1549 results about "Nitrate salts" patented technology

The invention provides a sewage treatment carbon source adding control method, and relates to the technical field of sewage treatment, and the method comprises the following steps: obtaining water inlet parameters of a water inlet end of sewage to be treated and process parameters of a treatment section, the water inlet parameters comprising chemical oxygen demand, total nitrogen, total phosphorus and flow; the process parameters comprise the phosphate concentration at the tail end of an anaerobic tank, the nitrate concentration at the tail end of an anoxic tank, and the total nitrogen and chemical oxygen demand of inlet water of a denitrification filter tank; dynamically calculating a predicted carbon-nitrogen ratio and a predicted carbon-phosphorus ratio in real time according to water inlet parameters and the process parameters; based on the predicted carbon-nitrogen ratio, the predicted carbon-phosphorus ratio and a preset effluent quality standard, a carbon source adding point and a first carbon source adding amount are determined, and the carbon source adding point comprises at least one of an anaerobic tank, an anoxic tank and a denitrification filter tank; according to the carbon source feeding point and the first carbon source feeding amount, the carbon source feeding device is controlled to execute corresponding feeding operation, through segmented feeding and closed-loop control, COD standard exceeding caused by excessive carbon sources is avoided, and secondary pollution is effectively inhibited.

The invention discloses a fluoride salt-free nitrate-free cast iron enamel semitransparent glaze as well as a preparation method and application thereof, and belongs to the technical field of enamel. The semitransparent glaze is prepared from quartz, anhydrous borax, sodium carbonate, potassium carbonate, calcium carbonate, potassium feldspar, zinc oxide, lithium carbonate, zirconium silicate, titanium dioxide, aluminum oxide, trisodium phosphate, antimony oxide, magnesium carbonate and barium carbonate according to a specific mass ratio. The preparation method comprises the steps of raw material mixing, high-temperature melting under a pure oxygen condition, wiredrawing detection, quenching and the like. The semitransparent glaze is completely free of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are avoided from the source, the fluorine content of the product is not detected through detection, the product meets the requirements of European Union REACH regulations, meanwhile, the product has good porcelain surface, luster and low-temperature firing adaptability, and is suitable for cast iron matrixes, the firing temperature is 740-760 DEG C, and the firing time is 2-3 hours. The method can be used for producing green and environment-friendly enamel products.

The invention belongs to the technical field of rare earth functional materials, and particularly relates to a rare earth aluminate low-temperature magnetic refrigeration material and a preparation method and application thereof.The preparation method comprises the following steps that 1, rare earth metal nitrate and aluminum nitrate are added into water to be mixed, and a mixed solution is prepared; adding ammonia water into the mixed solution to prepare a precipitate; (2) carrying out annealing treatment on the precipitate to prepare a metal oxide; and (3) calcining the metal oxide to obtain the rare earth aluminate low-temperature magnetic refrigeration material. The rare earth aluminate which has the characteristics of stable structure, low preparation cost, strong mechanical property, high magnetic density and the like and is prepared by adopting a coprecipitation method and combining a high-temperature sintering technology has more excellent magnetocaloric properties in a low-temperature region.

The invention discloses an A-site high-entropy solid oxide fuel cell cathode material as well as a preparation method and application thereof, and provides an A-site high-entropy solid oxide fuel cell cathode material Pr < 0.2 > M < 0.2 > La < 0.2 > Ba < 0.2 > Sr < 0.2 > Co < 0.8 > Fe < 0.2 > O < 3-delta > with a perovskite phase. The preparation method comprises the following steps: S1, weighing multi-element metal nitrates, and mixing to obtain a first mixed solution; s2, dissolving ethylenediamine tetraacetic acid in ammonia water to obtain a second mixed solution; mixing the first mixed solution, the second mixed solution and citric acid to form a mixed precursor solution; s3, carrying out second heating treatment on the mixed precursor solution, and adjusting the pH value to form a gel precursor; and S4, carrying out pre-sintering treatment, third heat treatment and calcination treatment on the gel precursor to obtain a high-grade powder precursor, and carrying out ball milling and sieving treatment to obtain the A-site high-entropy solid oxide fuel cell cathode material. The cathode material is high in stability and good in chemical compatibility with a barrier layer GDC, provides high-quality mass transfer channels and active sites for O2 / O- / O2-, and has good electrochemical performance at medium and low temperatures.

