Showing papers on "Nitrite published in 2021"
TL;DR: In this paper, a comparison of various AOPs in terms of nitro-products formation mechanisms and the associated environmental issues is presented, where the sonochemical nitrogen fixation is a key mechanism for the formation of Nitro-compounds in ultrasound-based AOP.
139 citations
TL;DR: Overall, for the first time putting together the acquired knowledge about hydroxylamine and the nitrogen cycle over the years in a review, setting potential hypothesis and highlighting possible next steps for research are highlighted.
81 citations
79 citations
TL;DR: In this article, a laser-induced graphene (LIG) electrode patterned onto a flexible poly(imide) substrate and further modified by COOH functionalized multiwalled carbon nanotubes (f-MWCNT) and gold nanoparticles (AuNPs) films is presented.
69 citations
TL;DR: This manuscript reviews and discusses the chemistry, safety, and regulatory considerations in the use of nitrite and nitrate from natural origin for the preservation of meat products.
69 citations
TL;DR: The results suggest that P. mendocina X49 achieved efficient and simultaneous nitrification and denitrification ability under heterotrophic aerobic conditions.
66 citations
TL;DR: In this article, the carbon-layer-coated In2O3 porous tubes (C@In 2O3 PTs) were used to detect nitrite in industrial wastewater samples.
Abstract: Excessive uptake of nitrite has been proven to be harmful for human health and ecological systems, so it is vital to develop a reliable methodology for nitrite analysis. In this work, we have synthesized innovative carbon-layer-coated In2O3 porous tubes (C@In2O3 PTs) to electrochemically detect nitrite in industrial wastewater samples. C@In2O3 PTs were prepared through the thermal decomposition of metal organic frameworks (MOFs, MIL-68-In) based on the two-step synthetic processes. The obtained C@In2O3 PTs displayed obviously increased catalytic activity to the electrochemical oxidation of nitrite, which benefited from the enhanced surface area and electron transfer based on the porous and hollow structure, and the maximized synergistic effect due to the intimate contact between In2O3 core and carbon layer. Thus, the sensitive determination of nitrite with a detection limit of 0.08 μM was realized, which was promising for sensitive determination of nitrite in the environmental analysis and food industry.
58 citations
TL;DR: In this article, a Cu3P nanowire array supported on copper foam (Cu3P NA/CF) was used as an efficient electrocatalyst for nitrite-to-ammonium conversion in neutral media.
55 citations
TL;DR: The possibility that nitrate represents an essential storage form of NO is considered and the integrated function of the oral microbiome, circulation, and skeletal muscle in nitrate–nitrite–NO metabolism is discussed, as well as the practical relevance for health and performance.
Abstract: Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in myriad physiological processes, including the regulation of vascular tone, neurotransmission, mitochondrial respiration, and skeletal muscle contractile function. NO may be produced via the canonical NO synthase-catalyzed oxidation of l-arginine and also by the sequential reduction of nitrate to nitrite and then NO. The body's nitrate stores can be augmented by the ingestion of nitrate-rich foods (primarily green leafy vegetables). NO bioavailability is greatly enhanced by the activity of bacteria residing in the mouth, which reduce nitrate to nitrite, thereby increasing the concentration of circulating nitrite, which can be reduced further to NO in regions of low oxygen availability. Recent investigations have focused on promoting this nitrate-nitrite-NO pathway to positively affect indices of cardiovascular health and exercise tolerance. It has been reported that dietary nitrate supplementation with beetroot juice lowers blood pressure in hypertensive patients, and sodium nitrite supplementation improves vascular endothelial function and reduces the stiffening of large elastic arteries in older humans. Nitrate supplementation has also been shown to enhance skeletal muscle function and to improve exercise performance in some circumstances. Recently, it has been established that nitrate concentration in skeletal muscle is much higher than that in blood and that muscle nitrate stores are exquisitely sensitive to dietary nitrate supplementation and deprivation. In this review, we consider the possibility that nitrate represents an essential storage form of NO and discuss the integrated function of the oral microbiome, circulation, and skeletal muscle in nitrate-nitrite-NO metabolism, as well as the practical relevance for health and performance.
52 citations
TL;DR: In this paper, a hierarchical structure including the multiwalled carbon nanotube (MWCNT) as substrates, Co-based metal-organic framework (Co-MOF) and high-dispersed small Au nanoparticles (AuNPs) was designed.
51 citations
TL;DR: In this article, Ni nanosheet arrays with Ni vacancies (Ni-NSA-VNi) were demonstrated to exhibit outstanding electrocatalytic performances toward selective nitrite reduction to ammonia (faradaic efficiency: 88.9%; selectivity: 77.2%).
