Ammonia Gas Treatment Research Articles

Ammonia gas treatment in low cost biological reactor

Ammonia gas contributes to a number of environmental and human health concerns. The use of chalk, a cheap alkalinity source may reduce costs for biological systems. This research studies a closed liquid flow reactor to treat ammonia gas using chalk as biomass media and alkalinity source with high value calcium nitrate fertilizer production.The proposed reactor showed complete ammonia gas removal at high rate (500 mg N/L/day) and with low cost; where chalk dissolution and ammonia gas absorption contributed to alkalinity in the water for nitrification. High calcium ion concentration (up to 10,000 mg Ca2+ as CaCO3/L) showed only minor effects on ammonia absorption and nitrification rate.

Energy metabolism disorder mediated ammonia gas-induced autophagy via AMPK/mTOR/ULK1-Beclin1 pathway in chicken livers

Ammonia gas is a well-known environmental pollution gas, threatening human health. Ammonia gas is also one of the most harmful gases to livestock and poultry for many years. Many studies have demonstrated toxic effect of ammonia gas on animal health, such as eyes, respiratory system, and digestive system. However, the effect of ammonia gas toxicity on chicken livers and underlying molecular mechanism remains unclear. In this study, we selected chicken liver as research object and duplicated successfully ammonia gas poisoning model of chickens. 1-day-old Ross-308 broilers were randomly divided into the control group (the low ammonia gas group), and two treatment groups (the middle ammonia gas group and the high ammonia gas group) (3 replicates per group and 12 chickens per replicate). Ammonia gas concentration in the low ammonia gas group was ≤5 mg/m3 during day 1–42. Ammonia gas concentration in the middle group was set as 10 ± 0.5 mg/m3 during day 1–21, and 15 ± 0.5 mg/m3 during day 22–42). Ammonia gas concentration in the high ammonia gas group was set as 20 ± 0.5 mg/m3 during day 1–21, and 45 ± 0.5 mg/m3 during day 22–42. The ultrastructure of chicken livers was observed. The activities of four ATPases (Na+K+-ATPase, Mg++-ATPase, Ca++-ATPase, and Ca++Mg++-ATPase), the expression of twelve energy metabolism-related genes (HK1, HK2, PK, PFK, PDHX, CS, LDHA, LDHB, SDHA, SDHB, avUCP, and AMPK), as well as the expression of ten autophagy-related genes (PI3K, LC3I, LC3II, Beclin1, SQSTM1, mTOR, ULK1, ATG5, ATG12, and ATG13) were measured to explore the effect of ammonia gas on energy metabolism and autophagy in chicken livers. Our results showed that excess ammonia gas induced mitochondrial and autophagic damage in chicken liver tissue cells. Meanwhile, ATPases activities were inhibited and the expression of energy metabolism-related genes changed during ammonia gas treatment, meaning that excess ammonia gas caused energy metabolism disorder. Furthermore, ammonia gas exposure altered the expression of autophagy-related genes, suggesting that ammonia gas treatment caused autophagy in chicken livers. Moreover, ammonia gas-induced AMPK compensatory up-regulation activated autophagy process through inhibiting mTOR and promoting ULK1. In addition. there were dose-dependent and time-dependent effects on all detected indexes in ammonia gas-caused chicken liver cell damage. Taken together, AMPK/mTOR/ULK1-Beclin1 pathway participated in energy metabolism disorder-mediated autophagic injury caused by ammonia gas exposure in chicken livers.

Poultry House Ammonia Gas Treatment in a Chemical/Biological Reactor at Low Ph

Poultry House Ammonia Gas Treatment in a Chemical/Biological Reactor at Low Ph

Long-term ammonia gas biofiltration through simultaneous nitrification, anammox and denitrification process with limited N2O emission and negligible leachate production

Ammonia is toxic and malodorous gas, which is emitted from agricultural and industrial sources. Most of known ammonia gas treatment methods share the disadvantages of expensive cost, by-product pollution and high energy consumption. In this study, an ammonia gas biotreatment method was developed, through simultaneous nitrification, anammox and denitrification process (SNAD) in a biofilter, which was expected to reduce operation cost, secondary pollution and energy consumption. Ammonia gas was converted to di-nitrogen gas (97.2–99.5%) and nitrous oxide (0.5–1.8%), with the highest ammonia loading rate of 0.173 gNH3/gVSS·d. Removed ammonia was taken up by both nitrification (70.6%) and anammox (29.4%) process. Anammox and denitrification process contributed to about 60% and 40% of di-nitrogen gas production in SNAD system, respectively. N2O emission might be caused by nitrification as well as denitrification processes, but not by anammox process in the reactor. TN removal efficiency achieved up to 99.4%, which suggested negligible leachate production in SNAD system for ammonia gas filtration. Anammox activity was not inhibited after introducing oxygen, which was most likely related to activity of oxygen-consuming ammonia oxidation, nitrite oxidation and denitrification. As far as know, this study is the first evidence for ammonia gas biofiltration with anammox-related technology, which might be a highly efficient and cost effective solution for ammonia gas removal with less energy consumption (<30%), biomass production (∼10%), greenhouse gas emission (70–80%) and wastewater production (100%).

