Aqueous NH Research Articles

Parametric investigation of CO2 capture from industrial flue gases using aqueous mixtures of ammonia (NH3) and potassium carbonate (K2CO3)

The industrial sector has a significant contribution to global CO2 emissions. Aqueous mixtures of NH3 and K2CO3 seem to be promising solvents for the capture of CO2 from industrial flue gases. The CO2 capture from simulated industrial flue gases with CO2 between 10%v/v and 30%v/v was evaluated, considering nominal capture rate of CO2 (CCO2) 90%. The effect of pressure on the solvent regeneration was investigated in the range 5–15 bar. Aspen plus software and the Extended UNIQUAC thermodynamic model were used in equilibrium-based calculations. The aqueous mixtures of NH3 - K2CO3 had lower heat of desorption of CO2 than that in aqueous NH3. K2CO3 effect on NH3 slip from the absorption column was influenced by the concentration of CO2 in gas phase and the composition of solvent. The reduction in NH3 slip by K2CO3 was pronounced in solvents with high NH3 content, ≥4.54 mol/kgH2O. The NH3 slip increased by K2CO3 when solvents with low content of NH3 were used. The presence of K2CO3 in solvents with high CO2 loading, ≥0.4, was not beneficial in terms of NH3 slip. The increase in the pressure of regeneration resulted in an increase in the temperature of regeneration and a decrease in the heat duty of the reboiler.

New Attempts to Synthesize Layered Double Hydroxides Intercalated with SO42-/Cs+ Using Co-Precipitation and Exchange Reactions

Layered double hydroxides (LDHs) with the compositions (Cs+/NH4+)0.111[M2+0.667Al0.333(OH)2.0(SO4)0.222] (M2+ = Mn, Zn) and basal distance of ca. 11 Å were obtained by co-precipitating Mn/Al and Zn/Al sulfate salts with aqueous NH3, using excess of Cs2SO4. [Mn0.667Al3+0.333(OH)2]Cl0.333.nH2O and [M2+0.667Al3+0.333(OH)2](NO3)0.333.nH2O (M2+ = Mn, Zn) were also synthesized by co-precipitation, presenting respective basal distances of 8.92 and 7.92 Å. After applying exchange reactions with excess of Cs2SO4, materials with basal distances of ca. 11 Å were obtained, indicating the exchange of chloride and nitrate with sulfate, without incorporation of Cs+. When Na+0.111[M2+0.667Al0.333(OH)2.0(SO4)0.222](M2+ = Mn, Zn) obtained by co-precipitation and having basal distances of ca. 11 Å was exchanged with excess of Cs2SO4, the content of sulfate remained constant and Na+ was partially replaced with Cs+ , but the amount was lower, indicating the probable composition (Na+/Cs+)y[M2+0.667Al0.333(OH)2-y(SO4)y/2(SO4)0.222-(y/2)](M2+ = Mn, Zn), where some of the hydroxide anions were replaced with grafted SO42-.

Interface and electronic structure engineering induced Prussian blue analogues with ultra-stable capability for aqueous NH4+ storage.

Aqueous ammonium ion batteries (AAIBs) are considered potential energy storage solutions due to their faster kinetics, eco-friendliness, and high safety. Yet, appropriate electrode material for AAIBs is in continual investigation. Here, Prussian blue analogues (PBAs), Na0.73Ni[Fe(CN)6]0.88, are applied by a covalent bond assisted engineering with in situ polyaniline (PANI) polymerization. The synthesized PANI/Na0.73Ni[Fe(CN)6]0.88 hybrid (PNFF) inherited the advantages of the high conductivity of PANI and the stability of PBAs. The content of PANI had an effect on the electrochemical performance of PNFF. When served as cathode for AAIBs, the as-prepared PNFF-60 (PNFF with adjusted PANI content) delivers an enhanced reversible capacity of 92.5 mA h g-1 at 100 mA g-1 after 200 cycles. Even at a high current density of 2000 mA g-1, 95.2% capacity retention (1000 cycles) can be achieved by PNFF-60. The ammonium storage mechanism of PNFF-60 is fully investigated by in situ Raman and ex situ XPS/FTIR analysis. Moreover, an aqueous NH4+ full cell is assembled by coupling the polyimide@MXene (PI@MXene) anode, exhibiting durable cycling stability. This work adds to the understanding of constructing PBAs-based hybrid electrodes for ammonium ion storage devices.

