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Catalysts consisting of highly dispersed copper on a mesoporous ZrO2 support were synthesised via a one-pot sol-gel synthesis and were tested for the selective catalytic reduction of NOx by NH3. The copper dispersion was investigated by XRD and TEM, which showed no discernible copper oxide particles up to 6 wt% Cu, while they were detected at 15 wt% Cu., NH3 adsorption and the SCR reaction were followed in situ by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) on mesoporous ZrO2 and on one-pot synthesized 3 wt% Cu/ZrO2. Cu was found to improve the NH3 adsorption capacity of the catalyst by enhancing the Lewis functionality., The catalysts were efficient for SCR at low temperature, at 150 degrees C 75% of NO was converted over 6 wt% Cu/ ZrO2 at water-free conditions. Increasing the copper loading while maintaining the dispersion improved NOx conversion.

This study reviews the available and most commonly used methods of gas deodorization. Comparing various methods of odor removal, undoubtedly biological methods of pollution degradation have an advantage over others—chemical and physical. This advantage is manifestedmainly in ecological and economic terms. The possibility of using biological methods to remove H2S and NH3, as the most common emitted by the municipal sector companies, was analyzed in terms of their removal efficiency. The method of bio-purification of air in biotrickling filters is more advantageous than the others, due to the high effectiveness of VOCs and odors degradation, lack of secondary pollutants, and economic aspects—it is a method competitive to the commonly used air purification method in biofilters.

We conducted a randomized trial of portable HEPA air cleaners with pre-filters designed to also reduce NH3 in non-smoking homes of children age 6-12 with asthma in Yakima Valley (Washington, USA). Participants were recruited through the Yakima Valley Farm Workers Clinic asthma education program. All participants received education on home triggers while intervention families additionally received two HEPA cleaners (child's sleeping area, main living area). Fourteen-day integrated samples of PM2.5 and NH3 were measured at baseline and one-year follow-up. We fit ANCOVA models to compare follow-up concentrations in HEPA versus control homes, adjusting for baseline concentrations. Seventy-one households (36 HEPA, 35 control) completed the study. Most were single-family homes, with electric heat and stove, A/C, dogs/cats, and mean (SD) 5.3 (1.8) occupants. In the sleeping area, baseline geometric mean (GSD) PM2.5 was 10.7 (2.3) µg/m3 (HEPA) versus 11.2 (1.9) µg/m3 (control); in the living area, it was 12.5 (2.3) µg/m3 (HEPA) vs. 13.6 (1.9) µg/m3 (control). Baseline sleeping area NH3 was 62.4 (1.6) µg/m3 (HEPA) vs. 65.2 (1.8) µg/m3 (control). At follow-up, HEPA families had 60% (95% CI, 41%-72%; p < 0.0001) and 42% (19%-58%; p = 0.002) lower sleeping and living area PM2.5 , respectively, consistent with prior studies. NH3 reductions were not observed.

Quantitative data comparing iron and cobalt based catalysts for the Fischer-Tropsch synthesis (FTS) are scarce due to the fact that these two kinds of catalysts typically utilize different process conditions. This paper focuses on studying the catalytic behavior of two highly active iron and cobalt based research catalysts at clean conditions and during poisoning with common syngas contaminants. The catalyst activity and selectivity at identical conditions, the CO conversion effect, and the effect of poisons on iron and cobalt catalysts were systematically explored in a quantitative manner. At a set of identical FTS conditions, the cobalt catalyst was 2.5 times as active as the iron catalyst with higher CH4 and C5+ selectivities but much less olefins and lower CO2 selectivity. Cobalt based catalysts are more susceptible to deactivation by oxidation at high CO conversions (e.g. > 80%) due to the high partial pressure of water (PH2O) in the reactor, while the iron catalyst can be stabilized at a high conversion level. Under clean FTS conditions, the cobalt catalysts displayed a more pronounced CO conversion effect on stability and selectivity; on the other hand, a combination of effects (i.e. from CO conversion and the nature of the catalyst) were observed for the iron catalysts. The sensitivities of the Fe and Co catalysts to the typical contaminants (i.e., H2S and NH3) present in the syngas derived from coal, natural gas or biomass were compared. Iron and cobalt catalysts exhibited similar resistance to the H2S poison (i.e. threshold levels 25–50 ppb), but the iron catalyst was found to be much more resistant to ammonia than the cobalt catalyst (i.e., threshold levels of 80 ppm and 45 ppb, respectively). Co-feeding 150–200 ppm ammonia lowered CH4 selectivity and 2-olefin content (suppressing secondary reactions of 1-olefin) on both types of catalysts. In contrast, co-feeding up to 1 ppm H2S significantly increased CH4 formation only on cobalt catalysts but had a minor effect on CH4 selectivity with iron catalysts. It increased 2-olefin content (enhanced secondary reactions of 1-olefin) regardless of catalyst type. H2S and NH3 have different impacts on H2, CO adsorption, and the formation of sulfur and nitride compounds have been proposed to explain these dissimilar effects.

Gas sensors have played a critical role in healthcare, atmospheric environmental monitoring, military applications and so on. In particular, flexible sensing devices are of great interest, benefitting from flexibility and wearability. However, developing flexible gas sensors with a high sensitivity, great stability and workability is still challenging. In this work, multi-walled carbon nanotubes (MWCNTs) were grown on polydimethylsiloxane (PDMS) films, which were further modified with polyaniline (PANI) using a simple chemical oxidation synthesis. The superior flexibility of the PANI-MWCNTs/PDMS film enabled a stable initial resistance value, even under bending conditions. The flexible sensor showed excellent NH3 sensing performances, including a high response (11.8 ± 0.2 for 40 ppm of NH3) and a low limit of detection (10 ppb) at room temperature. Moreover, the effect of a humid environment on the NH3 sensing performances was investigated. The results show that the response of the sensor is enhanced under high humidity conditions because water molecules can promote the adsorption of NH3 on the PANI-MWCNTs/PDMS films. In addition, the PANI-MWCNTs/PDMS film sensor had the abilities of detecting NH3 in the simulated breath of patients with kidney disease and the freshness of shrimp. These above results reveal the potential application of the PANI-MWCNTs/PDMS sensor for monitoring NH3 in human breath and food.

A sustainable model of combined organic–inorganic fertilizer application for high maize yields and environmental health is important for food security. The short-term combined application of organic and inorganic fertilizers can improve crop yields; however, the effect of different proportions of organic and inorganic fertilizers on the maize yield and nitrogen gas emissions in a long time series has not been reported. In this study, field experiments and DeNitrification-DeComposition (DNDC) model simulations were used to study the long-term effects of substituting inorganic fertilizers with organic fertilizers on crop yields and nitrogen-containing gas emissions. Six treatments were included: no nitrogen (CK); urea (U1); and 25%, 50%, 75%, and 100% of the urea N substituted by organic fertilizers (U3O1, U1O1, U1O3, and O1, respectively). The DNDC model was calibrated using the field data from the U1 treatment from 2018 to 2020 and was validated for the other treatments. The results showed that this model could effectively simulate crop yields (e.g., nRMSE < 5%), soil NH3 volatilization, and N2O emissions (nRMSE < 25%). In addition, long-term (26 years) simulation studies found that the U1O1 treatment could considerably increase maize yields and ensure yield stability, which was 15.69–55.31% higher than that of the U1 treatment. The N2O, NH3, and NO emissions were in the descending order of U1 > U3O1 > O1 > U1O3 > U1O1, and the total nitrogen-containing gas emissions from the U1O1 treatment decreased by 53.72% compared with the U1 treatment (26 years). Overall, substituting 50% of inorganic nitrogen with organic nitrogen could maintain the high yield of maize and reduce emissions of nitrogen-containing gases, constituting a good mode for the combined application of organic–inorganic nitrogen in this area.

