1251 results about "Electrodialysis" patented technology

The invention provides a house waterproof maintenance system based on an intelligent detection and self-repairing technology, and the system comprises an intelligent sensing layer which is used for collecting multi-dimensional physical parameters of building waterproof key nodes in real time; the edge calculation analysis layer is used for performing fusion analysis and risk prediction on the perception data; the dynamic self-repairing execution layer is used for triggering a multi-stage repairing mechanism according to an analysis result; the cloud management layer is used for realizing visual management and control and strategy optimization of the whole system, and relates to the technical field of building waterproofing, the building state is monitored in real time through a multi-mode sensing network, water leakage risk prediction is realized in combination with an edge calculation algorithm, and collaborative repair of a microcapsule repair agent, a shape memory alloy grid and an electrodialysis module is triggered; the system remarkably improves the timeliness and reliability of waterproof maintenance, reduces the manual intervention cost, and is suitable for intelligent maintenance of residential buildings, industrial buildings and historical protection buildings.

The invention discloses a high-strength safety protection type electrodialyzer, and relates to the technical field of electrodialyzers, the high-strength safety protection type electrodialyzer comprises a protection frame, an electrodialyzer body is fixedly mounted in the protection frame, a rotating door is rotatably mounted on the inner wall of the protection frame, a rainproof plate is fixedly mounted on the top of the protection frame, and a heat dissipation opening is formed in the surface of the protection frame; a scraping plate is arranged on the inner wall of the heat dissipation opening; the rain and snow prevention device is arranged on the surface of the protection frame, the rain and snow prevention device comprises a supporting frame, a winding device, a linear motor, a sliding block, a fixing rod, a sliding rail, an elastic telescopic rod, a triangular block and a rotating scraping plate, the sliding block moves downwards to drive the fixing rod to move downwards, and the fixing rod moves downwards to make contact with the triangular block; the supporting frame is fixedly installed on the surface of the protection frame, a scraper blade is rotated to move downwards to scrape the filter screen, and the situation that too much dust adheres to the filter screen, the heat dissipation effect of equipment becomes poor, and normal operation of the equipment is affected is prevented.

The present invention relates to a system and a treatment method for treating high-phosphorus wastewater and resourcefully utilizing phosphorus elements. The system includes a bipolar membrane electrodialysis device, a phosphorus precipitator, and a membrane treatment device. Inside the bipolar membrane electrodialysis device, there are successively arranged a cathode, a first bipolar membrane, a main cation exchange membrane, a main anion exchange membrane, a second bipolar membrane, and an anode. Between the first bipolar membrane and the main cation exchange membrane is an alkali chamber, between the main cation exchange membrane and the main anion exchange membrane is a wastewater chamber, between the main anion exchange membrane and the second bipolar membrane is an acid chamber, the outside of the first bipolar membrane is a cathode chamber, and the outside of the second bipolar membrane is an anode chamber; the high-phosphorus wastewater is input into the wastewater chamber, the acid chamber is provided with a phosphoric acid recovery pipe, and the alkali chamber and the wastewater chamber are respectively connected to the phosphorus precipitator through an alkali liquid pipe and a first water production pipe; the phosphorus precipitator is provided with a precipitant inlet for inputting a calcium precipitant or a magnesium precipitant, the concentrated water outlet of the membrane treatment device is connected to the wastewater chamber, and the produced water of the membrane treatment device is reused as reclaimed water.

The invention discloses a method for efficiently separating and purifying plant exosomes and application, and belongs to the technical field of biological nanotechnology. The method comprises the following key steps: (1) performing sterile cleaning on plant raw materials, and then performing peeling or tissue slitting pretreatment; (2) carrying out mechanical crushing treatment by adopting a phosphate buffer solution (PBS), and filtering through a 200-mesh screen to obtain a primary extracting solution; (3) performing gradient centrifugal purification on the extracting solution, collecting supernate, and filtering the supernate through a 0.45 mu m microporous filter membrane; (4) adding 8-12% of polyethylene glycol for low-temperature phase separation and precipitation; (5) purifying by using an electrodialysis technology; and (6) carrying out final concentration by adopting a 100kDa ultrafiltration membrane to obtain the high-purity PELNs preparation. According to the method, the process, equipment and reagents are simple and easy to obtain, the final yield is high, the purity is high, particle size distribution is uniform, and an innovative solution is provided for large-scale industrial production of natural-source nano-drug carriers.

