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Ammonia (NH3) has been suggested as a fuel to attain zero carbon emissions. However, dealing with ammonia needs careful studies to reveal its limits as a suitable and promising fuel for broad applications within large power requirements. Chemical reaction mechanisms, widely employed in the modeling of these applications, are still under development. Therefore, this review is aimed to shed light on the current mechanisms available in the literature, highlighting modeling parameters that directly affect reaction rates which in turn govern the performance of each reaction mechanism. The key findings denote that most of the reaction mechanisms have poor performance when predicting combustion characteristics of ammonia flames such as laminar flame speed, ignition delay time, and nitrogen oxide emissions (NOx). In addition, none of the mechanisms have been optimised efficiently to predict properly experimental measurements for all these combustion characteristics. For example, Duynslaegher's mechanism perfectly predicted the laminar flame speed at lean and stoichiometric conditions, while Nakamura's reaction mechanism worked properly at rich conditions for the estimation of laminar flame speed. Although the aforementioned mechanisms achieved good estimation in terms of laminar flame speed, they showed poor performance against NO mole fractions. Similarly, Glarborg's (2018) mechanism properly estimated NO mole fractions at lean and stoichiometric flames while Wang's mechanism performed well in rich conditions for such emissions. Other examples are presented in this manuscript. Finally, the prediction performance of the assessed mechanisms varies based on operating conditions, mixing ratios, and equivalence ratios. Most mechanisms dealing with blended NH3 combinations gave good predictions when the concentration of hydrogen was low, while deteriorating with increasing hydrogen concentrations; a result of the shift in reactions that require more research.

The production of ammonia (NH 3 ) from nitrogen sources involves competitive adsorption of different intermediates and multiple electron and proton transfers, presenting grand challenges in catalyst design. In nature nitrogenases reduce dinitrogen to NH 3 using two component proteins, in which electrons and protons are delivered from Fe protein to the active site in MoFe protein for transfer to the bound N 2 . We draw inspiration from this structural enzymology, and design a two-component metal-sulfur-carbon (M-S-C) catalyst composed of sulfur-doped carbon-supported ruthenium (Ru) single atoms (SAs) and nanoparticles (NPs) for the electrochemical reduction of nitrate (NO 3 - ) to NH 3 . The catalyst demonstrates a remarkable NH 3 yield rate of ~37 mg L -1  h -1 and a Faradaic efficiency of ~97 % for over 200 hours, outperforming those consisting solely of SAs or NPs, and even surpassing most reported electrocatalysts. Our experimental and theoretical investigations reveal the critical role of Ru SAs with the coordination of S in promoting the formation of the HONO intermediate and the subsequent reduction reaction over the NP-surface nearby. Such process results in a more energetically accessible pathway for NO 3 - reduction on Ru NPs co-existing with SAs. This study proves a better understanding of how M-S-Cs act as a synthetic nitrogenase mimic during ammonia synthesis, and contributes to the future mechanism-based catalyst design., (© 2024 Wiley-VCH GmbH.)

To develop novel intelligent indicator films, the mixture of anthocyanin (BWA), polyvinyl alcohol (PVA) and sodium alginate (SA) were spun into PVA/SA/BWA nanofiber films with BWA concentration of 0 %, 5 %, 10 %, and 15 % (based on PVA and SA) via electrospinning technology. The results showed that the BWA was sensitive to pH and was controlled release from films. With increasing BWA concentration, the fiber diameter, tensile strength, and elongation at break gradually decreased, while water contact angle, thickness, moisture content, and antioxidant properties gradually increased. The electrospinning films exhibited high sensitivity to ammonia with rapid color changes in 1 s and excellent color reversibility and color stability within 21 d. The application for shrimp packaging showed that the colorimetric response of the films was closely related to the changes in pH, total volatile basic nitrogen (TVB-N), and total viable count (TVC) of shrimp. This suggests that the prepared films are promising in application for intelligent packaging., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Nitrogen (N 2 ) conversion to ammonia (NH 3 ) in a mild condition is a big chemical challenge. The whole-cell diazotrophs based biological NH 3 synthesis is one of the most promising strategies. Herein, the first attempt of photoelectrochemical-microbial (PEC-MB) biohybrid is contributed for artificial N 2 fixation, where Azotobacter vinelandii (A. vinelandii) is interfaced directly with polydopamine encapsulated nickel oxide (NiO) nanosheets (NiO@PDA). By virtue of excellent bio-adhesive activity, high conductivity, and good biocompatibility of PDA layer, abundant A. vinelandii are effectively adsorbed on NiO@PDA to form NiO@PDA/A. vinelandii biohybrid, and the rationally designed biohybrid achieved a record-high NH 3 production yield of 1.85   µmol h -1 /10 8 cells (4.14 µmol h -1 cm -2 ). In addition, this biohybrid can operate both under illumination with a PEC model or in dark with an electrocatalytic (EC) model to implement long-term and successional NH 3 synthesis. The enhancement mechanism of NH 3 synthesis in NiO@PDA/A. vinelandii biohybrid can be ascribed to the increase of nicotinamide adenine dinucleotide-hydrogen (NADH) and adenosine 5-triphosphate (ATP) concentrations and over expression of nitrogen-fixing genes of nifH, nifD and nifK in nitrogenase. This innovative PEC-MB biohybrid strategy sheds light on the fundamental mechanism and establishes proof of concept of biotic-abiotic photosynthetic systems for sustainable chemical production., (© 2024 Wiley‐VCH GmbH.)

While air stripping combined with acid scrubbing remains a competitive technology for the removal and recovery of ammonia from wastewater streams, its use of strong acids is concerning. Organic acids offer promising alternatives to strong acids like sulphuric acid, but their application remains limited due to high cost. This study proposes an integration of air stripping and organic acid scrubbing with bipolar membrane electrodialysis (BPMED) to regenerate the organic acids. We compared the energy consumption and current efficiency of BPMED in recovering dissolved ammonia and regenerating sulphuric, citric, and maleic acids from synthetic scrubber effluents. Current efficiency was lower when regenerating sulphuric acid (22 %) compared to citric (47 %) and maleic acid (37 %), attributable to the competitive proton transport over ammonium across the cation exchange membrane. Organic salts functioned as buffers, reducing the concentration of free protons, resulting in higher ammonium removal efficiencies with citrate (75 %) and malate (68 %), compared to sulphate (29 %). Consequently, the energy consumption of the BPMED decreased by 54 % and 35 % while regenerating citric and maleic acids, respectively, compared to sulfuric acid. Membrane characterisation experiments showed that the electrical conductivity ranking, ammonium citrate > ammonium malate > ammonium sulphate, was mirrored by the energy consumption (kWh/kg-N recovered) ranking, ammonium sulphate (15.6) < ammonium malate (10.2) < ammonium citrate (7.2), while the permselectivity ranking, ammonium sulphate > ammonium citrate > ammonium malate, aligned with calculated charge densities. This work demonstrates the potential of combining organic acid scrubbers with BPMED for ammonium recovery from wastewater effluents with minimum chemical input., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Gladys Mutahi reports financial support was provided by Netherlands Enterprise Agency. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Herein, we develop a novel method using gas chromatography-ion mobility spectrometry (IMS) with an ammonia dopant for the determination of volatile N -nitrosamines in meat products. The IMS system was implemented with Fourier deconvolution multiplexing to simultaneously improve the resolving power and sensitivity. The ammonia dopant mitigated the formation of N -nitrosamine dimer ions, suppressing the ionization of interferents and shifting the reactant peak from hydrated protons to hydrated ammonium ions. The ammonium adduct product ions of N -nitrosamines were confirmed using time-of-flight mass spectrometry. The instrument limits of detection and quantitation for nitrosamines were 0.78-1.79 and 2.60-5.82 ng/mL, respectively, with recoveries between 71.39% and 110.59% using a simple water distillation method. The developed method showed satisfactory performance when applied to the detection of nitrosamines in various meat products.

