139results about How to "High ion selectivity" patented technology

This redox flow secondary battery has an electrolyte tank (6) containing: a positive electrode cell chamber (2) containing a positive electrode (1) comprising a carbon electrode; a negative electrode cell chamber (4) containing a negative electrode (3) comprising a carbon electrode; and an electrolyte membrane (5) as a barrier membrane that separates/isolates the positive electrode cell chamber (2) and the negative electrode cell chamber (4). The positive electrode cell chamber (2) contains a positive electrode electrolyte containing an active substance, the negative electrode cell chamber (4) contains a negative electrode electrolyte containing an active substance, and the redox flow secondary battery charges and discharges on the basis of the change in valency of the active substances in the electrolytes. The electrolyte membrane (5) contains an ion exchange resin composition that is primarily a polyelectrolyte polymer, and the electrolyte membrane (5) has a reinforcing material comprising a fluorine-based porous membrane.

The invention relates to an anion chromatographic column a preparation method thereof, particularly relates to a preparation method of a surface-grafting anion chromatography stationary phase. The method disclosed herein is characterized by: preparing monodispersed linear polystyrene microspheres seeds by dispersion polymerization, activating the seeds, then synthesizing polystyrene-divinyl benzene-glycidyl methacrylate microballoons by one-step seed swelling method, and extracting to remove the pore forming agent; adopting multi-step grafting synthetic method, taking methylamine and 1,4-butanediol diglycidyl ether as raw materials, and introducing a large amount of positively charged quaternary ammonium groups as the anion exchange functional group to the surface of the prepared polystyrene-divinyl benzene-glycidyl methacrylate microballoons; and packing by homogenate method. According to the invention, the method disclosed herein has the advantages of low cost and simple process, the prepared filling material has uniform granularity and has no need to be screened, and the particle size distribution is narrow.

The invention provides a preparation method of a two-dimensional/one-dimensional heterogeneous nanochannel film. The method is characterized by comprising the following steps that step 1, graphene oxide is dissolved in an aqueous piperazine solution, and ultrasonic treatment is performed at the room temperature to obtain a uniformly dispersed first solution; step 2, the first solution is added dropwise to the upper layer of a porous aluminum oxide film, and after the solvent is evaporated at the room temperature, a first composite film with a graphene oxide film layer and a porous aluminum oxide film layer is obtained; step 3, a benzenetricarbonyl trichloride solution is added dropwise to the upper surface of the graphene oxide film layer of the first composite film, and drying is carriedout to obtain the two-dimensional/one-dimensional heterogeneous nanochannel film. The invention provides the two-dimensional/one-dimensional heterogeneous nanochannel film prepared by using the methodand application of the two-dimensional/one-dimensional heterogeneous nanochannel film in salt difference energy conversion.

The invention relates to the field of alkaline redox flow battery energy storage, in particular to a preparation method of an ion exchange membrane for an alkaline redox flow battery, which is mainlyused for solving the problem of the high price of a Nafion diaphragm in the alkaline redox flow battery at the present stage, so that the cost of the redox flow battery is greatly reduced. An alkalineaqueous solution of ferricyanide (such as Na3[Fe(CN)6], K3[Fe(CN)6], (NH4)3[Fe(CN)6] and the like) is used as a positive electrolyte, and a strong alkaline solution (such as KOH, NaOH and the like) is used as a negative electrolyte; graphite felt and carbon felt are selected as positive electrode materials, and a zinc plate is selected as a negative electrode material; and the ionized sulfonatedpolyether ether ketone (SPEEK) diaphragm is used as an ion exchange membrane to assemble the battery. Therefore, the alkaline redox flow battery system with low cost and high performance is obtained.The flow battery system provided by the invention has the advantages of the high open-circuit voltage, the low cost, the high efficiency, the good cycling stability, safety, reliability and the like,and has a wide application prospect.