Creating binder-free supercapacitor electrodes from biomass resources: a nitrogen-doped pomelo peel derived carbon foam

We conducted experiments in producing nitrogen-doped carbon foam using pomelo peels as a raw material. Pomelos are a citrus fruit similar in appearance to grapefruit, and native to South and Southeast Asia. Specifically, we fabricated nitrogen-doped pomelo peel derived carbon foam (N-PPCF) by using an ammonia gas treatment. The as-prepared N-PPCF had a high specific surface area of 1,218.5 m2 g−1, an average pore size of 1.36 nm, and a pore volume value of 0.50 cm3 g−1. Additionally, the N-PPCF had a nitrogen content of 8.1%, allowing for a high specific capacitance of 150.1 F g−1 at a density of 1.0 A g−1. Even at 4 A g−1, the N-PPCF still maintained an ideal capacitance of 115.6 F g−1. Ultimately, we believe that nitrogen doped carbon foam is a potential method for treating pomelo peels, and that N-PPCF can function as a potential binder-free supercapacitor electrode.

Creating binder-free supercapacitor electrodes from biomass resources: a nitrogen-doped pomelo peel derived carbon foam

We conducted experiments in producing nitrogen-doped carbon foam using pomelo peels as a raw material. Pomelos are a citrus fruit similar in appearance to grapefruit, and native to South and Southeast Asia. Specifically, we fabricated nitrogen-doped pomelo peel derived carbon foam (N-PPCF) by using an ammonia gas treatment. The as-prepared N-PPCF had a high specific surface area of 1,218.5 m2 g−1, an average pore size of 1.36 nm, and a pore volume value of 0.50 cm3 g−1. Additionally, the N-PPCF had a nitrogen content of 8.1%, allowing for a high specific capacitance of 150.1 F g−1 at a density of 1.0 A g−1. Even at 4 A g−1, the N-PPCF still maintained an ideal capacitance of 115.6 F g−1. Ultimately, we believe that nitrogen doped carbon foam is a potential method for treating pomelo peels, and that N-PPCF can function as a potential binder-free supercapacitor electrode.

Optical, electrical, and photoelectric properties of nitrogen‐doped perovskite ferroelectric BaTiO3 ceramics

AbstractNitrogen‐doped BaTiO3 (BT) ceramics were produced by the solid‐state reaction method in conjunction with ammonia gas treatment. The optical absorption spectra results show that the bandgap of BT ceramic is narrowed after N‐doping, suggesting that the N‐doping is an effective route to increase light absorption. Polar properties measurements indicate that the ferroelectricity of BT ceramic is well maintained after the N‐doping. In addition, the electric‐field–induced strain is prominently improved to ~0.8% after N‐doping, a value superior to that of PZT. Furthermore, the influence of N‐doping on photoelectric properties of BT ceramics was also investigated. Large increase in photoconductivity and fast response to light illumination conditions were observed in N‐doped BT ceramics. This work provides a novel route to enhance the (photo)electric properties of ferroelectric materials.

The effect of Si and Al concentrations on the removal of U(VI) in the alkaline conditions created by NH3 gas