Enzymatic nanomotors harvest kinetic energy through the catalysis of chemical fuels. When a drop containing nanomotors is placed in a fuel-rich environment, they assemble into ordered groups and exhibit intriguing collective behaviour akin to the bioconvection of aerobic microorganismal suspensions. This collective behaviour presents numerous advantages compared to individual nanomotors, including expanded coverage and prolonged propulsion duration. However, the physical mechanisms underlying the collective motion have yet to be fully elucidated. Our study investigates the formation of enzymatic swarms using experimental analysis and computational modelling. We show that the directional movement of enzymatic nanomotor swarms is due to their solutal buoyancy. We investigate various factors that impact the movement of nanomotor swarms, such as particle concentration, fuel concentration, fuel viscosity, and vertical confinement. We examine the effects of these factors on swarm self-organization to gain a deeper understanding. In addition, the urease catalysis reaction produces ammonia and carbon dioxide, accelerating the directional movement of active swarms in urea compared with passive ones in the same conditions. The numerical analysis agrees with the experimental findings. Our findings are crucial for the potential biomedical applications of enzymatic nanomotor swarms, ranging from enhanced diffusion in bio-fluids and targeted delivery to cancer therapy., (© 2024. The Author(s).)

Herein, Mg/Al-loaded sludge-based biochar was prepared via electro-assisted impregnation. The structure and chemical analysis of modified sludge-based biochar (MgSBC-0.5(@Al) showed that the material was loaded with MgO and Al2O3. The specific surface area of MgSBC-0.5(@Al) was 11.27 times higher than that of unmodified sludge-based biochar (SBC). The simultaneous adsorption performance of MgSBC-0.5(@Al for ammonia nitrogen (NH4+-N) and phosphate phosphorus (PO43--P) was studied. The maximum adsorption capacities of MgSBC-0.5(@Al for NH4+-N and PO43--P at 298 K were 65.19 and 92.10 mg·g-1, respectively, 4.45 and 6.28 times higher than those of SBC. The external and internal elemental compositions of the modified and unmodified biochar specimens were quantitatively characterized using inductively coupled plasma mass spectrometry, X-ray photoelectron spectroscopy, and X-ray fluorescence spectrometry. The results emphasized the importance of Mg-loading for NH4+-N and PO43--P capture. MgO was mainly loaded on the surface of biochar, enabling adsorption through chemical reactions. Analysis showed that the adsorption of NH4+-N and PO43--P on the modified biochar proceeded simultaneously through multiple mechanisms. Particularly, the adsorption of NH4+-N and PO43--P occurred through the precipitation of struvite and physical adsorption, with PO43--P also adsorbed through the formation of MgHPO4 and CaHPO4. Other data indicated that Al, Ca, and Fe had a trapping effect on the adsorbate. Importantly, the biochar after adsorption could be used as a soil amendment., Competing Interests: NO authors have competing interests., (Copyright: © 2024 Wang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Ceria with surface solid frustrated Lewis pairs (FLPs), formed by regulating oxygen vacancies, demonstrate remarkable ability in activating small molecules. In this work, we extended the application of FLPs on CeO 2 (110) to the selective catalytic reduction of NO by NH 3 (NH 3 -SCR), finding a notable enhancement in performance compared to ordinary CeO 2 (110). Additionally, an innovative approach involving H 2 treatment was discovered to increase the number of FLPs, thereby further boosting the NH 3 -SCR efficiency. Typically, NH 3 -SCR on regular CeO 2 follows the Eley-Rideal (E-R) mechanism. However, density functional theory (DFT) calculations revealed a significant reduction in the energy barriers for the activation of N-O and N-H bonds under the Langmuir-Hinshelwood (L-H) mechanism with FLPs present. This transition shifted the reaction mechanism from the E-R pathway on regular R-CeO 2 to the L-H pathway on FLP-rich FR-CeO 2 , as corroborated by the experimental findings. The practical application of FLPs was realized by loading MoO 3 onto FLP-rich FR-CeO 2 , leveraging the synergistic effects of acidic sites and FLPs. This study provides profound insights into how FLPs facilitate N-H/N-O bond activation in small molecules, such as NH 3 and NO, offering a new paradigm for catalyst design based on catalytic mechanism research.

Recent concerns surrounding climate change and the contribution of fossil fuels to greenhouse gas (GHG) emissions have sparked interest and advancements in renewable energy sources including wind, solar, and hydroelectricity. These energy sources, often referred to as "clean energy", generate no operational onsite GHG emissions. They also offer the potential for clean hydrogen production through water electrolysis, presenting a viable solution to create an environmentally friendly alternative energy carrier with the potential to decarbonize industrial processes reliant on hydrogen. To conduct a full life cycle analysis, it is crucial to account for the embodied emissions associated with renewable and nuclear power generation plants as they can significantly impact the GHG emissions linked to hydrogen production and its derived products. In this work, we conducted a comprehensive analysis of the embodied emissions associated with solar photovoltaic (PV), wind, hydro, and nuclear electricity. We investigated the implications of including plant-embodied emissions in the overall emission estimates of electrolysis hydrogen production and subsequently on the production of synthetic ammonia, methanol, and Fischer-Tropsch (FT) fuels. Results show that average embodied GHG emissions of solar PV, wind, hydro, and nuclear electricity generation in the United States (U.S.) were estimated to be 37, 9.8, 7.2, and 0.3 g CO 2 e/kWh, respectively. Life cycle GHG emissions of electrolytic hydrogen produced from solar PV, wind, and hydroelectricity were estimated as 2.1, 0.6, and 0.4 kg of CO 2 e/kg of H 2 , respectively, in contrast to the zero-emissions often used when the embodied emissions in their construction were excluded. Average life cycle emission estimates (CO 2 e/kg) of synthetic ammonia, methanol, and FT-fuel from solar PV electricity are increased by 5.5, 16, and 49 times, respectively, compared to the case when embodied emissions are excluded. This change also depends on the local irradiance for solar power, which can result in a further increase of GHG emissions by 35-41% in areas of low irradiance or reduce GHG emissions by 21-25% in areas with higher irradiance.

The presence of light hydrocarbons (HCs) in diesel exhaust, specifically C 3 H 6 , significantly affects the performance of the state-of-the-art Cu-SSZ-13 zeolite NH 3 -SCR catalysts. It also leads to the formation of highly toxic HCN, posing risks to the environment and human health. In this work, the highly toxic HCN formation is inhibited, and the C 3 H 6 resistance of Cu-SSZ-13 is improved by secondary metal modification via doping with rare earth/transition metal elements. Upon introduction of C 3 H 6 , the activity of Cu-SSZ-13 significantly decreases at medium-high temperatures. This is primarily due to the competitive reaction between C 3 H 6 and NH 3 , which compete for the NH 3 reductant required in the NH 3 -SCR reaction, resulting in the production of HCN. The unfavorable effect is alleviated on the modified catalysts due to their enhanced oxidation capabilities toward C 3 H 6 and the HCHO intermediate, facilitating the complete oxidation of C 3 H 6 to CO x . This inhibits the undesirable partial oxidation reaction between C 3 H 6 and NH 3 , thereby improving the activity of Cu-SSZ-13 at medium to high temperatures and significantly reducing the formation of highly toxic HCN.

The need to identify ammonia is necessary because of its harmful effects on the environment and humans. In this study, a colorimetric method was also developed for the detection of ammonia using silver nanoparticles (AgNPs) synthesized with the green approach. Biosynthesis of AgNPs was performed by silver nitrate as a silver precursor and Smyrnium cordifolium extract as a reducing and stabilizing agent. Plant extract was studied by FTIR and LC/Mass techniques. The optimization of the effective parameters was carried out with central composite design according to silver nitrate concentration, plant extract volume, pH, and temperature. Biosynthetic nano-silver was characterized with XRD, EDS/EDX, FE-SEM, FTIR, TGA, and DLS methods. The AgNPs was validated for ammonia colorimetric detection. Biosynthesis of AgNPs were increased in 20 mM AgNO 3 , 5 ml Smyrnium cordifolium extract, pH 10, and the temperature of 70 °C. Crystal form of AgNPs characterized with XRD at 2Ѳ value of 38.34°, 44.19°, 64.74°, and 77.59° and spherical shape highlighted in the range between 77.8 and 93 nm. Plant extract consisted of polyphenol (phenolic acid, flavonoid, and terpenoid), fatty acid, amino acid, sugar, purine, and organic acid. AgNPs were used for colorimetric detection of ammonia by shifting the λmax from 580 to 490 nm. A method for ammonia detection was set up, with linear range of 0.5-200 ppm, detection limit of 0.028 ppm and recovery level of 96.3 ± 6.5%. In conclusion, a new biosynthetic method by specified local plant was developed to propose a simple and sensitive colorimetric method for soluble ammonia detection., (© 2024. The Author(s).)

