543 results about "Nitrate" patented technology

The invention belongs to the field of biochar adsorbing materials, and relates to a method for preparing modified biochar with aquatic plant waste and hematite. The method includes the following steps: (1) naturally drying aquatic plants prior to crushing to obtain aquatic plant powder; (2) crushing the hematite to obtain hematite powder; (3) weighing the hematite powder prior to putting the hematite powder into deionized water, and performing ultrasonic treatment to obtain suspension; (4) weighing the aquatic plant powder, soaking the aquatic plant powder in the suspension, and stirring and drying to obtain fully mixed aquatic plant and hematite mixture; (5) weighing the fully mixed aquatic plant and hematite mixture, putting the mixture in a batch-type atmosphere furnace, and feeding nitrogen into the furnace; performing temperature programming to the target temperature, and maintaining final-temperature pyrolysis; after the pyrolysis process is finished, obtaining the target product, namely the modified biochar. The modified biochar has strong adsorbability in nitrate and phosphate, high in stability and reusable.

A fire retarding biochemical liquid composition including: a dispersing agent realized in the form of a major amount of water, for dispersing alkali metal ions dissolved in the water; a major amount of a first fire retarding agent realized in the form of a first alkali metal salt of a nonpolymeric saturated carboxylic acid, specifically, tripotassium citrate, for providing metal potassium ions dispersed in the water when the at least one alkali metal salt is dissolved in the water to form a mixed retardant solution; a minor amount of a second fire retarding agent realized in the form of a second alkali metal salt of a nonpolymeric saturated carboxylic acid, specifically, sodium benzoate (SB), for providing metal sodium ions dispersed in the water when the at least one alkali metal salt is dissolved in the mixed retardant solution, for functioning as a secondary fire retardant agent and also inhibiting surface corrosion reactions involving metals contacting the mixed retardant solution, including specific metals, namely 2024-T3 Aluminum, 4130 Steel, Yellow Brass, and Az31B Magnesium; a minor amount of thickening agent in the form of a biomolecular polymer consisting of polysaccharides, for increasing the viscosity of the mixed retardant liquid during application operations; a minor amount of coloring agent in the form of fugitive color dye powder, or non-fugitive pigment powder, for imparting a visible color (e.g. red or green) when the fire retarding biochemical liquid composition is applied to a surface to be protected against fire, as water molecules in the retardant liquid coating evaporate to the environment during drying, to form a thin fire retardant coating deposited on the treated surfaces having a characteristic visible color, and comprising potassium and sodium salt crystals mixed within the polysaccharides of the biomolecular polymer. Wet and dry concentration formulations of the fire retarding biochemical liquid composition are disclosed for use with both serial and ground delivery methods and apparatus.

The invention discloses a cobalt-loaded covalent organic framework material as well as a preparation method and application thereof, and belongs to the technical field of catalyst preparation. The cobalt-loaded covalent organic framework material is prepared by taking a carbonized covalent organic framework as a matrix and cobalt nitrate hexahydrate as a cobalt source, reducing by using a sodium borohydride methanol solution, and introducing transition metal cobalt into the framework through room-temperature impregnation and thermal reduction processes. In the material, active components comprise Co0 and Co < 2 + > which are uniformly distributed on a carrier. Moreover, the metal cobalt is stably loaded in a carbon skeleton through the bonding effect of heteroatoms such as nitrogen and carbon, so that the stability, the catalytic activity and the durability of the metal cobalt are effectively improved, the dissolution risk of the metal cobalt is reduced, the hidden danger of environmental pollution is reduced, and efficient catalytic activity is shown in the aspect of catalyzing and activating peroxymonosulfate to degrade organic pollutants; and good recycling stability is achieved.

The invention discloses a river nitrogen pollutant source analysis method based on drainage basin nitrogen turnover and isotope, and particularly relates to the technical field of water treatment.The river nitrogen pollutant source analysis method comprises the following steps that a drainage basin to be researched is selected, river water and soil samples in the drainage basin are systematically collected, and physical and chemical indexes and isotope indexes # imgabs0 # of the collected samples are tested. Nitrate marked by nitrogen isotope delta 15N / delta 18O and # imgabs1 # are used as key indication marks to perform high-precision identification on nitrogen sources in a river and an environmental system, the contribution proportion of different nitrogen sources to the nitrate concentration in a water body is quantified through a stable isotope analysis model, and the concentration of the nitrate in the water body is calculated. And in combination with data, the rates of denitrification and anaerobic ammonia oxidation in environmental samples, sediments and soil are directly measured through combined application of an isotopic tracer technology and a membrane inlet mass spectrometer technology.

