including reactive oxygen species (ROSs) and triplet-excited states were generated in the HA-enhanced sonophotocatalytic system. The triplet-excited states of humic acid (3HA*), hydroxyl radical (•OH), and superoxide radical (•O2-) were the dominant RIs for 17β-E2 elimination. In addition, the energy- and electron-transfer process via coexisting HA also account for 12.86% and 29.24% contributions, respectively. The quantum yields of RIs in the SPC-ECMS-HA system followed the order of 3HA* > H2O2 > 1O2 > •O2-> •OH. Moreover, the spectral and fluorescence characteristics of HA were further analyzed during the sonophotocatalytic reaction process. The study expanded new insights into the comprehension of the effects of omnipresent coexisting HA and RIs formation for the removal of 17β-E2 during the sonophotocatalytic process.
Collapse
Affiliation(s)
- Banghao Du
- College of Civil Engineering, Fuzhou University, Fuzhou, 350116, Fujian, China
| | - Gongduan Fan
- College of Civil Engineering, Fuzhou University, Fuzhou, 350116, Fujian, China; State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou, 350002, Fujian, China; Fujian Provincial Key Laboratory of Electrochemical Energy Storage Materials, Fuzhou, 350002, Fujian, China.
| | - Shangwu Yang
- College of Civil Engineering, Fuzhou University, Fuzhou, 350116, Fujian, China
| | - Jing Luo
- Fujian Jinhuang Environmental Sci-Tech Co., Ltd, Fuzhou, 350002, Fujian, China
| | - Jiaxin Wu
- Fujian Province Water Survey & Design Co., Ltd, Fuzhou, 350002, Fujian, China
| | - Kai-Qin Xu
- College of Civil Engineering, Fuzhou University, Fuzhou, 350116, Fujian, China
| |
Collapse
|
13
|
Cai T, Zhang X, Zhang S, Ming Y, Zhang Q. Photochemical behaviors of dissolved organic matter in aquatic environment: Generation, characterization, influencing factors and practical application. ENVIRONMENTAL RESEARCH 2023; 231:116174. [PMID: 37209983 DOI: 10.1016/j.envres.2023.116174] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 04/05/2023] [Accepted: 05/15/2023] [Indexed: 05/22/2023]
Abstract
Dissolved organic matter (DOM) widely exists in aquatic environment and plays a critical role in environmental photochemical reaction. The photochemical behaviors of DOM in sunlit surface waters have received widely attention because its photochemical effects for some coexisted substances in aquatic environment, especially for organic micropollutants degradation. Therefore, to gain a comprehensive understanding of the photochemical properties and environmental effects of DOM, we reviewed the influence of sources on the structure and composition of DOM with relevant identified techniques to analysis functional groups. Additionally, identification and quantification for reactive intermediates are discussed with a focus on influencing factors to produce reactive intermediates by DOM under solar irradiation. These reactive intermediates can promote the photodegradation of organic micropollutants in the environmental system. In future, attention should be paid to the photochemical properties of DOM and environmental effects in real environmental system and development of advanced techniques to study DOM.
Collapse
Affiliation(s)
- Tong Cai
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, 200241, Shanghai, China
| | - Xiaotong Zhang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, 200241, Shanghai, China
| | - Shudong Zhang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, 200241, Shanghai, China
| | - Yuanbo Ming
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, 200241, Shanghai, China
| | - Qiuzhuo Zhang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, School of Ecological and Environmental Sciences, East China Normal University, 200241, Shanghai, China; Institute of Eco-Chongming (IEC), 3663 N. Zhongshan Rd., Shanghai, 200062, China; Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, 3663 N. Zhongshan Road, Shanghai, 200062, China.