This study explores the electrochemical properties of the carbonaceous Allende CV3 meteorite, focusing on its potential as a Fe-based catalyst derived from Mackinawite iron sulfide for electrocatalytic reactions facilitating nitrogen (N 2 ) fixation into ammonia. Through comprehensive analysis, we not only monitored the evolution of key compounds such as CN - , sulfur/H 2 S, H 2 and carbonyl compounds, but also identified potential reagent carriers, indicating significant implications for the Strecker synthesis of amino acids in space environments. Initial examination revealed the presence of polypeptides, notably sequences including dimer Ala-α-HO-Gly, pentamer Gly 3 -Ala 2 , and hexamer Gly 4 -(HO-Gly) 2 . These discoveries greatly enhance our understanding of astrobiological chemistry, offering valuable insights into prebiotic processes and the potential presence of life-building blocks throughout the universe., (© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)

Nitrogenase converts nitrogen in the air to ammonia. It is often regarded as the second most important enzyme in nature after photosystem II. The mechanism for how nitrogenase is able to perform the difficult task of cleaving the strong bond in N 2 is debated. It is known that for every electron that is donated to N 2 , two ATP are hydrolyzed. In the experimentally suggested mechanism, the activation occurs after four reductions of the ground state, but there is no suggestion for how the enzyme uses the hydrolysis energy to perform catalysis. In the theoretical mechanism, it is suggested that hydrolysis is used to reduce the electron donor. In previous papers, the steps leading to the activation of N 2 in the so-called E 4 state has been investigated, using both the experimental and theoretical mechanism, showing that only the theoretical one leads to agreement with EPR observations for E 4 . In the present paper, the four steps following E 4 , leading to the release of two ammonia molecules, are described using the same methodology as used in the previous studies.

Microbe-driven ammonia nitrogen removal plays a crucial role in the nitrogen cycle and wastewater treatment. However, the rational methods and mechanisms for boosting nitrogen conversion through microbial domestication are still limited. Herein, a combined alkali-photocatalytic stimulation strategy was developed to activate the Halomonas shizuishanensis DWK9 for efficient ammonia nitrogen removal. The strain DWK9 selected from saline-alkaline soil in Northwestern China possessed strong resistance to stress of saline-alkaline environment and free radicals, and was abundant in nitrogen conversion genes, thus is an ideal model for advanced microbial domestication. Bacterial in the combined alkali-photocatalytic stimulation group achieved a high ammonia nitrogen conversion rate of 67.5 %, 10 times outperforming the non-stimulated and single alkali/photocatalytic stimulation control groups. Morphology analysis revealed that the bacteria in the alkali-photocatalytic stimulated group formed a favorable structure for bioelectric transfer. Remarkably, the domesticated bacteria demonstrated improved electrochemical properties, including increased current capacity and lower overpotentials and impedance. Prokaryotic transcription genetic analysis together with qPCR analysis showed upregulation of denitrification-related metabolic pathway genes. A novel FAD dependent and NAD(P)H independent energy mode has been proposed. The universality and effectiveness of the as-developed combined alkali-photocatalytic microbial domestication strategy were further validated through indicator fish survival experiments. This work provides unprecedented degrees of freedom for the exploration of rational microbial engineering for optimized and controllable biogeochemical conversion., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A new method for rapid and facile fabrication of homoporous films with high volatile amine sensitivity was developed. First, red cabbage anthocyanin was encapsulated in ethyl cellulose to form water-in-organic (W/O) emulsion. Afterward, the W/O emulsion was rapidly dried using the supporting matrix Magnolia Grandiflora Linn leaf vein at 60% relative humidity and 50 °C to form a colorimetric film with regular hexagonal pores with an average side length of about 23 μm. The films exhibited good sensitivity to ammonia (NH 3 ), dimethylamine, and trimethylamine, with limit of detection of 0.26, 0.24, and 0.38 μM, respectively, and high stability when stored in high humid environments. An obvious color change of the films from pink to green was clearly observed during the freshness monitoring of pork, chicken, salmon, and shrimp. Thus, this work offered a novel and reliable method for the development of porous films for food freshness monitoring.

