JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
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2018
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IF 2.891
Jia Deng,Guangxue Wu,Shoujun Yuan,Xinmin Zhan,Wei Wang,Zhen-Hu Hu
Ciprofloxacin (CIP) is a widely used third generation fluoroquinolone antibiotics, and has been often detected in wastewater treatment plants. Finding an effective way to remove them from wastewater is of great concern. Ultraviolet (UV)/chlorine advanced oxidation process (AOP) has many advantages in micropollutant removal. In this study, CIP degradation in UV/chlorine process was investigated. Only 41.2% of CIP was degraded by UV photolysis and 30.5% by dark chlorination in 30 min, while 98.5% of CIP was degraded by UV/chlorine process in 9 min. HCO 3 − had markedly inhibition, NO 3 − and SO 4 2- had slight inhibition, and Cl − had a marginal inhibition on CIP degradation in UV/chlorine system. The degradation of CIP in UV/chlorine process was mainly attributed to the attack of reactive species. The relative contributions of hydrated electrons (e aq ), hydroxyl radicals (HO ), chlorine atoms (Cl ), and UV photolysis were investigated. Under neutral condition in aqueous solution, CIP degradation had highest pseudo first-order reaction rate constant, in which e aq had the highest contribution, followed by Cl , HO , and UV photolysis. The intermediates and byproducts were identified and the degradation pathway was proposed. The total organic chlorine (TOCl) and biotoxicity were further assessed. CIP and natural organic matters (NOMs) were removed efficiently in real water. UV/chlorine showed the potential for the wastewater treatment containing CIP.
研究领域:
环境科学
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水处理工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
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IF 3.573
Huaying Liu,Biaojun Zhang,Yingjie Li,Qi Fang,Zhichao Hou,Senlin Tian,Junjie Gu
Degradation of sulfapyridine as a representative sulfonamide by the UV/chlorine process was investigated. Kinetic experiments revealed that aniline and sulfonamide moieties were sulfapyridine’s main reaction sites with •OH, and the aniline moiety was the preferable site for Cl• attack. Effects of four influence factors (pH; humic acid, HA; HCO3–; Cl–) on the degradation kinetics were explored by response surface methodology, and it was found that pH and HA have the highest level influence (81%) among all influence variables (linear, quadratic, and interactive terms), and low pH and concentrations of HA were beneficial for degradation. Approximately 70% of sulfapyridine degradation was observed within 60 min in the UV/chlorine system (pH = 5) without HA. A kinetic model considering steady-state concentrations of reactive radicals and their second-order rate constants is suitable for predicting sulfapyridine degradation, elucidating that •OH and Cl• are major radicals for sulfapyridine degradation in freshwater, and •OH and Cl2•– are responsible for the degradation in coastal seawater.
研究领域:
环境科学
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水处理工程
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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
Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Xin Lei,Yu Lei,Shuangshuang Cheng,Xin Yang
N -nitrosamines are great concern in potable water reuse. This study investigated the reaction kinetics of chlorine radicals (Cl • and Cl 2 •− ) with N -nitrosamines. The second-order reaction rate constants of Cl • ( k Cl • ) and Cl 2 •− ( k Cl2 •− ) with eight N -nitrosamines at pH 7.0 varied in the range of (5.02 ± 0.41)–(57.1 ± 4.25) × 10 8 M −1 s −1 and (0.46 ± 0.04)–(10.6 ± 0.73) × 10 8 M −1 s −1 , respectively. The numbers of methylene groups (#−CH 2 −) showed a good positive correlation with k Cl • (R 2 = 0.71), but not with k Cl2 •− . The degradation of eight N -nitrosamines under UV/chlorine advanced oxidation process (AOP) slightly increased by 1–18% in contrast to UV irradiation alone, and Cl − in the AOPs cannot inhibit their removal. The results improved the understanding of the fate of N -nitrosamines in chlorine radical-involved AOPs.