| |
Collapse
|
14
|
An Y, Ma XY, Chen W, Li W, Yang S, Chen R, Wang XC. The impact of inorganic ions on the solar photolysis of chlorinated dissolved organic matter from different sources: Spectral characteristics, disinfection byproducts, and biotoxicities. JOURNAL OF HAZARDOUS MATERIALS 2023; 451:131135. [PMID: 36889069 DOI: 10.1016/j.jhazmat.2023.131135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/02/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Dissolved organic matter (DOM) from wastewater treatment plant (WWTP) effluent is chlorinated and then discharged into natural waters, where it is subject to solar irradiation. However, the impacts of inorganic ions in natural waters on the photochemical transformations of the chlorinated DOM (DOM-Cl) have not been studied comprehensively. In this study, variations in the spectral characteristics, disinfection byproducts (DBPs), and biotoxicities of DOM-Cl under solar irradiation at different pH values and in the presence of NO3- and HCO3- were revealed. Three sources of DOM, including DOM from a WWTP effluent, natural organic matter from the Suwannee River, and DOM from plant leaf leachate, were investigated. Solar irradiation resulted in the oxidation of the highly reactive aromatic structures and then reduced the amounts of chromophoric and fluorescent DOM, especially under alkaline conditions. Moreover, alkaline conditions significantly promoted the detected DBPs degradation and the biotoxicities attenuation, while NO3- and HCO3- generally impeded them (or did not work). Dehalogenation of the unknown halogenated DBPs and photolysis of the nonhalogenated organics were the main mechanisms for the DOM-Cl biotoxicity reductions. Hence, improving the ecological safety of WWTP effluents could be achieved through solar irradiation by removing the DBPs formed.
Collapse
Affiliation(s)
- Yali An
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Xiaoyan Y Ma
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China.
| | - Wenfeng Chen
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Wei Li
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Siyan Yang
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Rong Chen
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| | - Xiaochang C Wang
- Key Lab of Environmental Engineering (Shaanxi province), School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Key Laboratory of Northwest Water Resource, Environment and Ecology (Ministry of Education), Xi'an University of Architecture and Technology, No.13 Yanta Road, Xi'an 710055, PR China
| |
Collapse
|
15
|
Chen C, Zhao X, Chen H, Li M, Cao L, Wang Y, Xian Q. Degradation of natural organic matter and disinfection byproducts formation by solar photolysis of free available chlorine. WATER RESEARCH 2023; 239:120020. [PMID: 37167852 PMCID: PMC10149525 DOI: 10.1016/j.watres.2023.120020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 04/26/2023] [Accepted: 04/29/2023] [Indexed: 05/13/2023]
Abstract
Environment disinfection effectively curbs transmission of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). However, elevated concentration of free available chlorine (FAC) in disinfectants can be discharged into surface water, generating toxic disinfection byproducts (DBPs). The impact of solar photolysis of FAC on natural organic matter (NOM) to form DBPs has not been well studied. In this work, solar photolysis of FAC was found to result in higher formation of DBPs, DBPs formation potential (DBPsFP), total organic chlorine (TOCl) and lower specific ultraviolet absorbance at 254 nm (SUVA254), compared to dark chlorination. In solar photolysis of FAC, formation of total DBPs was promoted by pH=8, but hindered by the addition of HCO3-, radical scavenger or deoxygenation, while addition of NO3-and NH4+both enhanced the formation of nitrogenous DBPs. Differences in the formation of DBPs in solar photolysis of FAC under various conditions were influenced by reactive species. The formation of trichloromethane (TCM) and haloacetic acids (HAAs) in solar photolysis of FAC positively correlated with the steady-state concentrations of ClO• and O3. The steady-state concentrations of •NO and •NH2 positively correlated with the formation of halonitromethanes (HNMs). HAAs and haloacetonitriles (HANs) mainly contributed to calculated cytotoxicity of DBPs. This study demonstrates that solar photolysis of FAC may significantly impact the formation of DBPs in surface water due to extensive use of disinfectants containing FAC during SARS-CoV-2 pandemic.
Collapse
Affiliation(s)
- Chuze Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Xiating Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Haoran Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Mengting Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Liu Cao
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Yuting Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China
| | - Qiming Xian
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, China.
