Amount Of Nitrogen Research Articles

Study of microscopic properties and heavy metal solidification mechanism of electrolytic manganese residue-based cementitious materials.

Electrolytic manganese residue (EMR) is a solid waste that contains a significant amount of soluble manganese and ammonia nitrogen, which can pose risks to human health if improperly disposed of. This study aimed to prepare cementitious materials containing abundant ettringite crystals by mixing EMR with various proportions of granulated blast furnace slag (GBFS) and alkaline activators (CaO, Ca(OH)2, clinker, NaOH). The resulting cementitious material not only utilized a substantial amount of EMR but also exhibited comparable strength to ordinary Portland cement. The optimal ratios were determined through mechanical testing. Additionally, the leaching toxicity of cementitious materials was assessed using ICP-MS (inductively coupled plasma mass spectrometer) tests. The microscopic properties, hydration, and mechanism of heavy metal solidification in the cementitious materials were evaluated using XRD (X-ray diffraction), SEM (scanning electron microscope), EDS (energy-dispersive spectrometer), FTIR (Fourier transform infrared spectroscopy), and TG (thermogravimetric) techniques. The results showed that the optimal ratio for the cementitious materials was 60% EMR, 36% GBFS, and 4% Ca(OH)2. The hardened mortar exhibited compressive strengths of 34.43 MPa, 41.3 MPa, and 50.89 MPa at 3 days, 7 days, and 28 days, respectively, with an EMR utilization rate of 60%. The hydration products of EMR-based cementitious materials were C-(A)-S-H, AFt, and ferromanganese compounds, which contribute to the mechanical strength. The Mn2+ and NH4+-N contents of raw EMR were 1220 and 149 mg/L, respectively. Nonetheless, the leaching of Mn2+ and NH4+-N in the alkali-EMR-GBFS system was significantly below the limits set by the Chinese emission standard GB8978-1996. Within this system, C-(A)-S-H and AFt could physically adsorb and displace heavy metals, Ca6Mn2(SO4)2(SO3)2(OH)12·24H2O could replace Al ions with Mn ions, and ferromanganese compounds Fe2Mn(PO4)2(OH)2·(H2O)8 and MnFe2O4 could chemically precipitate Mn2+.

Improving the physiological indices and biological yield of different Atriplex species with organic fertilizers in different irrigation regimes

Because of water crises, the cultivation of forage plants is greatly important in arid and semi-arid regions of the world. In order to study the effect of different organic fertilizers and irrigation regimes on the growth and biochemical responses of different Atriplex species, this experiment was performed as a factorial split with three replications in the city of Bandar Abbas in 2017-2018. The main factor included three irrigation regimes (irrigation at 80, 60, and 40% of field capacity) and the sub-factor were different sources of fertilizer (poultry manure and sheep manure about 5 tons per hectare, and chemical fertilizer) and different species of Atriplex (A. canascens, A. leucoclada, and A. lelentiformis). Based on the results, increasing drought stress increased sodium (Na) and proline of the leaf and decreased the concentration of nitrogen, phosphorus, potassium, and soluble carbohydrates. In irrigation of 40% of field capacity, the highest amount of leaf nitrogen was observed in sheep manure (1.47%), representing a significant increase compared to the chemical fertilizer. In irrigation of 80% of field capacity, the highest amount of leaf phosphorus (0.222%) was observed in chemical fertilizer. The highest levels of catalase and peroxides were obtained in poultry and sheep manure. Also, in the irrigation of 40% of field capacity, poultry manure and then sheep manure could show higher levels of soluble protein in the leaf, respectively. In general, this study showed the successful effects of organic fertilizers on increasing nutrient uptake and physiological traits and improving the biological yield of Atriplex.