The present application provides a control method for adding a carbon source to sewage treatment, which relates to the technical field of sewage treatment, comprising the following steps: obtaining water inlet parameters of the sewage to be treated and process parameters of the treatment section, the water inlet parameters including chemical oxygen demand, total nitrogen, total phosphorus and flow rate, and the process parameters including phosphate concentration at the end of the anaerobic tank, nitrate concentration at the end of the anoxic tank, total nitrogen and chemical oxygen demand of the denitrification filter inlet; dynamically calculating and predicting the carbon-nitrogen ratio and the carbon-phosphorus ratio in real time based on the water inlet parameters and the process parameters; determining a carbon source addition point and a first carbon source addition amount based on the predicted carbon-nitrogen ratio, the predicted carbon-phosphorus ratio and a preset effluent water quality standard, the carbon source addition point including at least one of the anaerobic tank, the anoxic tank and the denitrification filter; controlling a carbon source addition device to perform corresponding addition operations based on the carbon source addition point and the first carbon source addition amount, and avoiding excessive COD caused by excessive carbon source through segmented addition and closed-loop control, thereby effectively suppressing secondary pollution.

A low-carbon near zero emission process of industrial waste water, comprising: S1: entering industrial waste water into a pre-oxidation system to improve biodegradability of organics; S2: after treatment in the pre-oxidation unit, entering the waste water into an anaerobic biological treatment system, sodium chloride and sulfate is deeply removed and carbon sources in the waste water can be used to remove the sulfate and nitrate; S3: entering water output from the anaerobic biological treatment system into a membrane concentration system and membrane concentrated solution enters a nano-filtration salt fractionation system for salt fractionation; and S4: refluxing nano-filtration concentrate solution generated by the nano-filtration salt fractionation system to the anaerobic biologic treatment system for biological desulfurization, or synthesizing the nano-filtration concentrate solution to be sodium persulfate by electro chemical methods, and refluxing proportionately to a waste water pre-oxidation system for use in-situ.

The invention discloses silver powder with a high twin crystal ratio and a preparation method and application of the silver powder with the high twin crystal ratio. The preparation method comprises the following steps that S1, a carboxylic acid coordination agent is added into a silver source solution, and a silver precursor solution is obtained; sequentially adding a dispersing agent and an initiator into the reducing agent solution to obtain a reaction base solution; s2, a silver precursor solution is added into the reaction base solution for an oxidation-reduction reaction, then curing is conducted, and mixed mother liquor is obtained; s3, the mixed mother liquor is filtered, washed, dispersed and dried, and then the silver powder with the high twin crystal proportion is obtained; the initiator comprises one or more of sulfate, carbonate and nitrate; through the synergistic effect of the initiator and the carboxylic acid coordination agent, the silver ion release rate and the crystal nucleus preferential growth direction are regulated and controlled, the rapid feeding and curing technology is combined, the low supersaturation environment is constructed, the silver powder is induced to grow in the specific direction, and the twin crystal proportion is remarkably increased.

The invention discloses a high-activity short-cut nitrification quick-start long-term stable operation process, which relates to the technical field of biological sewage treatment, and comprises the following steps: inoculating sludge, carrying out anaerobic fermentation pretreatment, and removing expanded sludge and sludge foam in combination with quick sludge discharge and manual removal; controlling the number of days of sludge age, reproliferating the sludge, enriching ammonia oxidizing bacteria, and inhibiting and elutriating nitrite oxidizing bacteria; long-term operation is carried out under the condition of no sludge discharge, the abundance and activity of ammonia oxidizing bacteria are maintained, and meanwhile, the abundance of nitrite oxidizing bacteria is controlled; the proliferation of nitrite oxidizing bacteria is controlled by using the predation effect of protozoa and metazoan, and the accumulation rate of nitrite in the reactor is controlled; monitoring the dissolved oxygen, the pH value and the concentrations of ammonia nitrogen, nitrite nitrogen and nitrate nitrogen in the reactor in real time, and regulating and controlling the influent ammonia nitrogen load and the free ammonia concentration; dissolved oxygen distribution is adjusted in an intermittent aeration or microporous aeration mode, and the operation conditions of the short-cut nitrification reactor are optimized. The method is simple to operate, economical and effective.

