CHEMOSPHERE
·
2019
·
IF 5.108
Pengchao Xie,Yujia Zou,Shan Jiang,Jingwen Wang,Li Zhang,Zongping Wang,Siyang Yue,Xiaonan Feng
Degradation of imipramine (IMI) in the VUV system (VUV 185 + UV 254 ) was firstly evaluated in this study. Both HO • oxidation and UV 254 direct photolysis accounted for IMI degradation. The quantum yields of UV 254 direct photolysis of deprotonated and protonated IMI were 1.31 × 10 − 2 and 3.31 × 10 − 3 , respectively, resulting in the higher degradation efficiency of IMI at basic condition. Increasing the initial IMI concentration lowered the degradation efficiency of IMI. While elevating reaction temperature significantly improved IMI degradation efficiency through the promotion of both the quantum yields of HO • and the UV 254 direct photolysis rate. The apparent activation energy was calculated to be about 26.6 kJ mol −1 . Negative-linear relationships between the k obs of IMI degradation and the concentrations of HCO 3 − /CO 3 2− , NOM and Cl − were obtained. The degradation pathways were proposed that cleavage of side chain and hydroxylation of iminodibenzyl and methyl groups were considered as the initial steps for IMI degradation in the VUV system. Although some high toxic intermediate products would be produced, they can be further transformed to other lower toxic products. The good degradation efficiency of IMI under realistic water matrices further suggests that the VUV system would be a good method to degrade IMI in aquatic environment.
研究领域:
环境科学
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药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Xiaoyan Liang,Jianhua Cheng,Cao Yang,Shewei Yang
In this study, four photochemical reaction parameters, including the reaction atmosphere, extra inorganic oxidant, inorganic anion and organic matter, were investigated in an aqueous environment to determine their effects on perfluorooctanoic acid (PFOA) photodecomposition. The photochemical defluorination of PFOA was conducted by vacuum ultraviolet light (VUV) using ferric ions as the catalyst. Both direct photolysis and photocatalysis were involved in the reaction. PFOA was completely decomposed by VUV irradiation with and without ferric ions within 72 or 144 h, respectively. There was no significant evidence indicating that the type of atmosphere (oxygen, nitrogen, or air) had any effect on the decomposition results. However, OH radicals generated during the photolysis process profoundly affected the decomposition of PFOA. The introduction of persulfate inhibited the mineralization of PFOA in the VUV/Fe 3+ system. Inorganic anions hindered the defluorination of PFOA in the following order: HCO 3 − > SO 4 2− > NO 3 − ∼ Cl − > ClO 4 − . The adverse effects of organic matter, including volatile organic compounds and dissolved natural organic compounds, were also examined. This study is beneficial to the understanding of the photodecomposition of other similar perfluorinated compounds (PFCs).
研究领域:
环境科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2016
·Vol. 18
·期 19
·13554-13563
·
IF 4.449
Yanmin Tao,Yongjun Hu,Weizhan Xiao,Jiwen Guan,Fuyi Liu,Xiaobin Shan,Liusi Sheng
Photoionization and dissociation of the 1-propanol dimer and subsequent fragmentations have been investigated by synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry and theoretical calculations. Besides the protonated monomer cation (C3H7OH)·H+ (m/z = 61) and Cα–Cβ bond cleavage fragment CH2O·(C3H7OH)H+ (m/z = 91), the measured mass spectrum at an incident photon energy of 13 eV suggests a new dissociation channel resulting in the formation of the (C3H7OH)·H+·(C2H5OH) (m/z = 107) fragment. The appearance energies of the fragments (C3H7OH)·H+, CH2O·(C3H7OH)H+ and (C3H7OH)·H+·(C2H5OH) are measured at 10.05 ± 0.05 eV, 9.48 ± 0.05 eV, and 12.8 ± 0.1 eV, respectively, by scanning photoionization efficiency (PIE) spectra. The 1-propanol ion fragments as a function of VUV photon energy were interpreted with the aid of theoretical calculations. In addition to O–H and Cα–Cβ bond cleavage, a new dissociation channel related to Cβ–Cγ bond cleavage opens. In this channel, molecular rearrangement (proton transfer and hydrogen transfer after surmounting an energy barrier) gives rise to the generated complex, which then dissociates to produce the mixed propanol/ethanol proton bound cation (C3H7OH)·H+·(C2H5OH). This new dissociation channel has not been reported in previous studies of ethanol and acetic acid dimers. The photoionization and dissociation processes of the 1-propanol dimer are described in the photon energy range of 9–15 eV.
