177results about How to "Increased pure water flux" patented technology

The invention discloses a polyvinylidene fluoride hollow fiber film and a preparation method thereof. The polyvinylidene fluoride hollow fiber film comprises the following components by weight percent: 20-60% of polyvinylidene fluoride resin, 10-50% of organic pore-forming agent, 1-30% of inorganic pore-forming agent and 5-30% of solvent. The preparation method comprises the following steps: mixing, squeezing, cooling, stretching, extracting the organic pore-forming agent and the inorganic pore-forming agent, and thermally shaping. The obtained polyvinylidene fluoride hollow fiber film has the advantages of high strength, good performance, better hydrophilicity, simple preparation process and energy saving.

The invention discloses a preparation method of a layer-by-layer self-assembled hollow fiber forward osmosis membrane. The preparation method comprises the steps of: preparing hollow fiber forward osmosis base film, modifying hollow fiber ultrafiltration base film, repeating layer-by-layer assembly of polycation and polyanion layers, performing interface cross-linking polymerization for preparinga selective functional layer, conducting moisturizing, and carrying out treatment and storage so as to prepare the layer-by-layer self-assembled hollow fiber forward osmosis membrane. The surface of the hollow fiber self-support base film which is prepared by using a phase conversion method is activated firstly, layer-by-layer assembly of polycation and polyanion is repeated on the surface of thefilm so as to form an functional polarization layer for an electrolyte solution, and the polyamide selective layer is prepared through interfacial chemical cross-linking polymerization. The prepared hollow fiber forward osmosis membrane has a controllable thickness and an internal polarization layer with a high charge capacity, and the internal concentration polarization phenomenon can be alleviated effectively during the forward osmosis process; therefore, the hollow fiber forward osmosis membrane can simultaneously obtain high flux and low reverse salt flux, has high filtration separation efficiency, easy cleaning and a long service life, and can be widely applied to seawater desalination and concentration and desalination of brine.

The present invention relates to a polyvinylidene flouride modified film and its prparation method. Said invention is prepared by using (by wt%) 14-20% of high-molecular material dissolved in organic solvent and adding 1-6% of organic additive, 0.01-4% of inorganic additive and 0.01-0.9% of titanuim dioxide, whose average grain size is 1-20 nm. Said invention improves the hydrophilic property of polyvinylidene flouride, and the pure water flux of said polyvinylidene flouride film can be raised.

The present invention discloses a plant polyphenol modified polymer membrane as well as a preparation method and application thereof, in particular relates to the field of modified polymer membranes with anti-fouling properties. In the prior art, due to low surface energy of the polymer membrane, the polymer membrane is susceptible to contamination with proteins, oils and the like and causes a series of temporary or permanent pollution problems. The polymer membrane provided by the invention utilizes the super-strong adhesive ability of plant polyphenols and the coordination of polyphenols andmetal ions to build a hydrophilic coating on the surface of a hydrophobic polymer membrane. The polymer membrane provided by the invention has the advantages of simplicity, high efficiency, mild reaction condition and strong practicability. The controllable hydrophilic modification of a hydrophobic polymer can be realized by changing the conditions of the dip-coating time, the concentration of aplant polyphenol mixed solution, the pH, the temperature and the like, and a high permeation flux can be maintained in the course of cross-flow continuous work, so that the polymer membrane has a verygood application prospect in the field of water treatment. The invention also opens up an effective way, which is simple and easy to operate and has strong universality, for modification of polymer membranes under mild conditions.

The invention belongs to the fields of material science and engineering, and particularly relates to a preparation method of a gradient silicon carbide ceramic membrane for water purification. The method comprises the following steps: (1) preparing a silicon carbide ceramic support body; (2) preparing a silicon carbide intermediate layer; and (3) preparing a silicon carbide film, and finally preparing the gradient silicon carbide ceramic membrane for the water purification. The method has the beneficial effects that the prepared silicon carbide ceramic membrane material is high in communicating porosity, high in strength, high in pure water flux, and high in strong acid and alkali resistance; the pore distribution is in a gradient shape, different levels of connection surface are high in bonding strength, the method is simple and convenient to operate, and the gradient silicon carbide ceramic membrane is high in yield. According to the prepared gradient silicon carbide ceramic membrane material for water purification, the breaking strength is greater than 30MPa, the pure water flux is greater than 5m<3>/(m<2>h), and the range tolerance of the pH value is 0-14.

