ACS ES&T Water
·
2023
·
IF 5.3
Peizeng Yang,Jiayue Dong,Haiyan Wang,Teng Zhang,Gregory V. Korshin,Junhe Lu
N-Nitrosodimethylamine (NDMA) is a disinfection byproduct and a probable human carcinogen formed during water treatment processes. While its generation in engineered systems has been extensively explored, its formation in natural environments is inadequately understood. This study demonstrates that compounds with dimethylamine (DMA) functionality exposed to sunlight irradiation in the presence of nitrite (NO2–) react to form NDMA. The molar yields of NDMA ranged from 0.006 to 0.035% after 6 h irradiation. The radicals generated by the photolysis of NO2–, notably •OH, NO•, and NO2•, play critical roles in this process. Three reaction pathways are involved in the NDMA formation. In the first and second pathways, nitrogen oxide radicals couple or dimerize to form the nitrosating agents N2O3 and N2O4, which attack the DMA moiety, yielding NDMA. In the third pathway, the DMA moiety is oxidized by •OH via H-abstraction to produce a nitrogen-centered radical (CH3N•CH3) which, followed by the addition of a NO•, yields NDMA. Radical quenching experiments combined with theoretical calculations suggest that the •OH/H-abstraction pathway is more favorable. Given that many environmental contaminants contain DMA functionalities, the photochemical formation pathway of NDMA in the sunlit surface waters may be important for aquatic environments.
研究领域:
环境科学
·
公共卫生
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Ting Zhang,Weitao Wang,Meng He,Huan Wang,Zhen-Hong He,Yang Yang,Kuan Wang,Zhao-Tie Liu
Imines as valuable chemical intermediates can be synthesized by aerobic photocatalytic oxidation of amines, which is recognized as a promising and green route for imines synthesis. It is attractive to develop solvent-free photocatalytic oxidation of amines with high efficiency, especially with high activity and selectivity, but it is challenging. In the present work, flower-like BiOX/TiO 2 (X = Cl, Br, I) heterojunction was designed for solvent-free photocatalytic oxidation of benzylamine to N-benzylidenebenzylamine. Type II heterojunction of BiOCl/TiO 2 with 67.3 wt% of BiOCl achieved the high formation rate of 6316 µmol∙g −1 ∙h −1 and selectivity of 99 % on BiOCl/TiO 2 . To the best of our knowledge, the activity and selectivity are the highest for solvent-free photocatalytic system. The reason for the varied photocatalytic performances were investigated. The solvent-free photocatalytic mechanism was revealed and proposed. Moreover, the BiOCl/TiO 2 photocatalyst can be used for photocatalytic oxidation of varied benzylamines to imines.
研究领域:
化学工程
·
环境科学
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DOI
高影响因子
Solar RRL
·
2021
·Vol. 5
·期 8
·2100274
·
IF 8.582
Jian Liu,Dongjie Wang,Yang Zhang,Kun Chen,Bin She,Baichen Liu,Zheling Zhang,Yu Huang,Jian Xiong,Hailiang Zhang,Jian Zhang
Methylamine (MA) and methylamine hydrochloride (MACl) are widely used to prepare highly efficient and stable perovskite solar cells (PSCs). However, MA, as a gas, is difficult to handle and inevitably leads to a large amount of escape, and it is difficult to quantitatively calculate. Herein, selecting a mixture solvent of methylamine ethanol solution (MA-EtOH sol) and acetonitrile (ACN) as a solvent, a new strategy for preparing fully printed mesoscopic perovskite solar cells (MPSCs) at room temperature is first proposed. With the introduction of 20 mol% MACl as additive, the fully printed MPSCs are fabricated without any posttreatment at room temperature via a one-step drop-coating method. As a consequence, the average power conversion efficiency (PCE) of 14.73 ± 0.3% (0.1 cm 2 ) with almost no hysteresis is achieved. Most importantly, the device also exhibits excellent long-term stability when it is unencapsulated. Specifically, the unencapsulated device still retains nearly 100% of its original PCE after 64 days and 88% after 81 days of storage in the dark with a humidity of 50 ± 5% in an atmospheric environment. It provides a new idea for constructing fully printed MPSCs at room temperature in the future.
