SCIENCE OF THE TOTAL ENVIRONMENT
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2019
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IF 5.589
Xiaobin Liao,Xingji Bai,Huan Qi,Fei Li,Baoling Yuan
N-nitrosodimethylamine (NDMA) has recently been discovered to generate from daminozide (DMNZD) during ozonation . Moreover, its formation is affected by the presence of bromine ion (Br − ) in water, but the mechanism is still unclear. In this study, the effect of Br − on NDMA formation from DMNZD during ozonation at various oxidation conditions (ozone dosages, pH) and distinct water parameters was studied. In addition, the transformation pathways with/without Br − were determined. The results demonstrated that low levels of Br − promoted NDMA formation from DMNZD during ozonation. When Br − dosages increased from 0 to 1 μM, the concentration of NDMA augmented from 138 to 195.5 μg/L. However, when Br − concentration raised to 100 μM, NDMA amounts dropped to 80 μg/L. Increasing pH can raise the ratio of deprotonated DMNZD no matter with or without Br − , and promote its reaction with O 3 molecular to achieve the maximum NDMA formation at pH = 7. The amounts of NDMA decreased dramatically (from 155 to 74 μg/L) when HCO 3 – dosages increased from 0 to 160 μM with 0.1 μM Br − , however, its concentration increased remarkably (from 155 to 225 μg/L) with increasing SO 4 2− (from 0 to 20 μM). Low levels of HA (0.1–0.2 mg/L) boosted NDMA formation while relatively abundant of HA (≥0.4 mg/L) suppressed its formation. In addition, the presence of NOM inhibited NDMA formation from DMNZD during ozonation no matter Br − existed or not. Based on the results of LC/MS/MS, GC/MS and IC-MS, the transformation pathways of DMNZD with/without Br − during ozonation were proposed. This study provided new insights into the role of Br − on NDMA formation from typical amine compounds during ozonation.
研究领域:
环境科学
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水处理工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2015
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IF 4.321
Lin Wang,Juan Yang,Yongmei Li,Juan Lv,Jinte Zou
Removal of chlorpheniramine in a nanoscale zero-valent iron (nZVI) induced heterogeneous Fenton system was investigated. The removal efficiency of chlorpheniramine depended on its initial concentration, initial pH, H 2 O 2 concentration and nZVI dose. Chlorpheniramine (⩽15 mg/L) was completely removed after 60 min oxidation under the following optimal conditions: initial pH = 3.0, H 2 O 2 concentration = 0.1 mM and nZVI dose = 22.4 mg/L. The degradation of chlorpheniramine fitted well with the pseudo first-order kinetics model, and the rate constants ( k obs ) were obtained ( R 2 > 0.9). Several degradation intermediates of chlorpheniramine were detected and confirmed, including 4-hydroxy-4-methyl-2-pentanone, 2-methylaminopyridine, 4-chlorophenol, 2-propionylpyridine, 2-acetylpyridine, 4-chlorophenyl-2-pyridyl ketone, dimethylamine (DMA) and N-nitrosodimethylamine (NDMA). Based on the identified intermediates, a tentative degradation pathway of chlorpheniramine in the nZVI/H 2 O 2 system was proposed. After nZVI/H 2 O 2 reaction, 52.2% of NDMA formation potential (FP) from chlorpheniramine was reduced. Therefore, nZVI as the catalyst used in the heterogeneous Fenton system is not only an alternative to remove chlorpheniramine, but also effective in reducing NDMA FP.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
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2017
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IF 5.715
Yuanan Hu,Yuanzhen He,Hefa Cheng
N -nitrosodimethylamine (NDMA), a highly toxic and carcinogenic disinfection byproduct , cannot be efficiently removed by conventional water treatment processes , while sorption by microporous minerals, followed by destruction with microwave irradiation has been developed as a promising alternative. This work examined the impact of surface cation density and type on sorption of NDMA on dealuminated ZSM-5 zeolites , and on microwave-induced degradation of the sorbed NDMA, as well as the non-thermal effect of microwave. NDMA sorption was found to increase with the framework Si/Al ratio of dealuminated ZSM-5 zeolites (i.e., decreasing density of surface cations), and was also influenced by the type of surface cations. Degradation of the sorbed NDMA proceeded faster with increases in the power level of microwave and in the micropores with higher densities of surface cations, which was attributed to the increases in the number and/or temperature of micro-scale “hot spots” formed by microwave dielectric superheating of the surface cations. The degradation rate of sorbed NDMA was also found to be inversely correlated with the hydration free energy of surface cations present in the zeolite micropores . The apparent activation energy estimated from the temperature dependence of NDMA degradation in the micropores under microwave irradiation was 18.2 kJ/mol, which is much lower than those of typical thermolysis reactions and is indicative of significant contribution from the non-thermal effect of microwave.