The invention discloses a polyvinylidene-fluoride hollow fibre membrane and a preparation method thereof. Calculated according to parts by weight, the polyvinylidene-fluoride hollow fibre membrane is mainly prepared by the following components: 15 to 25 parts of polyvinylidene fluoride, 50 to 80 parts of solvent, 1 to 3 parts of surfactant, 2 to 12 parts of polymeric additive, 1 to 8 parts of inorganic additive and 1 to 12 parts of modified blend. By utilizing the simultaneous action of two modes of organic blending and inorganic adding according to the polyvinylidene-fluoride hollow fibre membrane and the preparation method thereof, the hydrophilcity of the polyvinylidene-fluoride hollow fibre membrane is obviously improved, and the pollution resistance can be obviously reinforced; and the pure water flux of the polyvinylidene-fluoride hollow fibre membrane is further enhanced by selecting and regulating the raw materials and the mixture ratio of the modified blend and the inorganic additive so as to obtain the permanently hydrophilic modified polyvinylidene-fluoride hollow fibre membrane.

The invention discloses a preparation method of a metal ion-carried nerchinskite nano tube/polyether sulfone hybridized antibacterial membrane, and belongs to the technical field of membranes. The invention is characterized in that: the antibacterial property and the contamination resistance of the membrane are improved by using the antibacterial property of a metal ion-carried nerchinskite nano tube and the hydrophilic property of the nerchinskite nano tube under the condition that the water flux and the interception rate of the polyether sulfone ultra-filtration membrane are not reduced. Meanwhile, the preparation method and preparation equipment are simple. The membrane serving as a novel ultra-filtration membrane is expected to be applied in wastewater treatment more widely.

The invention relates to a polyvinylidene fluoride/organic clay nano composite ultralow pressure ultrafiltration membrane and a preparation method thereof, and to a nano composite membrane and a preparation method thereof. The invention resolves the problem that the existing membrane material has a bad hydrophilicity and a low surface energy and is easily be polluted, and the existing modified method has the disadvantage that it can not run under ultralow pressure and the running cost is high. It is composed of 20-50 shares by weight of PVDF, 0.1-20 shares by weight of organic clay, 10-1000 shares by weight of disperse medium, 10-50 shares by weight of organic addition agent and 0.1-30 shares by weight of inorganic additive. The invention adds the organic clay, inorganic additive, organic addition agent and PVDF in turns into the disperse medium to get the casting film liquor after 3-48 hours dissolution and 5-24 hours stewing deaeration; plate membrane, tubular type membrane, hollow fibre membrane, and comparable membrane module can be prepared. The invention can change the hydrophilicity of the composite membrane, resolve the pollution of exiting membrane effectively, increase the water flux and retain ratio, extend the washing period, raise the treating capacity, and realize the large scale use and run in ultralow pressure.

The invention discloses a heavy metal ion adsorption type polyvinylidene fluoride (PVDF) hollow fiber membrane. The invention belongs to the technical field of membranes and in particular relates to a preparation technology for an organic-inorganic hybrid hollow fiber membrane. The heavy metal ion adsorption type PVDF hollow fiber membrane comprises modified attapulgite, wherein the mass ratio of the PVDF to the modified attapulgite is (1:0.01)-(1:0.1). The heavy metal ion adsorption type PVDF hollow fiber membrane has the advantages that high pressure resistance is achieved, a supporting body is not required, a membrane component has any sizes and shapes and large filling density, and unit volume membrane area and flux are large. In addition, the hybrid membrane is high in spinning performance, the spinning membrane-forming process is simple in process, and cost is low.

The invention relates to a polyvinylidene fluoride membrane. The membrane casting liquid comprises the following components in percentage by weight: 10-25% of polyvinylidene fluoride resin, 1-4% of diatomite, 1-5% of amphiphilic copolymer, 4-12% of organic pore-forming agent, 0.2-3% of inorganic pore-forming agent, 0.1-3% of surfactant and the balance of solvent. According to the polyvinylidene fluoride membrane, the diatomite and the amphiphilic copolymer are added; by virtue of the diatomite, the mechanical strength and pure water flux of the membrane are improved; the amphiphilic copolymer and polyvinylidene fluoride have good compatibility; the combination force is strong; the copolymer is unlikely to run off and the continuous hydrophily of the membrane is guaranteed. The invention further relates to a preparation method of the polyvinylidene fluoride membrane. The preparation method comprises the following steps: (1) uniformly stirring the membrane casting liquid, standing and defoaming; (2) enabling the membrane casting liquid to vertically flow in the air by virtue of a spinning spinneret, so that the membrane casting liquid enters the coagulating bath and is cured and formed; (3) soaking the spun and formed polyvinylidene fluoride membrane in pure water and a glycerol water solution in sequence and drying so as to obtain the polyvinylidene fluoride membrane.