A process produces unsubstituted or at least singly substituted cycloalkanones by electrochemical oxidation of unsubstituted or at least singly substituted, saturated cycloaliphatic hydrocarbons in the presence of an inorganic or organic nitrate salt in an electrolysis cell in a reaction medium in the presence of oxygen.

A process produces unsubstituted or at least monosubstituted α,ω-dicarboxylic acids and ketocarboxylic acids by electrochemical oxidation of unsubstituted or at least monosubstituted, monounsaturated or polyunsaturated cycloalkenes by electrochemical oxidation in the presence of an inorganic or organic nitrate salt in an electrolysis cell in a reaction medium in the presence of oxygen.

The invention discloses an integrated oil phase emulsion explosive and a preparation method thereof. The emulsion explosive is prepared from the following raw materials: a water-phase component, an oil-phase component and an emulsifier for emulsifying the water-phase component and the oil-phase component, wherein the water-phase component contains a modified oxidant formed by loading a nitrate oxidant component on p-aminophenyl POSS (Polyhedral Oligomeric Silsesquioxane); the preparation process of the modified oxidizing agent comprises the following steps: A, fully dispersing a nitrate oxidizing agent component and p-aminophenyl POSS in an aqueous solution, so that the nitrate oxidizing agent component is fully attached to the p-aminophenyl POSS; and B, separating a solid-phase component, namely the modified oxidant, from the solution system obtained in the step B. According to the integrated oil phase emulsion explosive and the preparation method thereof provided by the invention, the sensitivity and the power can be well considered.

The invention relates to a vertical flow enhanced biological denitrification device and a sewage treatment method, a denitrification agent adding assembly is additionally arranged at a proper position of an existing vertical flow reaction device, namely the outer side of an outer inclined flow guide part, a corresponding enhanced denitrification agent can be added at a selected point position, a denitrification reaction is further enhanced, and the denitrification effect is improved. The selective reaction of the functional microorganism reaction is improved, nitrate generated by the anaerobic ammonia oxidation reaction is consumed, and a sufficient matrix is provided for anaerobic ammonia oxidation, so that the anaerobic ammonia oxidation reaction is greatly promoted, and the total nitrogen removal rate is further improved; by accurately controlling the dosing position and accurately dosing according to the reaction, the nitrogen removal efficiency of the autotroph is enhanced, the coordination of the minimization of the dosing amount of the medicament and the maximization of the nitrogen removal efficiency is realized, and finally, the green, low-carbon, economical and efficient nitrogen removal target of the sewage is achieved.

The invention discloses a device for recovering ammonium sulfate through electrocatalytic reduction and a using method thereof.The device comprises a wastewater pool and an outer shell, a physical filtering bin is fixedly installed in the outer shell, a water inlet of the physical filtering bin is communicated with the wastewater pool, and a water outlet of the physical filtering bin is fixedly connected with a closed electrolytic tank; the upper end of the closed electrolytic tank is fixedly connected with an electrochemical workstation, the lower end surface of the closed electrolytic tank is fixedly provided with a lead-out port, the lead-out port is fixedly connected with a product recovery device, the product recovery device comprises a first chamber and a second chamber, and a gas diffusion port is formed between the first chamber and the second chamber; a gas diffusion film is fixedly installed in the gas diffusion opening, a product discharging opening is fixedly formed in the second cavity, a product discharging valve is fixedly installed at the product discharging opening, and the nitrate reduction device is simple in structure and convenient to use, and the nitrate reduction efficiency is greatly improved.