Nutrient conservation and greenhouse gas emission control during composting have attracted much attention. This study investigated the effects of different amounts of superphosphate (SSP) on greenhouse gas emissions and the dynamic changes in nutrients during pig manure composting. Six treatments were used: pig manure + straw (S1), pig manure + straw + 3% SSP (S2), pig manure + straw + 6% SSP (S3), pig manure (M1), pig manure + 3% SSP (M2), and pig manure + 6% SSP (M3). The results showed that the addition of SSP had no negative effect on organic matter composting, and all treatments met the requirement of being harmless. The contents of TN, TP, and TK increased during the composting process, but the content of organic matter decreased gradually. At the end of composting, the total nutrient content of the pig manure + straw + 6% SSP treatment was the highest (6.39%), while that of the pig manure treatment was the lowest (4.47%). The NH3 emission reductions with additions of 3% and 6% SSP were 37.13~56.80% and 45.63~77.04%, respectively, compared with the pig manure treatment. The treatment addition of 6% SSP reduced CO2 emissions by 10.3~20.1% compared with the pig manure treatment. The pig manure + 6% SSP treatment resulted in the lowest cumulative emission of N2O, which was 79.75% lower than that of the pig manure treatment. For the cumulative emission of CH4, the treatment of pig manure + 6% SSP was at least 23.14 mg·kg−1 and had the lowest global warming potential. In conclusion, adding 6% SSP to pig manure compost effectively reduces NH3 and CO2 emissions and improves compost quality.

CeNbTi catalyst was poisoned in different sulfur poisoning atmospheres at 300 °C for 6 h and then was evaluated for selective catalytic reduction (SCR) of NOx with NH3. The catalyst deactivation upon SO2 exposure was effectively inhibited in the presence of NH3. Temperature-programmed decomposition (TPD) analyses were applied to identify deposit species on the poisoned catalysts by comparison with several groups of reference samples. Diffuses reflectance infrared Fourier transform spectroscopy (DRIFTS) over CeNbTi catalysts with different poisoning pretreatments and gas purging sequences were designed to investigate the roles of NH3 in the removal of surface sulfites and sulfates. More ammonium sulfates including ammonium bisulfate and ammonium cerium sulfate were generated instead of inert cerium sulfate in these conditions. The mechanisms about the formation and transformation of surface deposits upon sulfur poisoning w/wo NH3 were explored, which provided a basis for developing Ce-based mixed oxides as SCR catalysts for stationary sources.

The latest generation of heavy-duty vehicles (Euro VI step E) have to respect low emission limits both in the laboratory and on the road. The most challenging pollutants for diesel vehicles are NOx and particles; nevertheless, NH3 and N2O need attention. In this study, we measured regulated and unregulated pollutants of a Euro VI step E Diesel vehicle. Samples were taken downstream of (i) the engine, (ii) the Diesel oxidation catalyst (DOC) and catalyzed Diesel particulate filter (cDPF), and (iii) the selective catalytic reduction (SCR) unit for NOx with an ammonia slip catalyst (ASC). In addition to typical laboratory and real-world cycles, various challenging tests were conducted (urban driving with low payload, high-speed full-load driving, and idling) at 23 °C and 5 °C. The results showed high efficiencies of the DOC, DPF, and SCR under most testing conditions. Cold start cycles resulted in high NOx emissions, while high-temperature cycles resulted in high particle emissions. The main message of this study is that further improvements are necessary, also considering possible reductions in the emission limits in future EU regulations.

Ammonia (NH3) emissions resulting from the field application of livestock slurry has both negative human health and environmental impacts. However, decreasing the exposed surface area (ESA) of slurry upon application can reduce NH3 volatilization by limiting its atmospheric exposure. In the present study, three strategies for depositing slurry within a growing crop were studied, including: 1. standard trailing hoses (SAhose), 2. trailing shoes (SAshoes), and 3. the combination of rigid tines and trailing shoes (SAtines+shoes). Application methods interact with the soil to varying degrees and were evaluated within the context of contemporary weed management practices, namely in cereals receiving inter-row hoeing. SAhose, SAshoes, and SAtines+shoes were compared in three coinciding experiments that assessed slurry ESA, NH3 emissions, and crop and weed effects. SAtines+shoes resulted in smallest ESA, 70–72% and 61–66% less than SAhose and SAshoes, respectively. However, in only one of three site–years did SAshoes and SAtines+shoes reduce NH3 emissions compared to SAhose, by 46% and 29%, respectively. Crop yields, nitrogen (N) accumulation in crop biomass, and intra-row weed biomass were unaffected by the placement method. In heavily crusted soils, the SAtines+shoes prototype worked well; however, the functional differences among placement strategies were not great enough to detect crop and NH3 effects.

The purpose of this study was to evaluate the performance of laboratory-scale biotrickling filters (BTFs) packed with composite filler and pine bark filler under different operating conditions in purifying mixed gas containing H2S and NH3. The composite filler was prepared with modified activated carbon and loaded with functional microbes, using the microbial immobilization technology combined with a nutrient sustained-release composite filler. The results showed that the composite filler could better adapt to low empty bed retention time (EBRT) and high inlet concentration than the pine bark filler. When EBRT was 40 s and the inlet load was 41 g/m3·h, the NH3 removal efficiency of the composite filler was kept above 80%, and when the inlet load was 61.5 g/m3·h, it could be stabilized at about 60%. When EBRT exceeds 34 s, the H2S removal efficiency of the two BTFs was maintained at 100%. Yet, when EBRT was 34 s, the H2S removal efficiency of the bark filler BTF dropped to

Reducing the production of odor during swine breeding has attracted attention. Ammonia (NH3) and hydrogen sulfide (H2S) contributed to the odor emissions from swine breeding because NH3 emissions are high and hydrogen sulfide (H2S) has a low odor threshold. Sodium butyrate reduces the odor emissions caused by NH3 and H2S, but the corresponding mechanism is unclear. After mixing the feces of six fattening pigs, the mixture was used to process in vitro fermentation experiment. The purpose was researching the effect of sodium butyrate reduced NH3 and H2S emissions in swine cecal contents. The control group was denoted CK, and the treatment groups with different sodium butyrate concentrations (0.015%, 0.030% and 0.150%) were denoted L, M and H. The NH3, H2S, total gas production and physicochemical indexes were measured, and the bacterial communities in the fermented product were analyzed by 16 S rDNA sequencing. The results showed that group M reduced NH3, H2S and total gas production by 17.96%, 12.26% and 30.30%, respectively. Sodium butyrate promoted SO42- accumulation and lowered the pH. Importantly, sodium butyrate decreased the relative abundance of bacteria positively correlated with NH3 and H2S production, but increased the negatively correlated ones. Proteobacteria made a greater contribution to reducing emissions than did other bacterial phyla. Our results showed that adding 0.030% sodium butyrate can significantly reduce NH3 and H2S production, which occurred via alterations in the physicochemical indicators to adjust the abundance of the bacteria related to odor production, including Proteobacteria.