The invention belongs to the technical field of membrane preparation, and particularly provides a MXene-based bismuth-based photocatalytic composite membrane which comprises an MXene nanosheet, bismuth-based photocatalytic nanoparticles and a porous support layer, wherein the bismuth-based photocatalytic nanoparticles grow on a single-layer MXene nanosheet in situ to form an MXene/bismuth-based photocatalytic nanoparticle composite material, and the MXene/bismuth-based photocatalytic nanoparticle composite material is prepared on the porous support layer; the membrane has good separation performance, and the pure water flux is increased by 2-23 times compared with that of a traditional polymer membrane on the premise that the rejection rate is kept; the membrane has excellent self-cleaningand anti-pollution performance, after the membrane performs a filtering experiment on dye molecules rhodamine B for 12 hours, the dye adsorbed on the membrane is degraded for 20 minutes by using simulated sunlight, and the water flux recovery rate of the membrane is as high as 97.6%; the preparation method of the MXene-based bismuth-based photocatalytic composite membrane is relatively simple, low in cost, time-saving and suitable for industrial expanded production.

The invention relates to a polyvinylidene fluoride (PVDF) hollow-fiber membrane with a base material, which has an average aperture of 0.03-0.5 micrometer, an inner diameter of 0.4-1.8 millimeters, an outer diameter of 1.1-4.5 millimeters, a strength of 200-500N and a pure water flux of 500-10,000L/m<2>/h at 25 DEG C under atmospheric pressure. The invention also relates to a production method of the hollow-fiber membrane with a base material, which can solve the essential problem of low gel efficiency of the PVDF hollow-fiber membrane with a base material (hollow-fiber rope) so as to solve the problems of poor membrane homogeneity, wide aperture distribution, low spinning speed, high production cost, and the like.

The invention discloses a high-strength and high-flux hollow fiber membrane and a preparation method thereof. The method is characterized by comprising the following main steps: taking ultrahigh molecular weight polyvinylidene fluoride as a raw material and adding nano-size inorganic additives, PVP (polyvinyl pyrrolidone) and a solvent to the raw material for mixing; using a single screw to transmit a feed liquid at the condition of even dissolving and high-speed stirring in a stirred tank; carrying out vacuum defoaming on one section of the single screw; using a metering pump and a spinning nozzle to extrude; and adopting acid or alkali to wash after the gel is coagulated in a gel groove, thus obtaining the high-strength and high-flux polyvinylidene fluoride hollow fiber membrane. The external diameter, the internal diameter and the bore diameter of a membrane wire of the high-strength and high-flux hollow fiber membrane are 1200 micrometer, 600 micrometer and 0.06-0.2 micrometer respectively, thus solving the problems that a hollow fiber membrane prepared by a traditional non-solvent phase separation method is low in strength and small in water flux.

A high-throughness separating PVC mixture membrane with high hydrophilicity is prepared through proportionally dissolving the polyvinyl alcohol, alkoholyzed halogene-fatty-acid-ene and PVC in organic solvent, adding additive, dissolving, ageing, doctor blading to form membrane, evaporating, and automatic stripping in gel bath.

The invention relates to a polyvinylidene fluoride (PVDF) hollow fiber membrane with a base material and a production method thereof. The average pore size of the membrane is 0.04-0.4mu m, the inner diameter and the outer diameter of the hollow fiber of the membrane are respectively 0.5-1.6mm and 1.0-4.0mm, the strength of the membrane is 100-300N, the wetting angle of the membrane is less than 60 degrees and the pure water flux under 25 DEG C and an atmospheric pressure is 100-400L/m2.h. The invention also relates to the production method of the hollow fiber membrane with the base material. The radical problems of poor hydrophilicity and low flux of the PVDF hollow fiber membrane with the base material (the hollow fiber rope) can be solved by the production method.

The invention discloses a preparation method of a nanometer composite forward osmosis membrane with organic silane grafted multi-wall carbon nanometer tubes embedded into a polyamide separation layer. The carbon nanometer tube is added into concentrated acid to obtain the carbon nanometer tubes with carboxyls on the surface; thionyl chloride is used for acyl chlorization on the carbon nanometer tubes; further, reaction is performed with organic silane containing amino groups or sulfydryls; the organic silane is grafted onto the carbon nanometer tubes; macromolecular membrane materials are prepared into a porous organic filtering membrane; a thin separation layer is polymerized on the surface interface of a support layer of the porous organic filtering membrane; the organic silane grafted carbon nanometer tubes are used as nanometer filling materials to be added into an oil phase; the organic silane grafted carbon nanometer tubes are embedded into a separation layer to obtain a target product. The method provided by the invention has the advantages that the water flux of the product is greatly improved; the reverse diffusion quantity of a draw solution solute is reduced; in addition, good anti-pollution capability is shown; the membrane belongs to a novel forward osmosis membrane with a wide application potential.

