1035 results about "Interfacial polymerization" patented technology

The invention discloses a p-type or n-type COF film, the film thickness is 50 nm to 5 m, the aperture is 0.7 nm to 4 nm, and the film has a regular pore channel structure and light response performance. According to the invention, proper monomers are selected, and liquid-solid interface polymerization reaction is carried out, so that COF membranes grow along the tube wall, and p-type and n-type COF membranes are respectively prepared. The growth direction of the film is inconsistent with the transmission direction of the monomer and the catalyst, and the process can effectively promote the dissolution growth and self-repair of the COF film, so that the crystallinity and stacking orientation of the film are improved, and the structural characteristics of the COF film are optimized. The obtained COF film has a remarkable advantage of light-driven ion pump performance. The obtained COF membrane is used for preparing a desalting device.

The invention provides a PVDF (Polyvinylidene Fluoride) nanofiltration membrane constructed on the basis of microwave-enhanced bridging interfacial polymerization as well as a preparation method and application of the PVDF nanofiltration membrane. The method comprises the following steps: reacting PVDF powder with an organic alkali to prepare a modified film-forming solution, blade-coating the modified film-forming solution on a non-woven fabric supporting layer, placing the non-woven fabric supporting layer in an ethanol-water or methanol-water coagulating bath, and preparing a PVDF supporting film by virtue of assistance of an ice template; weighing the functionalized nano material and an amino silane coupling agent, performing ultrasonic dispersion, and adding a catalyst for reaction to obtain dispersion liquid; immersing a PVDF support membrane into the dispersion liquid to obtain a modified membrane; immersing the modified membrane into an aqueous solution containing an amine monomer and an organic solution containing an acyl chloride monomer, and carrying out microwave radiation. The interface reaction rate and selectivity are enhanced through the microwave excitation effect, and meanwhile, the hydrophilicity and reaction activity of the PVDF base membrane are cooperatively regulated and controlled, so that the separation efficiency and the anti-pollution capacity of the membrane are remarkably improved. The obtained PVDF nanofiltration membrane has high flux, high selectivity and excellent structural stability, and is suitable for efficient purification and resource recovery application in a complex water system.

The invention discloses a desalting membrane as well as a preparation method and application thereof, and relates to the technical field of membrane separation. The desalting membrane comprises a porous ultrafiltration base membrane and a functional layer formed on the surface of the porous ultrafiltration base membrane; the functional layer is formed by copolymerizing and cross-linking a polyamine monomer, a zwitterionic multi-element hydroxyl monomer and an acyl chloride monomer through an interfacial polymerization reaction. The preparation method comprises the following steps: providing the porous ultrafiltration base membrane; coating the surface of the porous ultrafiltration base membrane with an alkaline water-phase solution containing a polyamine monomer and a zwitterionic multi-hydroxyl monomer to form a water-phase solution layer; coating an oil-phase solution containing an acyl chloride monomer on the surface of the water-phase solution layer to form a functional layer; and performing heat treatment. The invention also provides application of the desalination membrane in any one of seawater desalination, brackish water desalination, wastewater treatment and material separation and concentration. According to the invention, zwitter-ion-based multi-hydroxyl monomers are introduced into water-phase monomers to participate in interfacial polymerization, and a super-hydrophilic nano-channel is constructed in a separation layer, so that the water flux and the desalination rate of the membrane are remarkably improved.

The invention discloses a preparation method of a photocatalytic nanofiltration membrane based on IL-GQDs. The method comprises the following steps: pretreating bagasse, and applying the pretreated bagasse and imidazole ionic liquid (IL) to preparation of ionic liquid functionalized graphene quantum dots (IL-GQDs); the IL-GQDs are uniformly distributed on the surface of the base membrane by utilizing a vacuum-assisted low-temperature interfacial polymerization technology to form an ultrathin photocatalytic active layer; and finally, curing and cleaning to obtain the photocatalytic nanofiltration membrane based on the IL-GQDs. According to the prepared IL-GQDs, the membrane surface is endowed with high specific surface area and excellent photocatalytic activity, and meanwhile, an additional water transmission channel can be established under the condition that the pore diameter of the membrane is not changed, so that the problem of trade-off of a traditional membrane is solved. In addition, through combination of low-temperature and vacuum-assisted interfacial polymerization technologies, the membrane structure is more uniform and compact, defects on the surface of the membrane are reduced, and the stability and the anti-pollution capacity of the membrane are improved. The membrane disclosed by the invention shows relatively high water flux, salt recovery rate and long-term stability in water treatment application.

