1143 results about "Nitration" patented technology

The invention belongs to the technical field of wastewater denitrification treatment, and particularly relates to an anaerobic ammonia oxidation reaction-based integrated partitioned denitrification method which comprises the following steps: S1, removing high-concentration organic matters and suspended matters in wastewater through coagulating sedimentation or chemical oxidation pretreatment to avoid inhibition on subsequent Anammox; s2, partitioning the integrated reactor, and setting a short-cut nitrification region and an Anammox reaction region; s3, enabling the effluent part of the Anammox reaction zone to flow back to the short-cut nitrification zone, supplementing nitrite and balancing the carbon nitrogen ratio; the Anammox granular sludge flows back to the reaction zone through the settling zone, and the biomass concentration and the reaction efficiency are maintained; s4, a secondary sedimentation tank or a built-in sedimentation zone is arranged to achieve mud-water separation, residual sludge is discharged, and it is guaranteed that effluent reaches the standard, and it is guaranteed that the denitrification efficiency is stable by dynamically adjusting dissolved oxygen of the short-cut nitrification zone and the pH value of the Anammox reaction zone.

The invention discloses a high-efficiency sulfur-iron-based nitrogen and phosphorus removal and autotrophic denitrification composite filler and a preparation method thereof. The high-efficiency sulfur-iron-based nitrogen and phosphorus removal and autotrophic denitrification composite filler is characterized by comprising the following raw material components in percentage by mass: 1-60% of activated pyrite powder, 30-95% of sulfur, 1-10% of trivalent iron salt and 1-10% of limestone powder. And forming through a thermal compounding process. The preparation method comprises the following specific steps: firstly, activating the pyrite and the magnetic pyrite at high temperature under the protection of protective gas; sulfur is heated to be in a molten state; uniformly mixing the activated pyrite powder, trivalent iron salt and limestone powder to obtain a powdery mixed material; adding the powdery mixed material into molten sulfur, raising the temperature to 125-145 DEG C, and fully and uniformly mixing; and finally, cooling and curing the obtained material to obtain the autotrophic denitrification composite filler. According to the high-efficiency sulfur-iron-based autotrophic denitrification nitrogen and phosphorus removal composite filler prepared by the preparation method, pyrite is calcined and activated, ferric iron salt is used as an oxidizing agent to promote decomposition of the activated pyrite, and the electron donor release capability of the pyrite is improved, so that the high-efficiency nitrogen and phosphorus removal effect of the filler is realized.

The invention relates to the technical field of microorganisms, and discloses a sewage aquatic microbe with ammoxidation capacity, a microbial agent and application of the microbial agent. The strain name of the sewage aquatic microbe is B1, and the preservation number of the sewage aquatic microbe is CCTCC No: M 2025640. The sewage aquatic microbacterium B1 provided by the invention can convert ammonia nitrogen into nitrite nitrogen, so that short-cut nitrification is realized in wastewater treatment, and the strain can tolerate and effectively treat ammonia nitrogen with relatively high concentration, and has relatively good adaptive capacity to environments with different pH values, salinity and temperatures.

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.

The invention belongs to the technical field of sewage treatment, and particularly relates to an anaerobic ammonia oxidation-photoelectric denitrification deep nitrogen removal method. The method comprises the following steps: firstly, adopting a double-chamber reactor; introducing part of sewage into the cathode chamber, carrying out Anammox reaction under a dark state condition to remove ammonia nitrogen and part of nitrite nitrogen, and synchronously generating nitrate nitrogen; turning on a light source to irradiate the anode chamber, exciting photo-induced electrons by a photosensitizer, transmitting the photo-induced electrons to the cathode chamber through an external circuit, and driving the sulfur autotrophic denitrification sludge to reduce residual nitrite nitrogen and nitrate nitrogen generated by Anammox; the total nitrogen removal rate is close to 100%. According to the invention, photo-induced electrons are used as the only denitrification electron donor, so that the addition of a carbon source / sulfide is thoroughly avoided, and the risk of secondary pollution is eliminated. The method is suitable for green low-carbon deep treatment of sludge digestion liquid and pharmaceutical wastewater high-ammonia-nitrogen low-carbon-nitrogen-ratio sewage.

