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For a rapid transition to a carbon-neutral transport sector, hydrogen internal combustion engines could be one measure. To support the development, suitable simulation models are needed. This paper provides enhancements to an existing combustion modeling approach for lean homogeneous hydrogen–air mixtures with online reaction kinetics and combines swirl charge motion with a spark ignited combustion process. These include a real gas equation of state, a wall heat loss model that is suitable for hydrogen and a flow model. The model is implemented in Python using Cantera with a custom solver interface. The model was successfully validated through experimental measurement data from an engine test bench. Additionally, some insights into the validity of the model assumptions are given by comparing model results to three-dimensional computational fluid dynamics simulation data. • Model for a spark-ignited combustion process and swirl-based charge motion. • Solver interface for connection of thermodynamics handled by Cantera and flow model. • Successful model validation using experimental data. • Analysis of flame sphericity with 3D CFD simulation results. [ABSTRACT FROM AUTHOR]

Zn‐based catalytic batteries, recognized as eco‐friendly alternatives, are attracting significant research interest for their applications in energy storage, conversion, pollutant degradation, and ammonia synthesis. This review compiles the latest developments in Zn‐nitrogen oxides (NOx) batteries, covering various types including Zn‐nitrate, Zn‐nitric oxide, and Zn‐nitrite batteries. This study explores the electrode reactions and structural evolutions of these batteries, emphasizing the different challenges posed by cathodic reactions. Advanced design strategies for cathode materials, such as inhibiting hydrogen production, utilizing tandem sites, and enhancing reactant enrichment, are presented and evaluated. These strategies have markedly improved NOx reduction performance and have driven significant progress in Zn‐NOx battery. The future directions for research are outlined, highlighting the need for more efficient NOx reduction catalysts, optimization of Zn anodes, development of alternative metal anodes, battery structure improvements, and exploration of charging reactions. Addressing these challenges is crucial for advancing the development of eco‐friendly and high‐energy‐density Zn‐NOx batteries. [ABSTRACT FROM AUTHOR]

In the present study, the effect of biofuel and nano biofuel on the performance of a domestic boiler was investigated and compared with those emitted during the burning of diesel fuel. The biofuel was produced from waste cooking oil using Potassium hydroxide (KOH) as a catalyst. Carbon Nanotubes (CNT) with different concentrations of 0.05% /L, 0.1% /L, 0.15% /L, 0.2% /L, and 0.25% /L were added to the produced Biodiesel to form a nano biofuel that was used to power a domestic boiler for demonstration purposes. The obtained performance results were compared using the same boiler when operating with biofuel and nano biofuel, respectively. When operated with different CNT concentrations, the emitted species from the boiler were also investigated by sampling the exhaust gases in each studied case. This study revealed that the boiler's performance when operated with CNT was enhanced by decreasing the toxic emitted gasses and increasing the outlet water temperature compared to the case of the boiler with the biofuel alone. It increased the outlet water temperature and decreased NOx (ppm) emissions.

This study aims to investigate the NOx/CO reduction characteristics of harmful gases according to the loading amount of active Ag, which plays the most important role in H2-SCR, and the type of support. H2-SCR with Ag loaded on support of TiO2 was reduced to Ag+ at about 140 °C in AgO oxide, and H2-SCR with Ag loaded on support of Al2O3 was reduced to Ag clusters (Agnδ+) at about 260 °C in AgO oxide. Because it is more unstable than AgO oxide, it promoted the chemical reaction of Ag. 0.5Ag/TiO2 H2-SCR showed the highest NOx conversion rate of about 18% at 200 °C, and the window width was also widened. 2Ag/Al2O3 H2-SCR improved the low-temperature activity of the catalyst due to its large specific surface area and the loading amount of active catalyst Ag. Although the harmful gas reduction performance has decreased significantly compared to the active material Pt used in the H2-SCR, research on active materials considering the performance the improvement and economic feasibility must be continued. [ABSTRACT FROM AUTHOR]