The invention discloses a composite rare earth modified aluminum oxide fluorine removal agent as well as a preparation method and application thereof, and belongs to the technical field of wastewater treatment. The preparation method comprises the following steps: dipping Al2O3 powder into a rare earth nitrate solution, oscillating at constant temperature, filtering, washing, drying, grinding and sieving to obtain the composite rare earth modified aluminum oxide fluorine removal agent; the rare earth nitrate solution contains two or more rare earth nitrates. The rare earth nitrate solution is adopted to modify aluminum oxide, and active sites on the surface of the aluminum oxide are increased due to loading of rare earth metal elements, so that the chemical affinity of the aluminum oxide and fluorine ions is improved, the adsorption capacity of the aluminum oxide fluorine removal agent to the fluorine ions is improved, and the service life of the aluminum oxide fluorine removal agent is prolonged. Finally, the purpose of improving the fluorine removal efficiency and the fluorine removal capacity of the aluminum oxide fluorine removal agent is achieved, and meanwhile toxic and harmful chemical substances cannot be introduced into water.

The invention relates to the technical field of composite catalyst materials, in particular to a ferrocobalt bimetal hydroxide / BCN composite material and a preparation method and application thereof.The preparation method comprises the steps that cobalt nitrate and ferric nitrate are used for preparing a metal salt solution, sodium carbonate and sodium hydroxide are used for preparing a precipitant solution, a B-doped carbon nitride BCN material is added into the metal salt solution to form a uniform suspension, and the suspension is dried to obtain the ferrocobalt bimetal hydroxide / BCN composite material; dropwise adding the precipitant solution into the suspension to obtain a precursor solution, performing hydrothermal reaction on the precursor solution, and performing centrifugal impurity removal and drying to construct a heterostructure between layered double hydroxide and BCN in situ to obtain the Co-Fe LDH-coated BCN composite material. Through boron doping and heterostructure construction, the charge separation capacity of graphite carbon nitride is enhanced, the electron migration efficiency is improved through a heterointerface structure, the metal ion release amount and the cycle stability are controlled, and the catalytic performance is remarkably improved.

The invention discloses a complex microbial inoculant for treating underground water as well as a preparation method and application thereof, relates to the field of sewage treatment, and aims to solve the problem that TBBPA and nitrate in underground water are difficult to remove at the same time in an existing biological treatment method. The composite microbial agent is prepared from pseudomonas koreensis Y5-11, acinetobacter pidermatum LYS-5, Pseudomonas sp. Y39-6 and psychrophilic bacteria F5-6, and the pseudomonas sp. Y5-11, the acinetobacter pidermatum LYS-5, the Pseudomonas sp. Y39-6, the psychrophilic bacteria F5-6 and the psychrophilic bacteria F5-6 are added into the microbial agent. The four strains are respectively subjected to fermentation culture, and the four fermentation liquids are mixed to prepare the complex microbial inoculant. The four bacteria in the complex microbial inoculant have a stronger metabolism complementation effect, and the effect on composite pollution remediation is more remarkable. The complex microbial inoculant is used for removing TBBPA and nitrate in underground water at the same time, the complex microbial inoculant has biodiversity, and the treatment result conforms to the water quality characteristics of the underground water.

The invention relates to a detection method for determining isotope abundance of a 15N or 18O labeled nitrate sample by using an organic mass spectrum. The detection method comprises the following steps: (1) dissolving the 15N or 18O labeled nitrate sample in a methanol aqueous solution; (2) taking the supernatant, filtering with a filter membrane, and diluting with a methanol aqueous solution to obtain a solution to be detected; and (3) detecting the solution to be detected by using a high-resolution liquid chromatograph-mass spectrometer, selecting a mass spectrum in a peak appearance time window, recording relative mass spectrum signal intensities with mass-to-charge ratios of 61.988 and 62.985, and calculating to obtain the 15N isotope abundance. Or recording the relative mass spectrum signal intensities with the mass-to-charge ratios of 61.988, 63.993, 65.997 and 68.001, and calculating to obtain the abundance of the < 18 > O isotope. Compared with the prior art, the method has the advantages that the sample pretreatment time is greatly shortened, the economic cost is low, and the test result is accurate.