The management of reverse osmosis (RO) concentrate remains a challenging task for operators of Landfill Leachates Treatment Plants. In this article we suggest an integrated treatment scheme for RO concentrate that combines solar distillation, struvite precipitation to reduce ammonia content of the distillate and biological treatment of the supernatant either with mixed cultures of bacteria or with microalgae. Experiments in a pilot-scale solar still, equipped with underfloor heating system, showed that the production rate of the distillate ranged up to 3.17 L/d m 2 . The distillate was characterized by elevated average concentrations of ammonium nitrogen; 2028 mg/L and 1358 mg/L in the two experiments conducted, respectively. A decreasing trend on concentrations of NH 4 + -N was noticed during these experiments, while the opposite was observed for COD. Struvite recovery experiments showed that the optimum Mg:NH 4 :PO 3 ratio was that of 2:1:5.8. Under these conditions, the NH 4 + -N removal reached 88%. Further treatment of the process supernatant into a 4-L hybrid sequencing batch reactor with biocarriers and activated sludge achieved NH 4 + -N removal higher than 98% in Phases C and D, where 450 and 600 mL of supernatant were added, respectively. Similar removal was also observed in a 2-L bioreactor with microalgae Chlorella sorokiniana when 150 mL of struvite supernatant were added (Phase B) while further increase of the amount of added supernatant to 200 mL resulted to a sharp stop of NH 4 + -N consumption (Phase C). Calculations for a landfill serving 20,000 inhabitants and a daily RO concentrate production of 6 m 3 /d showed that the required area for the construction of the solar still was 1893 m 2 and the volumes of the hybrid and the microalgae reactor were 54 m 3 and 60 m 3 , respectively. The recovered solid material of struvite process, after characterization for heavy metals and organic micropollutants, could be reused to the fertilizers industry., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Oil sands process-affected water (OSPW), generated by surface mining in Canada's oil sands, require treatment of environmentally persistent dissolved organic compounds before release to the watershed. Conventional chemical and mechanical treatments have not proved suitable for treating the large quantities of stored OSPW, and the biological recalcitrance of some dissolved organics may not be adequately addressed by conventional passive treatment systems. Previous work has evaluated photocatalytic treatment as a passive advanced oxidation process (P-AOP) for OSPW remediation. This work expands upon this prior research to further characterize the effects of water chemistry on the treatment rate and detoxification threshold. Under artificial sunlight, buoyant photocatalysts (BPCs) detoxified all OSPW samples within 1 week of treatment time with simultaneous treatment of polycyclic aromatic hydrocarbons, naphthenic acid fraction components (NAFCs), and un-ionized ammonia. Overall, these results further demonstrate passive photocatalysis as an effective method for treatment of OSPW contaminants of potential concern (COPCs)., Competing Interests: Declaration of competing interest T.M.C.L., Z.W.Y., and F.G. declare ownership stakes in H2nanO Inc., a company with financial interest in the subject matter of this work, as well as inventorship on a BPC patent application (PCT/IB2017/056505, US16/343,298) assigned to H2nanO. T.P., A.B., and T.W. work for COSIA member companies that produce materials and waste streams that are represented by the ones reported in this research. The other authors declare no potentially competing conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Smart packaging material capable of real-time monitoring of food freshness is essential for ensuring food safe. At present, colorimetric ammonia-sensing smart film often possesses issues with complicated production, high cost, and inferior long-term colour stability. Herein, Zinc‑copper bimetallic organic framework (ZnCu-BTC, BTC = 1,3,5-benzenetricarboxylate acid) nanorods with colorimetric ammonia-responsiveness were synthesized by adopting facile aqueous solution method, which were then explored as nano inclusions in potato starch/polyvinyl alcohol (PS/PVA) composite film towards developing high-performance smart packaging material. The results demonstrated that the introduction of ZnCu-BTC nanorods within PS/PVA brought about remarkable improvement in blend compatibility, accompanied by a boost in tensile strength to 47.2 MPa, as well as enhanced ultraviolet (UV) blocking efficacy (over 95.0 %). Additionally, the barrier properties of PS/PVA film against water vapor and oxygen were fortified due to the addition of ZnCu-BTC. More importantly, the developed PS/PVA/ZnCu-BTC nanocomposite film displayed satisfactory antibacterial activity (over 99 %) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), favorable colorimetric ammonia-sensing ability, and long-term colour stability. The ZnCu-BTC incorporated PS/PVA nanocomposite film could grant real-time detection of prawn freshness decline via remarkable colour change, indicating vast promise for smart food packaging applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Ammonia is a colorless gas, yet it can be fatal if inhaled or ingested in high enough concentrations. Herein, a solid-state colorimetric smart wool (WL) sensor for ammonia was developed. Common hop (Humulus lupulus L.) is a natural resource of spectroscopical dyestuff known as xanthohumol (XN). Wool fabrics were dyed with different concentrations of xanthohumol extract using the high-temperature high-pressure method in the presence of a mordant. The coloration parameters and absorption spectra were employed to explore the yellow-to-white colorimetric shift of the wool fabric after it was exposed to aqueous ammonia. The wool fabric showed an excellent detection limit of 5 to 125 ppm. When the ammonia concentration was increased, the absorbance spectra demonstrated a hypsochromic shift from 498 nm to 367 nm. This could be attributed to changes in the molecular structure of xanthohumol that happen owing to intramolecular charge delocalization. Using transmission electron microscopy (TEM), the mordant/xanthohumol nanoparticles were measured to have diameters of 15-40 nm. The xanthohumol-finished wool fabrics showed good colorfastness properties. The incorporation of mordant/xanthohumol nanoparticles into wool fabrics showed no negative effects on their stiffness or air-permeability., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A fluorescent hybrid film composed of nitrogen-doped graphene quantum dots (N-GQDs) loaded on halloysite nanotubes (HNTs) (N-GQDs/HNTs nanocomposite) as a sensitive element and polyvinyl alcohol (PVA) as a film-forming matrix was designed for freshness detection. The PVA-N-GQDs/HNTs hybrid film exhibited significantly enhanced fluorescence attributed to the loading of N-GQDs onto the surface of HNTs through electrostatic interactions and hydrogen bonding, effectively reducing their aggregation. The fluorescence of the hybrid film could be quenched by ammonia via photoinduced electron transfer (PET), with good linearity in the range of 20 ppm to 500 ppm ammonia and a limit of detection (LOD) of 0.63 ppm. In addition, the hybrid film was applied to monitor the freshness of seawater fish and freshwater fish stored at refrigeration and room temperature to evaluate the practicality of this approach. The developed hybrid film showed promise for nondestructive and on-site monitoring of fish spoilage., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Graphene transistor sensors, with advantages such as facile surface functionalization and high sensitivity, have gained extensive research interest in gas detection applications. This study fabricated back-gated graphene transistors and employed a hydroxylation scheme for the surface functionalization of graphene. On the basis of the interaction mechanisms between gas molecules and graphene's electrical properties, a compact electrical kinetics model considering the gas-solid surface reaction of graphene transistors is proposed. The model can accurately predict the electrical kinetic performance and can be used to optimize sensor characteristics. The bias condition of a higher response can be rapidly determined. In addition, the density of hydroxyl groups on graphene is revealed to be the direction of improvement and a key factor of response. Hence, the gas detection capacity of sensors with varying densities of hydroxyl groups was assessed concerning ammonia gas, and design technology co-optimization (DTCO) is realized. Measurement results show that the sensor with 70 s of hydroxylation time has a 7.7% response under 22 ppm ammonia gas.

Continuous monitoring of ammonia (NH 3 ) in humid environments poses a notable challenge for gas sensing applications because of its effect on sensor sensitivity. The present work investigates the detection of NH 3 in a natural humid environment utilizing ReS 2 /Ti 3 C 2 T x heterostructures as a sensing platform. ReS 2 nanosheets were vertically grown on the surface of Ti 3 C 2 T x sheets through a hydrothermal synthetic approach, resulting in the formation of ReS 2 /Ti 3 C 2 T x heterostructures. The structural, morphological, and optical properties of ReS 2 /Ti 3 C 2 T x were investigated using various state-of-the-art techniques, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, zeta potential, Brunauer-Emmett-Teller technique, and Raman spectroscopy. The heterostructures exhibited 1.3- and 8-fold increases in specific surface area compared with ReS 2 and Ti 3 C 2 T x , respectively, potentially enhancing the active gas adsorption sites. The electrical investigations of the ReS 2 /Ti 3 C 2 T x -based sensor demonstrated enhanced selectivity and superior sensing response ranging from 7.8 to 12.4% toward 10 ppm of NH 3 within a relative humidity range of 15-85% at room temperature. These findings highlight the synergistic effect of ReS 2 and Ti 3 C 2 T x , offering valuable insights for NH 3 sensing in environments with high humidity, and are explained in the gas sensing mechanism.

The impact of water on catalyst activity remains inconclusive due to its dependence on the specific reaction environment. To maximize the exploitation of water's promoting effect, we employed ammonia selective catalytic reduction (NH 3 -SCR) as a probe reaction and proposed a phosphorus modification strategy for Cu-ZSM-5 catalysts. The objective of this approach was to construct water-adaptive microstructures through directional arrangement. To investigate the effect of phosphorus on the transformation of framework copper sites in humid environments, we conducted comprehensive characterizations and density functional theory calculation. Results reveal that water molecules cleave the oxygen bridges between phosphorus oxide and copper, leading to the formation of active isolated [Cu(OH)] + groups and phosphate. The phosphate species weaken the interaction between exchanged Cu 2+ groups and the zeolite framework, leading to the generation of highly migratory hydrated Cu 2+ species. This work will potentially guide the rational design of water-adaptive catalysts for gas pollution abatement in a humid environment.

A fill-and-draw flushing test on a landfill cell containing MSW waste was carried out to examine the operational viability of this method for accelerating the flushing of contaminants and landfill stabilisation. During the fill cycle, 800 m 3 of water containing the tracer bromide was pumped into the base of a 0.44 ha landfill cell, resulting in the estimated saturation of 9,400 m 3 of waste. Abstraction took place in two phases, during which 1,100 m 3 of tracer/leachate was recovered. Samples of leachate were analysed for the tracer, electrical conductivity and indigenous solutes chloride and ammonia. Tracer recovery was between 63 and 72 % for bromide. An estimated 227 kg of ammonia and 575 kg of chloride were removed. Test data was used to calibrate a 1D, dual-porosity model involving advection in a mobile zone, and diffusion into 'blocks' of a less mobile zone. The model fitted well to the early time data, whereas later data appears to have been affected by recharge. The results of this trial demonstrate the possibilities of the 'fill-and-draw' concept using the basal leachate drainage system of landfills as a potential accelerated landfill remediation technique. However, modelling results suggest low contaminant removal efficiency. Including a pause between the fill and the draw cycles improves mass removal., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Tristan Rees-White reports financial support was provided by Engineering and Physical Sciences Research Council. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.]., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Water microdroplets containing dissolved ammonia (30-300 μM) are sprayed through a copper oxide mesh with a 200 μm average pore size, resulting in the formation of nitrate (NO 3 - ) and the release of molecular hydrogen (H 2 ). The products result from a redox process that takes place at the liquid-solid interface through contact electrification, where no external potential is applied. Oxidation is initiated by superoxide radical anions (O 2 - ) that originate from the oxygen in the air surrounding the microdroplets and from the hydroxyl radicals (OH • ) originating from the water-air interface. Two spin traps (TEMPO and DMPO) capture these radicals as well as NH 2 OH +• , HNO, NO • , NO 2 • , and NOOH, which are detected by mass spectrometry. We also directly observed N 2 O 2 -• by the same means. We found that the hydrogen atom from the ammonia molecule can be set free not only in the form of H • but also as H 2 , which is detected using a residue gas analyzer. The oxidation process can be significantly enhanced by a factor of 3 when the sprayed microdroplets are irradiated with ultraviolet light (265 nm, 5 W). 35% of 300 μM ammonia can be degraded within 20 μs, and the nitrate conversion rate is estimated to be 15 nmol·mg -1 ·h -1 .