The invention provides an arsenic-removing adsorbent for drinking water and a preparation method thereof. The adsorbent contains composite metal oxide and a polymer material binder. The arsenic-removing adsorbent has high adsorption property, high adsorption selectivity on arsenic in the drinking water, and high adsorption capacity; adsorbent particles have high strength in a dry state or in a moist state, and the adsorbent has low breakage rate of the particles and cannot be dissolved out during use; and the adsorbent is used under the conditions of long time and larger change of waterflow pressure.

The invention provides an arsenic removal adsorbent and a preparation method thereof. The adsorbent contains sulfate akaganeite and high-molecular material agglomerant. In the invention, the particles of the arsenic removal adsorbent have high adsorption property to have high adsorption selectivity to arsenic in drinking water, the adsorption capacity is high, the adsorbed particles have large strength under a drying state or a moisture state, the particle crushing rate is low during use, no adsorbent is dissolved out, and the arsenic removal adsorbent is suitable for being used for a long time and under the condition of larger water flow pressure change.

The invention relates to a liquid flow cell composite membrane and application thereof in liquid flow cells, a pore membrane prepared from raw materials of one or two or more kinds of organic polymer resin is used as a matrix, one side surface of the matrix is composited with a dense membrane prepared from cation exchange resin, and the composite membrane is simple in preparation method and environmental friendly in process. Compared with the original pore membrane, the composite membrane has higher hydrophily and ionic selectivity, and can effectively inhibit the electrolyte solution migration problem, and the type and use scope of the liquid flow cell pore membrane material can be expanded.

A method of operating a redox flow battery, may include maintaining a positive electrode compartment pressure greater than a negative electrode compartment pressure, and maintaining a cross-over pressure less than a membrane break-through pressure, wherein the cross-over pressure equals the negative electrode compartment pressure subtracted from the positive electrode compartment pressure. In this way, ionic resistance across the separator can be maintained at a lower level by reducing gas bubbles trapped therein while reducing separator break-through, thereby increasing performance of the redox flow battery system.

The invention discloses an application of a porous membrane in an alkaline zinc-iron flow battery. The porous membrane is a porous conductive membrane prepared from one, two or more organic polymer resin as a raw material with a phase conversion method. The porous conductive membrane has the membrane pore size of 1-10 nm and porosity of 40%-70%. The porous conductive membrane has higher ion selectivity and can effectively solve the migration problem of electrolyte solutions, prolong the cycle life of the battery and improve the performance of the battery, and meanwhile, the production cost ofmembrane materials of flow energy storage batteries is substantially reduced.

The purpose of the present invention is to provide a redox flow secondary battery which has low electrical resistance and excellent current efficiency in addition to durability. The present invention relates to: an electrolyte membrane for redox flow secondary batteries, which contains an ion exchange resin composition containing a fluorine-based polymer electrolyte; and a redox flow secondary battery which uses the electrolyte membrane for redox flow secondary batteries.

The invention discloses a preparation method of an amphoteric functional PEEK (polyetheretherketone) ion exchange membrane, and particularly relates to a preparation method of an ion exchange membrane having high ion selectivity and used for a VFB (vanadium flow battery). Side chains of a membrane material contain amphoteric functional groups. The preparation method comprises steps as follows: 1) preparation of sodium imidazolate; 2) halomethylation of PEEK; 3) imidazole modification of PEEK; 4) bifunctionalization of PEEK. The amphoteric functional groups are introduced into the ion exchange membrane, the vanadium resisting capability of the membrane is improved by use of the Donnan effect of electropositive groups, proton conduction can be guaranteed through contained sulfonate radical, and the ion exchange membrane having high ion selectivity is obtained. The preparation process is simple and low in cost, and the prepared amphoteric ion exchange membrane has high ion selectivity and is suitable for being applied to the VFB.