The invention discloses a preparation method and application of a magnetic biochar-loaded bacterium composite functional material, magnetic biochar (MBC) is used as a carrier to load and fix Achromobacter denitrificans BP1 (Achromobacter denitrificans BP1, the NCBI login number is CP154792), and a magnetic biochar-loaded functional bacterium (MBC-coated BP1) is obtained. The invention relates to a water and soil purifying agent which is used for removing pollutants in water and / or soil, the pollutants comprise polycyclic aromatic hydrocarbons (PAHs) and / or heavy metals (HM) and the like, benzo [a] pyrene (BaP) and phenanthrene (Phe) in the soil can be efficiently degraded, Cr (VI) is removed, nitrate (NO3 <->) is metabolized, the soil nutrient level (organic matters, nitrogen, phosphorus and the like) can be increased, the diversity and structural functions of soil microbial communities are improved, and the water and soil purifying agent can be used for purifying water and / or soil. And a green and efficient repairing material and a technical support are provided for a compound pollution complex site.

The invention discloses a preparation method of a modified electrode based on carbon nanofibers and application of the modified electrode in efficient reduction of nitrate and removal of associated organic matters, and belongs to the crossing field of materials science, chemistry and environmental engineering. The preparation method comprises the following steps that firstly, foamed nickel is pretreated, then, carbon nanofibers are loaded on the pretreated foamed nickel through an impregnation and calcination method, and finally, metal copper is deposited on the surfaces of the carbon nanofibers through an electro-deposition method. The introduction of the carbon nanofibers provides a larger specific surface area for the metal copper, promotes the high dispersion of metal copper nanoparticles, and affects the formation of a copper crystal face, thereby significantly improving the catalytic activity of the electrode. The electrode prepared by the method has excellent electro-catalytic performance, is relatively low in cost, is easy to operate and control, and is easy to realize industrial production. The electrode can simultaneously realize efficient reduction of nitrate and degradation of organic matters in an electro-catalysis system, and has a wide application prospect.

The invention discloses a self-template synthesized linear biochar-based bimetallic material as well as a preparation method and application thereof, and belongs to the technical field of carbon materials. The method comprises the following steps: pretreating ganoderma lucidum residues, and pyrolyzing in a nitrogen atmosphere to prepare charcoal; and mixing the prepared biochar with cobalt nitrate and sodium molybdate to prepare CoMoO4 nanoparticles with in-situ growth of the biochar, and then washing and drying to obtain the BC-coated CoMoO4 linear biochar-based bimetallic material. Heterojunctions formed by binding sites of cobalt-molybdenum bimetal and biochar in the material form more defect sites, the synergistic effect of the metal and the micro-nano fibrous biochar is exerted, the degradation rate in the application of catalytic degradation of bisphenol A can reach 98.18% or above, a multiple reaction mechanism with sulfate free radicals is jointly shown, and the photocatalytic degradation of bisphenol A is realized. And the method has higher adaptability and effectiveness for complex pollutants.

The invention discloses a catalytic combustion catalyst for treating CVOCs (Chemical Volatile Organic Compounds) as well as a preparation method and application of the catalytic combustion catalyst. The preparation method comprises the following steps: (1) impregnating and loading cerous nitrate and trimethyl phosphate on a carrier, drying, and roasting at 600-800 DEG C to form a modified carrier containing a cerous phosphate crystal phase; and (2) impregnating and loading active metal ruthenium on the modified carrier, drying and roasting to obtain the catalyst for treating catalytic combustion of the CVOCs. The catalyst provided by the invention can be used for catalytic combustion degradation of CVOCs such as dichloromethane, chlorobenzene, chloroethylene, dichloroethane, dichloroethylene, oxychloropropane and the like. For catalytic combustion degradation of CVOCs, the catalyst disclosed by the invention can show high activity, high chlorine-resistant stability, low polychlorinated by-product selectivity and thermal stability, and has certain industrial application prospects.