The invention discloses an integrated autotrophic nitrogen removal treatment system with multiple operation modes, comprising: an A / O reactor, the A / O reactor comprising an anoxic zone and an aerobic zone; the ANAMMOX reactor is connected with the A / O reactor, and the ANAMMOX reactor comprises a first ANAMMOX reaction zone and a second ANAMMOX reaction zone; the MBR membrane separation device is connected with the ANAMMOX reactor, an MBR membrane assembly is arranged in the MBR membrane separation device, and the MBR membrane separation device is further connected with a water production unit and a sludge treatment unit; and the autotrophic nitrogen removal control unit is used for controlling the A / O reactor, the ANAMMOX reactor and the MBR membrane separation device. According to the invention, the water inlet proportion and the system operation parameters can be autonomously controlled and adjusted according to the change of the sewage quality, the whole / short-cut nitrification and denitrification coupled anaerobic ammonia oxidation reaction in different operation modes is realized, the removal of ammonia nitrogen and nitrate nitrogen is realized to the greatest extent, and the treatment targets of optimal treatment effect and lowest operation consumption are achieved.

The invention discloses a nitrite concentration monitoring method based on a sensor coupling soft measurement model. The method comprises the following steps: S1, acquiring target influence factor data; determining a plurality of target influence factors based on the water quality parameters and the nitrification process of the to-be-monitored sewage; s2, establishing a soft measurement model; the input of the soft measurement model is the target influence factor, and the output of the soft measurement model is the concentration of nitrite nitrogen; s3, determining the concentration of nitrite nitrogen; according to the method, the target influence factor is firstly acquired by utilizing the sensor, and the nitrite concentration is calculated or predicted in real time by utilizing the target influence factor, so that the problems that monitoring equipment is expensive, the monitoring range is small, the monitoring is inaccurate and the monitoring equipment cannot directly monitor the nitrite in the seriously polluted wastewater in the nitrite monitoring in the prior art can be solved.

The invention discloses a method and a device for preparing CLT acid through pipeline type continuous catalytic hydrogenation reduction. According to the method, catalytic hydrogenation reduction reaction is carried out in the device. According to the method, equipment such as a five-stage static tubular mixer, a gas-liquid separation tank and a reduction liquid temporary storage tank is adopted, so that efficient hydrogenation reduction of the CLT acid nitride is realized. In the reaction process, hydrogen is proportionally introduced by stages through a grading mixer, the hydrogen pressure is controlled to be 0.8-1.0 MPa, and the reaction temperature is controlled to be 70-80 DEG C. The used platinum-carbon catalyst is not recycled and recycled after being filtered and recycled, so that the loss of precious metal platinum is effectively reduced. Through the method, the reduction efficiency of CLT acid is remarkably improved, the generation amount of byproducts and dechlorination products is low, and the nitro conversion rate reaches 99.90% or above. The method has the advantages of small equipment volume, short reaction time, high reaction stability and selectivity, and low catalyst cost.

The invention relates to the technical field of nitrobenzene production, in particular to a method for preparing nitrobenzene by adopting a microreactor under a low-acid condition, the method for preparing nitrobenzene comprises the following steps: introducing a nitrating agent and raw material benzene into the microreactor for nitration reaction to obtain nitrobenzene, the microreactor is provided with at least four reaction modules which are connected in series, a nitrating agent and raw material benzene are fed into the first reaction module, and concentrated sulfuric acid is supplemented into at least one reaction module in other reaction modules except the first reaction module in the nitration reaction process; the effective concentration of sulfuric acid in the nitrating agent is not higher than 77%. The method for preparing nitrobenzene solves the production problems that benzene in a micro-reaction system is poor in reaction stability, incomplete in conversion and large in residual quantity in a low-acid environment, dinitration is affected, and the yield of waste acid is large. Finally, a mechanical application process of the dinitration waste acid and the acidic benzene is realized, the production process is safe and reliable, the operation flexibility is high, and the stability is high.