In the present study, the effect of biofuel and nano biofuel on the performance of a domestic boiler was investigated and compared with the pollutants emitted during the burning of diesel fuel. The biofuel was produced from waste cooking oil using potassium hydroxide (KOH) as a catalyst. Carbon nanotubes (CNT) with different concentrations of 0.05%/L, 0.1%/L, 0.15%/L, 0.2%/L, and 0.25%/L were added to the produced biodiesel to form a nano biofuel that was used to power a domestic boiler for demonstration purposes. The obtained performance results were compared using the same boiler when operating with biofuel and nano biofuel, respectively. When operated with different CNT concentrations, the emitted species from the boiler were also investigated by sampling the exhaust gases in each studied case. This study revealed that the performance of the boiler when operated with CNT was enhanced by decreasing the toxic emitted gasses and increasing the outlet water temperature compared to the case of the boiler with the biofuel alone. It increased the outlet water temperature and decreased the NOx (ppm) emissions. [ABSTRACT FROM AUTHOR]

Oxime ethers are attractive compounds in medicinal scaffolds due to the biological and pharmaceutical properties, however, the crucial and widespread step of industrial oxime formation using explosive hydroxylamine (NH2OH) is insecure and troublesome. Herein, we present a convenient method of oxime ether synthesis in a one‐pot tandem electrochemical system using magnesium based metal‐organic framework‐derived magnesium oxide anchoring in self‐supporting carbon nanofiber membrane catalyst (MgO‐SCM), the in situ produced NH2OH from nitrogen oxides electrocatalytic reduction coupled with aldehyde to produce 4‐cyanobenzaldoxime with a selectivity of 93 % and Faraday efficiency up to 65.1 %, which further reacted with benzyl bromide to directly give oxime ether precipitate with a purity of 97 % by convenient filtering separation. The high efficiency was attributed to the ultrafine MgO nanoparticles in MgO‐SCM, effectively inhibiting hydrogen evolution reaction and accelerating the production of NH2OH, which rapidly attacked carbonyl of aldehydes to form oximes, but hardly crossed the hydrogenation barrier of forming amines, thus leading to a high yield of oxime ether when coupling benzyl bromide nucleophilic reaction. This work highlights the importance of kinetic control in complex electrosynthetic organonitrogen system and demonstrates a green and safe alternative method for synthesis of organic nitrogen drug molecules. [ABSTRACT FROM AUTHOR]

The current research investigates the impact of a split fueling strategy combined with several flow rates of exhaust gas recirculation (EGR) on the combustion and emission characteristics of a diesel engine running on B20 waste cooking oil (WCO) biodiesel. A four‐stroke single‐cylinder common rail direct injection engine was employed for experiments. It operates with a B20 blend of WCO biodiesel at 600 bar pressure for varying pilot fueling conditions of 10%, 20%, and 30%. The B20 blend with 30% pilot fuel injection (B20P30) showed excellent performance and emission characteristics compared with B20 blend with 10% pilot fuel injection (B20P10) and B20 with 20% pilot fuel injection (B20P20). However, B20P30 had greater levels of nitrogen oxide (NOx) emissions than those by diesel. EGR discharge levels in 5% increments, ranging from 0% to 15% were introduced to address this issue. The experimental findings revealed that both cylinder peak pressure and heat release rate showed a reduction when the EGR flow rate was enhanced. The recirculation of exhaust gas into the combustion chamber led to a slight increase in the emission levels of hydrocarbon (HC), carbon monoxide (CO), and smoke, as well as a decrease in carbon dioxide (CO2). Nevertheless, the introduction of EGR significantly decreased NOx emissions by 22.94%, 35.05%, and 47.96% for EGR flow rates of 5%, 10%, and 15%, respectively, when compared with the engine operating without EGR. Overall, the two‐stage fueling strategy, B20P30 blended with 10% EGR corroborated to be beneficial in reducing NOx emissions with minimal performance penalties. Although there was a slight uptick in certain emissions, the overall trade‐off between emission reduction and performance was favorable. The culmination of this study is targeting the objectives of sustainable development goal 7 (clean energy) and goal 13 (climate action) to be achieved by 2030. [ABSTRACT FROM AUTHOR]