研究领域:
材料科学
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能源技术
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DOI
高影响因子
JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS
·
2022
·
IF 3.571
Gugu Hao,Rong Hu,Xiaoqin Wang,Pan Gao,Lin Wang,Manhua Jiang,Libo Xin,Guoying Tan,Yanping Zhao,Fuzhou Sun,Dexin Chu,Jinqian Lv,Jinsong You,Fangfang Huang,Xuezhi Song
In recent years, nitrosamines have been discovered in some types of drug products that becomes a current regulatory hotspot, and have attracted a lot attention from both regulatory authorities and industry. This manuscript provided an industry perspective on the nitrosamines research. A liquid chromatography coupled with tandem mass spectrometry（LC-MS/MS）method was developed and applied for the quantification of N-nitrosodimethylamine (NDMA) in metformin hydrochloride sustained-release tablets (MET). The key factors resulting in the NDMA formation in MET were identified through forced degradation and drug-excipient studies, which included high temperature, dimethylamine , strong alkali and oxidation conditions, peroxide and alkaline components contained in the formulation as well as the nitrite and nitrate impurities that might be presented in certain excipients. Further, API particle size and water content of the drug product would also affect the growth rate of NDMA. Therefore, the following mitigation strategies to reduce the risk of nitrosamines in the finished drug product are proposed in this manuscript: 1) avoid the use of excipients containing nitrite, nitrate and peroxide impurities; 2) avoid high temperature and strong alkaline environment in the production and storage condition; 3) maintain an appropriate water content level in the formulation. Based on the above principles, it was recommended to add antioxidant or incorporate excipient such as Na 2 CO 3 to modify the formulation pH to weak basic environment in the formulation of MET, which can could effectively prevent formation of NDMA in the stability process.
研究领域:
药学
·
分析化学
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DOI
PubMed
高影响因子
Food Analytical Methods
·
2024
·Vol. 17
·期 5
·689-700
·
IF 2.6
He Hongmei,Wang Luwei,Huang Hui,Li Yongxin
In this study, a novel gallic acid-based anthocyanin electrospun sensor was developed to monitor the freshness of the shrimp. “The sensor contains blueberry anthocyanin as indicator dye, polyacrylonitrile as polymer, and gallic acid as copigment. The sensor was studied by SEM, FT-IR, color stability, and its response to dimethylamine and trimethylamine. The results showed that the anthocyanin electrospun sensor was copigmented with gallic acid, which improved the color stability during storage (Δ E <5) and sensitivity to dimethylamine and trimethylamine. The color changes were obvious by the naked eye, which proved that the anthocyanin-gallic of the anthocyanin-gallic acid electrospun sensor during shrimp storage over 5 days at 4 °C was positively correlated with the contents of TVB-N ( R 2 = 0.9905) and pH ( R 2 = 0.9906). The color of the sensors ranged from pink to purple to yellow, and they represented the freshness, medium freshness, and spoilage of shrimp. The color changes are obvious to the naked eye. The indicated membrane had good application value in the nondestructive testing of shrimp, as the anthocyanin-gallic acid sensor could evaluate the freshness of the shrimp. This membrane demonstrates significant potential for nondestructive testing of shrimp freshness. The combination of electrospun technology and copigmentation provided a new idea for detecting the freshness of food.
研究领域:
食品科学
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传感器技术
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高分子科学
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分析化学
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食品安全
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DOI
高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Yuandong Lin,Ji Ma,Da-Wen Sun,Jun-Hu Cheng,Chenyue Zhou
A fluorescent sensor array (FSA) combined with deep learning (DL) techniques was developed for meat freshness real-time monitoring from development to deployment. The array was made up of copper metal nanoclusters (CuNCs) and fluorescent dyes, having a good ability in the quantitative and qualitative detection of ammonia, dimethylamine, and trimethylamine gases with a low limit of detection (as low as 131.56 ppb) in range of 5 ∼ 1000 ppm and visually monitoring the freshness of various meats stored at 4 °C. Moreover, SqueezeNet was applied to automatically identify the fresh level of meat based on FSA images with high accuracy (98.17 %) and further deployed in various production environments such as personal computers, mobile devices, and websites by using open neural network exchange (ONNX) technique. The entire meat freshness recognition process only takes 5 ∼ 7 s. Furthermore, gradient-weighted class activation mapping (Grad-CAM) and uniform manifold approximation and projection (UMAP) explanatory algorithms were used to improve the interpretability and transparency of SqueezeNet. Thus, this study shows a new idea for FSA assisted with DL in meat freshness intelligent monitoring from development to deployment.