Characterization of diamonds synthesized with h-BN doped under high pressure and high temperature

There is a strong interaction between nitrogen and boron in diamonds. In this paper, boron-nitrogen co-doped diamonds were successfully synthesized at 5.6 GPa and 1300–1350 ℃ with Ni-Mn-Co alloy as a catalyst. The effect of nitrogen on boron-doped diamond (BDD) was further investigated by adding the nitrogen getter to the system. The measurement results of the two groups of crystals showed that nitrogen greatly influenced the growth behavior of BDD. A small nitrogen amount in BDDs could accelerate the growth rate and improve the quality of crystals. In contrast, a high nitrogen concentration decreased the growth rate and created macroscopic defects. The Fourier transform infrared spectroscopy (FTIR) results demonstrated the presence of N+ centers in boron-nitrogen co-doped diamonds. X-ray photoelectron spectroscopy (XPS) characterization of boron-nitrogen co-doped diamond confirmed that boron atoms entered the diamond lattice and combined with nitrogen atoms to form B-N bonds. This work reveals the effect of nitrogen on the properties of BDDs and provides insight into the interaction between boron and nitrogen in diamonds.

Isolation and Identification of Microfungi from Diesel Oil Contaminated Soils and Their Physico-Chemical Analysis

Diesel oil contaminated soils were collected and analyzed for various Physico-chemical properties that included moisture content, total carbon, total nitrogen and phosphorus using standard protocol and the data compared from normal uncontaminated soils. Analysis revealed that all 5 samples of diesel oil contaminated soils possessed higher percent of moisture content, greater amounts of total carbon, nitrogen and phosphorus in comparison to non-contaminated control soils. The diesel oil contaminated soils are not suitable for cultivation of agricultural crops. Though, several species of fungi were isolated from diesel contaminated soils but only 6 species of Aspergillus utilized diesel oil as sole carbon and nitrogen source as these grew well and sporulated normally on 2% agar that contained 10% of diesel oil only as nutrient. These included Aspergillus luchuensis, Aspergillus violaceofuscus, Aspergillus niveus, Aspergillus terreus, Aspergillus japonicus, Aspergillus ustus. which also grew well in broth containing 0.5% jaggery (for initial growth) supplemented with 10% diesel oil only which suggest that these species could utilize diesel oil as sole carbon and nitrogen source because no other nutrient other than diesel oil was added into the medium. The role of carbon, nitrogen and phosphorus is soils has been discussed in this paper.

Towards metal-free nitrogen-doped graphene aerogels as efficient electrocatalysts in hydrogen evolution reaction

Graphene-based materials have been researched to substitute traditional Pt-based electrocatalysts in the hydrogen evolution reaction (HER) due to its strong electrical conductivity, easy functionalization, and cheaper synthesis. Doping graphene with heteroatom is a simple way of obtaining original and active electrocatalysts. Moreover, the nitrogen on it had a positive effect on HER performance. By using a reducing agent with nitrogen while synthesising graphene-based aerogels nitrogen-doped catalysts were obtained. In addition, a better reduction rate, higher crystallography parameters and a more porous material structure were reached. The aerogels were synthesised in an one-pot hydrothermal process, in which the graphene sheets were assembled. This was followed by freeze-drying, which fixed the carbon matrix structure. As a result, the final aerogel had a 3D structure that eased mass transfer and enhanced catalytic activity, reaching an overpotential of −10 mAcm−2 at 101 mV vs RHE (η10 = 101 mV). The amount of quaternary type nitrogen generated during synthesis had a strong influence on electrocatalytic behaviour in HER. Then, quaternary nitrogen and surface area (up to 397 m2/g) were maximized to ensure a higher current density. Moreover, an effective aerogel was prepared with half the solvent per batch, as this was essential for expanding the synthesis to an industrial scale. A final calcination step resulted crucial to improve the metal-free aerogel HER performance.

