JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2024
·
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
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Xuecong Qian,Shilong Wang,Haijun Cheng,Ziye Jia,Da Wang,Yandong Xie,Jinhao Duan,Yu Tian,Jun Ma
The oxidation kinetics of Mn(II) by free chlorine is relatively low under near-neutral pH conditions which limits the Mn removal efficiency in drinking water treatment. Therefore, this study investigated the oxidation efficiency of Mn(II) by the UV-enhanced chlorination (UV/chlorine) system and identified the responsible reactive radical species. The results show that the oxidation kinetic of Mn(II) was greatly enhanced by the UV/chlorine system under near-neutral pH or even acidic conditions. The pseudo-first-order reaction rate of Mn(II) at pH 8.0 (within the first 20 min) increased from 2.60 × 10 −5 s −1 to 3.41 × 10 −4 s −1 . Based on the scavenging experiments and the steady-state kinetic modeling, ClO · and ClO 2 , whose steady-state concentration (∼10 −10 M and ∼10 −9 M, respectively at pH 8.0) was at least 4 orders of magnitude higher than that of HO · and Cl · , were recognized as the dominant reactive species contributing to the oxidation of Mn(II). Kinetic model calculations indicate that the contribution of ClO · to the oxidation of Mn(II) was consistently maintained above 70 %, and ClO 2 also played an important role in the oxidation of Mn(II) especially under acidic and alkaline conditions. In addition, the background components of HCO 3 − and Cl − had negligible influence on the oxidation efficiency because they barely changed the concentration of the ClO · and ClO 2 . This study first demonstrates the important role of ClO 2 in the oxidation of Mn(II) in the UV/chlorine system, and the possible role of ClO 2 in the degradation of some organic pollutants needs to be carefully evaluated in the future.
研究领域:
环境科学
·
化学工程
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产品关联
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Lingfei Ma,Chaoyi Wang,Haipu Li,Fangyuan Peng,Zhaoguang Yang
Geosmin (GSM) and 2-methylisoborneol (2-MIB) are two common odor compounds in drinking water . In this paper, the performance of UV/chlorine was compared with that of chlorine and UV to degrade GSM (100 ng L −1 ) and 2-MIB (100 ng L −1 ) in water. UV/chlorine was further exploited, and a steady-state kinetic model was used to conduct a detailed study on efficiency, rate, reactive species and pathway. The results showed that UV/chlorine greatly could improve the removal ratio to 90% within 5 min, from approximately 20% with only UV or dark chlorine in 60 min. The removal ratio and rate depended on UV light intensity , free chlorine dosage, reaction time and water quality parameters (e.g. pH, concentrations of HCO 3 − and Cl − ). Among these factors, the first two obviously could accelerate the rate and increase the ratio. The degradation was also significantly improved in an acidic condition, while alkaline conditions and HCO 3 − had inhibitory effects, and Cl − created no difference. Contributions of OH and Cl to the degradation of 2-MIB and GSM were further revealed, and OH was found to be the most important reactive species. In the UV/chlorine process, 6 degradation byproducts of 2-MIB, including 1 alcohol, 2 ketones, and 3 olefins , were identified, and 14 degradation byproducts of GSM, including 6 ketones, 1 aldehyde, 2 alcohols, 3 naphthenes , and 2 olefins, were found by using solid-phase microextraction coupled to gas chromatography-mass spectrometry. The possible degradation pathways of GSM and 2-MIB in UV/chlorine thus were proposed.
