90 results about "Nitrite" patented technology

The invention relates to the technical field of biological denitrification, in particular to a nitrogen-doped carbon dot-based microbial electronic control denitrification system and application thereof. The system comprises electron donor microorganisms, electron acceptor microorganisms and nitrogen-doped carbon dots, the nitrogen-doped carbon dots serve as electron mediators outside cells, an efficient extracellular electron transfer network is constructed, and interspecific electron transfer resistance is reduced; meanwhile, the nitrogen-doped carbon dots can regulate and control intracellular electron transport chains and the energy metabolism process, the improvement of the reducing power and the energy level is promoted, and the metabolism mode optimization is realized. By cooperatively regulating and controlling generation, transmission and utilization of electrons under an extreme electron donor limited oligotrophic condition, the system disclosed by the invention can realize efficient denitrification, avoid nitrite accumulation, remarkably inhibit generation of nitrous oxide (N2O), reduce dependence on an external organic carbon source and an electron source, and improve the denitrification efficiency. And a new technical approach is provided for improving the deep denitrification efficiency under the low-carbon condition.

The invention relates to the technical field of electro-catalysis, in particular to a metal monatomic doped copper-based catalyst and a preparation method and application thereof. The metal single atoms in the catalyst are selected from palladium single atoms, iron single atoms, nickel single atoms or ruthenium single atoms; the doping amount of the metal single atoms is 0.5%-1.0% on the basis of the total mass of the catalyst. The invention provides a novel metal monatomic doped copper-based catalyst, which can be used for catalyzing the reduction of a harmful substance nitrite into a chemical ammonia with an economic added value by using renewable electric power, can solve the problems of nitrite pollution and environment and energy caused by ammonia production by a Have-Bosch method, and realizes the purpose of turning waste into wealth.

The application belongs to the technical field of electrocatalysis, and discloses a bimetallic fluorinated metal organic framework catalyst, a preparation method thereof and application of the catalyst in active oxygen assisted membrane-free electrolytic ammonia oxidation for preparing nitrite, wherein the catalyst is prepared by self-assembly of Cu 2+ , Ni 2+ and a tetrakisfluorophthalic acid ligand through a solvothermal method, and there is a directional electron transfer effect between Cu and Ni. The application utilizes the Cu / Ni bimetallic electron synergistic effect to precisely regulate the d-band center of the catalyst, and a membrane-free electrolysis device is matched to save an expensive proton exchange membrane. The application provides a new efficient and feasible path for green, economical and scaled electrocatalytic synthesis of nitrite.

This invention belongs to the field of electrochemical sensor technology for water quality analysis, specifically relating to an integrated sensor for rapid on-site self-separation detection of nitrite in complex seawater. It includes a self-separating membrane, a membrane slot, a screen-printed electrode, and an electrode slot. Two self-separating membranes fixed in the membrane slots and the screen-printed electrode fixed in the electrode slots are connected sequentially in a vertical direction, which is the sample flow direction. The screen-printed electrode is modified with ZnS / VMSF-TMAC material to form a sensing interface with anion-selective permeability. A filtrate storage cavity is formed between the self-separating membrane and the screen-printed electrode to store the filtrate to be tested after filtration through the self-separating membrane. This sensor, when used in complex seawater environments, has a detection range of 0.005-5 mM and retains 85% of the signal after 28 days of storage.

The invention relates to a surface modified Fe / Cu-Co3O4 catalyst for nitrite detection and a preparation method thereof, a sensor and application, and the preparation method comprises the following steps: dissolving a cobalt source, an iron source, a copper source, urea and NH4F in deionized water, carrying out a hydrothermal reaction, washing, drying and calcining to obtain a Fe and Cu co-doped Co3O4 nanotube; and pre-hydrolyzing by using a KH792 silane coupling agent ethanol-water solution, and reacting with nanotubes to prepare the surface modified catalyst. The sensor takes carbon cloth or a screen-printed electrode subjected to ultrasonic cleaning and plasma treatment as a substrate, catalyst ink is coated to form a catalytic layer, and the catalytic layer, a platinum counter electrode and a silver / silver chloride reference electrode form a three-electrode system. Through molecular modification and material design, the interfacial force between the catalyst and nitrite is improved, the electrode stability is enhanced, and the catalyst is applied to a disposable printed electrode and portable detection equipment, so that high-sensitivity, stable and portable detection of nitrite is realized.

