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Chen S, Zhao Z, Wang C, Cui F. VUV coupled with low-dose H 2O 2 as pretreatment prior to UF: Performance, mechanisms, DBPs formation and toxicity evaluation. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134966. [PMID: 38901255 DOI: 10.1016/j.jhazmat.2024.134966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 05/17/2024] [Accepted: 06/17/2024] [Indexed: 06/22/2024]
Abstract
Ultrafiltration (UF) is widely used in drinking water plants; however, membrane fouling is unavoidable. Natural organic matter (NOM) is commonly considered as an important pollutant that causes membrane fouling. Herein, we proposed VUV/H2O2 as a UF pretreatment and used UV/H2O2 for comparison. Compared to UV/H2O2, the VUV/H2O2 system presented superior NOM removal. In the VUV/H2O2 system, the steady-state concentration of HO• was approximately twice that in the UV/H2O2 system, which was ascribed to the promoting effect of the 185 nm photons. Specifically, 185 nm photons promoted HO• generation by decomposing mainly H2O at a low H2O2 dose or by decomposing mainly H2O2 at a high H2O2 dose. The VUV/H2O2 pretreatment also demonstrated better membrane fouling mitigation performance than did UV/H2O2. An increase in the H2O2 dose promoted HO• generation, thereby enhancing the performance of NOM degradation and membrane fouling alleviation and shifting the major membrane fouling mechanism from cake filtration to standard blocking. The VUV/H2O2 (0.60 mM) pretreatment effectively reduced disinfection byproducts (DBPs) formation during chlorine disinfection. Additionally, the oxidant H2O2 affected the membrane surface morphology and performance but had no evident effect on the mechanical properties. In actual water treatment, the VUV/H2O2 pretreatment exhibited better performance than the UV/H2O2 pretreatment in easing membrane fouling, ameliorating water quality, and reducing DBPs formation and acute toxicity.
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Affiliation(s)
- Shengnan Chen
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
| | - Zhiwei Zhao
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China; School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, PR China.
| | - Chuang Wang
- School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, Hunan 411201, PR China
| | - Fuyi Cui
- College of Environment and Ecology, Chongqing University, Chongqing 400045, PR China
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Zhang H, Sun W, Zhang J, Ma J. Vacuum-ultraviolet based advanced oxidation and reduction processes for water treatment. JOURNAL OF HAZARDOUS MATERIALS 2024; 471:134432. [PMID: 38691932 DOI: 10.1016/j.jhazmat.2024.134432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 04/02/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
The use of vacuum-ultraviolet (VUV) photolysis in water treatment has been gaining significant interest due to its efficacy in degrading refractory organic contaminants and eliminating oxyanions. In recent years, the reactive species driving pollutant decomposition in VUV-based advanced oxidation and reduction processes (VUV-AOPs and VUV-ARPs) have been identified. This review aims to provide a concise overview of VUV photolysis and its advancements in water treatment. We begin with an introduction to VUV irradiation, followed by a summary of the primary reactive species in both VUV-AOPs and VUV-ARPs. We then explore the factors influencing VUV-photolysis in water treatment, including VUV irradiation dose, catalysts or activators, dissolved gases, water matrix components (e.g., DOM and inorganic anions), and solution pH. In VUV-AOPs, the predominant reactive species are hydroxyl radicals (˙OH), hydrogen peroxide (H2O2), and ozone (O3). Conversely, in VUV-ARPs, the main reactive species are the hydrated electron (eaq-) and hydrogen atom (˙H). It is worth noting that VUV-based advanced oxidation/reduction processes (VUV-AORPs) can transit between VUV-AOPs and VUV-ARPs based on the externally added chemicals and dissolved gases in the solution. Increase of the VUV irradiation dose and the concentration of catalysts/activators enhances the degradation of contaminants, whereas DOM and inorganic anions inhibit the reaction. The pH influences the redox potential of ˙OH, the speciation of contaminants and activators, and thus the overall performance of the VUV-AOPs. Conversely, an alkaline pH is favored in VUV-ARPs because eaq- predominates at higher pH.
