Journal of Environmental Sciences
·
2022
·
IF 6.796
Shuang Zhang,Yi-Li Lin,Tian-Yang Zhang,Chen-Yan Hu,Zhi Liu,Zheng-Yu Dong,Meng-Yuan Xu,Bin Xu
In this study, the formation of iodinated trihalomethanes (I-THMs) was systematically evaluated and compared for three treatment processes - (i) chlorination, (ii) monochloramine, and (iii) dichloramination - under different pH conditions. The results demonstrated that I-THM formation decreased in the order of monochloramination > dichloramination > chlorination in acidic and neutral pH. However, the generation of I-THMs increased in the dichloramination < chlorination < monochloramination order in alkaline condition. Specifically, the formation of I-THMs increased as pH increased from 5 to 9 during chlorination and monochloramination processes, while the maximum I-THM formation occurred at pH 7 during dichloramination. The discrepancy could be mainly related to the stability of the three chlor (am) ine disinfectants at different pH conditions. Moreover, in order to gain a thorough insight into the mechanisms of I-THM formation during dichloramination, further investigation was conducted on the influencing factors of DOC concentration and Br − /I − molar ratio. I-THM formation exhibited an increasing and then decreasing trend as the concentration of DOC increased from 1 to 7 mg-C/L, while the yield of I-THMs increased with increasing Br − /I − molar ratio from 5:0 to 5:10. During the three processes mentioned above, similar I-THM formation results were also obtained in real water, which indicates that the excessive generation of I-THMs should be paid special attention during the disinfection of iodide-containing water.
研究领域:
环境科学
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水处理工程
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PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Yi-Hsueh Chuang,Chia-Shun Chou,Yi-Lin Chu
Chlorination of ammonia or chloramine-containing waters induces breakpoint chlorination reactions, producing a hydroxyl radical (•OH), but enhances the formation of undesirable N-nitrosamines. The prevailing view attributes •OH formation to a nitrosyl intermediate derived from the hydrolysis of dichloramine, but this pathway is unlikely at neutral or acidic pH. This study reveals a novel mechanism where •OH is generated via interactions between trichloramine (NCl3) and dichloramine (NHCl2), which also form nitrosation agents. Our experiments demonstrated that the NCl3–NHCl2 interaction degrades micropollutants with kinetics 2–3 times faster than breakpoint chlorination. Using electron paramagnetic resonance, we detected •OH in the NCl3–NHCl2 reaction. Micropollutant removal was unimpaired under low dissolved oxygen (O2(aq)) conditions, aligning with negligible O2(aq) changes during the NCl3–NHCl2 reaction and suggesting O2(aq) does not participate in •OH formation. Using benzene as a probe in 18O-labeled H2O, we confirmed water contributes to the oxygen source of •OH in NCl3–NHCl2 interactions, through which parallel reactions occur, leading to the formation of one mole of •OH alongside 1.92 mol of N2. A kinetic model developed in this study accurately predicted •OH and N2 and demonstrated the NCl3–NHCl2 interaction as the primary pathway for •OH formation in breakpoint chlorination, providing new insights into breakpoint chemistry.
研究领域:
环境科学
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化学工程
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PubMed
高影响因子
WATER RESEARCH
·
2019
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IF 7.913
Xinran Zhang,Pengfei Ren,Weiguang Li,Yu Lei,Xin Yang,Ernest R. Blatchley
The presence of ammonium (NH 4 + ) in drinking water treatment results in inhibition of disinfection efficiency and formation of nitrogenous disinfection by-products. Our previous study found monochloramine (NH 2 Cl) photolysis under 254 nm UV irradiation can be effective for removal of NH 4 + ; however, the mechanisms of NH 4 + degradation in this process were unknown. The kinetics and fundamental radical chemistry responsible for NH 4 + removal in the UV/NH 2 Cl process were investigated in this study. The results showed that the pseudo first-order rate constant for NH 4 + degradation in the UV/NH 2 Cl process ranged between 3.6 × 10 −4 to 1.8 × 10 −3 s −1 . Solution pH affected radical conversion and a higher NH 4 + degradation efficiency was achieved under acidic conditions. The effects of chloride were limited; however, the presence of either bicarbonate or natural organic matter scavenged radicals and inhibited NH 4 + removal. NH 2 Cl photolysis generated an aminyl radical (NH 2 • ) and a chlorine radical (Cl • ) that further transformed to a chlorine dimer (Cl 2 •- ) and a hydroxyl radical (HO • ). The second-order rate constants for Cl • and Cl 2 •- reacting with NH 4 + were estimated as 2.59 × 10 8 M −1 s −1 and 3.45 × 10 5 M −1 s −1 at pH 3.9, respectively. Cl • , Cl 2 •- , and HO • contributed 95.2%, 3.5%, and 1.3% to NH 4 + removal, respectively, at the condition of 3 mM NH 2 Cl and pH 7.5. Major products included nitrite and nitrate, possibly accompanied by nitrogen-containing gases. This investigation provides insight into the photochemistry of NH 4 + degradation in the UV/NH 2 Cl process and offers an alternative method for drinking water production.