The invention relates to a preparation method of an ion exchange membrane and an application thereof, belongs to the technical field of ion exchange membrane preparation process, and mainly solves thetechnical problems of low ion conductivity, poor mechanical stability and the like existing in the present ion exchange membrane. The technical scheme of the invention is as follows: the preparationmethod of the ion exchange membrane comprises the following steps: 1) dissolving a perfluorosulfonic acid resin in a high boiling point polar solvent to prepare a perfluorosulfonic acid resin solution; 2) coating the perfluorosulfonic acid resin solution on a clean polytetrafluoroethylene porous mesh cloth through casting, dipping or scraper to prepare a mesh cloth supported perfluorosulfonic acidmembrane; and 3) soaking the mesh cloth supported perfluorosulfonic acid membrane in the nitrogen-containing heterocyclic polymer resin solution, then thoroughly drying the membrane, rinsing with water for many times and drying the membrane so as to obtain the ion exchange membrane. The preparation method has the advantages of high ion selectivity, high mechanical and chemical stability and the like.

The invention discloses a high-selectivity self-microporous polyamide nanofiltration composite membrane and a preparation method thereof. The composite membrane is formed by compounding an ultrafiltration base membrane and a polyamide separation layer, wherein the polyamide separation layer is formed by polymerizing a water-phase mixed amine solution and an organic acyl chloride solution on the surface of the ultrafiltration base membrane, the water-phase mixed amine solution is a mixed solution of organic amine and an amine monomer which contains a sulfonic acid quaternary ammonium salt group and has a rigid twisted structure; the ultrafiltration base membrane can also adopt a surface hydrophilic modified ultrafiltration base membrane, and the polyamide separation layer is polymerized on the surface of the hydrophilic modified ultrafiltration base membrane in an in-situ support-free interface polymerization mode, so that the ultrathin high-selectivity self-microporous polyamide nanofiltration composite membrane can be obtained. The high-selectivity self-microporous nanofiltration membrane is prepared by introducing a novel amine monomer which contains a sulfonic acid quaternary ammonium salt group and has a rigid twisted structure, and the problems that an existing self-microporous nanofiltration membrane is relatively hydrophobic, so that the flux is low, the selectivity is insufficient, the pollution resistance is poor due to large membrane surface roughness and the like can be solved.

The invention relates to the ion exchange film field and particularly relates to a multilayer composite proton exchange film containing perfluorosulfonic acid resin and a preparation method thereof. The perfluorosulfonic acid resin is dissolved in corresponding solvent to form preparation liquid having a certain concentration, a film is formed through scraping under the certain temperature and atmosphere, the solvent is volatilized into a film, the perfluorosulfonic acid resin film is taken as a perfluorosulfonic acid resin base film, an inorganic functional layer is prepared on the surface thereof through the hydrothermal method, and the composite proton exchange film is finally obtained. The method is advantaged in that a problem of low ion selectivity of a conventional perfluorosulfonicacid film is solved through the composite inorganic functional layer, moreover, mechanical properties of the composite film are significantly improved, produced products have better performance thancommercially available products, the cost is lower than similar products, and the method is of great significance for wider application of ion exchange films.

The invention discloses a proton-conducting membrane for flow batteries and a preparation method thereof. The method comprises the following steps: chloromethylating polymers (such as polysulfone, polyphenyl ether and other engineering plastics) with excellent heat stability and chemical stability, grafting a molecule containing functional tertiary amino group to obtain a tertiary-amino ion-conducting membrane, and carrying out flow casting or solution coating to obtain the membrane. The prepared membrane is compact, homogeneous and transparent, has excellent proton conductivity, ionic selectivity and chemical stability, and can satisfy the application requirements of all-vanadium redox flow batteries. The polymer ion-conducting membrane can also be used as a diaphragm material for proton exchange membrane fuel batteries, water electrolyzers, supercapacitors and other devices. The membrane has the advantages of simple preparation method, environment-friendly technique, low cost and excellent mechanical properties.