Ammonia Research Articles

Engineering MgHPO4·3H2O/Mg(OH)2 composite for boosting NH3 adsorption properties

The emission of ammonia gas (NH3) in agricultural composting not only leads to a decrease in fertilizer efficiency, but also causes environmental pollution. Here, an alkaline, insoluble composites was prepared and its adsorption performance for NH3 was explored. The results indicate that the material synthesized using a one-pot method with magnesium hydroxide (Mg(OH)2) and phosphoric acid (H3PO4) consists of a mixture of MgHPO4·3 H2O and Mg(OH)2 (M1). TEM images reveal the adhesion of the two materials together, with Raman spectroscopy indicating that MgHPO4·3 H2O is located on the outer surface of Mg(OH)2. The microenvironment formed by the adhesive construction of MgHPO4·3 H2O and Mg(OH)2 mixture not only provides sufficient magnesium salts and phosphate for the growth of struvite but also creates alkaline conditions conducive to struvite formation. The kinetic results show that the NH3 adsorption of M1 follows pseudo second-order adsorption kinetics and belongs to surface chemical reaction control. Compared with a simple mixture of MgHPO4·3 H2O and Mg(OH)2, M1 has a 4.5 fold increase in NH3 adsorption rate and a 3.15 fold increase in equilibrium adsorption capacity. Preliminary on-site tests demonstrated the potential application of the M1 adsorbent for NH3 adsorption in composting.

Strategic control of combustion-induced ammonia emissions: A key initiative for substantial PM2.5 reduction in Tianjin, North China Plain

Information on the temporal and spatial variations in the sources of ammonium salts (NH4+), a crucial alkaline component in PM2.5, is limited. Here, we simultaneously collected PM2.5 and gaseous ammonia (NH3) samples in both summer and winter from two sites in Tianjin: an urban site (Tianjin University, TJU) and a suburban site (Binhai New-region, BH). NH3 concentrations, the contents of major water-soluble inorganic ions in PM2.5, and the compositions of ammonium‑nitrogen isotopes (δ15N-NH4+) were measured. As a result, (NH4)2SO4 and NH4NO3 were the predominant forms of NH4+ in PM2.5 during summer and winter, respectively. However, the NH4NO3 concentrations were notably greater at TJU (6.2 ± 7.3 μg m−3) than at BH (3.8 ± 4.7 μg m−3) in summer, with no regional differences observed in winter. Both sites displayed almost half the contribution of c-NH3 (combustion-related NH3) to NH4+, differing from the finding of previous isotope-based studies. This discrepancy could be attributed to the combined effects of NHx isotope fractionation and seasonal δ15N value variations in NH3 sources. The contribution fractions of v-NH3 (volatile NH3) and c-NH3 exhibited similar patterns at both sites seasonally, probably caused by coal combustion for heating in winter and temperature fluctuations. However, the contribution fraction of c-NH3 was lower at BH than at TJU in summer but greater in winter than at TJU. In summer, NH4NO3 was unstable and limited its delivery to TJU from BH, and the high contribution of c-NH3 to NH4+ at TJU could be attributed to local vehicle emissions. In winter, the stable particulate NH4NO3 that formed from the c-NH3 in the upwind area could be transported to the downwind area, increasing the NH4+ concentration at BH. Our study provides valuable insights for devising emission mitigation strategies to alleviate the increasing burden of NH3 in the local atmosphere.

Density functional theory based analyses of beryllium oxide fullerene assisted adsorptions of ammonia, phosphine, and arsine toxic gases towards sensing and removal prospective applications

The gas sensing and removal prospective was investigated in the current work to analyze a beryllium oxide (BeO) fullerene for the adsorptions of ammonia (NH3), phosphine (PH3), and arsine (AsH3) toxic gases along with applications density functional theory (DFT) calculations. The optimization of models yielded the formations of interacting BeO-NH3, BeO-PH3, and BeO-AsH3 complexes with the adsorption strengths of −25.96, −8.75, −29.09 kcal/mol, respectively. The models were analyzed further based on the nature of interactions, in which the beryllium atom showed a significant role of the existence of interactions through the formation of direct Be…N, Be…P, and Be…As interactions. Analyses of structural features indicated a priority of formation for the BeO-AsH3 complex in comparison with the BeO-NH3 and BeO-PH3 complexes. The evaluated electronic features based on the frontier molecular orbitals and transferred charges also indicated a differential diagnosis of models along with a meaningful sensing activity of BeO for the gas substances. As a consequence, the successful formation of BeO-NH3, BeO-PH3, and BeO-AsH3 complexes and their featured properties were found useful for approaching the sensing and removal prospective applications.