As one of the regions with intensive agriculture and rapid economic development in China, North China also has a high nitrogen (N) deposition. This study characterized the spatial pattern of N deposition in North China, combining the tropospheric columns from satellite measurements and the simulated profiles from an atmospheric chemistry transport model. The total N deposition fluxes ranged from 16.3 to 106.5 kg N ha−1 yr−1, with an average of 54.5 ± 17.2 kg N ha−1 yr−1. The high values were concentrated in urban and farmland areas, while low values were found in forests and grasslands with less human activities. Of the total N deposition, 36% was deposited via precipitation, 12% was deposited through dry particulate deposition, and the remaining 52% was comprised of dry gaseous deposition. For the seasonal variation of dry deposition, gaseous HNO3 and particulate NO3− were higher in winter and autumn, but lower in spring and summer. In contrast, gaseous NH3 and particulate NH4+ were higher in spring and summer, but lower in winter and autumn. This is possibly caused by the seasonal differences in emission intensity between NOx and NH3 emission sources. The gaseous NO2 deposition did not show strong seasonal variation. The wet deposition was mainly affected by precipitation, with high values in summer and low values in winter. This research provides an objective spatial perspective and insight into the total N deposition in North China.

Mechanisms of alloy degradation in a fireside N-S-O-C-H-Cl-Na-K atmosphere at 880 degrees C were elucidated using SEM-EDS, chemical equilibrium calculations, and XRD. Alloys 310S, 800H/HT, and 600 were studied after 0, 8000, and 16,000 h exposure in a boiler co-firing biomass waste. For 310S and 800H/HT it was shown that nitrogen formed internal Cr nitrides lowering the Cr activity and inhibiting internal alloy Cr permeation, and that NaCl and Na2SO4 reacted with Cr oxide to form chromate and to accelerate the S and the Cl pickup. Alloy 600 showed no nitride or major chromate formation. Bio4Energy

Atmospheric ammonia (NH3) released from agriculture is contributing significantly to acidification and atmospheric NH3 may have on human health is much less readily available. The potential direct impact of NH3 on the health of the general public is under-represented in scientific literature, though there have been several studies which indicate that NH3 has a direct effect on the respiratory health of those who handle livestock. These health impacts can include a reduced lung function, irritation to the throat and eyes, and increased coughing and phlegm expulsion. More recent studies have indicated that agricultural NH3 may directly influence the early on-set of asthma in young children. In addition to the potential direct impact of ammonia, it is also a substantial contributor to the fine particulate matter (PM2.5) fraction (namely the US and Europe); where it accounts for the formation of 30% and 50% of all PM2.5 respectively. PM2.5 has the ability to penetrate deep into the lungs and cause long term illnesses such as Chronic Obstructive Pulmonary Disease (COPD) and lung cancer. Hence, PM2.5 causes economic losses which equate to billions of dollars (US) to the global economy annually. Both premature deaths associated with the health impacts from PM2.5 and economic losses could be mitigated with a reduction in NH3 emissions resulting from agriculture. As agriculture contributes to more than 81% of all global NH3 emissions, it is imperative that food production does not come at a cost to the world's ability to breathe; where reductions in NH3 emissions can be easier to achieve than other associated pollutants. Department of Agriculture, Food and the Marine

Das Verständnis der katalytischen Aktivität und der lokalen Strukturen der aktiven Zentren spielt eine wichtige Rolle in der Verbesserung der Effizienz industrieller Prozesse und der weiteren Etablierung nachhaltiger chemischer Methoden. Von besonderem Interesse sind hierbei Bindungsaktivierungs- sowie isotrope Austauschreaktionen, welche als Vergleichreaktionen zur Evaluierung der Katalysatoren verwendet werden. Die hierbei ermittelten standardisierten Kennzahlen, wie die „turn over frequency“ oder die Aktivierungsenergie geben verlässliche Einblicke in das makroskopische System. Für heterogene Katalysatoren, wie „high surface“-Aluminiumtrifluorid (HS-AlF3) und Aluminiumchlorofluorid, mit 2-8 % Chlor (ACF), kann die Aktivität der aktiven Zentren über Adsorptionsexperimente von Testmolekülen, wie Kohlenstoffmonoxid und Ammoniak erfolgen. Hierbei können experimentelle und theoretische Daten über die Stärke der Adsorption sowie die Frequenzverschiebung spezifischer Molekülschwingungen gesammelt werden. Die experimentellen Untersuchungen werden hierbei durch die theoretischen Betrachtungen der Wechselwirkungen zwischen der katalytischen Oberfläche und der Edukte unterstützt. Die strukturellen Änderungen im System und mögliche Reaktionspfade werden hierbei von theoretischer Seite modelliert. In der vorliegenden Arbeit wird die PBE basierte Dichtefunktionaltheorie inklusive Dispersionskorrektur nach Grimme genutzt, um die Wechselwirkung von verschiedenen Modellstrukturen der aktiven Zentren von -AlF3 und der chlorierten Varianten mit ausgewählten Molekülen zu untersuchen. Hierzu werden die Testmoleküle Kohlenstoffmonoxid und Ammoniak auf den Modellstrukturen mit drei-, vier- und fünffach koordinierten Aluminiumzentren adsorbiert und die Verschiebung der Schwingungsfrequenzen berechnet. Im Anschluss werden die theoretischen Ergebnisse mit experimentellen Daten verglichen. In experimentellen Untersuchungen konnte gezeigt werden, dass der ACF Katalysator gute Ergebnisse in Hydrofluorinierungsreaktionen zeigt, wobei die Aktivität durch Zusatz von Triethylsilan und Triethylgerman weiter gesteigert werden kann. Aufgrund dieser Beobachtung werden zusätzliche Modellreaktionen mit Alkanen, Silanen und Germanen durchgeführt. Die erhaltenen Adsorptionsstrukturen werden genutzt, um die Dissoziationen der C-H, Si-H und Ge-H Bindungen zu betrachten, woraus thermodynamische und kinetische Eigenschaften abgeleitet werden. Hierbei werden die homologen Reihen von Methan über Isopropan und Isobutan sowie die Analoga der Silane und Germane untersucht. Als Abschluss wird die H/D-Austauschreaktion zwischen Methan und Benzol auf der Modelloberfläche des ACF-Katalysators untersucht, wobei der Gesamtprozess modelliert wird. Es wird deutlich, dass die Position von oberflächennahen Chlorsubstitutionen in AlF-Systemen einen signifikanten Einfluss auf die Aktivität der aktiven Zentren hat., An understanding of the activity and interactions at local structures of catalysts plays an important part in the improvement of the chemical efficiency and the corresponding ´´green chemistry´´ approaches. The comparison of different catalyst types is carried out via intrinsic data of their performence in various reactions of the catalyst, like bond activation reactions or isotropic exchange reactions. For heterogeneous catalysts like „high surface“-aluminiumtrifluorid (HS-AlF3) and aluminiumchlorofluorid (ACF) the activity of the active centers can be determined in experiments and first principle calculations via the adsorption of different probe molecules and the corresponding change in the vibrational frequency against the frequency of the free molecules. Additionally various reactions like bond activation reactions and isotropic exchange reactions can be used within theoretical approaches to gain insigth of detailled reaction pathways and structural changes of the educts due to the surface interaction. Within this thesis PBE based density functional theory with Grimme dispersion correction is used to investigate various interactions of the model surfaces of -AlF3 and their chlorinated variants with selected small molecules to compare the collected data with experimental results. Within these comparisons the model surfaces are verified. At first the probe molecules CO and NH3 are adsorbed at the model surfaces with three-, four- and fivefold coordinated aluminium centers of the aluminiumchlorofluoride catalyst based on the -AlF3 structure to investigate the corresponding frequency shifts of the molecule vibrations, which will be compared to experimental data. In additional steps the activity of the model surfaces will be investigated in bond activation reactions. It is known that especially triethylsilane and triethylgermane are improving the activity of the ACF catalyst in hydroflourination reactions, where they are acting as hydrogen sources. To observe the interaction of these compounds with the model surfaces, absorption energies of small alkanes, silanes and germanes and mininmum energy pathways of the C-H, Si-H and Ge-H bond dissociation reaction are determined. This approach yields thermodynamical and kinetic properties of various model surfaces and can be compared to experiments. Within these investigations the homologous series of methane, isopropane, isobutane and their silane and germane analogons are investigated. Finally the hydrogen exchange reaction between methane and benzene at the ACF model surfaces is investigated by the simulation of the overall process on the catalyst surface. It is shown that the presence and the position chlorine at the surface have a great influence on the activity of the catalyst.