Ammonia have been attractive as one of the alternative fuels for reducing greenhouse gas (GHG) emissions. However, ammonia combustion has lower combustion performance than common hydrocarbon fuels. Furthermore, it may emit nitrous oxide (N 2 O), which is one of the GHGs. This paper presents the experimental investigations of plasma-assisted ammonia combustion (PAAC) using a rod-electrode-type microwave plasma source (MPS) at atmospheric pressure. The equivalence ratios of premixed ammonia/dry air (NH 3 /Air) gas are set below the stoichiometric combustion of NH 3 to reduce toxic NH 3 in the combustion gas. Under the condition of the equivalence ratios, the experiments are focused on reducing the unburned NH 3 and produced N 2 O concentrations in the combustion gas. In the experiments, the unburned NH 3 , nitrogen oxide (NO x) (the sum of nitric oxide (NO) and nitrogen dioxide (NO 2)), and N 2 O concentrations in the combustion gas are investigated in terms of the flow velocity of premixed NH 3 /Air gas inside the rod-electrode-type MPS and the transmission power to the rod-electrode-type MPS. In conclusion, the rod-electrode-type MPS is identified to be useful for PAAC. The NH 3 and N 2 O concentrations in the combustion gas reach approximately 25 and 4 parts per million (ppm), respectively, under the conditions of the equivalence ratio of 1.0, flow velocity of approximately 0.167 m/s, and transmission power of about 84 W. At that time, the NO x concentration is approximately 4300 ppm, and the power transmission efficiency is approximately 68 %. • Plasma-assisted ammonia combustion (PAAC) was conducted using microwave discharge. • The microwave discharge was generated using a rod-electrode-type microwave plasma source (MPS). • The experiments were conducted without a swirler and below the stoichiometric combustion. • The minimum concentrations of NH 3 and N 2 O in the combustion gas reached 25 and 4 ppm. • The rod-electrode-type MPS was identified to be useful for PAAC. [ABSTRACT FROM AUTHOR]

The paper studies the thermal schemes and construction characteristics of gas turbine units. The pros and cons of the considered turbines are compared with steam turbine units. At the same time, the amount of nitrogen gas coming out of the gas turbine and a steam turbine of the same power is calculated and a comparative analysis is given. It is found that the amount of nitrogen gas coming out of the gas turbine is 4 times less than that of the steam turbine. [ABSTRACT FROM AUTHOR]

A series of novel Mn6Zr1-xCox denitrification catalysts were prepared by the co-precipitation method. The effect of co-modification of MnOx catalyst by zirconium and cobalt on the performance of NH3-SCR was studied by doping transition metal cobalt into the Mn6Zr1 catalyst. The ternary oxide catalyst Mn6Zr0.3Co0.7 can reach about 90% of NOx conversion in a reaction temperature range of 100-275°C, and the best NOx conversion can reach up to 99%. In addition, the sulfur resistance and water resistance of the Mn6Zr0.3Co0.7 catalyst were also tested. When the concentration of SO2 is 200ppm, the NOx conversion of catalyst Mn6Zr0.3Co0.7 is still above 90%. 5 Vol% H2O has little effect on catalyst NOx conversion. The results showed that the Mn6Zr0.3Co0.7 catalyst has excellent resistance to sulfur and water. Meanwhile, the catalyst was systematically characterized. The results showed that the addition of zirconium and cobalt changes the surface morphology of the catalyst. The specific surface area, pore size, and volume of the catalyst were increased, and the reduction temperature of the catalyst was decreased. In conclusion, the doping of zirconium and cobalt successfully improves the NH3-SCR activity of the catalyst. [ABSTRACT FROM AUTHOR]

The growth of hydrogen as an alternative clean fuel for fulfilling thermal energy needs of multiple economic sectors globally requires access to reliable, safe, energy efficient, emission free combustion technology. The work described in this short communication shows the applicability of a novel heterogeneous combustion design in utilizing a wide range of hydrogen blended methane concentrations to cleanly and safely generate thermal energy. The utilization of a simple first principles design approach along with engineered materials yielded a fuel-flexible hybrid infrared-convection burner design capable of lowering NOx emissions by more than 95% while simultaneously improving the heat transfer efficiency by 15% with a wide range of hydrogen concentrations. The safety and performance of the combustion design was demonstrated in an burner at capacities of up to 12,000 Btu/h in producing temperatures of 900 °C. The atmospheric burner concept was integrated in a cooktop configuration with combined thermal power rating of 30,000 Btu/h and operated with hydrogen blended natural gas. • Safe combustion of hydrogen-blended methane compositions was achieved. • Infrared thermal output lowered the NOx emissions by 90% compared with a conventional blue flame burner. • Safe combustion with hydrogen blends is enabled by the tortuous path of the heterogeneous media. • Heat energy utilization efficiency was enhanced by up to 15% due to radiative heat transfer. [ABSTRACT FROM AUTHOR]

