Dinitrogen Monoxide Research Articles

Gas-Phase Preparation of Subvalent Germanium Monoxide (GeO, X1Σ+) via Non-Adiabatic Reaction Dynamics in the Exit Channel.

The subvalent germanium monoxide (GeO, X1Σ+) molecule has been prepared via the elementary reaction of atomic germanium (Ge, 3Pj) and molecular oxygen (O2, X3Σg-) with each reactant in its electronic ground state by means of single-collision conditions. The merging of electronic structure calculations with crossed beam experiments suggests that the formation of germanium monoxide (GeO, X1Σ+) commences on the singlet surface through unimolecular decomposition of a linear singlet collision complex (GeOO, i1, C∞v, 1Σ+) via intersystem crossing (ISC) yielding nearly exclusively germanium monoxide (GeO, X1Σ+) along with atomic oxygen in its electronic ground state [p1, O(3P)]. These results provide a sophisticated reaction mechanism of the germanium-oxygen system and demonstrate the efficient "heavy atom effect" of germanium in ISC yielding (nearly) exclusive singlet germanium monoxide and triplet atomic oxygen compared to similar systems (carbon dioxide and dinitrogen monoxide), in which non-adiabatic reaction dynamics represent only minor channels.

Economic and Environmental Assessment Using Two Renewable Sources of Energy to Produce Heat and Power for Industrial Applications

Economic criteria have prevailed in studies on integration of renewable energies. Tons of dangerous emissions are emitted by a biomass fuel, causing negative impacts over atmosphere and health. Current research proposes Pinch Analysis of solar thermal energy and the joint use of biomass (sugarcane bagasse) to produce heat and power in a Caribbean sugar mill; measuring emissions like: carbon oxide CO, carbon dioxide CO2, dinitrogen monoxide N2O, nitrogen oxides NOx, sulfur oxides SOx, non-methane volatile organic compounds NMVOC, methane CH4, and particulate matters, to have a global and clear view of the impacts of biomass as a renewable fuel. Variables like kWh cost, the installation and device area of renewable energy, and greenhouse gas emissions, are analysed to assess the effect on the integration final design, the target of which is to control the use of biomass. It is possible to produce an economically competitive integration design of solar system LCOEth solar = 0.0636 USD/kWh, LCOEele = 0.1392 USD/kWh), zero greenhouse gases emissions (ΔTminrew=7 °C), and deletion of 378,711.53 t/year of CO2 and 9567.56 t/year of solid particles. There are many possibilities that can implemented; in one of them, bagasse burning is reduced by 30% and the solar collector network for required power production is reduced by 68%.

Recirculating treated sewage sludge for agricultural use: Life cycle assessment for a circular economy

The objective of this study is to assess the environmental value of recirculating nutrients from treated sewage sludge by application to agricultural soils to grow forage as opposed to landfilling and incineration. The methodological choices are aligned to the circular economy framework using life cycle assessment. Consequential modeling and open loop modeling were adopted and adhere to ISO 14044 and International Reference Life Cycle Data System (ILCD) standards. The functional unit is defined in terms of the amounts of nitrogen (N), phosphorus (P) and potassium (K) recirculated from the treated sewage sludge produced annually in Kuwait. The results indicate a reduction in environmental burden with respect to fossil fuel depletion, metal depletion and climate change. A total of 95% of the reduction is realized by avoiding virgin nitrogen production and instead using its recirculated counterpart. Considerable amounts of natural gas, coal, dinitrogen monoxide (nitrous oxide, N2O) and copper are consumed during virgin N fertilizer production.

Investigating the Photochemical Decomposition of Solid 1,3,5-Trinitro-1,3,5-triazinane (RDX).