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Affiliation(s)
- Honglong Zhang
- School of Environment, Harbin Institute of Technology, Harbin 150090, PR China; Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, PR China
| | - Wenjun Sun
- School of Environment, Tsinghua University, Beijing 100084, PR China
| | - Jing Zhang
- School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
| | - Jun Ma
- School of Environment, Harbin Institute of Technology, Harbin 150090, PR China
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Pan H, Chen B. How I - alters UV and UV/VUV processes' redox capacities: Evidences from iodine species evolution, hydrogen peroxide formation, and oxyhalides degradation? JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133457. [PMID: 38219580 DOI: 10.1016/j.jhazmat.2024.133457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 01/16/2024]
Abstract
Although UV and/or VUV tandem I- are often proposed as advanced reduction processes (ARPs) to eliminate micropollutants by generating eaq-, the fate of I- and its byproducts formation remain to be explored. Therefore, this study investigated the iodine species evolution during UV/I- and UV/VUV/I- processes under different influencing factors. Results show that UV/VUV oxidized most of I- to IO3- whereas UV only oxidized a portion of I- to intermediate reactive iodine species (RISs, including I2, HOI, and I3-); meanwhile, substantial H2O2 was generated only in UV/VUV/I- process but not in UV/I- process, proving that UV/VUV owns stronger oxidation ability than UV alone. Spiking I- into water exerted triple-sided effects by consuming •OH, generating eaq-, and shielding light, thus complicating the systems. Holistically, increasing pH or decreasing dissolved oxygen converted oxidizing environment into reducing condition and caused less RISs formation, especially for UV/VUV/I-. For oxyhalides, neither UV/I- nor UV/VUV/I- degraded ClO4-. While UV/I- cannot remove ClO3-, UV/VUV/I- reduced ClO3- to Cl-. Expectedly, both UV/I- and UV/VUV/I- reduced BrO3- to Br- more efficiently than UV and UV/VUV, confirming that I- can enhance the reduction capacities of UV/VUV and UV technologies.
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Affiliation(s)
- Huimei Pan
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Baiyang Chen
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
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Liu W, Chen B, Yang Y, Li B, Pan H, Luo W. Photo-anammox by vacuum ultraviolet tandem chlorine. JOURNAL OF HAZARDOUS MATERIALS 2024; 463:132876. [PMID: 37944232 DOI: 10.1016/j.jhazmat.2023.132876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/15/2023] [Accepted: 10/25/2023] [Indexed: 11/12/2023]
Abstract
Excessive ammonia (NH4+) discharge can lead to algal blooms and disrupt water sustainability, so its control is imperative. Although microbiology-triggered anammox process is promising, its application is limited due to time-consuming cultivation of specific microorganisms and need for skilled operation. To bypass these barriers, this study proposed and verified a photo-induced anammox technology that removes NH4+ and total nitrogen (TN) from water by ultraviolet (UV)/vacuum UV (VUV)/chlorine under anoxic conditions. Under the Cl/N mass ratio of 5:1, the anoxic VUV/UV/chlorine process achieved 66.8% removal of 10 mg-N/L NH4+ within 10 min along with 57.8% reduction in TN. Besides the evidence from TN loss, this study confirmed nitrogen gas (N2) as the primary degradation product at low dissolved oxygen (DO) concentration of 2.0 mg/L. The selective conversion of NH4+ into N2 was mainly attributed to reactive nitrogen species (RNS, 42.5%) and reactive chlorine species (RCS, 57.5%). The TN removal efficiency was insensitive to certain variations of pH (7.0-9.0), NH4+ concentration (1-30 mg-N/L), chloride (50-125 mg/L), and sulfate (25-100 mg/L), but sensitive to DO and bicarbonate (25-100 mg/L). Given its robustness and high efficiency, the anoxic VUV/UV/chlorine technology may serve as a potentially promising alternative for NH4+ and TN alleviation in wastewater.
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Affiliation(s)
- Wenzhe Liu
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Baiyang Chen
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China.