Remediation of uranium in the deep unsaturated zone is a challenging task, especially in the presence of oxygenated, high-carbonate alkalinity soil and pore water composition typical for arid and semi-arid environments of the western regions of the U.S. This study evaluates the effect of various pore water constituencies on changes of uranium concentrations in alkaline conditions, created in the presence of reactive gases such as NH3 to effectively mitigate uranium contamination in the vadose zone sediments. This contaminant is a potential source for groundwater pollution through slow infiltration of soluble and highly mobile uranium species towards the water table. The objective of this research was to evaluate uranium sequestration efficiencies in the alkaline synthetic pore water solutions prepared in a broad range of Si, Al, and bicarbonate concentrations typically present in field systems of the western U.S. regions and identify solid uranium-bearing phases that result from ammonia gas treatment. In previous studies (Szecsody et al. 2012; Zhong et al. 2015), although uranium mobility was greatly decreased, solid phases could not be identified at the low uranium concentrations in field-contaminated sediments. The chemical composition of the synthetic pore water used in the experiments varied for silica (5–250 mM), Al3+ (2.8 or 5 mM), HCO3− (0–100 mM) and U(VI) (0.0021–0.0084 mM) in the solution mixture. Experiment results suggested that solutions with Si concentrations higher than 50 mM exhibited greater removal efficiencies of U(VI). Solutions with higher concentrations of bicarbonate also exhibited greater removal efficiencies for Si, Al, and U(VI). Overall, the silica polymerization reaction leading to the formation of Si gel correlated with the removal of U(VI), Si, and Al from the solution. If no Si polymerization was observed, there was no U removal from the supernatant solution. Speciation modeling indicated that the dominant uranium species in the presence of bicarbonate were anionic uranyl carbonate complexes (UO2(CO3)2−2 and UO2(CO3)3−4) and in the absence of bicarbonate in the solution, U(VI) major species appeared as uranyl-hydroxide (UO2(OH)3− and UO2(OH)4−2) species. The model also predicted the formation of uranium solid phases. Uranyl carbonates as rutherfordine [UO2CO3], cejkaite [Na4(UO2)(CO3)3] and hydrated uranyl silicate phases as Na-boltwoodite [Na(UO2)(SiO4)·1.5H2O] were anticipated for most of the synthetic pore water compositions amended from medium (2.9 mM) to high (100 mM) bicarbonate concentrations.

Effects of alkali treatments on Ag nanowire transparent conductive films

In this study, we employ various alkali materials (alkali metals with different base strengths, and ammonia gas and solution) to improve the conductivity of silver nanowire (Ag NW)-networked films. The alkali treatment appears to remove the surface oxide and improve the conductivity. When applied with TiO2 nanoparticles, the treatment appears more effective as the alkalis gather around wire junctions and help them weld to each other via heat emitted from the reduction reaction. The ammonia solution treatment is found to be quick and aggressive, damaging the wires severely in the case of excessive treatment. On the other hand, the ammonia gas treatment seems much less aggressive and does not damage the wires even after a long exposure. The results of this study highlight the effectiveness of the alkali treatment in improving of the conductivity of Ag NW-networked transparent conductive films.

A life cycle perspective of slurry acidification strategies under different nitrogen regulations

Livestock manure is a major contributor to ammonia and greenhouse gas emissions and treatment technologies such as slurry acidification can be used to reduce both. In this study, life cycle assessment was used to compare impact potentials of slurry acidification at either the pig housing or the field application stage with conventional slurry management. Furthermore, the effects of differences in environmental regulations concerning nitrogen application limits were analysed. The impact categories analysed were terrestrial eutrophication potential, climate change potential, marine eutrophication potential and toxicity potential. Slurry acidification reduced the terrestrial eutrophication potential by 71% for in-house acidification and by 30% for field acidification. Changes in regulatory plant-available nitrogen application limits resulted in changes in climate change potential and marine eutrophication potential, with lower limits favouring in-house acidification. Acidification can substantially reduce the environmental impacts of animal slurry, but the effect depends on the context of the regulatory regime.

Energy Harvesting from Ammonia Gas Treatment Tank in Organic Fertilizer Powder Plant

This paper proposes an ammonia monitoring system that harvests energy to operate in a chicken manure fertilizer plant. The harvesting is done via thermoelectric generators (TEGs) and photovoltaic (PV) cells. The TEGs convert heat energy on the surface of an air treatment tank into electrical energy by using the Seebeck effect. Since the temperature on the surface of the tank is not high, the TEGs can supply low-power loads. The other loads in the proposed system are powered by the PV cells. Energies obtained from TEGs and PV cells are stored in a supercapacitor (SC) and two lithium batteries, respectively. According to our experiment, the maximum power consumption used by the system was 644mW, while the maximum harvested energy was 4.4W on a sunny day. Together with our developed power management mechanism, our experiment showed that the harvested energies could supply enough energy for a device to run continuously while being able to detect abnormal level of ammonia correctly.

Surface modification of activated carbon for enhanced adsorption of perfluoroalkyl acids from aqueous solutions.

