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Wang Q, Huang N, Wang W, Zhang Z, Qiu Y, Chen X, Xu A, Wu Y, Chen Z, Hu H. A novel route for urea abatement in UPW production: Pre-chlorination/VUV/UV under acidic circumstances and its enhancement mechanisms. JOURNAL OF HAZARDOUS MATERIALS 2024; 475:134836. [PMID: 38889471 DOI: 10.1016/j.jhazmat.2024.134836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 04/26/2024] [Accepted: 06/04/2024] [Indexed: 06/20/2024]
Abstract
Urea abatement has been a prominent challenge for UPW production. This research proposed a productive strategy combining pre-chlorination and VUV/UV processes under acidic conditions to settle this problem. This study first revealed the reaction kinetics between urea and free chlorine in a large pH range from 2.5 to 9.6, where the reaction constant rate varied from 0.06 to 0.46 M-1·s-1. Substitution reaction mediated by Cl2 was the dominant process at low pH (pH<3). The differences of dominant pathways resulted in the differences in reaction products: The detected concentration of dichloramine at pH 2.5 was twice that at pH 4.5 and 6.5. Further, this study found that pre-chlorination/VUV/UV process could achieve the thorough removal of 2-mg/L urea with chlorination of less than 5 min and VUV/UV irradiation of less than 200 mJ/cm2. Chloride ions, low pH, and higher chlorine dosage were found to be the positive factors to improve urea removal efficiency in pre-chlorination/VUV/UV process. The reaction rate constants between chlorourea with·OH and·Cl were calculated to be 3.62 × 107 and 2.26 × 109 L·mol-1·s-1, respectively.·Cl,·OH and photolysis contributed 60.5 %, 22.9 % and 16.6 % in chlorourea degradation, respectively. Pre-chlorination/VUV/UV achieved a DOC removal efficiency of 78.5 %. And nitrogen in urea was converted into inorganic nitrogenous compounds. Finally, compared with direct VUV/UV/chlorine and VUV/UV/persulfate processes, this process saved more than 70 % of energy in VUV/UV unit.
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Affiliation(s)
- Qi Wang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Nan Huang
- National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Beijing University of Technology, Beijing 100124, China.
| | - Wenlong Wang
- Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Zhuowei Zhang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Yu Qiu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Xiaowen Chen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China
| | - Ao Xu
- Research Institute for Environmental Innovation (Suzhou), Tsinghua University, Suzhou 215163, China
| | - Yinhu Wu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Zhuo Chen
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China
| | - Hongying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), School of Environment, Tsinghua University, Beijing 100084, China; Beijing Laboratory for Environmental Frontier Technologies, Beijing 100084, China.
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Long L, Wang S, Gao Z, You S, Wei L. Electro-oxidation and UV irradiation coupled method for in-site removing pollutants from human body fluids in swimming pool. JOURNAL OF HAZARDOUS MATERIALS 2024; 464:132963. [PMID: 37976850 DOI: 10.1016/j.jhazmat.2023.132963] [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: 06/25/2023] [Revised: 08/11/2023] [Accepted: 11/07/2023] [Indexed: 11/19/2023]
Abstract
A comprehensive study was conducted to investigate how ultraviolet (UV) irradiation combined with electrochemistry (EC) can efficiently remove human body fluids (HBFs) related pollutants, such as urea/creatinine/hippuric acid, from swimming pool water (SPW). In comparison with the chlorination, UV, EC, and UV/chlorine treatments, the EC/UV treatment exhibited the highest removal rates for these typical pollutants (TPs) from HBFs in synthetic SPW. Specifically, increasing the operating current of the EC/UV process from 20 to 60 mA, as well as NaCl content from 0.5 to 3.0 g/L, improved urea and creatinine degradation while having no influence on hippuric acid. In contrast, EC/UV process was resilient to changes in water parameters (pH, HCO3-, and actual water matrix). Urea removal was primarily attributable to reactive chlorine species (RCS), whereas creatinine and hippuric acid removal were primarily related to hydroxyl radical, UV photolysis, and RCS. In addition, the EC/UV procedure can lessen the propensity for creatinine and hippuric acid to generate disinfection by-products. We can therefore draw the conclusion that the EC/UV process is a green and efficient in-situ technology for removing HBFs related TPs from SPW with the benefits of needless chlorine-based chemical additive, easy operation, continuous disinfection efficiency, and fewer byproducts production.
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Affiliation(s)
- Liangchen Long
- School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090, China
| | - Shutao Wang
- School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090, China
| | - Zhelu Gao
- School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090, China
| | - Shijie You
- School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090, China.
| | - Liangliang Wei
- School of Environment, Harbin Institute of Technology, Harbin 150090, China; State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090, China.
