751 results about "Polysulfone" patented technology

The invention relates to the technical field of hydrogen production by alkaline electrolyzed water, in particular to an anti-stripping alkaline electrolyzed water diaphragm casting solution, a diaphragm, a preparation method and application. The anti-stripping alkaline electrolyzed water diaphragm casting solution is prepared from the necessary solvent, the polydimethylsiloxane material, the polysulfone material, the inorganic nano-particles, the pore-forming agent, the cross-linking agent and the catalyst, and the polydimethylsiloxane material, the cross-linking agent and the catalyst act together, so that the enveloping of the inorganic nano-particles can be improved; the mechanical property of the membrane casting liquid on the membrane supporting layer is improved, and the anti-stripping effect is achieved. The diaphragm prepared by adopting the alkaline electrolyzed water diaphragm casting solution shows relatively low sheet resistance and stripping resistance, is good in air tightness, and is suitable for preparing the diaphragm of alkaline electrolyzed water hydrogen production equipment, so that the effects of maintaining free movement of ions in an electrolytic bath and blocking mixing of hydrogen and oxygen are achieved.

The invention discloses a preparation method and application of a ternary multifunctional three-dimensional framework mediated high ammonia nitrogen selectivity polyamide reverse osmosis membrane, and belongs to the technical field of membrane separation. The method comprises the following steps: 1, preparing a high-molecular copolymer; 2, preparing a polysulfone support layer by adopting a non-solvent induced phase inversion method; 3, preparing a polyamide reverse osmosis membrane by adopting an interfacial polymerization method; and 4, preparing the polyamide reverse osmosis membrane with high ammonia nitrogen selectivity. Through reasonable design of the structure and distribution of the group of the ternary multifunctional three-dimensional structure high-molecular copolymer, the copolymer can react with the acyl chloride group on the surface of the polyamide active layer to form a covalent amido bond, and the covalent amido bond is anchored on the surface of the polyamide layer in situ to construct the functional layer. The functional layer not only can significantly improve the surface potential of the membrane, but also can increase the inherent concentration of ammonia nitrogen on the surface of the membrane, thereby increasing the diffusion resistance, finally realizing the repulsive force to the ammonia nitrogen, and improving the interception capability of the grafted membrane to the ammonia nitrogen. The operation process is simple and mild, the whole membrane preparation process is not changed, and industrialization is easy.

The invention provides a photovoltaic wastewater resource utilization method and system, and the method comprises the following steps: sequentially carrying out peroxide removal treatment and filtration treatment on photovoltaic wastewater to obtain filtered effluent; carrying out silicon element separation treatment on the filtered effluent to obtain sodium-rich wastewater and silicon-rich wastewater; carrying out heavy metal removal treatment and anion removal treatment on the sodium-rich wastewater to obtain a product alkali liquor; the peroxide removal treatment comprises the step of enabling the photovoltaic wastewater to be in contact with a catalytic filler, wherein the catalytic filler comprises at least one of manganese sand, ferric oxide and aluminum oxide; the silicon element separation treatment comprises the step of treating the filtered effluent by using a silicon element separation membrane element; the silicon element separation membrane element is selected from at least one of polysulfone, polyamide, sulfonated polyethersulfone or sulfonated polysulfone. The photovoltaic wastewater resource utilization method provided by the invention has the technical effects of cyclic utilization of the photovoltaic wastewater and relatively low cost.

The invention discloses a modified hollow fiber membrane which is composed of a separation layer, a supporting layer and a macroporous layer, the pore diameters of the separation layer, the supporting layer and the macroporous layer are sequentially increased, and a preparation method of the modified hollow fiber membrane comprises the following steps: weighing polyether sulfone / polysulfone, a pore-foaming agent, a solvent, an organic macromolecular additive and an inorganic salt additive according to the proportion to prepare a spinning solution; stirring and dissolving at 80-180 DEG C, centrifugally filtering, defoaming at 40-80 DEG C to obtain a spinning solution, carrying out coagulating bath on the spinning solution, molding, cleaning, stretching and drying to obtain the modified hollow fiber membrane. According to the preparation method, micromolecular inorganic salt pore-forming agents with different concentrations are added into a spinning solution and a coagulating bath, and interaction among inorganic salt, a polymer and a solvent is utilized, so that an inner skin layer structure and an outer skin layer structure of the hollow fiber membrane are adjusted, and a unique three-layer structure of a separation layer, a supporting layer and a macroporous layer is formed; the hydrophilic performance is stable, and the clearance on middle molecules is improved.