The invention discloses a preparation method of an MOF-on-MOF material, and belongs to the technical field of electrocatalysts.The preparation method comprises the steps that firstly, nickel acetate tetrahydrate and terephthalic acid are added into a mixed solvent composed of deionized water and N, N-dimethylacetamide, stirring reaction is conducted at the temperature of 140-160 DEG C, and Ni-MOF is synthesized; mixing and dissolving ferric nitrate nonahydrate and cobalt nitrate in a molar ratio of 1: 5 in deionized water, then adding a sodium acetate aqueous solution, and synthesizing a Fe2Co (mu3-O) cluster after stirring reaction; and then adding the Ni-MOF and the Fe2Co (mu3-O) cluster into deionized water, carrying out ultrasonic treatment, carrying out solid-liquid separation, and washing and drying a solid product to obtain the Ni-MOF / Fe2Co (mu3-O) cluster. Compared with an existing method, the method is easy to operate and low in cost, and the prepared MOF-on-MOF material has excellent electrocatalytic activity and stability in an electrocatalytic oxygen evolution reaction and is particularly suitable for being used in the field of hydrogen production through water electrolysis.

The invention provides an efficient environment-friendly petroleum passivator as well as a preparation method and application thereof, and belongs to the technical field of passivators. The preparation method comprises the following steps: reacting bismuth nitrate with tetra (4-carboxyl phenyl) porphyrin and benzoic acid to prepare a carboxyl phenyl porphyrin bismuth-MOF material, reacting antimony nitrate with tetra (4-pyridyl) porphyrin and benzoic acid to prepare a pyridyl porphyrin antimony-MOF material, and performing sol-gel reaction on lanthanum isopropoxide and cerium isopropoxide to prepare lanthanum-cerium sol; the preparation method comprises the following steps: mixing calcium nitrate, magnesium chloride, organic acid, organic amine and hydrogen peroxide for reaction to prepare a calcium / magnesium organic matter, mixing the calcium / magnesium organic matter with other substances, adding the mixture into an acetonitrile / ethanol mixed solvent, and uniformly stirring and mixing to prepare the efficient environment-friendly petroleum passivator. The high-efficiency environment-friendly petroleum passivator prepared by the invention is green, safe, non-toxic and efficient, has better capturing and passivating effects on metal ions such as nickel and vanadium in the catalytic cracking reaction process of heavy oil, improves the activity of a catalyst, prolongs the service life of the catalyst, and thus, has a wide application prospect.

The embodiment of the invention discloses a low-corrosion metal system for capturing CO2 through an electrochemical mediation amine regeneration method and a preparation method of the low-corrosion metal system. The method comprises the steps that metal copper Cu serves as an electrode, and an organic amine MMEA aqueous solution doped with non-corrosion sodium salt serves as an absorbent; the absorbent saturated by CO2 absorption is used as anode liquor; and a solution obtained after a Cu-MMEA complex is fully formed in the anolyte serves as catholyte, and the Cu-MMEA metal system is prepared. According to the preparation method of the low-corrosion metal system for capturing CO2 through the electrochemical mediation amine regeneration method, the non-corrosion salt is introduced into the cathode electrolyte and the anode electrolyte, so that the problem that a chlorine-containing solution and a nitrate-containing solution corrode stainless steel in long-term use is solved, and the performance is not affected.

The invention relates to a preparation method of a nano-catalyst based on a bimetallic organic framework material, and a product and application thereof, the preparation method comprises the following steps: (1) mixing 1, 4-terephthalic acid and N, N-dimethylformamide to obtain a solution A, mixing the solution A with formic acid, ceric ammonium nitrate and zirconyl nitrate to synthesize a bimetallic organic framework material Ce / Zr-UiO-66; and (2) carrying out impregnation and reduction on a metal salt precursor to obtain the nano-catalyst based on the bimetallic organic framework material. According to the method disclosed by the invention, the Zr site part is replaced by Ce in the Zr6O8 cluster at the UiO-66 node through one-pot synthesis, and the anchoring of the ultra-small nano metal is realized; the catalyst realizes catalysis of carbon dioxide hydrogenation methanation under mild conditions, and shows the advantages of high methane selectivity, high conversion rate and long-time stability.