In the past two decades, metal fluorides have gained importance in the field of heterogenous catalysis of bond activation reaction, e.g., hydrofluorination. One of the most investigated metal fluorides is AlF3. Together with its chlorine-doped analogon aluminiumchlorofluoride (AlClxF3���x, x = 0.05���0.3; abbreviated ACF), it has attracted much attention due to its application in catalysis. Various surface models for ��-AlF3 and their chlorinated analogues (as representatives of amorphous ACF) are investigated with respect to their Lewis acidity of the active centres. First-principle density functional theory (DFT) methods with dispersion correction are used to determine the adsorption structure and energy of the probe molecules CO and NH3. The corresponding vibrational frequency shift agrees well with the measured values. With this insight we predict the local structure of the active sites and can clarify the importance of secondary interactions to the local anionic surrounding of the catalytic site.

Received: January 28th, 2021 ; Accepted: May 26th, 2021 ; Published: August 24th, 2021 ; Correspondence: arnis.lenerts@llu.lv With the production of grain and livestock–derived agricultural commodities increasing, the agricultural sector has become one of the main sources of ammonia (NH3) emissions in Latvia. In 2018, the agricultural sector contributed to 83% of the total NH3 emissions originated in Latvia (15.46 kt) (LIIR 2020). The EU has already put in place measures to control NH3 emissions. This includes the EU target of reducing ammonia emissions by 21% by 2030 and sets out emission reduction commitments for Latvia. Considering Latvia’s indicative reduction target, the NH3 emission reductions need to be achieved by 2030 (Directive 2016/2284) so that the emissions do not exceed the 2005 level (11.33 kt). Implementing no mitigation measures, Latvia has projected agricultural sector NH3 emissions to be 32.4% higher than those in 2005, and therefore the mitigation of the NH3 emissions from agriculture is important. The research aims to estimate cost-effective NH3 emission reduction measures in agriculture in Latvia. The results of the research represent a marginal abatement cost curve (MACC) analysis, in which we have quantified the potential for reduction for selected NH3 emission mitigation measures in Latvia. A list of the measures has been established taking into account the experience of good agricultural practices in the reduction of NH3 emissions (UN, 2014) and of other European countries as well. The calculations carried out allowed us to group the measures according to their priorities: measures that are cost-effective and with high potential for reduction of NH3; measures that are cost-effective but with low NH3 emission reduction potential; measures that are not cost-effective but with high potential for reduction of NH3; measures that are not cost-effective and with low potential for reduction of NH3. The estimated cumulative (total) reduction of NH3 emissions in Latvian agriculture by 2030, with the implementation of the measures analysed, is equal to 20.08 kt.

Compressed natural gas (CNG) and liquefied petroleum gas (LPG) are included in the group of promoted transport fuel alternatives in Europe. Most studies on emissions factors are based on old technology CNG and LPG fueled vehicles. Furthermore, there are not many data at low ambient temperatures, on-road driving, or unregulated pollutants, such as ammonia (NH3). In this study we measured the emissions of one Euro 6b CNG light commercial vehicle, one Euro 6b and one Euro 6d-Temp bi-fuel LPG passenger car, one Euro 6d-Temp bi-fuel CNG passenger car, and four Euro 6d-Temp CNG passenger cars. Tests included on-road testing and worldwide harmonized light vehicles test cycles (WLTC) in the laboratory with cold and hot engine, at 23 °C and −7 °C. The results showed 10–23% CO2 savings in gas modality compared to gasoline, lower CO and particle number emissions, and relatively similar total and non-methane hydrocarbons and NOx emissions. The ammonia emissions were high for all vehicles and fuels; higher than gasoline and diesel vehicles. The results also showed that, following the introduction of the real-driving emissions regulation, even though not applicable to the examined vehicles, Euro 6d-Temp vehicles had lower emissions compared to the Euro 6b vehicles.

De gemeten concentraties ammoniak in de lucht zijn tussen 2005 en 2014 licht gestegen. Landelijk gezien bedraagt de stijging circa 1,5 procent per jaar. De grootste stijgingen doen zich voor in het noorden en oosten van het land. Dit blijkt uit een rapportage van het RIVM waarin de trend in de gemeten concentraties ammoniak van 2005 tot en met 2014 wordt gepresenteerd. Dit is een onderdeel van de rapportage van onderzoek dat is uitgevoerd naar aanleiding van de Quick-scan naar het uiteenlopen van de trends van ammoniakemissies en -concentraties door de Commissie Deskundigen Meststoffenwet (CDM, september 2014). Voor deze rapportage zijn metingen uit het Meetnet Ammoniak in Natuurgebieden (MAN) en het Landelijk Meetnet Luchtkwaliteit (LML) gebruikt. In het MAN wordt sinds 2005 de maandgemiddelde ammoniakconcentratie in de lucht gemeten in Nederlandse Natura2000- gebieden. Dat wordt gedaan omdat de natuur in deze gebieden gevoelig is voor een toename van de hoeveelheid stikstof, waardoor de biodiversiteit afneemt. Het MAN is ingericht omdat de natuurgebieden nauwelijks vertegenwoordigd zijn in het LML. De metingen worden uitgevoerd voor het Programma Aanpak Stikstof (PAS). Zowel in het MAN als in het LML is in de onderzochte periode de ammoniakconcentratie gestegen. De uitstoot van ammoniak door de landbouw is de belangrijkste bron voor de concentratie van ammoniak in de lucht. Daarnaast is de concentratie afhankelijk van de weersomstandigheden en de chemische samenstelling van de atmosfeer. Als naar de emissiecijfers van ammoniak wordt gekeken (gerapporteerd op www.emissieregistratie.nl), dan is er over de periode 2005 tot en met 2013 een landelijke afname te zien. Deze daling is echter niet terug te zien in de metingen van het MAN en LML, ook niet wanneer de effecten van meteorologie en veranderingen in de chemie van de atmosfeer worden verrekend. Dit verschil is op dit moment nog onderwerp van verdere studie