The invention relates to the technical field of reverse osmosis membranes, in particular to a polyamide reverse osmosis membrane for high-salinity wastewater treatment and a preparation method of the polyamide reverse osmosis membrane. The invention solves the problem that the polyamide reverse osmosis membrane cannot give consideration to both desalination rate and water flux. The polyamide reverse osmosis membrane comprises a polyester non-woven fabric layer, a polysulfone porous layer, a transition layer and a polyamide layer. The polysulfone porous layer is prepared, and the modified pore-forming agent is added to improve the water flux of the reverse osmosis membrane; the hydrophilicity of the reverse osmosis membrane is improved by preparing the transition layer and adding a hydrophilic auxiliary agent when the polyamide layer is prepared; the flux attenuation rate of the polyamide reverse osmosis membrane is reduced by preparing the polyamide layer; the desalination rate of the reverse osmosis membrane is improved by introducing a composite ion complexing agent and graphene quantum dots into the polyamide layer.

The invention discloses an anti-pollution modified hollow fiber membrane and a preparation method and application thereof.The anti-pollution modified hollow fiber membrane can be tightly combined with a zwitterionic polymer material modified nano-antibacterial material, and is prepared from, by weight, 8-30% of polyvinylidene fluoride (PVDF) / polysulfone / polyethersulfone, 0.1-15% of a modified material, 0.1-10% of an antioxidant and the balance water. According to the present invention, the prepared hollow fiber membrane has characteristics of excellent pollution resistance, no filament breaking, and application in wastewater treatment, pollution control, water resource comprehensive utilization, food processing, medicine purification, and other aspects, and the prepared hollow fiber membrane has characteristics of excellent pollution resistance, no filament breaking, and can be used in the fields of wastewater treatment, pollution control, water resource comprehensive utilization, food processing, medicine purification, and the like.

The invention relates to the technical field of reverse osmosis membrane supports, in particular to a polyester non-woven fabric and a preparation method and application thereof.The preparation method comprises the steps that S1, polyester main body fibers and polyester adhesive fibers are used as raw materials to prepare high-quantitation original cloth M0 and low-quantitation original cloth H0; carrying out hot pressing pretreatment on the H0 to obtain a product H0 '; s2, overlapping and hot-pressing M0 and H0 'to obtain a composite non-woven fabric M1H1; s3, the M1H1 is impregnated with a functional solution, and the functional solution contains para-aramid nanofibers and nano calcium carbonate modified by hexadecyl trimethyl ammonium bromide; and then carrying out cold pressing on the composite non-woven fabric impregnated with the functional solution to obtain the nano-material modified composite non-woven fabric. And S4, carrying out secondary hot pressing treatment to obtain the polyester non-woven fabric. The polyester non-woven fabric can effectively avoid the problems of excessive curling, excessive permeation of a polysulfone solution and the like during curing after being coated with polysulfone, and is more beneficial to application in a reverse osmosis membrane.

According to the method for preparing the polyamide / sulfonated COFs reverse osmosis membrane through in-situ copolymerization, a polysulfone ultrafiltration membrane is used as a supporting layer, a water-phase monomer solution and an organic-phase monomer solution are subjected to a one-step in-situ copolymerization reaction on a water-phase / organic interface on the supporting layer, and the polyamide / sulfonated COFs reverse osmosis membrane is prepared. The preparation method is simple in technological process and low in cost, the sulfonated COFs material is introduced into a polyamide layer through one-step interface in-situ copolymerization, the dispersity and compatibility of the sulfonated COFs can be well enhanced, the interface polymerization process is regulated and controlled by fully utilizing a porous structure, hydrophilicity and indirect control of monomer diffusion, and the like, and the preparation method is suitable for large-scale industrial production. The trade-off effect of a traditional polyamide reverse osmosis membrane is broken through, the salt rejection rate is increased while high water flux is guaranteed, and the polyamide reverse osmosis membrane has very high practical application value.