The invention discloses a method for extracting lithium from gas field produced water with a high sodium-lithium ratio, and belongs to the technical field of chemical engineering. The mass ratio of sodium to lithium in the gas field produced water is (100-1000): 1, and the method comprises the following steps: S1, nanofiltration: carrying out nanofiltration on the gas field produced water, and intercepting divalent ions to obtain nanofiltration produced water and nanofiltration concentrated water; s2, adsorbing and extracting lithium, namely adjusting the pH value of the sodium-filtered produced water, treating the sodium-filtered produced water through a lithium-sodium adsorption and separation device filled with an adsorbent to realize sodium-lithium separation, and collecting the adsorbed lithium-extracted produced water; s3, desorption of lithium ions: eluting the adsorbent with an acid solution to desorb the lithium ions from the adsorbent, and collecting an eluent; s4, concentration: carrying out reverse osmosis treatment on the eluent, and treating the reverse osmosis concentrated solution through an electrodialysis device to obtain a concentrated lithium-containing concentrated solution; and S5, lithium precipitation: adjusting the pH value of the lithium-containing concentrated solution, adding a lithium precipitation agent, and crystallizing and precipitating lithium to obtain industrial-grade lithium carbonate. The process is simple, the lithium recovery rate during lithium precipitation can be effectively increased, and full-automatic continuous operation can be achieved.

The invention relates to the technical field of coal bed gas development and gas extraction, in particular to an electrodialysis-liquid CO2 time sequence synergistic anti-reflection method and system. Comprising an electrodialysis pretreatment stage, a CO2 synergetic permeability increasing stage and a process regulation and energy recovery stage, a mixed solution is injected into a coal seam in a pulse injection mode, and energy recovery is conducted through pipeline fluid pressure in the injection stopping period. According to the technical scheme, through multi-stage cooperation of electrodialysis pretreatment, CO2 phase change fracturing and pulse consolidation and regulation, accurate transformation of the coal seam low-permeability area is achieved. According to the scheme, electrodialysis is utilized to drive an acidic working solution to target and migrate to a difficult-to-permeate area, mineral substances are dissolved, and pores are expanded; then, high-energy expansion stress is generated through liquid CO2 phase change, and a through fracture network is formed; and finally, a pulse injection and energy recovery mechanism is adopted, fracture closing is restrained, system energy consumption is reduced, and therefore the coal seam breathability and the gas extraction efficiency are integrally improved.

The utility model discloses an electrodialysis device with an automatic hydraulic station, and belongs to the field of electrodialysis devices. The hydraulic cylinder is connected with the electrodialysis assembly; an oil tank; one end of the pump body is communicated with the oil tank; the inlet end of the one-way valve is communicated with the other end of the pump body, and the outlet end of the one-way valve is communicated with the hydraulic cylinder; one end of the pressure sensor is communicated with the oil tank, and the other end of the pressure sensor is communicated between the outlet end of the one-way valve and the hydraulic cylinder; one end of the electromagnetic valve is communicated with the oil tank, and the other end of the electromagnetic valve is communicated between the outlet end of the one-way valve and the hydraulic cylinder; and the controller is electrically connected with the pressure sensor and the electromagnetic valve. The utility model has the technical effects that the pressure can be automatically controlled conveniently, and the pressure can be prevented from being too large or too small.

The invention relates to a novel composite bipolar membrane for preparing low-carbon alcohol alkali metal salt and an electrodialysis process of the novel composite bipolar membrane, and belongs to the technical field of membrane separation and electrochemical synthesis. The composite bipolar membrane comprises a cation exchange layer, a middle catalyst layer and an anion exchange layer which are sequentially laminated and compounded, the process comprises the following steps: introducing a salt solution containing alkali metal ions into an anode chamber of a bipolar membrane electrodialysis system, and introducing a low-carbon alcohol solution into a cathode chamber; applying a direct-current electric field to the two sides of the composite bipolar membrane, so that the low-carbon alcohol is dissociated at the membrane interface to generate alkoxy ions and hydrogen ions; the alkoxy ions migrate to an anode chamber to be combined with the alkali metal ions to generate low-carbon alcohol alkali metal salt; the membrane material is high in adaptability, the membrane structure is good in stability, technological parameters are mature, and the system integration degree is high.

