JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2024
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IF 4.1
Duanyang Wu,Shengnan Zhang,Jing Xu,Wei Cheng
Carbamazepine (CBZ) is a ubiquitous persistent micropollutant in water. This study evaluated the degradation of CBZ by UV/Chlorine process. The influencing factors, such as chlorine dosage, solution pH, and water matrix constituents (Cl − , HCO 3 – and NOM) on CBZ removal were systematically investigated. The reactive HO•, Cl• and ClO• species were mainly responsible for the degradation of CBZ, and their contributions determined by probes (Benzoic acid, Nitrobenzene and 1,4-Dimethoxybenzene) varied with pH. Theoretical quantum calculations involving a total of 79 transition states suggested that HO• attack CBZ by hydrogen atom transfer (HAT) and radical adduct formation (RAF) mechanisms, while Cl• and ClO• proceed mainly through HAT and RAF mechanism, respectively. The reaction rates between CBZ and free radicals were calculated by evaluating the energy barriers and transition states. Furthermore, the proposed formation pathways and reaction mechanisms of main hydroxylated products and chlorine substituted products were unequivocally authenticated by transition states calculations. Overall, this study combined experimental and computational approaches to provide an in-depth degradation mechanism of CBZ in UV/Chlorine process.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
Journal of Water Process Engineering
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2021
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IF 5.485
Jinxin Lu,Jiaqi Li,Jianye Xu,Huili Tang,Zhen Lv,Erdeng Du,Liping Wang,Mingguo Peng
The UV/chlorine process is a novel light-driven oxidation technique. In this study, norfloxacin (NOR), a typical quinolone contaminant, was degraded by using the UV/chlorine process. The effects of the process parameters were also investigated. The UV/chlorine process was observed to be capable of fully removing NOR in 360 s with a high degradation rate constant of 0.0196 s −1 . NOR degradation was found to be positively correlated with chlorine dose and UV intensity but negatively correlated with ammonia. FMO, MSPA, and CDFT quantum chemical structure analyses reveal the most reactive sites for electrophilic or radical attack are the N6 or N5 atoms in the piperazine ring of the NOR molecule, which are also potential starting reaction sites for the degradation process. Thirteen degradation intermediates were detected and identified by UPLC/Q-TOF HRMS . Three sub-pathways are present during the degradation process, including cleavage and removal of the piperazine ring, transformation and cleavage of the quinolone structure, and chlorination reaction with chlorine active matter (RCS). The full elimination of NOR does not ensure a decrease in acute toxicity. Environmental risks associated with the UV/chlorine process need to be assessed further.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
Water
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2020
·Vol. 12
·期 11
·3150
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IF 2.544
Jianye Xu,Siqi Zhou,Erdeng Du,Yongjun Sha,Lu Zheng,Mingguo Peng,Ling Ling
The UV/chlorine process, as a new type of AOP (Advanced Oxidation Process), was utilized to treat amlodipine (AML)-containing water. The influencing factors, including chlorine dose, UV intensity, solution initial pH value, and ammonia concentration, were investigated. The degradation of AML in real water and the relative contributions of OH• and Cl• were also studied. Finally, high-resolution mass spectrometry (HRMS) and GC-MS were used to identify the possible degradation products. The results demonstrated that the AML degradation process was fitted with apparent first-order kinetics. AML degradation had a positive correlation with UV intensity and chlorine dose, and a negative correlation with ammonia concentration. In the presence of ammonia nitrogen and DOM, the removal of AML from real water was reduced. OH• made a dominant percentage contribution of 55.7% to the degradation of AML. Sixteen intermediates were detected and identified. A possible degradation mechanism was also proposed. Acute toxicity tests and risk prediction both illustrated that the complete removal of AML does not guarantee the reduction of acute toxicity, but a prolonged degradation promoted the detoxification of toxic intermediates. The UV/chlorine process can be regarded to be an effective method to remove AML and reduce ecological risk.Keywords:Amlodipine;UV/chlorine;influencing factors;degradation products;ecological risk
研究领域:
环境科学
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毒理学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2018
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IF 3.927
Huiming Xiang,Yisheng Shao,Naiyun Gao,Xian Lu,Na An,Chaoqun Tan,Zhaofang Zheng
The degradation of diuron by chlorination and UV/chlorine process and the formation of disinfection by-products (DBPs) was investigated in this study. The degradation of diuron followed the pseudo first-order kinetics model. In UV/chlorine process, hydroxyl radical were proved to provide more contribution in the oxidation. The degradation kinetics increased with the increasing of chlorine dosage and the decreasing of natural organic matter (NOM) dosage. However, the degradation pathways were defined using high performance liquid chromatography coupled with a TSQ Quantum quadrupole mass spectrometer (HPLC-ESI/MS). The formation of DBPs after chlorination and chloramination was defined using gas chromatography with elect ion capture detector (GC-ECD) and gas chromatography–mass spectrometer (GC–MS). Several kinds of DBPs including chloroform (TCM), 1,1-dichloroacetone (1,1-DCP), 1,1,1-trichloroacetone (1,1,1-TCP), trichloronitromethane (TCNM), dichloroacetamide (DCAcAm) and trichloroacetamide (TCAcAm) was identified in this study.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2019
·Vol. 26
·期 24
·25012-25025
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IF 2.914
Li Jiaqi,Zhou Siqi,Li Miao,Du Erdeng,Liu Xiang
The removal of acetaminophen (AAP) in aqueous solution by the UV/chlorine process was evaluated. The effect of chlorine dose, the initial AAP concentration, pH value, and UV intensity on the reaction were also investigated. The degradation mechanism and the ecological risk were further discussed. The results indicated that AAP degradation fitted pseudo-first-order kinetics. Compared with UV alone or dark chlorination, the combination of UV and chlorine significantly accelerated the degradation process. The AAP degradation was positively affected by chlorine dose and UV intensity, while negatively affected by the initial AAP concentration and ammonia nitrogen concentration during the UV/chlorine process. The frontier orbital theory analysis shows that the C5 position in the benzene ring of AAP is likely to be the first site attacked by HO• and Cl• radical to form the products. Twelve intermediates were identified by Q-TOF and GC-MS. The possible degradation pathways were also proposed. Luminescent bacteria experiment and ECOSAR prediction both revealed that acute toxicity of AAP degradation could only be partially reduced. Ecological risks during the UV/chlorine process need to be further evaluated.
