Coordinative interaction between nitrogen oxides and iron–molybdenum POM Mo72Fe30

2019 ◽  
Vol 48 (20) ◽  
pp. 6984-6996 ◽  
Author(s):  
Kirill V. Grzhegorzhevskii ◽  
Margarita O. Tonkushina ◽  
Andrei V. Fokin ◽  
Ksenia G. Belova ◽  
Alexander A. Ostroushko
Keyword(s):  
Nitrogen Oxides ◽  
Nitrogen Monoxide ◽  
Argon Atmosphere ◽  
Ambient Conditions ◽  
Adsorption Of Nitrogen

The process of adsorption of nitrogen monoxide and dioxide by the giant Keplerate nanocluster Mo72Fe30 was studied in detail under ambient conditions and air/argon atmosphere.

scholarly journals Air pollution by nitrogen oxides in Sarajevo from 2005 to 2010

2013 ◽  
Vol 3 (3) ◽  
pp. 250-254
Author(s):  
Suad Habeš ◽  
Zarema Obradović ◽  
Aida Ridžal ◽  
Asmir Aldžić
Keyword(s):  
Air Pollution ◽  
Nitrogen Oxides ◽  
Positive Result ◽  
Nitrogen Dioxide ◽  
Total Concentration ◽  
Nitrogen Monoxide ◽  
Atmospheric Conditions ◽  
Measuring Point ◽  
Limit Values ◽  
Research Show

Introduction: Air pollution occurs when the concentration of certain substances (pollutants) reaches a size which causes its toxicity, or in other words, begins to cause harm to human health, fl ora and wildlife.Methods: Measurements were performed in the period from 2005 to 2010, at the measuring point Bjelave-Sarajevo by the method of Griess-Saltzmann. It encompasses the following parameters: NO, NO2, NOx, measured concentrations of pollutants in the atmosphere reduced to normal atmospheric conditions of 293 K (Kelvin) and pressure of 101.3 kPa (kilopascal).Results: NO concentration in the period from 2005 to 2008 was above the permitted value, but the results of research in the period between 2009 and 2010, have shown that there was a decrease in NO concentration in the atmosphere. Measurements show that the concentration of this pollutant is currently declining, which is a positive result compared to the pollution of the atmosphere by nitrogen monoxide. Furthermore, the results of the research showed that the concentration of NO2 for the period of 2005 to 2010, is in the limited values, and that has a decreasing trend, which is also a positive result compared to the pollution of the atmosphere by nitrogen dioxide. Related to the total concentration of NOx in the atmosphere, the results of the research show that their representation corresponds to the limit values existing in the Rulebook on limit values for air quality.Conclusion: The results of the research for the pollution of the atmosphere by nitrogen oxides in the investigated area show that the amount of nitrogen oxides in the atmosphere is in constant decline.

scholarly journals STUDY OF THE OXIDATION PROCESS OF NITROGEN OXIDES BY OZONE

2021 ◽  
pp. 62-70
Author(s):  
I.A. Volchyn ◽  
O.M. Kolomiets ◽  
S.V. Mezin ◽  
A.O. Yasynetskyi
Keyword(s):  
Nitrogen Oxides ◽  
Conversion Efficiency ◽  
Power Plants ◽  
Oxidation Process ◽  
Thermal Power ◽  
Nitrogen Monoxide ◽  
Molar Ratio ◽  
Gas Temperature ◽  
Gas Treatment ◽  
Industrial Enterprises