The present invention discloses a high-performance reverse osmosis membrane and a method for preparing the same. The reverse osmosis membrane comprises a polyester non-woven fabric layer, a polysulfone-based membrane, and a polyamide skin layer stacked in sequence. The polysulfone-based membrane has a micron-scale prism structure on the side away from the polyester non-woven fabric layer. The preparation method comprises coating the surface of the polyester non-woven fabric layer with the polysulfone-based membrane, and forming the micron-scale prism structure on the surface of the polysulfone-based membrane by cold pressing with a roller mold during the process of converting the polysulfone-based membrane from a liquid state to a solid state. The present invention improves the flux without affecting the desalination rate of the reverse osmosis membrane or sacrificing the thickness of the skin layer, thereby resolving the trade-off between flux and desalination in the current technology. At the same time, the micron-scale prism structure can be designed into different shapes according to performance requirements, thereby achieving precise control of the flux performance of the reverse osmosis membrane.

The present invention relates to the technical field of seawater desalination membranes, and discloses a durable seawater desalination membrane and a preparation method thereof. The present invention uses pentaerythritol as an initiator, uses propylene oxide and ethylene oxide as raw materials to synthesize a hyperbranched polyether, and then undergoes an ester exchange reaction with 2-aminoethyl acetate to synthesize a modified hyperbranched polyether. The ZIF-8 material is then synthesized by a hydrothermal method, and MoS2 nanosheets are coated on its surface to obtain a MoS2 / ZIF-8 composite material, which is then surface-modified by a silane coupling agent to obtain a modified MoS2 / ZIF-8 composite material. Finally, a casting solution is formed using polysulfone and a modified MoS2 / ZIF-8 composite material to obtain a base membrane, and the base membrane is then sequentially immersed in an aqueous phase solution and an oil phase solution to form a polyamide film layer, thereby obtaining a durable seawater desalination membrane. The seawater desalination membrane prepared by the present invention has excellent water flux, desalination rate and durability.

The invention belongs to the technical field of modified special plastics, and provides a polysulfone composite material for an extremely-high-temperature-resistant safety helmet and a preparation method and application thereof.The polysulfone composite material is prepared from, by mass, 24-40% of bisphenol A type polysulfone resin, and the melt index gt of the bisphenol A type polysulfone resin is measured at the temperature of 343 DEG C and 2.16 kg; the oxygen index gt is 5 g / 10 min; 30); the glass transition temperature of the nylon resin is greater than or equal to 130 DEG C, and the relative viscosity of the nylon resin is 1.8-2.2; 3-6% of a compatilizer; 5 to 10% of a maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer; 25-35% of glass fiber; 0.3%-0.7% of an antioxidant; and 0.3-0.7% of a lubricant. The composite material is prepared from the raw materials, and the prepared safety helmet has excellent comprehensive mechanical properties, such as combustion resistance, 150 DEG C bending strength, impact absorbing force and maximum lateral rigidity deformation at 150 DEG C.

The invention provides a preparation method of a quick-dissolution reverse osmosis basement membrane, the reverse osmosis basement membrane prepared by the preparation method and application, and relates to the technical field of reverse osmosis basement membrane preparation. The preparation method comprises the following steps: mixing a pre-casting membrane solution containing polysulfone and a solution containing an amphiphilic block copolymer to obtain a casting membrane solution; coating the surface of a base material with the casting film solution to obtain the base material with a wet film layer; immersing the base material with the wet film layer into a coagulating bath, and obtaining a base film with a modified polysulfone layer through a non-solvent induced phase transformation method; sequentially contacting the base membrane with the modified polysulfone layer with a water-phase monomer solution containing m-phenylenediamine and an oil-phase monomer solution containing trimesoyl chloride, and curing to form a polyamide layer, so as to obtain the reverse osmosis base membrane capable of being quickly dissolved out. The TOC dissolution amount of the reverse osmosis membrane material can be effectively reduced, the TOC dissolution process is accelerated, it is ensured that the membrane can rapidly reach the preset water quality standard in the initial use stage, and the performance stability of the membrane is improved.

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 discloses a solution concentration device for a water purifying agent, which comprises a top concentration tank and a bottom concentration tank, and the top concentration tank is erected above the bottom concentration tank. The device has the beneficial effects that the top concentration tank is adopted, when the top concentration tank is used for concentrating a water purifying agent solution, a worker can pump the water purifying agent solution into a first flow dividing disc in a pressurizing manner through a pressurizing conveying pump, and the water purifying agent solution enters an inner pipe after being divided by the first flow dividing disc; a pressure maintaining valve mounted on the surface of the inner pipe keeps the internal pressure of the inner pipe, pure water in a water purifying agent solution enters the bottom of the top concentration tank after penetrating through a polyamide film layer, a polysulfone supporting layer and a polyester substrate layer and is discharged along a water discharging pipe, and after a part of pure water is filtered out by pressurizing a water purifying agent solvent in the inner pipe, primary concentration is completed; the energy consumption is far lower than that of traditional high-temperature concentration and low-temperature concentration when the pressurizing delivery pump works, and the pressurizing delivery pump is more energy-saving and environment-friendly, higher in speed and higher in working efficiency and working continuity.