Ni2Mo3N: crystal structure, thermal properties, and catalytic activity for ammonia decomposition

Abstract Ni2Mo3N was synthesized by ammonolysis of NiMoO4, prepared by a sol-gel-based modified Pechini route. X-ray powder diffraction measurements confirmed that Ni2Mo3N crystallizes in a filled β-Mn type (cubic space group P4132) with a lattice parameter of a = 6.6338 Å. Group theoretical methods were applied to elucidate the relation between the crystal structure of Ni2Mo3N and that of the rock salt type. The high-temperature behavior was investigated in-situ by X-ray diffraction measurements in flowing ammonia gas at temperatures up to 875 °C. Ni2Mo3N exhibits significant catalytical activity for ammonia decomposition, which is critically discussed in comparison to literature.

The effect of carvacrol, thymol, eugenol and α-terpineol in combination with vacuum packaging on quality indicators of anchovy fillets

Food safety issues associated with the increased use of synthetic and chemicals preservatives agents are receiving increasing attention. The utilisation of natural resources may provide a potential and advisable alternative to chemical preservatives in the seafood industry. This research study focused on the impacts of pure bioactive compounds (carvacrol, thymol, eugenol, and α-terpineol) on the sensory and microbiological (total viable count, TVC) and chemical qualities (total volatile basic nitrogen (TVB-N) value, thiobarbituric acid (TBA), free fatty acid (FFA), and peroxide value (PV)) of vacuumed packaged anchovy (Engraulis encrasicolus) fillets during the refrigerated storage period. This study also evaluated the potential effect of bioactive compounds on biogenic amines (BAs) and ammonia (AMN) production in fish samples. Sensory investigations revealed that the control had an 8-day shelf life, that of the carvacrol and α-terpineol treatment was 15 days, and that of the thymol and eugenol treatment was 19 days. The application of bioactive compound on fish had a positive impact on the preservation of its oxidative stability through the reduction of TBA, FFA, and PV values as well as enhancement of the microbiological quality in comparision to the control. The use of pure bioactive compounds resulted in the reduction of the accumulation of BAs and AMN in anchovy fillets during 22 days of storage. The results exhibited that the pure bioactive compounds mainly eugenol and thymol, can increase the shelf life of anchovy. Therefore, they can be used by seafood industries as preservative agents due to their good antimicrobial and antioxidant activities.

Nitrogen-doped carbon nano-onions/polypyrrole nanocomposite based low-cost flexible sensor for room temperature ammonia detection

One of the frontier research areas in the field of gas sensing is high-performance room temperature-based novel sensing materials, and new family of low-cost and eco-friendly carbon nanomaterials with a unique structure has attracted significant attention. In this work, we propose a novel low-cost flexible room temperature ammonia gas sensor based on nitrogen-doped carbon nano-onions/polypyrrole (NCNO-PPy) composite material mounted low-cost membrane substrate was synthesized by combining hydrothermal and in-situ chemical polymerization methods. The proposed flexible sensor revealed high sensing performance when employed as the sensing material for ammonia detection at room temperature. The NCNO-PPy ammonia sensor exhibited 17.32% response for 100 ppm ammonia concentration with a low response time of 26 s. The NCNO-PPy based flexible sensor displays high selectivity, good repeatability, and long-term durability with 1 ppm as the lower detection limit. The proposed flexible sensor also demonstrated remarkable mechanical robustness under extreme bending conditions, i.e., up to 90° bending angle and 500 bending cycles. This enhanced sensing performance can be related to the potential bonding and synergistic interaction between nitrogen-doped CNOs and PPy, the formation of defects from nitrogen doping, and the presence of high reactive sites on the surface of NCNO-PPy composites. Additionally, the computational study was performed on optimized NCNO-PPy nanocomposite for both with and without NH3 interaction. A deeper understanding of the sensing phenomena was proposed by the computation of several electronic characteristics, such as band gap, electron affinity, and ionization potential, for the optimized composite.

