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Ao X, Zhang X, Sun W, Linden KG, Payne EM, Mao T, Li Z. What is the role of nitrate/nitrite in trace organic contaminants degradation and transformation during UV-based advanced oxidation processes? WATER RESEARCH 2024; 253:121259. [PMID: 38377923 DOI: 10.1016/j.watres.2024.121259] [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: 12/27/2023] [Revised: 02/01/2024] [Accepted: 02/03/2024] [Indexed: 02/22/2024]
Abstract
The effectiveness of UV-based advanced oxidation processes (UV-AOPs) in degrading trace organic contaminants (TrOCs) can be significantly influenced by the ubiquitous presence of nitrate (NO3-) and nitrite (NO2-) in water and wastewater. Indeed, NO3-/NO2- can play multiple roles of NO3-/NO2- in UV-AOPs, leading to complexities and conflicting results observed in existing research. They can inhibit the degradation of TrOCs by scavenging reactive species and/or competitively absorbing UV light. Conversely, they can also enhance the elimination of TrOCs by generating additional •OH and reactive nitrogen species (RNS). Furthermore, the presence of NO3-/NO2- during UV-AOP treatment can affect the transformation pathways of TrOCs, potentially resulting in the nitration/nitrosation of TrOCs. The resulting nitro(so)-products are generally more toxic than the parent TrOCs and may become precursors of nitrogenous disinfection byproducts (N-DBPs) upon chlorination. Particularly, since the impact of NO3-/NO2- in UV-AOPs is largely due to the generation of RNS from NO3-/NO2- including NO•, NO2•, and peroxynitrite (ONOO-/ONOOH), this review covers the generation, properties, and detection methods of these RNS. From kinetic, mechanistic, and toxicologic perspectives, future research needs are proposed to advance the understanding of how NO3-/NO2- can be exploited to improve the performance of UV-AOPs treating TrOCs. This critical review provides a comprehensive framework outlining the multifaceted impact of NO3-/NO2- in UV-AOPs, contributing insights for basic research and practical applications of UV-AOPs containing NO3-/NO2-.
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Affiliation(s)
- Xiuwei Ao
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, International Science and Technology Cooperation Base for Environmental and Energy Technology of MOST, University of Science and Technology Beijing, Beijing, 100083, China
| | - Xi Zhang
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, International Science and Technology Cooperation Base for Environmental and Energy Technology of MOST, University of Science and Technology Beijing, Beijing, 100083, China
| | - Wenjun Sun
- School of Environment, Tsinghua University, Beijing 100084, China; Research Institute for Environmental Innovation (Suzhou) Tsinghua, Suzhou, 215163, China.
| | - Karl G Linden
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, CO 80303, United States.
| | - Emma M Payne
- Department of Civil, Environmental, and Architectural Engineering, University of Colorado Boulder, 4001 Discovery Drive, Boulder, CO 80303, United States
| | - Ted Mao
- Research Institute for Environmental Innovation (Suzhou) Tsinghua, Suzhou, 215163, China; MW Technologies, Inc., Ontario L8N1E, Canada
| | - Zifu Li
- School of Energy and Environmental Engineering, Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, International Science and Technology Cooperation Base for Environmental and Energy Technology of MOST, University of Science and Technology Beijing, Beijing, 100083, China
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Tang L, Li A, Kong M, Dionysiou DD, Duan X. Effects of wavelength on the treatment of contaminants of emerging concern by UV-assisted homogeneous advanced oxidation/reduction processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:165625. [PMID: 37481088 DOI: 10.1016/j.scitotenv.2023.165625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/09/2023] [Accepted: 07/16/2023] [Indexed: 07/24/2023]
Abstract
Pollutants of emerging concern in aqueous environments present a significant threat to both the aquatic ecosystem and human health due to their rapid transfer. Among the various treatment approaches to remove those pollutants, UV-assisted advanced oxidation/reduction processes are considered competent and cost-effective. The treatment effectiveness is highly dependent on the wavelength of the UV irradiation used. This article systematically discusses the wavelength dependency of direct photolysis, UV/peroxides, UV/chlor(am)ine, UV/ClO2, UV/natural organic matter, UV/nitrate, and UV/sulfite on the transformation of contaminants. Altering wavelengths affects the photolysis of target pollutants, photo-decay of the oxidant/reductant, and quantum yields of reactive species generated in the processes, which significantly impact the degradation rates and formation of disinfection byproducts. In general, the degradation of contaminants is most efficient when using wavelengths that closely match the highest molar absorption coefficients of the target pollutants or the oxidizing/reducing agents, and the contribution of pollutant absorption is generally more significant. By matching the wavelength with the peak absorbance of target compounds and oxidants/reductants, researchers and engineers have the potential to optimize the UV wavelengths used in UV-AO/RPs to effectively remove pollutants and control the formation of disinfection byproducts.