Doping of porous carbons with sulfur and nitrogen markedly enhances their surface activity for formaldehyde removal

The surfaces of phosphoric acid activated carbon, referred to as CG, and steam activated one, referred to as SX, were modified through an introduction of S- and N- groups originated from thiourea. The prepared samples were used for formaldehyde removal at room temperature. Heating at 450, 600 and 950 °C altered both surface chemistry and porosity. The extents of these modifications depended on the type of carbon. Using thiourea as the modifier resulted in an incorporation of significant amounts of nitrogen and sulfur to the carbon matrices. Their speciation depended on the heat treatment conditions. The activity of samples heated at 450 °C was governed by amine groups of thiourea retained on the surface. A further heat treatment converted gradually amine nitrogen into pyridines/pyrroles and quaternary nitrogen, shifting the adsorption mechanism to rather specific interactions than a direct chemical reactivity. Carbons with few times less nitrogen than in their amine-modified counterparts, but in quaternary form and with the small amount of sulfur in thiophenic configurations, regardless the origin, worked as very efficient adsorbents of HCHO. Due to the modification of the carbon matrix electronic structure, resulting in a positive charge on carbon atoms in the vicinity of the heteroatoms incorporated to carbon rings, the density of specific adsorption centers on the surface in larger pores was significantly higher than that in ultramicropores. This markedly contributed to efficient utilization of pores/surface, where heteroatom can exist and where otherwise the dispersive adsorptions forces would be weak, for HCHO removal at ambient conditions.

Identification of Solanum pimpinellifolium genome regions for increased resilience to nitrogen deficiency in cultivated tomato

High-quality crop production with minimal fertilizer inputs is a key goal for the agriculture of the future. Globally, tomato is one of the most important vegetable crops and its intensive production and breeding has been based on the application of large quantities of nitrogen (N) fertilizers. Therefore, the development of N use efficient (NUE) cultivars with low N inputs needs to be addressed. Some variability in plant growth, fruit quality and NUE traits among tomato (Solanum lycopersicum L.) varieties under low N supply has been reported, however, the relevance of wild relatives of tomato has not yet been assessed. In this study, we found that S. pimpinellifolium accession To-937 (SP) may be a suitable resource to increase NUE in tomato. We studied a set of 29 introgression lines (IL) from SP into the Moneymaker cultivar (MM) in different seasons to investigate the potential of SP introgressions to maintain the tomato plant performance during the growth cycle under low N input in greenhouse conditions. We identified specific regions in the SP genome, on chromosomes 1, 3 and 10, involved in the responses to N inputs of fruit production and fruit quality. Notably, the line SP_10-4 maintained vegetative biomass and fruit yield production under limiting N supply. The introgressed region contained putative candidate genes as sucrose phosphate phosphatase (SPP), invertases (INV) and glutamine synthase 1 (GS1) genes, implicated in C and N metabolism. Genomic and expression analyses revealed differences in coding and non-coding sequences as well as in mRNA levels in SP_10-4, suggesting that these genes might well contribute to the reported biomass responses to N. Additionally, line SP_1-4 showed stable fruit amino acid contents under both sufficient and limiting N supplies, indicating that assimilated N partitioning to the fruit is maintained in response to N. Altogether, our results confirmed the suitability of SP as a source of NUE related traits and the interest in the studied ILs for developing new tomato cultivars with improved NUE under sustainable fertilization conditions.

Detection of salmon meat freshness using QCM gas sensor array combined with physicochemical method

Salmon meat is easy to be spoiled during transportation and storage due to its abundant protein and fatty acids. During the spoilage process, the released volatile organic compounds (VOCs) may vary significantly, mainly including trimethylamine (TMA), dimethylamine (DMA), formaldehyde (HCHO), ammonia (NH3). Herein, a gas sensor array based on quartz crystal microbalance (QCM) modified with four carbon-based nanomaterials such as graphene oxide (GO), Mxenes (Ti3C2TX), hydroxylated multi-walled carbon nanotubes (MWCNTs), and graphite oxide alkyne (GOP) was established to detect TMA, DMA, HCHO and NH3 in salmon meat, respectively. Carbon-based materials have the advantages of high specific surface area and high stability, so they have great potential in gas adsorption. It was observed that the QCM sensors modified with four sensing carbon-based materials presented good sensitivity, selectivity and repeatability towards corresponding target gases. Finally, the sensor array composed by aforementioned four sensors were used to analyze freshness of salmon samples. The response matrix was processed by principal component analysis (PCA) for visualization. Further discrimination model was established by quadratic support vector machine (QSVM) and the classification accuracy was 100%. To demonstrate the feasibility of discriminating salmon freshness by gas sensor array, the identification results were correlated with the amount of total volatile base nitrogen (TVB-N) measured by semimicro-Kjeldahl method.