The invention belongs to the technical field of sewage treatment, and discloses a two-stage MABR-based efficient denitrification system, method and application, the system comprises an MABR-PN / DN reactor, an MABR-PN / A reactor, a peristaltic pump, an aeration hollow fiber membrane module, a carrier, an aeration pump, a gas flowmeter, a pressure gauge and a liquid flowmeter, and the MABR-PN / DN reactor and the MABR-PN / A reactor are arranged along the vertical direction. According to the system, the series design of the MABR-PN / DN and the MABR-PN / A is utilized, the adverse effect of organic matter in sewage on anaerobic ammonia oxidation treatment of high-concentration ammonia nitrogen wastewater is reduced, nitrate nitrogen generated by the MABR-PN / A flows back to the first-stage MABR-PN / DN to achieve denitrification, the denitrification limitation of a single reactor and a single denitrification path is broken through, and the overall total nitrogen removal rate of the system is higher than 90%.

The invention relates to a migration-resistant anti-aging agent as well as a preparation method and application thereof, the method comprises the following steps: taking a substance as shown in a formula I and nitric acid as reactants, condensing H in an amino para-position group-CH-H and nitryl to obtain a nitrated substance, and carrying out hydrogenation reduction on the nitryl of the nitrated substance under the action of a catalyst to obtain an intermediate product. And carrying out hydrogenation on the intermediate product and ketone under the action of a catalyst to obtain a final product, namely the migration-resistant anti-aging agent II. The raw materials are convenient to purchase and transport, the product yield is high, the cost is low, the operation is simple, and the environmental pollution is small, so that the method has an industrial development prospect. # imgabs0 #

The invention provides a plate-type micro-channel reactor and a method for nitrifying trifluoromethoxybenzene by using the plate-type micro-channel reactor, and belongs to the technical field of organic synthesis. The plate type microchannel reactor comprises a first heat exchange plate, a reaction plate and a second heat exchange plate, the reaction plate is positioned between the first heat exchange plate and the second heat exchange plate; a feeding channel, a first shunting section, a first mixing section, a second shunting mixing section, a third shunting mixing section, a fourth shunting mixing section and a discharging channel which are connected in sequence are arranged on the reaction plate; and the feeding channel comprises a first feeding channel and a second feeding channel. According to the method, trifluoromethoxybenzene is taken as a raw material and is subjected to nitration reaction by using plate type micro-channel reactors connected in series, so that high-selectivity continuous nitration of trifluoromethoxybenzene is realized, the nitration reaction can be completed within 5 minutes, and the contents of byproduct meta-position and dinitrate can be controlled to be lower than 0.05% and 0.5% respectively.

The invention relates to the technical field of fine chemical engineering, and provides a method for synthesizing O-methyl-N-nitroisourea by a micro-channel reactor, which comprises the following specific steps: adding nitric acid into a four-neck bottle for cooling, dropwise adding fuming sulfuric acid, controlling the temperature of a mixed solution, adding sulfuric acid into the four-neck bottle, and reacting for 2-4 hours; stirring and a low-temperature constant-temperature reaction bath are started to cool sulfuric acid, disulfate is put into a four-opening bottle to prepare a disulfate sulfuric acid solution, a mixed acid metering pump is started, a disulfate sulfuric acid solution metering pump is started, the disulfate sulfuric acid solution is mixed and enters a nitration micro-channel reaction device, and after heat preservation of nitration liquid is completed, the nitration liquid is dropwise added till the temperature is lowered to 0 DEG C in advance; the preparation method comprises the following steps: adding water into a reaction kettle, dropwise adding while stirring, continuously cooling and preserving heat after dropwise adding, carrying out suction filtration on eluted feed liquid, and washing a filter cake with chilled water to obtain an O-methyl-N-nitroisourea wet product, so that the defects of long production period, low effective productivity, lower safety coefficient and relatively higher safety risk of a traditional method for synthesizing O-methyl-N-nitroisourea are overcome.