In this work, a new composite photocatalyst was synthesized by flower-like Bi2O3 and two-dimensional multilayer V2C using a facile hydrothermal method. Compared with the pristine sample, the specific surface area of Bi2O3/V2C MXene composite is significantly increased, which is favourable to improve the photocatalytic efficiency. The analysis of the UV-vis absorption spectrum and band gap energy shows that the construction of heterojunction broadens the light response range, improves the light absorption capacity, and obtains a narrower band gap than any of the single component, which is beneficial to the utilization of light. PL, TPC and EIS analysis revealed that Bi2O3/V2C MXene composite had stronger carrier mobility, which further confirmed that the photocatalytic oxidation performance of the system was the dominant reason in the photocatalytic NO pollutant removal process. This study provides a new idea for better understanding the two-dimensional MXene material-based photocatalyst and improving the NO removal efficiency. [ABSTRACT FROM AUTHOR]

GLOBAL CLIMATE The dominant greenhouse gases released into Earth's atmosphere including carbon dioxide, methane, and nitrous oxide reached record highs in 2022. The annual global average carbon dioxide concentration at [...]

Yessy Novianti,1 Wahyu Hidayat,2 Desi Elvhira Rosa1 1Oral Medicine Residency Program, Faculty of Dentistry, Universitas Padjadjaran, Bandung, Indonesia; 2Department of Oral Medicine, Faculty of Dentistry, Universitas Padjadjaran, Bandung, IndonesiaCorrespondence: Yessy Novianti, Faculty of Dentistry, Universitas Padjadjaran, Sekeloa Selatan Street No. 1, Bandung, 40132, Indonesia, Tel +6281368429045, Email yessy21001@mail.unpad.ac.idIntroduction: Psoriasis is a complex autoimmune disease associated with chronic systemic keratinization and inflammation, which can affect the skin, joints, and oral cavity. Xerostomia is a subjective feeling of oral dryness that impairs patient comfort and lowers the quality of life. The aim of this case report is to describe the clinical mechanism of xerostomia in a psoriasis patient with multiple systemic diseases.Case Report: A 51-year-old inpatient man with psoriasis vulgaris was referred to the Oral Medicine Department with complaints of difficulty swallowing due to a sore throat and dry tongue since last week. The patient had psoriasis vulgaris 15 years ago, chronic adrenal insufficiency, psoriatic arthritis, acute circulatory collapse, anemia of inflammation, acute kidney injury, dehydration, gastritis, urinary tract infections, and malnutrition. A complete anamnesis and oral examination were done. The patient was diagnosed with severe xerostomia, a fissured tongue, exfoliative cheilitis, angular cheilitis, and gingivitis by the Oral Medicine Department.Case Management: The patient was treated with petroleum jelly, chlorine dioxide mouthwash, miconazole cream, and benzydamine HCl lozenges.Conclusion: Based on case reports and reviews, multiple systemic diseases may not only increase the risk of xerostomia but also aggravate its severity.Keywords: acute kidney injury, inflammation, nitrogen oxide, psoriasis arthritis, SXI-ID

Objectives The study was aimed to systematically understand the nitrogen budget from 2015 to 2019, and to determine the annual nitrogen balance in South Korea. Methods The nitrogen budget was calculated by classifying into agricultural and livestock, city, and forest areas. The nitrogen input was estimated from deposition, biological fixation, agricultural water, inorganic chemical fertilizer, compost, feedstuff, produced crops, imported grocery, and fuel consumption. The nitrogen output was estimated by considering denitrification, volatilization, ground water runoff, land and crop absorption, sewage disposal, drainage, forest uptake, and nitrogen oxide (NOx) emissions. Results and Discussion The annual nitrogen budget from 2015 to 2019 showed the input as 6,107,449 ton/yr, 6,144,666 ton/yr, 6,245,240 ton/yr, 6,281,552 ton/yr, 5,993,347 ton/yr and the output as 1,346,587 ton/yr, 1,369,119 ton/yr, 1,365,327 ton/yr, 1,378,940 ton/yr, 1,365,994 ton/yr, respectively. The NOx, highly contributing to change in the nitrogen budget, was caused by human activities such as vehicles, business places, and power plants. More than 32% of the total nitrogen budget was caused by NOx in every year. Conclusion The nitrogen budget continued to increase in the 2010s because of the increase in food and fuel consumption by urbanization. However, the nitrogen budget declined in 2019 due to the effort such as emission regulations and the use of alternatives as the awareness of environmental pollution gradually increased. Therefore, the appropriate institution should be established and actively implemented to reduce the nitrogen effectively.