The invention discloses fluoride-salt-free and nitrate-free medium-temperature semitransparent glaze for steel plate enamel as well as a preparation method and application of the medium-temperature semitransparent glaze, and belongs to the technical field of enamel. The semitransparent glaze is prepared from quartz, potassium feldspar, anhydrous borax, sodium carbonate, titanium dioxide, monopotassium phosphate and zinc oxide according to a specific mass ratio. The preparation method comprises the steps of raw material mixing, high-temperature melting under a pure oxygen condition, wiredrawing detection, quenching and the like. The semitransparent glaze is completely free of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are avoided from the source, the fluorine content of the product is not detected through detection, the product meets the requirements of European Union REACH regulations, meanwhile, the product has good porcelain surface, luster and firing adaptability, is suitable for a steel plate matrix, has the firing temperature of 800-840 DEG C and the firing time of 20-30 minutes, and is suitable for a steel plate. The method can be used for producing green and environment-friendly enamel products.

The invention discloses fluoride-salt-free and nitrate-free high-temperature acid-resistant translucent glaze for steel plate enamel as well as a preparation method and application of the translucent glaze, and belongs to the technical field of enamel. The semitransparent glaze is prepared from quartz, anhydrous borax, titanium dioxide, trisodium phosphate, potassium carbonate, lithium carbonate, aluminum oxide, zinc oxide and sodium carbonate according to a specific mass ratio. The preparation method comprises the steps of raw material mixing, high-temperature melting under a pure oxygen condition, wiredrawing detection, quenching and the like. The semitransparent glaze is completely free of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are avoided from the source, the fluorine content of the product is not detected through detection, the product meets the requirements of European Union REACH regulations, meanwhile, the product has good porcelain surface, luster and firing adaptability, is suitable for a steel plate matrix, has the firing temperature of 840-880 DEG C and the firing time of 820-830 minutes, and is suitable for a steel plate. The method can be used for producing green and environment-friendly enamel products.

The invention belongs to the technical field of nano composite materials, and discloses a novel transition metal-inserted transition metal sulfide composite rare earth oxide photocatalytic material with a solid mediator Z-type heterostructure, and a preparation method and application of the novel transition metal-inserted transition metal sulfide composite rare earth oxide photocatalytic material. The preparation method comprises the following steps: mixing transition metal salt, thioacetamide, nitrate hexahydrate and water to obtain a mixed solution 1; mixing the mixed solution 1 with a hydrazine hydrate solution, and performing hydrothermal reaction to obtain a mixed solution 2; mixing the mixed solution 2 with ammonia water, and sequentially carrying out hydrothermal reaction, drying and calcining to obtain a calcined product; and mixing the calcined product with a sodium borohydride aqueous solution, and drying to obtain the photocatalytic material. The obtained photocatalytic material of the transition metal inserted transition metal sulfide composite rare earth oxide with the solid mediator Z-type body heterostructure has the characteristics of high stability, safe interface contact and rapid charge migration.

The invention discloses a Fe / C loaded membrane module, a PN / A-MABR autotrophic nitrogen removal device, a preparation method and a sewage treatment method, and belongs to the technical field of sewage treatment. According to the invention, the problem that the treatment effect is influenced by NO3 <->-N accumulation in the existing membrane aeration coupling partial nitrification-anaerobic ammonia oxidation process is solved. Comprising a frame and a membrane body attached to the outer portion of the frame, the membrane body comprises a hydrophobic organic membrane layer, an iron-carbon material layer and a biological membrane layer which are sequentially arranged, and the hydrophobic organic membrane layer is attached to the outer portion of the frame. The iron-carbon material is added between the hydrophobic organic membrane layer and the biological membrane layer, the iron-carbon micro-electrolysis process is coupled with the dissimilatory process of nitrate generated by microbial metabolism, the removal of NO3 <->-N generated by anaerobic ammonia oxidation is enhanced, and the total nitrogen removal efficiency is improved.