This utility model discloses an aerobic mixed liquor nitrification and deoxygenation treatment device, including a first nitrification tank. A nitrite-containing bacteria storage tank is located at the top of the first nitrification tank. An inlet pipe is located at the top of one side of the first nitrification tank, and one side of the inlet pipe extends into the interior of the first nitrification tank and is equipped with a sludge-water separation chamber. Through the cooperation of the inlet pipe, sludge discharge pipe, screen, and sludge-water separation chamber, this utility model can separate the sludge mixed in with the mixed liquor during its inflow, while also facilitating the return of the sludge to the treatment tank. Then, through the cooperation of a second discharge pipe, a third pump, a pump installation chamber, a distribution plate, a distribution pipe, a heat dissipation chamber, and a fan, the mixed liquor can be continuously circulated and cooled during the nitrification reaction, thereby maintaining the mixed liquor at 20-30°C to preserve the activity of nitrite-containing bacteria and nitrifying bacteria in the mixed liquor and ensure reaction efficiency.

The present invention relates to systems and methods for catalytic removal of oxidized contaminants (for example, nitrite, chromate, chlorate, trichloroethene, CFC-11, 4-nonylphenol, RDX, and perfluorooctanoate) from water and wastewater. In some aspects, the catalytic method of removing oxidized contaminants comprises using precious metal nanoparticles as catalysts to reduce the oxidized contaminants.

This invention discloses a GSH-functionalized carbon dots / rhodamine B ratiometric fluorescence system, its construction method, and its application in nitrite detection. GSH-CDs are synthesized via a one-step hydrothermal method by mixing citric acid, o-phenylenediamine, glutathione, and hydrochloric acid in water. Unreacted precursors and small molecules are removed by purification, and the GSH-CDs are obtained by freeze-drying. The ratiometric fluorescence system is constructed by mixing rhodamine B, GSH-CDs, and an acidic buffer solution. The fluorescence intensity ratio F of GSH-CDs to rhodamine B is established. 460 / F 590 With nitrite (NO2) ‑ A calibration curve between concentrations was obtained, and the NO2 in the actual sample was experimentally detected using the spiked recovery method. ‑ Content. Under acidic conditions, with NO2... ‑ With increasing concentration, the GSH-CDs / RhB fluorescence intensity ratio (I 460 / I 590 Significant changes occurred, with the fluorescence intensity ratio compared to NO2. ‑ There is a good linear relationship between concentrations. Compared with the detection platform based on GSH-CDs, the ratio fluorescence system provided by this invention has a lower detection limit and significantly higher sensitivity.

A polymer comprising pyridinium salt moieties, wherein the polymer has the following structure: In this structure, R1 and R6 are each N. At least a portion of R2 and R7 groups in the polymer are each negatively charged counterions selected from the group consisting of carboxylates, nitrates, nitrites, azides, metasilicates, tetraborate, perborates, boronates, oxalatob orates, metaborates, phosphorus-containing anions, halides, sulfates, SO4 -2, HSO4 -1, thiosulfate, dithionite, metabisulfite, persulfate, methanesulfonate, dioctyl sulfosuccinate, 3-sulfopropyl ethoxylate laurylphenyl ether, and combinations thereof. R3, R4, R8, R9, R11, R13, R14, R15, and R16 are each selected from the group consisting of H and groups including one or more carbon atoms. R5 and R10 are any group including one or more carbon atoms. The n is an integer from 2 to about 100,000.