Experimental investigation on the oxidation of printing ink wastewater under hydrothermal flames

Printing ink wastewater has a strong color and contains high salinity and high concentrations of complex organic compounds, posting a severe threat to the ecological environment and human health. In this work, supercritical water oxidation of printing ink wastewater is performed within a transpiring wall reactor (TWR) to avoid corrosion and salt plugging issues. The high concentration of organic matter in printing ink wastewater is used to form hydrothermal flames for enhanced degradation. Flame temperatures, gaseous and aqueous products characteristics, as well as the anti-corrosion and salt plugging performance of the reactor, are obtained. A remarkable temperature fluctuation due to the multi-component systems indicates the instability of hydrothermal flame. The salt recovery rate of 94.56% and the integrity of the porous tube inner wall indicate that TWR has a good performance in terms of anti-corrosion and salt plugging. Under typical conditions, the removal rates for chemical oxygen demand, total nitrogen, and color are 99.52%, 70.07%, and 97.89%, respectively. Alkanes, nitrogenous compounds, benzodiazepines, and heterocyclic compounds in the aqueous products, and CO, H2, NH3, and CH4 in the gaseous products are the main intermediate products of printing ink wastewater under hydrothermal flames. Ammonia nitrogen, as the main intermediate product, inhibits the complete oxidation of nitrogenous organic compounds. Additionally, higher KNO3 concentrations promote the complete oxidation of nitrogenous organic compounds, while higher NaOH concentrations can increase the pH value and slightly facilitate degradation. In addition, higher feed flow rates prevent deposition and adhesion of additives that occur at high concentrations.

Conversion of Ammonia to Hydrazine Induced by High-Frequency Ultrasound.

Hydrazine is a chemical of utmost importance in our society, either for organic synthesis or energy use. The direct conversion of NH3 to hydrazine is highly appealing, but it remains a very difficult task because the degradation of hydrazine is thermodynamically more feasible than the cleavage of the N-H bond of NH3 . As a result, any catalyst capable of activating NH3 will thus unavoidably decompose N2 H4 . Here we show that cavitation bubbles, created by ultrasonic irradiation of aqueous NH3 at a high frequency, act as microreactors to activate and convert NH3 to NH species, without assistance of any catalyst, yielding hydrazine at the bubble-liquid interface. The compartmentation of in-situ-produced hydrazine in the bulk solution, which is maintained close to 30 °C, advantageously prevents its thermal degradation, a recurrent problem faced by previous technologies. This work also points towards a path to scavenge . OH radicals by adjusting the NH3 concentration.

Conversion of Ammonia to Hydrazine Induced by High‐Frequency Ultrasound

AbstractHydrazine is a chemical of utmost importance in our society, either for organic synthesis or energy use. The direct conversion of NH3 to hydrazine is highly appealing, but it remains a very difficult task because the degradation of hydrazine is thermodynamically more feasible than the cleavage of the N−H bond of NH3. As a result, any catalyst capable of activating NH3 will thus unavoidably decompose N2H4. Here we show that cavitation bubbles, created by ultrasonic irradiation of aqueous NH3 at a high frequency, act as microreactors to activate and convert NH3 to NH species, without assistance of any catalyst, yielding hydrazine at the bubble–liquid interface. The compartmentation of in‐situ‐produced hydrazine in the bulk solution, which is maintained close to 30 °C, advantageously prevents its thermal degradation, a recurrent problem faced by previous technologies. This work also points towards a path to scavenge .OH radicals by adjusting the NH3 concentration.

Modeling and Simulation for the Production Process of Soda Ash by the Ammonium Sulfate‐Soda Method

AbstractThe ammonium sulfate‐soda method is a procedure that produces soda ash and the by‐product ammonium sulfate, using mirabilite as the raw material. Here, a process for producing soda ash by the ammonium sulfate‐soda method is proposed. Based on the reaction mechanisms occurring in the Na2SO4‐NH3‐CO2‐H2O system and the kinetic‐thermodynamic data of the CO2 absorption process using aqueous NH3, the soda ash production process is modeled and simulated using Aspen Plus. The effects of various process parameters (the concentration of the raw mirabilite solution, the amounts of NH3 and CO2 flowing into the process, and the recycle ratio of CO2 exhausted from the NaHCO3 calciner, etc.) on the process performance are investigated.

