971results about How to "Increase water flux" patented technology

The invention belongs to the technical field of membrane preparation and water purification and discloses a high-performance two-dimensional layered Ti3C2-MXene membrane, a preparation method thereof and an application of the Ti3C2-MXene membrane in water treatment. The method comprises steps as follows: (1), Ti3AlC2 powder and an HF solution are mixed, stirred for a reaction, centrifugally washed and dried, and Ti3C2 powder is obtained; (2), the Ti3C2 powder and a solvent are mixed, stirred for the reaction, washed and dried, and treated powder is obtained; (3), the treated powder is dissolved in the solvent and subjected to ultrasonic treatment and centrifugation, a liquid supernatant is taken and dried, and a two-dimensional nanosheet is obtained; (4), a solution is prepared from the two-dimensional nanosheet and deposited on a porous substrate with a nano self-assembly technology, and the high-performance two-dimensional layered Ti3C2-MXene membrane is obtained. The membrane has ultrahigh water flux, higher selectivity and good mechanical property and stability; the method is simple, low in energy consumption and cost, good in repeatability and wide in applicability.

The invention discloses a super-hydrophilic and underwater-super-oleophobic oil-water separation mesh membrane, and a preparation method and an application thereof. According to the method, fabric mesh with a specification of 100-300 meshes is subjected to ultrasonic cleaning, and is air-dried under normal temperature; a hydrophilic polymer water-sensitive agent and a cross-linking agent are dissolved in water according to a ratio of 1:9-9:1; the mixture is well mixed by magnetic stirring, such that a solution with a concentration of 1-99% is prepared; nano-sol is prepared with a sol-gel method; the solution and the nano-sol are prepared into a mixed solution with a concentration of 1-99%, and the solution is well dispersed through ultrasonic dispersion; the mesh is soaked in the mixed solution and is vertically lifted, or the mesh is directly sprayed by using a high-pressure spraying gun; and the mesh is bake-dried, such that the super-hydrophilic and underwater-super-oleophobic oil-water separation mesh membrane is obtained. Contact angles of the super-hydrophilic and underwater-super-oleophobic oil-water separation mesh membrane with water and oil in air are both 0 DEG, and the membrane is super-hydrophilic. Under water, the contact angle of the membrane with oil drops is larger than 150 DEG, and the membrane has an oil drop low adhesion characteristic. The mesh membrane provided by the invention can be used in oil-water mixture separation and oil-containing sewage processing.

The invention relates to a hyperfiltration membrane or nanofiltration membrane with a multi-layered composite structure and a preparation method thereof. The hyperfiltration membrane or nanofiltration membrane is a polymer electrostatic spinning nanofiber membrane layer characterized in strong chemical resistance prepared through an electrostatic spinning method, a hydrophilic polymer ultra-thin separation layer obtained through interfacial polymerization, and a functional group surface modification functional layer formed through the grafting reaction of reactant gases on the surfaces of hydrophilic polymers, or a long-chain polymer surface modification functional layer formed through the grafting reaction of the reaction gases on the surfaces of the hydrophilic polymers, or a functionalgroup-containing long-chain polymer surface modification functional layer through the grafting reaction of the reaction gases with the functional groups on the surfaces of the hydrophilic polymers. The hyperfiltration membrane or nanofiltration membrane with the multi-layered composite structure has the advantages of high water flux, high cutting rate and stable chemical performances. The filtration membrane can be used for the production of domestic water, drinking water or water in special conditions, and is suitable for the medical field, food field, environmental protection field and the like.

The invention belongs to the technical field of ceramic films, and in particular relates to a preparation method of a large-size thin-wall hollow flat-plate ceramic film. The preparation method comprises preparation of a flat-plate ceramic supporting body and preparation of a separation film layer. According to the preparation method, an alpha-Al2O3 powder body is coated by nano silicon dioxide dispersing liquid, so that the sintering temperature of the flat-plate film supporting body is greatly lowered, and the production energy consumption of a product is reduced; furthermore, chemical components of the supporting body are relatively high in purity, and the acid-alkali corrosion resistance is high; in a process of preparing a large-size thin-wall flat-plate film, deformation of a flat-plate film blank in extrusion, drying and sintering processes can be greatly reduced, and the yield of the flat-plate film is increased; the separation film layer adopts ceramic powder body particles modified by nano-silica sol; the surfaces of the particles are rounded and spheroidized; a duct of the prepared separation film layer is smooth and is low in filtering resistance; the water flux can be increased by over 30 percent.