The invention relates to a photoelectrochemical system for synthesizing urea through co-reduction of carbon dioxide (CO2) and nitrate ions (NO3 <->). The system comprises a solar power supply system, a photoelectrocatalysis (PEC) reaction system, a raw material pretreatment system and a product recovery system. The PEC reaction system is communicated with the raw material pretreatment system and the product recovery system in series; and an integrated coupling reaction system is formed. According to the system, solar energy is used as a main energy source, and a co-reduction reaction of CO2 and NO3 <-> is realized through a novel PEC flow cell device, so that urea is directly synthesized. The reaction liquid is conveyed to a product recovery system through a pipeline, and a high-purity urea product is obtained through evaporative crystallization; unreacted CO2 and NO3 <-> can be circulated to the raw material pretreatment system through the reflux device and are further utilized. The method provided by the invention realizes efficient and green synthesis of urea, optimizes the whole process, reduces energy consumption and system complexity, has good economical efficiency and environmental friendliness, and is suitable for the fields of agricultural fertilizers, waste gas and wastewater resourceful treatment and the like.

The invention discloses fluoride salt-free and nitrate-free low-temperature matte glaze for steel plate enamel as well as a preparation method and application of the low-temperature matte glaze, and belongs to the technical field of enamel. The matte glaze is prepared from quartz, borax pentahydrate, sodium carbonate, titanium dioxide, magnesium oxide, monopotassium phosphate, calcium carbonate, zinc oxide, magnesium carbonate, lithium carbonate, aluminum oxide and zirconium silicate according to a specific mass ratio. The preparation method comprises the following steps: mixing the raw materials, melting at 1300 + / -10 DEG C in a pure oxygen environment, and quenching after wiredrawing to detect a molten state. The matte glaze completely avoids the use of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are eliminated from the source, the fluorine content of the product is not detected through detection, and the limit value requirements of European Union REACH regulations are met. Zinc oxide and ZnO / TiO2 are added, so that the liquid phase viscosity is reduced, ion diffusion is accelerated, and the opacity (opacification performance) and gloss of the porcelain glaze are enhanced.

The invention discloses a fluoride-salt-free and nitrate-free cast iron enamel zirconium white glaze as well as a preparation method and application thereof, and belongs to the technical field of enamel. The zirconium white glaze is prepared from quartz, borax pentahydrate, magnesium carbonate, potassium carbonate, potassium feldspar, zinc oxide, aluminum hydroxide, calcium carbonate, zirconium silicate, sodium tripolyphosphate and lithium carbonate according to a specific mass ratio. The preparation method comprises the steps of raw material mixing, high-temperature melting under a pure oxygen condition, wiredrawing detection, quenching and the like. The zirconium white glaze is completely free of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are avoided from the source, the fluorine content of the product is not detected through detection, the product meets the requirements of European Union REACH regulations, and meanwhile, the zirconium white glaze has good porcelain surface, luster and firing adaptability, is suitable for cast iron matrixes, has the firing temperature of 740-760 DEG C and the firing time of 87-87 hours, and can be widely applied to cast iron substrates. The method can be used for producing green and environment-friendly enamel products.

The experimental equipment for chemical reduction of nitrate in seawater comprises a storage container, a quantitative disc, a reaction bottle, a stirring mechanism, a sealing opening and closing mechanism and a power pump, according to the experimental equipment, zinc particles stored in the storage container can be quantitatively added into the reaction bottle through the quantitative disc, and seawater is quantitatively injected into the reaction bottle through the power pump; the method comprises the following steps of: adding zinc particles into seawater, stirring the seawater and the zinc particles by using a stirring rod, quantitatively extracting a sample solution obtained after reaction by using a power pump, and automatically cleaning a reaction bottle by using the stirring rod, so that full-automatic operation of the reduction process of the nitrate in the seawater can be realized, the extraction efficiency of chemical reduction of the nitrate in the seawater can be improved, and the operation is simple and convenient. And the consistency of the data after multiple times of extraction is ensured.

In a cooperative optimal control system, firstly, two-level models are established to capture the dynamic features of different time-scale performance indices. Secondly, a data-driven assisted model based cooperative optimization algorithm is developed to optimize the two-level models, so that the optimal set-points of dissolved oxygen and nitrate nitrogen can be acquired. Thirdly, a predictive control strategy is designed to trace the obtained optimal set-points of dissolved oxygen and nitrate nitrogen. This proposed cooperative optimal control system can effectively deal with the difficulties of formulating the dynamic features and acquiring the optimal set-points.