Ultrasensitive and selective Cr-doped ZnO thin films synthesized via spray pyrolysis technique for detection of ammonia gas

Ultrasensitive and selective Cr-doped ZnO thin films synthesized via spray pyrolysis technique for detection of ammonia gas

Meta-Analysis of the Effect of Inorganic Micro/Nanomaterial Additives on Polyaniline Based NH<sub>3</sub> Gas Sensor Performance

Nowadays conducting polymer based nanocomposites become promising materials for various field of applications like energy harvesting, electronics, and gas sensing devices. This work focuses on the meta-analysis of the effect of different inorganic micro/nano-material additives on polyaniline (PAni) based nanocomposite for ammonia (NH3) gas sensor application at room temperature. The considered NH3 sensors performance parameters are sensitivity, limit of detection (LOD), response time, and recovery time. These parameters show a significant change when inorganic materials like graphene, metal oxides and ternary hybrid materials are mixed with PAni as compared to pure PAni due to the synergetic effect of the micro/nano hybrid combination. The changes in the sensitivity, LOD, response time, and recovery time are elaborated by considering different inorganic micro/nano-material additives in PAni in the framework of pure PAni as a reference point. It is found from analysis that a micro/nano additive in the PAni matrix serve as catalyst and create more active sites in the system, which improves the sensitivity in the range of 23-130 times and LOD is highly reduced by 10-1 to 10-3 order when compared with the sensitivity and LOD of pure PAni. Hence these additives in PAni-based nanocomposite are very crucial and make nanocomposite cost-effective compared to conventional NH3 gas sensors while working at room temperature.

TiO2 decorated MXene nanosheets for high-performance ammonia gas sensing at room-temperature

A room-temperature sensor with superior performance to detect traces of toxic gas molecules is highly desirable. MXenes, due to their unique planar structure, higher electrical conductivity and abundant functional groups on the surface, have emerged as leading low dimensional gas sensing materials. But, the gas sensors based on Ti3C2Tx MXene possess higher detection limit and poor long-term stability, thereby limiting their applications. However, TiO2 modified Ti3C2Tx as a gas sensing platform has displayed improved ammonia sensing performance. Here, we report a facile method to prepare Ti3C2Tx/TiO2 composite via calcination of Ti3C2Tx. The experimental results indicate that the oxidation temperature plays a key role in the morphology evolution and gas-sensing performance of Ti3C2/TiO2 composites. Compared to the as obtained Ti3C2Tx, the Ti3C2Tx/TiO2 composite obtained at 200 °C displays improved response to NH3 gas due to the formation of a heterointerface between Ti3C2Tx and TiO2. Room-temperature, selective ammonia detection down to 5 ppb has been obtained. Moreover, the device displayed a stable sensing response to 10 ppb of ammonia over the RH range of 26%–90%. It also displayed higher selectivity to NH3 over other analytes including dimethyl formamide, ethanol, isopropyl alcohol, methanol, acetone, chloroform, xylene and N-methyl pyrolidone. The results suggest that by appropriate engineering of the Ti3C2Tx/TiO2 composites, ammonia sensor with improved sensing performance can be designed.

Investigation on toxicity of ammonia releasing from storage tank onboard through CFD simulations

ABSTRACT This study investigates potential risks associated with ammonia releases from a case ship to be constructed in a Korean Shipyard and operated in Korean coastal areas. The focus is on understanding how ammonia disperses from the onboard storage tank’s Vent Master and the associated toxic zones. Numerical simulations using CFD tools were employed to model ammonia gas dispersion scenarios. The study revealed that if the safety valve opens, the high internal pressure of the ammonia tank could release a significant amount of ammonia through the vent mast. Thus, determining the position and height of the vent mast is crucial for safety design. Simulations showed that even if ammonia is released at sea through the vent mast, it poses minimal risk to nearby residential areas. The vent mast, positioned at least 4 m above the ship’s deck, ensured rapid gas dispersion, reducing the chance of human exposure. The findings aim to enhance the safety design and operation of ships, providing valuable reference material for policymakers, regulators, engine manufacturers, and ammonia suppliers, ultimately contributing to the establishment of safe ship design and construction practices in the future.