A method for synchronously remediating organically contaminated soil and groundwater by means of electrokinetic coupled multiphase extraction. Cathode wells and anode wells are distributed in a staggered manner in an area to be remediated; a pipe filled with an electrolyte is inserted into each of the cathode wells and the anode wells; an extraction pipe is inserted into each cathode well; electrodes are connected to an electrokinetic remediation system; the extraction pipes are connected to a multiphase extraction system; by means of electrokinetic remediation, persulfate anions in a catholyte are injected into a stratum from the cathode wells and are then migrated to an anode by means of the action of electromigration, iron ions released by a sacrificial anode in an anolyte are migrated to a cathode by means of the action of electromigration and electrodialysis, and persulfate in soil and groundwater are activated during "opposite-direction" migration; then, the direction of an electric field is switched, and at the same time, electrolytes are added to corresponding electrode wells for "opposite-direction" migration, and remediation treatment is performed according to the above electrode-based remediation method and an electrode-based remediation method in which an electrode direction is switched, until organically contaminated soil and groundwater in the area to be treated are completely remediated at the same time; and the multiphase extraction system is started after the electrode-based remediation, and the electrolytes in the electrode wells are depleted. Further disclosed is the use of the method for synchronously remediating organically contaminated soil and groundwater by means of electrokinetic coupled multiphase extraction in in-situ remediation of organically contaminated soil.

According to the portable seawater desalination device provided by the scheme, a miniature magnesium air battery is used as a power supply, and a [Fe (CN6)] < 4-> / [Fe (CN6)] < 3-> redox medium is added into a cathode chamber and an anode chamber of an electrodialysis unit to form a high-concentration redox electrolyte, so that the current density and the ion migration rate are improved. A magnesium electrode is adopted as an anode and cooperates with a miniature magnesium air battery, the electrochemical environment is optimized, efficient and high-water-recovery-rate seawater desalination is achieved, seawater can be stably desalted into fresh water (TDS is smaller than or equal to 1000 mg / L) meeting the drinking water standard, and the seawater desalination device is suitable for outdoor exploration, emergency and other scenes.

The invention relates to a method of preparing a lactose-reduced milk product by e.g. ultrafiltration which method involves recovery of at least some of the mineral from the ultrafiltration permeate by electrodialysis.

The invention relates to the technical field of water pollution control and treatment, and particularly discloses a method for deeply treating wastewater based on an adsorbent, which comprises the following steps of: firstly, introducing a mixed gas of carbon dioxide and air into fly ash water washing liquid, and removing calcium ions in the water washing liquid in a calcium carbonate precipitation form in a continuous introducing process; interference of calcium ions on adsorption and electrodialysis processes in the subsequent treatment process is avoided, heavy metals in the water washing liquid are accurately adsorbed and removed while the iron-sulfur loaded magnetic mesoporous biochar is used for activating efficient oxidation of persulfate, finally, electrodialysis treatment is performed on the water washing liquid by using a self-made bipolar membrane, chlorine in water is taken out, and the heavy metals in the water washing liquid are removed. And the washing liquid can meet the requirement of wastewater discharge.

The application discloses a bipolar membrane electrodialysis device, which comprises an outer box body and further comprises a liquid inlet mechanism, a plurality of electrodialysis mechanisms and a plurality of filtering mechanisms. The filtering mechanism comprises a filtering box, a driving filtering assembly and a liquid feeding assembly. The driving filtering assembly comprises a motor installed on the top of the filtering box, the output shaft of the motor is fixedly connected with a threaded rod, the outer periphery of the threaded rod is threadedly connected with a filtering plate slidingly connected to the inner wall of the filtering box, and the bottom inner wall of the filtering box is fixedly connected with a plurality of plug rods matched with filtering holes of the filtering plate. Raw water is delivered to the inside of the filtering box through the liquid inlet mechanism, is actively filtered without turbulence through the driving filtering assembly, is delivered to the corresponding electrodialysis mechanism through the liquid feeding assembly and is further subjected to electrodialysis treatment. The filtering plate and other components are arranged to filter out the solid impurities mixed in industrial glucose acid salt, so that the bipolar membrane electrodialysis process and the bipolar membrane body are not affected.