The invention discloses a cellulose acetate nanofiltration membrane and a preparing method thereof. The preparing method of the cellulose acetate nanofiltration membrane includes the steps that cellulose acetate serves as a raw material, an organic metal framework compound and a small molecule pore-forming agent serve as a mixed additive, the raw material and the mixed additive are dissolved through a solvent to prepare a cellulose acetate membrane casting solution, a dry and clean glass plate with a supporting layer is coated with the prepared membrane casting solution to form a plate nascent-state membrane or the prepared membrane casting solution and a medium with an inner fiber cavity are extruded through a spinneret plate to obtain a hollow fiber nascent-state membrane, the hollow fiber nascent-state membrane is solidified and subjected to heat treatment, and the cellulose acetate nanofiltration membrane is prepared. As the cellulose acetate nanofiltration membrane is prepared through the organic metal framework compound, the porosity factor of the cellulose acetate nanofiltration membrane is increased, and the water flux is improved; the amine-modified organic metal framework compound is introduced into the formula of the membrane casting solution of the cellulose acetate, the nanofiltration membrane can show charged positive electricity after cross-linking, separation of amino acid with positive charges and protein with positive charges can be promoted, and the reject rate of the nanofiltration membrane is increased.

The invention relates to a method of the technical field of environment protection and in particular to a high salinity wastewater treatment corrosion-resistant anti-fouling membrane as well as a preparation method and application thereof. The preparation method comprises the following steps: by taking a mixture of clay minerals and oceanic nodule minerals as inorganic nano particles, modifying the inorganic nano particles with dopamine, and combining a PVDF (Polyvinylidene Fluoride) polymer with the nano particles, thereby obtaining the high salinity wastewater treatment corrosion-resistant anti-fouling membrane. The invention aims to improve the water flux, the corrosion resistance and the pollution resistance of the membrane, the mixture of the clay minerals and the oceanic nodule minerals is adopted as the inorganic nano particles, the inorganic nano particles are subjected to surface modification with dopamine, combination of the nano particles and the PVDF is promoted, the obtained membrane is capable of efficiently treating high salinity wastewater and meanwhile has properties of corrosion and fouling resistance; in addition, the dopamine has a great amount of hydrophilic groups of amino, particle aggregation is prevented, the hydrophilcity of the membrane is improved, and the difficulties that materials are not uniformly dispersed and are easily dropped off in the use process are solved.

The invention discloses a polymer / graphene hybridization nanofiltration composite membrane and a preparation method of the polymer / graphene hybridization nanofiltration composite membrane. The nanofiltration composite membrane is formed by forming a layer of polymer functional cortex containing graphene on a polysulfone porous support membrane through an interface polymerization technique. The graphene is effectively introduced into the functional cortex of the nanofiltration membrane by using the unique two-dimensional nanopore structure and good molecular mass transfer channel effect of the graphene, so that the performance of the nanofiltration composite membrane can be improved.

The invention discloses a novel composite forward osmosis membrane and a preparation method thereof. The preparation method comprises the following steps: coating a casting solution on a low-density non-woven fabric and carrying out phase inversion in a gel bath so as to obtain a porous supporting layer; and allowing an aqueous solution of polyamine and an organic solution of polyacyl chloride to react on the porous supporting layer to form an ultrathin separating layer so as to obtain the composite forward osmosis membrane with a three-layer structure consisting of a low-density non-woven fabric layer, the porous supporting layer and the ultrathin separating layer. According to the invention, through hydrophilic modification of the porous supporting layer and modification of the ultrathin separating layer on the surface, the thickness of the compact ultrathin separating layer is reduced, and water flux is improved. The novel composite forward osmosis membrane prepared in the invention can be used in the process of forward osmosis and has high membrane flux and a high retention rate.

The invention discloses an oxidized graphene metal / metallic oxide nanoparticle modified hollow fiber ultrafiltration membrane, and a preparation method thereof. According to the preparation method, anchoring of metal / metallic oxide nanoparticles on oxidized graphene is carried out; an obtained oxidized graphene dispersion liquid loaded with the metal / metallic oxide nanoparticles is added into a membrane material, and a membrane casting solution is obtained via mixing; the membrane casting solution is subjected to weaving so as to obtain the oxidized graphene metal / metallic oxide nanoparticle doped hollow fiber ultrafiltration membrane. Mechanical strength, water flux, retention rate, hydrophilic performance, pollution resistance, and service life of the hollow fiber ultrafiltration membrane are improved obviously; the preparation method is simple; operation is convenient; and repeatability is high.