研究领域:
环境科学
·
饮用水处理
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2020
·
IF 9.13
Ze-Chen Gao,Yi-Li Lin,Bin Xu,Ying Xia,Chen-Yan Hu,Tian-Yang Zhang,Hao Qian,Tong-Cheng Cao,Nai-Yun Gao
The effect of bromide and iodide on the transformation of humic acid (HA) and algal organic matter (AOM), and the formation of disinfection by-products (DBPs) during UV/chlorination were investigated. Experimental results indicated that the halides effectively inhibited mineralization, with multiple changes in organic molecule transformation due to differences in formation and speciation of reactive halogen species and free halogen. As a consequence, bromide and iodide also played important roles in DBP formation. The DBP yields in HA-containing water during UV/chlorination decreased in the order of iodide loaded > freshwater ≫ bromide loaded, whereas DBP formation in AOM-containing water decreased remarkably with halides added (freshwater > bromide loaded ≫ iodide loaded) at high UV fluence . Moreover, Pearson correlation analysis exhibited weaker correlation between DBPs and water parameters in AOM-containing water, while DBPs in HA-containing water exhibited better correlation with water parameters. For both simulated waters, the theoretical toxicity was calculated and peaked in bromide-containing water, whereas the calculated toxicity in iodide-containing water was comparable or slightly higher than that in freshwater. Therefore, UV/chlorine treatment may achieve good quality water with reduced DBP-associated toxicity in freshwater or iodide-containing water (iodide only), but careful consideration is needed when purifying source waters containing bromide (bromide only), especially for AOM/bromide-containing water.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
高影响因子
Journal of Water Process Engineering
·
2021
·
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
✓ 已验证
产品关联
DOI
高影响因子
Water
·
2020
·Vol. 12
·期 11
·3150
·
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
·
毒理学
✓ 已验证
产品关联
DOI
高影响因子
Water
·
2019
·Vol. 11
·期 12
·2639
·
IF 2.524
Chi Wang,Zhian Ying,Ming Ma,Mingxin Huo,Wu Yang
The utilization of reclaimed water is a reliable and sustainable approach to enhance water supply in water-deficient cities. However, the presence of micro-organic pollutants (MPs) in reclaimed water has potential adverse effects on aquatic ecosystems and human health. In this study, we investigated the occurrence of 12 target MPs in the influent and reclaimed water collected from a local wastewater treatment plant, and the ultraviolet (UV)–chlorine process was applied to analyze its ability to remove MPs. The results showed that all 12 MPs were detected in both the influent and the reclaimed water, with the concentrations ranging from 25.5 to 238 ng/L and 8.6 to 42.5 ng/L, respectively. Over 52% of all the target MPs were readily degraded by the UV–chlorine process, and the removal efficiency was 7.7% to 64.2% higher than the corresponding removal efficiency by chlorination or UV irradiation only. The degradation efficiency increased with the increasing initial chlorine concentration. The pH value had a slight influence on the MP degradation and exhibited different trends for different MPs. The formation of known disinfectant byproducts (DBPs) during the UV–chlorine process was 33.8% to 68.4% of that in the chlorination process, but the DBPs’ formation potentials were 1.3 to 2.2 times higher. The toxicity assay indicated that UV–chlorine can effectively reduce the toxicity of reclaimed water.Keywords:MPs;UV–chlorine process;disinfectant byproducts;toxicity
研究领域:
环境科学
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水处理
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毒理学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Quanfa Zhong,Wangbao Gong,Guangjun Wang,Jun Xie,Jianshu Zhao,Qinghai Jin,Xiaoming Ma,Zhangxin Wang,Di He
This study utilized Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to investigate the molecular-level transformation of dissolved organic matter (DOM) during treatment with the novel UV/dichloroisocyanurate (NaDCC) process. Comparisons were made with conventional UV/hypochlorite (NaClO) and UV/monochloramine (NH 2 Cl) processes to assess the feasibility and environmental risks of UV/NaDCC. Results showed that UV/NaDCC and UV/NaClO had comparable and stronger DOM mineralization effects than UV/NH 2 Cl. Notably, UV/NaDCC treatment more effectively reduced DOM aromaticity, fluorescence, and apparent molecular weight, producing more oxidized and saturated molecules. Kendrick mass defect (KMD) analysis indicated that demethylation and carboxylation reactions played key roles in UV/NaDCC treatment, supported by a greater number of precursor-product pairs. The UV/NaDCC system produced substantial chlorinated and N-containing byproducts (Cl-BPs and N-BPs). Among the Cl-BPs, species formed via + 2Cl reaction ( e. g. , +H 2 Cl 2 O 2 , +Cl 2 O) were dominant, similar to the UV/NaClO system. The N-BPs with higher nitrogen content ( e. g. , N3 and N4) were more abundant than in UV/NH 2 Cl. The UV/NaDCC system produced the highest concentrations of TCM and DCAN, whereas the UV/NaClO system yielded the highest concentration of DCAA. Toxicity tests revealed that UV/NaDCC effluent displayed the highest toxicity. To the best of our knowledge, this study provides the first molecular-level insight into DOM transformation in UV/NaDCC treatment, offering theoretical and practical guidance for its application.