Ammonium vanadium oxide framework with stable NH4+ aqueous storage for flexible quasi-solid-state supercapacitor

Aqueous energy storage systems show great promise because of their merits of high safety, low cost and environmentally friendliness. Huge efforts, in recent years, have been focused on these systems employing metal cations as charge carriers. In aqueous rechargeable batteries, a paradigm shift has recently moved to nonmetal ions as charge carriers (e.g.: H+, NH4+). Herein, we report an ammonium vanadium oxide framework (NVO) displaying excellent NH4+ storages. The capacitance and cycle performance of NVO are greatly improved using NH4Cl/PVA gel electrolyte. In three-electrode configuration, at 0.5 A g−1, the NVO electrode delivers a specific capacitance of 339 F·g−1 (610 C·g−1, 169 mAh·g−1) in NH4Cl/PVA electrolyte, which is much higher than the value of 268 F·g−1 (483 C·g−1, 134 mAh·g−1) in NH4Cl electrolyte. It shows 71% capacitance retention after 14,000 cycles in NH4Cl/PVA electrolyte. The intercalation pseudocapacitance and double layer capacitance are contributed to the charge storage mechanism of NVO. The flexible quasi-solid-state NVO//AC hybrid supercapacitor is assembled and displays outstanding electrochemical performances with high capacitance, long lifespan and practical applications with good mechanical stability and flexibility in various bending states and excellent series and parallel performance. This work not only demonstrates that NVO has great potential for NH4+ storages, but also sheds a light on NH4Cl/PVA electrolyte for flexible aqueous NH4+-supercapacitors.

Electrochemical Ammonia Recovery from Anaerobic Centrate Using a Nickel-Functionalized Activated Carbon Membrane Electrode

Ammonia (NH3) recovery from used water (previously wastewater) is highly desirable to depart from fossil fuel-dependent NH3 production and curb nitrogen emission to the environment. Electrochemical NH3 recovery is promising since it can simply convert aqueous NH4+ to gaseous NH3 using cathodic reactions (OH- generation). However, the use of a separated electrode and membrane imposes high resistances to the cathodic reaction and NH3 transfer. This study examined an activated carbon (AC)-based membrane electrode functionalized with nickel to electrochemically recover NH3 from synthetic anaerobic centrate. The membrane electrode was fabricated using nickel-adsorbed AC powder and a polyvinylidene fluoride (PVDF) binder, and the PVDF membrane layer was formed at the electrode surface by phase inversion. The NH3-N recovery flux of 50.3 ± 0.4 gNH3-N/m2/d was produced at 17.1 A/m2 with a recovery solution at pH 7, and NH3-N fluxes and energy consumptions were improved as the recovery solution became acidic (62.2 ± 2.1 gNH3-N/m2/d with 16.0 ± 1.6 kWh/kgNH3-N at pH 2). Increasing PVDF loadings did not impact the electrochemical performances of the Ni/AC-PVDF electrode, but slightly lower (7%) NH3-N fluxes were obtained with higher PVDF loadings. Ni dissolution (3.7-6.0% loss) was affected by the recovery solution pH, but it did not impact the performances over the cycles.

The effect of zinc shape on its corrosion mitigation as an anode in aqueous Zn/MnO2 battery

