SCIENCE OF THE TOTAL ENVIRONMENT
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2021
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IF 7.963
Yongjun Huang,Zixiang He,Xiaobin Liao,Yusheng Cheng,Huan Qi
Carcinogenic N , N -Dimethylnitrosamine (NDMA) has been reported to generate significantly during ozonation of fuel additive unsymmetrical dimethylhydrazine (UDMH), the combined ozone/Peroxy-Monosulfate (O 3 /PMS) technology was tried for reducing its formation in this study. The influence of PMS dosages, ozone concentrations, pH, Br - and humic acid (HA) on NDMA formation from UDMH were investigated. In addition, the reduction mechanisms were explored by intermediates identification and Gaussian calculation. The results demonstrated that O 3 /PMS technology was effective on NDMA reduction, reaching an efficiency of 81% with 80 μM PMS. Higher NDMA reduction rates were achieved by O 3 /PMS with increasing pH within the scope of research (from 5 to 9), achieving a maximum of 69.9% at pH 9. The presence of bromide ion facilitated NDMA generation during ozonation, but the reduction efficiency by O 3 /PMS slightly improved from 66.3% to 70.6%. The presence of HA reduced NDMA formation in O 3 /PMS system. The contribution of SO 4 •− on NDMA reduction accounted for ~64%, which was higher than that of •OH (41.4%); however, its promotion role on conversing UDMH to NDMA was lower than O 3 . Therefore, the technology could reduce NDMA formation effectively. In addition, the results of Gaussian calculation manifested that the N atom in -NH 2 group of UDMH was easily attacked not only by •OH but also by O 3 , so it is the key path that determines final NDMA formation. This study would provide reference for reducing NDMA formation during ozonation of UDMH-containing water matrixes.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Menglan Gao,Zhibin Jiang,Xiaobin Liao,Xingji Bai,Huan Qi,Jing Zou,Wei Cao
Unsymmetrical dimethylhydrazine (UDMH) is found to generate substantial carcinogenic nitroso-dimethylamine (NDMA) during ozonation , moreover, its formation is promoted by ubiquitous bromide ions (Br − ) in water matrixes, but the mechanism is still unclear. In this study, effects of Br − on NDMA formation during ozonation of UDMH were studied, meanwhile, its promotion pathways were also determined. The results demonstrated that Br − promoted NDMA formation from UDMH during ozonation, the formation rate constant with Br − is over 7 times of that without Br − . NDMA amount raised from 142.5 to 327.5 μg/L when Br − dosages increased from 0 to 100 μM. No matter with or without Br − , the augment of O 3 dosages facilitated NDMA formation; the maximum value was achieved at pH 8. NDMA decreased dramatically from 173.8 to 123.5 μg/L with HCO 3 − raising from 0 to 160 μM, while increasing remarkably to 222.5 μg/L with SO 4 2− dosing. In addition, NOM inhibited NDMA formation from UDMH during ozonation. The mass spectrum of LC-MS/MS verified that the generation of Br-UDMH was main cause for promoting NDMA formation. Moreover, hypobromous acid (HBrO) was confirmed to be responsible for Br-UDMH formation. In addition, the position that oxidants and Br − attacked was demonstrated based on Gaussian calculation. The results of this study could provide theoretical basis for the application of ozonation in bromine-containing water matrixes.