Time-resolved investigations of a glow mode impulse dielectric barrier discharge in pure ammonia gas by means of E-FISH diagnostic

Time-resolved electric field strength measurements have been performed, using an electric-field induced second harmonic (E-FISH) diagnostic, in a nanosecond glow discharge of an impulse dielectric barrier discharge, in an ammonia gas environment. A temporal resolution of 2 ns and a spatial resolution estimated at 70 µm (given by laser waist) have been achieved. The comparative study of E-FISH measurements with and without a plasma discharge, operated at 4 kHz, reveal the presence of a persistent counter electric field, which is assumed to be caused by charge accumulation in between the AlN dielectrics used. Furthermore, by studying the influence of the applied voltage, the pressure, and the inter-dielectric distance, measurements seem to indicate the presence of charges remaining also in the post-discharge volume from the previous discharge to the next one.

Enhancing the efficiency of gas sensing on perovskite BaTiO3 nanoparticles using dynamic shock wave flow environment

The effect of nonlinear dynamic shock waves on perovskite BaTiO3 nanoparticles (NPs) is investigated using a table top pressure-driven shock tube (Reddy Tube) for ammonia gas sensing applications with the Mach number of 2.2. In general, shock waves are a nonlinear high-pressure phenomenon characterized by high dynamic pressure and temperature. Raman and powder X-ray diffraction (XRD) methods were utilized to evaluate the molecular and structural characteristics of the BaTiO3 (BTO) NPs under the influence of dynamic shock waves. The surface absorption was assessed using UV- diffuse reflectance spectroscopy (UV-DRS). XRD data shows that BaTiO3 NPs crystallized in tetragonal crystal structure with P4mm space group and stable throughout the shocks, without undergoing any phase change. The average particle size of the control BaTiO3 was 31 nm, while those of shocked BaTiO3 were 62 nm (100 shocks) and 55 nm (200 shocks), demonstrating the significant change in morphology and showing that particles have irregular spherical morphology and are agglomerated by shock wave loaded conditions. Moreover, BaTiO3 nanoparticles were shocked after being tested with various concentrations of different gases at a temperature of 200°C. Under shock loaded conditions, the heightened sensing response for ammonia gases was between 5 and 20 ppm; also, sensing properties such as sensitivity, response, and recovery time indicated that BaTiO3 nanoparticles are a good potential ammonia gas sensing material for real-time sensor applications with enhanced characteristics.

Distribution Properties of the 6.7 GHz Methanol Masers and Their Surrounding Gases in the Milky Way

An updated catalog consisting of 1092 6.7 GHz methanol maser sources is reported in this work. Additionally, the NH3 (1, 1), NH3 (2, 2), and NH3 (3, 3) transitions were observed toward 214 star-forming regions using the Shanghai Tianma radio telescope in order to examine the differences in physical environments, such as the excitation temperature and column density of molecular clouds associated with methanol masers on the Galactic scale. Statistical results reveal that the number of 6.7 GHz methanol masers in the Perseus arm is significantly lower than that in the other three main spiral arms. In addition, the Perseus arm also has the lowest gas column density among the main spiral arms traced by the NH3 observations. Both findings suggest that the Perseus arm has the lowest rate of high-mass star formation compared to the other three main spiral arms. We also observed a trend in which both the luminosity of the 6.7 GHz methanol masers and the ammonia gas column density decreased with the galactocentric distance. This finding indicates that the density of material in the inner Milky Way is generally higher than that in the outer Milky Way. This further suggests that high-mass stars are more easily formed at the head of the spiral arms. Furthermore, we found that the column density of ammonia gas is higher in the regions on the arms than in the inter-arm regions, supporting that the former is more likely to be the birthplace of high-mass stars.