研究领域:
环境化学
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水处理
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高级氧化过程
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DOI
高影响因子
Environmental Science-Water Research & Technology
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2022
·Vol. 8
·期 11
·2744-2760
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IF 5.819
Ziru Li,Xia Yuan,Huili Tang,Xu Jiang,Chunge Wu,Lu Zheng,Erdeng Du,Mingguo Peng
The UV/chlorine process was utilized to degrade a common quinolone, ciprofloxacin, in water. Ciprofloxacin removal was high at 92.2% in 100 s, with a first-order rate constant of 0.0026 s−1 during the process. The degradation of ciprofloxacin was found to be positively related to UV intensity and chlorine dosage and negatively related to ammonia concentration. According to FMO, MSPA, CDFT, and topological quantum chemical analysis, the N6 or N7 atoms are the most vulnerable to electrophilic or radical attacks in the piperazine ring ciprofloxacin structure, indicating the most likely reactive sites for the initial reaction. 21 degradation products were identified, including 19 products by HRMS LC–MS and 2 by GC–MS. These intermediates were mainly produced through the following three pathways: the piperazine ring's cleavage, hydroxyl addition, and defluorination reaction. Both the acute toxicity tests and ECOSAR prediction illustrated that the ecological risks cannot be effectively removed due to the production of more toxic intermediates during the degradation process.
研究领域:
环境科学
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化学工程
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药学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
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IF 13.6
Shengnan Chen,Zhiwei Zhao,Fuyi Cui,Bingyan Liu
Membrane fouling , primarily resulting from natural organic matter (NOM) widely existing in water sources, has always been a chief hindrance for the prevalent application of ultrafiltration (UF). Thus, vacuum ultraviolet (VUV)/chlorine process was proposed as a strategy for UF membrane fouling control and ultraviolet (UV)/chlorine process was used for comparison. VUV/chlorine process exhibited more excellent performance on NOM removal than UV/chlorine process. [HO•]ss and [Cl•]ss were calculated as 1.26 × 10 −13 and 3.06 × 10 −14 M, respectively, and ClO• might not exist under the conditions of 0.08 mM chlorine and 30 min VUV irradiation. [HO•]ss, [Cl•]ss and [ClO•]ss were not available and the formation of reactive radicals was unsustainable in UV/chlorine system. Moreover, VUV/chlorine pretreatment also showed better performance on the reversible and irreversible membrane fouling control than UV/chlorine pretreatment. The dominated fouling mechanism in the final stage of filtration was cake filtration. Additionally, the amount of detected disinfection by-products (DBPs) in VUV/chlorine system was significantly lower than that in UV/chlorine system. During subsequent chlorination disinfection, the yield of DBPs with VUV/chorine pretreatment was higher than that with UV/chlorine pretreatment. VUV/chlorine pretreatment could effectively control DBPs formation when the pretreatment time was extended to 120 min. In summary, VUV/chlorine system presented a most excellent performance on membrane fouling control, NOM degradation and DBPs control.
研究领域:
环境科学
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水处理工程
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产品关联
DOI
PubMed
高影响因子
Environmental Technology & Innovation
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2022
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IF 7.758
Xinran Zhang,Pengfei Ren,Jianhua Zhou,Junyi Li,Zhenxing Li,Ding Wang
This study investigated the formation of disinfection byproducts (DBPs) from a real ammonia-polluted source water treated by a pilot-scale ultraviolet (UV)/chlorine process with subsequent post-chlorination. The experimental results indicated that UV/chlorine treatment enhanced the formation of trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitriles (HANs) in post-chlorination, compared to UV or chlorine applied alone under parallel experimental conditions. DBP formation was observed to depend on pH values, chlorine doses, and reaction times. THM formation was higher at pH 9.0 than pH 6.0, while HAAs and HANs were produced more readily at pH 6.0 rather than 9.0. A higher chlorine dose led to a higher amount of DBPs formed after the treatment of UV/chlorine followed by post-chlorination. The concentration of DBPs increased with the UV/chlorine treatment time increasing from 2 to 15 s and then presented a decrease trend with the reaction time prolonging to 30 s. In addition, changes in natural organic matter (NOM) properties were evaluated using three-dimensional fluorescence spectra and parallel factor analysis (PARAFAC) UV/chlorine treatment effectively destroyed humic-like and tyrosine-like components in waters with the maximum fluorescence intensity ( FI m a x ) reduced by 51.4% and 64.6%, respectively, compared to the raw water sample. The decrease of fluorescence of waters exhibited a positive correlation with the formation of DBP-FP in UV/chlorine treatment. Overall, DBP formation from the ammonia-polluted source water caused by UV/chlorine treatment could be managed by carefully determining chlorine doses and contact times to be used in the UV/chlorine process.