The invention relates to a method for determining potassium by using a nano-enzyme-based colorimetric probe, and the probe and application thereof. The invention relates to a method for determining potassium by using a nano-enzyme-based colorimetric probe, which comprises the following steps of: synthesizing copper and cerium-containing phosphotungstic acid nano-enzyme by using phosphotungstic acid, cerous nitrate and copper chloride as precursors through a hydrothermal method, detecting the absorbance of K < + > standard solutions with different concentrations by using the copper and cerium-containing phosphotungstic acid nano-enzyme as a probe, establishing a quantitative relation between the absorbance and the K < + > concentration, drawing a standard curve, obtaining a regression equation, and determining the potassium content by using the regression equation. And detecting the absorbance of the sample determination standard solutions with different concentrations, and obtaining the K < + > content of the sample through the regression equation. According to the method, the nano-enzyme (Cu, Ce-PWs) is prepared by using tungsten-molybdenum heteropoly acid with high negative charges, unique chelating properties and various structures and Ce < 4 + > and Cu < 2 + > as raw materials, strong mimic enzyme laccase activity is generated through the synergistic effect of Ce atoms and Cu atoms, and the activity of the mimic enzyme laccase is further improved in the presence of H2O2.

A method for the preparation of carboxylic acid esters by iron-catalyzed oxidation esterification of alcohols. The present invention discloses a method for directly oxidizing and esterifying alcohols to prepare carboxylic acid ester compounds with oxygen or air as the oxidant under iron catalysis. The method is carried out at 25 °C - 60 °C in an organic solvent, using iron nitrate (Fe(NO3)3·9H2O), nitrogen oxides and Lewis acid as catalysts, and oxygen or air as the oxidant, and the alcohol is directly oxidized and esterified to form carboxylic acid ester compounds. The present invention has many advantages such as simple operation, cheap and easily available catalysts and raw materials, mild reaction conditions, excellent yield, good compatibility of substrate functional groups, scalable reaction scale, environmentally friendly reaction process and no pollution, and has the prospect of industrial application.

The invention relates to nano W-Re-Y2O3 alloy powder with small particle size and a preparation method of the nano W-Re-Y2O3 alloy powder with small particle size, and the nano W-Re-Y2O3 alloy powder with small particle size comprises the following components in percentage by mass: 79-94 wt.% of W, 10-20 wt.% of Re and 1-5 wt.% of Y2O3, the small-particle-size nano W-Re-Y2O3 alloy powder is prepared through a sol-gel method and specifically comprises the steps that firstly, citric acid is dissolved in deionized water, then ammonium metatungstate, ammonium perrhenate and yttrium nitrate are added, water bath heating is conducted, and stirring is conducted till colloid is formed; drying and calcining the colloid to obtain nano oxide powder; and putting the nano oxide powder into a reaction furnace, and reducing the nano oxide powder by using hydrogen to obtain W-Re-Y2O3 powder. According to the method, W and Re are combined on the atomic scale through a sol-gel method, Y2O3 particles are generated in situ during calcination, the Y2O3 particles are evenly mixed in the powder, the average particle size of the prepared alloy powder particles is about 12 nm, and the reduced powder does not need to be subjected to follow-up treatment. The preparation method is simple, the raw material cost is low, and large-scale production is easy to realize.

The invention discloses a preparation method of a beaded cobalt-doped Bi25FeO40 / BiFeO3 nanofiber wave-absorbing material, which comprises the following steps: obtaining a precursor by a standing method, and adding the precursor, bismuth nitrate, ferric nitrate and a spinning aid into a mixed solvent compounded by N, N-dimethylformamide and absolute ethyl alcohol to obtain a spinning solution; spinning the spinning solution by adopting an electrostatic spinning technology to obtain a nanofiber membrane; and finally, drying and calcining to obtain the wave-absorbing material. According to the wave-absorbing material, multiple reflection and scattering of electromagnetic waves are increased, the absorption performance of the electromagnetic waves is improved, due to the fact that a heterogeneous interface is generated after two phases are compounded, the interface polarization loss is further increased, when the thickness of the wave-absorbing material is 2.33 mm, the minimum reflection loss reaches-56.01 dB, the effective absorption frequency band width is 6.32 GHz, and the whole Ku wave band is covered.

The invention belongs to the technical field of nano composite materials, and relates to a preparation method and application of a difunctional nano enzyme Eu (at) Ce-MOF. According to the invention, ceric ammonium nitrate is used as an inorganic metal source, terephthalic acid is used as an organic ligand, and Ce-MOF is synthesized in one step by using a hydrothermal method; and then introducing europium nitrate hexahydrate and sodium citrate to prepare the Eu (at) Ce-MOF composite material through one-step in-situ functionalization. Ce-MOF is functionalized by using europium nitrate hexahydrate, and second metal activity is introduced, so that the bi-metal synergistic effect is realized to enhance the peroxidase-like activity of the composite material; meanwhile, the introduced Eu < 3 + > is used as a recognition element and has specific recognition capability on Pi, specific recognition sites of the Eu-coated Ce-MOF composite material are increased, and the difunctional nano-enzyme with strong enzyme-like activity and specific recognition capability is prepared.