研究领域:
化学物理学
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分子光谱学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COMBUSTION AND FLAME
·
2026
·
IF 6.2
Cheng-Yin Ye,Ling-Nan Wu,Dong-Xu Tian,Jiu-Zhong Yang,Long Zhao,Zhen-Yu Tian
The pyrolysis of pyridine, a model compound for fuel-nitrogen in coal, biomass, and tar, was investigated in a flow reactor at a pressure of 30 Torr and a temperature range from 773 to 1473 K. Twenty-seven species, including three radicals, three sets of isomers, nine hydrocarbons and nine nitrogenous species, were identified and quantified by synchrotron vacuum ultraviolet photoionization mass spectrometry. Several intermediates were newly detected compared with previous pyridine pyrolysis studies based on the photoionization efficiency spectra including cyanides, a benzene isomer, and resonance-stabilized radicals (propargyl and benzyl radicals). A new kinetic model for pyridine pyrolysis was developed and validated against the measured data. Kinetic modeling, rate-of-production and sensitivity analysis were performed to reveal the pyrolysis kinetics of pyridine and the formation of the key products. The results indicate that the decomposition of pyridine is dominated by the H-abstraction reactions. Hydrocarbon radicals, alkenes and alkynes are mainly produced by the elimination of HCN from nitrogenous intermediates. The formation of nitrogenous products relates to the removal of acetylene from pyridine. A new growth route from C 3 HN to C 5 HN and C 7 HN was observed and analyzed, which has not been reported previously regarding the pyrolysis studies of fuel-N. By comparing the pyridine pyrolysis with pyrrole pyrolysis experiments, the influence of different C-N bond structures on reaction mechanisms and product distributions was revealed. Results of this work are helpful in deepening the understanding of pyridine conversion behaviors related to coal and biomass combustion and conversion processes.
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Dan Li,Liangchen Long,Wei Xia,Weixin Zhao,Likui Feng,Xinhui Xia,Shufei He,Yu Liu,Shijie You,Liangliang Wei
Human body fluids related pollutants (BFPs) are primary precursors to disinfection by-products (DBPs) in swimming pool water (SPW). This study evaluated the degradation efficiency of ultraviolet/vacuum ultraviolet (UV/VUV) technology for the removal of three typical BFPs: urea, creatinine, and hippuric acid. The results showed that UV/VUV irradiation significantly enhanced the removal of these pollutants compared to UV alone. In addition, the observed rate constant (k obs ) of the UV/VUV system was 1.9–8.0 times higher than that of the UV/H 2 O 2 system, accompanied by a substantial 89.6 % reduction in the electrical energy per order (EEO). Urea degradation primarily involved the cleavage of C-N and C-H bonds within the urea molecule induced by VUV photolysis, whereas the degradation of creatinine and hippuric acid was mainly driven by a series of reactions (including decarboxylation, demethylation, hydroxylation, and ring opening) initiated by •OH. pH variations within the range of 6.8–8.2 exerted minimal impact on pollutant removal. However, NO 3 , humic acid, and cyanuric acid obviously inhibited the removal of BFPs. Employing UV/VUV system as a pretreatment step prior to chlorination disinfection led to a noteworthy reduction of 63.6 %-69.1 % of the adsorbable chlorine in actual SPW. Results of this study presented a green, chemical-free, and operationally simple method to mitigate DBPs formation in SPW.
