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
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产品关联
DOI
高影响因子
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
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产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Jiahui Zhang,Wenliang Zhang,Yue Wang,Shaoyi Jiang,Yan Wang,Zhezheng Ding,Xiaomin Liu
2,4-dichlorophenoxyacetic (2,4-D) acid and 4-chlorophenoxyacetic acid (4-CPA), as widely utilized organochlorine pesticides , are normally detected in wastewater and atmosphere. Their harmfulness to the ecosystem cannot be ignored. UV/H 2 O 2 is one of the most conventional advanced oxidation processes, which has remarkable advantages for the removal of refractory organic pollutants in wastewater. However, the reaction mechanisms and pathways of pollutants with reactive radicals are still unclear. In this study, the degradation efficacy and mechanisms during the photodegradation of 2,4-D and 4-CPA in UV/H 2 O 2 processes were investigated by experiments and density functional theory calculations. The results showed that 2,4-D was more likely to be degraded by UV/H 2 O 2 treatment than UV photolysis alone. In contrast, 4-CPA can be degraded effectively and rapidly under UV irradiation alone. By LC-MS analysis, the degradation products of 2,4-D and 4-CPA in the UV/H 2 O 2 processes were identified and they were produced by hydroxylation and photolysis. Therefore, we speculated a competition mechanism presented between direct photolysis and indirect photolysis in the UV/H 2 O 2 degradation of 2,4-D and 4-CPA. The OH-initiated reaction mechanisms of 2,4-D and 4-CPA in aqueous environments were investigated using quantum chemical methods SMD/M06–2X/6–311++G (3df, 2p)//SMD/M06–2X/6-311 + G (d,p). The pH dependence of the reaction mechanisms and rate constants in their degradation process induced by ·OH was also investigated. The calculation results showed that the ionic forms (2,4-D - and 4-CPA - ) were more prone to react with ·OH in comparison to the corresponding molecular forms (2,4-D and 4-CPA). The total rate constants of 2,4-D and 4-CPA with OH increased with the pH from 1 to 10, and decreased with continued pH increase. The toxicities of 2,4-D, 4-CPA and their products were assessed by the QSAR-based toxicity evaluation software. The results showed that several products were more toxic than their parent compounds, such as 2,4-dichlorophenol, 3,5-dichlorocatechol, 4-chlorophenol and hydroquinone . This work can contribute to clarifying the environmental risks of 2,4-D and 4-CPA and offer a complete understanding for the photodegradation behavior of 2,4-D and 4-CPA in aqueous ecosystems.
研究领域:
环境科学
·
化学
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产品关联
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
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Ze-Chen Gao,Yi-Li Lin,Bin Xu,Ying Xia,Chen-Yan Hu,Tian-Yang Zhang,Tong-Cheng Cao,Yang Pan,Nai-Yun Gao
This study compared the degradation of dissolved organic matter (DOM) by UV/chlorine advanced oxidation processes (AOPs) with emerging ultraviolet light-emitting diode (UV-LED, 275 nm) and traditional low pressure UV (LPUV, 254 nm) as UV sources. Excitation emission matrix-parallel factor (EEM-PARAFAC) analysis and two-dimensional (2D) correlation gel permeation chromatograph were applied to explore the evolutions of DOM during oxidation processes. The degradation behaviors of DOM indicated by UV absorbance at 254 nm (UV 254 ), dissolved organic carbon (DOC), and fluorophores fitted the pseudo-first-order kinetics well. The removal efficiency of DOM was similar under UV-LED and LPUV irradiation alone. However, UV-LED exhibited much higher degradation rates (increased by 29–160%) than LPUV regardless of the tracking variables during UV/chlorine processes. For three PARAFAC components, humic-like fluorescences were preferentially degraded by UV/chlorine oxidation compared with protein-like fluorescence potentially due to the differences of electronic moieties and molecular weight (MW). The decline in UV 254 , DOC, and fluorophores increased with increasing chlorine dosage; linear correlations between those indicators were observed during the two AOPs. Moreover, UV-LED/chlorine could achieve greater extents of MW change. Our study demonstrated that UV-LED could be a superior alternative for the future selection of UV source in the UV/chlorine process.