The invention relates to the technical field of catalysis, in particular to a Ru / WO3-x heterojunction catalyst, the chemical formula of the catalyst is Ru / WO3-x, and x represents oxygen vacancy; ru is loaded on the surface of a WO3-x support in the form of a metal simple substance, and the preparation method comprises the following steps: by taking tungstate as a tungsten source, ammonium sulfate as a morphology adjuvant and ruthenium trichloride as a ruthenium source, adjusting the pH value to 0-2, adding deionized water to prepare a hydrothermal reaction solution, performing hydrothermal reaction with a current collector, washing with deionized water, and drying, thereby obtaining the WO3-x support. And calcining in a reducing gas atmosphere to obtain the Ru / WO3-x heterojunction catalyst integrated electrode. Under the same test condition, nitrate can be effectively inhibited from being excessively hydrogenated into the final product ammonia, so that the product stays in the intermediate hydroxylamine.

The invention provides a cobalt metal organic framework material for separating hexafluoropropylene / octafluoropropane mixed gas as well as a preparation method and application thereof. The chemical formula of the cobalt metal organic framework material is [Co3 (OH) (C6H3O2NCl) 5 (H2O)], the cobalt metal organic framework material belongs to a monoclinic system, the space group is P21 / c, and the unit cell parameters are as follows: # imgabs0 # alpha = 90 degrees, beta = 92.7-92.8 degrees, gamma = 90 degrees and Z = 4; wherein OH represents a hydroxyl group; c6H3O2NCl represents 3-chloroisonicotinic acid without a hydrogen atom of a formic acid group; h2O is a water molecule. The preparation method comprises the following steps: placing cobalt nitrate hexahydrate, 3-chloroisonicotinic acid and an organic solvent in a glass bottle, adding fluoboric acid, and reacting at 363-383 K to obtain the cobalt metal organic framework material. The cobalt metal organic framework material can be used for separating hexafluoropropylene / octafluoropropane mixed gas, so that pure octafluoropropane gas is obtained.

Disclosed is a system and method for effectively converting nitrogen pollutants, including nitrates, into ammonia. The system includes an electrolyzer unit capable of facilitating conversion of nitrates to ammonia. The resulting mixture leaving the cathodic compartment, including ammonia and any unreacted nitrogen pollutants, is directed to an ammonia separator where ammonia is separated from any unreacted nitrogen pollutants of the stream. Residual nitrogen pollutants are then recirculated back to the electrolyzer unit, enabling the system to operate in a continuous loop.

The invention provides a cobalt modified multistage heterostructure catalyst and a preparation method and application thereof, and belongs to the technical field of ammonia synthesis. The cobalt modified Con-Cu3P / Cu catalyst is prepared by depositing copper and cobalt on a substrate step by step and then carrying out calcination, phosphorization and electrochemical reduction. In the catalyst, the metal Co mainly exists in the catalyst in the form of an elementary substance, Cu exists in the form of elementary substance Cu and monovalent Cu3P, and the problem that protonation of an intermediate is limited is solved by modifying and regulating an electronic structure through Co. The Co-Cu3P / Cu catalyst is used for electro-catalysis nitrate reduction reaction (NO3RR), and sustainable green ammonia (NH3) synthesis and nitrate (NO3 <->) pollutant removal can be achieved.

The invention provides a monatomic cobalt-based composite catalyst, a preparation method of the monatomic cobalt-based composite catalyst and application of the monatomic cobalt-based composite catalyst to degradation of antibiotics by activating peroxymonosulfate, and belongs to the technical field of advanced oxidation. The method comprises the following steps: mixing biomass powder and water to obtain a biochar suspension, adding cobalt nitrate hexahydrate into the biochar suspension, centrifuging the mixed solution, collecting residues, and drying to obtain a sample; and pyrolyzing the sample in a protective gas atmosphere, taking out, cooling, washing, and drying to obtain the monatomic cobalt-based composite catalyst. The cobalt-based catalyst prepared by the invention has high specific surface area, abundant pore structures and a large number of active sites, and is beneficial to activation of PMS and degradation of pollutants; the cobalt-based composite catalyst prepared by the method is used for activating peroxymonosulfate to degrade tetracycline, and the removal rate of tetracycline in a solution is greater than 99% after reaction is carried out for 20 minutes under a dark condition.