The invention discloses a preparation method of an acid-resistant polyquaternary ammonium membrane based on a Porxitch interfacial polymerization reaction. The preparation method comprises the following steps: dissolving an amine monomer in a water-phase solvent to form a water-phase solution; dissolving a bromomethyl monomer in an organic phase solvent to form an organic phase solution; after the base membrane is soaked in the water phase solution for a period of time, the water phase solution is removed, and the water phase solution remaining on the surface of the base membrane is removed; coating the organic phase solution on the surface of a base membrane, and carrying out interfacial polymerization reaction for 1-15 minutes at the high temperature of 50-90 DEG C, so as to prepare a polyquaternary ammonium membrane on the base membrane; and washing the surface of the polyquaternary ammonium membrane with an organic solvent to remove residual reactants, and then carrying out heat treatment in a drying oven to obtain the acid-resistant polyquaternary ammonium membrane.

The invention provides a high-flux chlorine-resistant anti-pollution composite nanofiltration membrane and a preparation method and application thereof, and the preparation method comprises the following steps: immersing a porous base membrane into a water-phase monomer solution, taking out the porous base membrane, removing a surface solution, and immersing the porous base membrane into an organic-phase monomer solution to complete interfacial polymerization to obtain an initial polyamide active layer; immersing the prepared initial polyamide active layer in a mixed solution containing sodium lignin sulfonate, a surfactant and a catalyst to complete surface modification; and carrying out thermocuring on the prepared surface-modified polyamide active layer to obtain the high-flux chlorine-resistant anti-pollution composite nanofiltration membrane. The anti-pollution performance and water flux of the prepared composite nanofiltration membrane are obviously improved, the composite nanofiltration membrane is suitable for being used as drinking water terminal treatment, and softening and purification of drinking water are achieved.

The invention provides a polyimide multilayer composite membrane material as well as a preparation method and application thereof, and belongs to the technical field of gas separation. According to the method, through collaborative design of a functional support layer, a gradient MOF layer and an ultrathin selection layer structure, the problems of support layer pore seepage, MOF agglomeration, weak interface bonding and the like in an existing composite membrane material are solved. The preparation method comprises the following steps: firstly, carrying out electrostatic spinning on a polyamide acid glue solution, and synchronously introducing dopamine by adopting a chemical imidization method to prepare a functionalized polyimide fiber membrane containing hydroxyl and amino on the surface, so that the mechanical property of a supporting layer and the MOF anchoring capability are remarkably improved; growing MOF layers with different particle sizes on the surface of the fiber membrane by regulating and controlling the concentration gradient of ligand / metal salt and the reaction time, and passivating through a silane coupling agent after each step of growth so as to avoid heterogeneous nucleation and construct a gradient structure; after the MOF gradient layer is subjected to Ar plasma pretreatment to introduce hydroxyl, the ultrathin polyamide selection layer is formed by utilizing interfacial polymerization of fluorine-containing acyl chloride and a macrocyclic amine monomer, and the ultrathin polyamide selection layer is suitable for gas separation work.