De gemeten concentraties ammoniak in de lucht zijn tussen 2005 en 2014 licht gestegen. Landelijk gezien bedraagt de stijging circa 1,5 procent per jaar. De grootste stijgingen doen zich voor in het noorden en oosten van het land. Dit blijkt uit een rapportage van het RIVM waarin de trend in de gemeten concentraties ammoniak van 2005 tot en met 2014 wordt gepresenteerd. Dit is een onderdeel van de rapportage van onderzoek dat is uitgevoerd naar aanleiding van de Quick-scan naar het uiteenlopen van de trends van ammoniakemissies en -concentraties door de Commissie Deskundigen Meststoffenwet (CDM, september 2014). Voor deze rapportage zijn metingen uit het Meetnet Ammoniak in Natuurgebieden (MAN) en het Landelijk Meetnet Luchtkwaliteit (LML) gebruikt. In het MAN wordt sinds 2005 de maandgemiddelde ammoniakconcentratie in de lucht gemeten in Nederlandse Natura2000- gebieden. Dat wordt gedaan omdat de natuur in deze gebieden gevoelig is voor een toename van de hoeveelheid stikstof, waardoor de biodiversiteit afneemt. Het MAN is ingericht omdat de natuurgebieden nauwelijks vertegenwoordigd zijn in het LML. De metingen worden uitgevoerd voor het Programma Aanpak Stikstof (PAS). Zowel in het MAN als in het LML is in de onderzochte periode de ammoniakconcentratie gestegen. De uitstoot van ammoniak door de landbouw is de belangrijkste bron voor de concentratie van ammoniak in de lucht. Daarnaast is de concentratie afhankelijk van de weersomstandigheden en de chemische samenstelling van de atmosfeer. Als naar de emissiecijfers van ammoniak wordt gekeken (gerapporteerd op www.emissieregistratie.nl), dan is er over de periode 2005 tot en met 2013 een landelijke afname te zien. Deze daling is echter niet terug te zien in de metingen van het MAN en LML, ook niet wanneer de effecten van meteorologie en veranderingen in de chemie van de atmosfeer worden verrekend. Dit verschil is op dit moment nog onderwerp van verdere studie

Ammonia is a toxic compound to aquatic organisms and at high concentrations in water, it can cause various changes in the animal. Therefore, it becomes important to determine the tolerance of farmed aquatic animals for that substance. Thus, the aim of this study was to determine the mean lethal concentration (LC50-96 h) of un-ionized ammonia (NH3) in tambacu fingerlings (Colossoma macropomum x Piaractus mesopotamicus) in acute toxicity test. The fingerlings were exposed to ammonia at concentrations of: 0.09 (control); 0.54; 1.23; 2.52; 3.44 and 3.66 mg L-1 NH3, which were obtained from the application of NH4Cl. The test lasted 96 hours and mortalities were recorded over that period. The LC50 was determined by the Trimmed Spearman Karber statistical method. The LC50-96 h of non-ionized ammonia (NH3) for fingerlings of the tambacu hybrid was 1.63 mg L-1.

International audience; Estimating agriculture’s contribution to air pollution and global warming is needed to understand and limit its impacts on the environment and climate. It is equally important to estimate the capacity of agricultural practices to mitigate these emissions and to characterize atmospheric deposition and the impacts of air pollutants on agroecosystems. This chapter presents methods for measuring air pollutant concentrations, their fluxes at the soil-vegetation-atmosphere interface, and emissions from livestock facilities. Methods for measuring air concentrations are described with a focus on compounds emitted from or impacting agriculture (including forests): ammonia, nitrogen oxides, pesticides, volatile organic compounds including methane, abiotic and biotic particles, and ozone. The main methods for measuring emission and deposition fluxes of air pollutants between terrestrial surfaces, especially agroecosystems, and the atmosphere are described with a specific focus on the eddy covariance method as well as on emissions from livestock buildings. Then the general principles of source apportionment methods for estimating emissions spatial variability are presented. To address the questions on atmospheric chemistry, the methods used for measuring the reactivity of atmospheric compounds are presented. Finally, an insight is given on the developments of measurement methodologies to address new compounds and improve the sensors’ sensitivity and response time as well as provide estimates of spatial variability of concentrations and fluxes at larger scales.

Aim of study: Agricultural activities are the main source of volatilized ammonia (NH3). Maximum rates are reached within a few hours after slurry application. This study aimed to evaluate the influence of soil texture, tillage and slurry dry matter (DM) on NH3 volatilization.Area of study: Mediterranean semiarid environments (NE Spain).Material and methods: Ammonia volatilization from pig slurry directly applied on the soil surface was quantified in the laboratory, in soil samples from two experimental sites with different soil textures: silty loam and sandy loam. Field treatments consisted of two tillage management practices: till by disc-harrowing or no-till. At topdressing (cereal tillering), tillage treatments were combined with slurries of different DM contents applied onto the silty loam soil. Measurements were done for two cereal cropping seasons and during the period of maximum NH3 flux (12 h after slurry application). A photoacoustic analyzer was used.Main results: Slurry spreading at sowing resulted in low volatilization (0.7-9% of NH4+-N applied) as it also did at topdressing (0.3-1.4% of NH4+-N applied). At sowing, ammonia volatilization from high DM slurry (>7.5%) was significantly enhanced by no-till in both soils. At topdressing, this result was also found in records on silty loam soil. No differences were found between tillage systems when slurry of low DM content was applied, whatever the soil texture and application moment. Although NH3 volatilization was probably affected by the laboratory conditions, the comparisons between treatments were still valuable.Research highlights: Ammonia volatilization abatement can be improved (

The oxidation of ammonia was studied experimentally by monitoring the time history of the intermediate N2O species using laser absorption spectroscopy. Experiments were conducted in a shock tube for mixtures of NH3/O2 diluted in ∼96.7% Ar for equivalence ratios of 0.54, 1.03, and 1.84. The equivalence ratios were determined accurately using spectroscopic measurements of NH3 with another laser before each experiment. Experiments were performed at an average pressure of 1.2 atm and covered a temperature range of 1829 to 2198 K. For the same temperature, experiments revealed that increasing the equivalence ratio leads to less N2O formation. The time-history profiles showed that N2O is formed at the beginning of the experiments, mainly from the formed NO, until reaching a peak. The N2O is then fully consumed, mainly via its reaction with H-atom. Characteristic parameters, such as the N2O peak time and mole fraction, were extracted from the N2O profiles and compared with 15 recent NH3 kinetics models. The comparison revealed that none of the existing kinetics models were able to correctly predict both the peak N2O time and mole fraction together. Two of the models were selected to perform a chemical analysis, and an improvement of the predictive capability of one model is proposed. The N2O profiles reported herein are excellent validation targets that offer stringent constraints for the improvement of future NH3 kinetics models.

The Planck Catalogue of Galactic Cold Clumps provides an all-sky sample of potential star-forming regions based on the submillimeter emission of their dust content. Around 1000 of these Planck objects were mapped with the James Clerk Maxwell telescope in the submillimeter range during the SCOPE survey, identifying prestellar and protostellar dense clumps inside them. We used the Effelsberg 100 m telescope to observe the emission lines of the NH3 inversion transitions toward a sample of 97 dense objects in varying environments in order to assess the physical parameters of their gas content. We derive their temperature, density, and velocity dispersion, correlating the resulting parameters with the environmental and evolutionary characteristics of the targets and with regard to their distance and physical size. We examine the dependence of physical parameters on distance and Galactic position and compare the gas-based and dust-continuum-based temperatures and densities. Together with the presence of maser emission and higher inversion transitions of ammonia, we may differentiate between certain groups of targets, e.g., filamentary, protostellar clumps, and high-latitude, core-sized, starless sources.