研究领域:
环境科学
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饮用水处理
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高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
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IF 9.8
Tianze Liu,Xiaobin Liao,Xinna Lin,Jing Yu,Huan Qi,Zhibin Jiang,Jing Zou,Qingsong Li
This study was to evaluate the feasibility of controlling carcinogenic nitrosodiethylamine (NDEA) formation from greenhouse gas adsorbent 3-diethylaminopropylamine (DEAPA) by pre-O 3 in subsequent chlorination/chloramination processes. The result indicated that the NDEA yields (0.4 %) during chlorination was 1.3 times of that during chloramination (0.3 %); pre-oxidation with 4 mg/L O 3 significantly cut down its formation; the reduction rates were up to 67.5 and 48.5 %, respectively. OH scavenger greatly augmented the final NDEA amount from 1.86 to 5.05 μg/L during ozonation , while its roles on subsequent processes differed with disinfection methods as well as O 3 (g) dosages. Most of co-existed substances inhibited NDEA generation, except NO 2 − , CO 3 2− and SO 4 2− , which slightly promoted during ozonation. Basing on Gaussian calculation, GC/MS and UPLC-Q-TOF-MS analysis, the influencing mechanisms of pre-O 3 on NDEA formation in subsequent disinfection processes were proposed. In addition, the calculated toxicity analysis as well as the whole toxicity was applied to evaluate the possibility of pre-O 3 on risk control.
研究领域:
环境科学
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水处理工程
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毒理学
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PubMed
高影响因子
FORENSIC SCIENCE INTERNATIONAL
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2014
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IF 2.115
Binling Zhu,Liang Meng,Kefang Zheng
Recently a new type of mixed drug oral solution has become prevalent in China, the identification and quantitative inspection of which are demanded in conviction and sentencing as well as drug intelligence. In 2013, inspection was carried out on 86 bottles of substances seized in 13 cases with the adoption of GC–MS methodology for qualitative identification and GC–FID for quantitative identification. 94.1% of the samples were light yellow turbid liquid while 95.3% were detected with more than two drugs. Detection rate of methamphetamine, MDMA and ketamine was up to 89.5%, 37.2% and 83.7% respectively. Quantitative inspection results indicated that concentrations of methamphetamine, MDMA , ketamine were 0.04–13 mg/mL, 0.04–29 mg/mL and 0.1–34 mg/mL, respectively. Appearance, composition and drug concentration of samples vary from case to case.
研究领域:
毒理学
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分析化学
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法医学
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高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2025
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IF 11.3
Jiacheng Ge,Xiaoyan Chen,Zhenqi Du,Yingying Zhou,Ruixin Qu,Jiangdong Cui,Shunke Ding,Wenhai Chu
Halogenated nitrophenols (HNPs) have raised significant concerns due to their extensive detection and potent toxicity. Understanding how these compounds persist and degrade over time is crucial for predicting their potential accumulation and assessing the long-term exposure risks. Kinetic studies showed that the degradation of HNPs through hydrolysis and chloramination over realistic hydraulic retention times is relatively low. The species-specific second-order rate constants for the reaction of hypochlorous acid and the acid-catalyzed reaction of hypochlorous acid with anionic HNP species, which accounted for HNP degradation during chlorination, range from 3.84 ± 1.09–363.25 ± 50.44 M⁻¹min⁻¹ and from (1.50 ± 0.091) × 10⁶ to (1.34 ± 0.36) × 10⁸ M⁻²min⁻¹ , respectively. The reactivity order of reactive species in hydrolysis, chlorination, and chloramination with HNP species has also been verified through computational modeling using density functional theory. The introduction of nitro group onto HNPs significantly diminishes the electron density of the benzene ring, thereby reducing their inherent reactivity compared with other aromatic DBPs. The hydrolysis and chlorination of HNPs primarily result in the formation of halogenated hydroquinones and various polyhaloquinones and polyhalophenols, respectively. These results suggest that HNPs and their transformation products exhibit relatively high persistence and exposure risks.