研究领域:
环境化学
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水处理技术
·
质谱分析
·
有机物分析
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副产物生成
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毒理学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2018
·
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
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2024
·
IF 7.6
Binbin Shao,Chenkai Hu,Hainan Zhao,Chengcheng Xiao,Erdeng Du,Anhong Cai,Jing Deng
Ambroxol (AMB) is a commonly used bromine-containing organic compound in medical applications and has been frequently found in water environments, which might pose risks of forming brominated disinfection by-products (Br-DBPs) in water treatment systems. The degradation kinetics as well as the degradation mechanism of AMB in the UV/chloramine process were investigated in this study. It was determined that reactive chlorine species (RCS) and the reactive nitrogen species (RNS) were the dominant free radicals for AMB degradation. Debromination occurred mainly in the initial stage of the degradation process, with a debromination rate of 34.5% at 10 min. Four possible degradation pathways of AMB were proposed based on liquid chromatography mass spectrometry (LC-MS) analysis as well as density functional theory (DFT) calculations, meanwhile the ECOSAR model was used to predict the toxicity risk of AMB and its degradation intermediates. Furthermore, after assessing the formation of DBPs during the UV/chloramine pre-oxidation process and conducting a toxicity risk analysis based on the results, it has been verified that this method can effectively remove AMB while reducing the formation potential of DBPs in the water environment. This suggests that the UV/chloramine process shows promise for treating bromine-containing organic compounds in real-world water treatment applications.
研究领域:
环境科学
·
水处理工程
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 25
·期 1
·672-682
·
IF 2.741
Shi Xue-Ting,Liu Yong-Ze,Tang Yu-Qing,Feng Li,Zhang Li-Qiu
UV/chlorine, as a novel disinfection method, has attracted great interest due to its effective removal for pathogenic microorganism and degradation of trace organic contaminants existed in water environment. This paper investigated the degradation kinetics and pathways of Bezafibrate (BZF), a typical antilipemic drug, during UV/chlorine process. The results showed that 92.3% of BZF was degraded after 20 min in UV/chlorine process. This indicated HO• and reactive chlorine species (RCSs) formed in UV/chlorine played the dominant role in degrading BZF. Observed rate constants of BZF degradation ( k
obs,BZF ) in UV/chlorine process increased linearly in a wide chlorine dosage from 0.1 to 1.0 mM, which implied that ClO• generated from the reactions of chlorine with HO• and Cl• could react with BZF rapidly. The steady-state kinetic modeling result proved this deduction and the rate constant of ClO• with BZF was fitted to be 5.0 × 10 8 M −1 s −1 . k
obs,BZF was affected by Cl − and HA. The total contribution of RCSs (including Cl•, Cl 2 • − , and ClO•) to the degradation of BZF was determined to be ~ 80%, which is much higher than that of HO•. Thirteen degradation products of BZF were identified by LC-MS/MS. Initial degradation products were arisen from hydroxylation, chlorine substitution and cyclization by HO• and RCSs, and then further oxidized to generate acylamino cleavage and demethylation products.
研究领域:
环境科学
·
水处理工程
✓ 已验证
DOI
PubMed
高影响因子
WATER RESEARCH
·
2021
·
IF 11.236
Bingliang Zhang,Xuening Wang,Zhuoyao Fang,Shu Wang,Chao Shan,Si Wei,Bingcai Pan
ABSTRACT Ultraviolet-based advanced oxidation processes (UV-AOPs) are very promising in advanced treatment of municipal secondary effluents. However, the transformation of dissolved effluent organic matter (dEfOM) in advanced treatment of real wastewater, particularly at molecular level, remains unclear. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) coupled with multiple statistical analysis were performed to better understand the transformation of dEfOM in UV/H 2 O 2 , UV/persulfate (UV/PS), and UV/chlorine treatments. An obvious increase in oxygen content of dEfOM was observed after every UV-AOPs treatment, and the detailed oxygenation processes were further uncovered by mass difference analysis based on 24 types of typical reactions. Generally, UV/H 2 O 2 process was subjected to the most oxygenation reactions with the typical tri-hydroxylation one (+3O), whereas di-hydroxylation reaction (+H 2 O 2 ) was dominant in UV/PS and UV/chlorine processes. Additionally, the three UV-AOPs shared the majority of precursors, and more proportions of unique products were identified for each process. The precursors with lower H/C and higher aromaticity were readily degraded by UV/chlorine over UV/H 2 O 2 and UV/PS, with the products featuring lower molecular weight. Moreover, dEfOM of high aromaticity tended to produce chlorinated byproducts through addition reactions in chlorination and UV/chlorine processes. Among these UV-AOPs, the highest reduction of both acute toxicity and specific UV absorbance at 254 nm (SUVA 254 ) was observed for UV/chlorine, implying the potential for UV/chlorine process in advanced treatment of wastewater. In addition, acute toxicity was highly correlated with SUVA 254 and CHOS compounds. This study is believed to help better understand the different fates of dEfOM in real wastewater during UV-AOPs treatment.
研究领域:
环境科学
·
废水处理
✓ 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）