The invention relates to the technical field of polysulfone resin production, and discloses polysulfone resin and a production process thereof. The polysulfone resin production process comprises the following steps: preparing a polysulfone resin solution, and carrying out solid-liquid separation on the polysulfone resin solution to prepare a filtered polysulfone resin solution; steam is sprayed into the precipitation drying kettle at the pressure not lower than 0.5 MPa, so that a flowing high-pressure steam environment is formed in the kettle; spraying the filtered polysulfone resin solution into flowing high-pressure steam in a mist form, so that a solvent in the polysulfone resin solution is gasified to form solvent gas and discharged along with the steam, and polysulfone resin is solidified and separated out in a particle form; and drying the separated polysulfone resin particles to obtain the polysulfone resin. According to the technical scheme provided by the invention, the production efficiency of the polysulfone resin can be improved, and the purity of the prepared polysulfone resin can be improved.

The present disclosure relates to a membrane prepared from a blend comprising i) a polysulfone, polyether sulf one or polyarylethersulfone and ii) polyvinylpyrrolidone, characterized in that the membrane is coated with polydopamine and chon-droitin. Optionally the coating further comprises heparin. The disclosure further relates to a process for producing the coated membrane, a method of increasing the selectivity of a membrane, and to a filtration / diffusion device comprising the membrane which can be used, for example, in hemodialysis applications.

The invention discloses a chlorine-resistant polyamide composite nanofiltration membrane and a preparation method thereof. The composite nanofiltration membrane is composed of a polysulfone-based membrane, and a catechol intermediate layer and a polyamide desalination layer which are sequentially arranged on the polysulfone-based membrane, wherein the catechol middle layer comprises a plurality of catechol self-polymerization layers, and catechol is subjected to oxidation self-polymerization and then is constructed on the polysulfone base membrane layer by layer to obtain the catechol self-polymerization layers; and the polyamide desalination layer is constructed on the catechol intermediate layer through an interfacial polymerization reaction. The chlorine-resistant polyamide composite nanofiltration membrane comprises a polysulfone base membrane, a catechol middle layer and a polyamide desalination layer, the catechol self-polymerization middle layer is formed through a layer-by-layer construction technology, certain chlorine resistance is provided, meanwhile, the possibility that the middle layer falls off is reduced, and the stability of the composite nanofiltration membrane is enhanced; the tannic acid is added into a water-phase solution, so that the performance of the polyamide composite nanofiltration membrane is adjusted, and the polyamide composite nanofiltration membrane is endowed with relatively high chlorine resistance.

A membrane includes a polysulfone-based support, a polydopamine (PDA) layer disposed on a surface of the polysulfone-based support, and a silver / polydopamine (Ag / PDA) composite layer disposed on a surface of the polydopamine layer. The polysulfone-based support has a pore size of up to 600 nanometers (nm). The Ag / PDA composite layer contains core-shell structure particles and spherical particles. The core-shell structure particles have a silver nanoparticle core and a polydopamine shell. The spherical particles are silver-decorated polydopamine particles. The membrane can at least partially separate an Erichrome Black T (EBT) dye from an EBT dye / salt containing mixture by rejecting the EBT dye and allowing the EBT dye / salt containing mixture to pass through the membrane.

The invention provides a composite solid electrolyte membrane, a preparation method thereof and a solid lithium metal battery. The preparation method comprises the following steps that an organic-inorganic composite membrane is provided, the organic-inorganic composite membrane comprises organic components and inorganic components, and the organic components comprise polysulfone organic matter; and soaking the organic-inorganic composite membrane in a salt solution, and drying to obtain the composite solid electrolyte membrane. According to the invention, the polysulfone organic matter with high dielectric strength is introduced into the organic-inorganic composite membrane, so that the electrochemical window of the composite solid electrolyte membrane is remarkably improved, and the normal work of the battery in a relatively high voltage range is ensured.