The invention relates to the field of functional nutritional seasonings, and particularly discloses an abalone umami peptide prepared from an abalone cooking waste liquid and a preparation method thereof, and the preparation method comprises the following steps: (1) removing solid impurities from the abalone cooking waste liquid, and removing heavy metals by using electrodialysis; (2) adding the material obtained in the step (1) into specific protease accounting for 0.1-1% of the weight of the solid in the material obtained in the step (1), and carrying out an enzymolysis reaction under the conditions that the enzymolysis pH value is 6-7, the reaction temperature is 40-60 DEG C and the reaction time is 0.5-2 hours; and 3) removing impurities by using a nanofiltration membrane, and carrying out spray drying to obtain the abalone umami peptide. According to the abalone flavor peptide prepared by the method, the problem of environmental pollution caused by a large amount of abalone cooking waste liquid is solved, waste is turned into wealth, and a new way of resource utilization of the abalone cooking waste liquid is realized. The ratio gt of the molecular weight of the abalone umami peptide is 1-2KD; the seafood seasoning not only is high in antioxidant biological activity and low in heavy metal content, but also has rich seafood flavor, and can be widely applied to the field of functional nutritional seasonings.

The invention belongs to the technical field of green processing of biomass materials, and particularly relates to a green preparation process of high-deacetylation-degree chitin. The preparation method aims at the problem of high energy consumption of existing high-deacetylation-degree chitin preparation. According to the method, raw materials are pretreated by utilizing a compound enzyme system under a low-temperature condition, chitin crystal lattices are preliminarily dissociated by combining a deep eutectic solvent at a medium temperature, high deacetylation conversion is realized through short-time dissolution of an ionic liquid, and meanwhile, a membrane separation-electrodialysis-gradient freezing crystallization three-stage recycling technology is matched, so that recycling of the solvent is realized; the method greatly reduces the reaction temperature and energy consumption, avoids the use of corrosive reagents, and has the advantages of environmental protection, low energy consumption, high deacetylation degree of the product, excellent quality and the like.

The invention relates to a method for simultaneously preparing lithium hydroxide and sulfuric acid. The invention provides a method for simultaneously preparing lithium hydroxide and sulfuric acid, which comprises the following steps: preparing a bipolar membrane electrodialysis device which comprises a first bipolar membrane, an anion exchange membrane, a cation exchange membrane and a second bipolar membrane, and forming an acid chamber between the first bipolar membrane and the anion exchange membrane, a salt chamber is formed between the anion exchange membrane and the cation exchange membrane, and an alkali chamber is formed between the cation exchange membrane and the second bipolar membrane; a lithium sulfate aqueous solution is added into a salt chamber of the bipolar membrane electrodialysis device, a sulfuric acid aqueous solution is added into an acid chamber, and a lithium hydroxide aqueous solution is added into an alkali chamber; and discharging the desalted solution formed in the salt chamber of the bipolar membrane electrodialysis device, discharging the sulfuric acid aqueous solution formed in the acid chamber, and discharging the lithium hydroxide aqueous solution formed in the alkali chamber.

The invention relates to the technical field of electrochemical water treatment, and discloses a high-salt waste liquid electric flocculation hardness removal and electrodialysis resourceful treatment method and a high-salt waste liquid electric flocculation hardness removal and electrodialysis resourceful treatment system. The method comprises the following steps: collecting water quality parameters of the high-salt waste liquid and initial electrochemical impedance spectroscopy parameters of a polar plate; calculating the initial current density according to the hardness and the conductivity, carrying out electric flocculation treatment, monitoring impedance spectrum change in real time, identifying the scaling type, and predicting the residual operation time of the polar plate; the current density is optimized according to the prediction time, and the residual hardness is calculated; and adjusting electrodialysis parameters by taking the residual hardness as a feedforward signal for concentration, and performing bipolar membrane electrodialysis on the concentrated solution to obtain acid-alkali liquor. The problems that in the electrochemical treatment process of the high-salt waste liquid, the state of a polar plate cannot be monitored in real time, consequently, operation parameters are adjusted blindly, and energy consumption is high and the recycling efficiency is low due to the fact that parameters of a pretreatment unit and parameters of a pretreatment unit are not linked are solved.