Energetic materials such as 1,3,5-trinitro-1,3,5-triazinane (RDX) are known to photodissociate when exposed to UV light. However, the fundamental photochemical process(es) that initiate the decomposition of RDX is (are) still debatable. In this study we investigate the photodissociation of solid-phase RDX at four distinct UV wavelengths (254 nm (4.88 eV), 236 nm (5.25 eV), 222 nm (5.58 eV), 206 nm (6.02 eV)) exploiting a surface science machine at 5 K. We also conducted dose-dependent studies at the highest and lowest photon energy of 206 nm (6.02 eV) and 254 nm (4.88 eV). The products were monitored online and in situ via infrared spectroscopy. During the temperature-programmed desorption phase, the subliming products were detected with a reflectron time-of-flight mass spectrometer coupled with soft-photoionization at 10.49 eV (PI-ReTOF-MS). Infrared spectroscopy revealed the formation of small molecules including nitrogen monoxide (NO), nitrogen monoxide dimer ([NO]2), dinitrogen trioxide (N2O3), carbon dioxide (CO2), carbon monoxide (CO), dinitrogen monoxide (N2O), water (H2O), and nitrite group (-ONO) while ReTOF-MS identified 32 cyclic and acyclic products. Among these, 11 products such as nitryl isocyanate (CN2O3), 5-nitro-1,3,5-triazinan-2-one (C3H6N4O3) and 1,5-dinitro-1,3,5-triazinan-2-one (C3H5N5O5) were detected for the first time in photodecomposition of RDX. Dose-dependent in combination with wavelength-dependent photolysis experiments aid to identify key primary and secondary products as well as distinguished pathways that are more preferred at lower and higher photon energies. Our experiments reveled that N-NO2 bond fission and nitro-nitrite isomerization are the initial steps in the UV photolysis of RDX. Reaction mechanisms are derived by comparing the experimental findings with previous electronic structure calculations to rationalize the origin of the observed products. The present study can assist in understanding the complex chemistry behind the photodissociation of electronically excited RDX molecule, thus bringing us closer to unraveling the decomposition mechanisms of nitramine-based explosives.

Bioconversion of fruit and vegetable waste into earthworms as a new protein source: The environmental impact of earthworm meal production

Food waste is recognized as a global issue affecting the sustainability of the food supply chain. The unnecessary exploitation of natural resources (land, water and fossil energy) and production of greenhouse gas emissions (GHG) make the reduction of food waste a key point. In this context, the use of fruit and vegetable waste (FVW) as growth substrate for fresh earthworms to produce dried meal for feed and food purpose can be recognized as a viable solution.Therefore, the aim of this study is to evaluate the environmental impact of the bioconversion of FVW into earthworm meal to be used as new food/feed source. This is carried out by adopting the Life Cycle Assessment (LCA) method with an attributional approach and solving the multifunctionality of the system with an economic allocation between earthworms and vermicompost.The results show that the main process hotspots are the emissions of methane, dinitrogen monoxide and ammonia taking place during vermicomposting, as well as FVW transport and electricity consumed during fresh earthworm processing. Respect to the one used as feed, the dried meal with food purpose shows a higher impact due to the higher economic value and to the higher electricity consumed during freeze drying compared to the oven-drying process for feed meal production. Enhancing productivity and reducing energy consumption are necessary to improve the sustainability of earthworm meal as food/feed source.

Estimation of emissions of air pollutants in the Krapina-Zagorje county

The Program for the protection of air quality, ozone layer, climate change mitigation and adaptation of the Krapina-Zagorje County is prepared in accordance with the Article 12 of the Air Protection Act (OG 130/11, 47/14, 61/17, 118/18). The Program sets targets and measures by priority sectors, deadlines and responsible authorities for measures implementation over a five-year period in the County. For the purpose of defining protection measures, based on available data, estimation of annual emissions of pollutants into air was performed: nitrogen oxides, carbon monoxide, sulphur oxides, particles, volatile organic compounds, ammonia, carbon dioxide, methane and dinitrogen monoxide from the main sectors. Emissions were estimated using the EMEP/EEA methodology and 2006 IPCC Guidelines for National Greenhouse Gas Inventories methodology. Road traffic emissions were estimated using DEFRA/DECC methodology. Based on the results on estimated pollutant emissions in the County, appropriate measures have been defined for the protection and improvement of air quality.