研究领域:
环境科学
·
公共卫生
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL RESEARCH
·
2021
·
IF 6.498
Juan Li,Qi Zhang,Baiyang Chen,Lei Wang,Rongshu Zhu,Jie Yang
Understanding the formation and transformation of radicals generated by a low pressure mercury lamp emitting both 254 nm ultraviolet (UV 254 ) and 185 nm vacuum UV (VUV 185 ) is currently challenging due to the complexity of concurrent redox reactions occurring in this complex system. Because hydrogen peroxide (H 2 O 2 ) is a common product of both oxidizing and reducing radicals generated during the VUV irradiation process, monitoring the variations in H 2 O 2 levels can help us better understand the presence and relative dominance of different radicals. In this study, we systematically evaluated the effects of several selected anions on the formation of H 2 O 2 under a variety of pH and dissolved oxygen (DO) conditions. Results show that although addition of these anions inhibited the formation of H 2 O 2 , their H 2 O 2 -inhibition mechanisms are markedly different. At low concentrations (≤1.0 mg/L), chloride reduced the generation of H 2 O 2 primarily by consuming hydroxyl radicals (•OH); however, in high concentrations (11.0 mg/L), its light-screening effect was dominant. In comparison, the presence of bromide (≤1.0 mg/L) inhibited H 2 O 2 formation mainly by reacting rapidly with both •OH and H 2 O 2 . Carbonate and phosphorous species exerted influence mainly by consuming •OH. Along with irradiation, increasing pH significantly decreased H 2 O 2 levels, confirming that H 2 O 2 was formed mainly by •OH. In contrast, raising DO did not raise H 2 O 2 maximum yields, confirming that reducing radicals like aqueous electrons (e - aq ) and hydrogen atoms (•H) are not the key precursors of H 2 O 2 in this process. Mathematically, the evolutions of H 2 O 2 can be reliably modeled (R 2 ≥ 0.80) using a kinetics model incorporating H 2 O 2 formation and decomposition kinetics. The results of this study may contribute to better understanding the use of VUV technology in water/wastewater treatment.
研究领域:
环境科学
·
水处理技术
✓ 已验证
DOI
PubMed
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Jing Lou,Jiutao An,Xiangyou Wang,Xiaonan Yang,Guanglu Lu,Liang Wang,Zitong Zhao
A systematic investigation of coupling dielectric barrier discharge (DBD) plasma and different ultraviolet bands (UVA, UVB, UVC, and VUV) was constructed for antibiotic-contaminant wastewater treatment . Compared with DBD, UV, or other combined DBD/UV systems, the DBD/VUV/UVC system exhibited excellent degradation and mineralization efficiencies for oxytetracycline (OTC), achieving 93.2% removal rate (reaction rate constant 1.05 min −1 ) and higher decarbonization efficiency (mineralization rate 0.47 mg C min −1 ) within 2.5 min treatment. The radical quenching tests revealed that HO⋅, O 2 · - , and 1 O 2 were all involved in the decomposition of OTC in the DBD/VUV/UVC system, among which O 2 · - played a dominant role. Possible degradation pathways of OTC in the DBD/VUV/UVC process were proposed using density functional theory and detected intermediates. Four indexes were used to assess the toxicity of OTC and its degraded intermediates. The inorganic anions and HA slightly reduced the degradation efficiency of the DBD/VUV/UVC system. This research provides new ideas to broaden the application of plasma and alleviate the water environment crisis.
