Topic
Ammonia
About: Ammonia is a research topic. Over the lifetime, 16217 publications have been published within this topic receiving 271940 citations. The topic is also known as: NH3 & azane.
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TL;DR: In this paper, the rate of CO 2 absorption into a falling thin film has been measured using a wetted-wall column for aqueous ammonia between 0.6 and 6.5 times smaller than MEA at the measured temperatures, and it was shown that the difference in mass transfer rate is likely due to both the reduced temperature and differences in reactivity between ammonia and MEA with CO 2.
215 citations
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TL;DR: Nitrosomonas eutropha, an obligately lithoautotrophic bacterium, was able to nitrify and denitrify simultaneously under anoxic conditions when gaseous nitrogen dioxide (NO2) was supplemented to the atmosphere.
Abstract: Nitrosomonas eutropha, an obligately lithoautotrophic bacterium, was able to nitrify and denitrify simultaneously under anoxic conditions when gaseous nitrogen dioxide (NO2) was supplemented to the atmosphere. In the presence of gaseous NO2, ammonia was oxidized, nitrite and nitric oxide (NO) were formed, and hydroxylamine occurred as an intermediate. Between 40 and 60% of the produced nitrite was denitrified to dinitrogen (N2). Nitrous oxide (N2O) was shown to be an intermediate of denitrification. Under an N2 atmosphere supplemented with 25 ppm NO2 and 300 ppm CO2, the amount of cell protein increased by 0.87 mg protein per mmol ammonia oxidized, and the cell number of N. eutropha increased by 5.8 × 109 cells per mmol ammonia oxidized. In addition, the ATP and NADH content increased by 4.3 μmol ATP (g protein)–1 and 6.3 μmol NADH (g protein)–1 and was about the same in both anaerobically and aerobically grown cells. Without NO2, the ATP content decreased by 0.7 μmol (g protein)–1, and the NADH content decreased by 1.2 μmol (g protein)–1. NO was shown to inhibit anaerobic ammonia oxidation.
214 citations
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TL;DR: In this article, a model of a V2O5-MoO3-TiO2 DeNOx catalyst has been presented and briefly characterized, and the adsorption of urea on it has also been investigated.
Abstract: A model V2O5–MoO3–TiO2 DeNOx catalyst has been prepared and briefly characterized. The adsorption of urea on it (and of ammonia for comparison) has also been investigated. It has been observed that urea can adsorb over the catalyst in an anionic form that can later decompose to isocyanate anions and ammonia and ammonium ion species. This mechanism suggests that the potential reactivity of the anionic form of urea and of isocyanate anions with VOCs, if they are present in the waste gas, possibly rise to polluting compounds must be taken into account for applications of the urea/DeNOx process.
213 citations
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TL;DR: Besides the relatively small contribution from commercial ammonical fertilizer production, replenishing of the nitrogen pool falls mainly to a limited number of physiologically diverse microbes that contain the nitrogenase enzyme system.
Abstract: In the simplest terms, the biological nitrogen cycle is the reduction of atmospheric dinitrogen (N2) to ammonia with the subsequent reoxidation ammonia to dinitrogen (1). At the reduction level of ammonia, nitrogen incorporated into precursors for biological macromolecules such as proteins and nucleic acids. Reoxidation of ammonia to dinitrogen ("denitrification") by a variety of microbes (by way of nitrite and other oxidation levels of nitrogen) leads to the depletion of the "fixed," biologically usable, nitrogen pool. Besides the relatively small contribution from commercial ammonical fertilizer production, replenishing of the nitrogen pool falls mainly to a limited number of physiologically diverse microbes (e.g. eubacteria and archaebacteria; free-living and symbiotic; aerobic and anaerobic) that contain the nitrogenase enzyme system.
213 citations
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TL;DR: In this paper, the selective catalytic reduction of nitric oxide with ammonia in the presence of oxygen has been studied on Cu2+ ion-exchanged zeolite catalysts.
212 citations