To provide a method for yielding a lithium-containing liquid suitable as a raw material for producing lithium compounds of high purity, from to-be-treated water containing lithium ions, sodium ions, metal ions other than lithium ions and sodium ions, fluoride ions, and anions serving as conjugate bases of acids, and to provide related techniques thereof.SOLUTION: Provided is a method for producing a raw material liquid for a lithium compound, comprising: step 1 of adding a sulfiding agent and a calcium compound to the to-be-treated water, subjecting the to-be-treated water containing the formed solid matter to solid-liquid separation to obtain a treated liquid A; step 2 of adding an oxalate ion source to the treated liquid A, subjecting the treated liquid A containing the formed solid matter to solid-liquid separation to obtain a treated liquid B; and step 3 of subjecting the treated liquid B to bipolar electrodialysis to obtain an alkaline liquid containing lithium ions and sodium ions as a raw material liquid for producing a lithium compound.SELECTED DRAWING: None

The present application relates to the field of functional nutritional condiment, and specifically discloses abalone umami peptide prepared by using abalone cooking waste liquid as raw material and a preparation method thereof, which comprises the following steps: (1) removing solid impurities from the abalone cooking waste liquid and removing heavy metals by electrodialysis; (2) adding specific protease to the material obtained in step (1) at a dosage of 0.1-1% of the weight of the solid content in the material obtained in step (1), and performing enzymatic reaction at a pH value of 6-7 and a reaction temperature of 40-60 DEG C for 0.5-2 h; (3) removing impurities by using nanofiltration membrane and performing spray drying to obtain abalone umami peptide. The abalone umami peptide prepared by the method solves the problem of environmental pollution caused by a large amount of abalone cooking waste liquid, and realizes a new way of resource utilization of abalone cooking waste liquid. The abalone umami peptide has a molecular weight of 1-2 KD and accounts for more than 70%, has high antioxidant bioactivity, low heavy metal content, and rich seafood flavor, and can be widely applied in the field of functional nutritional condiment.

Provided is a cation exchange membrane in which when a hydroxide aqueous solution showing strong alkalinity is produced by using an electrodialyzer, significant swelling in the cation exchange membrane in contact with the hydroxide aqueous solution is suppressed, destruction of a cation exchange resin due to polyvalent cations contained as impurities in a raw material inorganic salt is suppressed, and the capacity of the cation exchange membrane is hardly lowered.　This cation exchange membrane is characterized by having an electric resistance of 2.0-5.0 (Ω∙cm2), as measured at 25ºC in 0.5 mol / L of a NaCl aqueous solution, and a dimensional change rate of at most 1.2%.

The invention relates to a method for extracting lithium from a salt lake and synchronously removing silicon and boron. The method comprises the following steps: pre-treating and filtering lithium-containing brine; carrying out reverse osmosis concentration treatment to concentrate lithium to be more than 2.5 g / L; carrying out nanofiltration treatment to remove magnesium, calcium and sulfate ions; treating by adopting an electrodialysis system to obtain a high-silicon and high-boron desalted solution and a low-silicon and low-boron lithium concentrated solution; the low-silicon and low-boron lithium concentrated solution is treated with chelating resin and boron removal resin, so that magnesium and calcium ions are smaller than or equal to 2 mg / L, boron is smaller than or equal to 20 mg / L, and the refined lithium concentrated solution is obtained; concentrating by an evaporation system, adding a precipitant, precipitating, filtering, washing, crushing and demagnetizing to obtain a low-silicon low-boron battery-grade lithium carbonate product. The invention further discloses a system for extracting lithium from the salt lake and synchronously removing silicon and boron, the complex and low-efficiency boron removal and silicon removal nanofiltration process is adopted, and concentration of lithium and efficient removal of silicon and boron are synchronously achieved; silicon scaling pollution caused by membrane separation and heat exchanger tube nests is avoided, and deep removal of silicon and boron is realized.

