Showing papers on "Nitrite published in 2019"
153 citations
TL;DR: In this paper, the state-of-the-art of carbon nanomaterial-enabled electrochemical sensors in nitrite detection in the past years (2014-2018) is presented.
Abstract: Nitrite is widely found in the natural environment and human life, but the abuse and potential toxicity of nitrite poses a great threat to human health. Therefore, it is necessary to develop effective, robust, and reliable methods for nitrite detection. Carbon nanomaterials have shown their great potential in the development of high-performance electrochemical sensors in view of their numerous fascinating properties. Carbon nanomaterial-enabled electrochemical sensors have been regarded as one of the most promising detection tools for nitrite due to their high sensitivity, simplicity of operation, and excellent selectivity. In this review, we introduce the state-of-art of carbon nanomaterial-enabled electrochemical sensors in nitrite detection in the past years (2014–2018). The properties and advantages of carbon nanotubes, graphene, graphene oxide, carbon nanofibers, carbon nanodots, nanodiamonds, and nanoporous carbon in the development of nitrite sensors are discussed in details. Furthermore, the challenges and prospects for the application of carbon nanomaterial-enabled electrochemical sensors for nitrite analysis are also included.
145 citations
TL;DR: In this paper, the performance of mono-and bimetallic surfaces for nitrite reduction can be rapidly screened using N, N2 and NH3 binding energies as reactivity descriptors.
Abstract: Nitrate (NO3–) is a ubiquitous contaminant in groundwater that causes serious public health issues around the world. Though various strategies are able to reduce NO3– to nitrite (NO2–), a rational catalyst design strategy for NO2– removal has not been found, in part because of the complicated reaction network of nitrate chemistry. In this study, we show, through catalytic modeling with density functional theory (DFT) calculations, that the performance of mono- and bimetallic surfaces for nitrite reduction can be rapidly screened using N, N2, and NH3 binding energies as reactivity descriptors. With a number of active surface atomic ensembles identified for nitrite reduction, we have designed a series of “metal-on-metal” bimetallics with optimized surface reactivity and a maximum number of active sites. Choosing Pd-on-Au nanoparticles (NPs) as candidate catalysts, both theory and experiment find that a thin monolayer of Pd-on-Au NPs (size: ∼4 nm) leads to high nitrite reduction performance, outperforming pu...
134 citations
TL;DR: In this article, an electrochemical sensing platform based on Cu-based metal-organic framework (Cu-MOF) decorated with gold nanoparticles (AuNPs) is constructed for the sensitive detection of nitrite.
Abstract: Herein, an electrochemical sensing platform based on Cu-based metal-organic framework (Cu-MOF) decorated with gold nanoparticles (AuNPs) is constructed for the sensitive detection of nitrite. Cu-MOF was synthesized by a simple wet chemical synthesis at room temperature. AuNPs were electrodeposited on Cu-MOF modified glass carbon electrode (Cu-MOF/GCE) using potentiostatic method. The AuNPs decorated Cu-MOF (Cu-MOF/Au) displays synergetic catalytic effect for the oxidation of nitrite due to the large surface area and porosity of Cu-MOF, which could prevent the aggregation of AuNPs and increase the adsorption of nitrite, combining with the high conductivity and excellent catalytic activity of AuNPs. A nitrite sensing platform was constructed based on Cu-MOF/Au/GCE, and amperometric technique was adopted for quantitative determination of nitrite. The prepared electrochemical sensing platform demonstrates high sensitivity, selectivity and good stability for the detection of nitrite. It shows two wide linear ranges of 0.1–4000 and 4000–10000 μM, and the low detection limit of 82 nM. Moreover, the sensing platform can also be used for the nitrite detection in real samples. This work would broaden the application of MOFs material in constructing more novel electrochemical sensing platforms.
132 citations
TL;DR: This study reports and demonstrates the first effective strategy to overcome NOB adaptation through alternating sludge treatment with free nitrous acid (FNA) and free ammonia (FA), and brings the mainstream nitrite shunt and PN/A one step closer to wide applications.