First vibrational investigations of N2O–H2O, N2O–(H2O)2, and (N2O)2–H2O complexes from the far to the near-infrared spectral region by neon matrix isolation and ab initio calculations

We present for the first time the investigation of water molecules complexed with dinitrogen monoxide, two abundant molecules in atmosphere, in solid neon using Fourier transform infrared (IR) spectroscopy. We identify at least three complexes from concentration effects, N2O-H2O, N2O-(H2O)2, and (N2O)2-H2O, by observation of new absorption bands close to the monomer fundamental modes from the far to the near IR region. We highlight the presence of isomers for the N2O-H2O complex with the help of theoretical calculations at second order Møller-Plesset (MP2) and coupled-cluster single double triple-F12a/aug-cc-pVTZ levels. The observed frequencies for the N2O-(H2O)2 and (N2O)2-H2O complexes are compared with MP2/aug-cc-pVTZ harmonic data. Anharmonic coupling constants have been derived from the observations of overtones and combination bands.

N2O absorption through super hydrophobic hollow fiber membrane contactor

Dinitrogen monoxide (N2O) is mainly produced in Horticulture and farming activities, industrial processes and combustion of fossil fuels. N2O is one of the harmful emissions and its global warming potential is 310 times greater than CO2 on a molecular basis. This research aims to absorb N2O from its mixture with air through super hydrophobic hollow membrane contactor using a mixture of 0.5M HNO3 and 0.5 wt % H2O2 solutions as absorbent. In the experiment, the feed gas flowed through the shell side of the contactor, while absorbent solution flowed through the lumen fibers. Experimental results show that the amount of N2O absorbed and N2O absorption efficiency increased with the absorbent flow rate and the number of fibers in the contactor resulting from the increase in the turbulence and surface area for gas–liquid contact, respectively. The overall mass transfer coefficient and the flux increased with the absorbent flow rate due to the decrease of the mass transfer resistance in the liquid phase. However, the overall mass transfer coefficient and the flux decreased with the number of fibers in the contactor due to the decrease of the absorbent flow rate in a single fiber. The amount of N2O absorbed and the flux increased but the N2O absorption efficiency decreased with increasing the feed gas cross flow rate. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 362–366, 2019

Measurement uncertainty of coulometric trace humidity sensors

Abstract Especially trace amounts of water vapour in gases can be reliably determined by coulometric trace humidity sensors. The principle of these sensors is based on water vapour absorption in a hygroscopic layer and its subsequent electrolytic decomposition. The calibration of sensors was performed in the humidity range, expressed as frost point temperature, from − 30 ° C -30\hspace{0.1667em}^\circ \mathrm{C} to − 80 ° C -80\hspace{0.1667em}^\circ \mathrm{C} . This range is equivalent to volume fractions smaller than 376 µL·L−1. Generated humidity was measured with coulometric sensors and a chilled dew point hygrometer that was used as reference. An empirical non-linear function was found between sensor signal and measured reference humidity. This function consists of two parameters with a measurement uncertainty. Both calibration parameters were checked by means of one-way analysis of variance. It showed that gas specific function can be used for humidity measurement in nitrogen, hydrogen, dinitrogen monoxide, compressed and synthetic air. It is possible to determine trace humidity in all tested gases with an expanded uncertainty less than 2.1 K (coverage factor k = 2 k=2 ) regarding frost point temperature.

Surface Modification of Recycled Carbon Fibers by Use of Plasma Treatment

In this study, sized and thermally desized virgin carbon fibers (vCF) as well as recycled carbon fibers (rCF) from a thermal recycling process are plasma treated by a plasma-jet. The effect of two different process gases (nitrogen and dinitrogen monoxide) and the influence of the distance between the plasma source and the fiber surface are studied with the aim of increasing the oxygen and nitrogen concentration on the rCF surfaces. Higher surface coverage of oxygen-and nitrogen-containing functional groups is supposed to lead to a better adhesion between the carbon fiber and the epoxy resin matrix. The elemental compositions and functional groups of the treated carbon fiber surfaces are studied by x-ray photoelectron spectroscopy. The effect of plasma treatment on the fiber properties like tensile strength, tensile modulus and surface roughness is investigated.