研究领域:
环境科学
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饮用水安全
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毒理学
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PubMed
高影响因子
CELLULOSE
·
2024
·Vol. 31
·期 8
·5263-5280
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IF 4.9
Han Qiuxia,Xu Yanmeng,Zhao Qian,Wang Shiwei,Zhang Chunzhe,Zhang Qiang,Wang Fei,Bai Yu,Chen Yong
The study reports a tactic for superior antibacterial performance on cotton via synergism of complementary functionalities of quaternary ammonium salt and malonylurea-based N -chloramine combined in a silane. Knoevenagel Condensation between 4-(chloromethyl)benzaldehyde and malonylurea formed a product whose chloromethyl group was used to quaternize tertiary amine of N , N -dimethylethanolamine. The O − H of the quaternization product was subsequently alcoholyzed with Si − H of trimethoxysilane. The methoxysilyl groups of the alcoholysis silane were hydrolyzed to silanol ones that condensed with either their own kind or hydroxy groups of cellulose to polymerize into a crosslinked polysiloxane finishing on cotton. Upon chlorination of malonylurea-based N − H bonds, each repeating unit of the polysiloxane has one quaternary ammonium salt and two imide N -chloramine sites. Antibacterial assays against Staphylococcus aureus and Escherichia coli proved that the synergism of quaternary ammonium salt and N -chloramine, a higher efficacy and a broader spectrum arising from their complementary elimination mechanisms and physiochemical features. Biocidal stability and rechargeability of the polysiloxane finishing were both promising due to the robust and hydrophobicity of silicone backbone and the sturdy cyclic N -chloramine. This research presented a general approach for generation of super biocidability on substrates that can react with hydroxy group using silanes to carry complementary functionalities. Graphical abstract
研究领域:
材料科学
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纺织工程
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生物医学
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高影响因子
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
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2025
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IF 3.1
Zihe Yang,Linjie Li,Bin Deng,Yusen Xu,Yujing Du,Yongning Lv,Xuejia Zhai
Major depressive disorder is a severe mental condition characterized by abnormalities in the structure and function of the brain. Ketamine is a novel antidepressant that has rapid effects on depression. This drug is clinically used to treat depression in patients with acute suicidal ideation or behavior. It is typically administered at a dose of 84 mg. However, the distribution of ketamine in the body after intranasal administration, particularly in the brain, remains unknown. In the present study, we utilized a high-performance liquid chromatography-tandem mass spectrometry method to measure ketamine concentrations in rat plasma and several tissues. The measurement ranges were 5–8000 ng/mL for the plasma samples and 5–5000 ng/mL for the tissue samples. The pharmacokinetic profile revealed that the rat plasma ketamine concentration rapidly spiked to a peak of 8002 ng/mL within about 5 min, followed by a rapid decline, nearly reaching 0 ng/mL by about 3 h; the half-life was 27 min. Tissue distribution results revealed that ketamine concentrations in different tissues peaked at 5 min. The highest concentration was noted in the kidneys, followed by the liver. In the rat brain regions, ketamine was primarily concentrated in the hypothalamus and hippocampus, with lower concentrations in the striatum and prefrontal cortex. Our novel methodological approach and findings provide a significant theoretical foundation for using ketamine in clinical settings.
研究领域:
药理学
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神经科学
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PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Rui Yu,Yunkun Qian,Yanan Chen,Yijun Shi,Jun Guo,Dong An
Dichloroacetonitrile (DCAN) is an emerging disinfection by-product (DBP) that is widespread in drinking water. However, the pathway for DCAN formation from aromatic amino acids remains unclear, leading to a lack of an understanding of its explicit fate during chloramination. In this study, we investigated the specific formation mechanism of DCAN during the chloramination of phenylalanine based on reaction kinetics and chemical thermodynamics. The reason for differences between aldehyde and decarboxylation pathways was explained, and kinetic parameters of the pathways were obtained through quantum chemistry calculations. The results showed that the reaction rate constant of the rate-limiting step of the aldehyde pathway with 1.9 × 10 −11 s −1 was significantly higher than that of decarboxylation (3.6 × 10 −16 s −1 M −1 ), suggesting that the aldehyde pathway is the main reaction pathway for DCAN formation during the chloramination of phenylalanine to produce DCAN. Subsequently, theoretical calculations were performed to elucidate the effect of pH on the formation mechanism, which aligned well with the experimental results. Dehydrohalogenation was found to be the rate-limiting step under acidic conditions with reaction rate constants higher than those of the rate-limiting step (expulsion of amines) under neutral conditions, increasing the rate of DCAN formation. This study highlights the differences in DCAN formation between the decarboxylation and aldehyde pathways during the chloramination of precursors at both molecular and kinetic levels, contributing to a comprehensive understanding of the reaction mechanisms by which aromatic free amino acids generate DCAN.