We report a novel system consisting of a redox reaction and a highly efficient reductase-like nanozyme, silica-palladium nanoparticles (Pd@SiO 2 NPs), as a novel detection platform for fluorometric sensing. In a proof-of-concept demonstration using an oligonucleotide as the detection target, a glass fiber-based sensor is fabricated by covalently conjugating two oligo probes, which are complementary to the adjacent segments of the target oligonucleotide, on Pd@SiO 2 NPs and glass fiber, respectively. In the presence of the target oligonucleotide, the two probes are drawn together by the target through sequence-specific hybridization, bringing the Pd@SiO 2 NPs to the glass fiber. When the glass fiber is subsequently immersed in a mixture of resazurin and ammonia borane solution, the Pd@SiO 2 NPs on the glass fiber trigger the catalytic conversion of resazurin (blue, slightly fluorescent) to resorufin (pink, highly fluorescent) with massive signal amplification, indirectly signaling the presence of the target oligonucleotide. We show that the glass fiber-based fluorometric sensor can detect a target oligonucleotide associated with the BRAF mutation linearly in the concentration range of 20 to 400 pM with a detection limit (LOD) of 15 pM and the specificity to differentiate targets with single-base difference. These results demonstrate a new frontier for the development of a sensitive, specific, and inexpensive nonenzyme-based fluorometric sensing platform as an alternative to conventional enzyme-based assays.

Leachate emanating from landfills contains ammonia which may cause serious health effects on living things. An effectively designed clay barrier should not allow the contaminant to infiltrate the soil and groundwater systems. The utilization of certain industrial by-products in engineered landfill barriers, not only reduces the need for conventional liner materials but also helps in sustainable waste management. This study investigated the hydraulic conductivity, unconfined compressive strength, compaction, and adsorption characteristics of lithomargic clay blended with an optimum percentage of bentonite (10%) and granulated blast furnace slag (15%) permeated with ammonia. The results revealed that increasing the content of granulated blast furnace slag decreased the maximum dry density while increasing the optimum moisture content. In comparison to lithomargic clay, the hydraulic conductivity of the amended soil liner permeated with ammonia decreased from a value of 3 × 10 -8  m/s to 5 × 10 -10  m/s. The unconfined compressive strength of the amended soil specimens showed an increasing trend with curing times (i.e., 0, 14, 28, and 56 days). The batch adsorption results revealed that Freundlich and Langmuir's isotherm fits the equilibrium adsorption data and the adsorption of ammonia on clay liner follows non-linear behaviour. Overall, the experimental results implied that lithomargic clay blended with 10% bentonite and 15% granulated blast furnace slag can be used as an impermeable soil reactive barrier in engineered landfills., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Guanidine is a chemically stable nitrogen compound that is excreted in human urine and is widely used in manufacturing of plastics, as a flame retardant and as a component of propellants, and is well known as a protein denaturant in biochemistry 1-3 . Guanidine occurs widely in nature and is used by several microorganisms as a nitrogen source, but microorganisms growing on guanidine as the only substrate have not yet been identified. Here we show that the complete ammonia oxidizer (comammox) Nitrospira inopinata and probably most other comammox microorganisms can grow on guanidine as the sole source of energy, reductant and nitrogen. Proteomics, enzyme kinetics and the crystal structure of a N. inopinata guanidinase homologue demonstrated that it is a bona fide guanidinase. Incubation experiments with comammox-containing agricultural soil and wastewater treatment plant microbiomes suggested that guanidine serves as substrate for nitrification in the environment. The identification of guanidine as a growth substrate for comammox shows an unexpected niche of these globally important nitrifiers and offers opportunities for their isolation., (© 2024. The Author(s).)

Water is essential for the survival of all living things; however, its extensive use in agriculture, high-tech manufacturing, energy production, and the rapid development of the chemical and petroleum industries has led to significant contamination, making water pollution a major concern today. Ammonia is one of the most harmful contaminants present in water, posing significant environmental and health risks that require appropriate remediation methods. To remove ammonia from contaminated water, we employ Carbon Nanotubes (CNTs) and Activated Carbon (AC). To ensure appropriate metal impregnation on the adsorbents, Fe, Al, Ag, and Cu were impregnated into both CNT and AC, followed by extensive characterization using Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), and Energy Dispersive X-rays (EDX). To optimize ammonia removal from water, several parameters were adjusted, including pH, dose amount, contact time, shaking speed, and temperature. Astonishingly, the highest removal efficiency of 40% was achieved with a 1 g dosage at pH 10.5 and 200 RPM, while silver oxide had a lower removal rate of 10% under the same conditions. Temperature additionally had a significant impact, with removal percentages reaching 40% at 70 °C as compared to 21.5% at 25 °C. Adsorption isotherms were used to analyze the experimental data, along with Langmuir and Freundlich's models. Notably, Langmuir produced superior curve fitting, resulting in a correlation factor close to one. Furthermore, kinetic modeling was carried out with 2nd-order and pseudo-2nd-order equations, with the latter responding better according to curve analysis. Because the ammonia removal rate was low, this study indicates the feasibility of implementing an adsorption technique using CNT and AC as a pre-treatment method for this purpose. This approach has the potential for future optimization and deployment in tackling water contamination concerns effectively., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Herein, three g-C 3 N 4 (MCN/TCN/UCN), obtained by the direct pyrolysis of melamine/urea/thiourea respectively, were introduced as supports to optimize the NH 3 -SCR activity of Ce-W-Ti catalyst. Compared to CWT-400-Air, CWT@g-C 3 N 4 (2)-300-N 2 exhibits lower crystalline anatase TiO 2 and larger specific surface area, which improves the dispersion of Ce/W/Ti species on catalysts surface. Furthermore, the introduction of g-C 3 N 4 as supports also contributes to doping C/N elements into Ce-W-Ti catalyst and increases the Ce 3+ /(Ce 3+ +Ce 4+ ) and O α /(O α +O β ) molar ratios on catalyst surface. These all are advantageous to the NH 3 -SCR activity. However, UCN shows better promotional effect than MCN and TCN. This might be mainly attributed to the loose and porous stacked layered fold structure of UCN, the larger BET surface area, higher dispersion of Ce/W/Ti species and moderate weak/medium-strong acid sites of CWT@UCN(2)-300-N 2 . At the same time, the influence of carbon nitride amount, calcination atmosphere and calcination temperature on the NH 3 -SCR activity of CWT@g-C 3 N 4 catalyst were also investigated.