Synthesis and properties of Pr3+-doped ZnO nanowires

Well-aligned Pr3+-doped ZnO nanowires (NWs) were obtained by chemical vapor deposition (CVD) method without catalysts on silicon substrates by vapor-solid process. The length and diameter of ZnO NWs were 1–2 μm and 50–100 nm, respectively. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) have been used to characterize the obtained Pr3+-doped ZnO nanowires. The concentration of dopant in the synthesized nanowires was 0.7 at %, according to EDX measurements. XPS was also used to characterize the samples and to confirm their composition. Pr3+-doped ZnO sensors were fabricated using a focused ion beam (FIB) with Au/Ti electrodes. A nanosensor is invented from an individual zinc oxide nanowire (80 nm in diameter). Response characteristics of the single nanowire towards dinitrogen monoxide (N2O), hydrogen (H2), ammonia (NH3) were examined at room temperature at different concentrations of gases.

Ozone and dinitrogen monoxide production in atmospheric pressure air dielectric barrier discharge plasma effluent generated by nanosecond pulse superimposed alternating current voltage

The effects of nanosecond pulse superposition to alternating current voltage (NS + AC) on the generation of an air dielectric barrier discharge (DBD) plasma and reactive species are experimentally studied, along with measurements of ozone (O3) and dinitrogen monoxide (N2O) in the exhausted gas through the air DBD plasma (air plasma effluent). The charge-voltage cycle measurement indicates that the role of nanosecond pulse superposition is to induce electrical charge transport and excess charge accumulation on the dielectric surface following the nanosecond pulses. The densities of O3 and N2O in NS + AC DBD are found to be significantly increased in the plasma effluent, compared to the sum of those densities generated in NS DBD and AC DBD operated individually. The production of O3 and N2O is modulated significantly by the phase in which the nanosecond pulse is superimposed. The density increase and modulation effects by the nanosecond pulse are found to correspond with the electrical charge transport and the excess electrical charge accumulation induced by the nanosecond pulse. It is suggested that the electrical charge transport by the nanosecond pulse might result in the enhancement of the nanosecond pulse current, which may lead to more efficient molecular dissociation, and the excess electrical charge accumulation induced by the nanosecond pulse increases the discharge coupling power which would enhance molecular dissociation.

Including GHG emissions from mangrove forests LULUC in LCA: a case study on shrimp farming in the Mekong Delta, Vietnam

PurposeMangrove forests have been recognized as important regulators of greenhouse gases (GHGs), yet the resulting land use and land-use change (LULUC) emissions have rarely been accounted for in life cycle assessment (LCA) studies. The present study therefore presents up-to-date estimates for GHG emissions from mangrove LULUC and applies them to a case study of shrimp farming in Vietnam.MethodsTo estimate the global warming impacts of mangrove LULUC, a combination of the International Panel for Climate Change (IPCC) guidelines, the Net Committed Emissions, and the Missed Potential Carbon Sink method were used. A literature review was then conducted to characterize the most critical parameters for calculating carbon losses, missed sequestration, methane fluxes, and dinitrogen monoxide emissions.Results and discussionOur estimated LUC emissions from mangrove deforestation resulted in 124 t CO2 ha−1 year−1, assuming IPCC’s recommendations of 1 m of soil loss, and 96% carbon oxidation. In addition to this, 1.25 t of carbon would no longer be sequestered annually. Discounted over 20 years, this resulted in total LULUC emissions of 129 t CO2 ha−1 year−1 (CV = 0.441, lognormal distribution (ln)). Shrimp farms in the Mekong Delta, however, can today operate for 50 years or more, but are 1.5 m deep (50% oxidation). In addition to this, Asian tiger shrimp farming in mixed mangrove concurrent farms (the only type of shrimp farm that resulted in mangrove deforestation since 2000 in our case study) resulted in 533 kg methane and 1.67 kg dinitrogen monoxide per hectare annually. Consequently, the LULUC GHG emissions resulted in 184 and 282 t CO2-eq t−1 live shrimp at farm gate, using mass and economic allocation, respectively. These GHG emissions are about an order of magnitude higher than from semi-intensive or intensive shrimp farming systems. Limitations in data quality and quantity also led us to quantify the uncertainties around our emission estimates, resulting in a CV of between 0.4 and 0.5.ConclusionsOur results reinforce the urgency of conserving mangrove forests and the need to quantify uncertainties around LULUC emissions. It also questions mixed mangrove concurrent shrimp farming, where partial removal of mangrove forests is endorsed based upon the benefits of partial mangrove conservation and maintenance of certain ecosystem services. While we recognize that these activities limit the chances of complete removal, our estimates show that large GHG emissions from mangrove LULUC question the sustainability of this type of shrimp farming, especially since mixed mangrove farming only provide 5% of all farmed shrimp produced in Vietnam.