The invention relates to the technical field of synthesis of a polymerization inhibitor DNBP, in particular to an efficient production method of the polymerization inhibitor DNBP, which comprises the following steps: step 1, material preparation: selecting corresponding raw materials, weighing and classifying the raw materials, and dividing the raw materials into three main materials, auxiliary materials and additives, the auxiliary material comprises a sulfonic acid type ion exchange resin catalyst, the additive is an ethanol-water mixed solvent, and during weighing, weighing and proportioning are performed according to the molar ratio of nitric acid to o-tert-butylphenol being 2.15: 1 and the mass ratio of o-tert-butylphenol to carbon tetrachloride being 0.15: 1; according to the method, a gradient temperature control strategy is adopted, and a multi-stage microchannel reactor is combined, so that efficient mass and heat transfer of nitration reaction is realized, deep nitration side reaction is inhibited, the content of dinitro isomer impurities is greatly reduced, meanwhile, the total residence time can be accurately controlled, the explosion risk caused by local overheating in a traditional process is avoided, and the method is suitable for industrial production. The reaction selectivity and the safety are obviously improved.

The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of N, N '-bis (2-bromine / chloroethyl) diamino phosphonic acid (1-methyl-4-nitro-1H-imidazole-2-cyanogen) methyl ester, 4-methylimidazole is used as a raw material, and (1-methyl-4-nitro-1H-imidazole-2-cyanogen) methanol is synthesized through nitration, methyl substitution, bromine substitution, bromomethyl substitution, hydrolysis and substitution; the preparation method comprises the following steps: reacting phosphorus oxychloride with ethyl amine salt to synthesize N, N '-bis (2-bromoethyl) diamino phosphonic acid and N, N'-bis (2-chloroethyl) diamino phosphonic acid, and finally condensing to obtain N, N '-bis (2-bromoethyl) diamino phosphonic acid (1-methyl-4-nitro-1H-imidazole-2-cyanogen) methyl ester and N, N'-bis (2-chloroethyl) diamino phosphonic acid (1-methyl-4-nitro-1H-imidazole-2-cyanogen) methyl ester. The compound can selectively inhibit ovarian cancer cell proliferation under a hypoxia condition.

The invention belongs to the technical field of high polymer materials, and particularly discloses a halogen-free flame retardant DOPO-NH2 and a preparation method of halogen-free flame-retardant polyamide of the halogen-free flame retardant DOPO-NH2. The halogen-free flame retardant DOPO-NH2 is prepared by taking DOPO and 1, 4-butanediol as raw materials, and carrying out nitration and hydrogenation reduction reaction. The flame retardant DOPO-NH2 is mixed with binary acid and water to prepare a flame retardant organic salt solution, and then the flame retardant organic salt solution is subjected to polymerization reaction with a polyamide salt solution formed by a salt forming reaction of diamine and binary acid to prepare the halogen-free flame-retardant polyamide resin. The halogen-free flame-retardant polyamide prepared by the invention is excellent in flame retardant property, and can obtain a good flame retardant effect under different addition amounts; the limit oxygen index is basically more than 33%, the vertical combustion test reaches the UL94V-0 level, and the flame-free flame retardant is self-extinguished in the combustion test, and no molten drop is generated; the preparation method and process are simple, mild in condition and easy to operate.

The invention relates to a particulate composition comprising, or substantially consisting of, urea, an inhibitor, preferably a urease inhibitor and / or a nitrification inhibitor, and an additive, wherein the additive comprises components (i), (ii), and optionally (iii): (i) one or more polyhydric alcohols; preferably one or more carbohydrates, preferably selected from monosaccharides, disaccharides, and oligosaccharides; (ii) a first polymer, preferably an amine-containing polymer; more preferably a polyvinylamine or a polyalkyleneimine; and (ii) optionally, a second polymer, preferably a polar polymer; more preferably a water-soluble polar polymer. The invention further relates to a process for producing the particulate composition, an additive for a particulate composition, and the use of the particulate composition as a fertilizer.

The invention relates to the technical field of sewage treatment, in particular to an internal and external backflow automatic control system for sewage treatment. The system comprises an internal reflux system and an external reflux system, and the internal reflux system adjusts the frequency of internal reflux pumps or the number of started internal reflux pumps by monitoring the change of water quality parameters such as nitrate nitrogen, nitrite nitrogen, ammonia nitrogen and dissolved oxygen so as to maintain the balance of nitrification and denitrification reactions; and the external reflux system adjusts the flow of an external reflux pump by monitoring the sludge concentration and the sludge level height so as to maintain the concentration and activity of microorganisms in the biological reaction tank. Besides, the system also adopts a mathematical model, a feedforward control strategy and a feedback control module, so that the response speed and the stability of the system are improved, the effective treatment of sewage is ensured, and the overall treatment efficiency and the effluent quality are improved.