The objective of the research was to examine the effect of increasing carbon surface basicity on uptake of perfluorooctane sulfonic (PFOS) and carboxylic acids (PFOA) by activated carbon. Granular activated carbons made from coal, coconut shell, wood, and phenolic-polymer-based activated carbon fibers were modified through high-temperature and ammonia gas treatments to facilitate systematical evaluation of the impact of basicity of different origins. Comparison of adsorption isotherms and adsorption distribution coefficients showed that the ammonia gas treatment was more effective than the high-temperature treatment in enhancing surface basicity. The resultant higher point of zero charges and total basicity (measured by total HCl uptake) correlated with improved adsorption affinity for PFOS and PFOA. The effectiveness of surface modification to enhance adsorption varied with carbon raw material. Wood-based carbons and activated carbon fibers showed enhancement by one to three orders of magnitudes while other materials could experience reduction in adsorption towards either PFOS or PFOA.

Synergetic effects of hydrophilic surface modification and N-doping for visible light response on photocatalytic activity of TiO2

We made attempts to improve photocatalytic activity of TiO2 nanoparticles under visible light exposure by combining additional treatments. N-doping of TiO2 by ammonia gas treatment increased absorbance of visible light. By coating thin film of polydimethylsiloxane, and subsequently vacuum-annealing, TiO2 surface became more hydrophilic, thereby enhancing photocatalytic activity of TiO2. These two treatments were combined for the first time in this work and photocatalytic activity under visible light irradiation exceeded sum of individual effects of N-doping and hydrophilic modification.

Virus-templated visible spectrum active perovskite photocatalyst

In this study, photocatalytically active perovskite strontium titanate (SrTiO3) nanowires are fabricated for the first time using genetically engineered AEEE-M13 phage and metal alkoxide precursors. One newly developed doping approach with an ammonia gas treatment efficiently produced strontium titanate nanowires, which split water and produce hydrogen under visible-light irradiation. The optical absorption of nitrogen-doped strontium titanate can be tuned by varying the processing conditions and lies in the visible spectrum range when treated at 625°C–650°C. The excellent hydrogen evolution rate of these nanomaterials is correlated with both optical absorption and nitrogen doping level.

Improvement of activated carbons as oxygen reduction catalysts in neutral solutions by ammonia gas treatment and their performance in microbial fuel cells

Commercially available activated carbon (AC) powders from different precursor materials (peat, coconut shell, coal, and hardwood) were treated with ammonia gas at 700 °C to improve their performance as oxygen reduction catalysts in neutral pH solutions used in microbial fuel cells (MFCs). The ammonia treated ACs exhibited better catalytic performance in rotating ring–disk electrode tests than their untreated precursors, with the bituminous based AC most improved, with an onset potential of Eonset = 0.12 V (untreated, Eonset = 0.08 V) and n = 3.9 electrons transferred in oxygen reduction (untreated, n = 3.6), and the hardwood based AC (treated, Eonset = 0.03 V, n = 3.3; untreated, Eonset = −0.04 V, n = 3.0). Ammonia treatment decreased oxygen content by 29–58%, increased nitrogen content to 1.8 atomic %, and increased the basicity of the bituminous, peat, and hardwood ACs. The treated coal based AC cathodes had higher maximum power densities in MFCs (2450 ± 40 mW m−2) than the other AC cathodes or a Pt/C cathode (2100 ± 1 mW m−2). These results show that reduced oxygen abundance and increased nitrogen functionalities on the AC surface can increase catalytic performance for oxygen reduction in neutral media.

Comparative Investigation of Photocatalytic Degradation of Toluene on Nitrogen Doped Ta2O5and Nb2O5Nanoparticles

Nb2O5 and Ta2O5 nanoparticles were prepared at a moderate sintering temperature of 700 °C using a solution method. Nitrogen doped Nb2O5 and Ta2O5 were obtained by ammonia gas treatment at 700 °C. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and UV–vis diffuse reflectance spectroscopy. All the materials were used for photocatalytic decomposition of gaseous toluene irradiated with artificial solar light and pure visible light. Most of the materials were multiple crystallites with orthorhombic and monoclinic structures. Tantalum based compounds, undoped (Ta2O5 (lab)) and nitrogen doped (Ta2O5:N (lab)), have shown much better performance than niobium based materials. Ta2O5:N (lab) decomposed gaseous toluene with a rate similar to those of Ta2O5 (lab) and Ta2O5:N (com) in the initial 60 min but at a higher rate at extended time under artificial sunlight. Ta2O5:N (lab) decomposed about 70% toluene with artificial sunlight and 30% with pure visible light (λ = 400 nm). The material also exhibited a very stable performance with artificial sunlight and pure visible light.

