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Elucidation of the last steps of photo-ammonification:analytical method development and mechanism elucidation

Frontiers of Environmental Science & Engineering 2024年第8期18卷 101-106页

作者： Yingjing Miao Hui Wang Chunpeng Yang Ruochun Zhang Hao Zhang Peizhe Sun School of Environmental Science and Engineering Tianjin UniversityTianjin 300072China SINOPEC Research Institute of Petroleum Processing Co. Ltd.Beijing 100083China School of Earth System Science Tianjin UniversityTianjin 300072China

The mechanisms underlying the photo-ammonification of nitrogenous organic compounds(NOCs)remain unclear,partly due to the analytical challenges of small NOC *** study introduced a simple methodology for accurately and simultaneously quantifying multiple small NOCs during ammonification *** developed method employed phenyl isothiocyanate as derivatization reagents,followed by high-performance liquid chromatography analysis to measure primary and secondary amines,amides,as well as NH4+over variable photo-ammonification *** our experimental setup,vacuum ultraviolet(VUV)irradiation serves as the controlled reaction environment to simulate harsh photo-ammonification *** NOCs,including pyridine,N,N-dimethylformamide,and acrylonitrile,were chosen due to their structural diversity and environmental relevance as model *** method was able to achieve excellent nitrogen mass balance,and revealed that the last steps of photo-ammonification involved oxidation of nitrogen-adjacent carbon to amide followed by the cleavage of N-C *** novel method may also help quantitative investigation of nitrogen transformations in different environmental contexts.

关键词： ammonification NOCs Amines Nitrogen mass balance

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Effects of Heavy Metals on ammonification, Nitrification and Denitrification in Maize Rhizosphere

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Pedosphere 2001年第2期11卷 115-122页

作者： CHENYINGXU YANGYE 等 DpartmentofEnivronmentalEngineering ZhejiangUniversityHangzhou310029（China） DpartmentofEnivronmentalEngineering ZhejiangUniversityofTechnologyHangzhou310032（China）

The ammonification, nitrification and denitrification in maize rhizosphere of alluvial soils were compared with those in the bulk soil after exposure to different kinds of heavy metals. The addition of cadmium at low levels (2 mg kg-1 and 5 mg kg-1) could stimulate the ammonification and nitrification in the soils, while inhibition influences were found at high levels of Cd addition (10 mg kg-1 and 20 mg kg-1). The relationship between microbial activity and cadmium concentration varied with the kind of microorganisms. The nitrifying bacteria were more sensitive to cadmium pollution than the ammonifying bacteria. When Cd(II), Cu(II) and Cr(VI) were compared at the same addition concentration of 20 mg kg-1 soil, Cd(II) was the most effective inhibitor of ammonification and denitrification among the three investigated heavy metals, and Cr(VI) had the most strong inhibitory influence on the nitrifying bacteria. The microbial activities in rhizosphere were higher than those in the bulk soil for most of the treatments. Cr(VI) proved to be the most effective in enhancing the microbial activities in rhizosphere, and this could be caused by the positive reduction of Cr(VI) to Cr(III) in rhizosphere, and the relatively sufficient existence of organic matter which intensified the adsorption of the metal. It seemed that the rhizosphere had some mitigation effect on heavy metal toxicity.

关键词： ammonification denitrification heavy metal pollution nitrification rhizosphere

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Enhancement of Alkene Epoxidation Activity of Titanosilicates by Gas-Phase Ammonia Modification

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Chinese Journal of Chemistry 2012年第9期30卷 2205-2211页

作者：张里艳徐乐孙晶晶蒋金刚刘月明吴海虹吴鹏 Shanghai Key Laboratory of Green Chemistry and Chemical Processes Department of ChemistryEast China Normal UniversityShanghai 200062China

Novel ammonia-treated titanosilicates have been prepared by heating the samples of Ti-MWW, TS-l and Ti-Beta under pure ammonia gas flow at 673 K for a period of time. The ammonia modification improved their catalytic performance in liquid-phase oxidations. Especially, the catalytic activities of ammonified Ti-MWW, N-Ti-MWW, were enhanced greatly in the epoxidation of 1-hexene with H2O2. The reason that the ammonia treat- ment played such an important role in post-modification of titanosilicate was investigated in details. In comparison to the parent Ti-MWW catalyst, N-Ti-MMW was more robust and produced less coke in oxidation reactions.