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Affiliation(s)
- Liang Tang
- Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Aozhou Li
- Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
| | - Minghao Kong
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA.
| | - Xiaodi Duan
- Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
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Chai Z, Wang J, Dai Y, Du E, Guo H. Synergy between UV light and trichloroisocyanuric acid on methylisothiazolinone degradation: Performance, kinetics and degradation pathway. ENVIRONMENTAL RESEARCH 2023; 236:116693. [PMID: 37481058 DOI: 10.1016/j.envres.2023.116693] [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: 05/23/2023] [Revised: 06/26/2023] [Accepted: 07/16/2023] [Indexed: 07/24/2023]
Abstract
Methylisothiazolinone (MIT) is widely used in daily chemicals, fungicides, and other fields and its toxicity has posed a threat to water system and human health. In this study, ultraviolet (UV)/trichloroisocyanuric acid (TCCA), which belongs to advanced oxidation processes (AOP), was adopted to degrade MIT. Total chlorine attenuation detection proved that TCCA has medium UV absorption and a strong quantum yield (0.49 mol E-1). At a pH of 7.0, 93.5% of MIT had been decontaminated after 60 min in UV/TCCA system (kobs = 4.4 × 10-2 min-1, R2 = 0.978), which was much higher than that in the UV alone system and TCCA alone system, at 65% (1.7 × 10-2 min-1, R2 = 0.995) and 10% (1.8 × 10-3 s-1, R2 = 0.915), respectively. This system also behaved well in degrading other five kinds of contaminants. Tert-butanol (TBA) and carbonate (CO32-) were separately used in quenching experiments, and the degradation efficiency of MIT decreased by 39.5% and 46.5% respectively, which confirmed that HO• and reactive chlorine species (RCS) were dominant oxidants in UV/TCCA system. With TCCA dosage increasing in a relatively low concentration range (0.02-0.2 mM) and pH decreasing, the effectiveness of this AOP system would be strengthened. The influences of coexisting substances (Cl-, SO42-, CO32-, NO2- and NO3-) were explored. MIT degradation pathways were proposed and sulfur atom oxidation and carboxylation were considered as the dominant removal mechanisms of MIT. Frontier orbital theory and Fukui indexes of MIT were employed to further explore the degradation mechanism.
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Affiliation(s)
- Zhizhuo Chai
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
| | - Jingquan Wang
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
| | - Yixue Dai
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
| | - Erdeng Du
- School of Environmental and Safety Engineering, Changzhou University, Changzhou, 213164, China.
| | - Hongguang Guo
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
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Yuan Y, Feng L, He X, Wu M, Ai Z, Zhang L, Gong J. Nitrate promoted defluorination of perfluorooctanoic acid in UV/sulfite system: Coupling hydrated electron/reactive nitrogen species-mediated reduction and oxidation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 313:120172. [PMID: 36115490 DOI: 10.1016/j.envpol.2022.120172] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 08/28/2022] [Accepted: 09/09/2022] [Indexed: 06/15/2023]
Abstract
A significantly accelerated defluorination of recalcitrant perfluorooctanoic acid (PFOA) was explored with the co-present nitrate (20 mg L-1) by UV/sulfite treatment (UV/sulfite-nitrate). The deep defluorination of PFOA and complete denitrification of nitrate were simultaneously achieved in UV/sulfite-nitrate system. At the initial 30 min, PFOA defluorination exhibited an induction period, exactly corresponding to the removal of the co-existed nitrate. Upon the induction period passed, an accelerated removal of PFOA (5 mg L-1) occurred, nearly 100% defluorination ratio reached within 2 h. Compared with those in UV/sulfite, the kinetics of PFOA decay, defluorination, and transformation product formations were greatly enhanced in UV/sulfite-nitrate system. Reactive nitrogen species (RNS) generated from eaq--induced reduction of nitrate were found to play significant roles on the promoted defluorination apart from eaq--mediated reductive defluorination. The investigations on solution pH (7.0-11.0) confirmed that the reductive defluorination of PFOA was more efficient under alkaline conditions, however, the presence of nitrate can promote the defluorination even under neutral pH. Theoretical calculations of Fukui function demonstrated that RNS could easily launch electrophilic attack toward H-rich moieties of fluorotelomer carboxylates (FTCAs, CnF2n+1-(CH2)m-COO-), more persistent intermediates (formed via H/F exchange), and convert FTCAs into shorter-chain perfluorinated carboxylic acids, thus facilitating the deep defluorination. Along with the analysis on the denitrification products, the liberation of fluoride ions and generated intermediates, possible decomposition pathways were proposed. This work highlights the indispensable synergy from eaq-/RNS with integrated reduction and oxidation on PFOA defluorination and will advance remediation technologies of perfluorinated compound contaminated water.