Effect of Surface Property of Activated Carbon on Adsorption of Nitrate Ion

In this study, the removal of acidic functional groups and introduction of basic groups/sites on activated carbons (ACs) by outgassing and ammonia gas treatment were respectively carried out to enhance the nitrate ion adsorption in aqueous solution. Then, the relationships between nitrate ion adsorption and solution pH as well as surface charge of AC were investigated to understand the basic mechanisms of nitrate ion adsorption by AC. The result showed that the nitrate ion adsorption depended on the equilibrium solution pH (pHe) and the adsorption amount was promoted with decreasing pHe. The ACs treated by outgassing and ammonia gas treatment showed larger amount of nitrate ion adsorption than that by untreated AC. These results indicated that, since basic groups/sites could adsorb protons in the solution, the AC surface would be charged positively, and that the nitrate ion would be electrically interacted with positively charged carbon surface. Accordingly, it was concluded that basic groups/sites on the surface of AC could promote nitrate ion adsorption.

Geochemical and Geophysical Changes during Ammonia Gas Treatment of Vadose Zone Sediments for Uranium Remediation

Low water content sediments were treated with NH3 gas to evaluate changes in U mobility as a potential field remediation method for vadose zone contamination. Injection of NH3 gas created high dissolved NH3 concentrations that followed equilibrium behavior. High NH3 concentration led to an increase in pH from 8.0 to 11 to 13, depending on the water content and NH3 concentration. The increase in pore water pH resulted in a large increase in pore water cations and anions from mineral‐phase dissolution. Minerals showing the greatest dissolution included montmorillonite, muscovite, and kaolinite. Pore water ion concentrations then decreased with time. Simulations based on initial pore water ion concentrations indicated that quartz, chrysotile, calcite, diaspore, hematite, and Na‐boltwoodite (hydrous U silicate) should precipitate. Electrical resistivity and induced polarization tomography (ERT/IP) was able to nonintrusively track these NH3 partitioning, dissolution, and precipitations processes through changes in conductivity and chargeability. Ammonia treatment significantly decreases the amount of U present as adsorbed and aqueous species in field‐contaminated sediments. In contrast, sediments containing a large fraction of U associated with carbonates generally showed little change. Uranium leaching from sediments containing high Na‐boltwoodite decreased significantly by NH3 treatment, but x‐ray absorption near‐edge structure/extended x‐ray absorption fine structure showed no change in the Na‐boltwoodite concentration. Therefore, NH3 treatment of contaminated sediment acts to decrease the highly mobile aqueous and adsorbed U by incorporation into precipitates and appears to decrease mobility of some existing U precipitates (Na‐boltwoodite) as a result of mineral coating.

Preparation of nitrogen-doped porous carbon by ammonia gas treatment and the effects of N-doping on water adsorption

Nitrogen-doped porous carbons (N-RFCC) were prepared by NH3N2 mixture gas treatment at high temperature during the carbonization process on resorcinol–formaldehyde cryogels. To show the role of N-doping on the adsorption behavior we carried out water adsorption, and it was found that the amount of water adsorbed is directly related to the nitrogen content over the low pressure region (P/P0<0.3). Applying the theoretical water adsorption model, Horikawa–Do (HD) model, to the adsorption isotherms of N-RFCCs, we could analyze the effects of nitrogen-doping on the adsorption mechanism. Although the concentration of functional groups of N-RFCC is almost equal to that of the non-doped RFCC, which was measured by Boehm titration method, the water adsorbed amounts of N-RFCCs over the low pressure region were larger. This is due to part of the doped nitrogen atoms act as functional groups, contributing to the total concentration of functional groups. The saturated concentrations depend on the packing fraction of water molecules, which in turn depends on the pore size. The packing fractions of N-RFCCs are larger than those of RFCCs, and this could be attributed to the high affinity between water clusters and N-doped surfaces, resulting in a reduced hydrophobicity of the surface.

Effect of nitrogen addition on the performance of microbial fuel cell anodes

Carbon cloth anodes were modified with 4(N,N-dimethylamino)benzene diazonium tetrafluoroborate to increase nitrogen-containing functional groups at the anode surface in order to test whether the performance of microbial fuel cells (MFCs) could be improved by controllably modifying the anode surface chemistry. Anodes with the lowest extent of functionalization, based on a nitrogen/carbon ratio of 0.7 as measured by XPS, achieved the highest power density of 938 mW/m(2). This power density was 24% greater than an untreated anode, and similar to that obtained with an ammonia gas treatment previously shown to increase power. Increasing the nitrogen/carbon ratio to 3.8, however, decreased the power density to 707 mW/m(2). These results demonstrate that a small amount of nitrogen functionalization on the carbon cloth material is sufficient to enhance MFC performance, likely as a result of promoting bacterial adhesion to the surface without adversely affecting microbial viability or electron transfer to the surface.