Introduction. Copper ions (Cu2+) are structural elements of proteins such as cytochrome с oxidase (Complex IV), an enzyme that catalyzes the final step of electron transfer to oxygen during oxidative phosphorylation in the mitochondria. With Cu2+ homeostasis being of utmost importance, its disturbances in the central nervous system are involved in the mechanisms of many neurodegenerative and other brain disorders. This study aimed to assess the effects of non-toxic copper ion levels on death of cerebellar granule neurons associated with lipopolysaccharide (LPS; in vitro inflammation model) or azide sodium (NaN3; cytochrome с oxidase inhibitor). Materials and methods. LPS (10 μg/mL) or NaN3 (250 μM) was added on day 7 to 8 to the culture medium with rat cerebellar cells for 24 hours in vitro. Nitrite concentrations were measured in the culture medium by Griess assay; absorbance was recorded with a spectrophotometer at 540 nm, and morphologically intact cells were counted as survived neurons. Results. Added to the culture medium, LPS or NaN3 reduced neuron survival to 15 ± 2% or 20 ± 3% vs. control, respectively. Cu2+ (0.5 to 5.0 μM) increased neuron survival in a dose-dependent manner to 78 ± 4% with toxic levels of LPS and to 86 ± 6% with NaN3 with 5 μM Cu2+. The concentration of nitrites in the control culture medium was 2.0 ± 0.2 μM. Added to the cell cultures, LPS increased the concentration of nitrites to 8.5 ± 0.5 μM. Cu2+ 5 μM did not show any significant effects on nitrite accumulation in the culture medium. Conclusions. We showed that copper ions can exert protective effects on neurons against LPS-induced or NaN3-induced toxicity. This protection is likely to be associated rather with Cu2+ interaction with Complex IV of the electron transfer chain in the mitochondria than with inhibition of NO production. Effects of Cu2+ on apoptosis pathway proteins also cannot be ruled out.

Based on the results of a comprehensive experiment conducted in September 2020, the spatial distribution of the following trace gases over the seas of the Russian Arctic are analyzed: carbon monoxide (CO), ozone (O3), nitrogen oxide and dioxide (NO and NO2), and sulfur dioxide (SO2). It is shown that the gas concentrations in the surface air layer over the seas (at an altitude of 200 m) vary in the range 18–36 ppb for O3, 60–130 ppb for CO, 0.005–0.12 ppb for NO, 0.10–1.00 ppb for NO2, and 0.06–0.80 ppb for SO2. The distribution of the gases over the water area is heterogeneous over most seas, which most likely reflects differences in their uptake by the ocean and peculiarities of transport from the continent. [ABSTRACT FROM AUTHOR]

Pt/ZrP2O7 catalysts exhibiting high activity for catalytic NOx reduction by H2 in the presence of excess O2 were developed in this study. At a low temperature of 125 °C and a high space velocity of approximately 5 × 104 h–1, 0.4 wt % Pt/ZrP2O7 facilitated a higher NO conversion to N2 (51%) than 0.4 wt % Pt/ZrO2 (<5%) for a reaction mixture of 200 ppm NO, 5000 ppm H2, 10% O2, and He balance. However, N2O and NO2 production increased at temperatures lower than 100 °C and higher than 200 °C, thereby decreasing the N2 yield. High-resolution electron microscopy and X-ray photoelectron spectroscopy analyses of 0.4 wt % Pt/ZrP2O7 revealed the coexistence of large metallic Pt crystallites with sizes of ∼20 nm and highly dispersed Pt oxide nanoclusters. When Pt loading was decreased to 0.05 wt %, the large metallic Pt crystallites disappeared, and only the Pt oxide nanoclusters remained on ZrP2O7. Owing to this structural change, N2O/NO2 formation was significantly suppressed, enabling highly selective NO reduction to N2. Moreover, catalyst preparation by equilibrium adsorption instead of wet impregnation further improved the reaction, achieving >90% selective NO conversion to N2, which was nearly free of undesired byproducts (NH3, N2O, and NO2) at 175 °C. The Pt oxide nanocluster supported on ZrP2O7 was more tolerant to the presence of 10% water vapor in the exhaust gas than the metallic Pt particles. Therefore, the developed catalyst is suitable for applications in practical exhaust gas purification for H2-fueled internal combustion engines. [ABSTRACT FROM AUTHOR]