研究领域:
环境科学
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水处理
·
等离子体化学
·
药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Jiayu Du,Decai Liu,Zhiyong Zhang,Huiying Ai,Ming-Lai Fu,Wenjie Sun,Baoling Yuan
The widespread use of chlorine during disinfection has led to the problems of disinfection by-products (DBPs). Recently, the combination of ultraviolet (UV, 254 nm) and vacuum ultraviolet (VUV, 185 nm) with chlorine has been considered a promising strategy to mitigate the formation of DBPs. This study systematically evaluated the efficacy of six different disinfection methods in abating humic acid (HA), a common precursor of DBPs (UV-Chlorine, VUV/UV-Chlorine, Chlorine-UV, Chlorine-VUV/UV, UV/Chlorine, and VUV/UV/Chlorine). Under 40 mJ/cm 2 UV fluence and 3 mg/L chlorine dose, the synergistic processes yielded DBP levels below 20 μg/L, whereas sequential disinfection resulted in DBP levels exceeding 100 μg/L. Additionally, there was no significant difference in the formation of DBPs between the two methods of chlorination followed by irradiation. However, for irradiation followed by chlorination, the addition of VUV led to an increase of 50 μg/L in trihalomethanes (THMs). As the irradiation time increased, the inclusion of VUV demonstrated enhanced control of DBP levels in the sequential disinfection process. Moreover, compared to UV/Chlorine, at 13 mg/L chlorine dose in VUV/UV/Chlorine process, the inclusion of VUV expedited the appearance of peak DBPs by two minutes and reduced the peak value by 25.6 %, but the DBP yield was 12.9 times higher than that at a chlorine dose of 3 mg/L. This study, comparing six combination disinfection methods, will provide deeper insights into precursor abatement and DBP control during drinking water disinfection.
研究领域:
环境科学
·
公共卫生
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2012
·Vol. 137
·期 12
·
IF 3.333
Guan Jiwen,Hu Yongjun,Zou Hao,Cao Lanlan,Liu Fuyi,Shan Xiaobin,Sheng Liusi
In present study, photoionization and dissociation of acetic acid dimers have been studied with the synchrotron vacuum ultraviolet photoionization mass spectrometry and theoretical calculations. Besides the intense signal corresponding to protonated cluster ions (CH 3 COOH) n ·H + , the feature related to the fragment ions (CH 3 COOH)H + ·COO (105 amu) via β-carbon-carbon bond cleavage is observed. By scanning photoionization efficiency spectra, appearance energies of the fragments (CH 3 COOH)·H + and (CH 3 COOH)H + ·COO are obtained. With the aid of theoretical calculations, seven fragmentation channels of acetic acid dimer cations were discussed, where five cation isomers of acetic acid dimer are involved. While four of them are found to generate the protonated species, only one of them can dissociate into a C–C bond cleavage product (CH 3 COOH)H + ·COO. After surmounting the methyl hydrogen-transfer barrier 10.84 ± 0.05 eV, the opening of dissociative channel to produce ions (CH 3 COOH) + becomes the most competitive path. When photon energy increases to 12.4 eV, we also found dimer cations can be fragmented and generate new cations (CH 3 COOH)·CH 3 CO + . Kinetics, thermodynamics, and entropy factors for these competitive dissociation pathways are discussed. The present report provides a clear picture of the photoionization and dissociation processes of the acetic acid dimer in the range of the photon energy 9–15 eV.
研究领域:
化学物理学
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光谱学
·
计算化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Zhuo-Yuan Xiao,Nan Huang,Qi Wang,Wen-Long Wang,Qian-Yuan Wu,Hong-Ying Hu
Quaternary ammonium compounds (QACs) are crucial ingredients in many cleaning agents, disinfectants and personal care products. They are widely detected in aquatic environments. In this study, vacuum ultraviolet (VUV)/UV/chlorine was used to degrade dodecyl dimethyl benzyl ammonium chloride (DDBAC, a typical QAC). The degradation efficiency of VUV/UV/chlorine on DDBAC was the highest among chlorine, UV, VUV/UV, UV/chlorine and VUV/UV/chlorine. During the VUV/UV/chlorine process, with chlorine concentration increasing from 0 to 700 μM, the degradation rate constant of DDBAC increased from 0.16 to 0.22 min −1 then decreased to 0.17 min −1 . When the chloride concentration was 10 mM and 50 mM, the degradation rate constant of DDBAC decreased by 31% and 55%, respectively. Inorganic anions and organic compounds in the reverse osmosis concentrate inhibited the degradation of DDBAC by quenching radicals. The degradation mechanisms of DDBAC degradation during the VUV/UV/chlorine process include UV photolysis and oxidation by OH, Cl and other reactive species. With the increase in pH from 5 to 10, the OH concentration decreased from 18.7 × 10 −14 M to 7.5 × 10 −14 M, and the Cl concentration decreased from 8.8 × 10 −14 M to 2.1 × 10 −14 M. At pH 5–10, contributions of OH and Cl to DDBAC degradation were 30%−44% and 18%−37%, respectively. Degradation mechanisms of DDBAC mainly include hydrogen abstraction, hydroxylation, and cleavage of the C-N bond. The concentrations of four chlorinated products (trichloromethane, monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid) mostly initially increased and then decreased.