研究领域:
环境科学
·
化学
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PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2019
·
IF 5.589
Jing Liu,Jing Wang,Jie Zhang,Yang Mu
In this study, the impact of Cu 2+ on the formation of iodo-trihalomethanes (I-THMs) during chlorination and chloramination of iodide-containing waters was investigated. Initially, the oxidant consumption and evolution of hypoiodous acid (HOI) were determined during disinfection in the presence of Cu 2+ and the interaction between natural organic matter humic acid (HA) and Cu 2+ was also analyzed. Subsequently, the formation of the I-THMs at various Cu 2+ concentrations was evaluated for chlorination and chloramination. Moreover, in order to explore the possible underlying mechanisms, five model compounds based on the HA structure were used to investigate the I-THMs formation with and without Cu 2+ during disinfection. The results indicated that the presence of Cu 2+ markedly affected the conformation of the HA rather than the HOI evolution during disinfection. The concentration of the I-THMs decreased from 34.5 ± 0.8 to 20.9 ± 0.8 nM as the Cu 2+ concentration increased from 0 to 20 μM during chlorination. In contrast, during chloramination, the total I-THMs concentration decreased from 320.7 ± 7.4 to 267.2 ± 10.7 nM as the Cu 2+ concentration increased from 0 to 5 μM and then increased to 315.0 ± 1.7 nM when the Cu 2+ concentration reached 20 μM. The disinfection experiments with the model compounds suggested that the impact of Cu 2+ on the I-THMs formation largely depended on the organic structures in the HA, thus leading to different results during chlorination and chloramination.
研究领域:
环境科学
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水处理工程
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PubMed
高影响因子
JOURNAL OF CHROMATOGRAPHY A
·
2012
·
IF 4.531
Kaoqi Lian,Pingping Zhang,Lingmei Niu,Siyuan Bi,Shipeng Liu,Lingling Jiang,Weijun Kang
A new method was developed for determination of ketamine (KT) in urine and plasma samples by derivatization and gas chromatography–mass spectrometry. In this article, KT was first derivatized with sodium nitrite to volatile N-nitrosamines under acidic condition. Then the derivative had been identified by the mass spectra. The derivatization conditions including the amount of hydrochloric acid, the amount of sodium nitrite, reaction temperature, reaction time and the extraction reagents were optimized. Calibration curves were linear in the range of 0.04–20 μg mL −1 for KT, and the limit of detection (LOD) and limit of quantitation (LOQ) were 0.01 μg mL −1 and 0.04 μg mL −1 , respectively. The results of recovery indicated that the method had good precision and reproducibility. Compared with existing derivatization methods, this method provided a rapid, convenient, effective and low-cost way for gas chromatography method of KT quantification.
研究领域:
分析化学
·
医学检验
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DOI
PubMed
高影响因子
Environmental Science and Ecotechnology
·
2024
·
IF 14
Zhenglu Wang,Jindong Xu,Wei Du
The coexistence of caffeine (CF) and ketamine (KET) in surface waters across Asia has been widely reported. Previous studies have implied that CF and KET may share a mechanism of action. However, the combined toxicity of these two chemicals on aquatic organisms remains unclear at environmental levels, and the underlying mechanisms are not well understood. Here we demonstrate that KET antagonizes the adverse effects of CF on zebrafish larvae by modulating the gamma-aminobutyric acid (GABA)ergic synapse pathway. Specifically, KET (10–250 ng L −1 ) ameliorates the locomotor hyperactivity and impaired circadian rhythms in zebrafish larvae induced by 2 mg L −1 of CF, showing a dose-dependent relationship. Additionally, the developmental abnormalities in zebrafish larvae exposed to CF are mitigated by KET, with an incidence rate reduced from 26.7% to 6.7%. The competition between CF and KET for binding sites on the GABA-A receptor ( in situ and in silico ) elucidates the antagonistic interactions between the two chemicals. Following a seven-day recovery period, the adverse outcomes of CF exposure persist in the fish, whereas the changes observed in the CF + KET groups are significantly alleviated, especially with KET at 10 ng L −1 . Based on these results, it is imperative to further assess the environmental risks associated with CF and KET co-pollution. This pilot study underscores the utility of systems toxicology approaches in estimating the combined toxicity of environmental chemicals on aquatic organisms. Moreover, the nighttime behavioral functions of fish could serve as a sensitive biomarker for evaluating the toxicity of psychoactive substances.
研究领域:
生态毒理学
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神经生物学
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环境科学
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PubMed
高影响因子
危险品化学品经营许可证（带存储）