Traditional TiO2 semiconductor is a promising photocatalyst. However, the extended application of this material for nitrogen oxide (NO) removal under sunlight conditions is becoming an emerging topic in materials science. Combining and modifying TiO2 with carbon materials such as carbon nanotube (CNT) towards applying a promising photocatalyst for gas pollution treatment have received much more significant attention. Herein, we combine and optimize CNT and commercial TiO2 by a ball-milling method towards a better photocatalyst in solar light driven. The analysis results indicated the existence of spherical TiO2 particles with an average diameter of 80–100 nm and CNT with a length and diameter of several nanometers and approximately 8–10 nm in the composites. The photocatalytic NO evaluation under a natural environment simulation model indicates that 0.7%wt CNT in CNT/TiO2 composite (0.7CT sample) achieves the most excellent photocatalysis. The CNT/TiO2 composites also express high stability. However, the CNT/TiO2 composite still has a limitation with a high NO to NO2 conversion yield. [ABSTRACT FROM AUTHOR]

The study of the interaction of NO molecules with two P‐ and N‐doped volleyballenes is delivered. It is found that [Sc20C48N12][0,−1] and [Sc20C48P12]−1 structures are able to split N‐O bonds without an energy barrier. The N‐doped structures can break up to six NO molecules, and therefore, their IR/Raman spectra are missing of N‐O vibration peaks. Moreover, we determine that N‐O bond can be considered as broken starting from 1.39 Å distance. [ABSTRACT FROM AUTHOR]

The effect of hydrogen co-firing on the performance and operating conditions of gas turbines (GTs) and gas turbine combined cycles (GTCCs) was investigated. Two operating scenarios were applied, and off-design analyses were conducted for three GTs with different turbine inlet temperatures (TITs). In the first scenario, the TIT was kept constant. As the hydrogen co-firing ratio increases, the pressure ratio of GT increased, and the power outputs of both GT and GTCC increased. With 100 % hydrogen in the 1650 °C GT, power output and efficiency improved by 5.36 % and 1.55 %p for GT, and 2.90 % and 0.72 %p for GTCC. In the second scenario, the power output was kept constant. The operating point moves toward lower pressure ratio and TIT regimes, and the efficiency of both GT and GTCC increased. With 100 % hydrogen in the 1650 °C GT, TIT decreased by 50.3K, and efficiency increased by 1.42 %p for GT, and 24.9K and 0.42 %p for GTCC. In both scenarios, the higher the TIT, the impact of hydrogen co-firing was more pronounced. It is expected that the second scenario might reduce NOx emissions while still increasing system efficiency in comparison to the NG fired case by operating the GT at a lower TIT and equivalence ratio.

Pyridine oximes produced from aldehyde or ketone with hydroxylamine (NH2OH) have been widely applied in pharmaceutics, enzymatic and sterilization. However, the important raw material NH2OH exhibits corrosive and unstable properties, leading to substantial energy consumption during storage and transportation. Herein, this work presents a novel method for directly synthesizing highly valuable pyridine oximes using in situ generated NH2OH from electrocatalytic NO reduction with well‐design nanofiber membranes (Al‐NFM) derived from NH2‐MIL‐53(Al). Particularly, 2‐pyridinealdoxime, the precursor of antidote pralidoxime (2‐PAM) for nerve agents suffering from scarcity and high cost, was achieved with a Faraday efficiency up to 49.8 % and a yield of 92.1 %, attributing to the high selectivity of NH2OH production on Al‐NFM, further easily reacted with iodomethane to produce 2‐PAM. This study proposes a creative approach, having wide universality for synthesizing pyridine and other oximes with a range of functional groups, which not only facilitates the conversion of exhaust gas (NO) and waste water (NO2−) into valuable chemicals especially NH2OH production and in situ utilization through electrochemistry, but also holds significant potential for synthesis of neuro detoxifying drugs to humanity security. [ABSTRACT FROM AUTHOR]