| | - Yang Yang
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Boqiang Li
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Huimei Pan
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
| | - Wang Luo
- State Key Laboratory of Urban Water Resource and Environment, Shenzhen Key Laboratory of Organic Pollution Prevention and Control, Harbin Institute of Technology, Shenzhen 518055, China
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5
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Chen S, Sheng X, Zhao Z, Cui F. Chemical-free vacuum ultraviolet irradiation as ultrafiltration membrane pretreatment technique: Performance, mechanisms and DBPs formation. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 351:119785. [PMID: 38081086 DOI: 10.1016/j.jenvman.2023.119785] [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: 07/09/2023] [Revised: 11/28/2023] [Accepted: 12/03/2023] [Indexed: 01/14/2024]
Abstract
Membrane fouling induced by natural organic matter (NOM) has seriously affected the further extensive application of ultrafiltration (UF). Herein, a simple, green and robust vacuum ultraviolet (VUV) technology was adopted as pretreatment before UF and ultraviolet (UV) technology was used for comparison. The results showed that control effect of VUV pretreatment on membrane fouling was better than that of UV pretreatment, as evidenced by the increase of normalized flux from 0.27 to 0.38 and 0.73 after 30 min UV or VUV pretreatment, respectively. This is related to the fact that VUV pretreatment exhibited stronger NOM degradation ability than UV pretreatment owing to the formation of HO•. The steady-state concentration of HO• was calculated as 3.04 × 10-13 M and the cumulative exposure of HO• reached 5.52 × 10-10 M s after 30 min of VUV irradiation. And the second-order rate constant between NOM and HO• was determined as 1.36 × 104 L mg-1 s-1. Furthermore, fluorescence EEM could be applied to predict membrane fouling induced by humic-enriched water. Standard blocking and cake filtration were major fouling mechanisms. Moreover, extension of UV pretreatment time increased the disinfection by-products (DBPs) formation, the DBPs concentration was enhanced from 322.36 to 1187.80 μg/L after 210 min pretreatment. However, VUV pretreatment for 150 min reduced DBPs content to 282.57 μg/L, and DBPs content continued to decrease with the extension of pretreatment time, revealing that VUV pretreatment achieved effective control of DBPs. The variation trend of cytotoxicity and health risk of DBPs was similar to that of DBPs concentration. In summary, VUV pretreatment exhibited excellent effect on membrane fouling alleviation, NOM degradation and DBPs control under a certain pretreatment time.
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Affiliation(s)
- Shengnan Chen
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China; Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
| | - Xin Sheng
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China; Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
| | - Zhiwei Zhao
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China; Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China.
| | - Fuyi Cui
- College of Environment and Ecology, Chongqing University, Chongqing, 400045, PR China; Key Laboratory of the Three Gorges Reservoir Region's Eco-environment, Ministry of Education, Chongqing University, Chongqing, 400045, PR China
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6
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Kreutz GK, Borba FH, Baroni S, Mayer I, Seibert D, Inticher JJ, Zorzo CF, Guimarães RE. Reduction of the environmental impact of wastewater from the pretreatment of biodiesel production: A hybrid proposal for decontamination via photo-electro-Fenton/Fered/O 3. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 342:118080. [PMID: 37196625 DOI: 10.1016/j.jenvman.2023.118080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/27/2023] [Accepted: 04/30/2023] [Indexed: 05/19/2023]
Abstract
Complex wastewater is generated during biodiesel production. We propose a new solution for the treatment of wastewater from enzymatic pretreatment of biodiesel production (WEPBP) by using a hybrid system based on the photo-Fered-Fenton process with O3 assistance (PEF-Fered-O3). We applied response surface methodology (RSM) to determine the suitable conditions for the PEF-Fered-O3 process: a current intensity of 3 A, an initial solution pH controlled at 6.4, an initial H2O2 concentration of 12,000 mg L-1, and an O3 concentration of 50 mg L-1. We performed three new experiments under similar conditions with slight changes to the conditions, namely a longer reaction time (120 min) and single or periodic H2O2 addition (i.e., small H2O2 additions at different reaction times). Periodic H2O2 addition provided the best removal results probably by reducing the occurrence of undesired side reactions that cause hydroxyl radical (•OH) scavenging. With the application of the hybrid system, the chemical oxygen demand (COD) and total organic carbon (TOC) decreased by 91% and 75%, respectively. We also evaluated the presence of metals such as iron, copper, and calcium; electric conductivity; and voltage at 5, 10, 15, 30, 45, 60, 90, and 120 min. We submitted raw and treated WEPBP sludge samples to X-ray diffraction to study the degree of crystallinity. There was a rearrangement of the compounds present in treated WEPBP, possibly caused by oxidation of a large fraction of organic matter. Finally, we evaluated the genotoxicity and cytotoxicity of WEPBP by using Allium cepa meristematic root cells. Treated WEPBP was less toxic to these cells, denoted by improvements in gene regulation and cell morphology. Given the current scenario for the biodiesel industry, applying the proposed hybrid PEF-Fered-O3 system at suitable conditions provides an efficient alternative to treat a complex matrix, namely WEPBP, to reduce its potential to cause abnormalities in the cells of living organisms. Thus, the negative impacts of the discharge of WEPBP in the environment might be reduced.