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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DOI
高影响因子
Environmental Science-Water Research & Technology
·
2020
·Vol. 6
·期 10
·2766-2775
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IF 3.449
Huan Qi,Qing Lin,Mengyi Chen,Xiaobin Liao,Jie Chen,Fei Li,Baoling Yuan
Daminozide (DMNZD) has been found to be an important ozone-reactive N-nitrosodimethylamine (NDMA) precursor; however, the influence of humic acid (HA) on NDMA formation from daminozide during ozonation is unclear. In this study, the impacts of HA on NDMA formation from daminozide at various oxidation conditions (ozone dosages, pH) and other water components (bicarbonate ion (HCO3−), sulfate ion (SO42−)) were investigated. In addition, its implications for water treatment plants are discussed. The results indicated that low levels of HA (≤0.6 mg L−1) facilitated NDMA formation and its molar yield was maximized at 0.1 mg L−1 HA (8.5%), while a high concentration of HA (>0.6 mg L−1) had an inhibition role. The NDMA amount increased with increasing pH and showed a peak at pH 8. With 0.1 mg L−1 HA, NDMA was raised from 3.0% to 23.1% with ozone increasing from 0.5 to 4 mg L−1; HCO3− competed with daminozide for ozone and cut down NDMA formation, whereby 160 μM HCO3− reduced NDMA conversion from 8.5% to 6.5%; however, with the increase in SO42− from 0 to 20 μM, NDMA conversion was augmented from 8.5% to 17.8%. Based on the results of LC/MS/MS and GC/MS analyses, NDMA transformation pathways with/without HA are proposed.
研究领域:
环境科学
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化学
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DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
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IF 10.753
Menglan Gao,Zhibin Jiang,Xiaobin Liao,Huan Qi,Lei Zhao,Chao Chen,Danielle Westerman
Aliphatic amines, common constituents that contribute to dissolved organic nitrogen (DON), can quickly react with ozone due to the lone electron pair on the nitrogen atom and this may produce carcinogen N -Nitrosodimethylamine (NDMA). 3-(Dimethylamino)-1-propylamine (DMAPA) was chosen as a representative to elucidate the NDMA formation characteristics, kinetic rates, reaction pathways, and influencing factors during ozonation in this study. The results demonstrated that NDMA generated directly from DMAPA during ozonation. Moreover, the NDMA yields increased with ozone dosages. The NDMA molar yield increased and then decreased when the pH raised from 5 to 9, achieving the maximum value at pH 8. Hydroxyl radical (∙OH) played a promotional role in NDMA formation, and its scavenger dramatically cut down its yields. Low levels of Br − facilitated NDMA formation, while the value significantly reduced when Br − was up to 1 mM. The NDMA amount was slightly raised by NO 2 − , but it was inhibited by NH 4 + and NO 3 − . Moreover, it was also depressed by co-existing components in actual lake water. Based on the result of the Gaussian calculation, the LC-MS/MS and GC–MS analysis, four possible transformation pathways were proposed. The radical recombination was verified to be the primary pathway for ozone promoting NDMA formation from DMAPA.
研究领域:
环境科学
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化学
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Xiaobin Liao,Linlu Shen,Zhibin Jiang,Menglan Gao,Yu Qiu,Huan Qi,Chao Chen
Metformin, a high-consumed pharmaceutical for diabetes, has been reported to generate carcinogenic nitroso-dimethylamine (NDMA) during treatment of its containing wastewater. However, whether it would produce NDMA during ozonation or not is unclear, let alone discriminate roles of ozone (O 3 ) and hydroxyl radicals ( OH). In this paper, effects of ozonation on NDMA formation from metformin were investigated, roles of O 3 and OH were also distinguished by adding tert-butyl alcohol (tBA) as OH scavenger. Moreover, various influencing factors and reaction mechanisms were demonstrated. The results indicated that NDMA could be directly formed from metformin during ozonation, the addition of OH scavenger significantly enhanced its formation (0–46.2 ng/L vs 0–139.1 ng/L). The formation of NDMA by O 3 and OH was more affected by bromide and HCO 3 − than those with only O 3 ; while the impacts of pH and sulphate on the latter were more notable. No matter without/with tBA in the solution, the formed NDMA during ozonation of metformin increased with raising pH (from 5 to 9) and achieved the maximum 69.6 ng/L and 235.9 ng/L at pH 9, respectively; small amount of bromide (0.1 μM) promoted NDMA production, high levels of bromide (10 μM) inhibited its formation; the existence of HCO 3 − enhanced the amounts of NDMA from 44.5 to 73.5 ng/L (raised by 65.2%) by O 3 and OH and from 102.9 to 130 ng/L with only O 3 (raised by 26.3%); with the addition of sulphate, NDMA concentration raised by 43.8% by O 3 and OH, while the value was high up to 134.6% with only O 3 . Based on the result of UPLC-Q-TOF and density functional theory , the oxidation intermediates were identified and possible transformation pathways of metformin during ozonation were proposed. The findings in this paper would provide reference when treating metformin-containing water in future.