The invention discloses a surface-enhanced tryptophan modified nanofiltration membrane as well as a preparation method and application thereof. Belongs to the field of water treatment membrane preparation. The invention aims to solve the technical problems of non-uniform pore size distribution and surface hydrophobicity of the conventional nanofiltration membrane. The method comprises the following steps: adding tryptophan into a piperazine water-phase solution, and carrying out interfacial polymerization with oil-phase trimesoyl chloride to prepare the tryptophan modified nanofiltration membrane. According to the preparation method, the diffusion rate of the piperazine monomer can be adjusted in the interfacial polymerization process by utilizing a similar surfactant structure of tryptophan, meanwhile, the tryptophan has hydrophilicity and can improve the hydrophilicity of the surface of an active layer, and the prepared modified nanofiltration membrane is reduced in molecular weight cut-off, improved in surface hydrophilicity and good in water resistance. The retention rate of organic micro-pollutants is improved, and meanwhile, good anti-pollution performance is achieved.

The invention relates to the technical field of membrane separation, in particular to a high-flux high-salt rejection rate reverse osmosis membrane as well as a preparation method and application thereof. The preparation method comprises the following steps: sequentially contacting a porous base membrane with a water phase solution and an oil phase solution to generate an interfacial polymerization reaction to form a primary reverse osmosis membrane, and sequentially contacting the primary reverse osmosis membrane with a nitrous acid or salt solution thereof and a hydrosulfite solution to obtain the reverse osmosis membrane with high flux and high salt rejection rate, the water-phase solution contains a water-phase cosolvent, and the oil-phase solution contains an oil-phase cosolvent. According to the preparation method, cosolvents are creatively added into a water-phase solution and an oil-phase solution in an interfacial polymerization reaction process to regulate and control the microstructure of a polyamide layer, and a diazo reaction promotes further crosslinking of residual aniline groups, so that in-situ densification regulation and control of a polyamide network structure are realized; the trade-off effect of the water flux and the salt rejection rate of the traditional reverse osmosis membrane is successfully broken through.

The invention discloses a method for preparing a polyvinyl polyamide composite reverse osmosis membrane by coupling reversed-phase interfacial polymerization with lignosulfonate, which adopts a reversed-phase interfacial polymerization method and comprises the following steps: firstly adding an oil phase containing polyacyl chloride, and then adding a water phase containing amine monomers and lignosulfonate. Molecules of the lignosulfonate contain more sulfonate radicals, so that the lignosulfonate is endowed with hydrophilicity, meanwhile, a large number of active functional groups such as phenolic hydroxyl groups, alcoholic hydroxyl groups and carboxymethyl exist, and oxygen atoms, sulfur atoms and the like in the functional groups contain unbonded electron pairs and can participate in interfacial polymerization reaction to form a cross-linked structure; the trade-off effect of the flux and the rejection rate of the reverse osmosis membrane is broken, and the polyvinyl polyamide reverse osmosis membrane with high flux and high rejection rate is obtained. The raw material of the polyethylene base material is low in price, and the product can be applied to the fields of water treatment, seawater desalination, brackish water desalination and the like on a large scale.

This disclosure relates to the fabrication of high-performance thin film composite (TFC) reverse osmosis (RO) membranes comprising a thin polyamide rejection layer (thickness of 100-200 nanometer), a porous substrate including polysulfone (PSf) layer (thickness of 40-50 micron) cast on polyester nonwoven fabric (thickness of ˜100 micron). Hydrophilic and antibacterial TFC polyamide RO membranes were developed by incorporating green Lignin and nanostructured silver-based metal organic frameworks (MOFs) into the selective layer. The polyamide layer of TFC RO membranes was fabricated on the porous PSf substrate by interfacial polymerization between aqueous monomer solutions containing MPD, and adequate additives in water and organic monomer solutions containing TMC in the mixture of hexane and co-solvents. The optimized produced RO membranes were provided water flux of 95-100 LMH and sodium chloride (NaCl) salt rejection of 98.5-99.0% during filtration of 2000 ppm NaCl solution at 225 psi pressure, and water flux of 55-60 LMH and sodium chloride (NaCl) salt rejection of 98.6-98.9% during filtration of 35000 ppm NaCl solution at 800 psi pressure. This disclosure also relates to developing a roll-to-roll PSf membrane as a substrate for making TFC RO membranes for water desalination