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
CHEMOSPHERE
·
2022
·
IF 8.943
Dongxue Lei,Xiaowen Xie,Yongjie Xiang,Xiongfei Huang,Fei Xiao,Jianping Cao,Guangqing Li,Dennis Y.C. Leung,Haibao Huang
The elimination of volatile organic compounds (VOCs) via vacuum ultraviolet (VUV) photolysis is greatly limited by low removal efficiency and gaseous byproducts generation, while photocatalytic oxidation of VOCs suffers from catalytic deactivation. Herein, a coupled process of gaseous VUV photolysis with aqueous photocatalytic oxidation with P25 as the catalyst was firstly proposed for efficient aromatic VOCs removal (VUV/P25). The removal efficiency of toluene reached 86.2% in VUV/P25 process, but was only 33.6% and 58.1% in alone gaseous VUV photolysis and aqueous ultraviolet photocatalytic oxidation (UV/P25) process, respectively. Correspondingly, the outlet CO 2 concentration in VUV/P25 process reached 132 ppmv. Toluene was firstly destructed by high-energy photons generated from gaseous VUV photolysis, resulting in its incomplete oxidation to form soluble intermediates including acids, aldehydes, esters. These soluble intermediates would be further degraded and mineralized into CO 2 in subsequent aqueous UV/P25 process. Notably, the concentrations of intermediates in VUV/P25 were much lower than those in VUV photolysis, indicating the synergy effect of VUV photolysis and UV/P25 process. The stability tests proved that VUV/P25 process maintained an excellent toluene degradation performance and P25 did not suffer from catalytic deactivation. In addition to toluene, the VUV/P25 system also achieved the efficient and sustainable degradation of styrene and chlorobenzene , suggesting its good application prospect in industrial VOCs treatment. This study proposes an efficient and promising strategy for deep oxidation of multiple aromatic VOCs in industries.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Dong Wen,Wentao Li,Jinrong Lv,Zhimin Qiang,Mengkai Li
This study investigated methylene blue (MB) degradation by the vacuum-ultraviolet/ultraviolet/persulfate (VUV/UV/PS) process using a mini-fluidic VUV/UV photoreaction system. Results show that MB degradation by the VUV/UV/PS process was significantly higher than that of the conventional UV/PS process, as the VUV photolysis of H 2 O and PS generated more reactive oxygen species (ROSs). HO • and SO 4 •− , identified as the main ROSs, were mostly consumed by dissolved organic carbon and Cl ‒ in real waters, respectively. Additionally, the impacts of solution pH and the concentrations of PS, humic acid, and inorganic ions (HCO 3 ‒ , Cl ‒ , NO 3 ‒ , SO 4 2‒ , Fe(II), and Fe(III)) were systematically evaluated. The solution pH significantly affected the photon absorption distributions, as well as the contributions of photolysis and oxidation to MB degradation, resulting in different variations in the degradation rate constant and total organic carbon removal ratio with increasing solution pH. At all tested pH levels (3.0–11.0), particularly under acidic conditions, HO and SO 4 − were two predominant contributors to MB degradation, while VUV and UV photolysis contributed more when the solution pH increased. This study provides a highly efficient process for organic pollutant removal, which could be applied in water treatment.
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
危险品化学品经营许可证（带存储）