研究领域:
环境科学
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水处理
·
化学工程
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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
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DOI
PubMed
高影响因子
Science of Advanced Materials
·
2019
·Vol. 11
·期 6
·842-853
·
IF 1.158
Xu Qiyao,Liu Hongxia,Zheng Huaili,Liang Jianjun
In this study, a new cationic polyacrylamide (CPAM) was successfully synthesized through UV-H2O2-initiated polymerization technique using acryloyloxyethyl trimethyl ammonium chloride (DAC) and acrylamide (AM) as monomers, and applied to sludge dewatering experiments.
Parameters affecting the molecular weight and conversion of the polymers, including total monomer concentration, monomer concentration of DAC, H2O2 concentration, pH and illumination time were examined. Fourier transform infrared spectroscopy (FT-IR), 1H nuclear
magnetic resonance spectroscopy (1H NMR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were employed to characterize the properties of the polymers. The results showed that CPAM was successfully synthesized and possessed a coarse and porous surface morphology
and inferior thermal stabilities. When the dosage of polymer was 40 mg L–1 and the initial sludge pH value was 7.0, PAD-3 (cationic degree: 40%, molecular weight: 6.89 × 106 Da) showed a more excellent sludge dewatering performance (FCMC: 70.6% SRF: 2.8 ×
1012 m · kg –1; d
50: 436.802 μm, Df
: 1.59). During the sludge flocculation process, three mechanisms containing charge neutralization, patching and bridging co-contributed to a prominent flocculation performance.
研究领域:
环境科学
·
高分子化学
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DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2023
·
IF 11.2
Biyang Zhu,Dongxiao Sun-Waterhouse,Lijun You
UV/H 2 O 2 process is increasingly used to degrade carbohydrates, though the underlying mechanisms remain unclear. This study aimed to fill this knowledge gap, focusing on mechanisms and energy consumption involved in hydroxyl radical (•OH)-mediated degradation of xylooligosaccharides (XOSs) in UV/H 2 O 2 system. Results showed that UV photolysis of H 2 O 2 generated large amounts of •OH radicals, and degradation kinetics of XOSs fitted with a pseudo-first-order model. Xylobiose (X 2 ) and xylotriose (X 3 ), main oligomers in XOSs, were attacked easier by •OH radicals. Their hydroxyl groups were largely converted to carbonyl groups and then carboxy groups . The cleavage rate of glucosidic bonds was slightly higher than that of pyranose ring, and exo -site glucosidic bonds were more easily cleaved than endo -site bonds. The terminal hydroxyl groups of xylitol were more efficiently oxidized than other hydroxyl groups of it, causing an initial accumulation of xylose . Oxidation products from xylitol and xylose included ketoses , aldoses , hydroxy acids and aldonic acids , indicating the complexity of •OH radical-induced XOSs degradation. Quantum chemistry calculations revealed 18 energetically viable reaction mechanisms, with the conversion of hydroxy-alkoxyl radicals to hydroxy acids being the most energetically favorable (energy barriers <0.90 kcal/mol). This study will provide more understanding of •OH radicals-mediated degradation of carbohydrates.