The invention relates to the technical field of water treatment, in particular to a reverse osmosis membrane and a preparation method thereof. The preparation method of the reverse osmosis membrane comprises the following steps: soaking a base membrane in a water phase solution, taking out the base membrane, drying the surface of the base membrane, coating the base membrane with an oil phase solution, carrying out interfacial polymerization reaction, curing, coating with a modifier solution, and drying to obtain the reverse osmosis membrane, the modifying agent comprises 2, 4, 6-tri (4-aminophenyl)-1, 3, 5-triazine-1, 3, 5-tri (4-methyl phenyl) benzene. The successfully grafted COFs can improve the water permeability of the membrane to a certain extent, and also can improve the pollution resistance, acid resistance and oxidation resistance of the membrane, so that the service life of the membrane is prolonged. According to the invention, different effects of the same type of imino COFs introduced to the reverse osmosis membrane are further compared, so that the excellence of the selected imino COFs is highlighted.

The present invention relates to the field of water treatment technology, and more particularly to a kind of reverse osmosis membrane and preparation method thereof.The preparation method of the reverse osmosis membrane includes:Basement membrane is soaked in aqueous phase solution, after taking out surface drying, oil phase solution is coated on basement membrane and carries out interfacial polymerization reaction, after solidification, coating modifier solution, after drying, obtain reverse osmosis membrane;The modifier includes 2,4,6-tris (4-aminophenyl) ‑1,3,5-triazine ‑1,3,5-tris (4-methylphenyl) benzene.The COFs successfully grafted by the present invention can improve the water permeability of membrane to a certain extent, and can also improve the anti-pollution property, acid resistance and oxidation resistance of membrane, and then improve the service life of membrane.The present invention further compares the different effects that the same type of imino COFs are introduced into reverse osmosis membrane, so as to highlight the excellence of the imino COFs selected by the present invention.

The invention relates to the technical field of membrane separation, in particular to a preparation method of a pH-step-by-step thermocuring regulation sodium-magnesium separation nanofiltration membrane. The method comprises the following steps: (1) pre-treating a base membrane; (2) preparation and treatment of an aqueous phase solution: S1, preparing the aqueous phase solution according to mass fraction: sequentially adding 1.2%-1.6% of piperazine, 0.10%-0.14% of triaminopyrimidine and 0.14%-0.18% of polyethylene glycol into deionized water, and stirring until the piperazine, the triaminopyrimidine and the polyethylene glycol are completely dissolved to form the aqueous phase solution; s2, adjusting the pH value of the water-phase solution to 10-11 by using hydrochloric acid; s3, pouring the water-phase solution of which the pH is adjusted on the surface of the pretreated base membrane, standing, and blow-drying to form a uniform water-phase layer; (3) interfacial polymerization reaction: S1, preparing an oil phase solution: adding 0.10-0.14% of trimesoyl chloride into n-hexane, and performing ultrasonic treatment until the trimesoyl chloride is completely dissolved; s2, pouring the oil-phase solution on the surface of the base membrane subjected to water-phase treatment, and after reaction, pouring out redundant solution to form a polyamide separation layer, so as to obtain a membrane sheet; (4) performing a step-by-step thermocuring process; and (5) cleaning and storing.

The invention provides a preparation method of a high-flux stable-selection anti-fouling nanofiltration membrane, which comprises the following steps: carrying out amination modification on a nano material by an activation method to prepare a modified nano material; piperazine, an acid absorbent and the modified nano material are added into deionized water to be mixed, and a water phase solution is prepared; the preparation method comprises the following steps: mixing trimesoyl chloride and normal hexane to prepare an organic phase solution; immersing the polyethersulfone-based membrane into the water phase solution, draining, inversely immersing into the organic phase solution, and carrying out interfacial polymerization reaction to generate a polyamide layer to obtain a composite membrane; and then carrying out post-treatment on the composite membrane to obtain the composite membrane. The membrane has high permeability, high selectivity and strong anti-pollution performance.