研究领域:
食品科学
·
化学传感
·
人工智能
·
机器学习
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生物技术
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产品关联
DOI
PubMed
高影响因子
Micromachines
·
2022
·Vol. 13
·期 11
·1857
·
IF 3.523
Shisong Yu,Kai Zhang,Xiangcheng Cai,Peng Tu,Yuanming Zhou,Fei Mei
Organic-inorganic perovskite materials are widely used in the preparation of light-emitting diodes due to their low raw material cost, solution preparation, high color purity, high fluorescence quantum yield, continuously tunable spectrum, and excellent charge transport properties. It has become a research hotspot in the field of optoelectronics today. At present, the nonradiative recombination and fluorescence quenching occurring at the interface between the device transport layer and the light-emitting layer are still important factors limiting the performance of perovskite light-emitting diodes (PeLEDs). In this work, based on CH3NH3PbBr3perovskite, the effects of parameters such as precursor solution, anti-solvent chlorobenzene (CB), and small amine molecule phenylmethylamine (PMA) on the performance of perovskite films and devices were investigated. The research results show that adding an appropriate amount of PMA can reduce the grain size of perovskite, improve the coverage of the film, enhance the crystallinity of the film, and increase the fluorescence intensity of the perovskite film. When the PMA content is 0.050 vol.%, the maximum luminance of PeLEDs is 2098 cd/m2and the maximum current efficiency is 1.592 cd/A, which is greatly improved by 30% and 64.8% compared with the reference device without PMA doping. These results suggest that an appropriate amount of PMA can effectively passivate the defects in perovskite films, and inhibit the non-radiative recombination caused by the traps, thereby improving the optoelectronic performance of the device.Keywords:perovskite;phenylmethylamine;chlorobenzene;light-emitting diode
研究领域:
材料科学
·
光学工程
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产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
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
·
水处理
·
化学工程
·
毒理学
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产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Kai Gao,Qing Wang,Xuexun Du,Qinglian Wei,Yongmin Huang
Dimethylamine (DMA), which is mostly generated in fine chemical industry, has enormously threatened the public health, therefore should be eliminated from water efficiently. Superior to any other methods to remove DMA, adsorbing it by sorbent could avoid the generation of secondary pollution. Among all the sorbents employed in this study, low Si/Al ratio Beta zeolite synthesized without organic template exhibits the highest performance of adsorbing DMA from water. When the transition-metal cations were introduced by ion-exchange, the adsorption of DMA was enhanced. Subsequently, the saturated adsorbent was heated in air condition, detection results of the off-gas indicated that nearly all of the DMA adsorbed was oxidized and negligible harmful by-product was produced. Beta zeolite adsorption coupled with catalytic oxidation could eliminate DMA efficiently and environmental friendly which has wide application prospects in waterworks.
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
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2018
·
IF 6.653
Ying Han,Jihe Wang,Jun Li,Zhonglin Chen,Weiwei Li,Beibei Jiang,Jie Yao
Copper corrosion products (Cu(OH)2, Cu2O, CuO and Cu2CO3(OH)2) were applied to catalyze the reduction of N-Nitrosodimethylamine (NDMA) with iron. All the copper corrosion products showed catalytic abilities. Lower pH values and DO concentrations facilitated NDMA reduction in most cases. 1,1-dimethylhydrazine (unsymmetrical dimethylhydrazine, UDMH) and dimethylamine (DMA) formed during the degradation of NDMA. There were also some undetected products. Catalytic hydrogenation was proposed as the mechanism. The catalytic systems did not promote the formation of hydrogen atoms. The dissolved copper ions in these systems were too sparse to enhance the reaction. The smooth iron surface and formation of Cu2O in each catalytic system explained the enhancement of NDMA removal. Different surface morphologies and states of Cu2O accounted for the differences in NDMA removal and kinetics between the reaction systems. This technique could be an alternative for NDMA reduction and could broaden the application of copper corrosion products.
研究领域:
环境科学
·
化学工程
·
水处理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Ying Han,Xiaoping Zheng,Beibei Jiang,Yuling Tang,Hongyuan Liu,Kemin Zhang,Yaping Guo,Jun Li
The influencing factors, products and mechanism of N -nitrosodimethylamine (NDMA) reduction by zinc (Zn) in the presence of transition-metal ions (Mn 2+ , Co 2+ and Ni 2+ ), were investigated. The NDMA removal by Zn was significantly improved by them, and the promoting effect of Co 2+ and Ni 2+ were better than Mn 2+ . With the decrease of pH values and dissolved oxygen concentrations, the removals of NDMA were enhanced in all reaction systems. NDMA was mainly reduced to unsymmetrical dimethylhydrazine (UDMH) in Zn and Zn/Mn 2+ systems. It was mainly reduced to dimethylamine (DMA) and ammonium (NH 4 + ) in Zn/Co 2+ and Zn/Ni 2+ systems. There were undetected products in all reaction systems. Catalytic hydrogenation was the main mechanism, and active hydrogen atom was the main active species. The presence of Mn 2+ , Co 2+ and Ni 2+ promoted the corrosion of Zn and changed the surface morphology of Zn. The formation of type I film on Zn surface was promoted in the presence of Co 2+ and Ni 2+ , which was conducive to the continuous corrosion of Zn and hydrogen generation. While type II film which would inhibit the corrosion of Zn formed on Zn surface in the presence of Mn 2+ . MnO 2 , Co 3 O 4 and Ni(OH) 2 were formed in Zn/Mn 2+ , Zn/Co 2+ and Zn/Ni 2+ systems, respectively. They would facilitate more generation of active hydrogen atoms.
研究领域:
环境化学
·
水处理
·
催化
·
材料科学
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产品关联
DOI
高影响因子
CHEMOSPHERE
·
2016
·
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
危险品化学品经营许可证（带存储）