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Affiliation(s)
- Gustavo K Kreutz
- Postgraduate Program of Environment and Sustainable Technologies, Federal University of Fronteira Sul, Rua Jacob Reinaldo Haupenthal 1580, CEP: 97900-00, Cerro Largo, RS, Brazil
| | - Fernando H Borba
- Postgraduate Program of Environment and Sustainable Technologies, Federal University of Fronteira Sul, Rua Jacob Reinaldo Haupenthal 1580, CEP: 97900-00, Cerro Largo, RS, Brazil.
| | - Suzymeire Baroni
- Postgraduate Program of Environment and Sustainable Technologies, Federal University of Fronteira Sul, Rua Jacob Reinaldo Haupenthal 1580, CEP: 97900-00, Cerro Largo, RS, Brazil
| | - Ildemar Mayer
- Postgraduate Program of Environment and Sustainable Technologies, Federal University of Fronteira Sul, Rua Jacob Reinaldo Haupenthal 1580, CEP: 97900-00, Cerro Largo, RS, Brazil
| | - Daiana Seibert
- Postgraduate Program of Environment and Sustainable Technologies, Federal University of Fronteira Sul, Rua Jacob Reinaldo Haupenthal 1580, CEP: 97900-00, Cerro Largo, RS, Brazil
| | - Jonas J Inticher
- Postgraduate Program of Chemical Engineering, West Paraná State University, Rua da Faculdade 645, Jd. Santa Maria, 85903-000, Toledo, PR, Brazil
| | - Camila F Zorzo
- Federal University of Rio Grande do Sul, Hydraulic Research Institute, Postal code 15029, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil
| | - Raíssa E Guimarães
- Federal University of Rio Grande do Sul, Hydraulic Research Institute, Postal code 15029, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil
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7
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Dong S, Ding Y, Feng H, Xu J, Han J, Jiang W, Xia Y, Wang A. Source preventing mechanism of florfenicol resistance risk in water by VUV/UV/sulfite advanced reduction pretreatment. WATER RESEARCH 2023; 235:119876. [PMID: 36931185 DOI: 10.1016/j.watres.2023.119876] [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: 09/02/2022] [Revised: 02/13/2023] [Accepted: 03/12/2023] [Indexed: 06/18/2023]
Abstract
To avoid the inhibition of microbial activity and the emergence of bacterial resistance, effective abiotic pretreatment methods to eliminate the antibacterial activity of target antibiotics before the biotreatment system for antibiotic-containing wastewater are necessary. In this study, the VUV/UV/sulfite system was developed as a pretreatment technique for the source elimination of florfenicol (FLO) resistance risk. Compared with the VUV/UV/persulfate and sole VUV photolysis, the VUV/UV/sulfite system had the highest decomposition rate (0.33 min‒1) and the highest defluorination (83.0%), resulting in the efficient elimination of FLO antibacterial activity with less than 2.0% mineralization, which would effectively retain the carbon sources for the sludge microorganisms in the subsequent biotreatment process. Furthermore, H• was confirmed to play a more important role in the elimination of FLO antibacterial activity by controlling the environmental conditions for the formation and transformation of reactive species and adding their scavengers. Based on the theoretical calculation and proposed photolytic intermediates, the elimination of FLO antibacterial activity was achieved by dechlorination, defluorination and removal of sulfomethyl groups. When the pretreated FLO-containing wastewater entered the biological treatment unit, the abundance of associated antibiotic resistance genes (ARGs) and the relative abundance of integrons were efficiently prevented by approximately 55.4% and 22.9%, respectively. These results demonstrated that the VUV/UV/sulfite system could be adopted as a promising pretreatment option for the source elimination of FLO resistance risk by target decomposition of its responsible structures before the subsequent biotreatment process.