研究领域:
环境科学
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药学
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DOI
高影响因子
CHEMOSPHERE
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2020
·
IF 5.778
Beibei Zhang,Junshen Liu,Ru-Song Zhao,Qiming Xian
Nitrosamines , which are emerging nitrogenous disinfection by-products, have raised great concern owing to their carcinogenicity and genotoxicity. Thus, exploring efficient materials to remove nitrosamines from the environment is of vital importance. In this work, NaBH 4 was taken as a reducing agent and Ag-based metal organic nanotubes (Ag-MONTs) were impregnated in FeSO 4 ·7H 2 O to prepare nanoscale zero-valent iron (nZVI) supported on the nanotubes (nZVI@Ag-MONTs). The new material was then characterized and applied to N -dimethylnitrosamine (NDMA) adsorption and degradation in water. The material had excellent ability to adsorb and degrade NDMA, and the total concentrations of iron and silver remaining in water did not exceed standard limits after 120 min of adsorption. Coexisting substances, such as NO 3 − , Cl − , CO 3 2− , humic acid , trichloromethane, and trichloronitromethane, did not affect the NDMA removal efficiency of the adsorbent. The NDMA removal efficiency of the new material exceeded 88% even in the presence of SO 4 2− and PO 4 3− . The NDMA degradation mechanism of nZVI@Ag-MONTs included a catalytic hydrogenation reaction and resulted in dimethylamine as the final degradation product . The nZVI@Ag-MONTs showed favorable stability and reusability. Taking the results together, the nZVI@Ag-MONTs proposed in this work are applicable to NDMA adsorption and degradation in water.
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Menglan Gao,Xiaobin Liao,Shuting Chen,Xiaoying Li,Yirou Zhang,Chao Chen,Huan Qi
Bromide ion (Br - ) in water sources has been found to affect the formation of carcinogenic non-brominated N-nitrosodimethylamine (NDMA) during ozonation of typical amines. The increasing bromide levels bring more concern due to climate change and industrial discharge, but its effects on actual water matrixes were still unclear. In this study, NDMA formation from three actual water matrixes during ozonation as the Br - concentration increased from 0 to 100 µM were investigated (promotion (100.4 ∼ 231.6 ng/L), promotion then inhibition (399.5 ∼ 461.2 ∼ 428.2 ng/L), and subtle influence (51.9 ± 6.9 ng/L)); from which the NDMA precursors were screened and 8 precursors were selected for exploring the influencing mechanisms. The results indicated that the roles of Br - on NDMA formation significantly depended on the water characteristics of actual matrixes. A total of 16 typical NDMA precursors, which were mainly derived from industrial, agricultural and pharmaceutical sources, were identified. Moreover, 6 brominated substance (Br-DMA, Br-UDMH, Br-DMSC, Br-DMS, Br-TMDS, Br 2 -TMDS), which were thought to play a crucial role in promoting NDMA formation, were also identified in actual water by precursor ion scan (PIS) method. Hypobromous acid (HOBr), which has been proved to be the culprit to the generation of brominated substances, tend to attack the electron-donating groups of amines, such as acylamino (–NHCO-R) or amidogen (–NH 2 ) groups. However, the reactive bromine species (∙Br and ∙Br 2 - ) was inclined to attack the aromatic and anti-oxidant moieties then result in Br - release, as no bromine substitution but free radical transfer reaction occurs. Therefore, decreasing HOBr formation is the crucial step to reduce NDMA generation. This work would provide technical guide for NDMA risks control during ozonation of Br - -amines co-containing water matrixes.