Abstract: The development of efficient electrocatalysts for nitrite reduction to ammonia, especially integrated with a value-added anodic reaction, is important. Herein, Ni nanosheet arrays with Ni vacancies (Ni-NSA-VNi) were demonstrated to exhibit outstanding electrocatalytic performances toward selective nitrite reduction to ammonia (faradaic efficiency: 88.9%; selectivity: 77.2%) and semi-dehydrogenation of tetrahydroisoquinolines (faradaic efficiency: 95.5%; selectivity: 98.0%). The origin and quantitative analyses of ammonia were performed by 15N isotope labeling and 1H NMR experiments. The decrease in electronic cloud density induced by the Ni vacancies was found to improve the NO2− adsorption and NH3 desorption, leading to high nitrite-to-ammonia performance. In situ Raman results revealed the formation of NiII/NiIII active species for anodic semi-dehydrogenation of tetrahydroisoquinolines on Ni-NSA-VNi. Importantly, a Ni-NSA-VNi‖Ni-NSA-VNi bifunctional two-electrode electrolyzer was constructed to simultaneously produce ammonia and dihydroisoquinoline with robust stability and high selectivity.
TL;DR: In this article, a denitrifying polyphosphate accumulating organisms (DPAO) was used as an electron acceptor in a sequencing batch reactor (SBR) at a nitrate dosing rate of 20-25 mg N L-1 d-1.
TL;DR: The results of pH, colour, lipid oxidation, nitrite and nitrate analysis suggest R1 treatment as a potential nitrite replacer obtained from a simple and feasible drying process.
TL;DR: Nitrite incorporated films were demonstrated as efficient active packaging to improve the quality of red meat products and inhibited growth of lactic acid bacteria, yeast and mold, and retained softer texture during storage.
TL;DR: In this article, an RM reactor with the fixed 1-Amino-4-hydroxyanthraquinone (AHAQ) and three core strains was established and achieved high nitrate removal efficiency (NRE) under low carbon to nitrogen ratio (C/N) and short hydraulic retention time (HRT) conditions, with the maximum efficiency of 99.41% (14.00 mg L−1 h−1
TL;DR: In this paper, the inhibitory performance and mechanism of compound nitrite with D-sodium gluconate on carbon steel in simulated concrete pore solution was studied, and results of EIS, SEM and AFM indicate that the pitting corrosion of the steel was effective hindered by corrosion inhibitor in the pore solutions.
TL;DR: In this article, a robust nitritation process was demonstrated in treating low-strength wastewater, obtained from a mixture of real mainstream sewage with sidestream anaerobic digestion liquor.
Abstract: Oxidation of ammonium to nitrite rather than nitrate, i.e., nitritation, is critical for autotrophic nitrogen removal. This study demonstrates a robust nitritation process in treating low-strength wastewater, obtained from a mixture of real mainstream sewage with sidestream anaerobic digestion liquor. This is achieved through cultivating acid-tolerant ammonia-oxidizing bacteria (AOB) in a laboratory nitrifying bioreactor at pH 4.5-5.0. It was shown that nitrite accumulation with a high NO2-/(NO2- + NO3-) ratio of 95 ± 5% was stably maintained for more than 300 days, and the obtained volumetric NH4+ removal rate (i.e., 188 ± 14 mg N L-1 d-1) was practically useful. 16S rRNA gene sequencing analyses indicated the dominance of new AOB, "Candidatus Nitrosoglobus," in the nitrifying guild (i.e., 1.90 ± 0.08% in the total community), with the disappearance of typical activated sludge nitrifying microorganisms, including Nitrosomonas, Nitrospira, and Nitrobacter. This is the first identification of Ca. Nitrosoglobus as key ammonia oxidizers in a wastewater treatment system. It was found that Ca. Nitrosoglobus can tolerate low pH (<5.0), and free nitrous acid (FNA) at levels that inhibit AOB and nitrite-oxidizing bacteria (NOB) commonly found in wastewater treatment processes. The in situ inhibition of NOB leads to accumulation of nitrite (NO2-), which along with protons (H+) also produced in ammonium oxidation generates and sustains FNA at 3.0 ± 1.4 mg HNO2-N L-1. As such, robust PN was achieved under acidic conditions, with a complete absence of NOB. Compared to previous nitritation systems, this acidic nitritation process is featured by a higher nitric oxide (NO) but a lower nitrous oxide (N2O) emission level, with the emission factors estimated at 1.57 ± 0.08 and 0.57 ± 0.03%, respectively, of influent ammonium nitrogen load.
TL;DR: This work demonstrated n-DAMO archaea coupling the anaerobic oxidation of methane to DNRA, which fueled Anammox in a methane-fed membrane biofilm reactor with nitrate as only electron acceptor, and produced ammonium from nitrate rather than from external nitrite.