• Developing of Zn powder and dust electrode for aqueous Zn/MnO 2 battery. • Zn powder with grain sizes >500 µm attenuate its corrosion and dissolution in NH 4 Cl solution. • Assembling of Zn powder or dust (anode) with electrolytic (EMD) or nanostructured (NMD) MnO 2 (cathode) in Zn/MnO 2 cell. • Zn powder (>500 µm)/NMD cell yields a highest output voltage of 1.646 V. • Specific energy (109.722 mWh/g) and the lowest voltage drop of 0.7% after 2 h of discharge. This work gives an insight into how zinc (Zn) anode in the Zn/MnO 2 batteries is corroded depending on its shape (in the form of powder or dust), and how such shape can play a role to attenuate the Zn corrosion and dissolution during an electrochemical process. Indeed, the corrosion of Zn anodes in powder and dust shape was investigated in ammonium chloride aqueous NH 4 Cl solution using open circuit potential (OCP) plot, linear polarization (LP), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) methods. The electrodes were also observed by scanning electron microscopy (SEM) and analyzed using X-ray diffraction (XRD). The results show that the corrosion rate significantly depends on Zn grain size and surface area. In addition, the SEM observations showed clearly some corrosion features on the surface of Zn grains. Furthermore, the XRD analysis confirms the formation of a corrosion layer constituted of ZnO and adsorbed Zn(NH 3 ) 2 Cl 2 molecules. These electrodes, with two distinct shapes, were used as anodes in assembled Zn/MnO 2 batteries with two types of MnO 2 cathode namely nanostructured manganese dioxide (NMD) and electrolytic manganese dioxide (EMD). Discharge tests showed high performance for Zn/MnO 2 cell based on Zn powder (>500 µm) as anode and NMD as a cathode in NH 4 Cl electrolyte, with an output voltage of 1.65 V and specific energy of 109.72 mWh/g after 2 h under 1 mA. Moreover, this cell is the most stable with a voltage drop as low as 0.7% after 2 h of continuous discharge. Such results demonstrate that the assembled Zn/MnO 2 can be used for low cost and high-performance battery with a specific structure and shape of both anode and cathode materials.

Nitrogen isotope fractionations among gaseous and aqueous NH4+, NH3, N2, and metal-ammine complexes: Theoretical calculations and applications

Ammonium (NH4+), ammonia (NH3) and N2 are key nitrogen species in geological nitrogen recycling. NH3 has also been proposed to play an important role in mobilizing base metals in the form of metal-ammine complexes in hydrothermal fluids. The nitrogen isotope fractionation factors among these nitrogen species in aqueous and gaseous phases are essential parameters to trace source signatures and geochemical properties in geological processes. However, the nitrogen isotope fractionation factors for metal-ammine complexes are largely absent, and the few existing nitrogen isotope fractionation factors for the aqueous NH4+ – aqueous NH3 pair show large discrepancy between experimental results and theoretical calculations. In this study, we employed the density functional theory to systematically calculate the nitrogen isotope fractionation factors among the nitrogen species that may occur in a hydrothermal system, i.e., gaseous N2, gaseous and aqueous NH4+ and NH3, and ammine complexes of Co, Zn, Cu, Cd, Ag, Au, and Pt. Based on these new results, the large nitrogen isotope fractionations for the aqueous NH4+ – aqueous NH3 pair observed in previous experimental studies can be well explained by a combined effect of an equilibrium isotope fractionation between aqueous NH4+ and aqueous NH3 and a kinetic isotope fractionation during NH3 degassing from the solution. This suggests that the nitrogen isotopic behavior during NH3 degassing in natural hydrothermal system can be more complicated than previous thought. A numeric model is thus established here to quantify the combined isotopic effect on partial NH3 degassing. Using the new results of metal-ammine complexes, we also tested the hypothesis that nitrogen mobilization could be controlled by copper-ammine complex based on the copper concentration-δ15N relationship previously observed in meta-gabbros.

Fabrication and electrochemical performances of SnO2@C composite materials

SnO2@C composite materials are facilely fabricated by reaction using the gelatin, SnCl4•5H2O and aqueous NH3•H2O by one-step method. Compared to the SnO2, the prepared SnO2@C composite materials show the fabulous improvement about rate performances and cycling performances, when controlling the carbon contents of carbon in SnO2@C composite materials. As an example, SnO2@C-40 shows the cycling performance at 397.7 mAh/g, after carrying out the charge-discharge cycles 500 times at 0.1 A/g. These ameliorated electrochemical performances lead us to consider our provided preparation method is the efficient way to facilitate the application of SnO2@C in fabrication of lithium ion batteries (LIBs) as negative electrode materials.

Common ion effect enhanced Prussian blue analogues for aqueous ammonium ion storage.