A method of fabricating a plant-based additive for inhibiting nitrite formation during meat preparation includes reacting a pomegranate peel extract with a zinc precursor solution to obtain a reaction mixture, stirring the reaction mixture for 15 to 60 min at a temperature of 50 to 90° C. to obtain zinc oxide nanoparticles; and combining the zinc oxide nanoparticles with at least one extract selected from the group consisting of red cabbage extract and a beet root extract to obtain the plant-based additive. The extract comprises 500 to 1000 parts per million of nitrate relative to a total weight of the plant-based additive.

The invention discloses a method for detecting nitrite in a metronidazole bulk drug. According to the method, an ultraviolet spectrophotometric method is adopted, diazotization with sulfanilamide is carried out, then color development with N-(1-naphthyl) ethylenediamine hydrochloride is carried out, and the content of nitrite is detected at the wavelength of 530-534 nm. According to the detection method, the content of nitrite in the metronidazole bulk drug can be rapidly and accurately detected, and the method is high in recovery rate and sensitivity and good in precision, repeatability and linearity.

The invention discloses a preparation method and application of a nano manganese oxide compound, and the preparation method comprises the following steps: dissolving an amino siloxane compound in water containing dissolved oxygen to obtain 8lt; an aqueous solution of an aminosiloxane compound having a pH < = 12; adding a Mn < 2 + > solution into the amino siloxane compound aqueous solution, and reacting at room temperature; and after the reaction is performed for preset time, adding acid to terminate the reaction to obtain a nano manganese oxide dispersion liquid, and centrifugally washing to obtain the nano manganese oxide. The preparation method is mild in reaction condition, the nano manganese oxide can be rapidly prepared, the obtained nano manganese oxide has oxidase-like catalytic activity, and a nitrite detection system constructed based on the nano manganese oxide has the characteristics of low detection limit, high sensitivity, strong anti-interference performance, good selectivity and the like.

This invention relates to the field of biological denitrification technology, and more particularly to a microbial electron-regulated denitrification system based on nitrogen-doped carbon dots and its application. The system comprises electron-donating microorganisms, electron-accepting microorganisms, and nitrogen-doped carbon dots. The nitrogen-doped carbon dots act as extracellular electron mediators, constructing an efficient extracellular electron transport network and reducing interspecies electron transport resistance. Simultaneously, the nitrogen-doped carbon dots can regulate intracellular electron transport chains and energy metabolism processes, promoting increased reducing power and energy levels, and optimizing metabolic patterns. By synergistically regulating electron generation, transport, and utilization under oligotrophic conditions with limited electron donors, this system achieves highly efficient denitrification, avoids nitrite accumulation, and significantly inhibits nitrous oxide (N2O) generation, while reducing dependence on external organic carbon sources and electron sources. This provides a new technical approach for improving the efficiency of deep denitrification under low-carbon conditions.

The invention provides a preparation method of 2-bromine-5-fluorobenzotrifluoride and a preparation method of the 2-bromine-5-fluorobenzotrifluoride. Specifically, the invention provides a preparation method of a compound as shown in a formula E. The preparation method comprises the following steps: reacting a compound as shown in a formula A with urea to generate a compound as shown in a formula B; in an organic solvent, carrying out substitution reaction on the compound as shown in the formula B and bromine to generate a compound as shown in a formula C; carrying out hydrolysis reaction on the compound as shown in the formula C in an alkaline solution to generate a compound as shown in a formula D; and carrying out diazotization reaction on the compound shown in the formula D, HF and nitrite to generate a compound shown in a formula E. According to the preparation method, the reaction steps are simplified, the bromination selectivity is high, and the production cost can be effectively reduced.