研究领域:
环境科学
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公共卫生
✓ 已验证
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2020
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IF 6.551
Tao Yang,Jiamin Mai,Sisi Wu,Chunping Liu,Liuyan Tang,Zongwen Mo,Mengchen Zhang,Lin Guo,Minchao Liu,Jun Ma
Benzothiazole (BZA) and benzotriazole (BTZ) as emerging contaminants were found persistent in aquatic environments and toxic to aquatic organisms. The degradation of BZA and BTZ by UV/chlorine was systematically investigated in this study, and the results showed that BZA and BTZ can be remarkably removed by UV/chlorine compared with UV alone and dark chlorination. The radical quenching tests showed that degradation of BZA and BTZ by UV/chlorine involved the participation of reactive chlorine species (RCS), hydroxyl radical (HO·), and UV photolysis. HO· dominated BZA degradation at neutral and alkalinity, while RCS dominated BTZ degradation. The second-rate order constants for ClO· and BZA and BTZ were 2.22 × 10 8 M −1 s −1 , and 2.40 × 10 8 M −1 s −1 , respectively. Besides, the second-order rate constants for HO· and BZA and BTZ were also determined at pH 5.0, 7.0, and 9.0, respectively. The degradation efficiency of BZA by UV/chlorine was substantially promoted at acidic conditions, while the degradation efficiency of BTZ was promoted at both acidic and specific alkaline range mainly due to the reactivity of radical species and deprotonated form. The influence of Cl − was negligible, but the suppression effect of humic acid was slight during the BZA and BZT degradation by UV/chlorine. The transformation products were detected and the possible pathways were proposed. Seven disinfection by-products (DBPs) were identified both in BZA and BTZ degradation and trichloromethane was the main DBP. The toxicity assessment performed by luminescent bacteria and ECOSAR analysis indicated that the detoxification of BZA could be achieved by UV/chlorine, whereas the toxicity of BTZ was increased mainly due to the formation of intermediates. The findings from this study demonstrated UV/chlorine is likewise efficient for BZA and BTZ removal but the toxicity should be considered in the BTZ degradation.
研究领域:
环境科学
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水处理工程
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毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
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2022
·
IF 11.072
Yanan Shao,Xiaodong Li,Longbo Jiang,Xue Wei,Yanlan Zhao,Xuwu Chen,Shuai Li
UV/chlorine as an advanced oxidation process (AOPs) has been employed to treat contaminants. However, current research has primarily focused on drinking water and sewage treatment . This paper investigated the degradation of ciprofloxacin (CIP) by UV/chlorine treatment in hospital urine components that contain a higher concentration of iodine (I − ). The results indicated that the characteristic ions (HCO 3 − , SO 4 2− , and NH 4 + ) and I − in hospital urine inhibited CIP removal. In contrast, the characteristic ion, Cl − ion promoted this degradation reaction. Surprisingly, microgram levels of I − strongly inhibited CIP degradation. The characteristic ions can reduce the contribution of hydroxyl radicals (HO•) and reactive chlorine species (RCS). I − can decrease the contribution rate of HO• while slightly increasing the contribution of other radical oxidation in phosphate buffer solution (PBS) ascribed to the formation of HOI and reactive iodine species (RIS). Three degradation pathways have been proposed based on the main transformation products : hydroxylation , electron transfer , and halogen substitution. The piperazine ring of CIP was the main reactive group, and the N2, C10, C16, and C13 atoms were identified as reaction sites. Preliminary toxicity analysis suggested that the toxicity of hospital hydrolyzed urine containing iodine was higher than that of PBS.