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Affiliation(s)
- Shuangjing Dong
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Yangcheng Ding
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China; School of Statistics and Mathematics, Zhejiang Gongshang University, Hangzhou 310018, P. R. China.
| | - Huajun Feng
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Jixiao Xu
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Jinglong Han
- State Key Lab of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, P. R. China
| | - Wenli Jiang
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720, United States
| | - Yijing Xia
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, P. R. China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou, 310018, P. R. China
| | - Aijie Wang
- State Key Lab of Urban Water Resource and Environment, School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, P. R. China; Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China
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8
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Ouyang WY, Wang WL, Zhang YL, Cai HY, Wu QY. VUV/UV oxidation performance for the elimination of recalcitrant aldehydes in water and its variation along the light-path. WATER RESEARCH 2023; 228:119390. [PMID: 36423547 DOI: 10.1016/j.watres.2022.119390] [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: 04/14/2022] [Revised: 10/19/2022] [Accepted: 11/18/2022] [Indexed: 06/16/2023]
Abstract
Vacuum ultraviolet/ultraviolet (VUV/UV) oxidation using a low-pressure mercury lamp emitting dual wavelengths (185 nm (VUV) and 254 nm (UV)) significantly varies in performance along the light-path (lP), which has not been fully characterized. Therefore, VUV/UV oxidation in solution was investigated at various lP in terms of the degradation kinetics and mineralization pathway of representative aldehydes with various alkyl-chain lengths. Oxidative degradation of parent aldehydes with shorter alkyl chains was less efficient, specifically the pseudo-zero-order rate constant (kobs) of formaldehyde was only 51% of that of propionaldehyde (kobs = 0.078 μM s-1). In contrast, the mineralization of aldehydes with longer alkyl chains was less efficient because these aldehydes underwent mineralization into more refractory carboxylic byproducts, e.g., oxalic acid. VUV was mainly absorbed by superficial water (lP < 0.55 cm), which resulted in highly heterogeneous oxidation in homogeneous water. Thus, kobs of acetaldehyde dramatically decreased from 0.13 to 0.033 μM s-1 as the total lP of solution increased from 1.0 to 3.0 cm. On the basis of mineralization pathways proposed above, an iterative kinetic model was developed to characterize the degradation of parent aldehydes and the formation of carboxylic acids along lP. This model predicted the VUV/UV oxidaton for the first time by considering the fast diffusion of pollutants by limited diffusion of transient radical species. Thus, it realized the prediction of •OH concentration at specific water solution and byproduct evolution within specific water solution in turbulent flow regime, wherein •OH was predominantly formed in superficial water-layers wherein •OH in water-layers of lP <0.16 cm and <0.81 cm contributed to 50% and 90% of the total oxidation performance, respectively. This result would help to improve the VUV-UV-reactor design in terms of optimizing the thickness of water-layer and turbulence of water-flow.
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Affiliation(s)
- Wan-Yue Ouyang
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (MARC), Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
| | - Wen-Long Wang
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (MARC), Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
| | - Yi-Lin Zhang
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (MARC), Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| | - Han-Ying Cai
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (MARC), Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China; Shenzhen Environmental Science and New Energy Technology Engineering Laboratory, Tsinghua-Berkeley Shenzhen Institute, Shenzhen 518055, PR China
| | - Qian-Yuan Wu
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (MARC), Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China
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9
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Huang H, Liang X, Li Q, Deng J, Zou J, Li X, Ma X, Li G, Chen G. High-performance reductive decomposition of trichloroacetamide by the vacuum-ultraviolet/sulfite process: Kinetics, mechanism and combined toxicity risk. WATER RESEARCH 2022; 225:119122. [PMID: 36152441 DOI: 10.1016/j.watres.2022.119122] [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: 07/15/2022] [Revised: 08/26/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Trichloroacetamide (TCAcAm) is among of the nitrogenous disinfection by-products (N-DBPs) with high cytotoxicity and genotoxicity, which is usually detected at low concentration (μg/L) in drinking water. In this study, advanced reduction process (ARP) based on vacuum ultraviolet (VUV) was employed to eliminate TCAcAm. Compared with VUV, VUV/sulfide, and VUV/ferrous iron processes, VUV/sulfite process demonstrated excellent performance for TCAcAm decomposition, the higher removal of TCAcAm could be achieved by VUV/sulfite process (85.6 %) than VUV direct photolysis (13.5 %) due to the production of a great number of reactive species. The degradation of TCAcAm followed the pseudo-first-order kinetics well in VUV/sulfite process, and the pseudo-first-order rate constant (kobs) increased with increasing sulfite concentration. Reactive species quenching experiments demonstrated that eaq-, SO3·- and H· were involved in the degradation of TCAcAm. The in situ generated eaq-, SO3·- and HO· via VUV/sulfite process were identified by electron paramagnetic resonance (EPR), and the eaq- was proved to be the dominated species (relative contribution: 83.5 %) for TCAcAm decomposition. The second-order rate constant of TCAcAm with eaq- was determined to be 2.41 × 1010 M-1 s-1 for the first time based on competitive kinetic method. The complete TCAcAm degradation could be achieved at pH > 8.3, while TCAcAm degradation efficiency decreased to 11.9 % at pH 5.8. TCAcAm decay could be divided into two stages: rapid growth (sulfite dosage: 0.25-1.0 mM) and slow growth (sulfite dosage: 1.0-4.0 mM). The yield of eaq- was controlled by sulfite dosage, and the predict yield of eaq- increased from 3.69 × 10-14 to 2.58 × 10-12 M with increasing the sulfite dosage from 0.25 to 4.0 mM by Kintecus 6.80, which resulted in an increase in TCAcAm removal. Meanwhile, the presence of dissolved oxygen (DO), chloride (Cl-), bicarbonate (HCO3-) and humic acid (HA) posed negative influence on TCAcAm decomposition to various degrees. Dichloroacetamide (DCAcAm), trichloroacetic acid (TCAA), dichloroacetic acid (DCAA) and Cl- were identified as intermediate products, indicated that reductive dechlorination and hydrolysis coexisted during the degradation of TCAcAm in VUV/sulfite process.