The invention belongs to the technical field of hydrometallurgy, and particularly relates to a nickel-cobalt solution deep purification method which comprises the following steps: (1) oil removal: removing oil from a nickel-cobalt solution with activated carbon to obtain an oil-removed solution; the nickel-cobalt solution is selected from one of cobalt nickel sulfate, cobalt nickel chloride and cobalt nickel nitrate, and the nickel-cobalt solution contains oil; (2) adjusting the pH value: adding inorganic acid or liquid caustic soda into the oil-removed solution, and adjusting the pH value of the solution to 3.0-4.0 to obtain a carbon-removed solution; and (3) carbon removal: transferring the pre-carbon-removal solution into an electrolytic bath, respectively inserting a cathode plate and an anode plate into the pre-carbon-removal solution, electrifying, carrying out electric flocculation carbon removal, and carrying out refined filtration after carbon removal to obtain the purified nickel-cobalt solution. According to the method, only a small number of anodes are consumed, new impurities are not introduced, the cleanliness of the solution is high, and the finally obtained nickel-cobalt solution is suitable for producing high-purity nickel salt, cobalt salt crystals, metal nickel and metal cobalt and has important significance on extraction and application of high-purity nickel and cobalt.

The invention relates to the technical field of electrochemical catalysis, and particularly discloses a preparation method of a cobalt-based catalyst for synthesizing ammonia through electrocatalysis of nitrate. The method comprises the following steps: placing melamine on the upstream of ZIF-67 powder, carrying out two-step temperature-programmed pyrolysis treatment in a high-purity nitrogen protective atmosphere, and naturally cooling to obtain the cobalt-based catalyst which takes rhombic carbon as a substrate and on which Co-NC nanoparticles are anchored. In the prepared catalyst, nitrogen atoms are doped on the surfaces of cobalt clusters to form Co-NC sites, the local electronic structure of cobalt can be accurately regulated and controlled, and the Faraday efficiency and yield of electrocatalytic nitrate reduction synthesis of ammonia are effectively improved.

The invention discloses a preparation method of a modified red-mud-based chlorobenzene catalyst, which comprises the following steps: taking solid waste red mud as a main component, adding a certain amount of acid for dissolving, dropwise adding alkali liquor to enable the pH value of red mud suspension to reach 8-9, washing to be neutral, drying, grinding, passing through a molecular sieve, and roasting to obtain red-mud-based catalyst carrier powder; the red-mud-based catalyst carrier powder is mixed with a nitrate solution, it is guaranteed that the active component loading content in the mixed solution is 10-20%, and a filter cake loaded with the active component is roasted and then ground to obtain the red-mud-based catalyst. According to the method, the solid waste red mud is subjected to resource utilization, the red mud is modified into the efficient and low-cost catalyst to be applied to catalytic oxidation of volatile organic compounds, volatile organic compound waste gas is eliminated, the atmospheric environment quality is improved, waste is turned into wealth, and pollution is treated with waste.

The invention relates to the technical field of catalysts, in particular to preparation and application of a B-site La-doped magnetic nano ZnFe2O4 catalyst.The preparation method of the catalyst comprises the following steps that zinc nitrate, ferric nitrate, lanthanum nitrate and cerous nitrate are selected as base materials, the molar ratio of the zinc nitrate to the ferric nitrate to the lanthanum nitrate to the cerous nitrate is 1: 1.5: 0.5: 0.3, and the molar ratio of the zinc nitrate to the ferric nitrate to the lanthanum nitrate to the cerous nitrate is 1: 1.5: 0.5: 0.3; zinc nitrate, ferric nitrate, lanthanum nitrate and cerous nitrate are dissolved in a eutectic solvent in proportion, then modified citric acid is added as a complexing agent for mixing, and carbon nanotube powder and zinc acetate are added in the process. According to the scheme provided by the invention, the B site of the catalyst is directionally occupied by La, Zn < 2 + > activity loss caused by A site doping is avoided, the stability and catalytic effect of the catalyst are improved by adding Ce, the carbon nanotubes and zinc acetate, and the removal rate of the catalyst to high-concentration or refractory organic matters is improved.