The invention discloses a preparation method of a novel MOFs-PVDF (Metal-Organic Frameworks-Polyvinylidene Fluoride) composite film. The preparation method is mainly characterized in that a synthesizing environment of MOFs is controlled to be consistent with a casting solution preparation condition, an organic ligand and metal ions are added into a casting solution by a simple one-step synthetic method, intermolecular acting force between the organic ligand and PVDF is regulated and controlled, the PVDF is chemically combined with the MOFs through a hydrogen bond of an 'F' atom, chemical bonding of a PVDF polymer and the MOFs is realized, and an MOFs-PVDF polymer is synthesized in the casting solution, so that the formation of a chemical bonding hole and the formation of an MOFs-PVDF novel film are performed simultaneously in a spinning process. The method is easy and efficient; moreover, the prepared film combines the advantages of an MOFs and PVDF composite film; the prepared novel MOFs-PVDF composite film has the advantages of high chemical stability, high mechanical strength, controllable aperture, large surface specific area and high porosity.

The invention relates to a composite ultrafiltration membrane of a modified chitosan composite electrostatic spinning nanofiber. The composite ultrafiltration membrane is structurally characterized in that a non-woven fabric supporting layer substrate is sequentially provided with a membrane layer which has excellent chemical resistance and ageing resistance, and is composed of polymer electrostatic spinning nanofiber and prepared by using an electrostatic spinning method; and the surface of the membrane layer is an ultrathin modified chitosan separation layer which has high water permeability and stable chemical property, and is formed after a high-hydrophilcity ultrathin chitosan layer coated on the surface of the membrane layer composed of the polymer electrostatic spinning nanofiber by using aldehyde and acyl chloride modifiers is subjected to crosslinking modification. The multi-layer composite ultrafiltration membrane provided by the invention has the characteristics of high water flux, high interception efficiency, low pollution, resistance to acid and base and the like. The filtration membrane can be used for producing domestic water, drinking water and water used under special conditions and is suitable for the fields such as medicines, bioengineering, foods, environment friendliness and the like.

The invention discloses a method of atmospheric dielectric barrier discharge plasma to carry out polymer microporous membrane hydrophilic modification. The method comprises the following steps: (1) the polymer microporous membrane is cleaned clearly, dried and then arranged into the solution of an organic monomer for dipping; after the surface of the microporous membrane absorbs the organic monomer, the microporous membrane is taken out and aired; (2) the polymer microporous membrane treated by the step (1) is arranged between the two discharge electrodes of the dielectric barrier discharge to carry out atmospheric dielectric barrier discharge plasma treatment; (3) the polymer microporous membrane treated by step (2) is cleaned and then dried. The method has the characteristics of simple technique, convenient operation, quick processing speed, good and durable processing effect, low cost, being not easy to cause environment pollution, energy saving, and the like.

The invention discloses a polypropylene hollow fiber microporous membrane and a preparation method thereof. The hollow fiber microporous membrane comprises the following components in percentage by weight: 15-45% of polypropylene, 50-80% of thinner and 0.1-5% of additive. The preparation method of the hollow fiber microporous membrane is realized on the basis of a thermotropic phase separation process. The preparation method of the polypropylene hollow fiber microporous membrane is simple and easy to industrialize, and has low requirements on equipment, the prepared hollow fiber microporous membrane has the advantages of high strength, uniform pore diameter distribution, high porosity and the like, the pore diameter of the hollow fiber microporous membrane can be controlled between 0.1 and 0.45mu m, and the porosity is 60-85%, so the hollow fiber microporous membrane has large water flux, is not easy to block in use, can be widely used for feeding water treatment, and is particularly suitable for the membrane bioreactor technology and other water treatment fields.

The invention relates to a polyvinylidene fluoride microporous film preparation method by thermally induced phase separation, particular to a polyvinylidene fluoride microporous film preparation method by mixing the high temperature solvent and nonsolvent of the polyvinylidene fluoride in certain proportion to form a compound thinner. The method includes the following steps: polyvinylidene fluoride with the mass percentage of 20-60% and a corresponding compound thinner with the mass percentage of 80-40% are added into a stirring kettle, high-temperature digestion and standing deaeration are carried out in sequence to obtain homogeneous casting solution; the casting solution is directly coated on a supporting net by direct knifing to be planar or is spun by a spinneret to be hollow fibrillar, then the casting solution is dipped into cooling fluid for split phase solidification; and the thinner contained in solidification products is extracted, thus obtaining the polyvinylidene fluoride microporous film. The polyvinylidene fluoride microporous film prepared by the invention is high in film strength and large in water flux with the sections which have a uniform and run-through spongelike structure.