The need to reduce emissions of pollutants, in particular nitrogen oxides, as required by regulations in Ukraine, requires the use of modern technologies and methods for waste gas treatment at industrial enterprises. This is especially true of thermal power plants, which are powerful sources of nitrogen oxide emissions. The technological part of the wet or semi-dry method of purification is the area for the oxidation of nitrogen oxides to obtain easily soluble compounds. The paper presents the results of a study of the process of ozone oxidation of nitrogen oxides in a chemical reactor. Data for the analysis of the process were obtained by performing physical experiments on a laboratory installation and related calculations on a mathematical model. Studies of the oxidation process have shown that the required amount of ozone depends not only on the content of nitrogen monoxide, but also on the content of nitrogen dioxide. The process of conversion of nitrogen monoxide to a satisfactory level occurs at the initial value of the molar ratio of ozone to nitrogen monoxide in the range of 1.5…2. The conversion efficiency of nitrogen monoxide reaches 90% at a gas temperature less than 100 °C. To achieve high conversion efficiency at gas temperatures above 100 °C, it is necessary to increase the initial ozone content when the molar ratio exceeds 2. The analysis shows that the conversion efficiency of nitric oxide largely depends on the residence time of the gas mixture in the reaction zone. Due to lack of time under certain conditions, the efficiency decreases by approximately 46%. To increase it, it is necessary to accelerate the rate of oxidation reactions due to better mixing of gases by turbulence of the flow in the oxidizing reactor. Bibl. 6, Fig. 6, Tab. 3.

THEORETICAL STUDY OF NITROGEN MONOXIDE ADSORPTION ON RHODIUM CLUSTERS AT DIFFERENT SITES

2008 ◽  
Vol 07 (04) ◽  
pp. 669-679 ◽  
Author(s):  
JIAN CHEN ◽  
KAI TAN ◽  
MENG-HAI LIN
Keyword(s):  
Density Functional ◽  
Nitrogen Monoxide ◽  
Density Functional Theory Calculations ◽  
Frontier Orbitals ◽  
Functional Theory ◽  
Orbital Interactions ◽  
Adsorption Sites ◽  
Rhodium Clusters ◽  
Adsorption Of Nitrogen ◽  
Back Donation

The adsorption of nitrogen monoxide NO with charged and neutral [Formula: see text] clusters at atop, bridge, and threefold hollow sites had been investigated by density functional theory calculations. The results showed that rhodium clusters had strong orbital interactions with NO and formed the complex [ Rh n NO ]-/0/+. The stretching vibrational frequencies of the N–O bonds changed with the different adsorption sites and clusters sizes. The interactions between rhodium clusters and NO molecular could be described through the donation and back-donation of their frontier orbitals. The more back donation from Rh to NO , the weaker the N–O bonds, exhibiting that the lengthening of the N–O bond length and the lowering of its vibrational frequency. In general, the donation and back-donation interactions followed the tendencies: anionic > neutral > cationic, big size > small size, threefold hollow site > bridge site > atop site.

Removal efficiency of an integrated adsorption/photocatalysis system for reducing low concentrations of nitrogen oxides in microenvironments of museums for cultural relics conservation

2016 ◽  
Vol 25 (8) ◽  
pp. 1185-1196 ◽  
Author(s):  
Dawei Wang ◽  
Danian Zhang ◽  
Yan Wu ◽  
Hua Wei ◽  
Jing Luo ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Removal Efficiency ◽  
Photocatalytic Oxidation ◽  
Removal Rate ◽  
Nitrogen Monoxide ◽  
Bamboo Charcoal ◽  
Low Concentrations ◽  
Integrated Device ◽  
Direct Use ◽  
Cultural Relics

Nitrogen oxides (NOx) could pose a threat to the conservation of cultural relics and could also enhance the corrosion induced by other pollutants such as sulphur dioxides and organic acids. The NOx removal rate was studied through a combination of adsorption onto bamboo charcoal and photocatalysis. The integrated NOx removal efficiency by both methods was evaluated in both lab and pilot scales. The studies have shown that the direct use of biomass can remove moderate level of NOx; while higher level of NOx removal was achieved by using bamboo charcoal carbonized at 520℃. The photocatalytic oxidation of NOx was found to be well fit with Langmuir–Hinshelwood model. The different carriers of photocatalysis combined with adsorbents were compared, and the optimised process was shown to reduce the nitrogen monoxide and nitrogen dioxide level to 2.76 and 0.68 µg/m3, respectively, in 20% relative humidity (RH). An integrated device was developed, and the results have demonstrated that the combined technologies of photocatalysis and adsorption can have great removal potential for reducing NOx and therefore in improving the air quality under different RH conditions.