Abstract: Nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) is critical for mitigating methane emission and returning reactive nitrogen to the atmosphere. The genomes of n-DAMO archaea show that they have the potential to couple anaerobic oxidation of methane to dissimilatory nitrate reduction to ammonium (DNRA). However, physiological details of DNRA for n-DAMO archaea were not reported yet. This work demonstrated n-DAMO archaea coupling the anaerobic oxidation of methane to DNRA, which fueled Anammox in a methane-fed membrane biofilm reactor with nitrate as only electron acceptor. Microelectrode analysis revealed that ammonium accumulated where nitrite built up in the biofilm. Ammonium production and significant upregulation of gene expression for DNRA were detected in suspended n-DAMO culture with nitrite exposure, indicating that nitrite triggered DNRA by n-DAMO archaea. 15N-labeling batch experiments revealed that n-DAMO archaea produced ammonium from nitrate rather than from external nitrite. Localized gradients of nitrite produced by n-DAMO archaea in biofilms induced ammonium production via the DNRA process, which promoted nitrite consumption by Anammox bacteria and in turn helped n-DAMO archaea resist stress from nitrite. As biofilms predominate in various ecosystems, anaerobic oxidation of methane coupled with DNRA could be an important link between the global carbon and nitrogen cycles that should be investigated in future research.
TL;DR: Results suggest both ionic stress and ion composition contributed to the observed inhibition of Anammox bacteria in wastewater with elevated salt content.
TL;DR: Results revealed that through regulating chemical oxygen demand to phosphate ratio, Candidatus_Competibacter was highly enriched in EPDA and EPDG, resulting high intracellular carbon storage efficiencies, and with whether acetate or glucose, the EPD-AMX processes could achieve the same level of total nitrogen removal efficiencies.
TL;DR: This study developed a novel strategy for rapidly achieving partial nitrification (PN) without additional chemical agents, and infrastructure costs, only by controlling aeration time to selectively enrich ammonium oxidizing bacteria (AOB) after simultaneously eliminating AOB and nitrite oxidizingacteria (NOB).
TL;DR: In this paper, the authors investigated the feasibility of Alcaligenes faecalis strain WT14 in nitrogen removal in a constructed wetland, and the results showed that WT14 was more readily utilized by WT14 as a carbon source.
TL;DR: The results of this study provide support for the establishment of a high-rate BNR system that maintains its stability with a low sludge yield.
TL;DR: A mixed culture was acclimated to deal with simultaneous nitrification-denitrification coupled to methane oxidation in a laboratory-scale hollow-fiber membrane biofilm reactor, which achieved a steady ammonia removal rate and indicated that the coupling of nitrate/nitrite denitrification and methane oxidation was beneficial.
TL;DR: The use of biologically produced nitrate/nitrite by nitrification of two different ammonium substrates, namely synthetic medium and landfill leachate, is proposed as a novel alternative and the results demonstrate the feasibility of using both ammonia substrates as nutrient solutions.
TL;DR: In this paper, the process of autotrophic denitrification driven by sulfide as an electron donor was investigated in a sequencing batch reactor, and the results showed that the removal rates of NO3-N and S2-S were 95.8% and 100%, respectively, when the S/N molar ratio was 1.45.
TL;DR: In this article, a new pretreatment method to enhance anaerobic digestion was achieved by treating thickened WAS (TWAS) with ferric (as FeCl3) and nitrite simultaneously for 24-hour at room temperature.
TL;DR: Investigation of the preferential use of the nitrogen oxides involved in denitrification and nitrous oxide accumulation in two enrichments of Accumulibacter and a competitor indicates that DPAOs can contribute to lowering N2O emissions in the presence of multiple electron acceptors under partial nitritation conditions.
TL;DR: A mini-review of fungal denitrification and other nitrate/nitrite reduction processes is overviewed, to discuss their environmental impacts, summarize recent advancements in the methods to study fungal Denitrification, and provide insights on future research opportunities.
Abstract: Fungi play a key role in the nitrogen cycle. Diverse fungi are known to reduce nitrate or nitrite to gaseous nitrogen oxides such as nitric oxide, nitrous oxide (N2O), and dinitrogen via denitrification or co-denitrification (microbially mediated nitrosation), and to ammonium via ammonia fermentation (fungal dissimilatory nitrate reduction to ammonium). These processes could significantly contribute to the emission of N2O from soils and the removal of nitrogen from nitrate and nitrite-contaminated environments. However, fungal N2O production may not be necessarily related to their denitrification activity sensu stricto (i.e., reduction of nitrate or nitrite to gaseous N oxides for respiration): N2O can be produced by partially abiotic processes. Therefore, fungi that can reduce nitrate or nitrite to N2O should not be called denitrifying fungi instantaneously. Experiments should be carefully conducted to better discriminate fungal denitrification, co-denitrification, and chemo-denitrification. Various analytical tools have been developed and applied to clarify fungal denitrification and other nitrate/nitrite reduction processes, including the substrate-induced respiration-inhibition method, stable isotope analyses, and culture-dependent and -independent molecular and genomic approaches. In this mini-review, we overview fungal denitrification and other nitrate/nitrite reduction processes, discuss their environmental impacts, summarize recent advancements in the methods to study fungal denitrification, and provide insights on future research opportunities.
TL;DR: This work first proposed the application of a facile dual-function fluorescent probe 2-(1H-Benzimidazol-2-yl)Aniline (BMA) for the detection of phosgene and nitrite in different solvent environments and showed good responses.