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 invention provides a compound having a structure shown as a formula (I) and a preparation method thereof. The invention further provides a positive charged composite nanofiltration membrane, which comprises a polyacrylonitrile support layer and a functional layer compounded on the surface of the polyacrylonitrile support layer, wherein the functional layer is a polymer of the compound having the structure shown as the formula (I) and piperazine. The invention further provides a preparation method of the positive charged composite nanofiltration membrane. The positive charged composite nanofiltration membrane, provided by the invention, represents electropositivity, not only has higher membrane flux, but also has higher rejection for calcium ion, magnesium ion and other positive ions. Furthermore, the preparation method provided by the invention has the advantages of simple process, wide source of raw materials and great easiness in implementing industrial production. Experiments show that the positive charged composite nanofiltration membrane prepared according to the preparation method disclosed by the invention has the water reflux as high as 50L / m2h and the rejection for calcium ion, magnesium ion and other positive ions as high as 95%.

The invention discloses a hydrophilic polyvinylidene fluoride modified separation membrane and a preparation method thereof. The separation membrane is prepared from polyvinylidene fluoride, a polyvinylidene fluoride solvent, a carbon oxide carbon nano tube / graphene oxide and a pore-forming agent. According to the hydrophilic polyvinylidene fluoride modified separation membrane, on one hand, hydrophilicity of the separation membrane is enhanced through oxygen-containing functional groups in the carbon oxide carbon nano tube and graphene oxide, on the other hand, graphene oxide of a sheet structure enters a carbon oxide carbon nano tube network of a tubular structure for mutual intercalation to form a stable sandwich layered structure, therefore, agglomeration of the same nano structure bodies can be effectively inhibited, and migration and assembly of graphene oxide to the surface of a composite membrane are facilitated, and the contact area of the carbon oxide carbon nano tube and graphene oxide and macromolecule matrix in the composite membrane is remarkably improved, and thus, the hydrophilicity and anti-pollution capacity of the membrane are enhanced, so that the water flux of the membrane is substantially improved. In addition, the preparation method is simple in operation technology and is easily carried out.

The invention discloses a method for preparing slab-shaped complex film made by blending polyethersulfone. Various film-forming agents according to certain proportion are made by blending polymer (polyethersulfone and sulfonated polyethersulfone), additive, non-solvent and organic solvent. Complex film is prepared on traditional shearing machine via pouring film-forming agents into loading chute, entering knife-edge groove, covering solution on supporting layer and dipping it into coagulating bath. The invention is characterized in that mainly via adjusting composition of film-forming agents, it prepares slab-shaped complex film with high intensity, high water flux and good hydrophilicity.

The invention provides a preparation method and application of a separation film with a nano composite cortical layer. The separation film comprises a non-woven fabric layer, two porous support layers and a desalination layer, and is characterized in that the lower layer of the two porous support layers is a porous body layer containing polymers and / or nano particles, and the upper layer of the two porous support layers is a porous cortical containing polymers and nano particles. The preparation method includes coating the upper layer and the lower layer of the non-woven base material by means of a double-layer coating technology. An ultrafilter support layer of the composite separation film prepared by the preparation method is good in surface evenness, hight water flux is kept in the meantime of keeping higher cutoff rate, and the separation film can be directly used as an ultrafiltration film or can be used as a basic porous support layer to further prepare a composite forward osmosis, reverse osmosis and nanofiltration film. The preparation method can be applied to preparing the reverse osmosis film and the nanofiltration film which are good in performance, and a composite ultrafiltration film with low molecular weight cutoff.