The invention discloses a method for converting lithium hydroxide into lithium carbonate. The method comprises the following steps: S1, preparing or taking a lithium hydroxide solution and a carbonate solution; s2, putting the lithium hydroxide solution and the carbonate solution into electrodialysis equipment, and carrying out electrodialysis treatment; and S3, after electrodialysis is finished, collecting a lithium carbonate solution, and sequentially carrying out lithium precipitation and solid-liquid separation on the lithium carbonate solution to obtain the battery-grade lithium carbonate. According to the method for converting lithium hydroxide into lithium carbonate disclosed by the invention, CO2 is replaced by carbonate, so that the generation of lithium bicarbonate is avoided, the lithium carbonate and the byproduct alkali liquor are directly obtained, the raw material source is wide, the preparation condition is mild, the production cost is greatly reduced, and the method has huge potential economic benefits.

A system and process for the capture of carbon dioxide from a gaseous feedstock, regenerating carbon dioxide in a purified form, and regenerating reagents, wherein the reagent regeneration having reduced energy consumption in relation to carbon dioxide capture. Carbon dioxide captured by a slurry scrubbing solution producing a resultant product that can be reacted with an acid reagent to form the regenerated carbon dioxide and a resultant salt solution. Electrodialysis with bipolar membrane separation employed on the resultant salt solution to form regenerated acid and regenerated base. The regenerated base recirculated as the scrubbing solution to capture additional carbon dioxide, and the regenerated acid recirculated for additional acid reaction with additional resultant product, such that the system and process can continuously capture and form regenerated carbon dioxide in a purified form compared to the carbon dioxide of the gaseous feedstock.

The invention belongs to the technical field of impurity separation, and particularly discloses a method for separating and purifying impurities in a process for preparing glyoxylic acid through oxalic acid electrolysis, a crystallization kettle is included, an isolation device is arranged in the crystallization kettle, and the isolation device comprises a conical top cover, a conveying pipe, an annular filter screen, a directional conveying assembly and a sealing assembly; the conical top cover is arranged at the axis of the crystallization kettle, an opening of the conical top cover faces downwards, and a plurality of fixing rods are fixedly connected between the top of the conical top cover and the inner wall of the side face of the crystallization kettle. According to the method, glyoxylic acid product solutions with different concentration specifications and the high-purity glyoxylic acid crystal can be obtained after the electrolyte is sequentially subjected to pre-evaporation, electrodialysis, secondary evaporation, cooling crystallization, solid-liquid separation, washing and drying and other procedures, so that the prepared high-purity glyoxylic acid crystal can be popularized and applied in the field of high-end medicine.

The utility model provides a vacuum concealed pipe circulating water salt elimination system which comprises a plurality of concealed pipes which are respectively connected with a water conveying pipe through a water collecting pipe; the concealed pipe comprises a pipe body, and a plurality of water collecting holes are formed in the pipe body; each water collecting pipe is provided with a vacuum negative-pressure drainage device, the water conveying pipe is connected with a salt washing water treatment device, and the water conveying pipe is provided with a water suction pump; a water outlet pipe is further connected to the salt washing water treatment device, and the water outlet pipe is connected with an irrigation leaching water distribution device used for leaching soil; the washing brine treatment device comprises an electrodialysis treatment unit, the front end of the electrodialysis treatment unit is connected with a reservoir, the rear end is connected with a fresh water tank, and a flowmeter is arranged on a pipeline for connecting the electrodialysis treatment unit and the reservoir; the fresh water pool is connected with the water outlet pipe, the reservoir is connected with the water pipe, the fresh water pool is further provided with an overflow pipe, and a drainage port end of the overflow pipe extends to the drainage ditch. According to the invention, the salt elimination efficiency is greatly improved, the investment cost of concealed pipe laying is reduced, the water is saved, and water pollution is prevented.

The invention discloses a method for preparing high-modulus sodium silicate and co-producing white carbon black from rice hull ash. The method comprises the following steps: crushing the rice hull ash, and acidizing to obtain purified rice hull ash powder; reacting the purified rice hull ash powder with 5wt%-15wt% of caustic soda generated by bipolar membrane electrolysis to prepare a sodium silicate solution; carrying out neutralization reaction on the sodium silicate solution and 1-15 wt% of sulfuric acid solution under the assistance of ultrasonic waves, and filtering to obtain silicon dioxide silica gel and filtrate; washing and drying the silicon dioxide silica gel to obtain a white carbon black product; and carrying out electrolytic treatment on the filtrate through a bipolar membrane electrodialysis system, and respectively recycling the recovered alkali liquor and acid liquor. According to the method, resource utilization of the rice hull ash and cyclic regeneration of the reaction medium are realized, and a green production process is formed.