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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毒理学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2021
·
IF 7.963
Mengge Fan,Xin Yang,Qingqing Kong,Yu Lei,Xinran Zhang,Ehsan Aghdam,Ran Yin,Chii Shang
This study systematically revealed the feasibility of the sequential ClO 2 -UV/chlorine process for micropollutant removal and disinfection byproduct (DBP) control. The results demonstrated that the sequential ClO 2 -UV/chlorine process was effective for the removal of 12 micropollutants. ClO 2 pre-treatment reduced the formation of disinfect byproducts (DBPs) in the UV/chlorine process. Compared to the UV/chlorine process, ClO 2 pre-treatment (1.0 mg L −1 ) decreased the formation of the 6 DBPs by 25.1–72.2%; and decreased the formation potential of the 6 DBPs by 13.9–51.8%. Moreover, ClO 2 pre-treatment reduced the concentration of total organic chlorine by 19.8%. ClO 2 pre-treatment affected the UV/chlorine process in different ways. Firstly, ClO 2 pre-treatment generated chlorite, which dominantly served as a scavenger of chlorine radical (Cl ) and hydroxyl radical (HO ). Secondly, ClO 2 pre-treatment decreased the reactivity of natural organic matter (NOM) towards radicals. Finally, ClO 2 pre-treatment altered the properties of NOM, in terms of reducing the electron-donating capacity and aromaticity of NOM (SUVA 254 ), and slightly reducing the average molecular weight of NOM. Overall, ClO 2 pre-treatment effectively controlled the formation of DBPs in the UV/chlorine process. This study confirmed the sequential ClO 2 -UV/chlorine process was an alternative strategy to balancing the micropollutant removal and DBP control.
研究领域:
环境科学
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水处理
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
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2023
·
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
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Baoqiang Hao,Yang Guo,Xueling Bai,Renyuan Zhang,Xiaoqing Li,Jing Li
The combined application of chlorination and UV irradiation has the potential to yield important benefits in water treatment. However, much of the fundamental chemistry that governs the behavior of UV/chlorine systems have not been well defined. Cyano-containing pesticides (CNPs) are widely used in agriculture and inevitably enter surface waters and other aquatic environments. In this study, twenty CNPs and their intermediates were investigated to evaluate the formation of disinfection byproducts under chlorination and UV/chlorine systems. It was found that UV/chlorine can significantly enhance the generation of cyanogen chloride (CNCl) and dichloroacetonitrile (DCAN) compared to chlorination alone. The CNCl and DCAN concentrations increased from an average of 0.13 and 0.12 μM during the chlorination alone to 0.85 and 0.41 μM, respectively, when UV 254 light was introduced. The maximum yields of CNCl and DCAN could reach 31.8 % and 7.7 %, respectively. Both the photo-induced • OH and • Cl played a key role in the generation of CNCl and DCAN. Additionally, higher yields of total CNX were observed in the UV/chlorine system in the presence of bromide. Similar results were obtained in the treatment of actual water samples, in which the concentrations of CNCl and DCAN increased by orders of magnitude under UV/chlorine treatment compared to the chlorination alone. The results showed that the cyano group of organic pollutants has a higher potential to be directly converted to toxic CNCl and DCAN under UV/chlorine treatment. The inclusion of this basic chemistry will deepen our understanding of UV/chorine water treatment technologies.
研究领域:
环境科学
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水处理化学
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毒理学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）