| |
Collapse
|
16
|
Buckley S, Leresche F, Hanson B, Rosario-Ortiz FL. Decoupling Optical Response and Photochemical Formation of Singlet Oxygen in Size Isolated Fractions of Ozonated Dissolved Organic Matter. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:5603-5610. [PMID: 36977057 DOI: 10.1021/acs.est.2c08155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The complex effects of ozonation on the photophysical and size-based properties of dissolved organic matter (DOM) were investigated using two DOM isolates, Suwannee River Fulvic Acid (SRFA) and Pony Lake Fulvic Acid (PLFA). A size exclusion chromatography system paired with absorbance, fluorescence, and total organic carbon detection was used to determine the fluorescence quantum yield (Φf) as a function of the apparent molecular weight (AMW). Size-based fractions of each isolate were collected and irradiated to measure singlet oxygen (1O2) quantum yield (Φ1O2). Φf decreased with ozonation in low AMW fractions, while increasing in high AMW fractions. Φ1O2 increased with ozone dose in low AMW fractions from ∼2 to ∼7% and ∼3 to ∼11% for PLFA and SRFA, respectively, indicating that these are the most photoreactive fractions of DOM. Decreases in Φf and concomitant increases in Φ1O2 in low AMW fractions indicated that chemical transformations occurred, likely including the conversion of phenols to quinones, particularly in SRFA. Results further suggest that the photoactive and fluorescent fractions of DOM are likely independent pools of chromophores from different AMW fractions. In PLFA, a linear response in Φ1O2, specific UV absorbance at wavelength 254 nm (SUVA254), and Φf with ozonation indicated the equal distribution of ozone-reactive moieties.
Collapse
Affiliation(s)
- Shelby Buckley
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Frank Leresche
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Blair Hanson
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Fernando L Rosario-Ortiz
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, Boulder, Colorado 80309, United States
- Environmental Engineering Program, University of Colorado Boulder, Boulder, Colorado 80309, United States
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
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.
Collapse
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.
| |
Collapse
|
19
|
Sato Y, Xiang Y, Cooper P, Cassol GS, Luo Y, Zeng Q, Shang C, Ren ZJ, Chen G. Evaluating UV 254 absorbance reductions in landfill leachate for municipal sewage co-treatment through timed UV/electrooxidation. JOURNAL OF HAZARDOUS MATERIALS 2023; 445:130624. [PMID: 37056023 DOI: 10.1016/j.jhazmat.2022.130624] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/25/2022] [Accepted: 12/16/2022] [Indexed: 06/19/2023]
Abstract
Landfill leachate contains dissolved organic matter (DOM) exhibiting high ultraviolet absorbance at 254 nm (UVA254). The UVA254 limits leachate co-treatment with municipal sewage by hindering the downstream UV disinfection efficiency at wastewater treatment plants. Here, we alleviated the UVA254 by timing the radiation in a UV/electrooxidation (UV/EO) process to accelerate reactive species formation. At 200 A·m-2, the UV radiation was delayed by 10 min to accumulate 21 mg·L-1 as Cl2, which enhanced the initial radical formation rate by 5.25 times compared with a simultaneous UV/EO. The timed operation increased the steady-state concentrations of ClO• by 700 times to 4.11 × 10-14 M and reduced the leachate UVA254 by 78.2% after 60 min. We identified that aromatic formulas with low oxygen content were susceptible to UV/EO from Fourier-transform ion cyclotron resonance mass spectrometry analysis. The toxicity of the treated leachate and generated byproducts was assessed through specific oxygen uptake rates (SOUR) and developmental assays with Platynereis dumerilii. After quenching the residual chlorine, leachate co-treatment at 3.5% v/v presented minimal toxicological risk. Our findings provide operational insights for applying UV/EO in high UVA254 matrices such as landfill leachate.
Collapse
Affiliation(s)
- Yugo Sato
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yingying Xiang
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Patrick Cooper
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Gabriela Scheibel Cassol
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yu Luo
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Qian Zeng
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Chii Shang
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Zhiyong Jason Ren
- Department of Civil and Environmental Engineering and the Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ 08544, USA
| | - Guanghao Chen
- Department of Civil and Environmental Engineering, Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution (Hong Kong Branch) and Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Fok Ying Tung Research Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
| |
Collapse
|
20
|
Li J, Zhang Z, Xiang Y, Jiang J, Yin R. Role of UV-based advanced oxidation processes on NOM alteration and DBP formation in drinking water treatment: A state-of-the-art review. CHEMOSPHERE 2023; 311:136870. [PMID: 36252895 DOI: 10.1016/j.chemosphere.2022.136870] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Oxidative treatment of drinking water has been practiced for more than a century. UV-based advanced oxidation processes (UV-AOPs) have emerged as promising oxidative treatment technologies to eliminate recalcitrant chemicals and biological contaminants in drinking water. UV-AOPs inevitably alter the properties of natural organic matter (NOM) and affect the disinfection byproduct (DBP) formation in the post-disinfection. This paper provides a state-of-the-art review on the effects of UV-AOPs on the changes of NOM properties and the consequent impacts on DBP formation in the post-chlorination process. A tutorial review to the connotations of NOM properties (e.g., bulk properties, fractional constituents, and molecular structures) and the associated state-of-the-art analytical methods are firstly presented. The impacts of different radical-based AOPs on the changes of NOM properties together with the underlying NOM-radical reaction mechanisms are discussed. The impacts of alteration of NOM properties on DBP formation in the post-chlorination process are then reviewed. The current knowledge gaps and future research needs are finally presented, with emphases on the needs to strengthen the comparability of research data in literature, the accuracy in quantifying the reactive moieties of NOM, and the awareness of unknown DBPs in oxidative water treatment processes. The review and discussion improve the fundamental understanding of NOM-radical and NOM-chlorine chemistry. They also provide useful implications on the engineering design and operation of next-generation drinking water treatment plants.