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Affiliation(s)
- Yijin Yuan
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Lizhen Feng
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Xianqin He
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China
| | - Mengsi Wu
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR 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, PR 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, PR China
| | - Jingming Gong
- Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan, 430079, PR China.
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5
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Song Z, Li J, Xu H, Li Y, Zeng Y, Guan B. Heterogeneous catalytic ozonation by amorphous boron for degradation of atrazine in water. CHINESE CHEM LETT 2022. [DOI: 10.1016/j.cclet.2022.107876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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6
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Liu X, Chang F, Zhang D, Ren M. Influence of nitrate/nitrite on the degradation and transformation of triclosan in the UV based disinfection. CHEMOSPHERE 2022; 298:134258. [PMID: 35271891 DOI: 10.1016/j.chemosphere.2022.134258] [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] [Received: 01/13/2022] [Revised: 02/11/2022] [Accepted: 03/06/2022] [Indexed: 06/14/2023]
Abstract
This study investigated the influence of nitrate/nitrite on the degradation and transformation pathway of triclosan (TCS) in UV, UV/peracetic acid (PAA) and UV/HClO processes. The results indicated that the function of nitrate/nitrite significantly depended on the UV source and wavelength, especially nitrate. Generally, the presence of nitrate decreased the direct photo-degradation of TCS in the UV based disinfection. In the LED-UV and LED-UV/HClO processes, the presence of nitrate improved the radical oxidation, and transformation pathway of TCS was varied accordingly. However, nitrate more played a role of photo-competitor in the UV/PAA process, and the reactive nitrogen species (RNS) was difficult to participant in the degradation of TCS due to low redox potential. Compared to nitrate, the presence of nitrite decreased the degradation of TCS in three different UV based disinfection processes. Under UV irradiation, nitrite primarily acted as an irradiation competitor and radical scavenger. Thus, the indirect photo-degradation of TCS was reduced. Noticeably, nitrate/nitrite were the improtant precersors of nitrogenous products in the UV base disinfection. Many new nitrogenous products were identified. But RNS preferentially reacted with the intermediates by -NO2 addition compared to directly reacted with TCS.
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Affiliation(s)
- Xuguang Liu
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, China; Institute of International Rivers and Eco-security, Yunnan University, Kunming, 650091, China
| | - Fengqin Chang
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, China.
| | - Dayu Zhang
- School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, China
| | - Meijie Ren
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming, 650091, China.