The invention discloses a super-hydrophilic and underwater super-oleophobic oil-water separation mesh film and a preparation method thereof. The method comprises the following steps: ultrasonically cleaning a fabric silk screen and airing at normal temperature; preparing polymer emulsion particle microspheres of which the particle size distribution is 100-500nm and the surface is rich in carboxyl salt by adopting an emulsion polymerization, and preparing nano-silica sol by adopting a sol-gel method; preparing hydrophilic emulsion particles and the nano sol into a mixed solution and performing uniformly ultrasonic dispersion; immersing the silk screen into the mixed solution, vertically lifting up, or directly spraying by adopting a high-pressure spray gun, and drying to obtain the super-hydrophilic and underwater super-oleophobic oil-water separation mesh film. The surface of the oil-water separation mesh film has a spherical rough micro-nano binary structure, contact angles with water and oil in air are 0 degree, and the oil-water separation mesh film has the super hydrophilicity. A contact angle with oil drops under water is larger than 150 degrees, and the oil-water separation mesh film has low adhesion properties on the oil drops. The mesh film can be applied to separating oil water mixtures and treating oily sewage.

The invention discloses a high-performance flat plate type cellulose acetate / nano-titanium dioxide blended forward osmosis membrane, which is prepared by comprising the following steps: adding the following raw materials in percentage by weight: 7.0%-26.0% of cellulose acetate, 2.0%-16.0% of additives, 0.1%-5.0% of nano-titanium dioxide, 0.05%-0.1% of graphene, and a dimethylformamide or dimethylacetamide, N-methylpyrrolidine and acetone mixed solvent into a dissolving tank according to certain sequence, stirring and dissolving for 3-15h to be full and even at 25-90DEG C, thus obtaining blended forward osmosis membrane casting liquid; and preparing the high-performance flat plate type cellulose acetate / nano-titanium dioxide blended forward osmosis membrane on a supporting material by using a phase conversion method. According to the prepared forward osmosis membrane, 1M NaCl and deionized water are respectively taken as driving liquid and feed solution, the flux of pure water can reach more than 17.5L / m<2>.h during testing time of1h and the backward salt flux is less than 3.0g / m<2>.h.

The hydrophilic modification method of surface of ultrahigh molecular weight polyethylene microporous filtering membrane belongs to the field of ozone grafted ultrahigh molecular weight polyethylene microporous filtering membrane preparation technology. It is characterized by that it utilizes ozone to initiate graft reaction on the surface of microporous filtering membrane, it selects vinyl-acetic ester (VAc) as graft monomer, after graft reaction makes saponification hydrolysis to form polyvinyl alcohol (PVA) hydrophilic group. The obtained microporous filtering membrane has good hydrophilic property and moisture absorbability.

The invention relates to an ultrafiltration membrane and a preparation method thereof, in particular to the ultrafiltration membrane with hydrophilism and antibacterial property and the preparation method thereof. The preparation method of the ultrafiltration membrane comprises the following steps: (1), adding certain amount of antibacterial agents into organic solvent, after completely dispersing, and then adding dry polymer, dissolving in the organic solvent, and adding a pore-foaming agent, stirring and dissolving the pore-foaming agent in constant temperature, forming polymer / solvent / pore-foaming agent ternary membrane casting solution, closely standing and defoaming at certain temperature, and acquiring the required membrane casting solution; (2), using a phase converting method to manufacture membranes, after filtering the membrane casting solution which is completely defoamed, using a membrane-scraping device to scrape on non-woven fabrics, using the phase converting method to form the membranes, and preserving the membranes in a wet state; relative humidity of a membrane manufacturing room is controlled in 45%-50%, and the temperature of the membrane manufacturing room is controlled in 25 DEG C-30 DEG C. The membranes manufactured by the preparation method of the ultrafiltration membrane with hydrophilism and antibacterial property has the advantages of being strong in antibacterial ability and anti-protein pollution, high in separation efficiency, large in water flux, and capable of being used in protein concentration or wastewater treatment in industry.

The invention relates to a preparation method for a polydopamine-modified polyamide composite forward osmosis membrane. The preparation method comprises the following steps: (1) a supporting layer is prepared; (2) the surface of the supporting layer is modified by polydopamine coating; (3) a polyamide separation layer is prepared on the surface of the modified supporting layer, and thereby the polydopamine-modified polyamide composite forward osmosis membrane is obtained. The polydopamine-modified polyamide composite forward osmosis membrane prepared by the preparation method has the advantages of hydrophilcity, large pure water permeation flux and small reverse salt diffusion flux, and is applicable to the field of water treatment such as sea water desalination.