RANCANG BANGUN SMART CLOSED HOUSE PADA PETERNAKAN AYAM BROILER

This research aims to enhance the growth performance of broiler chickens through the implementation of a smart closed house system. The prototype coop, with dimensions of 150 cmx 80 cm x 50 cm, has been successfully realized by integrating DHT22 and MQ135 sensors withexhaust fan and water pump actuators. The system is controlled by ESP32 DEVKIT, Long Range(LoRa) communication, and the Internet of Things (IoT). Collected data is sent to the Firebaseand can be accessed through an Android application. Testing demonstrates that the sensors andactuators operate according to changes in temperature, humidity, and ammonia gas conditionsinside the coop. LoRa communication testing involves sending sensor data (temperature,humidity, and ammonia gas) at distances of 1, 10, 100, 300, 500, and 600 meters. From thetesting of LoRa transceiver data transmission, a character loss percentage of 0% is observed at10 meters, while at 100 meters, there is a character loss percentage of 17.64%. Integration ofdata into Firebase is successful and displayed through the MIT App Inventor application onAndroid devices. Testing of chicken weight data indicates an increase in broiler chicken weight inthe smart closed house coop compared to secondary data from conventional closed house coops.The testing period spans from day 7 to day 21 of the chicken's age. The highest recorded weightis 1031 grams, with the average weight for all chicken samples at the age of 21 days being 940grams, 2.84% higher than the standard data from conventional closed house coops.

Confinement Enrichment Effect in HoMS-BaTiO3 Microwave Gas Sensors for the Detection of 10 ppb-0.55 v/v% Ammonia at Room Temperature.

The construction of ammonia gas sensors with wide detection ranges is important for exhalation diagnosis and environmental pollution monitoring. To achieve a wide detection range, sensitive materials must possess excellent spatial confinement and large active surfaces to enhance gas adsorption. In this study, an ammonia microwave gas sensor with a wide detection range of 10 ppb-0.55 v/v% at room temperature was fabricated by incorporating hollow multishelled-structured BaTiO3 (HoMS-BaTiO3). The effect of the number of shells and the quantity of the sensitive material on the gas-sensing performance was investigated, and two-layered HoMS-BaTiO3 demonstrated the best response at high concentrations (0.15-0.55 v/v%). Conversely, single-layered HoMS-BaTiO3 displayed outstanding performance at low concentrations (10 ppb-0.15 v/v%). The lower the quantity of the sensitive material, the higher the response. This study offers a method for preparing room-temperature ammonia sensors with a wide detection range and reveals the link between the structure and quantity of sensitive materials and gas-sensing performance.

Synthesis and Properties of Eu and Ni Co-Doped ZnS Nanoparticles for the Detection of Ammonia Gas

Zinc sulfide nanoparticles were synthesized successfully via chemical co-precipitation, both in undoped form and co-doped with Europium (Eu) and Nickel (Ni). All prepared samples exhibited cubic zinc blende structure as confirmed by X-ray diffraction (XRD). The average particle size ranged from 3 to 6 nm for both pure and (Eu, Ni) co-doped ZnS, with no alteration in the crystal structure due to Eu and Ni co-doping. However, increasing the Ni dopant concentration (0, 2, 4, & 6 at%) while maintaining a constant Eu concentration (4 at%) led to an enhancement in the crystallite size. This was further validated by transmission electron microscopy (TEM), which showed particle sizes consistent with the XRD findings (3–5 nm). Microscopic analysis via scanning electron microscopy and TEM revealed spherical agglomerated morphology for the (Eu, Ni) co-doped nanoparticles. Energy-dispersive X-ray spectroscopy spectra confirmed the stoichiometric chemical composition of ZnS: Eu, Ni. Photoluminescence studies demonstrated an increased intensity of green luminescence at 6 at% Ni co-dopant concentration. Moreover, the synthesized samples exhibited promising gas sensing properties, particularly towards ammonia gas, with good selectivity. Notably, both pure and (Eu, Ni) co-doped ZnS nanoparticles showed rapid response and recovery times at room temperature, suggesting their potential applicability in gas sensing applications.