In order to meet the growing demand of energy storage for the power grid, aqueous NH4+ batteries are attracting increasing attention as a promising alternative due to their environmental significance, abundant resources, and fast diffusion ability. In this work, FeFe(CN)6 (FeHCF) is synthesized as a cathode material for aqueous NH4+ batteries and Fe2(SO4)3 is utilized as a kind of functional additive in the electrolyte based on the "common ion effect" to enhance its electrochemical performance. The results indicate that the initial capacity of FeHCF is about 80 mA h g-1 with a coulombic efficiency of 97.8%. The retention rate can attain 96.3% within nearly 1000 cycles. Multivariate analysis methods are carried out to characterize the mechanism of FeHCF in aqueous NH4+ batteries. From the practical standpoint, FeHCF has outstanding cycling stability and rate capability, making it feasible to be applied in the power grid.

Boosting Zn2+ and NH4+ Storage in Aqueous Media via In‐Situ Electrochemical Induced VS2/VOx Heterostructures

AbstractAqueous‐ion batteries have received much attention owing to the merits of high safety, low cost, and environmental friendliness. Among potential cathode candidates, transition metal sulfides drew little attention since they suffer from low capacity, low working potential, and fast capacity fading. Here, advantage is taken of the chemical instability of VS2 in aqueous electrolyte to in situ fabricate a heterostructural VS2/VOx material. Benefiting from the internal electric field at heterointerfaces, high conductivity of vanadium sulfide and high chemical stability of vanadium oxides, heterostructural VS2/VOx delivers an enhanced working potential by 0.25 V, superior rate capability with specific capacity of 156 mA h g−1 at 10 A g−1, and long‐term stability over 3000 cycles as Zn2+ storage electrode. In addition, heterostructural VS2/VOx is employed as the cathode for aqueous NH4+ ion storage with high reversible capacity over 150 mA h g−1 and long lifespan over 1000 cycles, surpassing the state‐of‐the‐art materials. VS2/VOx is proved to demonstrate a (de)intercalation process for Zn2+ storage, while a conversion reaction accompanied by insertion is responsible for nonmetal NH4+. The strong insight obtained in this study sheds light on a new methodology of exploring the potential of transition metal sulfides‐based cathode materials for aqueous ion batteries.

Hydrogen bond chemistry in Fe4[Fe(CN)6]3 host for aqueous NH4+ batteries

Low-cost and high-safety aqueous batteries can provide high-value opportunities for grid-scale energy storage. In this article, the electrochemical intercalation of non-metallic charge carrier (NH4+) into iron hexacyanoferrate (Fe4[Fe(CN)6]3) has been systematically analyzed in aqueous NH4+ batteries. Comprehensive discussions are made based on the experimental and calculation results. Multiple testing methods are applied to illustrate the intercalation mechanism, and novel hydrogen bonds formed between NH4+ and N species of Fe4[Fe(CN)6]3 is initiatively proposed for the stabilization of the system, based on the density functional theory (DFT) calculations. Meanwhile, the density of states (DOSs) data of Fe4[Fe(CN)6]3 with and without HN4+ intercalation further indicates the formation of the strong covalent bonds, which is responsible for the good structural stability of the compound. Additionally, a low-cost rocking-chair aqueous NH4+ full cell is assembled based on NH4·Fe4[Fe(CN)6]3 cathode and 3,4,9,10-Perylene-bis(dicarboximide) (PTCDI) anode, which exhibits durable cycling stability (capacity retention of nearly 90% over 300 cycles) as expected for great potential applications in the sustainable batteries.

Dependence of Phosphorus Recovery on Acid Type during Dissolution–Precipitation Treatment of Incineration Ash of Chicken Manure

In order to utilize chicken manure as a source of phosphorus, we used dissolution-precipitation treatment to recover phosphorus from the incineration ash of chicken manure (IACM), which was used as fuel to power a boiler. In order to recover useful phosphorus-containing solids from IACM, it was dissolved into aqueous solutions of either nitric acid, hydrochloric acid, or sulfuric acid to elute phosphorus together with various component elements, followed by the use of aqueous NH3 to form a precipitate containing phosphorus. In using nitric acid and hydrochloric acid, calcium phosphate species such as calcium hydroxyapatite (Ca10(PO4)6(OH)2) and monetite (CaHPO4) were obtained following the precipitation treatment. By contrast, the use of sulfuric acid resulted in the precipitation of magnesium ammonium phosphate (MAP) species such as struvite (MgNH4PO4∙6H2O) and dittmarite (MgNH4PO4∙H2O). Both the calcium phosphate and MAP species can be used as a slow-acting fertilizer containing phosphorus, while the MAP species could be simultaneously used as a slow-acting fertilizer containing nitrogen. It is noteworthy that the calcium phosphate species obtained in the present study was equivalent to phosphate rock, which is widely used as a raw material in phosphorous-based industries, and the natural sources of this material could be depleted in the near future. Though IACM has not been used effectively until now, this new resource shows promise as s viable alternative to the dwindling supply of the natural sources of phosphorus.