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7
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Guo J, Deng J, An B, Tian J, Wu J, Liu Y. Selective reduction of nitrate to nitrogen by Fe 0-Cu 0-CuFe 2O 4 composite coupled with carbon dioxide anion radical under UV irradiation. CHEMOSPHERE 2022; 295:133785. [PMID: 35104554 DOI: 10.1016/j.chemosphere.2022.133785] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/13/2022] [Accepted: 01/26/2022] [Indexed: 06/14/2023]
Abstract
Zero-valent iron (Fe0) has been widely used for the reduction of nitrate, but the end reduction product is mainly ammonium. Here, a novel strategy for selective reduction of nitrate (NO3-) to nitrogen gas (N2) with high efficiency and N2 selectivity was investigated using Fe-based material (Fe0-Cu0-CuFe2O4) combined with citric acid (CA) and ultraviolet (UV) irradiation. In this strategy, the nitrate was firstly reduced to nitrite (NO2-) by Fe0-Cu0-CuFe2O4/UV process, and then the produced NO2- could be further reduced to N2 by carbon dioxide anion radicals (CO2•-) which was generated from CA that was added later. In this process, the selective reduction of NO3- to NO2- was a key step. For this purpose, we synthesized Fe0-Cu0-CuFe2O4 composite by simple chemical replacement and in-situ growth process, which made it have a delicate structure with good contact between Cu and Fe and CuFe2O4. The selective reduction of NO3- to NO2- in Fe0-Cu0-CuFe2O4/UV process was due to that the Cu0 was the electron enrichment center and the photo-generated hole could suppress the NO3- reduction to NH4+ by Fe2+. In this proposed strategy, 100% NO3- removal efficiency and 96.3% N2 selectivity were achieved when the initial NO3- concentration was 30 mg N/L and the reduction time was 60 min. The denitrification mechanism of the Fe0-Cu0-CuFe2O4/UV/CA system was proposed.
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Affiliation(s)
- Jinrui Guo
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Jinhua Deng
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Baohua An
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Jing Tian
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Junshu Wu
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China
| | - Yong Liu
- College of Chemistry and Materials Science, Sichuan Normal University, Chengdu, 610066, China; Key Laboratory of Treatment for Special Wastewater of Sichuan Province Higher Education System, Jing'an Road 5, Jinjiang District, Sichuan, Chengdu, 610066, China.
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Sbizzaro M, César Sampaio S, Rinaldo dos Reis R, de Assis Beraldi F, Medina Rosa D, Maria Branco de Freitas Maia C, Saramago de Carvalho Marques dos Santos Cordovil C, Tillvitz do Nascimento C, Antonio da Silva E, Eduardo Borba C. Effect of production temperature in biochar properties from bamboo culm and its influences on atrazine adsorption from aqueous systems. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.117667] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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9
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Gao X, Lu J, Ji Y, Chen J, Yin X, Zhou Q. Nitrite-mediated photodegradation of sulfonamides and formation of nitrated products. CHEMOSPHERE 2021; 282:130968. [PMID: 34111634 DOI: 10.1016/j.chemosphere.2021.130968] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/08/2021] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
In this study, we systematically investigated the indirect photolysis of five SAs, i.e., sulfamethazine (SMZ), sulfamethoxazole (SMX), sulfathiazole (STZ), sulfapyridine (SPD), and sulfamethizole (SMT), under UV-A irradiation (365 nm) and mediated by nitrite (NO2‾) at environmentally relevant concentrations (0.005-0.1 mM). The SAs that are resistant to direct photolysis can be effectively removed in UV/NO2‾ system. SAs with a six-membered heterocyclic ring (i.e., SMZ and SPD) were degraded more quickly than those with a five-membered heterocyclic ring (i.e., SMX, STZ and SMT). The pseudo-first-order rate constants (k) at nitrite concentration of 0.1 mM followed the order of kSPD (0.0265 min-1) > kSMZ (0.0245 min-1) > kSMX (0.0184 min-1) > kSTZ (0.0176 min-1) > kSMT (0.0154 min-1). A kinetic model was developed and the contributions of direct UV photolysis, OH, and RNS to SAs degradation in UV/NO2‾ system were calculated. At NO2‾ concentration of 0.1 mM, the contributions of OH and RNS for SAs removal were 29.17-46.53% and 52.33-63.28%, respectively. Main transformation pathways including hydroxylation and nitration were proposed, based on liquid chromatography mass spectrometry analysis of the degradation products and density functional theory calculation. However, Smile-type rearrangement which generated a SO2-extrusion product was only observed in the degradation of SAs with a six-membered ring, which explains their higher degradation rate than those with a five-membered ring. The presence of natural organic matter (NOM) decreased the formation of nitrated products. Overall, these results will be helpful to understand the fate and the potential ecological risks of SAs in sunlit aquatic environments.