Ni(II) triggered sensing and reversible uptake of ammonia by tetrazole based Ni(II) metallogel: A one-pot mechanistic approach

The release of ammonia gas and its removal through traditional approaches is a critical challenge inhibiting the sustainability of chemical industries. The quest to improve sustainability has triggered interest to develop chemoprobe and reusable adsorbent for toxic gases such as ammonia. The present study offers the first example of a novel one-pot synthesis of a stable Ni(II)metallogel (Ni(II)MG) from 1, 4 adiponitrile and sodium azide. The Ni(II)MG is composed of Ni(II) coordinated with four in-situ formed CN-Tz (5-(1H-tetrazol-5-yl)pentanenitrile) ligands and two water molecules forming predominant octahedral geometry. The Ni(II)MG has good strength, and viscoelastic, thixotropic, and self-healing properties. The Ni(II)MG and its xerogel (Ni(II)XG) have been thoroughly characterized and utilized for ammonia sensing and reversible adsorption at ambient condition. The mesoporous nature and presence of hydrogen-bonded water molecules in the pores make this material effective for reversible adsorption of ammonia. The lewis acidic Ni(II) increases the cloud network of hydrogen-bonded water molecules and triggers the coordinated water molecules to activate hydrogen-bonded water molecules for binding the ammonia molecules. The Ni(II) triggered extended hydrogen bonding through coordinated water molecule is also supported by DFT studies. The Ni(II)XG shows good ammonia adsorption capacity (8 mmol/gm) which is confirmed by TPD studies. The properties of Ni(II)XG are found to be intact after ammonia adsorption even after 20 cycles. Hence, it could be a promising low cost, sustainable and reusable material as a chemoprobe for removal of ammonia.

Development of a pH-responsive intelligent label using low molecular weight chitosan grafted with phenol red for food packaging applications

In this study, we successfully developed a screen-printed pH-responsive intelligent label using low molecular weight chitosan grafted with phenol red (LCPR) as a colorant for screen printing ink. The LCPR was synthesized via a Mannich reaction, and its successful grafting was confirmed through FT-IR, UV–vis, and NMR spectroscopy. The LCPR exhibited lower crystallinity and thermal stability compared to low molecular weight chitosan (LC) and demonstrated zwitterionic behavior. To create intelligent labels, the LCPR-based ink was efficiently printed on cotton substrates with high resolution. The label exhibited remarkable sensitivity to buffer pH solutions and ammonia gas, leading to distinctive color changes from orange to red to purple. Additionally, the label showed excellent reversibility, storage stability, and leaching resistance to different food simulant solutions. The label was utilized to monitor shrimp freshness, successfully detecting a noticeable color shift upon spoilage. These findings highlight the significant potential of the LCPR-based label as an intelligent food packaging solution, offering pH-responsiveness and color stability for qualitative freshness detection of protein-rich food.

A simple and environmentally friendly method for preparing graphitic carbon nitride with high specific surface area

Developing a simple and environmentally friendly method to prepare graphitic carbon nitride (g-C3N4) with a high specific surface area remains challenging. This letter reports a molten pretreatment method for preparing g-C3N4 (M−g−C3N4) and compares it to the traditional calcination method used to prepare g-C3N4 (T-g-C3N4). M−g−C3N4 possessed similar crystal and chemical structures to T-g-C3N4. It also exhibited a more mesoporous structure and nitrogen vacancies due to the production of ammonia gas during the molten pretreatment of urea, resulting in a 5.6-fold increase in its specific surface area. M−g−C3N4 demonstrated superior adsorption and photocatalytic degradation towards Rhodamine B than T-g-C3N4.

Enhanced room temperature ammonia sensing using Ti2VC2Tx double-transition-metal MXenes: experimental and theoretical insights

Double-transition-metal (DTM) MXenes are potentially multifunctional materials with greater compositional and structural tunability than mono-transition-metal (MTM) MXenes, enabling controllable formation of defects and controllable tuning of material properties. Herein, we investigate Ti2VC2Tx's ammonia gas sensing via experiments and theoretical calculations. Ti2VC2Tx exhibited a notable response, exceeding 25 %, to 100 ppm ammonia at room temperature with rapid response/recovery times of 4 s/16.2 s. Furthermore, the Ti2VC2Tx sensor shows exceptional ammonia selectivity, attributed to closer adsorption distances and higher adsorption energies of ammonia molecules. This study broadens the application area of DTM MXenes and further demonstrates the potential of MXene materials for gas sensing.