NH3 adsorption and desorption behavior of a commercial Cu-chabazite (CHA) NH3 selective catalytic reduction (NH3-SCR) catalyst was studied in the presence and absence of H2O. NH3 uptake values at various adsorption temperatures were obtained during various steps of the adsorption and temperature-programmed desorption (TPD) experiments. Total NH3 uptake decreased from 4.6 to 1.6 g NH3/L catalyst when the adsorption temperature was increased from 50 to 300 degrees C. Three major adsorption sites for NH(3)adsorption could be identified and quantified using TPD experiments, namely loosely, moderately, and strongly bound NH3 with peak centers at around 147, 266, and 447 degrees C. The total NH3 uptake was significantly affected by the presence of H2O in the feed. This resulted in a significant uptake loss (nearly 60%) for the loosely bound NH3. Three single-site and one three-site model were developed and compared in terms of NH3 uptake and release. The effects of site density values and thermodynamic restrictions in one-site models were investigated. The model using site density values obtained during the TPD phase resulted in the best fit among one-site models. The three-site model, which uses site density values obtained using dry adsorption of NH3, best represented the experimental data., Ford Otomotiv San. A.Ş

This paper reports electrodeposition of the composite of Polyaniline-Poly(styrene sulfonate) (PANI-PSS) tubules with TiO2 nanoparticles (PANI-PSS/TiO2 tubules) by using cyclic voltammetry (CV) and demonstrates it as an electronic sensor device. By this method, dispersion of TiO2 particles is ubiquitous in PANI-PSS matrix as characterized by various electrochemical, microscopic (FEG-SEM, FEG-TEM) and spectroscopic (FTIR-IMG) techniques. Electronic properties of the device were explored by CV and in situ conductance measurements. In situ conductance was measured based on the liquid-ion-gated Field Effect Transistor (FET) using PANI-PSS/TiO2 tubules as a conductive channel. During in situ conductivity measurements, it was found that PANI-PSS/TiO2 composite showed a fast redox switching (conversion of the most resistive to the most conductive state of PANI) compared to PANI-PSS. FEG-SEM images showed that polymer was thicker in case of composite and likely to be more porous in nature. All these results, owing to the interaction of PANI-PSS with the TiO2 nanoparticles, were supported by the distinct behavior of composite PANI-PSS/TiO2 in ammonia solutions. Composite sensors showed a significant sensor response for lower concentrations of ammonia up to the ppt/ppb range (50 ppt, 100 ppt, 200 ppt, 10 ppb) based on a liquid-ion-gated FET. (C) 2018 Elsevier B.V. All rights reserved.

The chemical vapor deposition of hexagonal boron nitride layers from BCl3 and NH3 is highly beneficial for scalable synthesis with high controllability, yet multiple challenges such as corrosive reaction or by-product formation have hindered its successful demonstration. Here, we report the synthesis of polycrystalline hexagonal boron nitride (h-BN) layers on copper foil using BCl3 and NH3. The sequential pulse injection of precursors leads to the formation of atomically thin h-BN layers with a polycrystalline structure. The relationship between growth temperature and crystallinity of the h-BN film is investigated using transmission electron microscopy and Raman spectroscopy. Investigation on the initial growth mode achieved by the suppression of precursor supply revealed the formation of triangular domains and existence of preferred crystal orientations. The possible growth mechanism of h-BN in this sequential-pulsed CVD is discussed.

Reducing the effects of climate change is a key-point to achieve sustainable development. It is known that fertilizer application stimulates soil gaseous N losses, especially immediately after their application. In this shortterm incubation experiment, the effects of different chabazite zeolite amendments on soil gaseous emissions (CO2, N2O, NOx and NH3) were evaluated in high resolution as potential mitigation strategy for agricultural soils. Different soil-zeolite mixtures, including both natural and NH4 +-enriched chabazite zeolites, were incubated for 24 h both immediately after the application of urea fertilizer and without a further N input in order to carry out a high resolution investigation of soil CO2, N2O, NOx and NH3 fluxes, in comparison to an unamended soil. Immediate CO2, N2O, NOx and especially NH3 emissions after fertilizer application were generally reduced in soils amended with zeolites at natural state, indicating a potential valuable material for reducing soil C-N gaseous losses. On the other hand, the application of NH4 +-enriched zeolites lowered CO2 and N2O emissions, but very high NOx fluxes occurred during the first 24 h even without applying any further N input. NH3 emissions were higher in NH4 +-enriched zeolites amended soil, but if the amendment is performed without further N inputs, the emissions can be significantly lowered with respect to a conventional urea fertilization. Reducing the effects of climate change is a key-point to achieve sustainable development. It is known that fertilizer application stimulates soil gaseous N losses, especially immediately after their application. In this short-term incubation experiment, the effects of different chabazite zeolite amendments on soil gaseous emissions (CO2, N2O, NOx and NH3) were evaluated in high resolution as potential mitigation strategy for agricultural soils. Different soil-zeolite mixtures, including both natural and NH4+-enriched chabazite zeolites, were incubated for 24 h both immediately after the application of urea fertilizer and without a further N input in order to carry out a high resolution investigation of soil CO2, N2O, NOx and NH3 fluxes, in comparison to an unamended soil. Immediate CO2, N2O, NOx and especially NH3 emissions after fertilizer application were generally reduced in soils amended with zeolites at natural state, indicating a potential valuable material for reducing soil C-N gaseous losses. On the other hand, the application of NH4+-enriched zeolites lowered CO2 and N2O emissions, but very high NOx fluxes occurred during the first 24 h even without applying any further N input. NH3 emissions were higher in NH4+-enriched zeolites amended soil, but if the amendment is performed without further N inputs, the emissions can be significantly lowered with respect to a conventional urea fertilization.

This paper focuses on carbon capture in an Ultra Super Critical power plant. The technology selected for CO2 capture is based on cooled ammonia scrubbing in post-combustion mode, as recently investigated by the authors in another work. Here, a rate-based approach is adopted. In detail, a specific primary energy consumption for CO2 avoided (SPECCA) of 2.77 MJ/kgCO2 is calculated in case of 85% of CO2 capture, with an ultimate power plant efficiency of 37.27%.

The NH, SO and CO van der Waals complexes with imidazole are characterized using highly correlated ab initio methods. The aim is to compare the behavior of greenhouse effect gases and pollutants in the presence of imidazole for predicting the ability of new materials, such as Zeolite Imidazolate Frameworks (ZIF's), for CO capture, storage and gas filters. Imidazole is considered as the simplest model to study the nature of host-guest interactions in ZIF's. Hydrogen bonding plays an important role in these polar gas capture processes, leading to three equilibrium structures of the imidazole + NH, five of the imidazole + SO, and twelve of the imidazole + CO. Real harmonic frequencies confirm the minimum energy character of these geometries. The complexation processes carry out important changes in the charge distribution of the ring. Binding energies calculated with CCSD(T)-F12 theory predict a favored adsorption of ammonia with respect to CO. In this case, the formation of intramolecular bonds involving the unprotonated nitrogen is clearly favored energetically. The binding energy corresponding to the most stable structure I1A of SO is approximately twice of the corresponding value of CO. Carbon monoxide presents the largest number of possible equilibrium structures which assure its capture by solid ZIF's although binding energies are relatively low., This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Community Framework Program under grant n PIRSES-GA- 2012-31754, the FIS2013-40626-P and FIS2016-76418-P projects of the MINECO, Spain. The authors also acknowledge the COST Actions 1401 and 1405. S.D. acknowledges MAEC-ACID (Spain) for the grant.

The molecule is a spatial arrangement of atoms that make it up. This arrangement defines its geometric structure. Knowing the geometry and ways to describe to great advantage in studying the electronic structure of molecules as between geometric and electronic structure there is a close connection.