The invention discloses a polypropylene hollow fiber separating membrane and a preparation method thereof. The polypropylene hollow fiber separating membrane disclosed by the invention comprises the components of 10-40 percent of polypropylene resin and 60-90 percent of diluting agent, the melt index of the polypropylene resin used in the invention is 0.1-4g/10min, and the weight-average molecular weight of the polypropylene resin is 3*10<5>-1.2*10<6>. According to the polypropylene hollow fiber separating membrane, by using the polypropylene resin with high weight-average molecular weight, the concentration of a casting film solution can be reduced; the preparation method is convenient and simple to operate and easy to realize. The polypropylene hollow fiber separating membrane disclosed by the invention has the advantages of large micropores in the surface, large flux and higher porosity, and can be widely applied to the fields such as water treatment, membrane distillation, biology, medicines and energy sources, and is better in application prospect.

The invention discloses a positively charged composite nano filtration membrane. The nano filtration membrane is characterized in that a modified meta-aramid hollow fiber membrane is taken as a base membrane, an ultra-thin polyamide layer is formed by positively charged polyelectrolyte, polyamine and polyacyl chloride through interfacial polymerization, and a method for preparing the composite nano filtration membrane is prepared. According to the composite nano filtration membrane, pure water throughput under 0.3 MPa is greater than or equal to 24 L (m2 h), the desalting rate of 2g/L divalentcation salt solution is greater than or equal to 90%, the needed cost is lower, and industrialization is easy. The preparation method is simple, operation is easy, reaction conditions are mild, the performance is stable, and the market application prospects are wider.

The invention provides a preparation method for a polyisophthaloyl metaphenylene diamine nanofiltration membrane and belongs to the field of membrane pollution resistance. The method includes the steps that a fully-dried polyisophthaloyl metaphenylene diamine nanofiltration membrane is flatly laid on a glass plate, the glass plate is placed in a plate frame to be tightened, a prepared solution containing an acid binding agent is poured to the surface of the membrane for impregnation, the remaining solution is poured out, and the membrane is placed in a fume cupboard to be dried in shade; then a prepared crosslinking solution is poured to the surface of the membrane for impregnation, and the surplus solution is removed through a silica gel wheel; then an oxidized graphene solution is poured to the surface of the membrane for impregnation, the remaining solution is poured out, and the membrane is dried in shade; finally the treated membrane is placed within the temperature interval of 40-80 DEG C for heat treatment for 60-180 s, and the modified nanofiltration membrane is obtained. The technological operation is easy, the original excellent characteristics of the polyisophthaloyl metaphenylene diamine nanofiltration membrane are kept, the hydrophilia of the surface of the membrane is also well enhanced, the pollution resistance of the membrane is improved, and wide application prospects are achieved.

The invention discloses a composite nano-filtration membrane, wherein a modified meta-aramid hollow fiber membrane is used as a base membrane, and polyamine, a diaminobenzene fluoride and polyacyl chloride are subjected to an interface polymerization reaction on the base membrane to form an ultra-thin polyamide layer. The invention further provides a preparation method of the composite nano-filtration membrane. With the technical scheme of the present invention, the pure water flux of the prepared composite nano-filtration membrane is more than or equal to 50 L/(m<2>.h) at 0.5 MPa, the desalination rate of the prepared composite nano-filtration membrane to the 2 g/L divalent cation salt solution is more than or equal to 80%, the required cost is low, and the method is suitable for industrial production; and the preparation method has characteristics of simpleness, mild reaction condition, stable product performance and wide market application prospect.

The invention discloses a water-saving membrane component and a filter structure thereof. The water-saving membrane component comprises a center tube, a filter membrane component, an upper seal part and a lower seal part, and the filter membrane component is rolled centering on the center tube. The upper seal part seals the outer periphery of the upper end face of the filter membrane component to make the inner periphery, close to the center tube, of the upper end face, serve as a wastewater outlet. The lower seal part seals the inner periphery, close to the center tube, of the lower end face of the filter membrane component to make the outer periphery of the lower end face serve as a water inlet. Due to adoption of the water-saving membrane component, during filtering, raw water enters the outermost layer of the water-saving membrane component from the water inlet of the outer periphery of the lower end face and then spirally flows into the innermost layer of the water-saving membrane component from the outermost layer of the water-saving membrane component, pure water flows into the center tube, and waste water flows out from the wastewater outlet. The water-saving membrane component and the filter structure thereof have advantages of complete utilization of the filter membrane component, low loss, high pure water flux, less wastewater, uniformity in water feeding, long filter flow passage, effectiveness in filtration and the like.