The invention discloses a method for preparing a contamination-resistant composite reverse osmosis membrane. The method comprises the steps of (a) preparing a polysulfone support membrane; (b) preparing an aromatic polyamide reverse osmosis composite membrane by using the polysulfone support membrane obtained in Step (a); and (c) grafting chitosan on the surface of the aromatic polyamide reverse osmosis composite membrane obtained in Step (b). According to the method for preparing a contamination-resistant composite reverse osmosis membrane, chitosan is grafted on the surface of the polyamide reverse osmosis composite membrane through a chemical treatment method, so that hydrophilicity of the surface of the membrane as well as the water flux of the membrane is improved; meanwhile, contaminations such as hydrophobic organic matters and transition metal ions can be prevented from being absorbed on the surface of the membrane, thereby greatly improving the anti-pollution capability of the membrane; in addition, chitosan has broad-spectrum antibacterial property, so that the resistance of the membrane against microbial contamination is improved.

The invention discloses a reverse osmosis membrane and a preparation method thereof. The reverse osmosis membrane comprises a non-woven support layer, a polysulfone base membrane layer, a polyamide desalination layer and a transition layer, wherein the non-woven support layer is coated with the polysulfone base membrane layer; the transition layer is a hydrophilic membrane layer and is arranged between the polysulfone base membrane layer and the polyamide desalination layer. According to the reverse osmosis membrane, as the hydrophilic transition layer is inserted between the polysulfone base membrane layer and the polyamide desalination layer, the hydrophilic transition layer improves dispersion uniformity of a polyamine solution on the surface of the polysulfone base membrane layer, a binding force of the hydrophilic polyamide desalination layer with the polysulfone base membrane layer is increased greatly, the reverse osmosis membrane is high in desalinization ratio, uniformity and water flux, and long in service life, and can bear at least 0.5 MPa backpressure, and significantly lower engineering cost and manufacturing cost.

The invention discloses a double-layer composite hollow fiber nano-filtration membrane and preparation method and special tool thereof, wherein the nano-filtration membrane comprises a selective separating outer sheath layer and a mechanical inner supporting layer; the selective separating outer sheath layer with the thickness of 10-10000 nm is provided with the membrane holes with the hole diameter of 0.5-2 nm, wherein the thickness of the mechanical inner supporting layer is 1-3mm; the selective separating outer sheath layer and the mechanical inner supporting layer of the double-layer composite hollow fiber nano-filtration membrane are respectively dissolved into the solvent through the high polymer of the selective separating outer sheath layer and the high polymer of the mechanical inner supporting layer. The invention can control the thickness of the selective separating outer sheath layer to be 10-100 nm, thereby greatly reducing the materials of the selective separating outer sheath layer and greatly lowering the cost. The invention effectively controls the internal / external diameter of the membrane, the effective hole diameter of the membrane, the hole rate and the hole diameter distribution by controlling the components of the liquid materials, the spinning condition, the condensing bath and the post processes so as to obtain the high effective separating membrane provided with the good hydrophilic performance, pollution proof and large water flux.

The invention discloses a polysulfonamide nanofiltration or reverse-osmosis composite membrane, and a preparation method thereof. the preparation method for the polysulfonamide nanofiltration or reverse-osmosis composite membrane comprises the following steps: pretreatment of a porous supporting membrane; alternate layer-upon-layer assembling of a sulfonyl chloride organic-phase solution and a polyamine water-phase solution on the surface of the porous supporting membrane via reaction; heat treatment; etc.; wherein heat treatment can be carried out during or after layer-upon-layer assembling. Nanoparticles, a surfactant, a catalytic acid absorbent or catalyst, a pore forming agent and other additives are added into the sulfonyl chloride organic-phase solution and the polyamine water-phase solution. The polysulfonamide nanofiltration or reverse-osmosis composite membrane prepared by using the method has improved desalination performance and acid resistance, smoother surface and lower roughness compared with composite membranes prepared through traditional interfacial polymerization, and has good application prospects in the fields of nanofiltration and reverse osmosis.

The invention discloses a pollution-resistant polyamide composite membrane which comprises a nonwoven fabric layer, a porous support layer, a polyamide layer and a pollution-resistant layer which are stacked sequentially, wherein the pollution-resistant layer comprises a polymer compounding inorganic nano particles; the inorganic nano particles are modified or unmodified inorganic nano particles, and preferably are at least one kind of the nano particles of silver, silver compound, modified silver, modified silver compound, copper, copper compound, modified copper, modified copper compound, zinc, zinc compound, modified zinc, modified zinc compound, titanium, titanium compound, modified titanium and modified titanium compound. The invention also provides a preparation method of the pollution-resistant polyamide composite membrane and an application of the pollution-resistant polyamide composite membrane in the field of liquid separation.

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.