Use of carbon–oligomer filler prepared from rubbers reclaimed with dinitrogen monoxide as a component of elastomer compounds

Samples of carbon–oligomer filler prepared by ketonization of tire rubber crumb with dinitrogen monoxide were characterized. The effect of the oligomeric component of the filler on the kinetic parameters of cross-linking in model compounds was determined. A study of the main rheological and physicomechanical properties of elastomer compounds based on butadiene–α-methylstyrene rubber containing carbon–oligomer filler demonstrated the possibility of using it as a component of polyfunctional action.

Cyclic gas-phase heterogeneous process in a metal-organic framework involving a nickel nitrosyl complex.

The cubic metal-organic framework MFU-4l ([Zn5Cl4(BTDD)3], H2-BTDD = bis(1H-1,2,3-triazolo[4,5-b],[4',5'-i])dibenzo[1,4]dioxin) featuring large pore apertures can be modified post-synthetically via partial or complete substitution of peripheral metal sites and chloride side-ligands, thus opening a route towards a large variety of functionalized MOFs. In this way, Ni-MFU-4l-nitrite (or Ni-MFU-4l-NO2) with an analytically determined chemical composition [Zn2.6Ni2.4(NO2)2.9Cl1.1(BTDD)3], containing accessible Ni-NO2 units, was prepared. Ni-MFU-4l-NO2 undergoes selective heterogeneous gas-phase reduction by carbon monoxide at 350 °C, leading to formation of Ni-NO units at the peripheral sites of the MFU-4l framework (Ni-MFU-4l-NO). The crystallinity and porosity of the MFU-4l framework are completely retained upon this transformation. The so-formed nickel nitrosyl complex, showing high thermal stability, readily reacts with nitrogen monoxide at room temperature, producing Ni-NO2 units and dinitrogen monoxide (N2O). Hence, the reaction of Ni-MFU-4l-NO2 with CO followed by NO represents a cyclic process with an overall stoichiometry 2NO + CO → N2O + CO2, in which the Ni-MFU-4l framework serves as a catalyst. It can be considered as a model process for the removal of highly toxic NO and CO gases, which are converted to non-toxic CO2 and N2O. Diffuse reflectance infrared Fourier transform spectroscopic studies show that at least 10 cycles can be repeated. The framework's reactivity drops down by ca. 50% after 10 cycles, which is most likely due to the accumulation of highly reactive NO2 and N2O4 contaminants. Therefore, further investigations on characterizing reaction intermediates should be done in order to improve the catalyst's performance. Our results confirm the potential of MFU-4l frameworks as selective single-site catalysts for heterogeneous gas-phase transformations and provide a motivation for further studies.

Updated unit process data for coal-based energy in China including parameters for overall dispersions

Chinese coal power generation is part of the life cycle of most products and the largest single source for many emissions. Reducing these emissions has been a priority for the Chinese government over the last decade, with improvements made by replacing older power plants, improving thermal efficiency and installing air pollution control devices. In the present research, we aim to acknowledge these improvements and present updated unit process data for Chinese coal power. In the course of doing so, we also explore the implementation and interpretation of overall dispersions related to a generically averaged process, such as Chinese coal power. In order to capture geographical and temporal dispersions, updated unit process data were calculated for Chinese coal power at both a national and a provincial level. The updated unit process dataset was also propagated into life cycle inventory (LCI) ranges using Monte Carlo simulations, allowing for discrepancies to be evaluated against the most commonly used inventory database (ecoinvent) and overall dispersions to be shown for some selected provinces. Compared to ecoinvent, the updated dataset resulted in reductions with between 8 and 67 % for all evaluated inventory flows except for dinitrogen monoxide (N2O). However, interprovincial differences in emissions diverged with up to 250 %. A random outcome in a few Monte Carlo runs was inverted operators, where positive values became negative or the other way around. This is a known possible outcome of matrix calculations that needs to be better evaluated when interpreting propagated outcomes. The present manuscript provides recommendations on how to implement and interpret dispersions propagated into LCI results. In addition, updated and easily accessible unit process data for coal power plants averaged across China and for individual provinces are presented, with clear distinctions of inherent uncertainties, spread (variance) and unrepresentativeness. Recommendations are also provided for future research and software developments.