Development of water resources protection planning and environmental design in urban water conservancy landscape based on ecological concept

Abstract With the development of society, water resources are gradually scarce and water pollution is becoming increasingly serious, which would seriously restrict the development of the urban economy. In response to the current problems of water scarcity and severe water pollution, this article will study the key points of urban environmental design development based on ecological concepts. This article will also use ecological concepts to divide water function zones based on different pollution-carrying capacities in different regions, which can be mainly divided into two levels. In the experimental analysis section, the Xiongan New Area will be analyzed. This article randomly selected three regions in the Xiongan New Area and studied the utilization rate of various types of water in these regions. The pollution capacity and main water resources of each region in the functional area were planned and designed. Through experiments, it can be found that based on ecological concepts, it is beneficial to improve the pollutant-carrying capacity of each functional area and reduce the total amount of ammonia nitrogen.

Co-expression network analysis reveals early molecular signatures of nitrate foraging by poplar roots

Nitrogen is an important macronutrient that is essential for plant growth and acts as a signaling molecule. The amount of nitrogen obtained from soil is often insufficient to satisfy plant demands. To cope with nitrogen deficiency, crops use root elongation to expand the available soil space and obtain more nitrogen resources; however, the regulatory mechanism underlying this important adaptation strategy remains unclear. In this study, phenotypic and physiological changes in poplar roots in response to different nitrogen concentrations were monitored. Poplar root elongation was observed under low nitrogen conditions, and physiological indexes related to nitrogen assimilation changed within 2 h. A dynamic transcriptome analysis revealed significant differences at the early stage of nitrogen treatment based on nitrogen availability. According to K-means testing, these differences mainly involved the duration and degree of enrichment of some primary metabolites, consistent with the results of a weighted correlation network analysis. Several TFs, such as MYB2/73/111/116/123, bZIP42/53/60, and NAC083/104, may play important roles in this early response to variation in nitrogen availability. Transcriptional regulatory networks were constructed, and key regulatory elements were identified, such as MYB3, E2F, and DRE-like at 30 min, and ARF, T-box, and SBP-box at 90 min pxMYB56, a TF closely related to a 90-min element, was identified, and root suppression was observed in pxMYB56-overexpressing plants. These results can serve as a valuable resource for dissecting the role of candidate genes promoting root elongation in poplar under low nitrogen concentrations.

Growth Response of Non-Conventional Yeasts on Sugar-Rich Media: Part 2: Citric Acid Production and Circular-Oriented Valorization of Glucose-Enriched Olive Mill Wastewaters Using Novel Yarrowia lipolytica Strains.