The invention develops an axial weak coordination synthesis method for regulating and controlling a cobalt phthalocyanine molecular metal d band center based on a graphdiyne topological structure. The method is characterized in that a series of graphdiyne two-dimensional interfaces with different topological structures are obtained by regulating and controlling the arrangement and proportion of sp-and sp-hybridized carbon atoms, and the adsorption configuration of cobalt phthalocyanine molecules along the graphdiyne topological structure two-dimensional interfaces is regulated by utilizing the d-pi action between sp-carbon and a cobalt metal center. The weak coordination regulation effect of sp-carbon on the d band center of cobalt phthalocyanine metal is realized. In the process of preparing hydroxylamine from nitrate through electro-catalysis, the adsorption energy of hydroxylamine at the Co-N4 site is reduced through the axial weak coordination effect of sp-carbon; sp-carbon can be used as a transfer station for catalyzing nitrate to nitrite to assist the nitrite to be reduced into hydroxylamine at the cobalt phthalocyanine Co-N4 site, so that a full-chain series catalytic mechanism is formed.

The application discloses an oxygen-enriched vacancy CeOx@Cu catalyst, a preparation method thereof and application of the catalyst in nitrate reduction, and belongs to the technical field of electrochemical catalytic materials and preparation thereof. The application solves the problems of slow kinetics of conversion of nitrite into ammonia and insufficient supply of active hydrogen species in the existing electrochemical reduction process of nitrate in water. In the application, CeO2 nanoparticles are uniformly loaded on a copper substrate by an electrodeposition method, and a composite catalyst CeOx@Cu with high-density oxygen vacancies is formed through calcination treatment, overflow of oxygen vacancy-mediated *H from CeOx to the copper surface significantly accelerates the reduction kinetics of nitrate, and side reactions are inhibited, thereby excellent ammonia generation performance (404.08 mu mol h ‑1 cm ‑2 ) and high Faraday efficiency (FE reaches 94.6%) are exhibited, and nitrate in wastewater can be effectively converted into ammonia, and electric energy can be recovered.

The present invention relates to a method for treating an effluent from a nitriding line by membrane electrodialysis, the method comprising the application of an electric voltage between the anode and the cathode of an electrodialysis device for separating alkali metal cations and anionic species selected from nitrates, hydroxides, nitrites, carbonates and mixtures thereof.

The invention provides a nitrite quantitative detection method based on surface enhanced Raman spectroscopy, relates to the technical field of surface enhanced Raman spectroscopy, and constructs a self-correcting SERS substrate through a three-phase liquid-liquid interface co-assembly technology. In the experiment process, a sample to be detected is mixed with a thiobarbituric acid solution, the mixture is adjusted to be acidic, NO2 <-> and thiobarbituric acid are subjected to an S-nitrosation reaction, and S-nitroso mercaptan is generated. And then, immersing the self-correcting SERS substrate into a reaction solution, so that the substrate adsorbs the generated S-nitroso mercaptan, and further, a Raman signal is enhanced. After soaking is completed, the substrate is taken out and dried, finally, a Raman signal is collected through a Raman spectrometer, and the concentration of NO2 <-> is accurately analyzed through the change of the signal intensity. According to the technical scheme, rapid and high-sensitivity detection of NO2 <-> is achieved, good selectivity and anti-interference capacity are achieved, and the method is widely suitable for detection requirements of multiple fields such as environment monitoring and food safety.

The invention discloses a preparation method of 4-bromophenylhydrazine hydrochloride, and relates to the technical field of organic synthesis, and the preparation method comprises the following steps: S1, diazotization: mixing 4-bromoaniline and concentrated hydrochloric acid, adding a sodium nitrite aqueous solution under a stirring condition, and reacting to obtain a reaction solution; step S2, reduction: adding concentrated hydrochloric acid and ammonium sulfite into the reaction liquid obtained in the step S1, reacting, separating out crystals, and filtering; s3, salifying: dissolving a product obtained after filtering in the step S2 in concentrated hydrochloric acid, stirring at 80-85 DEG C until crystals are separated out, and performing suction filtration and drying to obtain 4-bromophenylhydrazine hydrochloride; in the diazotization process in the step S1, the speed of adding the sodium nitrite aqueous solution is controlled to be 70-85 mL / min in the stirring process. By controlling the adding speed of the sodium nitrite, the speed of the sodium nitrite aqueous solution is controlled to be 70-85 mL / min, so that the diazonium salt decomposition caused by high sodium nitrite adding speed and excessive nitrous acid in the reaction is avoided, and meanwhile, the diazotization reaction time can be reasonably shortened.