Intelligent food packaging has recently gained significant attention due to the heightened consumer awareness regarding food quality. Although anthocyanins avoid safety issues, the instability and leakage of anthocyanins restrict their utilization in freshness indicator labels. In this study, we introduced an innovative metal-organic framework (UiO-66-NH 2 ) synergistic pH-colorimetric label with fast ammonia-responsive, incorporating sodium alginate, red cabbage anthocyanin, and UiO-66-NH 2 . The cross-linked sodium alginate substrate enabled the label to possess superior insolubility. The microscopic morphology of the labels was intricately analyzed, while their sensitivity was rigorously tested utilizing ammonia as a representative gas. Due to the remarkable UV absorption capability of UiO-66-NH 2 and various molecular interactions with anthocyanins, the label exhibited good UV absorption, enhanced stability, and optimized performance in reducing anthocyanin leakage, ensuring the stability and effectiveness of the labels in practical applications. The prepared label exhibited good specificity for volatile amines and ammonia gases, and robust anti-interference properties, enabling visualization and early detection of shrimp spoilage during storage at different temperatures. The strategy employed in this study presents promising new possibilities for developing intelligent packaging solutions for food products., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The recent global population explosion has increased people's food demand. To meet this demand, huge amounts of nitrogen (N) fertilizer have been applied in the worldwide. However, ammonia (NH 3 ) volatilization is one of the primary factors of N loss from soil after N application causing decrease crop N utilization efficiency and productivity. Incubation experiments were conducted on an acidic clayey soil with two different N sources (urea and anaerobic digestion effluent; ADE), two differently-produced biochars, and three biochar application rates (0%, 0.25%, and 1.0% w/w). Ammonia volatilization was lower from urea (14.0-23.5 mg N kg -1 ) and ADE (11.3-21.0 mg N kg -1 ) with biochar application than those without biochar (40.1 and 26.2 mg N kg -1 from urea and ADE alone, respectively). Biochar application significantly mitigated volatilization and reduction percentages for urea and ADE were 40%-64% and 18%-55%, respectively. 1.0% biochar application mitigated volatilization significantly compared to 0.25% application regardless of N source and biochar types. Possible mechanism for volatilization mitigation for urea and ADE were increased N immobilization by soil microorganisms and accelerated net nitrification rate due to increased soil nitrifying bacteria, respectively. Overall, our results clarified different mechanisms for N volatilization mitigation from different (inorganic vs. organic) N sources with biochar application., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Developing predictive models for iodo-trihalomethane (I-THM) formation in water is needed and valuable to minimize extensive and costly analysis. The main objective of this study was to develop a statistical model for the formation of six types of I-THMs under uniform formation conditions. Prediction of I-THM formation in two different water sources (natural organic matter [NOM] and algal organic matter [AOM]) were comprehensively evaluated during both preformed chloramination and prechlorination followed by ammonia addition conditions. In addition, the prediction of THM10 (sum of six I-THM and THM4) formation was conducted during both oxidation strategies for NOM waters. In total, 460 experimental results were compiled from the literature and our own database. The results showed the coefficient of determination (R 2 ) values for the six I-THM species ranged between 0.53-0.68 and 0.35-0.79 in the preformed NH 2 Cl and perchlorinated NOM waters, respectively. Among all independent variables, the I - exhibited the most significant influence on the formation of all I-THM species in the preformed NH 2 Cl, while SUVA 254 was the most influential parameter for perchlorinated NOM water. When the preformed chloramination was compared with prechlorination followed by ammonia addition, the R 2 value for I-THMs (0.93) was higher than for THM4 formation (0.79) in preformed chloramination. In the prechlorination followed by ammonia addition condition, the model prediction of I-THMs (R 2 = 0.45) formation was lower than THM4 (R 2 = 0.96). Overall, the pH, I - , SUVA 254 , and oxidant type are all played crucial roles in determining the I-THM formation, impacting the overall effectiveness and predictability of the models., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Selective catalytic NH 3 -to-N 2 oxidation (NH 3 -SCO) is highly promising for abating NH 3 emissions slipped from stationary flue gas after-treatment devices. Its practical application, however, is limited by the non-availability of low-cost catalysts with high activity and N 2 selectivity. Here, using defect-rich nitrogen-doped carbon nanotubes (NCNT-AW) as the support, we developed a highly active and durable copper-based NH 3 -SCO catalyst with a high abundance of cuprous (Cu + ) sites. The obtained Cu/NCNT-AW catalyst demonstrated outstanding activity with a T 50 (i.e. the temperature to reach 50% NH 3 conversion) of 174°C in the NH 3 -SCO reaction, which outperformed not only the Cu catalyst supported on N-free O-functionalized CNTs (OCNTs) or NCNT with less surface defects, but also those most active Cu catalysts in open literature. Reaction kinetics measurements and temperature-programmed surface reactions using NH 3 as a probe molecule revealed that the NH 3 -SCO reaction on Cu/NCNT-AW follows an internal selective catalytic reaction (i-SCR) route involving nitric oxide (NO) as a key intermediate. According to mechanistic investigations by X-ray photoelectron spectroscopy, Raman spectroscopy, and X-ray absorption spectroscopy, the superior NH 3 -SCO performance of Cu/NCNT-AW originated from a synergy of surface defects and N-dopants. Specifically, surface defects promoted the anchoring of CuO nanoparticles on N-containing sites and, thereby, enabled efficient electron transfer from N to CuO, increasing significantly the fraction of SCR-active Cu + sites in the catalyst. This study puts forward a new idea for manipulating and utilizing the interplay of defects and N-dopants on carbon surfaces to fabricate Cu + -rich Cu catalysts for efficient abatement of slip NH 3 emissions via selective oxidation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

As an alternative to fossil fuels, there is growing interest in using ammonia in combustion systems, particularly in internal combustion engines. As a competent competitor to hydrogen, it has various advantages. However, adding an ignition promoter such as hydrogen is still necessary to maintain combustion stability. Since the engine using ammonia also suffers from high NO x emissions, in this study, the effects of adding different gases on the performance and emissions of an ammonia-hydrogen dual-fuel engine were numerically investigated. The base engine was a diesel engine whose parameters were accustomed to running with ammonia-hydrogen as fuel. Hydrogen was injected via the port in the intake stage at 180 crank angle degrees (CAD) and mixed with the cylinder charge. Ammonia was directly injected into the cylinder at 350-370 CAD. Different gasses, including argon, nitrogen, carbon dioxide, and oxygen, were injected into the cylinder at various crank angles before, during, and after ammonia injection (330-350 CAD, 350-370 CAD, and 370-390 CAD). A MATLAB code was prepared to solve the governing equations, and the combustion mechanism was implemented in Cantera. The results showed that adding CO 2 before or concurrent with the ammonia injection timing had undesirable impacts on the peak in-cylinder pressure and NO and NO 2 emissions. The O 2 addition had a negative on the emissions. Adding N 2 and Ar concurrently with the ammonia injection (350-370 CAD) could diminish NO and NO 2 emissions without drastically affecting the peak in-cylinder pressure and temperature., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study elucidates the impact of fluctuating influent conditions and in situ ultrasonic wave exposure on the stability of aerobic granular sludge (AGS) in the treatment of simulated wastewater emanating from rare earth mining operations. During a stable influent period spanning from Day 1 to Day 95, the seed granules underwent an initial disintegration followed by a re-granulation phase. The secondary granulation was achieved on Day 80 and Day 40 for the ultrasonic reactor (R1) and the control reactor (R2), respectively. Notably, granules formed in R1 exhibited a more porous structure compared to those generated in R2. Subsequently, when the ammonia nitrogen in the influent oscillated between 100 and 500 mg/L during Days 96-140, both reactors yielded compact and densely structured granules. Nitrogen removal profiles were comparable between the two reactors: the removal efficiencies for ammonia nitrogen and total inorganic nitrogen escalated from 95% and 80%, respectively, during Days 1-95, to 95% and 90%, respectively, post-Day 140. A suite of performance metrics indicated that steady-state granules from R1 outperformed those from R2 across several parameters. Specifically, the nitrification/denitrification rates, and relative abundance of denitrifying bacteria were all higher in granules from R1. Conversely, the relative abundance of nitrifying bacteria was comparable between granules from both reactors. However, R1 granules demonstrated lower sludge concentration and smaller average particle size than their R2 counterparts. In conclusion, the AGS system demonstrated robust resilience to fluctuating ammonia nitrogen, and the application of ultrasonic waves significantly enhanced granular activity while achieving in situ sludge reduction.