The invention discloses a preparation method of a solvent-resistant nanofiltration membrane with a polydopamine / amino silicon dioxide middle layer, belongs to the technical field of membrane separation, and solves the technical problems of low flux and poor stability of the solvent-resistant nanofiltration membrane. The preparation method of the solvent-resistant nanofiltration membrane with the polydopamine / amino silicon dioxide middle layer comprises the following steps: preparing a polyetherimide-based membrane by a phase inversion method-crosslinking method; preparing amino silicon dioxide nanoparticles by adopting a sol-gel method; preparing a deposition solution containing dopamine, an oxidizing agent and amino silicon dioxide by using a Tris buffer solution; depositing the polydopamine / amino silicon dioxide intermediate layer on the upper surface of the polyetherimide base film; carrying out interfacial polymerization reaction of piperazine and trimesoyl chloride on the surface of the membrane deposited with the middle layer, and carrying out heat treatment to obtain a composite membrane; and immersing the composite membrane into an organic solvent for activation to obtain the solvent-resistant nanofiltration membrane with a polydopamine / amino silicon dioxide intermediate layer. The solvent-resistant nanofiltration membrane constructed by taking polyetherimide as a base membrane, polydopamine / amino silicon dioxide as a middle layer and polyamide as a separation layer has excellent flux and stability, and has a wide application prospect in the aspects of drug separation, organic solvent recovery and the like.

The invention discloses a heterojunction AgI / MIL-53 (Fe, Co) composite polyethersulfone membrane and a preparation method and application thereof. The heterojunction AgI / MIL-53 (Fe, Co) composite polyethersulfone membrane is composed of a polyethersulfone membrane, AgI modified MIL-53 (Fe, Co) nano particles loaded on the polyethersulfone membrane and a polyamide nano layer. Preparing by adopting a particle adding mode of vacuum filtration and interfacial polymerization modification; the mold material is good in permeability, high in mechanical strength and excellent in pollution resistance.

A method of preparing a polyamide membrane with multi-level pore structure mediated by protein fiber network includes the steps of: preparing protein fiber; quenching and carrying out dialysis; loading protein fiber network on ultrafiltration membrane; preparing aqueous and organic phase solutions; and carrying out interfacial polymerization, which can solve the problems of the integrity and separation performance of the polyamide layer being affected by low porosity of the base membrane and uneven distribution of amine monomers. The polyamide membrane prepared by the method of the present invention greatly improves the water flux while ensuring a high salt rejection rate. At the same time, the introduction of the protein fiber network also enhances the mechanical strength and anti-pollution ability of the membrane.

Membranes and related systems and methods for separation of components in liquids are generally described. The membrane may include particles in a polymer matrix (e.g., a polyamide layer). The particles may include metal-organic framework particles comprising functional groups (e.g., from post-synthetic modification) that can, in some instances, improve the rejection and / or selectivity of the membrane. For example, the metal-organic framework may comprise functional groups bound to hydrophobic groups (e.g., alkyl chains) that assist with suspension stability in nonpolar solvents during membrane fabrication. As another example, the metal-organic framework may comprise functional groups bound to crosslinking agents that facilitate in situ crosslinking of the particles with the polymer matrix, thereby reducing voids in the membrane and / or leaching. In some instances, the membrane is a thin-film nanocomposite membrane (e.g., for separating components like charged species and / or neutral species) formed via, for example, interfacial polymerization in the presence of the particles.