The global market for citric acid (CA) is one of the biggest and fastest expanding markets in the food industry. The CA production employing microbial bioprocessing with efficient GRAS strains and renewable waste streams is in line with the European Union binding targets for resource efficiency, sustainable consumption-production, and low-carbon technologies. In this work, the potential of three novel wild-type Yarrowia lipolytica strains (namely LMBF Y-46, LMBF Y-47 and ACA-YC 5033) regarding the production of CA and other valuable metabolites was tested on glucose-based media, and the most promising amongst the screened strains (viz. the strain ACA-YC 5033) was cultured on glucose-based media, in which part of the fermentation water had been replaced by olive-mill wastewaters (OMWs) in a novel approach of simultaneous OMW valorization and bioremediation. In the first part of this study, the mentioned strains were cultured under nitrogen-limited conditions with commercial (low-cost) glucose employed as a sole carbon source in shake-flask cultures at an initial concentration (S0) ≈ of 50 g/L. Variable quantities of secreted citric acid (CA) and intra-cellular compounds (viz. polysaccharides and lipids) were produced. All strains did not accumulate significantly high lipid quantities (i.e., maximum lipid in dry cell weight [DCW] values ≈30% w/w were noted) but produced variable CA quantities. The most promising strain, namely ACA-YC 5033, produced CA up to c. 24 g/L, with a yield of CA produced on glucose consumed (YCA/S) ≈ 0.45 g/g. This strain in stirred tank bioreactor experiments, at remarkably higher S0 concentrations (≈110 g/L) and the same initial nitrogen quantity added into the medium, produced notably higher CA quantities, up to 57 g/L (YCA/S ≈ 0.52 g/g). The potential of the same strain (ACA-YC 5033) to bioremediate OMWs and to produce value-added compounds, i.e., yeast cells, CA, and intra-cellular metabolites, was also assessed; under nitrogen-limited conditions in which OMWs had partially replaced tap water and significant glucose concentrations had been added (S0 ≈ 100 g/L, simultaneous molar ratio C/N ≈ 285 g/g, initial phenolic compounds [Phen0] adjusted to ≈1.0 g/L; these media were similar to the OMWs generated from the traditional press extraction systems) the notable CA quantity of 60.2 g/L with simultaneous YCA/S = 0.66 g/g, was obtained in shake flasks, together with satisfactory phenolic compounds removal (up to 19.5% w/w) and waste decolorization (up to 47.0%). Carbon-limited conditions with Phen0 ≈ 1.0 g/L favored the production of yeast DCW (up to 25.3 g/L), with equally simultaneous interesting phenolic compounds and color removal. The fatty acid profile showed that cellular lipids were highly unsaturated with oleic, linoleic and palmitoleic acids, accounting for more than 80% w/w. This study proposed an interesting approach that could efficiently address the biotreatment of toxic effluents and further convert them into circular-oriented bioproducts.

The use of probiotic in chicken-broilers feeding

Biologically active feed additives of natural origin that do not hurt the body are increasingly used in poultry farming, making it possible to produce safe food products. It is known that probiotics are preparations of microbial origin that manifest their properties through the regulation of intestinal microflora. The primary mechanism of action of probiotics is to populate the gastrointestinal tract with strains of beneficial bacteria that displace opportunistic microflora from the intestinal biocenosis. The experiment aimed to establish the effect of probiotic feed additives on the productivity, slaughter performance, and meat quality of broiler chickens. Following the purpose of the research, a scientific and economic experiment was conducted on two similar groups of broiler chickens of the “Cobb-500” cross from one day to 42 days of age, with 20 heads in each group according to the experiment scheme. The experiment lasted 42 days. With the use of a feed additive in feeding broiler chickens of the 2nd group, the live weight increased by 11.9 % (Р ≤ 0.001) compared to the control group. It was found that under the influence of the supplement, the average daily growth in broiler chickens of the 2nd group was higher by 12.1 %, absolute by 12.2 % (Р ≤ 0.001) compared to control peers during the entire experiment period. In addition, in the 2nd group of broilers, feed consumption per 1 kg of growth is reduced by 8.9 % compared to the control. The use of a feed additive in the feeding of broiler chickens of the 2nd group increases the pre-slaughter live weight by 12.0 % (Р ≤ 0.001), the weight of an uncut carcass by 12.1 % (Р ≤ 0.001), half-cut carcass by 9.9 % (Р ≤ 0.01) and by 13.3 % (Р ≤ 0.001) relative to the control value. With the consumption of the investigated feed additive in broilers of the 2nd group, the level of total moisture in the pectoral muscles increased by 1.3 % (Р ≤ 0.05), and in the femoral muscles, the hygromoisture level was higher by 0.2 % (Р ≤ 0.05) and the amount of nitrogen by 0.2 % (Р ≤ 0.05), compared to the control group.

Mitigating runoff nitrate loss from soil organic nitrogen mineralization in citrus orchard catchments using green manure.