The invention discloses hydrophilic modified polysulfone resin with side carboxyl groups and a preparation method of the hydrophilic modified polysulfone resin, and relates to the technical field of polysulfone. According to the invention, desalted water is used as a salt-forming solvent to carry out a salt-forming reaction of the bisphenol monomer, after the salt-forming reaction is finished, the salt-forming agent of the system is reacted and alkalinity is weakened, and then an NMP solvent is added to carry out water sampling, so that interference of NMP decomposition on carboxyl in a salt-forming stage is reduced, and the proportion of diphenolic acid connected with a molecular chain is consistent with a feeding ratio; the formed hydrophilic modified polysulfone resin is more stable in component; meanwhile, before end capping, side chain carboxyl forms a stable coordination complex, so that the end capping can be performed on the diphenolic acid type hydrophilic polysulfone, the content of phenol end groups with poor thermal stability is greatly reduced, and the natural color can be kept during extrusion granulation.

The invention relates to a polyester composition as well as a preparation method and application thereof, and the polyester composition comprises the following components in parts by weight: 40-60 parts of polyester resin, 5-20 parts of a brominated flame retardant, 0.5-5 parts of a synergistic flame retardant, 0.1-15 parts of polysulfone, 0.05-5 parts of talcum powder and 15-40 parts of a reinforcing material, the polyester composition does not contain PFAS substances. On the basis of retaining a brominated flame-retardant system, polysulfone and talcum powder are combined with the brominated flame-retardant system, so that the flame-retardant property of the material under a thin wall is obviously improved under the condition of not using PFAS substances, and the application prospect of the polyester material is expanded.

The invention provides a metal organic framework composite adsorbent, a preparation method thereof and a hemoperfusion device, and belongs to the technical field of blood purification adsorption materials. The metal organic framework composite adsorbent provided by the invention is a metal organic framework material-polysulfone material composite sphere, the metal organic framework material has excellent adsorbability to various toxins, and the polysulfone material has good biocompatibility, mechanical strength, processing adaptability and sterilization capability; therefore, the metal organic framework composite adsorbent has good blood compatibility and toxin adsorbability, is less in adsorbent particle falling, and is suitable for the field of whole blood perfusion. The result of the embodiment shows that the metal organic framework composite adsorbent provided by the invention has excellent adsorption performance on p-cresol sulfate, indoleacetic acid, bilirubin, bile acid and endotoxin, and shows excellent blood compatibility.

A composite membrane for desalination includes a polyethylene terephthalate (PET) nonwoven layer having a fibrous structure, and has an average thickness of about 30 to 200 micrometers (μm). A polysulfone (PS) layer having an average thickness of about 30 to 100 μm is disposed on a surface of the PET nonwoven layer. Further, a polyamide layer is disposed on a surface of the PS layer including reacted units of an acyl compound, a phenylenediamine monomer, and a poly-(DADMAC-co-DADA). The polyamide layer has a rough surface including a plurality of irregular-sized ridge-and-valley structures of polyamide. The poly-(DADMAC-co-DADA) has a formula (I), and n is a positive integer.

The invention discloses a phase-change heat-storage fluffy fiber and a preparation method thereof. According to the method, polyethylene glycol, microcapsules, fatty acid, paraffin or alkane and the like are used as phase change heat storage materials, elastic polymers such as polystyrene, polyurethane, polyamide and the like are used as elastic spinning materials, and hydrophobic polymers such as polyacrylonitrile, polysulfone, polytetrafluoroethylene, polyvinylidene fluoride and the like are used as hydrophobic spinning materials; the phase-change heat-storage fluffy fiber is prepared in a high-humidity environment through an electrostatic spinning method. The phase-change heat-storage fluffy fiber synthesized by the method is in a flexible fluffy form and has the advantages of good phase-change stability, low heat conductivity coefficient and the like, and the environmental temperature is kept stable through an accompanying heat absorption or heat release effect when phase change occurs at the phase-change temperature; the material can be used as a thermal insulation filling material and has wide application prospects in human body and environment thermal management and other aspects.