Ammonia is an ideal renewable, carbon-free fuel and hydrogen carrier, which produces nitrogen and water after complete combustion in the presence of oxygen. However, ammonia has low reactivity, slow flame-propagation speed, and carries risks of high nitrogen oxide (NOx) emissions. Co-firing ammonia with an industrial by-product gas (with CH4 and CO being the main combustible materials) is a cost-effective and convenient method of improving the combustion characteristics of ammonia, but attention still needs to be paid to the NOx generation. Currently, the research on NOx formation during co-firing of ammonia with other fuel gases is still insufficient. In this study, a high-temperature furnace reaction system was used to investigate the NOx formation and inhibition mechanisms during the combustion of NH3/CH4 and NH3/CO mixtures. By varying the ammonia blending ratio, excess air coefficient (α), temperature, residence time, and fuel concentration, the key factors influencing NOx generation and inhibition were further analyzed. The results showed that when α was no less than 1, the production of NOx initially increased and then decreased with an increasing proportion of ammonia in the fuel gas. Within the temperature range of 900 °C to 1500 °C, the amount of NOx generated during the combustion of the mixed gas gradually decreased with the increase in temperature. Under the conditions of NH3/CH4 and NH3/CO, the emissions of NOx were higher than those during pure ammonia combustion. [ABSTRACT FROM AUTHOR]

As the only controllable means of a micro gas turbine (MGT) combustor during unit operation, pilot fuel ratio (PFR) is the key to achieving stable combustion and low pollutant emission. This paper discusses the influence of PFR on the inner flow field structure and pollutant emissions. The steady-state three-dimensional RANS method with a 40-step reduced methane-air kinetics mechanism is used to study the reaction flow field and species field with PFR of 9.0%, 12.7%, 15.2% and 17.6%. Results show that, with the decrease in PFR, the axial velocity and temperature near the central axis of the combustion chamber show a tendency to decrease. A similar separation phenomenon occurred in the core pyrolysis reaction zone (measured by HCO) and oxidation zone (measured by OH), which is more conducive to promoting the oxidation of CO. The quantitative effect of the pilot flame on nitrogen oxides (NOx) was separated by using inert gas instead of nitrogen in combustion air. It was found that the NOx produced by the pilot flame under the operation condition with a PFR of 9.0% was 3.2×10−6, accounting for 17.4% of the total NOx emission, which was twice that of PFR. [ABSTRACT FROM AUTHOR]

Air pollution in Chinese megacities by particulate matter and ozone is a major health problem originating partly from emissions of nitrogen oxides. Therefore, there is a need for advanced methods to remove nitrogen oxides, such as photocalalysis using polymeric carbon nitride, yet this process is limited by low visible-light absorption and specific surface area, rapid recombination of carriers, and uncontrolled conversion pathways. Here we review catalysts made of polymeric carbon nitride for the removal of nitrogen oxides with focus on extending light absorption, enlarging surface area, inhibiting photogenerated carrier recombination, regulating the reaction process, outdoor applications, and reduction of nitrogen oxides to dinitrogen. [ABSTRACT FROM AUTHOR]

Nitrogen oxides (NO x) and ammonia (NH 3) are coexisting in fuel cell vehicles' working condition such as urban industrial areas, which are harmful impurities to proton exchange membrane fuel cell (PEMFC). In this work, an experimental investigation between NH 3 alone, NO x alone, and 1:1 mixed NH 3 /NO x are conducted at different concentrations. Voltage time curve and electrochemical impedance spectroscopy (EIS) analyses show that mixed gases cause slighter poison effect than single gas. Mixed 20 ppm NO x and 20 ppm NH 3 caused a −14 mV/h voltage decay rate, while that of 20 ppm NO x alone and 20 ppm NH 3 alone were −5 mV/h and −18 mV/h. Meanwhile, by comparing the poison and recovery processes between different impurity gases at different concentrations, mechanism of synergistic poisoning is proposed. A fast voltage decay rate caused by NO x and an irreversible performance loss caused by NH 3 are observed in sequence at higher concentration, which due to the different adsorption energy of NO x and NH 3 and the different reactions occurring in the membrane electrode assemblies (MEAs). • Mitigated performance loss caused by mixed NH 3 and NO x impurities is observed. • NO x dominates the synergistic poison process in preliminary stage at 20 ppm. • Comparing to pure NH 3 or NO x , voltage decay rate is reduced by 40% in mixed NH 3 and NO x at 5 ppm. [ABSTRACT FROM AUTHOR]