The application discloses a preparation method and application of a nitrite electrochemical sensor based on a polydopamine nanosphere composite material, and belongs to the fields of functional nanocomposite materials and sensing technologies. The prepared polydopamine nanospheres are ultrasonically treated in a hexadecyltrimethylammonium bromide solution, a polydopamine nanosphere / hexadecyltrimethylammonium bromide composite is obtained through electrostatic action, and the composite is drop-coated on a clean electrode surface, and is dried at room temperature to obtain an electrochemical sensor, which can be applied to the detection of nitrite in cured meat. The nanomaterial composite material is simple to prepare and low in cost, and the prepared nitrite electrochemical sensor has high sensitivity, a low detection limit, a wide detection range, a fast detection speed and good reproducibility.

The invention relates to the technical field of functional materials and synthesis thereof, in particular to a monodisperse ruthenium-based composite photo-thermal catalytic material and a preparation method thereof. Comprising the following steps: mixing and stirring Al (NO3) 39H2O, CO (NH2) 2 and deionized water, then carrying out hydrothermal reaction, cooling, filtering, washing, drying, calcining and grinding to obtain Al2O3 powder; the preparation method comprises the following steps: adding Al2O3 powder into deionized water, then adding a ruthenium nitrosyl nitrate solution, grinding, evaporating to dryness, reducing, and collecting a sample Rux / Al2O3 to obtain the monodisperse ruthenium-based composite photo-thermal catalytic material. The preparation method disclosed by the invention is simple, and the problem that the catalyst is inactivated due to low reforming performance and carbon deposition of a photo-thermal catalytic CH4-CO2 dry method is solved.

The invention relates to the technical field of aquaculture water treatment technologies, and discloses an electrolytic advanced oxidation aquaculture circulating water purification treatment system which comprises a pretreatment unit, an advanced oxidation catalysis unit and a water quality optimization unit which are sequentially communicated through pipelines, and further comprises an electrolytic preparation unit for providing raw materials for the advanced oxidation catalysis unit, the system takes electrolyzed water as a core, oxygen, hydrogen, ozone and hydrogen peroxide are self-produced in the system, self-sufficiency of chemicals is realized, and the operation cost and the storage and transportation risk are reduced. The advanced oxidation unit efficiently degrades organic matters, ammonia nitrogen and nitrite and thoroughly inactivates pathogens by utilizing self-produced ozone and hydrogen peroxide and combining ultraviolet catalysis. The system process follows the grading load principle of physical interception, chemical oxidation and water quality optimization, no residual oxidizing agent is ensured through second UV catalysis, electrolytic gas separation effectively prevents explosion, and safe, efficient and healthy circulating aquaculture is integrally achieved.

The invention relates to the field of materials, and discloses a surface wave-shaped gold nanocrystalline material and a preparation method and application thereof.The preparation method comprises the steps that a chloroauric acid solution A1, a sodium hydroxide solution B1 and a solution C1 containing a first ligand react to obtain a first solution; the first ligand is selected from more than one of nitrite, citrate, sulfite and hypophosphite; a solution 1 containing a second ligand, a solution 2 containing a nanocrystalline template and a reducing agent solution 3 are mixed to obtain a mixed solution 4, the solution I is added into the mixed solution 4 to obtain a solution II, and the second ligand is selected from one or more of polyvinylpyrrolidone and poly (diallyldimethylammonium chloride) heat exchange sodium dodecyl benzene sulfonate; and mediating a mediating agent into the solution II to obtain the gold nanocrystalline material with the wavy surface. According to the method, the gold nanocrystals are synthesized in a water phase at normal temperature and normal pressure by adopting a wet chemical method, the surfaces of the prepared gold nanocrystals are wavy, and the roughness is continuously adjustable.