Collapse
Affiliation(s)
- Juan Li
- Advanced Interdisciplinary Institute of Environment and Ecology, Beijing Normal University, Zhu Hai 519087, PR China; Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999066, Hong Kong, PR China.
| | - Zhong Zhang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Yingying Xiang
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999066, Hong Kong, PR China
| | - Jin Jiang
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, PR China
| | - Ran Yin
- Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999066, Hong Kong, PR China.
| |
Collapse
|
21
|
Wei S, Zhou C, Zhang G, Zheng H, Chen Z, Zhang S. Effects of a redox-active diketone on the photochemical transformation of roxarsone: Mechanisms and environmental implications. CHEMOSPHERE 2022; 308:136326. [PMID: 36084835 DOI: 10.1016/j.chemosphere.2022.136326] [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: 07/13/2022] [Revised: 08/30/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
Organoarsenical antibiotics pose a severe threat to the environment and human health. In aquatic environment, dissolved organic matter (DOM)-mediated photochemical transformation is one of the main processes in the fate of organoarsenics. Dicarbonyl is a typical redox-active moiety in DOM. However, the knowledge on the photoconversion of organoarsenics by DOM, especially the contributions of dicarbonyl moieties is still limited. Here, we systematically investigated the photochemical transformation of three organoarsenics with the simplest β-diketone, acetylacetone (AcAc), as a model dicarbonyl moiety of DOM. The presence of AcAc significantly enhanced the photochemical conversion of roxarsone (ROX), whereas only minor effects were observed for 3-amino-4-hydroxyphenylarsonic acid (HAPA) and arsanilic acid (ASA), because the latter two (with an amino (-NH2) group) are more photoactive than ROX (with a nitro (-NO2) group). The results demonstrate that AcAc was a potent photo-activator and the reduction of -NO2 to -NH2 might be a rate-limiting step in the phototransformation of ROX. At a 1:1 M ratio of AcAc to ROX, the photochemical transformation rate of ROX was increased by 7 folds. In O2-rich environment, singlet oxygen, peroxide radicals, and ·OH were the main reactive species that led to the breakage of the C-As bond in ROX and the oxidation of the released arsono group to arsenate, whereas the triplet-excited state of AcAc (3AcAc*) and carbon-centered radicals from the photolysis of AcAc dominated in the reductive transformation of ROX. In anoxic environment, 3-amino-4-hydroxyphenylarsonic acid was one of the main reductive transformation intermediates of ROX, whose photolysis rate was about 35 times that of ROX. The knowledge obtained here is of great significance to better understand the fate of organoarsenics in natural environment.
Collapse
Affiliation(s)
- Shuangshuang Wei
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Chang Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Hongcen Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Zhihao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
| |
Collapse
|
22
|
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: 14] [Impact Index Per Article: 7.0] [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.