The adsorption of nitrogen oxides and water on rare-earth ion-exchanged ZSM-5: a density functional study

2002 ◽  
Vol 202 (3-4) ◽  
pp. 283-288 ◽  
Author(s):  
Yi Luo ◽  
Xiaohong Wan ◽  
Yuki Ito ◽  
Seiichi Takami ◽  
Momoji Kubo ◽  
...  
Keyword(s):  
Rare Earth ◽  
Nitrogen Oxides ◽  
Density Functional ◽  
Functional Study ◽  
Rare Earth Ion ◽  
Density Functional Study ◽  
Adsorption Of Nitrogen

scholarly journals The IAGOS NO<sub>x</sub> Instrument – Design, Operation and First Results from Deployment aboard Passenger Aircraft

2017 ◽  
Author(s):  
Florian Berkes ◽  
Norbert Houben ◽  
Ulrich Bundke ◽  
Harald Franke ◽  
Hans-Werner Pätz ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Ambient Pressure ◽  
Nitrogen Monoxide ◽  
High Time Resolution ◽  
Total Uncertainty ◽  
Autonomous Operation ◽  
First Results ◽  
The Difference ◽  
Using Data ◽  
Passenger Aircraft

Abstract. We describe the nitrogen oxides instrument designed for the autonomous operation on board of passenger aircraft in the framework of the European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System, http://www.iagos.org). We demonstrate the performance of the instrument using data from two deployment periods aboard an A340-300 aircraft of Deutsche Lufthansa. The well-established hemiluminescence detection method is used to measure nitrogen monoxide (NO) and nitrogen oxides (NOx). NOx is measured using a photolytic converter, and nitrogen dioxide (NO2) is determined from the difference between NOx and NO. This technique allows to measure at high time resolution (4 s) and high precision (2σ) in the low ppt range (NO of 24 ppt and NOx of 35 ppt) over different ambient temperature and ambient pressure altitude ranges (from surface pressure down to 190 hPa). The IAGOS NOx instrument is characterized for (1) calibration stability and total uncertainty (2) humidity and chemical interferences (e.g. ozone, HONO, PAN) and (3) inter-instrumental precision. We demonstrate that the IAGOS NOx instrument is a robust, fully automated, and long-term stable instrument suitable for unattended operation on airborne platforms, which provides useful measurements for future air quality studies and emission estimates.

scholarly journals A research on fuelling a truck diesel engine with hydrogen

2019 ◽  
Vol 112 ◽  
pp. 01011
Author(s):  
Nikolaos Cristian Nutu ◽  
Constantin Pana ◽  
Niculae Negurescu ◽  
Alexandru Cernat ◽  
Dinu Fuiorescu ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Diesel Fuel ◽  
Nitrogen Monoxide ◽  
Experimental Investigations ◽  
Test Bed ◽  
Smoke Emission ◽  
Emission Level ◽  
Theoretical Investigations ◽  
Semi Empirical

The paper presents experimental and theoretical investigations results of a truck diesel engine fuelled with diesel fuel and hydrogen by diesel-gas method. The purpose of the paper is to reduce the level of the nitrogen oxides emission level and to improve the overall performances of the engine. The use of hydrogen represents a suitable method to reduce the classic fuels consumption, maintaining the energetic performances of the engine. The test bed situated in the Thermotechnics, Engines, Thermal Equipments and Refrigeration Instalations Department of University Politechnica of Bucharest was adapted for hydrogen fuelling of the truck diesel engine. The engine used for investigations is a turbocharged 10.2 l truck diesel engine which run at 1450 rpm and 40% engine load. By hydrogen fuelling if the investigated diesel engine a decrease has been achieved in the nitrogen oxides emission level and in the smoke emission level. Also the break energetic specific consumption decreased compared to the standard diesel engine. The theoretical investigations presented in tha paper are based on a semi-empirical corellation, used to simulate the nitrogen monoxide emission formation. The results of the experimental investigations confirm de viability of hydrogen as an alternative fuel for the diesel engine.

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