Nitrate-nitrogen (NO3--N) loss is a significant contributor to water quality degradation in agricultural catchments. The amount of nitrogen (N) fertilizer input in citrus orchard is relatively large and results in significant NO3--N loss, compared to cropland. To promote sustainable N fertilizer management, it is crucial to identify the sources of runoff NO3--N loss in citrus orchards catchments. Particularly, we poorly know the sources of NO3--N and the mitigation mechanisms in these areas, which are highly polluted with NO3--N in water bodies. In this study conducted in central China, we conducted a field experiment with four treatments (CK: no N fertilizer; CF: conventional N fertilizer, 371.3kg N ha-1 yr-1 urea; OM: CF with organic manure; GM: CF with legume green manure) and a catchment-scale experiment in two citrus orchards (34.3%; 51.6%) catchments. To determine the source of runoff NO3--N loss, we used the dual isotope tracer method (δ15N and δ18O of NO3-) to identify the sources of NO3--N, and a 15-day incubation experiment to determine the potential and rate of soil N mineralization. Our findings revealed that soil organic nitrogen (SON) mineralization was the primary contributor to runoff NO3--N loss, and soil N mineralization potential (0.65⁎⁎⁎) and rate (0.54⁎⁎⁎) were the key factors impacting NO3--N loss. Interestingly, organic manure significantly increased 29.0% of NO3--N loss derived from SON in the runoff by enhancing soil N mineralization potential (+36.6%) and rate (+77.1%). But green manure mulching significantly reduced the soil N mineralization rate (-18.6%) compared to organic manure application, making it the most effective measure to reduce NO3--N loss (-12.4%). Our study highlights the critical role of regulating SON mineralization in controlling NO3--N pollution in surface waters in citrus orchard catchments.

Improvement of Photocatalytic Degradation of Titanium Dioxide Nanomaterials by Non-metal Doping

Semiconductor photocatalysis is a process that benefits from sunlight to start chemical reactions. In order to take advantage photocatalytic properties of semiconductors and to achieve better performance structural adjustment is needed. In this study, varying amounts of nitrogen were used to modify TiO2 nanostructures using the sol-gel method. The crystalline structure of the synthesized TiO2 nanostructures was studied using the X-ray diffraction (XRD) technique. X-ray photoelectron spectroscopy (XPS) was conducted to analyse the elemental composition of nanomaterials. XPS analyze confirms that nitrogen is introduced into the lattice of TiO2. The photocatalytic degradation of methylene blue (MB) under UV irradiation was employed to assess the photocatalytic performance of the samples. To evaluate degradation, the absorption of MB over time was measured using a UV-Vis spectrophotometer. As a result, the doping process has been found to improve the photocatalytic performance of TiO2, and 0.2% N doped TiO2 nanostructures demonstrated superior photocatalytic activity for photocatalytic degradation of MB.

Study on Corrosion Characteristics of Aluminum Alloy Al3102 in Sulfate-reducing Bacteria Environment and Investigating the Use of Azadirachta indica Leaves Extract in its Control

An effort to understand the corrosion characteristics of aluminium Al3102 alloy in a neutral medium in the presence of Desulfovibrio desulfuricans was made. The corrosion rate increased up to tenfold in the bacterial medium in comparison to the control (abiotic) medium. Scanning electron microscopy (SEM) studies showed substantial sulfate-reducing bacteria (SRB) adhesion on the alloy surface and pit formation. Supplementation of 1000 ppm Azadirachta indica leaves extract decreased corrosion by 82%. Sulfide analysis, SEM, and X-ray photoelectron spectroscopy (XPS) studies showed a significant effect of neem leaf extract (NLE) on bacterial metabolic activity and confirmed the adsorption of the inhibitor molecules on Al3102 surface. Electrochemical impedance spectroscopy studies showed that the NLE formed a highly resistive external layer which protected the alloy surface from the corrosive effects. The gas chromatography-mass spectroscopy studies (GC-MS) showed appreciable amount of esters, terpenoids, heterocyclic nitrogen, sulfur compounds, and organic bromine compounds in NLE.