Seafood plays a major role in the human diet. During transportation, without proper storage and supply chain, its quality deteriorates easily. The post-harvesting processes such as the storage of food play a crucial role in human health. So it is highly imperative to have a technique for identifying food spoilage earlier to ensure the food safety and security of the consumers. Herein we have developed a highly selective and sensitive fluorescent 'Turn-on' probe 2-amino-5-nitrobenzo [d] thiazol-2-yl) imino)methylphenol ANT based on aggregation induced emission (AIE). ANT molecule possesses both restricted intramolecular rotation (RIR) and excited state intramolecular proton transfer (ESIPT) properties leading to fluorescent enhancement rather than aggregation caused quenching (ACQ). The probe shows high selectivity and sensitivity towards the NH 3 vapor. This probe with the AIE property is employed for the real-time detection of NH 3 in both aqueous and gaseous phases. ANT molecule is deposited on the paper shred by a physical method is utilized to monitor NH 3 vapor from red snapper fish as a real-time sample during its degradation processes. After two days there is a ratiometric color change in the paper shred from yellow to orange for the fish stored at room temperature indicating its rotten and unpalatability nature. Paper shred is reused by immersing it into the tetrahydrofuran (THF), in which it retains its initial color due to deprotonation of NH 3 , keto to enol tautomerism discloses the reusability of the fluorescent probe. Studies carried out using UV-visible and fluorescence spectroscopy infer that the ANT probe has high affinity towards NH 3 vapor., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Titan, the largest moon of Saturn is thought to have the potential to support primordial life. The surface of Titan contains bodies of liquid hydrocarbons, and modelling suggests that an ammonia-water ocean resides deep beneath the surface, both of which have been speculated to support primordial chemistry. Here we present the first evidence that both preformed and self-organised phospholipid vesicles remain stable and can maintain concentration gradients in ammonia-water environments; a fundamental requirement for primordial chemistry and biology to originate. We further reveal the remarkable stability of a diether phospholipid, such as those found in extremophilic bacteria, under these conditions and demonstrate that electron microscopy and tomography are useful tools to investigate macromolecular structure under diverse physico-chemical environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

The behavior of metal ions is commonly studied in pure solvent although, in our daily life, these metals are involved in mixtures of solvents. In the present study, we investigated structures, relative stabilities and temperature dependance of solvated ferrous ion in water-ammonia mixture solvent at 0K and at various temperatures ranging from 25K to 400K. All the calculations are performed at the MN15 level of theory associated with the aug-cc-pVDZ basis set. For deep understanding of binding patterns in solvated ferrous ion in water-ammonia mixture solvent, noncovalent interactions are presented based on the QTAIM analysis using AIMAll. Our results prove that the ferrous ion is more stable when it is solvated by ammonia instead of water. In addition, hydrogen bonds are weakened by the presence of ammonia molecules. The temperature dependence of the different obtained geometries indicates that from s=6 (s is the sum of water and ammonia molecules around the ferrous ion), when the number of water molecules is almost equal to that of ammonia, the structures with coordination number 5 are dominant. However, the coordination number is six when there are a maximum water molecules (rich water solution) or maximum ammonia molecules (rich ammonia solution) around the ferrous ion (for s≥6). The QTAIM analysis shows that there are two coordination bondings and four hydrogen bondings. Furthermore, it is found that the Fe 2+ ⋯N coordination bondings are stronger than the Fe 2+ ⋯O confirming that the ferrous ion prefers to be solvated by ammonia instead of water., Competing Interests: Declaration of competing interest There is no conflict of interest to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The nitrogen transformation during sludge pyrolysis is affected by the dewater conditioner. However, the comparative analysis of the conditioner under identical pyrolysis conditions has been previously absent. In this study, Ca-, Fe- and Al-based conditioners were selected as the representatives. A comprehensive evaluation considering the cost of the conditioners and the product characteristics was conducted. Additionally, the in-situ fixation mechanism of the conditioner on nitrogen-containing gas was concurrently revealed. Among the six conditioners, CaO and AlCl 3 were identified as the top performers, ranking first and second, respectively. Furthermore, Fe/Ca-based conditioners reduced NH 3 and HCN release by 1.5 ∼ 5.53 % and 0 ∼ 1.55 %, respectively, by facilitating the conversion of amine-N to a more stable form in condensable fraction. Fe promoted volatile amine-N cyclization, while Ca encouraged its dehydrogenation. Both Fe/Ca-based conditioners increased 7.5 ∼ 14.8 % nitrogen retention in char, by inhibiting the decomposition of protein-N. Al-based conditioners had little effect on NH 3 and HCN, but contributed to 2.3 ∼ 2.8 % production of stabilized nitrogen in char. The introduction of Cl in Fe/Ca/Al chloride conditioners would promote the decomposition of inorganic ammonium salts to produce NH 3 at 30 ∼ 185 °C. And Cl also reacted with volatiles through electrophilic substitution reaction, leading to the formation of halogenated hydrocarbons in condensable fraction and the release of more NH 3 , HCN, and HNCO at 30 ∼ 465 °C. The findings of this study provide a detailed comparative analysis of various conditioners under uniform conditions and reveal the in-situ fixation mechanism of nitrogen-containing gas. This will provide guidance for the sludge conditioning-dewatering-drying integrated treatment and disposal., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Despite the remarkable developments of the Ugi reaction and its variants, the use of ammonia in the Ugi reaction has long been recognized as impractical and unsuccessful. Indeed, the ammonia-Ugi reaction often requires harsh reaction conditions, such as heating and microwave irradiation, and competes with the Passerini reaction, thereby resulting in low yields. This study describes a robust and practical ammonia-Ugi reaction protocol. Using originally prepared ammonium carboxylates in trifluoroethanol, the ammonia-Ugi reaction proceeded at room temperature in high yields and showed a broad substrate scope, thus synthesizing a variety of α,α-disubstituted amino acid derivatives, including unnatural dipeptides. The reaction required no condensing agents and proceeded without racemization of the chiral stereocenter of α-amino acids. Furthermore, using this protocol, we quickly synthesized a novel dipeptide, D-Leu-Aic-NH-CH 2 Ph( p -F), which exhibited a potent inhibitory activity against α-chymotrypsin with a K i value of 0.091 μM.

Enzymes play a fundamental role in cellular metabolism. A wide range of enzymes require the presence of complementary coenzymes and cofactors to function properly. While coenzymes are believed to have been part of the last universal ancestor (LUCA) or have been present even earlier, the syntheses of crucial coenzymes like the redox-active coenzymes flavin adenine dinucleotide (FAD) or nicotinamide adenine dinucleotide (NAD + ) remain challenging. Here, we present a pathway to NAD + under prebiotic conditions starting with ammonia, cyanoacetaldehyde, prop-2-ynal and sugar-forming precursors, yielding in situ the nicotinamide riboside. Regioselective phosphorylation and water stable light activated adenosine monophosphate derivatives allow for topographically and irradiation-controlled formation of NAD + . Our findings indicate that NAD + , a coenzyme vital to life, can be formed non-enzymatically from simple organic feedstock molecules via photocatalytic activation under prebiotically plausible early Earth conditions in a continuous process under aqueous conditions., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Detecting and distinguishing between hazardous gases with similar odors by using conventional sensor technology for safeguarding human health and ensuring food safety are significant challenges. Bulky, costly, and power-hungry devices, such as that used for gas chromatography-mass spectrometry (GC-MS), are widely employed for gas sensing. Using a single chemiresistive semiconductor or electric nose (e-nose) gas sensor to achieve this objective is difficult, mainly because of its selectivity issue. Thus, there is a need to develop new materials with tunable and versatile sensing characteristics. Phase engineering of two-dimensional materials to better utilize their physiochemical properties has attracted considerable attention. Here, we show that MoSe 2 phase-transition/CeO 2 composites can be effectively used to distinguish ammonia (NH 3 ) and triethylamine (TEA) at room temperature. The phase transition of nanocomposite samples from semimetallic (1T) to semiconducting (2H) prepared at different synthesis temperatures is confirmed via X-ray photoelectron spectroscopy (XPS). A composite sensor in which the 2H phase of MoSe 2 is predominant lacks discrimination capability and is less responsive to NH 3 and TEA. An MoSe 2 /CeO 2 composite sensor with a higher 1T phase content exhibits high selectivity for NH 3 , whereas one with a higher 2H phase content (2H > 1T) shows more selective behavior toward TEA. For example, for 50% relative humidity, the MoSe 2 /CeO 2 sensor's signal changes from the baseline by 45% and 58% for 1 ppm of NH 3 and TEA, respectively, indicating a low limit of detection (LOD) of 70 and 160 ppb, respectively. The composites' superior sensing characteristics are mainly attributed to their large specific surface area, their numerous active sites, presence of defects, and the n-n type heterojunction between MoSe 2 and CeO 2 . The sensing mechanism is elucidated using Raman spectroscopy, XPS, and GC-MS results. Their phase-transition characteristics render MoSe 2 /CeO 2 sensors promising for use in distributed, low-cost, and room-temperature sensor networks, and they offer new opportunities for the development of integrated advanced smart sensing technologies for environmental and healthcare.