The invention relates to a super-flexible supercapacitor with a multi-layer seamless interlocking interface and a preparation method of the super-flexible supercapacitor. The super-flexible supercapacitor takes a carbon nanotube or a composite film thereof as an electrode; and polyanion gel (polyacrylamide / polyacrylic acid / poly (3-sulfonic acid propyl methyl acrylic acid potassium salt) and polycation gel (polyacrylamide / polyacrylic acid / poly (methacryloyloxyethyl trimethyl ammonium chloride) are used as the double-layer heterogeneous electrolyte. A covalent connection electrode / electrolyte interface is constructed through anchoring interface polymerization, and double-layer gel electrolyte with electrostatic attraction and mutual entanglement is constructed through in-situ polymerization, so that the super-flexible supercapacitor with a multi-layer seamless interlocking interface is realized. Compared with the prior art, the super capacitor has super-strong interface toughness and interface adhesion, can resist mechanical deformation including bending, folding, twisting, winding, extruding, knotting and the like, the capacity retention ratio is greater than 95% after the super capacitor is folded for hundreds of thousands of times, and the capacity retention ratio is greater than 89% after the super capacitor is circularly charged and discharged for hundreds of thousands of times.

The invention relates to a bionic strong acid-resistant nanofiltration membrane and a preparation method thereof, and the bionic strong acid-resistant nanofiltration membrane comprises a porous support layer and an active separation layer formed on the surface of the porous support layer, the active separation layer is a polymer network layer formed by carrying out interfacial polymerization reaction on a water-phase solution containing polyamine and an oil-phase solution containing polyacyl chloride on the surface of the porous support layer. The water-phase solution and / or the oil-phase solution also contains a bionic amphiphilic phosphate compound, the bionic amphiphilic phosphate compound participates in interfacial polymerization reaction through an active functional group in a molecular structure of the bionic amphiphilic phosphate compound, and the phosphate structure of the bionic amphiphilic phosphate compound is covalently connected into a skeleton of the polymer network layer. The preparation method has the beneficial effects that the bionic amphiphilic phosphate compound with a hydrophilic phosphate head, a hydrophobic alkyl tail and a reaction site is synthesized, so that the bionic amphiphilic phosphate compound is spontaneously and orderly arranged on a water / oil interface and participates in interfacial polymerization, the film forming uniformity is improved, the pore size distribution is narrowed, and the intelligent response characteristic is given to the film.

The invention discloses a method for improving water flux and anti-pollution capacity of a polyamide reverse osmosis membrane and application of the method, and belongs to the technical field of water treatment membranes.The method comprises the steps that a water-phase solution containing polyamine monomers and an oil-phase solution containing polyacyl chloride monomers are respectively subjected to droplet formation into a water-phase solution containing polyamine monomers and an oil-phase solution containing polyacyl chloride monomers through a droplet generator, and the water-phase solution containing polyamine monomers and the oil-phase solution containing polyacyl chloride monomers have the particle size of 10-200 microns; water phase solution droplets and oil phase solution droplets with the specific surface area of 3 * 10 < 4 >-6 * 10 < 5 > m < 2 > / m < 3 > are sequentially sprayed on the ultrafiltration substrate membrane through a moving spray head system, so that the water phase solution droplets and the oil phase solution droplets are fully contacted to generate an interfacial polymerization reaction, and after the spraying process is finished, heat treatment is performed to obtain the polyamide reverse osmosis membrane. According to the method disclosed by the invention, the traditional interfacial polymerization method is improved, a new additive is not introduced, and the water flux and the anti-pollution capacity of the polyamide reverse osmosis membrane are further improved on the basis of reducing the solvent dosage.

The invention provides a chlorine-resistant high-flux salt lake lithium extraction separation membrane and a preparation method, and belongs to the technical field of salt lake lithium extraction membrane separation.The preparation method specifically comprises the following steps that 1, a hollow fiber base membrane is prepared, specifically, a polymer, a solvent and an additive are mixed to form a membrane casting solution, and the hollow fiber base membrane is prepared through a spinning technology; step 2, modifying a piperazine monomer, and reacting the piperazine monomer with bis (2-chloroethyl) amine to generate a piperazine monomer with a spiral structure; 3, interfacial polymerization: the base membrane is sequentially immersed in a modified piperazine monomer solution and a trimesoyl chloride (TMC) solution for interfacial polymerization reaction, a thin spiral net structure functional separation layer is formed, and the formed nanofiltration membrane has the performance of chlorine resistance, high flux, high selective separation and the like. The key problems of low Mg < 2 + > / Li < + > separation efficiency, poor chlorine resistance of the membrane, insufficient flux and the like in lithium extraction from the salt lake are solved, the lithium recovery rate is remarkably increased, and the service life of the membrane is remarkably prolonged.