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Affiliation(s)
- Xu Gao
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Junhe Lu
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yuefei Ji
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jing Chen
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Xiaoming Yin
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China
| | - Quansuo Zhou
- Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China
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10
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Photolysis of nitrate by solar light in agricultural runoffs: Degradation of emerging contaminant vs. formation of unintended products. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.118751] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Wang T, Huang T, Jiang H, Ma R. Electrochemical degradation of atrazine by BDD anode: Evidence from compound-specific stable isotope analysis and DFT simulations. CHEMOSPHERE 2021; 273:129754. [PMID: 33524760 DOI: 10.1016/j.chemosphere.2021.129754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Direct charge transfer (DCT) and •OH attack played important roles in contaminant degradation by BDD electrochemical oxidation. Their separate contributions and potential bond-cleavage processes were required but lacking. Here, we carried out promising compound-specific isotope fractionation analysis (CSIA) to explore 13C and 2H isotope fractionation of atrazine (ATZ), followed by assessing the reaction pathway by BDD anode. The correlation of 2H and 13C fractionation allows to remarkably differentiate DCT process and •OH attack, with Λ values of 18.99 and 53.60, respectively. Radical quenching identified that •OH accounted for 79.0%-88.5% in the whole reaction. While CSIA methods provided biased results, which suggested that ATZ degradation exhibited two stages with •OH contributions of 24.6% and 84.3% respectively, confirming CSIA was more sensitive and provided more possibilities to estimate degradation processes. Combined with Fukui index and intermediate products identification, we deduced that dechlorination-hydroxylation mainly occurred in the first 30 min by DCT reaction. While lateral chain oxidation with C-N broken was the governing route once •OH was largely generated, with the production of DEA (m/z 188), DIA (m/z 174), DEIA (m/z 146) and DEIHA (m/z 128). Our results demonstrated that isotope fractionation can offer "isotopic footprints" for identifying the rate-limiting steps and bond breakage process, and opens new avenues for degradation pathways of contaminants.
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Affiliation(s)
- Ting Wang
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China; State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems, Beijing, 100871, China.
| | - Taobo Huang
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
| | - Huan Jiang
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
| | - Ruoqi Ma
- College of Environmental Sciences and Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing, 100871, China
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12
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Degradation of Congo red by UV photolysis of nitrate: Kinetics and degradation mechanism. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2020.118276] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Zhou S, Li L, Wu Y, Zhu S, Zhu N, Bu L, Dionysiou DD. UV 365 induced elimination of contaminants of emerging concern in the presence of residual nitrite: Roles of reactive nitrogen species. WATER RESEARCH 2020; 178:115829. [PMID: 32375111 DOI: 10.1016/j.watres.2020.115829] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/09/2020] [Accepted: 04/11/2020] [Indexed: 06/11/2023]
Abstract
The presence of nitrite (NO2-) is inevitable with concentrations of several mg L-1 in some typical water bodies. In this study, UV at wavelength of 365 nm was investigated to degrade contaminants of emerging concern (CECs) in the presence of NO2- at environmentally relevant concentrations (0.1-5.0 mg L-1). Six selected CECs with different structures were efficiently removed because of the generation of reactive nitrogen species (RNS) and hydroxyl radical (HO•) from photolysis of NO2-. Contributions of UV365 photolysis, RNS, and HO• to CEC degradation in UV365/NO2- system were calculated, and RNS were found to be the predominant species that are responsible for CEC degradation. The second major contributor is HO• for the degradation of selected CECs except for the case of sulfadiazine. Impacts of water matrix components (including dissolved oxygen, solution pH, and natural organic matter) on CEC degradation in UV365/NO2- system were evaluated. Furthermore, evolution profiles of CECs and NO2- in UV365/NO2- system were tracked when actual water samples were used as background, and a simultaneous removal of CECs and NO2- was observed. Transformation products of bisphenol A and carbamazepine were proposed according to the results of HPLC/MS and quantum chemistry calculations. Nitration induced by RNS and hydroxylation induced by HO• are main reactions occurred during CEC degradation in UV365/NO2- system. Overall, UV365 is a potential technology to remove CECs and NO2- in aquatic environment when residual NO2- is present. Our present study also provides possibility for the application of sunlight to remediate water co-polluted by CECs and NO2-.
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Affiliation(s)
- Shiqing Zhou
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China
| | - Ling Li
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China
| | - Yangtao Wu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China
| | - Shumin Zhu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China.
| | - Ningyuan Zhu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, 71 East Beijing Road, Nanjing, 210008, China
| | - Lingjun Bu
- Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China.
| | - Dionysios D Dionysiou
- Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH, 45221-0012, USA
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