The invention relates to the technical field of antistatic agents, and particularly discloses an oil product antistatic agent and a preparation method thereof. The modified polysulfone is obtained by mixing and treating the following raw materials in parts by mass: 35-40 parts of xylene, 20-25 parts of composite polyamine, 15-20 parts of polysulfone, 5-8 parts of oligomeric dopamine and 1-2 parts of an activating agent, the preparation method comprises the following steps: taking composite polyamine, mixing with oligomeric dopamine, dispersing with xylene, then adding an activator, stirring, then adding polysulfone, and continuously treating, thereby obtaining the product. The preparation method of the composite polyamine comprises the following steps: taking epichlorohydrin, dispersing, adding a mixed amine source, heating, adding sodium carbonate, continuously stirring, cooling, adding a deprotection agent, filtering after treatment, taking a liquid part, drying by distillation, washing, drying again, and grinding to obtain the composite polyamine. The oil product antistatic agent prepared by the invention has relatively strong antistatic capability and relatively long duration time, and can form a firmer double-electric-layer structure.

The invention discloses a ZIF-7-OH surface modified polysulfone composite oil-water separation membrane as well as a preparation method and application thereof. Through simple blending and non-solvent induced phase inversion, the method comprises the following specific steps: firstly, synthesizing a hydrophobic polymer through free radical polymerization, and then blending the hydrophobic polymer with a polysulfone matrix to form a membrane casting solution; secondly, hydroxylated ZIF-7 (ZIF-7-OH) particles are fixed to the surface of the membrane through a non-solvent induced phase inversion method; wherein due to the introduction of hydroxyl, particles and hydrophobic polymers with siloxane groups can be coupled and fixed on the membrane, so that the stability of the particles on the surface of the membrane is improved, and finally, the super-hydrophobic polysulfone composite membrane for efficient oil-water emulsion separation is obtained. The ZIF-7 particles are creatively hydroxylated and fixed to the surface of the membrane through a coupling effect, and the micro-nano rough structure and the low-surface-energy substance have a synergistic effect, so that the membrane is endowed with super-hydrophobicity and excellent self-cleaning performance, and the composite membrane has efficient oil-water emulsion separation capacity.

The invention belongs to the technical field of new materials, and relates to a layered double hydroxide film using polysulfone resin as a binder, and the layered double hydroxide film is obtained by connecting layered double hydroxide particles or layered double hydroxide nanosheets into a continuous film by using the polysulfone resin as the binder. The invention further relates to a preparation method and application of the layered double hydroxide film with the polysulfone resin as the binder. The layered double hydroxide membrane provided by the invention adopts the LDH with anionic conductivity as a main body, and the surface resistance of the layered double hydroxide membrane in an alkaline solution is obviously lower than that of a commodity Zirfon membrane, so that the membrane provided by the invention can show higher electrolysis efficiency when being used for water electrolysis. The membrane forming method is based on the common phase inversion principle in separation membrane preparation in the field of chemical separation, so that large-scale preparation can be conveniently achieved through technological parameter change on the basis of mature industrial equipment for separation membrane phase inversion preparation, and batch preparation is easy to achieve.

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 discloses a preparation method of polysulfone with stable color and reduced yellowness, which comprises the following steps: by using N-methyl pyrrolidone as a reaction solvent, reacting bisphenol A with 4, 4 '-dichlorodiphenyl sulfone in the presence of an acid-binding agent to generate polysulfone; wherein the N-methyl pyrrolidone contains N-methyl pyrrolidone peroxide, and the molar content of the N-methyl pyrrolidone peroxide in the N-methyl pyrrolidone is less than or equal to 0.05%. The polysulfone with stable color and reduced yellowness value can be synthesized by controlling the content of peroxide impurities in the N-methyl pyrrolidone.

The low-pressure reverse osmosis membrane comprises a non-woven fabric base material, a polysulfone porous supporting layer and a polyamide functional layer. According to the low-pressure reverse osmosis membrane, the non-woven fabric base material is adopted for providing basic support, the polysulfone porous supporting layer has proper thickness and pore diameter, and a stable and transparent supporting structure is established for the polyamide functional layer. Nano titanium dioxide particles are introduced into the polyamide functional layer, and the particle size and the content of the nano titanium dioxide particles and the thickness and the surface carboxyl density of the polyamide functional layer are accurately controlled. Nano titanium dioxide particles are uniformly dispersed in a polyamide network, so that the hydrophilicity and surface charge distribution of a separation layer are effectively improved, and the resistance of water molecules passing through the membrane is reduced, thereby realizing high water flux; meanwhile, the structural stability of the polyamide composite layer is enhanced, and the mechanical strength and pollution resistance of the membrane are improved. Charge distribution and hydrophilicity on the surface of the membrane are adjusted by proper carboxyl density, water molecules are promoted to quickly pass through, solutes such as salt are effectively intercepted, and high desalination rate is realized.