The invention relates to the technical field of nitrate production, in particular to a potassium nitrate purification device which comprises a dissolving tank, a filtering device, a crystallization kettle, a centrifugal machine and a drying machine with a steam jacket which are sequentially connected in series through pipelines. The dissolving tank first jacket is connected with a heat source through a circulating pipeline; a liquid outlet of the centrifugal machine is sequentially connected with the cyclone separator, the ceramic membrane filter, the cationic resin column, the first temporary storage tank and the heat source, and the first heat exchanger and the second heat exchanger are sequentially installed between the first temporary storage tank and a heating medium inlet of the heat source. A steam outlet pipeline of the steam jacket is connected with a heat medium inlet of the first heat exchanger, the first heat exchanger is connected with the second temporary storage tank through a pipeline, and the second temporary storage tank is connected with the heat source through a pipeline. A pipeline of the second vacuum unit is connected with a thermal medium inlet of a second heat exchanger, and the second heat exchanger is connected with a second temporary storage tank. According to the method, the potassium nitrate purification efficiency, the product purity, the resource utilization rate and the energy economy are synergistically improved.

The disclosure relates to a method of producing a multi-metal catalyst film and of producing a reactor system for catalytic removal of a wide variety of contaminants (for example, nitrate, nitrite, perchlorate, chlorate, chromate, selenate, chlorophenols, 2,4-D, dicamba, atrazine, trichloroacetic acid, bromochloroiodomethane, NDMA, TCE, TCA, chloroform, freons, RDX, HMX, TNT, PFOA, and PFOS) from water and wastewater. The disclosure also relates to a method of using the multi-metal catalyst for the removal of such contaminants and a system comprising the multi-metal catalyst film for removing such contaminants.

Systems and methods for producing ammonium nitrate are disclosed herein. Exemplary systems can comprise a bioreactor positioned to receive a feed including ammonia. The bioreactor can hold a liquid solution including (i) an ammonia oxidizing bacteria (AOB) and (ii) a nitrite oxidizing bacteria (NOB). The AOB can facilitate oxidation of the ammonia to produce a nitrite at a nitritation rate and the NOB can facilitate oxidation of the nitrite at a nitratation rate. Thus, the bioreactor can produce a mixed liquor comprising a nitrate biologically. The system can further comprise a filter positioned to receive the mixed liquor and produce a permeate and a sludge. A sensor can measure the concentration of the liquid solution of the bioreactor, and a controller coupled to the sensor can regulate the mass flow of nitrogen and / or phosphorus of the bioreactor feed based on the measured concentration of the liquid solution.

The invention discloses fluoride-salt-free and nitrate-free low-temperature pearlescent glaze for steel plate enamel as well as a preparation method and application of the pearlescent glaze, and belongs to the technical field of enamel. The pearlescent glaze is prepared from quartz, anhydrous borax, titanium dioxide, magnesium carbonate, sodium tripolyphosphate, potassium carbonate, lithium carbonate, potassium feldspar, zinc oxide and V-26 according to a specific mass ratio. The preparation method comprises the steps of raw material mixing, high-temperature melting under a pure oxygen condition, wiredrawing detection, quenching and the like. The pearlescent glaze is completely free of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are avoided from the source, the fluorine content of the product is not detected through detection, the product meets the requirements of European Union REACH regulations, meanwhile, the pearlescent glaze has good porcelain surface, luster and low-temperature firing adaptability, is suitable for a steel plate matrix, has the firing temperature of 760-800 DEG C and the firing time of 10-20 minutes, and is suitable for a steel plate. The method can be used for producing green and environment-friendly enamel products.