Collapse
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.
| |
Collapse
|
23
|
Li M, Chen N, Shang H, Ling C, Wei K, Zhao S, Zhou B, Jia F, Ai Z, Zhang L. An Electrochemical Strategy for Simultaneous Heavy Metal Complexes Wastewater Treatment and Resource Recovery. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10945-10953. [PMID: 35830297 DOI: 10.1021/acs.est.2c02363] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Heavy metals chelated with coexisting organic ligands in wastewater impose severe risks to public health and the ambient ecosystem but are also valuable metal resources. For sustainable development goals, the treatment of heavy metal complexes wastewater requires simultaneous metal-organic bond destruction and metal resource recovery. In this study, we demonstrated that a neutral pH electro-Fenton (EF) system, which was composed of an iron anode, carbon cloth cathode, and sodium tetrapolyphosphate electrolyte (Na6TPP), could induce a successive single-electron activation pathway of molecular oxygen due to the formation of Fe(II)-TPP complexes. The boosted •OH generation in the Na6TPP-EF process could decomplex 99.9% of copper ethylene diamine tetraacetate within 8 h; meanwhile, the released Cu ions were in situ deposited on the carbon cloth cathode in the form of Cu nanoparticles with a high energy efficiency of 2.45 g kWh-1. Impressively, the recovered Cu nanoparticles were of purity over 95.0%. More importantly, this neutral EF strategy could realize the simultaneous removal of Cu, Ni, and Cr complexes from real electroplating effluents. This study provides a promising neutral EF system for simultaneous heavy metal complexes wastewater treatment and resource recovery and sheds light on the importance of molecular oxygen activation in the field of pollutant control.
Collapse
Affiliation(s)
- Meiqi Li
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Na Chen
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Huan Shang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Cancan Ling
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Kai Wei
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Shengxi Zhao
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Biao Zhou
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Falong Jia
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Zhihui Ai
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Lizhi Zhang
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| |
Collapse
|
24
|
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: 1] [Impact Index Per Article: 0.5] [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.
Collapse
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.
| |
Collapse
|
25
|
Cheng Y, Zhao HQ, Ding A, Chen F, Liu J, Fang D, Li C, Huang Y, Lu P. Singlet oxygen-dominated electrocatalytic oxidation treatment for the high-salinity quaternary ammonium compound wastewater with Ti/(Ru xIr y)O 2 anode. ENVIRONMENTAL RESEARCH 2022; 209:112815. [PMID: 35093311 DOI: 10.1016/j.envres.2022.112815] [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: 12/11/2021] [Revised: 01/17/2022] [Accepted: 01/22/2022] [Indexed: 06/14/2023]
Abstract
The widespread application of quaternary ammonium compounds (QAC) has posed a serious hazard to the environment and human being, and high concentration of Cl- in QAC wastewater may further increase the difficulty of pollutants elimination. In this study, such a QAC wastewater under high salinity conditions was chosen as the target, the prepared Ti/(RuxIry)O2 anode exhibited favorable catalytic performance for the oxidation and mineralization of QAC under high salinity conditions. Increasing the Ru/Ir ratio of Ti-based electrode coating also slightly promoted the inner catalytic capacity. The combination of electron paramagnetic resonance (EPR) and quenching experiments indicates that 1O2 served as a main reactive specie in the Ti/(RuxIry)O2 electrooxidation system. The increase of pH could decrease the removal efficiency of QAC for the reduced 1O2 yield, and the rise of Cl- concentration could favor the QAC oxidation, and Cl- was a better electrolyte to promote the oxidation of organic contaminants when compared to Na2SO4 or Na2CO3. Additionally, the conversion pathway of the model pollutant was tentatively investigated, the results demonstrated that there were almost no halogenated final products residual by electrocatalytic oxidation with Ti/(RuxIry)O2 anode. This study not only elucidate the reaction mechanism of Ti/(RuxIry)O2 anode electrocatalytic oxidation of high salinity QAC wastewater, but also may provide an efficacious and eco-friendly method for the treatment of high salinity QAC wastewater.
Collapse
Affiliation(s)
- Yong Cheng
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China; Key Laboratory of Three Gorges Reservoir Region 's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Han-Qing Zhao
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China; Key Laboratory of Three Gorges Reservoir Region 's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China.
| | - Aqiang Ding
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China; Key Laboratory of Three Gorges Reservoir Region 's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Fei Chen
- Key Laboratory of Three Gorges Reservoir Region 's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Jun Liu
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China; Key Laboratory of Three Gorges Reservoir Region 's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
| | - Dazhi Fang
- Sinopec Chongqing Shale Gas Co., Ltd, Chongqing, 408400, China
| | - Chenglong Li
- Sinopec Chongqing Shale Gas Co., Ltd, Chongqing, 408400, China
| | - Yongkui Huang
- National and Local Joint Engineering Research Center of Shale Gas Exploration and Development, Key Laboratory of Shale Gas Exploration, Ministry of Natural Resources, Chongqing Institute of Geology and Mineral Resources, Chongqing, 401120, China
| | - Peili Lu
- State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China; Key Laboratory of Three Gorges Reservoir Region 's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, China.