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Lee JW, Lee D, Lee HJ, Shim S, Kim JH, Lee C. Enhanced oxidation of urea by pH swing during chlorination: pH-dependent reaction mechanism. WATER RESEARCH 2023; 242:120183. [PMID: 37320874 DOI: 10.1016/j.watres.2023.120183] [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: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 06/17/2023]
Abstract
Urea reacts with chlorine to form chlorinated ureas (chloroureas), and fully chlorinated urea (tetrachlorourea) is further hydrolyzed into CO2 and chloramines. This study found that the oxidative degradation of urea by chlorination was enhanced by the pH swing, wherein the reaction proceeded under an acidic pH (e.g., pH = 3) in the first stage, and the solution pH was subsequently increased to a neutral or alkaline value (e.g., pH > 7) in the second-stage reaction. The degradation rate of urea by pH-swing chlorination increased with increasing chlorine dose and pH during the second-stage reaction. The pH-swing chlorination was based on the opposite pH dependence of sub-processes comprising urea chlorination. The formation of monochlorourea was favored under acidic pH conditions; however, the subsequent conversion into di- and trichloroureas was favored under neutral or alkaline pH conditions. The deprotonation of monochlorourea (pKa = 9.7 ± 1.1) and dichlorourea (pKa = 5.1 ± 1.4) was suggested to be responsible for the accelerated reaction in the second stage under increased pH conditions. pH-swing chlorination was also effective in degrading urea at low concentrations (micromolar levels). In addition, the total nitrogen concentration significantly decreased during the degradation of urea because of the volatilization of chloramines and the release of other gaseous nitrogen compounds.
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Affiliation(s)
- Ji Won Lee
- School of Chemical and Biological Engineering, Institute of Chemical Process (ICP), and Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Donghyun Lee
- School of Chemical and Biological Engineering, Institute of Chemical Process (ICP), and Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Hye-Jin Lee
- School of Chemical and Biological Engineering, Institute of Chemical Process (ICP), and Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea
| | - Soojin Shim
- Infra Engineering Group, Global Infra Technology, Samsung Electronics, 1 Samsungjeonja-ro, Hwaseong-si, Gyeonggi-do 18448, South Korea
| | - Je Hun Kim
- Infra Engineering Group, Global Infra Technology, Samsung Electronics, 1 Samsungjeonja-ro, Hwaseong-si, Gyeonggi-do 18448, South Korea
| | - Changha Lee
- School of Chemical and Biological Engineering, Institute of Chemical Process (ICP), and Institute of Engineering Research, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, South Korea.
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Shan P, Lin J, Zhai Y, Dong S, How ZT, Qin R. Transformation and toxicity studies of UV filter diethylamino hydroxybenzoyl hexyl benzoate in the swimming pools. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163498. [PMID: 37068670 DOI: 10.1016/j.scitotenv.2023.163498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 06/01/2023]
Abstract
Diethylamino hydroxybenzoyl hexyl benzoate (DHHB), an ultraviolet (UV) filter, can be found in sunscreens and other personal care products and thus can be introduced into swimming pools through the swimmers. In outdoor pools, DHHB will inevitably interact with free chlorine and sunlight. Therefore, the mechanism of solar‑chlorine chemical transformation of DHHB, as well as the environmental risk, were investigated in this work. In chlorinated with solar (Cl + solar) process, free chlorine was the dominant contributor to 85% of the DHHB degradation, while hydroxyl radicals and reactive chlorine species contributed only 15% because of low free radical generation and fast DHHB and free chlorine reaction rates. Scavenging matrices, such as Cl-, NH4+, and dissolved organic matter (DOM), inhibited the degradation of DHHB in the Cl + solar process, while Br-, HCO3-, NO3-, and urea promoted DHHB degradation. DHHB degradation was inhibited in tap water swimming pool samples, while it was enhanced in seawater pool samples by the Cl + solar process. Seven transformation by-products (TBPs) including mono-, dichlorinated, dealkylate, and monochloro-hydroxylated TBPs were identified. Three degradation pathways, chlorine substitution, chlorine and hydroxyl substitution, and dealkylation were proposed for DHHB transformation in the Cl + solar process. Both Quantitative structure-activity relationship and Aliivibrio fischeri toxicity tests demonstrated increased toxicity for the chlorinated TBPs. A risk assessment of the DHHB and its TBPs suggested that both DHHB and its chlorinated TBPs pose a significant health risk.
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Affiliation(s)
- Panduo Shan
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Jiayi Lin
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Yanbo Zhai
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Shuai Dong
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan 570228, PR China
| | - Zuo Tong How
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China
| | - Rui Qin
- Key Laboratory of Agro-Forestry Environmental Processes and Ecological Regulation of Hainan Province, School of Ecology and Environment, Hainan University, Haikou, Hainan 570228, PR China.