Scaling up an Electrochemical Nitrogen Recovery Process from Lab Benchtop to Pilot Wastewater Plant

Municipal wastewater and agricultural runoff contain large amounts of reactive nitrogen, which can pollute the environment upon release, leading to harmful algal blooms and poor drinking water quality. At the same time, these reactive nitrogen species are valuable and can be recycled to generate fertilizers and commodity chemicals; it has been estimated that doing so would offset the need for ~30% of global Haber-Bosch ammonia production. For this reason, both removal and recovery of active nitrogen from wastewaters are important goals. An electrochemical separations technique known as Electrochemical Stripping (ECS) has been developed to achieve selective ammonia recovery from wastewater.1 This technique leverages pH swings induced by water-splitting, coupled with appropriate cation- and gas-selective membranes, to remove and recover ammonia nitrogen from wastewaters. ECS has been demonstrated at the benchtop scale with relatively high efficiency (>90% total ammonia nitrogen [TAN] recovery) in various wastewaters, and the effects of certain process variables such as temperature, influent TAN concentration, and gas-permeable membrane material have previously been reported.2 Our goal with this work is to initiate ECS process scale-up by at least 3 orders of magnitude in order to match the scale of municipal wastewater treatment. In order to do this, we set out to build a more complete fundamental process model to inform our design decisions during scale-up. Here we will present results of exploratory tests varying multiple process parameters, including current density, relative electrolyte volumes, reactor residence time, catholyte solution chemistry, and reactor geometry. We then translate these results into a process model comprising thermodynamic relationships as well as kinetic equations, describing both the rates of species generation/consumption as well as transport between reactor compartments. This model, which yields molecular-level insights, is then used in an iterative fashion to first predict performance at small scales under new sets of conditions, and then ultimately inform the design of a ~1000 L/day ECS reactor at a pilot-scale wastewater treatment facility.In addition, we will discuss findings from stakeholder engagement conducted in parallel to lab-scale tests, indicating utility limitations, priorities, needs for certain effluent specs, desired product specs, cost bounds, and details around hydrogen coproduct handling. These discussions additionally feed into design decisions and are crucial for eventual technology deployment.

Studies on integrated plant nutrient supply system for maximizing the growth and yield of rice (Oryza sativa L.)

The research was conducted to determine how rice growth and productivity would be impacted using graded amounts of inorganic fertilizer in conjunction with organic manures and bio fertilizer in rice variety TRY 3 at Annamalai University's Experimental Farm, Tamil Nadu, India. This investigation on crop response-based fertilizer prescriptions together within Integrated Plant Nutrient Supply System (IPNSS) was conducted during 2021 and 2022. Different quantities of nitrogen, green manure, pressmudbiocompost, goat manure, seaweed extract, and phosphate-solubilizing bacteria (PSB) were employed in the eight treatments. The treatments were replicated thrice, and the field trial was laid out using randomised block design (RBD). According to the research outcome, among the different treatments, 100% RDN + 25% N as Pressmudbiocompost + PSB resulted in higher morphological characters, including plant height (124.11cm), leaf area index (4.84), dry mater production (13012 kg/ha), number of tillers/hill (33.30), chlorophyll content (30.66), root length (28.39 cm) and volume (23.64 cc/hill) and yield characteristics, including productive tillers/hill (31.30), grains/panicle (153.70), and filled grain/panicle (147.40),grain yield (6693 kg/ha) and straw yield (7865 kg/ha)of rice. Multiple parameters in the control treatment scenario indicated lower production and inadequate growth and development. The study revealed that application of100% RDN + 25% N as Pressmudbiocompost + PSB could be considered a better option for achieving the growth and yield attributes of TRY 3 under transplanted condition.

Nitrogen isotope marker experiments in austenitic stainless steel for identification of trapping/detrapping processes at different temperatures