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
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Haiyan Wang,Peizeng Yang,Yiqian Song,Deyang Kong,Junhe Lu
UV-based treatment technologies have been widely applied in wastewater treatment plants due to its high efficiency in deactivating pathogens and degrading organic contaminants. However, this study demonstrates that N -nitrosodimethylamine (NDMA), a probable human carcinogen, can be generated during UV treatment of dimethylamine (DMA) pollutants of concern, for example isoproturon (IPU), in the presence of nitrite (NO 2 – ). Quenching tests have identified that in addition to direct photolysis, hydroxyl radicals (HO • ) and nitrogen oxide radicals (NO • and NO 2 • ) generated from NO 2 – photolysis play a crucial role in the reaction. They can react with IPU, leading to hydroxylated and nitrated products. More importantly, NO 2 • couples with a NO • or another NO 2 • to form N 2 O 3 and N 2 O 4 , respectively. As nitrosating agents, N 2 O 3 and N 2 O 4 directly attack the released DMA during IPU degradation, yielding NDMA. At IPU initial concentration of 50 μM, the highest concentration of NDMA was 5.62 μg/L in 2.5 h by UV/NO 2 – , corresponding to the molar yield of 0.22%. This study further reveals that other dimethylamine compounds, such as diuron, imipramine, and tetracyclines, can also serve as NDMA precursors during UV disinfection with NO 2 – present. Given that many environmental contaminants contain DMA moieties and NO 2 – is ubiquitously present in wastewaters, formation of NDMA during UV disinfection is probably a common but overlooked problem, which deserves emerging concern.
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
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IF 7.963
Chenglin Liu,Zhijie Liang,Adeyemi Adeleye,Fuyi Cui,Zhiwei Zhao
N -nitrosodimethylamine (NDMA), a nitrosamine , is a typical nitrogenous disinfection byproduct . In this study, NDMA formation potential and mechanism, from tetracycline and oxytetracycline (as model precursors) in an ammonium-contaminating water, were investigated. The results indicated that both monochloramine and dichloramine played a vital role in NDMA formation. Additionally, the determination of NDMA formation potential (NDMA FP) at a wide range of pH showed that the unprotonated tetracycline tended to have a higher NDMA conversion ratio. We also found that the dissociation of hydroxyl on the meta-position of dimethylamine group promoted on NDMA formation. The detection of significant intermediate products showed that N-chloro unsymmetrical dimethylhydrazine (UDMH-Cl) and sequences of chlorine substitution products were key intermediates, indicating that NDMA formation occurred via the UDMH mechanism pathway. These results improve the knowledge on NDMA formation mechanism and the control strategies during the disinfection of ammonium-containing water.
研究领域:
环境科学
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公共卫生
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2025
·
IF 7.7
Zhenjie Zheng,Jingxuan Wang,Mengqi Ma,Yunpeng Xu,Da Huang,Jian Wang,Cuiying Lin,Zhenyu Lin,Fang Luo
Sensitive and selective detection of N -nitrosodimethylamine (NDMA), a highly carcinogenic environmental contaminant, is essential for public health and safety. In this study, we have developed a homogeneous electrochemiluminescence (ECL) biosensor for ultrasensitive NDMA detection by integrating Nafion-functionalized covalent organic framework (COF) with aptamer recognition and magnetic separation. The imine-linked COF (COF-LZU1) scaffold not only enables stable encapsulation of Ru(bpy) 3 2 + , but also creates a confined microporous environment that locally concentrates c (TPrA) and enhances the generation and survival of TPrA radicals, thereby amplifying the ECL signal. Nafion further improves Ru loading and ionic conductivity. Biotinylated aptamers were initially immobilized on streptavidin-coated magnetic beads (MBs) and hybridized with complementary DNA-modified Ru@COF-LZU1 to form Ru@COF-LZU1-MBs complex. Upon NDMA binding, a conformational switch releases Ru@COF-LZU1 into the solution. After magnetic separation, the ECL signal of the supernatant is measured in the presence of TPrA. This homogeneous format avoids electrode surface modification, which is commonly required in conventional Ru@COF-LZU1-based ECL sensors, offering improved reproducibility and simplified operation. The biosensor exhibits a wide linear range (100 fg/mL - 100 ng/mL) with a low detection limit of 9.11 fg/mL. This platform offers a sensitive, reproducible, and facile strategy for monitoring NDMA and similar small-molecule contaminants in complex matrices.
研究领域:
环境监测
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分析化学
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生物传感技术
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纳米材料
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电化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2016
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IF 3.698
Ying Han,Zhong-lin Chen,Ji-min Shen,Ji-he Wang,Wei-wei Li,Jun Li,Bin-yuan Wang,Li-na Tong
The role of Cu(II) in the reduction of N -nitrosodimethylamine (NDMA) with zero-valent metals was investigated by determining the effects of Cu(II) on the removal, kinetics, products, and mechanism. NDMA removal was enhanced, and all reactions followed a pseudo-first-order kinetic model except for the Fe and Fe/0.1 mM Cu(II) systems. The iron mass-normalized pseudo-first-order rate constants ( k MFe ) increased with the Cu(II) concentration. The zinc mass-normalized pseudo-first-order rate constants ( k MZn ) were identical to those with the Cu(II) concentrations from 0.1 mM to 1.0 mM and were higher with 2.0 mM Cu(II). The types of products detected were unchanged. Some unknown products were also found. NDMA was reduced to 1,1-dimethylhydrazine (unsymmetrical dimethylhydrazine , UDMH). Then, UDMH was reduced into dimethylamine (DMA) by the Fe/Cu(II) and Zn/Cu(II) systems. Catalytic hydrogenation was proposed as the reduction mechanism. Several copper species, such as Cu(OH) 2 in the Fe/Cu(II) system and Cu 2 O and Cu(OH) 2 in the Zn/Cu(II) system enhanced NDMA reduction. Differences between the Fe/Cu(II) and Zn/Cu(II) systems were caused by the reduction potentials and surface conditions of the different metals and the copper species in the various systems.
研究领域:
环境化学
·
水处理
·
催化
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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