The invention discloses a CuCo / CoOx catalyst for electrocatalytic nitrate reduction synthesis of ammonia and a preparation method of the CuCo / CoOx catalyst. According to the method, cobalt salt, copper salt and alkali serve as raw materials, an amorphous CoOx layer rich in defects grows on a CuCo alloy substrate in situ through the step of combining hydro-thermal synthesis and low-temperature reduction heat treatment, and therefore the CuCo / CoOx composite catalyst is prepared. The key point of the invention lies in that the interface structure and electronic characteristics of the catalyst can be effectively regulated and controlled by accurately regulating and controlling the time of reduction heat treatment, so that the catalytic performance of the catalyst is optimized. When the prepared catalyst is applied to electrocatalytic nitrate reduction synthesis ammonia reaction, the catalyst shows excellent activity and selectivity in an alkaline medium; under the potential of-0.7 V vs.RHE, the Faraday efficiency of ammonia synthesis can reach 99% or above, and the ammonia yield reaches up to 21.2 mg.h <-1 >. Mg-1. The method provided by the invention has the advantages of simple process, low cost, good controllability and the like, and has important application value in the fields of nitrate wastewater resource utilization and electrochemical green ammonia synthesis.

The invention discloses fluoride-salt-free and nitrate-free low-temperature acid-resistant translucent glaze for steel plate enamel as well as a preparation method and application of the translucent glaze, and belongs to the technical field of enamel. The semitransparent glaze is prepared from quartz, anhydrous borax, titanium dioxide, trisodium phosphate, potassium carbonate, lithium carbonate, aluminum oxide, zinc oxide and sodium carbonate according to a specific mass ratio. The preparation method comprises the steps of raw material mixing, high-temperature melting under a pure oxygen condition, wiredrawing detection, quenching and the like. The semitransparent glaze is completely free of fluoride salt and nitrate, the problems of fluoride emission and environmental protection equipment blockage are avoided from the source, the fluorine content of the product is not detected through detection, the product meets the requirements of European Union REACH regulations, meanwhile, the product has good porcelain surface, luster and low-temperature firing adaptability, and is suitable for steel plate substrates, the firing temperature is 760-800 DEG C, and the firing time is 2-3 hours. The method can be used for producing green and environment-friendly enamel products.

The invention discloses a compatible molybdenum-aluminum mixed acid etching solution which comprises the following components in percentage by mass: 4%-7% of nitric acid, 55%-65% of phosphoric acid, 17%-28% of acetic acid, 0.5%-3% of an oxidizing additive, 0.05%-5% of a metal corrosion inhibitor and 10%-20% of deionized water, and the oxidizing additive is ceric nitrate and at least one selected from sodium nitrate, potassium nitrate and ammonium nitrate; the etching liquid does not contain other organic components except for organic carboxylic acid and organic carboxylate. According to the compatible molybdenum-aluminum mixed acid etching solution, on the basis that ceric nitrate is introduced, the content of nitric acid is reduced, the nitrate ion concentration is increased by adding nitrate, the overall oxidation performance of an etching solution system is improved, the etching rate ratio of different metals is adjusted, CD-Bias is reduced, the etching dip angles of a molybdenum single layer and a molybdenum-aluminum laminated layer are controlled to be kept at 20-50 degrees, and the problem of aluminum thorns is solved. The invention further discloses a molybdenum-aluminum etching method based on the compatible molybdenum-aluminum mixed acid etching solution.

The invention discloses an electroreduction nitrate synthesis ammonia CuOx / CoOx nano material with an oxygen vacancy defect, and a preparation method and application thereof. In the CuOx / CoOx nano material, the molar ratio of a copper element to a cobalt element is 30: (1-8); the particle surface of the CuOx / CoOx nano material is provided with a nano-scale microporous structure; in the microstructure of the CuOx / CoOx nano material, the copper element coexists in the form of a Cu phase, a Cu2O phase and a CuO phase, and the cobalt element exists in the form of a CoO phase and a Co2O3 phase; the CuOx / CoOx nano material is prepared by adopting a coprecipitation method, a hydrothermal method and a calcination method. The CuOx / CoOx nano material is loaded on a cathode of an electrocatalytic reduction nitrate electrolytic tank for electrocatalytic reduction nitrate synthesis ammonia, and the efficiency of the electrolytic tank for catalyzing nitrate synthesis ammonia can be effectively improved.