No laughing matter: the unmaking of the greenhouse gas dinitrogen monoxide by nitrous oxide reductase.

The gas nitrous oxide (N₂O) is generated in a variety of abiotic, biotic, and anthropogenic processes and it has recently been under scrutiny for its role as a greenhouse gas. A single enzyme, nitrous oxide reductase, is known to reduce N₂O to uncritical N₂, in a two-electron reduction process that is catalyzed at two unusual metal centers containing copper. Nitrous oxide reductase is a bacterial metalloprotein from the metabolic pathway of denitrification, and it forms a 130 kDa homodimer in which the two metal sites CuA and CuZ from opposing monomers are brought into close contact to form the active site of the enzyme. CuA is a binuclear, valence-delocalized cluster that accepts and transfers a single electron. The CuA site of nitrous oxide reductase is highly similar to that of respiratory heme-copper oxidases, but in the denitrification enzyme the site additionally undergoes a conformational change on a ligand that is suggested to function as a gate for electron transfer from an external donor protein. CuZ, the tetranuclear active center of nitrous oxide reductase, is isolated under mild and anoxic conditions as a unique [4Cu:2S] cluster. It is easily desulfurylated to yield a [4Cu:S] state termed CuZ (*) that is functionally distinct. The CuZ form of the cluster is catalytically active, while CuZ (*) is inactive as isolated in the [3Cu(1+):1Cu(2+)] state. However, only CuZ (*) can be reduced to an all-cuprous state by sodium dithionite, yielding a form that shows higher activities than CuZ. As the possibility of a similar reductive activation in the periplasm is unconfirmed, the mechanism and the actual functional state of the enzyme remain under debate. Using enzyme from anoxic preparations with CuZ in the [4Cu:2S] state, N2O was shown to bind between the CuA and CuZ sites, suggesting direct electron transfer from CuA to the substrate after its activation by CuZ.

Interaction of Small Gases with the Unsaturated Metal Centers of the HKUST-1 Metal Organic Framework

The interactions of CO, CO2, OCS, SO2, NO, NO2, N2O, NH3, PH3, and other small molecules with the undercoordinated metal centers of the HKUST-1 metal organic framework are studied by means of density functional theory. These molecules are potentially harmful for humans and the environment and are widely studied because of their spectroscopic properties. In this work, the energetic and vibrational characteristics of the adsorbed species are calculated. Adsorption energies on the Cu2+ sites of the paddlewheel have been calculated, and the order is: NH3 > H2O > PH3 > H2S > SO2 > CO ∼ OCS ∼ CO2 ∼ NyOx > N2 > O2. The results show that the interactions can be classified into three categories: (1) weak physisorption, (2) polarization and electrostatics, and (3) strong acid–base. Moreover, interesting vibrational properties are calculated especially for carbonyl sulfide and dinitrogen monoxide, which can be bound via two different configurations on the metal atoms. The vibrational modes are shifting in different ...

High productivity chromatographic separations on monolithic capillary columns

The productivity of monolithic capillary columns based on silica gel and polymers of different polarities (divinylbenzene and ethyleneglycol dimethacrylate) is investigated using a model mixture of light hydrocarbons. It is shown that the productivity of a column is noticeably affected by the type of gas carrier. The highest productivity is observed when using carbon dioxide or dinitrogen monoxide as the gas carrier. The lowest productivity is observed when uisng hydrogen or helium.

Study of Continuous Monitoring of Dinitrogen Monoxide at Domestic Waste Landfill Sites

Study of Continuous Monitoring of Dinitrogen Monoxide at Domestic Waste Landfill Sites