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Zhang X, Zhai J, Lei Y, Huang H, Ren P, Lambropoulou D, Yang X. Enhanced formation of trichloronitromethane precursors during UV/monochloramine treatment. JOURNAL OF HAZARDOUS MATERIALS 2022; 422:126813. [PMID: 34399222 DOI: 10.1016/j.jhazmat.2021.126813] [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: 04/27/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 05/28/2023]
Abstract
This study systematically investigates the formation of trichloronitromethane (TCNM) from 2 natural waters, 6 humic substances and 16 phenolic compounds during UV/monochloramine (UV/NH2Cl) followed by post-chloramination. Using 15N-NH2Cl as an isotope tracer, we found that 15N-TCNM accounted for 70.7-76.5% of total TCNM during UV/NH2Cl treated 2 natural waters, which was significantly higher than the proportion of 15N-TCNM in chloramination (NH2Cl alone). This is a direct evidence that NH2Cl, rather than the nitrogenous matters in waters, was the predominant nitrogen source of TCNM during UV/NH2Cl treatment. Phenol derivatives with meta-substituents and with electron-withdrawing groups facilitated the formation of TCNM precursors during UV/NH2Cl treatment. Significant correlations were found between Hammett constants (σ) of substituents and TCNM formation potentials. The formation mechanisms of TCNM were revealed using resorcinol as a representative phenolic compound. During UV/NH2Cl treatment, HO•, reactive chlorine species and reactive nitrogen species contributed to 28.1%, 29.0% and 19.4% of resorcinol degradation. Five nitro(so)-intermediates were identified as the main TCNM precursors. The formation pathways of TCNM were proposed. Alkaline pH was recommended to reduce the formation of TCNM precursors during UV/NH2Cl treatment.
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Affiliation(s)
- Xinran Zhang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China; Key Laboratory of Groundwater Resources and Environment (Jilin University), Ministry of Education, Changchun 130021, China
| | - Jiaxin Zhai
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Yu Lei
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Huang Huang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Pengfei Ren
- Guangzhou Municipal Engineering Design & Research Institute CO. Ltd., Guangzhou 510275, China
| | - Dimitra Lambropoulou
- Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece; Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, GR-570 01 Thessaloniki, Greece
| | - Xin Yang
- School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Sun Yat-sen University, Guangzhou 510275, China.
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Wang Y, Dong H, Qin W, Li J, Qiang Z. Activation of organic chloramine by UV photolysis: A non-negligible oxidant for micro-pollutant abatement and disinfection by-product formation. WATER RESEARCH 2021; 207:117795. [PMID: 34736003 DOI: 10.1016/j.watres.2021.117795] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/05/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Due to the wide-presence of organic amines in natural waters, organic chloramines are commonly formed during (pre-)chlorination. With the increasing application of UV disinfection in water treatment, both the activation mechanism of organic chloramine by UV photolysis and its subsequent impact on water quality are not clear. Using sarcosine (Sar) as an amine group-containing compound, it was found that organic chloramines (i.e., Cl-Sar) would be firstly formed during chlorination even in the presence of natural organic matter. Compared with self-decay of Cl-Sar, UV photolysis accelerated Cl-Sar decomposition and induced NCl bond cleavage. Using metoprolol (MTP) as a model micro-pollutant, UV-activated Cl-Sar (UV/Cl-Sar) can accelerate micro-pollutant degradation, attributed to reactive radicals formation. HO• and Cl• were important contributors, with a total contribution of 45%‒64%. Moreover, the degradation rate of MTP by UV/Cl-Sar was pH-dependent, which monotonically increased from 0.044 to 0.065 min‒1 under pHs 5.5‒8.5. Although the activation of organic chloramine by UV could accelerate micro-pollutant degradation, UV/Cl-Sar treatment could also enhance disinfection by-products formation. Trichloromethane (TCM) formation was observed during MTP degradation by UV/Cl-Sar. After post-chlorination, TCM, 1,1-dichloropropanone, 1,1,1-trichloropropanone, and dichloroacetonitrile were detected. Their individual and total concentrations were all positively proportional to UV/Cl-Sar treatment time. The total concentration with 30 min treatment (66.93 μg L‒1) was about 2.3 times that with 1 min treatment (28.76 μg L‒1). Finally, the accelerated effect was verified with Cl-glycine and Cl-alanine. It is expected to unravel the non-negligible role of organic chloramine on water quality during UV disinfection.
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Affiliation(s)
- Yan Wang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuang-qing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Huiyu Dong
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuang-qing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenlei Qin
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuang-qing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Li
- School of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China.
| | - Zhimin Qiang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuang-qing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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