研究领域:
环境科学
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毒理学
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化学工程
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
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2023
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IF 12.8
Yinqiao Zhang,Yang Guo,Jingyun Fang,Kaiheng Guo,Gang Yu,Yujue Wang
Micropollutant (MP) abatement efficiencies are critical information for optimizing water treatment process for cost-effective operations. Nevertheless, due to the vast number of MPs in real water matrices, it is infeasible to measure their abatement efficiencies individually in practical applications. In this study, a probe compound-based kinetic model was developed for generalized prediction of MP abatement in various water matrices by the ultraviolet (UV)/chlorine process. The results show that by measuring the depletion of three probe compounds (ibuprofen, primidone, and dimetridazole) spiked in the water matrix, the exposures of main reactive chlorine species (RCS including chlorine radicals (Cl•), dichloride radicals ( Cl 2 − • ) and chlorine oxide radicals (ClO•)) and hydroxyl radicals (•OH) during the UV/chlorine process could be calculated using the model. Based on the determined exposures, the abatement efficiencies of various MPs in different water matrices (e.g., surface water, groundwater, and wastewater) could generally be predicted with acceptable accuracy by the model without prior water-specific calibration. In addition, the relative contribution of UV photolysis and oxidation with active chlorine, RCS, and •OH to MP abatement could be quantitatively simulated using the model to clarify the abatement mechanism of MPs during the UV/chlorine process. The probe-based kinetic model can thus offer a useful tool to guide practical water and wastewater treatment for MP abatement and to explore the mechanism of UV/chlorine process.
研究领域:
环境工程
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水处理
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化学工程
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环境科学
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
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2020
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IF 9.13
Yinqiao Zhang,Huijiao Wang,Yang Li,Bin Wang,Jun Huang,Shubo Deng,Gang Yu,Yujue Wang
The ultraviolet/chlorine (UV/Cl 2 ) process is an emerging advanced oxidation technology for micropollutant abatement in water and wastewater treatment . However, the application of the conventional UV/Cl 2 process in decentralized systems is limited by the transport and management of liquid chlorine. To overcome this limitation, this study evaluated an electrochemically driven UV/Cl 2 (E-UV/Cl 2 ) process for micropollutant abatement under conditions simulating decentralized water treatment . The E-UV/Cl 2 process combines UV irradiation with in situ electrochemical Cl 2 production from anodic oxidation of chloride (Cl − ) in source waters. The results show that with typical Cl − concentrations present in water sources for decentralized systems (30–300 mg/L Cl − ), sufficient amounts of chlorine could be quickly electrochemically produced at the anode to enable E-UV/Cl 2 process for water treatment. Due to its multiple mechanisms for micropollutant abatement (direct photolysis, direct electrolysis, Cl 2 -mediated oxidation, as well as hydroxyl radical and reactive chlorine species oxidation), the E-UV/Cl 2 process effectively eliminated all micropollutants (trimethoprim, ciprofloxacin, metoprolol, and carbamazepine) spiked in a surface water in 5 min. In contrast, at least one micropollutant with ∼20–80% residual concentrations could still be detected in the water treated by 10 min of UV irradiation, chlorination, electrolysis, and the conventional UV/Cl 2 process under similar experimental conditions. The electrical energy per order (E EO ) for micropollutant abatement ranged from 0.15 to 1.8 kWh/m 3 for the E-UV/Cl 2 process, which is generally comparable to that for the conventional UV/Cl 2 process (0.14–2.7 kWh/m 3 ). These results suggest that by in-situ generating Cl 2 from anodic oxidation of Cl − , the E-UV/Cl 2 process can overcome the barrier of the conventional UV/Cl 2 process and thus provide a promising technology for micropollutant abatement in decentralized water treatment systems.
研究领域:
环境科学
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水处理
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化学工程
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电化学
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高级氧化工艺
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）