Abstract: Stable suppression of nitrite oxidizing bacteria (NOB) is one of the major bottlenecks for achieving mainstream nitrite shunt or partial nitritation/anammox (PN/A). It is increasingly experienced that NOB could develop resistance to suppressions over an extended time, leading to failure of nitrite shunt or PN/A. This study reports and demonstrates the first effective strategy to overcome NOB adaptation through alternating sludge treatment with free nitrous acid (FNA) and free ammonia (FA). During over 650 days of reactor operation, NOB adaptation to both FNA and FA was observed, but the adaptation was successfully overcome by deploying the alternate treatment strategy. Microbial community analysis showed Nitrospira and Nitrobacter, the key NOB populations in the reactor, have the ability to adapt to FNA and FA, respectively, but do not adapt to the alternation. Stable nitrite shunt with nitrite accumulation ratio over 95% and excellent nitrogen removal were maintained for the last 10 months with only one alternation applied. N2O emission increased initially as the attainment of nitrite shunt but exhibited a declining trend during the study. By using on-site-produced nitrite and ammonium, the proposed strategy is feasible and sustainable. This study brings the mainstream nitrite shunt and PN/A one step closer to wide applications.
131 citations
TL;DR: Analysis showed that the metabolic potential of the bacterial community for amino acids, nucleotides, coenzymes and inorganic ions decreased, while the relative abundance of key enzymes involved in nitrification and denitrification, and the relative population of denitrifying bacteria increased when the DO decreased.
120 citations
TL;DR: A novel process was proposed for achieving partial-denitrification/anammox in mainstream WWTPs by investigating the effect of pH on denitrification in three reactors with influent pH of 5.0, 7.0 and 9.0.
117 citations
TL;DR: In this article, a novel process was developed by combining endogenous partial denitrification (EPD, NO3−-N) with denitrifying phosphorus removal (DPR) in an anaerobic/anoxic/aerobic sequencing batch reactor (SBR) to achieve a stable nitrite accumulation and phosphorus removal from high-strength nitrate (NO3−N: 186.5
111 citations
TL;DR: When the aerobic tank of the A2O process of a pig farm wastewater treatment plant was inoculated with traditional activated sludge, the average removals of COD, NH4+- N and TN in the effluent were much lower, but the increase was statistically significant, indicating a great potential of strain T1 for full-scale applications.
110 citations
TL;DR: Strain LJ81 was isolated from domestic sludge, identified as Ochrobactrum anthropic, which was oxygen-dependent and could survive in a wide range of pH values and showed excellent performance on nitrogen removal without nitrite accumulation under aerobic condition.
109 citations
TL;DR: It is shown that an anammox bacterium can grow in the absence of nitrite by coupling ammonium oxidation to NO reduction, producing only N2.
Abstract: Nitric oxide (NO) has important functions in biology and atmospheric chemistry as a toxin, signaling molecule, ozone depleting agent and the precursor of the greenhouse gas nitrous oxide (N2O). Although NO is a potent oxidant, and was available on Earth earlier than oxygen, it is unclear whether NO can be used by microorganisms for growth. Anaerobic ammonium-oxidizing (anammox) bacteria couple nitrite reduction to ammonium oxidation with NO and hydrazine as intermediates, and produce N2 and nitrate. Here, we show that the anammox bacterium Kuenenia stuttgartiensis is able to grow in the absence of nitrite by coupling ammonium oxidation to NO reduction, and produce only N2. Under these growth conditions, the transcription of proteins necessary for NO generation is downregulated. Our work has potential implications in the control of N2O and NO emissions from natural and manmade ecosystems, where anammox bacteria contribute significantly to N2 release to the atmosphere. We hypothesize that microbial NO-dependent ammonium oxidation may have existed on early Earth. Anammox bacteria couple nitrite reduction to ammonium oxidation, with nitric oxide (NO) and hydrazine as intermediates, and produce N2 and nitrate. Here, Hu et al. show that an anammox bacterium can grow in the absence of nitrite by coupling ammonium oxidation to NO reduction, producing only N2.