Expanded austenite – austenitic stainless steel containing a colossal amount of nitrogen in solid solution – is still some kind of conundrum with the nitrogen atom transport from the surface into the bulk being enhanced for higher nitrogen content. At the same time, atomic ordering due to an enhanced affinity between chromium and nitrogen is observed.Here, nitrogen transport experiments are performed at different temperatures using 14N and 15N as isotopic tracers. The depth distribution of each of these isotopes as well as the total nitrogen content is investigated with time-of-flight secondary ion mass spectrometry (ToF-SIMS) and glow discharge optical emission spectroscopy (GDOES), respectively. In parallel, phase information is obtained using in situ X-ray diffraction (XRD) during nitriding (for time-resolved data) and during sputter depth profiling (for depth-resolved data).During nitriding, no delayed transport of nitrogen, i.e. trapping, is observed for the expanded austenite. However, as soon as CrN precipitates are formed, nitrogen trapping is a dominant factor with an almost perfect correlation between precipitation and trapping. Cluster ion analysis in SIMS confirms this effect with the abundance of Cr2+ ions significantly increased compared to FeCr+ ions in the presence of precipitation. As nitrogen transport and CrN formation occur in parallel at higher temperatures, further experiments to separate the CrN formation at higher temperatures from the nitrogen transport at lower temperatures have been performed.

The association of natural hydrogen and nitrogen: The ammonium clue?

It is generally accepted that hydrogen is generated by ferrous iron oxidation and/or water radiolysis but no attempt has been done so far to explain the origin of the nitrogen that is associated to ‘hydrogen systems’ such as those located in Brazil and Oman and New Caledonian ophiolites.We carried out 25–300 °C geochemical equilibrium calculations on model water and water-mineral systems including ammonium (NH4+) to see if this ion could be a ‘precursor’ in the generation of hydrogen and/or nitrogen. The considered minerals of the water-mineral systems were the magnetite-hematite or fayalite-magnetite-quartz redox-buffering assemblages.The water systems including NH4+ only or NH4+ and ferrous iron co-generate hydrogen and nitrogen through the ammonium decomposition reaction:NH4+ = 1.5 H2 + 0.5 N2 + H+In the water-mineral systems, hydrogen is generated by the magnetite and fayalite ferrous iron oxidation while nitrogen is generated independently by the hematite and magnetite ferric iron reduction by NH4+:3 Fe3+ + NH4+ = 0.5 N2 + 3 Fe2+ + 4 H+With magnetite-hematite, the produced gas is mainly composed of nitrogen. At low temperature with fayalite-magnetite-quartz, the produced gas is mainly composed of hydrogen; approaching 300 °C, and with a sufficient initial ammonium stock, a significant amount of nitrogen is produced to form a mixed gas.If we consider low (magnetite-hematite) or high (fayalite-magnetite-quartz) reducing conditions occurring respectively within the central or peripheral zones of the hydrogen systems, NH4+ passing through and reacting with these two kinds of redox environments could explain why the central zones release mainly hydrogen (with some amounts of nitrogen) and why mainly nitrogen is emitted at the peripheries.

Transport and distribution of residual nitrogen in ion-adsorption rare earth tailings

A large amount of nitrogen remains in ion-absorption rare earth tailings with in-situ leaching technology, and it continually ends up in groundwater sources. However, the distribution and transport of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) across tailings with both depth and hill slopes is still unknown. In this study, the amount of NH4+-N and nitrate nitrogen (NO3−-N) was determined in tailings, and a soil column leaching experiment, served to assess the transport and distribution following mine closure. Firstly, a high concentration of NH4+-N in the leachate at the initial leaching stage was detected, up to 2000 mg L−1, and the concentration of NH4+-N clearly diminished as time passed. Meanwhile, the NH4+-N contents remained relatively high in soil. Secondly, both the content of NH4+-N and NO3−-N varied greatly according to vertical distribution after leaching lasting several years. The amounts of NH4+-N and NO3−-N in surface soil were much smaller than those in deep soil, with 3–4 orders of magnitude variation with depth. Thirdly, when disturbed by NH4+-N, the pH not only diminished but also changed irregularly as depth increased. Fourthly, although the amount of NO3−-N was smaller than that of NH4+-N, both their distribution trend was similar with depth. In fact, NH4+-N and NO3−-N were significantly correlated but this declined from the knap to the piedmont. Based on these results, it is suggested that mining activity could cause nitrogen to be dominated by NH4+-N and acidification in a tailing even if leaching occurs over several years. NO3−-N derived from NH4+-N transports easily and it becomes the main nitrogen pollutant with the potential to be a long-lasting threat to the environment around a mine.