研究领域:
环境科学
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化学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2022
·
IF 14.224
Menglan Gao,Xiaobin Liao,Jing Yu,Xinna Lin,Huan Qi,Linlu Shen,Shupo Liu,Zhimin Yang
Bromide ions (Br - ) affected non-brominated nitroso-dimethylamine (NDMA) formation during ozonation , but the mechanism is still unclear. 1,1,1′,1′-tetramethyl-4,4′-(methylene-di- p -phenylene) di-semicarbazide (TMDS) was chosen to further probe this problem. The results indicated that low levels of Br - (≤20 μM) enhanced NDMA from 3.27 to 7.56 μg/L, while its amount slightly dropped to 6.22 μg/L raising Br - to 100 μM. It was experimentally verified that intermediates 1,1-dimethylsemicarbazide (DMSC) and 1,1-dimethylhydrazine (UDMH) played important roles on promoting NDMA generation, whose contribution rates were 40.2% and 32.2%, respectively. The brominated substances with higher NDMA molar yields were detected. ∙OH reduced NDMA formation without Br - , while it played promotion role with Br - ; the corresponding contribution rates were − 26.9% and 29.2%, respectively. No matter with or without Br - , both ∙O 2 - and l O 2 brought a boost to NDMA formation, their contribution ratios were 34.9% and 58.1% without Br - , while raised significantly to 64.6% and 81.5% when Br - existed. Br - not only facilitated NDMA formation, but also benefited the degradation of TMDS. Based on the calculation results and intermediates detected, the influence mechanisms of Br - were proposed. The results would provide theoretical basis and technical guarantee for treating NDMA precursors and bromide co-existing water in the future.
研究领域:
环境科学
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水处理工程
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DOI
PubMed
高影响因子
Environmental Science-Water Research & Technology
·
2022
·Vol. 8
·期 6
·1252-1260
·
IF 5.819
Wei Zhang,Nan Li,Caiwen Wang,Guangchao Li,Julong Sun,Shumin Zhu
Diuron, a persistent organic herbicide, was effectively degraded by the solar/chlorine process in this study. The solar/chlorine process could not only produce HO˙ (hydroxyl radicals) and reactive chlorine species (RCS), but also O3. They are the major contributors to diuron degradation at different solution pH values (6–8). Natural organic matter (NOM), NO2− and a high dosage of Cl−, NO3−, and HCO3− could inhibit the efficiency of diuron degradation. Moreover, a possible degradation pathway of diuron was proposed, which gives detailed reactions in the solar/chlorine process. The co-existence of NO2− in diuron degradation has risks of producing N-nitrosodimethylamine (NDMA). Finally, the ecotoxicity of diuron and its oxidation byproducts was reduced overall according to the calculated results from the Ecological Structure Activity Relationships (ECOSAR) program. But the toxicity of the products is still very high. For that, the solar/chlorine process should be of concern when it is used for diuron degradation.
研究领域:
环境科学
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化学
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DOI
高影响因子
Journal of Environmental Sciences
·
2016
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IF 2.208
Xianze Wang,Zhongmou Liu,Chi Wang,Zhian Ying,Wei Fan,Wu Yang
The presence of mutagenic and carcinogenic nitrosamines in water is of great concern. In this study, seven nitrosamines including N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), N-nitrosomethylethylamine (NMEA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip), N-nitrosodi-n-propylamine (NDPA), and N-nitrosodi-n-butyl-amine (NDBA) were investigated in river water and ground water samples collected from 5 representative cities (Jilin, Songyuan, Harbin, Jiamusi and Tongjiang) along the Songhua River. The total concentrations of nitrosamines in ground water were n.d. (not detected) to 60.8 ng/L, NDMA was the most frequently detected nitrosamines in ground water, followed by NDEA and NPip. Relatively high detected frequency and concentrations of NDMA were also observed in river water samples, and the total nitrosamines' concentration at midstream is always higher than that at upstream and downstream. After 24 hr chlorination, concentration of NDMA, NDBA was obviously increased but NDEA was reduced. Furthermore, UV 254 showed a better relationship with NDMA-FP rather than dissolved organic carbon (DOC), NH 4 -N, and TDN.