The invention belongs to the field of special chemical equipment, and particularly relates to a nitration reaction continuous separator. The device comprises an isolation cylinder, wherein a top cylinder opening of the isolation cylinder is higher than a material inlet N1 and a nitric acid inlet N2; a bottom cylinder opening of the isolation cylinder coaxially extends upwards to form a material guide cylinder, the bottom of the rotary drum coaxially extends downwards to form a small rotary cylinder, and a bottom cylinder opening of the small rotary cylinder coaxially wraps the outer wall of the material guide cylinder and is in rotary fit with the material guide cylinder; materials and nitric acid enter a primary mixing cavity formed between the outer wall of the isolation barrel and the inner wall of the shell through corresponding inlets, then are sucked into a dispersion cavity formed by a barrel cavity of the small rotary barrel through the material guide barrel, and then enter a separation cavity formed by an inner cavity of the rotary drum through communicating holes in the bottom face of the rotary drum. Nitration products separated and clarified by the rotary drum are centrifugally thrown out from a discharge hole in the top of the rotary drum, and at the moment, an area between the inner wall of the isolation barrel and the outer wall of the small rotary drum forms a reaction isolation area. According to the invention, the continuity, high efficiency and safety of nitration reaction are ensured, and the purposes of high productivity, continuous closed operation and intrinsically safe operation are achieved.

The invention relates to a process for removing nitrogen monoxide, nitrogen dioxide and nitrous oxide from an exhaust gas stream obtained in a nitration process, comprising: (a) Removing nitrogen monoxide and nitrogen dioxide from the exhaust gas stream by adding an oxygen comprising gas to the exhaust gas stream, oxidizing the nitrogen monoxide in the gas stream to form nitrogen dioxide, thereby obtaining a gas stream depleted in nitrogen monoxide; (b) Washing the gas stream depleted in nitrogen monoxide with water to obtain a gas stream depleted in nitrogen monoxide and nitrogen dioxide; (c) Converting nitrous oxide in the gas stream depleted in nitrogen monoxide and nitrogen dioxide into nitrogen and carbon dioxide and optionally oxygen in the presence of a nitrous oxide reduction catalyst and in the presence of hydrogen cyanide.

The invention provides application of 3-methyl-2-oxazolidinone as a nitrification inhibitor and a nitrification inhibition method, and relates to the technical field of soil treatment. Specifically, the invention relates to application of 3-methyl-2-oxazolidinone as a nitrification inhibitor in soil treatment and / or sewage treatment and inhibition of nitrosation activity of ammonia oxidizing bacteria. The method for inhibiting nitrification comprises the step of treating soil or water containing ammonium nitrogen and ammonia oxidizing bacteria by using 3-methyl-2-oxazolidinone. The concentration of the 3-methyl-2-oxazolidinone is not less than 0.01% w / v by taking the volume of the soil or the water body as 100%. The nitrification inhibition activity of the 3-methyl-2-oxazolidinone is found, so that the variety selection of nitrification inhibitors is enriched.

The invention discloses a composite activated carbon filter material and a preparation process thereof, and belongs to the technical field of water treatment materials. The filter material sequentially comprises a modified coconut shell activated carbon matrix, a bimetallic oxide and a biodegradable functional film from inside to outside, the modified coconut shell activated carbon matrix is prepared by a three-step process of acid leaching modification, microwave activation and nitrogen doping; the bimetallic oxide is Fe-Mn oxide nano particles; the biodegradable functional film is composed of a polyvinyl alcohol / polylactic acid blended film and a complex microbial inoculant, and the complex microbial inoculant comprises a mixed flora of pseudomonas, bacillus and nitrifying bacteria. Through the three-layer composite structure of the coconut shell activated carbon matrix, the bimetallic catalyst layer and the biodegradable film, the synergistic effect of physical adsorption, chemical catalysis and biodegradation is achieved. Through step-by-step superposition of the functional layers, the removal efficiency of complex pollutants such as organic matters, heavy metals, ammonia nitrogen and the like is remarkably improved.