TL;DR: The present work provides not only a general one-pot synthesis method for a variety of noble-transition metal dichalcogenides nanohybrids, but also an example of the fabrication of an electrochemical nitrite sensor using a Nanohybrid as an enhanced material, an approach that can easily be extended to other sensors.
TL;DR: It is suggested that exposure to nitrogenous compounds such as ammonia, nitrite, and nitrate can induce significant toxicity and alterations in the antioxidant responses of P. olivaceus.
TL;DR: The formation of NO from nitrate and nitrite via a reductive 'nitrate-nitrite-NO' pathway and resulting in vasodilation is now an established complementary route to traditional NOS-derived vasocilation as discussed by the authors.
Abstract: Inorganic nitrate (NO3 - ), nitrite (NO2 - ) and NO are nitrogenous species with a diverse and interconnected chemical biology. The formation of NO from nitrate and nitrite via a reductive 'nitrate-nitrite-NO' pathway and resulting in vasodilation is now an established complementary route to traditional NOS-derived vasodilation. Nitrate, found in our diet and abundant in mammalian tissues and circulation, is activated via reduction to nitrite predominantly by our commensal oral microbiome. The subsequent in vivo reduction of nitrite, a stable vascular reserve of NO, is facilitated by a number of haem-containing and molybdenum-cofactor proteins. NO generation from nitrite is enhanced during physiological and pathological hypoxia and in disease states involving ischaemia-reperfusion injury. As such, modulation of these NO vascular repositories via exogenously supplied nitrite and nitrate has been evaluated as a therapeutic approach in a number of diseases. Ultimately, the chemical biology of nitrate and nitrite is governed by local concentrations, reaction equilibrium constants, and the generation of transient intermediates, with kinetic rate constants modulated at differing physiological pH values and oxygen tensions. LINKED ARTICLES: This article is part of a themed section on Nitric Oxide 20 Years from the 1998 Nobel Prize. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.2/issuetoc.
TL;DR: A kinetic model indicated that reactive nitrogen species could be important to the phototransformation of trace organic contaminants when relatively high concentrations of nitrite are present (e.g., in surface waters receiving reverse osmosis concentrate from potable water reuse projects or in agricultural runoff).
Abstract: Under conditions typically encountered in the aquatic environment, the absorption of sunlight by nitrite and nitrate leads to the transformation of trace organic contaminants. In addition to the well understood mechanism through which hydroxyl radical (·OH) produced by nitrate and nitrite photolysis oxidizes contaminants, absorption of light also results in the formation of reactive nitrogen species that transform organic contaminants. To assess the importance of this process on the fate of trace organic contaminants, radical quenchers and transformation product analysis were used to discriminate among potential reaction pathways. For sulfamethoxazole, an antibiotic that is frequently detected in municipal wastewater effluent, nitrate and nitrite-sensitized photolysis pathways resulted in production of transformation products that were not detected during direct photolysis or reaction with ·OH. The reactivity of sulfamethoxazole with the reactive species produced when nitrite absorbed sunlight was affected by the presence of hydroxyl radical scavengers, indicating the likely involvement of nitrogen dioxide, which forms when nitrite reacts with hydroxyl radical. Reactive nitrogen species also reacted with emtricitabine, propranolol, and other trace organic contaminants commonly detected in wastewater effluent, indicating the potential importance of this process to the fate of other trace organic contaminants. A kinetic model indicated that reactive nitrogen species could be important to the phototransformation of trace organic contaminants when relatively high concentrations of nitrite are present (e.g., in surface waters receiving reverse osmosis concentrate from potable water reuse projects or in agricultural runoff).
TL;DR: The multiple nitrogen pollutants in the original contaminated system were gradually removed with the reaction predominantly produced harmless nitrogen gas, and the final product was harmless nitrogenGas.
TL;DR: In this article, a sensitive electrochemical sensor based on cobalt oxide decorated reduced graphene oxide and carbon nanotubes (Co3O4-rGO/CNTs) has been successfully fabricated towards nitrite detection.
TL;DR: In this article, the microbially mediated NO3−-reducing Fe(II) oxidation process (NRFO) plays a key role in Fe/N interactions under neutral-anoxic conditions.