研究领域:
生物化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Shengnan Chen,Zhiwei Zhao,Li Li,Fuyi Cui
Ultrafiltration (UF) is widely used in drinking water plants, nevertheless, it still encounters challenges stemming from inevitable membrane fouling caused by natural organic matter (NOM). Herein, this work applied VUV/PS as UF membrane pretreatment and used UV/PS for comparison. VUV/PS system exhibited superior ability in removing NOM compared to UV/PS system. HO and SO 4 − played crucial roles in the degradation. [SO 4 − ]ss was notably higher than [HO ]ss in the systems, yet HO was of greater significance. [HO ]ss and [SO 4 − ]ss in the VUV/PS process were remarkably higher than those in the UV/PS process, due to the function of 185 nm photons. VUV/PS pretreatment basically recovered flux and effectively reduced fouling resistance, with better performance than UV/PS. Fouling mechanism was dominated by multiple mechanisms after UV/PS pretreatment, whereas it was transformed into pore blockage after VUV/PS pretreatment. Moreover, the UF effluent quality after VUV/PS pretreatment outperformed that of UV/PS but fell short of that without pretreatment, possibly due to the generation of abundant low MW substances under the action of HO and SO 4 − . After chlorine disinfection, UV/PS and VUV/PS pretreatments increased the DBPs production and cytotoxicity. Specifically, oxidant PS affected the membrane surface morphology and fouling behaviors, and had no obvious effect on interception performance and mechanical properties. In actual water treatment, VUV/PS and UV/PS pretreatments exhibited excellent performance in alleviating membrane fouling, improving water quality, and reducing DBPs formation and acute toxicity.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 35
·29592-29597
·
IF 3.289
Lei Cao,Qianqiu Tang,Gengchao Wang
Poly(3,4-ethylenedioxythiophene) (PEDOT) is a promising conductive polymer due to its high conductivity and optical transparency. However, two main challenges remain to be solved for its practical application, including improving the humidity stability and water resistance. Here, a novel cross-linkable copolymer of methacryloyloxyethyl isocyanate grafted poly(styrene sulfonate-co-2-hydroxyethyl acrylate) [MOI-P(SS-HEA)] is synthesized by a radical polymerization and condensation reaction. MOI-P(SS-HEA) is used as a multi-functional counter anion to obtain the UV-curable conductive dispersion of PEDOT:MOI-P(SS-HEA). The electrical conductivity, humidity stability, and water resistance of the cross-linked PEDOT:MOI-P(SS-HEA) [PEDOT:MOI-P(SS-HEA)-C] conductive films are investigated. The results indicate that the UV cross-linked reaction significantly improves the humidity stability and water resistance of the PEDOT:MOI-P(SS-HEA)-C conductive film.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Hang Liu,Junlong Liu,Yanchang Liu,Zhihao Qu,Siye Tian,Yuhong Zhang
In this work, the ZnO microsphere is prepared by hydrothermal method and modified with different concentrations of Eu. The morphology of ZnO:Eu sample shows flower-like microspheres with many nanosheets. The gas performance of ZnO:Eu microsphere is investigated for detecting NO 2 . Compared with pure ZnO, the response of ZnO:2 % Eu sensor is increased by 8 times, and the optimal operating temperature of that is decreased to 130 °C. Especially, the gas sensing properties of ZnO:2 % Eu sensor is enhanced under UV excitation. The recovery time of ZnO:Eu sensor is reduced by 1200 s, and the response is increased by 3.6 times under UV excitation. The above results show an increase in sensor response due to doping Eu and UV excitation. At last, the possible gas mechanism of ZnO:Eu is discussed with and without UV excitation. This finding provides important guidance for UV-assisted sensors to enhance NO 2 response.
研究领域:
材料科学
·
环境监测
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产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2022
·
IF 4.52
Yan Zhang,Cuiling Cao,Zhiwei Yang,Guangqun Jia,Xiaomao Liu,Xuemin Li,Zongyan Cui,Adan Li
Propolis is rich in flavonoids and phenolic acids , which has strong antioxidant capacity . Two methodologies for simultaneous determination of 20 phenolic compounds in propolis by HPLC-UV and HPLC-MS/MS were developed. The sample extraction and chromatographic separation conditions, and ultraviolet detection wavelength, as well as mass spectrometry parameters were selected and optimized. Under the optimized conditions, good linearities ( R 2 ≥0.998) were obtained for all analytes. The limits of quantification (LOQs) of the proposed methods by HPLC-UV and HPLC-MS/MS for all analytes were in the range of 0.02–0.1 mg/g and 0.05–0.2 mg/g, respectively, and the recoveries were in the range of 95.4 %− 109.5 % and 94.0 %− 106.8 % with the relative standard deviations (RSDs) in the range of 1.1 %− 7.5 % and 0.4 %− 11.1 %, respectively. The proposed methods were applied for the determination of 20 phenolic compounds in 13 propolis samples collected from China and Brazil. The detection results of the two methods are almost consistent with each other, indicating that both methods are applicable, and the inter-confirmation of the two methods can improve the accuracy of the determination of phenolic components in propolis.
研究领域:
植物化学
·
分析化学
·
药学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）