An effective non-chromatographic method for the purification of phenanthrolines and related ligands

1,10-Phenanthrolines are widely employed as ligands, but their use on a large scale is constrained by their difficult purification, which usually requires lengthy chromatographic separations. Herein, we describe a purification strategy that takes advantage of the high stability and low solubility of phenanthroline complexes to separate them from the by products of their synthesis. The formation of ZnCl2 complexes was employed, from which the free ligand can be recovered by reaction with aqueous NH3 in a biphasic CH2Cl2/H2O system. The same strategy was also successfully employed to purify related quinolino-guanidine ligands, demonstrating that the procedure is of general applicability.

Fertilizer source and placement influence ammonia volatilization losses from water‐seeded rice systems

AbstractAmmonia volatilization, a primary N loss pathway from rice (Oryza sativa L.) production systems, leads to a reduction in N use efficiency and environmental problems. Ammonia volatilization has not been studied in water‐seeded rice systems or where aqueous NH3 is the primary fertilizer N source. Our objective was to quantify NH3 volatilization from preplant aqueous NH3 and compare it with drilled or broadcast urea. In addition, NH3 volatilization from a topdress N application applied midseason was quantified. This was accomplished with 10 field experiments representing a range of soil types. Preplant N treatments were a zero‐N control, injected aqueous NH3, broadcast urea, and drilled urea all applied at the farmer application rate to a dry soil. For the topdress experiment, the treatments were a zero‐N control and urea or (NH4)2SO4 applied at 34 kg N ha−1. Ammonia volatilization was measured up to 3 and 1 wk after the preplant and topdress N was applied, respectively, using a semi‐open static chamber. Losses due to NH3 volatilization from preplant broadcast urea were significantly higher than from the other other treatments but accounted for <2% of applied N. Losses from aqueous NH3 and banded urea were lower but were significantly greater than from the control. The losses occurred in the first week after flooding. When N was topdressed, 1.5 and 2.6% of applied N were lost via volatilization from urea and (NH4)2SO4, respectively.

Photocatalytic NH3 Splitting on TiO2 Particles Decorated with Pt–Au Bimetallic Alloy Nanoparticles

Photocatalytic splitting of aqueous NH3 into H2 and N2 on semiconductor powders is an important reaction toward on-site production of H2 from NH3, a promising hydrogen carrier for sustainable energ...

Investigating Ammonium By-product Removal for Ureolytic Bio-cementation Using Meter-scale Experiments

Microbially Induced Calcite Precipitation (MICP), or bio-cementation, is a promising bio-mediated technology that can improve the engineering properties of soils through the precipitation of calcium carbonate. Despite significant advances in the technology, concerns regarding the fate of produced NH4+ by-products have remained largely unaddressed. In this study, five 3.7-meter long soil columns each containing one of three different soils were improved using ureolytic bio-cementation, and post-treatment NH4+ by-product removal was investigated during the application of 525 L of a high pH and high ionic strength rinse solution. During rinsing, reductions in aqueous NH4+ were observed in all columns from initial concentrations between ≈100 mM to 500 mM to final values between ≈0.3 mM and 20 mM with higher NH4+ concentrations observed at distances furthest from the injection well. In addition, soil Vs measurements completed during rinse injections suggested that no significant changes in cementation integrity occurred during NH4+ removal. After rinsing and a 12 hour stop flow period, all column solutions achieved cumulative NH4+ removals exceeding 97.9%. Soil samples collected following rinsing, however, contained significant sorbed NH4+ masses that appeared to have a near linear relationship with surrounding aqueous NH4+ concentrations. While these results suggest that NH4+ can be successfully removed from bio-cemented soils, acceptable limits for NH4+ aqueous concentrations and sorbed NH4+ masses will likely be governed by site-specific requirements and may require further investigation and refinement of the developed techniques.