TL;DR: It is shown that nitrate concentration is substantially greater in skeletal muscle than in blood and is elevated further by dietary nitrate ingestion in human volunteers, and the presence of sialin, a nitrate transporter, and xanthine oxidoreductase in human skeletal muscle indicates that muscle has the necessary apparatus for nitrate transport, storage and metabolism.
Abstract: Key points Nitric oxide (NO), a potent vasodilator and a regulator of many physiological processes, is produced in mammals both enzymatically and by reduction of nitrite and nitrate ions. We have previously reported that, in rodents, skeletal muscle serves as a nitrate reservoir, with nitrate levels greatly exceeding those in blood or other internal organs, and with nitrate being reduced to NO during exercise. In the current study, we show that nitrate concentration is substantially greater in skeletal muscle than in blood and is elevated further by dietary nitrate ingestion in human volunteers. We also show that high-intensity exercise results in a reduction in the skeletal muscle nitrate store following supplementation, likely as a consequence of its reduction to nitrite and NO. We also report the presence of sialin, a nitrate transporter, and xanthine oxidoreductase in human skeletal muscle, indicating that muscle has the necessary apparatus for nitrate transport, storage and metabolism. Abstract Rodent skeletal muscle contains a large store of nitrate that can be augmented by the consumption of dietary nitrate. This muscle nitrate reservoir has been found to be an important source of nitrite and nitric oxide (NO) via its reduction by tissue xanthine oxidoreductase. To explore if this pathway is also active in human skeletal muscle during exercise, and if it is sensitive to local nitrate availability, we assessed exercise-induced changes in muscle nitrate and nitrite concentrations in young healthy humans, under baseline conditions and following dietary nitrate consumption. We found that baseline nitrate and nitrite concentrations were far higher in muscle than in plasma (∼4-fold and ∼29-fold, respectively), and that the consumption of a single bolus of dietary nitrate (12.8 mmol) significantly elevated nitrate concentration in both plasma (∼19-fold) and muscle (∼5-fold). Consistent with these observations, and with previous suggestions of active muscle nitrate transport, we present western blot data to show significant expression of the active nitrate/nitrite transporter sialin in human skeletal muscle. Furthermore, we report an exercise-induced reduction in human muscle nitrate concentration (by ∼39%), but only in the presence of an increased muscle nitrate store. Our results indicate that human skeletal muscle nitrate stores are sensitive to dietary nitrate intake and may contribute to NO generation during exercise. Together, these findings suggest that skeletal muscle plays an important role in the transport, storage and metabolism of nitrate in humans.
TL;DR: The results of nitrifying bacteria activities and quantities detection demonstrated that although NOB activities in both reactors were effectively inhibited, a certain amount of NOB were remained in the control reactor and multiplied rapidly as the DO concentration increased, which might break down the partial nitrification.
TL;DR: Batch tests showed that AOB, anammox bacteria and n-DAMO microorganisms were indeed jointly responsible for the nitrogen removal, and this one-stage PNAM process can potentially be applied to treating high-strength wastewater, such as anaerobic sludge digestion liquor or landfill leachate.
TL;DR: In this review, the nitrate and nitrite contents of food products from different countries are displayed globally in order to reinterpret the risks/benefits of the authors' consumption quotations.
Abstract: Nitrate and nitrite ions are used as food additives to inhibit the growth of microorganisms in cured and processed meats. Vegetables contain significant quantities of nitrate and nitrite. Actually, the vast majority of consumed nitrate and nitrite comes from natural vegetables and fruits rather than food additives. For years, the cancer risks of these two ions have been discussed, since they potentially convert into the carcinogenic nitrosamines. However, recently, these two ions have been considered essential nutrients which promote nitric oxide production and consequently help cardiovascular health. It seems that the role of these two ions in our diet is important now from a different point of view. In this review, the nitrate and nitrite contents of food products from different countries are displayed globally in order to reinterpret the risks/benefits of our consumption quotations. This review article is based on Science Citation Index (SCI) articles reported between 2008 and 2018.