研究领域:
环境科学
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公共卫生
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产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Peizeng Yang,Hailing Chu,Jiating Liu,Teng Zhang,Junhe Lu
Sulfate radical (SO 4 •− ) advanced oxidation processes (SR-AOPs) are efficient for degrading a broad spectrum of contaminants. This study demonstrates that the existence of environmentally relevant concentrations of nitrite (NO 2 − ) can lead to the formation of N -nitrosodimethylamine (NDMA), a probable human carcinogen, when heat activated peroxydisulfate (heat/PDS) is applied to address contaminants with dimethylamine moieties, such as tetracyclines. NO 2 − effectively competes with tetracyclines for SO 4 •− at a high second-order reaction rate constant of 8.8 × 10 8 M −1 s −1 , thus suppressing the degradation. Simultaneously, SO 4 •− reacts with NO 2 − to form the nitrogen dioxide radical (NO 2 • ) which rapidly dimerizes to a potent nitrosating agent named dinitrogen tetroxide (N 2 O 4 ). N 2 O 4 , in turn, attacks the dimethylamine moiety in tetracyclines via nucleophilic substitution, contributing to the degradation of parent compounds and generating an active intermediate that quickly decomposes to NDMA, along with the release of R + and NO 3 − . The released R + can be further oxidized by SO 4 •− to form phenolic intermediates which combine with NO 2 • to generate nitrated products. When 5 μM oxytetracycline (OTC) was treated with 0.5 mM PDS in the presence of 20 μM NO 2 − at 60 °C, the highest formation of NDMA was 0.045 μM in 1 h. NDMA formation was also observed for other compounds with dimethylamine moieties, such as methylene blue, phenylurea herbicides, etc., with the molar yield ranging from 0.07 to 3.53 %, negatively related to the R-N bond dissociation energy of the precursors. These findings suggest that NDMA can be commonly generated when SO 4 •− is applied to the degradation of dimethylamine pollutants in wastewater treatment or groundwater remediation where NO 2 − ubiquitously exists, which may pose a serious threat to the aquatic environment.
研究领域:
环境科学
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毒理学
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产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Linfang Li,Qing Lin,Xiaobin Liao,Tianze Liu,Huan Qi,Qingsong Li,Menglan Gao,Jing Zou,Zhenming Zhou,Mingzhi Huang,Zhimin Yang
The widespread amines have been found to generate carcinogenic nitro-dimethylamine (NDMA) during ozonation, it's urgent to search effective methods to control its formation. This work investigated the performance and mechanisms of bimetallic organic framework (MIL-100(Fe-Mn)) on reducing NDMA production during ozonation of daminozide (DMNZD). The results demonstrated that NDMA concentration raised from 27.6 to 248.4 μg/L when ozone dosages enhanced from 0.5 to 4 mg/L; while just slightly increased from 0.9 to 3.7 μg/L when MIL-100 (Fe-Mn) was added, with a reduction rate up to 98.5 %. When catalyst dosages increased from 0 to 200 mg/L, NDMA reduction rates enhanced from 54.5 to 97.4%. Moreover, neutral conditions facilitated the exploitation of MIL-100(Fe-Mn) during ozonation. Water bodies containing high concentrations of CO 3 2− , HA, and Br − should be avoided to prevent high NDMA risk. MIL-100(Fe-Mn) enhanced the transformation of ozone molecular (O 3 ) to hydroxyl radical (·OH) other than superoxide radicals (·O 2 − ) and singlet oxygen ( 1 O 2 ). EPR and scavengers quenching experiments verified that ·OH played important roles in NDMA reduction. Except ·OH, hydrogen radicals (·H) were detected in catalyzed ozonation system for the first time. The results would provide new insights for NDMA risks control during ozonation.
研究领域:
环境科学
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化学工程
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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）