Air pollution is a global threat to human health especially spermatogenesis. Animal and epidemiological studies suggest that epigenetic factors can transmit the pathologies transgenerationally. Paternal epigenetic effects can greatly impact offspring health. In this study and together with our previous report, we found that H2S donor Na2S and/or NH3 donor NH4Cl diminished mouse fertility, decreased spermatozoa concentration and motility, and impaired spermatogenesis in three consequent generations (F0, F1, and F2). In the current study, we found that DNA methylation, histone methylation, and estrogen receptor alpha (ERα) were impaired by NH4Cl and/or Na2S in F0, F1, and F2 mouse testes. Moreover, NH4Cl and/or Na2S might act as environmental endocrine-disrupting chemicals to decrease estrogen and testosterone in mouse blood. It has been reported that ERα signaling is intertwined together with DNA methylation and histone methylation, which plays very important roles in spermatogenesis. These data together indicate that the transgenerational disruption in spermatogenesis by NH4Cl and/or Na2S may be through ERα-related DNA methylation and histone methylation pathways. Therefore, we strongly recommend that greater attention should be paid to NH3 and/or H2S contamination to minimize their impact on human health especially spermatogenesis.

Mo nitrogenase (N2ase) utilizes a two-component protein system, the catalytic MoFe and its electron-transfer partner FeP, to reduce atmospheric dinitrogen (N2) to ammonia (NH3). The FeMo cofactor contained in the MoFe protein serves as the catalytic center for this reaction and has long inspired model chemistry oriented toward activating N2. This field of chemistry has relied heavily on the detailed characterization of how Mo N2ase accomplishes this feat. Understanding the reaction mechanism of Mo N2ase itself has presented one of the most challenging problems in bioinorganic chemistry because of the ephemeral nature of its catalytic intermediates, which are difficult, if not impossible, to singly isolate. This is further exacerbated by the near necessity of FeP to reduce native MoFe, rendering most traditional means of selective reduction inept. We have now investigated the first fundamental intermediate of the MoFe catalytic cycle, E1, as prepared both by low-flux turnover and radiolytic cryoreduction, using a combination of Mo Kα highenergy-resolution fluorescence detection and Fe K-edge partial-fluorescence-yield X-ray absorption spectroscopy techniques. The results demonstrate that the formation of this state is the result of an Fe-centered reduction and that Mo remains redoxinnocent. Furthermore, using Fe X-ray absorption and 57Fe Mössbauer spectroscopies, we correlate a previously reported unique species formed under cryoreducing conditions to the natively formed E1 state through annealing, demonstrating the viability of cryoreduction in studying the catalytic intermediates of MoFe.

This work aims to analyse and compare the thermodynamic performance and size of two types of solid oxide fuel cell (SOFC)-based plants. The former is the conventional H2-fed plant based on SOFC with an oxygen-ion conducting electrolyte (SOFC-O), and the latter is based on SOFC using a proton-conducting electrolyte (SOFC-H). Thermodynamic analysis reveals that in the SOFC-H system, due to H2O formation at the cathode side, not only the anode concentration losses decreases, but also the partial pressure difference between H2 and H2O increases which leads to an increase in Nernst voltage compared to the SOFC-O system. Due to this, SOFC-H and SOFC-O based plants exhibit different performance in terms of the cell voltage, power, efficiency, stack outlet temperature and size of heat exchangers used for preheating the fuel and air. The results indicate, for current densities less than around 3,000 A/m2, the energy and exergy efficiencies of SOFC-H-based system are more than those of the SOFC-O-based plant. This results in reduced area of heat exchangers per unit power used in the SOFC-H-based plant as compared with the SOFC-O-based plant. In addition, the sensitivity analysis demonstrates that using thin cells in the SOFC stack is favourable for the SOFC-H-based plant.

International audience; In this paper, we describe a new flexible and robust NH3 retrieval algorithm from measurements of the Infrared Atmospheric Sounding Interferometer (IASI). The method is based on the calculation of a spectral hyperspectral range index (HRI) and subsequent conversion to NH3 columns via a neural network. It is an extension of the method presented in Van Damme et al. (2014a) who used lookup tables (LUT) for the radiance-concentration conversion. The new method inherits the advantages of the LUT-based method while providing several significant improvements. These include the following: (1) Complete temperature and humidity vertical profiles can be accounted for. (2) Third-party NH3 vertical profile information can be used. (3) Reported positive biases of LUT retrieval are reduced, and finally (4) a full measurement uncertainty characterization is provided. A running theme in this study, related to item (2), is the importance of the assumed vertical NH3 profile. We demonstrate the advantages of allowing variable profile shapes in the retrieval. As an example, we analyze how the retrievals change when all NH3 is assumed to be confined to the boundary layer. We analyze different averaging procedures in use for NH3 in the literature, introduced to cope with the variable measurement sensitivity and derive global averaged distributions for the year 2013. A comparison with a GEOS-Chem modeled global distribution is also presented, showing a general good correspondence (within ±3 × 1015 molecules.cm−2) over most of the Northern Hemisphere. However, IASI finds mean columns about 1–1.5 × 1016 molecules.cm−2 (∼50–60%) lower than GEOS-Chem for India and the North China plain.

International audience; CuxSiBEA zeolites (with x = 1–7.5 Cu wt %) prepared by a two-step postsynthesis method which consists in the first step of dealumination of parent BEA zeolite to obtain aluminum-free SiBEA support and then in the second step, of contacting the obtained material with an aqueous solution of copper nitrate, were used in this work as catalysts of SCR of NO with ammonia. XRD, TPR and FTIR investigations showed that up to 2 wt % of Cu was successfully incorporated into zeolite beta structure as framework mononuclear Cu(II). The FTIR of pyridine sorption revealed that the incorporation of copper into zeolite framework led to the creation of new Lewis acidic sites which were responsible for high activity of CuxSiBEA zeolite catalysts in SCR of NO with ammonia. The catalytic activity of CuxSiBEA in SCR of NO with ammonia used as a reducing agent strongly depends on the nature and environmental of copper in BEA structure. The Cu1.0SiBEA catalyst with predominantly framework Cu(II) was the most active and selective among the tested samples in wide temperature range. In contrast, the application of CuxSiBEA zeolite catalysts with higher Cu content (>than 2 wt % of Cu) containing a mixture of framework and extra-framework Cu(II) resulted in low NO conversion in SCR at high temperature range, as well as, the high concentration of undesired N2O in outgas stream. It indicates that octahedral Cu(II) and/or copper oxides present in extra-framework position of SiBEA zeolite promote at high temperature ammonia oxidation.