| |
Collapse
|
26
|
Xiao X, Powers LC, Liu J, Gonsior M, Zhang R, Zhang L, MacIntyre HL, Chen X, Hu C, Batt J, Shi Q, Xu D, Zhang Y, Jiao N. Biodegradation of Terrigenous Organic Matter in a Stratified Large-Volume Water Column: Implications of the Removal of Terrigenous Organic Matter in the Coastal Ocean. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:5234-5246. [PMID: 35357815 DOI: 10.1021/acs.est.1c08317] [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] [Indexed: 06/14/2023]
Abstract
Large amounts of terrigenous organic matter (TOM) are delivered to the ocean every year. However, removal processes of TOM in the ocean are still poorly constrained. Here, we report results from a 339-day dark incubation experiment with a unique system holding a vertically stratified freshwater-seawater column. The quality and quantity of dissolved organic matter (DOM), RNA-based size-fraction microbial communities, and environmental factors were high-frequency-monitored. Microbial processes impacted TOM composition, including an increased DOM photobleaching rate with incubation time. The mixed layer had changed the bacterial community structure, diversity, and higher oxygen consumption rate. A two-end member modeling analysis suggested that estimated nutrient concentrations and prokaryotic abundance were lower, and total dissolved organic carbon was higher than that of the measured values. These results imply that DOM biodegradation was stimulated during freshwater-seawater mixing. In the bottom layer, fluorescent DOM components increased with the incubation time and were significantly positively related to highly unsaturated, oxygenated, and presumably aromatic compound molecular formulas. These results suggest that surfaced-derived TOM sinking leads to increased DOM transformation and likely results in carbon storage in the bottom water. Overall, these results suggest that microbial transforming TOM plays more important biogeochemical roles in estuaries and coastal oceans than what we know before.
Collapse
Affiliation(s)
- Xilin Xiao
- College of the Environment and Ecology, Xiamen University, Xiamen361102, China
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Leanne C Powers
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, Maryland20688, United States
| | - Jihua Liu
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
- Institute of Marine Science and Technology, Shandong University, Qingdao266237, China
| | - Michael Gonsior
- Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, Maryland20688, United States
| | - Rui Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Lianbao Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Hugh L MacIntyre
- Department of Oceanography, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Xiaowei Chen
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Chen Hu
- College of the Environment and Ecology, Xiamen University, Xiamen361102, China
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - John Batt
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
- Department of Oceanography, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Qiang Shi
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
- Department of Oceanography, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Dapeng Xu
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Yao Zhang
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| | - Nianzhi Jiao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiamen361102, China
- Joint Laboratory for Ocean Research and Education (LORE) of Dalhousie University, Canada, and Shandong University and Xiamen University, Xiamen361102, China
| |
Collapse
|
27
|
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.
Collapse
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.
| |
Collapse
|
28
|
Zhang S, Lan H, Cui Y, An X, Liu H, Qu J. Insight into the Key Role of Cr Intermediates in the Efficient and Simultaneous Degradation of Organic Contaminants and Cr(VI) Reduction via g-C 3N 4-Assisted Photocatalysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:3552-3563. [PMID: 35212521 DOI: 10.1021/acs.est.1c08440] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Photocatalysis provides an impetus for the synergetic removal of Cr(VI) and organic contaminants, but the generation of Cr intermediates and their potential oxidizability may be overlooked in pollutant conversion. Herein, the Cr intermediates in the Cr(VI) reduction process were emphasized in Cr(VI)/bisphenol A (BPA) by using graphitic carbon nitride as a photocatalyst. The active species for BPA photodegradation in the BPA system and Cr(VI)/BPA system suggested that the Cr(VI) reduction process indeed promotes BPA photodegradation. Electron paramagnetic resonance (EPR) of Cr complexes and in situ variable-temperature EPR analysis demonstrated Cr(V) intermediate (g = 1.978) generation in Cr(VI) reduction and its oxidization for BPA degradation in photocatalysis. By adding the electron donor Na2SO3, BPA degradation was induced in Cr(VI)/BPA solution, further confirming the positive effect of Cr(V). Moreover, the difference in BPA degradation products in the BPA/air, Cr(VI)/BPA/air, and Cr(VI)/BPA/Ar systems indirectly explained why the Cr(V) intermediate was involved in BPA degradation. Density functional theory calculations revealed that photogenerated electrons can reduce the free energy (0.98 eV) of converting Cr(VI) into Cr(V), which can facilitate the subsequent Cr(V) oxidation step for BPA degradation. This work contributes to the exploration of the Cr(VI) reduction process and the synergistic removal of organic pollutants in Cr(VI)/organics systems.