Nitrogen dioxide (NO 2 ) is a significant environmental and human health hazard. Current NO 2 sensors often lack sensitivity and selectivity under ambient conditions. This study investigates ammonia pyrolysis modification of monolayer Ti 3 C 2 T x MXene to enhance NO 2 detection at room temperature. Nitrogen-doped Ti 3 C 2 T x demonstrates a substantial improvement in sensitivity, with a response of 8.87% to 50 ppm of NO 2 compared to 0.65% for the original sensor, representing a 13.8-fold increase. The nitrogen-doped sensor also exhibits superior selectivity and linearity for NO 2 under ambient conditions. Theoretical analysis shows that nitrogen incorporation promotes enhanced interaction between Ti 3 C 2 T x and its surface oxygen-containing functional groups through electronic hybridization, resulting in improved adsorption energy (1.80 |eV|) and electron transfer efficiency (0.67 |e|) for NO 2 , thereby enhancing its gas-sensing performance. This study highlights the potential of ammonia pyrolysis-treated Ti 3 C 2 T x MXene for advancing NO 2 sensor technologies with heightened performance at room temperature.

Ambient pressure X-ray photoelectron spectroscopy (APXPS) is combined with simultaneous electrical measurements and supported by density functional theory calculations to investigate the sensing mechanism of tungsten disulfide (WS 2 )-based gas sensors in an operando dynamic experiment. This approach allows for the direct correlation between changes in the surface potential and the resistivity of the WS 2 sensing active layer under realistic operating conditions. Focusing on the toxic gases NO 2 and NH 3 , we concurrently demonstrate the distinct chemical interactions between oxidizing or reducing agents and the WS 2 active layer and their effect on the sensor response. The experimental setup mimics standard electrical measurements on chemiresistors, exposing the sample to dry air and introducing the target gas analyte at different concentrations. This methodology applied to NH 3 concentrations of 100, 230, and 760 and 14 ppm of NO 2 establishes a benchmark for future APXPS studies on sensing devices, providing fast acquisition times and a 1:1 correlation between electrical response and spectroscopy data in operando conditions. Our findings contribute to a deeper understanding of the sensing mechanism in 2D transition metal dichalcogenides, paving the way for optimizing chemiresistor sensors for various industrial applications and wireless platforms with low energy consumption.

In our work, a gravity-driven ceramic membrane bioreactor (GDCMBR) was developed to remove Mn 2+ and NH 3 -N simultaneously through the birnessite water purification layer in-situ construction on the ceramic membrane due to chemical pre-oxidation (powdered activated carbon (PAC)-MnO x ). Considering the trade-off of biofouling and water production, the daily intermittent short-term vertical aeration mode was involving to balance this contradiction with the excellent water purification and improved membrane permeability. And the GDCMBR permeability of operation flux was improved for 5-7 LHM with intermittent short-term vertical aeration. Furthermore, only ∼7 % irreversible membrane resistance (R ir ) also confirmed the improved membrane permeability with intermittent short-term vertical aeration. And some manganese oxidizing bacteria (MnOB) and ammonia oxidizing bacteria (AOB) species at genus level were identified during long-term operation with the contact circulating flowing raw water, resulting in the better Mn 2+ and NH 3 -N removal efficiency. Additionally, the nano-flower-like birnessite water purification layer was verified in ceramsite@PAC-MnOx coupled GDCMBR, which evolute into a porous flake-like structure with the increasing intermittent short-term aeration duration. Therefore, the sustainable and effective intermittent short-term aeration mode in ceramsite@PAC-MnO x coupled GDCMBR could improve the membrane permeability with the satisfactory groundwater purification efficiency, as well as providing an energy-efficient strategy for membrane technologies applications in water supply safety., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

In the current global context, there is a pressing need to curtail greenhouse gas emissions, making the utilization of a coal and zero-carbon energy blend an imperative strategy for reducing carbon emissions from coal-fired power generation. The planar flame burner serves as a tool to simulate the temperature and atmospheric conditions within the reburning zone, facilitating extensive examination of the physical and chemical structural alterations, as well as the nitrogen oxide reduction potential, during NH 3 /CH 4 activation for reburning pulverized coal. Experimental results underscore that blending high-activity fuels optimizes the combustion performance of coal char. Through the addition of NH 3 and CH 4 , the NO reduction capability of coal char is bolstered by approximately 0.67 times compared to sole reliance on recirculating flue gas transport. Furthermore, NH 3 introduction facilitates the conversion of C]O double bonds into C-O single bonds, rendering them more amenable to reduction by NO. While the joint influence of NH 3 and CH 4 does not significantly impact char particle size, it does foster the evolution of N-Q to N-5 and N-6 on the char surface. Furthermore, there was a significant increase in the BET-specific surface area, which rose by 50%. Additionally, the total pore volume increased by approximately 21.43%. The comprehensive understanding of NH 3 and CH 4 modified pulverized coal reburning technology holds significant promise for optimizing power plant operations and mitigating carbon dioxide and nitrogen oxide emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Ammonia recovery from wastewater has positive environmental benefits, avoiding eutrophication and reducing production energy consumption, which is one of the most effective ways to manage nutrients in wastewater. Specifically, ammonia recovery by membrane distillation has been gradually adopted due to its excellent separation properties for volatile substances. However, the global optimization of direct contact membrane distillation (DCMD) operating parameters to maximize ammonia recovery efficiency (ARE) has not been attempted. In this work, three key operating factors affecting ammonia recovery, i.e., feed ammonia concentration, feed pH, and DCMD running time, were identified from eight factors, by a two-level Plackett-Burman Design (PBD). Subsequently, Box-Behnken design (BBD) under the response surface methodology (RSM) was used to model and optimize the significant operating parameters affecting the recovery of ammonia though DCMD identified by PBD and statistically verified by analysis of variance (ANOVA). Results showed that the model had a high coefficient of determination value (R 2  = 0.99), and the interaction between NH 4 Cl concentration and feed pH had a significant effect on ARE. The optimal operating parameters of DCMD as follows: NH 4 Cl concentration of 0.46 g/L, feed pH of 10.6, DCMD running time of 11.3 h, and the maximum value of ARE was 98.46%. Under the optimized conditions, ARE reached up to 98.72%, which matched the predicted value and verified the validity and reliability of the model for the optimization of ammonia recovery by DCMD process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Despite global efforts to manage water eutrophication, the continual release of ammonia nitrogen from sediments maintains the eutrophic state of water bodies, presenting serious challenges to the management. In order to find an efficient method for sediment remediation, the experiment of using signal molecules to enhance the adhesion of microorganisms on zeolite was carried out. Five different zeolitic ammonium adsorptions were examined using two different signal molecules, N-(3-oxohexanoyl)-L-homoserine lactone (OHHL) and N-(β-ketocaproyl)-DL-homoserine lactone (C6), to enhance microbial attachment on two types of zeolites. The results showed that the modified microbial attached Z 1 zeolite reinforced with signal molecule C6 had the best effect. The effect was better in the case of high ammonium adsorption, and the TN removal could reach 7.99 mg·L -1 with an inhibition rate of 90.08%. The ammonia nitrogen removal reached 4.75 mg·L -1 with an inhibition rate of 87.64%, and the ammonia nitrogen and total nitrogen of the overlying water reached the surface III water quality standard. In addition, the addition of the signal molecule increased the zeta potential on the surface of the bacterial colloid. In addition, the amount of protein I in the dissolved organic matter (DOM) fraction increased, improving microbial adhesion ability and facilitating their attachment to the zeolite surface. The signal molecule C6 could increase the zeta potential of microbial surface and promote the production of protein I, thus strengthening the attachment of zeolite biofilm and improving the water quality., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)