Processes for making steel products. In some embodiments, the process can include passing a heated steel billet through a rolling mill to form the steel billet into the steel product. The steel product can be at a temperature of at least 800°C upon exiting the rolling mill. The process can also include contacting the steel product with a quench medium to produce a quenched steel product. The quenched steel product can be at a temperature in a range from about 300°C to about 500°C. The process can also include cooling the quenched steel product to ambient temperature to produce a final steel product. An azole compound can be applied to the steel product during contact with the quench medium, applied to the quenched steel product, or a combination thereof and / or a nitrite compound can be applied to the quenched steel product.

The present application relates to a natural coloring agent composition including a fermented plant product, wherein the composition includes nitrite in a concentration of 700 ppm or more and includes free sugar in a concentration of 1,000 ppm or less, and the free sugar includes lactose. The natural coloring agent composition may be prepared from natural raw materials to contain nitrite in a high concentration without inoculation of reducing bacteria, and may have an excellent color development effect when applied to meat products in place of synthetic nitrite.

An oxidative bioleaching process for leaching a base metal from an ore that includes an ore agglomeration step, an ore stacking step wherein agglomerated ore is stacked to form a heap, a curing step, a rinse step, an inoculation step and a leach step, and wherein, during the ore agglomeration step, the ore is contacted with an acid solution containing nitrate or nitrite thereby to accelerate the leaching rate in the leach step.

A method for extracting copper from sulphide mineral ore, comprising the following steps: stacking the ore to form a pile (heap), a leaching step, irrigating the pile with a first irrigating solution containing an acidic nitrate solution and nitrite, thereby causing the oxidation of sulfide minerals inside the pile, oxidation of gaseous nitrogen oxide released during the oxidation of sulfide minerals inside the pile with oxygen to form nitrogen dioxide, and hydrolysis of nitrogen dioxide to form nitric acid and / or nitrous acid in the first irrigating solution inside the pile, to continue the leaching stage and reduce nitrogen oxide losses from the pile.

To provide an inexpensive method for detecting nitrites that can reliably detect them. [Solution] A method for detecting nitrites, comprising: a first step of reacting a liquid sample with indole under hydrochloric acid conditions; and a second step of measuring the absorbance of the compound obtained in the first step in a wavelength range of 470 nm to 510 nm.

Methods and compositions for inhibiting corrosion in closed loop systems in which a heat transfer fluid is recirculated. A combination of a C6-C14 dicarboxylic acid and C6-C14 monocarboxylic acid is added to the recirculating fluid in a weight ratio of from 10:1 to 1:2.

The application belongs to the technical field of soil treatment and sewage treatment, and particularly relates to application of 5-methylisoxazole nitrification inhibitor and a method for inhibiting nitrification. The application comprises application in inhibiting nitrification activity of ammonia-oxidizing bacteria and in inhibiting nitrification activity of nitrite-oxidizing bacteria. Through a large number of researches and experiments, the application finds nitrification inhibition activity of 5-methylisoxazole, and realizes full-path regulation of nitrification. Experiments show that the compound can inhibit ammonia oxidation activity of a typical nitrifying strain at a low dose (>=0.01‰w / v), and can effectively inhibit activity of nitrite-oxidizing bacteria at a concentration lower than 0.1‰m / v. The aqueous solution of the compound has a neutral pH, and has no significant inhibitory effect on non-target heterotrophic microorganisms, and has high selectivity and environmental friendliness.