Collapse
Affiliation(s)
- Shun Zhang
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Huachun Lan
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Yuqi Cui
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Xiaoqiang An
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Huijuan Liu
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jiuhui Qu
- Center for Water and Ecology, State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| |
Collapse
|
29
|
Guo K, Wu Z, Chen C, Fang J. UV/Chlorine Process: An Efficient Advanced Oxidation Process with Multiple Radicals and Functions in Water Treatment. Acc Chem Res 2022; 55:286-297. [PMID: 35025201 DOI: 10.1021/acs.accounts.1c00269] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Because of the deterioration of global water quality, the occurrence of chemical and microbial contaminants in water raises serious concerns for the health of the population. Identifying and developing effective and environmentally friendly water treatment technologies are critical to obtain clean water. Among the various technologies for the purification of water, ultraviolet photolysis of chlorine (UV/chlorine), an emerging advanced oxidation process (AOP), has multiple functions for the control of contaminants via the production of hydroxyl radicals (HO·) and reactive chlorine species (RCS), such as Cl·, ClO·, and Cl2·-.This Account centers around the radical chemistry of RCS and HO· in different water matrices and their roles and mechanisms in the abatement of contaminants. The concentrations of Cl·, ClO·, and Cl2·- are comparable to or higher than those of HO· (10-14 to 10-13 M). The reactivities of RCS are more selective than HO· with a broader range of second-order rate constants (k). The k values of Cl· toward most aromatics are higher or similar as compared to those of HO·, while those of Cl2·- and ClO· are less reactive but more selective toward aromatics containing electron-donating functional groups. Their major reaction mechanisms with Cl· are electron transfer and addition, while those with ClO· and Cl2·- primarily involve electron transfer. As for aliphatics, their reactivities with both HO· and RCS are much lower than those of aromatics. The reaction mechanisms for most of them with Cl· and Cl2·- are hydrogen abstraction, except for olefins, which are addition. In addition, RCS greatly contribute to the inactivation of microbial contaminants.Toward future application, the UV/chlorine process has both pros and cons. Compared with the traditional HO·-based AOP of UV/H2O2, UV/chlorine is more efficient and energy-saving for oxidation and disinfection, and its efficiency is less affected by water matrix components. However, the formation of toxic byproducts in UV/chlorine limits its application scenarios. In dissolved organic matter (DOM)-rich water, the formation of halogenated byproducts is enhanced in UV/chlorine. In the presence of ammonia, reactive nitrogen species (RNS) (e.g., ·NO and ·NO2) are involved, and highly toxic nitro(so) products such as nitro(so)-phenolics and N-nitrosodimethylamine are generated. For a niche application, the UV/chlorine process is recommended to be utilized in water with low levels of DOM and ammonia.Strategies should be developed to make full use of highly reactive species (RCS and HO·) for the abatement of target contaminants and to reduce the formation of toxic byproducts. For example, the UV/chlorine process can be used in tandem with other treatments to create multiple barriers for the production of safe water. In addition, halogen radicals are very important in ecosystems as well as other areas such as medical therapy and organic synthesis. UV/chlorine is the most efficient homogeneous system to generate halogen radicals, and thus it provides a perfect system to investigate the fates of halogen radicals for interdisciplinary research.
Collapse
Affiliation(s)
- Kaiheng Guo
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
| | - Zihao Wu
- Advanced Institute of Natural Sciences, Beijing Normal University at Zhuhai Zhuhai 519087, P. R. China
| | - Chunyan Chen
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
| | - Jingyun Fang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, P. R. China
| |
Collapse
|