The present invention discloses a pimobendan intermediate synthesis method, which comprises: 1, carrying out a Friedel-Crafts acylation reaction on a compound I and a compound A in an aprotic solvent under the effect of a Lewis acid to generate a compound II; 2, ether is used as a solvent, under the alkaline condition, the compound II and dimethyl malonate or diethyl malonate are subjected to a substitution reaction, the generated compound is subjected to a hydrolysis reaction in an aqueous alkali solution, and a compound III is generated; and 3, heating the compound III under the conditions of hydrazine hydrate and acid to generate a compound IV, namely the pimobendan intermediate. The synthesis method cancels a nitration reaction step which is high in risk and generates a large amount of waste acid water, and is short in route step and simple to operate.

Heterocyclic alkynes useful for nitrification inhibition and methods of using the heterocyclic alkynes to inhibit nitrification and increase crop yield are described.

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 a heterotrophic nitrification-aerobic denitrification bacterium resistant to high ammonia nitrogen and high organic matters and application of the heterotrophic nitrification-aerobic denitrification bacterium in landfill leachate treatment. The heterotrophic nitrification-aerobic denitrification bacterium provided by the invention is Paracoccus pantotrophus HNAD-9, the strain is preserved in the General Microbiological Culture Collection Center of the China Committee for Culture Collection of Microorganisms on August 22, 2024, and the preservation number of the strain is CGMCC No.31698. The invention further discloses a preparation method of the heterotrophic nitrification-aerobic denitrification bacterium. According to the method, ammonia nitrogen, nitrate nitrogen and nitrite nitrogen can be removed in the same heterotrophic and aerobic system at the same time, accumulation of nitrate nitrogen and nitrite nitrogen is avoided in the ammonia nitrogen removal process, and the method has important application prospects in the field of high-ammonia-nitrogen and high-organic-matter-concentration landfill leachate treatment.

The present invention provides a continuous synthesis system and synthesis method of 2-methyl-5-nitroimidazole. The system includes a raw material premixing unit, a continuous nitration unit, a continuous post-processing unit and a control unit, wherein the continuous nitration unit includes a mixing-reaction module and a gas treatment module, wherein the mixing-reaction module includes 10 to 40 longitudinally cross-arranged pipelines, wherein the angle formed between the upper and lower adjacent pipelines is 10 to 50°; the problem that the synthesis method of 2-methyl-5-nitroimidazole in the prior art is not suitable for industrialized amplification production can be solved, and the system is suitable for the field of 2-methyl-5-nitroimidazole synthesis.

The invention belongs to the technical field of waste recycling, and particularly relates to a method for recycling nitric acid in acid yellow water based on nitration. The method for recovering nitric acid based on nitration acid yellow water comprises the following steps: stirring nitration acid yellow water and toluene or nitrotoluene and other organic extraction agents in a mixer, adding a certain amount of sulfamic acid, fully extracting, standing for layering, and removing the organic extraction agents through a stripping tower to obtain the nitric acid. The acid yellow water after extraction-steam stripping is sent to a nitric acid absorption-concentration tower to obtain concentrated nitric acid, and the concentrated nitric acid is recycled to a nitration reaction unit as a raw material.

An inhibited aqueous fertilizer composition and methods of use thereof.

The utility model belongs to the technical field of sewage treatment, and relates to a sewage treatment system which comprises a first-stage anoxic tank, a first-stage aerobic tank, a second-stage anoxic tank and a second-stage aerobic tank which are sequentially connected through pipelines, and sludge generated after reaction in the second-stage aerobic tank flows back to the first-stage aerobic tank. Sludge generated after nitrification in a secondary aerobic tank in a wastewater treatment process flows back to a primary aerobic tank for cyclic nitrification, so that the chemical oxygen demand and the total nitrogen load in the sludge are reduced, and the chemical oxygen demand and the total nitrogen in discharged water are reduced; meanwhile, by arranging two-stage anoxic denitrification and two-stage nitration reaction, the nitration and denitrification reaction time is prolonged, the removal rate of ammonia nitrogen and total nitrogen in sewage is increased, the content of ammonia nitrogen and total nitrogen in drained water is reduced, the content of ammonia nitrogen, total nitrogen, chemical oxygen demand and total phosphorus in sewage is further reduced through the synergistic effect, and the emission standard is met.