关键词： titanosilicates Ti-MWW epoxidation ammonification ammonia

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Ecotoxicological effect of zinc oxide nanoparticles on soil microorganisms

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Frontiers of Environmental Science & Engineering 2015年第5期9卷 912-918页

作者： Zhaoyi SHEN Zhuo CHEN Zhen HOU Tingting LI Xiaoxia LU Laboratory for Earth Surface Processes (Ministry of Education) College of Urban and Environmental Sciences Peking University Beijing 100871 China

The widespread production and use of zinc oxide nanoparticles （ZnO-NPs） in recent years have posed potential threat to the ecosystem. This study aimed to investigate the ecotoxicological effect of ZnO-NPs on soil microorganisms using laboratory microcosm test. Respira- tion, ammonification, dehydrogenase （DH） activity, and fluorescent diacetate hydrolase （FDAH） activity were used as ecotoxicological parameters. The results showed that in the neutral soil treated with 1 mg ZnO-NPs per g soil （fresh, neutral）, ammonification was significantly inhibited during the study period of three months, but the inhibition rate decreased over increasing time. Inhibition in respira- tion was observed in the first month of the test. In various ZnO-NPs treatments （1 rag, 5 rag, and 10 mg ZnO-NPs per g soil）, DH activity and FDAH activity were inhibited during the study period of one month. For both enzyme activities, there were positive dose-response relationships between the concentration of ZnO-NPs and the inhibition rates, but the curves changed over time due to changes of ZnO-NPs toxicity. Soil type affected the toxicity of ZnO- NPs in soil. The toxicity was highest in the acid soil, followed by the neutral soil. The toxicity was relatively low in the alkaline soil. The toxicity was not accounted for by the Zn2＋ released from the ZnO-NPs. Direct interaction of ZnO-NPs with biologic targets might be one of the reasons. The adverse effect of ZnO-NPs on soil micro- organisms in neutral and acid soils is worthy of attention.

关键词： zinc oxide nanoparticles (ZnO-NPs) soilmicroorganisms respiration ammonification dehydrogen-ase (DH) activity fluorescent diacetate hydrolase (FDAH)activity

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Reaction of Ferralsol to Acidifying Effect of Nitrogen Fertilisation

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Journal of Agricultural Chemistry and Environment 2021年第1期10卷 69-79页

作者： John Stephen Tenywa Jean Bosco Ngarukiyimana Alice Amoding Katushabe College of Agricultural and Environmental Sciences Makerere University Kampala Uganda

Background: The objective of this study was to determine the short-term effect of urea fertiliser application on soil reactions in a Ferralsol, with particular thrust on P sorption. Methods: Two experiments were conducted for this purpose: 1) a screenhouse pot experiment; and 2) a laboratory P sorption component. The pot (10 litre capacity plastic pots) experiment was conducted at the Makerere University Agricultural Research, Kabanyolo in Uganda, using a Ferralsol. The study comprised of four urea N (46% N) fertiliser treatments, namely, 0, 40, 80 and 120 kg N·ha-1, equivalent to 0, 200, 400 and 600 mg N per pot. A completely randomised design was adopted with three replicates. Urea rates were applied in 50% split doses, one at planting and the other at 19 days after seedling emergence (to simulate farmer practice). This was followed by watering to field capacity using distilled water. Soil samples were taken at three daily intervals until day fourteen;thereafter, soil sampling was at an interval of seven days. The second urea split dose was applied at 21 days followed by soil sampling at an interval of three days till day fourteen. Thereafter, soil was sampled at seven day intervals until the end of experiment. Soil samples were analysed for exchangeable H+, Al3+, NH4+and NO3- ions. The reaction trends of the concentrations of these ions and Bray 1 P were used to structure different response curves repres

关键词： Urea Hydrolysis ammonification Phosphorus Sorption

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