The invention belongs to the technical field of membrane separation, and particularly relates to a method for preparing a high-flux hollow fiber nanofiltration membrane based on interfacial polymerization, the obtained membrane and application. The method comprises the following steps: firstly, carrying out pre-adsorption treatment on a polyethersulfone hollow fiber ultrafiltration base membrane through a polyethyleneimine aqueous solution to form a reactive anchoring layer; then sequentially dipping in an aqueous phase solution containing piperazine, sodium phytate and nanoscale cellulose whiskers and an organic phase solution containing trimesoyl chloride and 5-isocyanate isopeptide acyl chloride for interfacial polymerization; and finally, carrying out heat treatment on the obtained primary composite membrane, and completing a gas-phase cross-linking reaction in a glutaraldehyde steam atmosphere. According to the method, the hollow fiber nanofiltration membrane with high flux, high selectivity, excellent chlorine resistance and pollution resistance is successfully prepared through a multi-stage strengthening process, and the hollow fiber nanofiltration membrane is suitable for the fields of drinking water purification, industrial wastewater reuse, material separation and the like.

The invention discloses a crown ether modified nanofiltration membrane for selective separation of lithium and magnesium and a preparation method of the crown ether modified nanofiltration membrane, and belongs to the technical field of membrane separation. The preparation method comprises the following steps: by taking a porous ultrafiltration membrane as a substrate and 2-aminomethyl-18-crown-6 ether and polyamine as water-phase monomers, carrying out interfacial polymerization reaction on the water-phase monomers and trimesoyl chloride on the surface of the porous ultrafiltration membrane to form a polyamide layer; wherein 2-aminomethyl-18-crown-6 ether is introduced into the polyamide separation layer in the form of a covalent bond through a reaction with trimesoyl chloride. The prepared nanofiltration membrane can effectively intercept Mg < 2 + > and provide an exclusive transport channel for Li < + >, so that the Li < + > smoothly crosses the membrane, and the lithium-magnesium separation effect is achieved. The method is simple in preparation process operation, low in energy consumption and easy to amplify, can be used for salt lake lithium extraction, and has a wide industrial application prospect.

The invention discloses a preparation method of a solvent-resistant nanofiltration membrane and the solvent-resistant nanofiltration membrane. The preparation method comprises the following steps: infiltrating a polyethylene-based membrane; performing hydrophilic modification treatment on the infiltrated polyethylene base membrane by using a hydrophilic modification solution to obtain a precursor base membrane; preparing a water phase solution containing UiO-66, and preparing an oil phase solution containing polyfunctional aromatic acyl chloride; performing interfacial polymerization reaction on the surface of the precursor base membrane by using the water-phase solution and the oil-phase solution to obtain a polyethylene nanofiltration membrane; performing cross-linking treatment on the polyethylene nanofiltration membrane by using a cross-linking solution to obtain the solvent-resistant nanofiltration membrane, wherein the solute of the hydrophilic modification solution comprises dopamine and polyethyleneimine. Hydrophilic modification treatment of dopamine and polyethyleneimine is carried out on the polyethylene film, and UiO-66 nanoparticles are added into a water-phase solution, so that the flux and the interception performance of the film are remarkably improved.