The invention relates to a method for separating and purifying a liquid system, the liquid system comprises an ionic liquid with the concentration ranging from 0.05 mol / L to 6.0 mol / L and a metal salt with the concentration ratio of the ionic liquid to the metal salt ranging from 2: 1 to 1: 2, and the method comprises the following steps: carrying out first-stage electrodialysis on the liquid system at the first current density ranging from 0.1 mA / cm < 2 > to 50 mA / cm < 2 >, and carrying out second-stage electrodialysis on the liquid system at the second current density ranging from 0.1 mA / cm < 2 > to 50 mA / cm < 2 >; an ionic liquid primary product and a metal salt primary product are obtained; evaporating the ionic liquid primary product and the metal salt primary product to obtain an ionic liquid concentrated solution and a metal salt concentrated solution; and performing second-stage electrodialysis on the ionic liquid concentrated solution and the metal salt concentrated solution at a second current density of 0.1-50mA / cm < 2 > to obtain an ionic liquid product and a metal salt product. According to the method disclosed by the invention, all process links are properly joined and organically coupled, and the method is operated at normal temperature and normal pressure, has relatively high production efficiency, is easy for large-scale development, is an additive-free, basically secondary-waste-free and green method, and has industrial application value.

The invention relates to a lithium ion conductive dense membrane and a preparation method and application thereof. The lithium ion conductive dense membrane comprises a polymer base membrane, ion conductive inorganic particles and a polymer solid electrolyte, the polymer base membrane is of a net structure; the Gurley value of the lithium ion conductive dense film is larger than or equal to 1000, and the porosity is smaller than or equal to 5%. The lithium ion conductive dense membrane provided by the invention has the advantages of high lithium ion conductivity, high transport efficiency and high lithium ion selectivity, and can be applied to electrodialysis lithium extraction. And under the action of external voltage, lithium ions are directionally migrated to the air negative electrode subjected to oxygen reduction reaction through the lithium ion conductive dense membrane to form a lithium hydroxide solution, and other metal hetero-ions are isolated on the positive electrode side by the lithium ion conductive dense membrane, so that lithium enrichment is realized. And meanwhile, transportation of the membrane to lithium ions does not depend on pores in the conductive membrane, so that the service life can be prolonged while the lithium ion separability and the transportation efficiency of the salt lake lithium extraction method are improved.

An electrochemical apparatus comprising: an anode; a bipolar membrane; an anion exchange membrane; a cation exchange membrane; and a cathode; wherein: the anode at least partially defines a first fluid flow path; the anode and / or the first fluid flow path is in contact with the anion exchange membrane of the bipolar membrane; a second fluid flow path is defined between the cation exchange membrane of the bipolar membrane and the anion exchange membrane; a third fluid flow path is defined between the anion exchange membrane and the cation exchange membrane; the cathode at least partially defines a fourth fluid flow path; and the cation exchange membrane is in contact with the cathode and / or the fourth fluid flow path.

The invention provides a method for recovering lithium phosphate from a lithium iron phosphate positive electrode material, which comprises the following steps: carrying out oxidation leaching on the lithium iron phosphate positive electrode material by using an acid solution and an oxidizing agent to obtain a first leaching solution and a first leaching residue; after water is added into the first leaching residues for size mixing, alkali leaching is conducted through sodium hydroxide, second leaching liquid and iron / carbon insoluble residues are obtained, and sodium phosphate crystals are obtained after the second leaching liquid is condensed; carrying out lithium precipitation reaction on the first leaching solution by using the sodium phosphate crystal to obtain lithium phosphate and lithium precipitation residual liquid; the lithium precipitation residual liquid is subjected to concentration and impurity removal, and then is subjected to a bipolar membrane electrodialysis process to obtain an acid solution and sodium hydroxide for reutilization. The invention aims to provide a method for mutually separating lithium, iron and phosphorus aiming at the waste lithium iron phosphate positive electrode material, the method can almost completely recover lithium, iron and phosphorus in the lithium iron phosphate positive electrode material, and the lithium is high in recovery rate and high in purity.