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Affiliation(s)
- Huahan Huang
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China; Key Laboratory of Water Resources Utilization and Protection, Xiamen city, Xiamen 361005, China
| | - Xinrui Liang
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China; Key Laboratory of Water Resources Utilization and Protection, Xiamen city, Xiamen 361005, China
| | - Qingsong Li
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China; Key Laboratory of Water Resources Utilization and Protection, Xiamen city, Xiamen 361005, China.
| | - Jing Deng
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310014, China
| | - Jing Zou
- College of Civil Engineering, Huaqiao University, Xiamen 361021, China
| | - Xia Li
- College of Civil Engineering, Fuzhou University, Fuzhou 350116, China
| | - Xiaoyan Ma
- College of Civil Engineering and Architecture, Zhejiang University of Technology, Hangzhou 310014, China
| | - Guoxin Li
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China
| | - Guoyuan Chen
- Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361005, China
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10
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Del Puerto O, Gonçalves NPF, Medana C, Prevot AB, Roslev P. Attenuation of toxicity and occurrence of degradation products of the fungicide tebuconazole after combined vacuum UV and UVC treatment of drinking water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:58312-58325. [PMID: 35364793 PMCID: PMC9395489 DOI: 10.1007/s11356-022-19691-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 03/09/2022] [Indexed: 06/10/2023]
Abstract
Antifungal azoles are the most frequently used fungicides worldwide and occur as active ingredients in many antifungal pharmaceuticals, biocides, and pesticides. Azole fungicides are frequent environmental contaminants and can affect the quality of surface waters, groundwater, and drinking water. This study examined the potential of combined vacuum UV (185 nm) and UVC (254 nm) irradiation (VUV/UVC) of the azole fungicide tebuconazole and the transformation product 1,2,4-trizole on degradation and changes in ecotoxicity. In vivo ecotoxicity was examined before and after UV treatment using bioassays with test organisms from different trophic levels to integrate changes in biological effect of the parent compound and the degradation products. The test battery included the luminescent bacterium Aliivibrio fischeri, the Gram-positive bacterium Bacillus subtilis, the fungus Fusarium graminearum, the green microalga Raphidocelis subcapitata, and the crustacean Daphnia magna. The combined VUV/UVC treatment of tebuconazole in drinking water efficiently degraded the parent compound at the µg/L-mg/L level and resulted in transformation products with lower toxicity than the parent compound. A direct positive correlation was observed between the applied UV dose (fluence, J/cm2), the disappearance of tebuconazole, and the decrease in ecotoxicity. The combined VUV/UVC process does not require addition of supplementary oxidants or catalysts and our study suggests that VUV/UVC-mediated photolysis of azole fungicides in water can decrease the overall toxicity and represent a potentially environmentally friendly treatment method.
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Affiliation(s)
- Oihane Del Puerto
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9200, Aalborg, Denmark
| | | | - Claudio Medana
- Dipartimento Di Biotechnologie Molecolari E Scienze Della Salute, Università Di Torino, Torino, Italy
| | | | - Peter Roslev
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9200, Aalborg, Denmark.
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