TL;DR: It was shown that a bacterial strain LPN080 isolated and screened from a shrimp culture pond can efficiently remove both ammonia nitrogen and nitrite and showed high biosafety toward shrimp Litopenaeus vannamei and has a potential economic value in aquaculture and even in wastewater treatment.
TL;DR: High-throughput sequencing results showed that microbial community structure differed between the surface and interior space of polyurethane foams carriers while the dominant population in the inner zone of carriers was Pseudoxanthomonas.
TL;DR: This study demonstrated that SO4•- could induce the activation of nitrite, an anion commonly present in the subsurface environment, leading to the formation of nitrophenolic byproducts, the first study reporting the nitration of NOM and formation of toxic nitrobenzoic byproducts during SO4--based oxidation.
Abstract: Sulfate radical (SO4•–)-based advanced oxidation is a viable in situ remediation technology for degrading organic contaminants in the subsurface. In this study, we demonstrated that SO4•– could induce the activation of nitrite, an anion commonly present in the subsurface environment, leading to the formation of nitrophenolic byproducts. Fourier-transform infrared spectroscope and 15N nuclear magnetic resonance analysis revealed that the inorganic nitrite was incorporated into natural organic matter (NOM) to form organic nitrogen upon SO4•– oxidation. Nitrophenolic byproducts, including 2-hydroxy-5-nitrobenzoic acid, 4-nitrophenol, and 2,4-dinitrophenol, were identified using high-resolution mass spectrometry in combination with a 15N labeling technique. Formation of nitrated byproducts was ascribed to the scavenging of SO4•– by nitrite, which not only generated the nitrating agent NO2• but also inhibited the degradation of organic compounds, making them more available to the reactions with NO2•. The pheno...
TL;DR: The present review focuses on a different approach as it aims to understand the effects of hydrogenotrophy, alkaline pH and high nitrate concentration on microbial denitrification.
Abstract: Bacterial respiration of nitrate is a natural process of nitrate reduction, which has been industrialized to treat anthropic nitrate pollution. This process, also known as “microbial denitrification”, is widely documented from the fundamental and engineering points of view for the enhancement of the removal of nitrate in wastewater. For this purpose, experiments are generally conducted with heterotrophic microbial metabolism, neutral pH and moderate nitrate concentrations (<50 mM). The present review focuses on a different approach as it aims to understand the effects of hydrogenotrophy, alkaline pH and high nitrate concentration on microbial denitrification. Hydrogen has a high energy content but its low solubility, 0.74 mM (1 atm, 30 °C), in aqueous medium limits its bioavailability, putting it at a kinetic disadvantage compared to more soluble organic compounds. For most bacteria, the optimal pH varies between 7.5 and 9.5. Outside this range, denitrification is slowed down and nitrite (NO2−) accumulates. Some alkaliphilic bacteria are able to express denitrifying activity at pH levels close to 12 thanks to specific adaptation and resistance mechanisms detailed in this manuscript, and some bacterial populations support nitrate concentrations in the range of several hundred mM to 1 M. A high concentration of nitrate generally leads to an accumulation of nitrite. Nitrite accumulation can inhibit bacterial activity and may be a cause of cell death.
TL;DR: The present novel GECT sensor could act as a desirable practical platform for highly sensitive detection of nitrite in the food and environmental fields and showed good anti-interference performance toward common interfering ions and stable performances.
TL;DR: Investigation of coriander essential oil revealed significant antioxidative and antimicrobial activity of CEO, and consequently its high potential of utilization in processing of cooked pork sausages with enhanced quality and shelf-life.
TL;DR: In this article, a screen-printed fluorine-doped tin oxide (FTO) electrode with activated jute carbon paste (AJCP) was used for amperometric detection of nitrite.
TL;DR: The nitrite-mediated photooxidation of vanillin (VL), a phenolic compound abundant in biomass burning emissions, was investigated under pH conditions relevant for atmospheric waters and it is revealed that nitrophenols are the major reaction products.
Abstract: Nitrite (NO2–) and its conjugate acid, nitrous acid (HNO2), have long been recognized as a ubiquitous atmospheric pollutant as well as an important photochemical source of hydroxyl radicals (·OH) a...