Molecules with hyperfine splitting of their rotational line spectra are useful probes of optical depth, via the relative line strengths of their hyperfine components.The hyperfine splitting is particularly advantageous in interpreting the physical conditions of the emitting gas because with a second rotational transition, both gas density and temperature can be derived. For HCN however, the relative strengths of the hyperfine lines are anomalous. They appear in ratios which can vary significantly from source to source, and are inconsistent with local thermodynamic equilibrium. This is the HCN hyperfine anomaly, and it prevents the use of simple LTE models of HCN emission to derive reliable optical depths. In this paper we demonstrate how to model HCN hyperfine line emission, and derive accurate line ratios, spectral line shapes and optical depths. We show that by carrying out radiative transfer calculations over each hyperfine level individually, as opposed to summing them over each rotational level, the anomalous hyperfine emission emerges naturally. To do this requires not only accurate radiative rates between hyperfine states, but also accurate collisional rates. We investigate the effects of different sets of hyperfine collisional rates, derived via the 'proportional method' and through direct recoupling calculations. Through an extensive parameter sweep over typical low mass star forming conditions, we show the HCN line ratios to be highly variable to optical depth. We also reproduce an observed effect whereby the red-blue asymmetry of the hyperfine lines (an infall signature) switches sense within a single rotational transition., Comment: 12 pages, 7 figures. Accepted for publication in MNRAS

MnOx-based catalysts supported at different loadings on TiO2 (2-10wt%) and H-ZM5 (2-20wt%) were tested for the NH3-SCR of NO in the temperature range 50-250°C. All catalysts showed enhanced activity at low temperature compared to conventional SCR catalyst. A detailed characterization of catalysts (BET, H2-TPR, NH3- and O2-TPD) revealed the predominance of MnO2, with an enhanced dispersion when supported on TiO2. SCR activity at low temperature correlated with lattice oxygen availability, which in turn increased for highly dispersed MnOx. The poisoning effects deriving from a hypothetical Sea Water Scrubber Desulphurization unit placed upstream of the SCR unit were investigated by ex-situ addition of KCl to the catalysts. KCl affected the acidic properties, and particularly the oxygen mobility of the catalysts, lowering, as a consequence, their SCR activity. The strong acidic character of ZSM5 enhanced the tolerance to such poisoning effect.

High precision and fast measurement of gas concentrations is important for both understanding and monitoring various phenomena, from industrial and environmental to medical and scientific applications. This article deals with the recent progress in ammonia detection using in-situ solid-state and optical methods. Due to the continuous progress in material engineering and optoelectronic technologies, these methods are among the most perceptive because of their advantages in a specific application. We present the basics of each technique, their performance limits, and the possibility of further development. The practical implementations of representative examples are described in detail. Finally, we present a performance comparison of selected practical application, accumulating data reported over the preceding decade, and conclude from this comparison.

With high porosity and being one of the most abundant clay minerals, dried kaolinite may be an excellent adsorbent to remove ammonia gas (NH3). Here, the plane wave pseudopotential method based on density functional theory (DFT) was used to explore the mechanism of ammonia gas adsorption on the dried kaolinite, the Mulliken electric charge, and the partial density of states of atoms of the NH3/kaolinite (001) system. NH3 adsorption on kaolinite can happen in three different type adsorption positions: “top”, “bridge” and “hollow”. The “hollow” position is enclosed by two "upright" hydroxyl groups perpendicular to the (001) surface of kaolinite and a "lying" hydroxyl group parallel to the surface. At this position, the adsorption is the most stable and has the highest adsorption energy. The nitrogen atom of the NH3 molecule bonds with the hydrogen atom in the "upright" hydroxyl group on the (001) surface and its hydrogen atom forms HN…O hydrogen bond with oxygen atom in the "lying" hydroxyl group, which leads to the NH3 stably adsorbed on kaolinite (001) surface. A small part of electrons transfer between NH3 molecules and kaolinite creates weakly electrostatic adsorption between them.

NH3 is a valuable chemical with a wide range of applications, but the conventional Haber–Bosch process for industrial‐scale NH3 production is highly energy‐intensive with serious greenhouse gas emission. Electrochemical reduction offers an environmentally benign and sustainable route to convert N2 to NH3 at ambient conditions, but its efficiency depends greatly on identifying earth‐abundant catalysts with high activity for the N2 reduction reaction. Here, it is reported that MnO particles act as a highly active catalyst for electrocatalytic hydrogenation of N2 to NH3 with excellent selectivity. In 0.1 m Na2SO4, this catalyst achieves a high Faradaic efficiency up to 8.02% and a NH3 yield of 1.11 × 10−10 mol s−1 cm−2 at −0.39 V versus reversible hydrogen electrode, with great electrochemical and structural stability. On the basis of density functional theory calculations, MnO (200) surface has a smaller adsorption energy toward N than that of H with the *N2 → *N2H transformation being the potential‐determining step in the nitrogen reduction reaction.

PANI/TiO2 nanocomposites spheres were synthesized using a simple and efficient one-step hydrothermal process. The morphology and structure of PANI/TiO2 nanocomposites spheres were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The PANI/TiO2 nanocomposite sphere-based sensor exhibits good selectivity, sensitivity (5.4 to 100 ppm), repeatability, long-term stability and low detection limit (0.5 ppm) to ammonia at room temperature (20 ± 5°C). It also shows a good linearity relationship in the range of 0.5–5 and 5–100 ppm. The excellent NH3 sensing performance is mainly due to the formation of the p-n heterostructure in the nanocomposites.

Reducing crude protein is a recommended technique to reduce nitrogen excretion and ammonia emissions. Greenhouse gas emissions from slurry are also affected by nutrient composition. However, there are interactions among nutrients in feeds still not clarified. The objective of this study was to evaluate the impacts of different diets on nitrogen (N) and energy balances. A total of 13 diets were evaluated in digestibility trials using 78 animals. Diets were formulated to fulfil commercial standards, although differing in ingredient composition. Nutrient intake, excretion and potential NH3 and CH4 (Biochemical methane potential) emissions from slurry were measured. Animal weight was also monitored. Correlations between emissions and nutrient balance components were done. An analysis of variance was conducted to assess differences in nutrient balance of low, medium and high emitting animals, expressing animals per kg of live weight increased. For the N balance, a two-fold range in faeces to urine N excretion ratio was found throughout the experiments, even considering the low crude protein variations (from 15 to 16%). This was related to the ammonia emissions from slurry (r = -0.60, p

The usual operation of a conductometric sensor device requires of an external energy source (i.e. an embedded heater). In the last years, the Joule effect in the sensing material, the so called self-heating effect, offered and alternative method to provide this energy: the probing current (or voltage) applied to measure the sensor signal also serves to heat up the sensor active film. Here, evidences of self-heating effects occurring on large arrays of nanostructures fabricated with low-cost methods are provided. The methodology is proven to be suitable to sense gases (humidity, NH3 and NO2) with low-powered heater-free devices.

ISSN: 2504-3900; International audience; Among all NOx reduction approaches, selective catalyst reduction (SCR) system is one the most reliable ways to control NOx emissions from diesel engine vehicles and trucks. In order to optimize the conversion rates of NOx and to prevent inducing excessive NH3 to the air, an NH3 and NOx sensor is required [1]. In this study, three different types of YSZ ink have been examined to identify the most effective electrolyte for NOx and NH3sensing. The results have shown that a home-made ink with YSZ powder shows the best sensitivity towards ammonia without polarization and the highest NO2/NO signal ratio with polarization current of 25 nA.

The high NH 3 loss to the gas stream (NH 3 slip) is one of the major issues in the ammonia based CO 2 capture technology. Meanwhile, the removal of sulphur dioxide pollutant (SO 2 ) from flue gas is a prerequisite for many CO 2 capture processes. Flue gas desulphurization (FGD) is not installed in Australian power plants and significant capital/investment costs are required to install FGD. In this study, we proposed an advanced process configuration to combine SO 2 removal and NH 3 recycling in one process development and solve these two problems together. A rate-based model for the system of NH 3 -CO 2 -SO 2 -H 2 O was established and employed to simulate the process flow sheet. The temperature, pH and N/S ratio profile, SO 2 removal and NH 3 recycling efficiency along the column were analysed. Experimental work using a bubble column was carried out to provide an initial test on the technical feasibility of the SO 2 and NH 3 absorption process. Both the modelling and experimental results suggest that the proposed process results in excellent removal and recovery of SO 2 and NH 3 .