The invention belongs to the technical field of membrane separation, and particularly relates to a low-pressure high-flux polyamide / polysulfone hollow fiber composite nanofiltration membrane and a preparation method thereof. The preparation method of the composite nanofiltration membrane comprises the following steps: dissolving sulfonated polysulfone, poly (1-vinyl-3-butylimidazole) bromide and polyvinylpyrrolidone to prepare a spinning solution, and spinning to obtain a base membrane; carrying out hydrophilic modification on the base membrane by using 1, 3-propane sultone; then, an aqueous phase solution containing poly (gamma-glutamic acid) and triethylene tetramine and an organic phase solution containing trimesoyl chloride and 3, 5-diaminobenzoic acid are subjected to interfacial polymerization in the inner cavity of the modified base membrane to form a polyamide separation layer; and finally, carrying out heat treatment to obtain the composite nanofiltration membrane. Through the synergistic effect of zwitterionic ionization of the base membrane and biomacromolecule construction of the separation layer, the mass transfer resistance of water is remarkably reduced, unification of high flux and high selectivity is achieved, and good structural stability is achieved.

The invention belongs to the field of membrane separation, and provides a conductive nanofiltration membrane, a roll type conductive membrane filter element and a nanofiltration separation method.The conductive nanofiltration membrane comprises a substrate layer, a conductive layer and a separation layer and is prepared through a two-step vacuum filtration process and a vacuum filtration assisted in-situ interfacial polymerization method; meanwhile, good conductivity and selective separation capability are realized. In addition, the invention also provides a roll-type conductive membrane filter element based on the conductive nanofiltration membrane, and the roll-type conductive membrane filter element comprises the conductive nanofiltration membrane, a central conduit with a plurality of side holes, a water production diversion separation net, a water inlet diversion separation net, a counter electrode conductive layer, a conductive connector lug and a metal sheet (used for power connection), the roll type conductive membrane filter element can dynamically regulate and enhance the separation performance of charged molecules, ions and the like under the action of an electric field, and has the characteristics of simple structure, easiness in operation and amplification and adjustable and controllable membrane performance.

The invention discloses a preparation method and application of a cross-basement membrane back-diffusion in-situ growth ZIF modified polyvinyl polyamide positively charged nanofiltration membrane. The preparation method comprises the following steps: firstly, coating a support membrane by using an organic phase solution containing a trimesoyl chloride monomer; the preparation method comprises the following steps: preparing a supporting basement membrane, pouring a mixed aqueous solution of polyethyleneimine and zinc nitrate hexahydrate on the supporting basement membrane to carry out interfacial polymerization, overturning the supporting basement membrane after polymerization, pouring a 2-methylimidazole aqueous solution on the surface, carrying out cross-basement membrane in-situ growth of ZIF, and carrying out heat treatment and alcohol activation on the membrane after growth. According to the method disclosed by the invention, ZIF particles can be more uniformly generated in the membrane, interface gaps caused by MOF agglomeration are avoided, a high-positive-electricity layer can be prepared by combining a reverse-phase interface polymerization method in which polyethyleneimine is used as a water-phase monomer, and the water permeation flux is greatly improved while high interception of magnesium ions is maintained; the problem of mutual restriction of permeability and selectivity is solved, the process is simple, and preparation conditions are mild.

The invention relates to the technical field of compound microbial fertilizers, in particular to a biochar-based compound microbial fertilizer for improving saline-alkali soil. The organic fertilizer comprises the following components in parts by weight: 30-50 parts of straws, 10-15 parts of compound microbial capsules, 20-40 parts of compost and 5-10 parts of humic acid. A multi-strain mixture composed of azotobacter chroococcum, pseudomonas and bacillus mucilaginosus is added, and comprehensive improvement of the saline-alkali soil is achieved; the azotobacter chroococcum can convert nitrogen in the air into nitrogen which can be utilized by plants, so that the dependence on chemical fertilizers is reduced; pseudomonas has efficient phosphate solubilizing capacity, and bacillus mucilaginosus can strongly solubilize potassium, so that the soil fertility is comprehensively improved. Composite microorganisms and polylactic acid are subjected to an interfacial polymerization reaction to prepare microcapsules, dopamine hydrochloride is utilized to form a coating on the surfaces of the microcapsules in a self-assembly mode, physical protection can be provided for the microorganisms, the survival rate of the microorganisms in a severe environment is increased, and the acting time of the microorganisms in soil is prolonged.