66results about How to "High Salt Rejection" patented technology

A reverse osmosis composite membrane that has a high salt rejection, a high water permeability, and a high fouling tolerance, and permits practical desalination at a relatively low pressure is provided by coating the surface of a reverse osmosis membrane of aromatic polyamide with polyvinyl alcohol (PVA), for example, and controlling the surface zeta potential of the separation layer within±10 mV at pH 6. This reverse osmosis composite membrane is electrically neutral and controls the electrical adsorption of membrane-fouling substances having a charge group present in water. Therefore, a high separation property can be maintained without fouling the membrane even if water containing a surfactant or a transition metal component is supplied as raw water.

The invention provides a preparation method of an amino-modified graphene oxide composite positive permeable film. The method is characterized by comprising the following specific steps: mixing graphene oxide, dimethyl formamide, organic amine and dicyclohexyl carbimide, and performing ultrasonic treatment; reacting for 40-50 hours at the temperature of 100-150 DEG C; adding absolute ethyl alcohol, and standing and filtering to obtain a precipitate; washing and drying the precipitate to obtain amino-modified graphene oxide; mixing the amino-modified graphene oxide with a solvent, performing ultrasonic treatment, and adding an additive and a film formation polymer into a mixed solution to prepare a casting film solution; de-foaming to prepare a base film through a phase inversion method, and immersing the base film in pure water for later use; and pouring a metaphenylene diamine solution and trimesoyl chloride to the surface of the base film, performing a contact reaction, washing the surface of the film with an organic solvent, and drying the film to obtain the amino-modified graphene oxide composite positive permeable film. The amino-modified graphene oxide composite positive permeable film is high in mechanical strength, high in chemical stability, large in permeation flux of the pure water, and high in salt rejection rate.

The invention discloses a high-temperature resistance polyamide composite membrane and a preparation method thereof. The high-temperature resistance polyamide composite membrane is composed of a non-woven fabric layer, a porous supporting layer and a polyamide layer, wherein a porous supporting membrane material is prepared by adding one or more of a solubility high-temperature resistance polymer P1 and a commodity polymer P2 for preparation of a porous membrane material to a certain solvent and a pore-foaming agent and at least contains the P1. The polyamide composite membrane prepared by the method has very good high-temperature resistance performance and can be widely applied to water treatment composite membrane treatment devices needing to run at a high temperature in industries such as industrial wastewater treatment, petrochemical wastewater treatment, food, medicines and the like.

The invention relates to a method for preparing a polyvinylidene fluoride composite cellulose acetate forward osmosis membrane. The conventional product has a serious inside concentration polarization phenomenon and low actual flux. The method comprises the following steps of: preparing a polyvinylidene fluoride cast membrane solution from polyvinylidene fluoride and additive; preparing a cellulose acetate cast membrane solution from cellulose acetate, cellulose triacetate and molecular sieve; and uniformly coating the polyvinylidene fluoride cast membrane solution on a non-woven fabric to obtain a hydrophilic polyvinylidene fluoride micro-filtration base membrane, drying or naturally drying in air to form a dry hydrophilic polyvinylidene fluoride membrane, uniformly coating the cellulose acetate cast membrane solution on the dry hydrophilic polyvinylidene fluoride membrane, and thus obtaining the composite forward osmosis membrane. The forward osmosis membrane prepared by the method has high mechanical strength and solvent tolerance, high water flux and high salt intercepting rate, and can be applied in the fields of desalting of seawater and brine, softening of hard water, first-aid water bags and the like.

The present invention relates to systems, methods and uses for recycling at least a part of water lost during various renal replacement therapy processes, e.g. in the preparation of a fresh dialysate solution or fresh reconstitution fluid for kidney disease dialysis and hemofiltration by utilizing water from the spent fluids. The system of the invention is useful in hemodialysis and in peritoneal dialysis as well as in hemofiltration for reuse of water from filtrates and spent fluids. In addition, the system of the invention is useful in the development of a renal assist device or artificial kidney.

The invention discloses a preparation method of an alumina/oxidized graphene/polyvinyl alcohol composite nanofiltration membrane. The preparation method comprises following steps: Hummers method is adopted to prepare oxidized graphene, homogeneous precipitation method is adopted to cover an formed oxidized graphene layer with an amorphous nanometer alumina thin layer uniformly so as to obtain a monomer used for layer by layer self assembling; polyethersulfone is taken as a substrate, is coated with a layer of polyvinyl alcohol, and is coated with a layer of the nanometer alumina/oxidized graphene composite monomer, alternative coating of the above two monomers is carried out so as to obtain the nanometer alumina/oxidized graphene/polyvinyl alcohol composite nanofiltration membrane. The surface of the nanometer alumina/oxidized graphene/polyvinyl alcohol composite nanofiltration membrane contains a large amount of hydrophilic groups such as hydroxyl and carboxyl, so that pure water flux is high; and at the same time, the film surface is negatively charged, so that film layer salt retention rate is increased.

The invention relates to a preparation method of a hydrophilic anti-pollution aromatic polyamide reverse-osmosis membrane, and belongs to the technical field of modification preparation of high-performance reverse-osmosis membranes. The preparation method includes the following steps that a polysulfone-base membrane is soaked in deionized water, then blow-dried, and fixed in a polytetrafluoroethylene frame, and a water solution of m-phenylenediamine and dimethyl diallyl ammonium chloride is poured onto the surface of the polysulfone-base membrane; an n-hexane solution of trimesoyl chloride isthen poured for an interface polymerization reaction; a water solution of hydrophilic olefin type monomers is poured onto the surface of the membrane, irradiation treatment is conducted with gamma-rays, and a modified membrane is obtained; the modified membrane is cleaned and dried. The preparation method has the advantages that macromolecule hydrophilic dimethyl diallyl ammonium chloride is grafted onto the surface of a polyamide separation layer, accordingly, good hydrophilicity is realized, the overall roughness of the surface of the reverse-osmosis membrane is reduced, and depositing and adsorbing of contaminants on the surface of the membrane can be reduced. Meanwhile, the macromolecule hydrophilic dimethyl diallyl ammonium chloride is grafted onto the surface of the polyamide separation layer to form a specific water channel, and therefore the performance of the reverse-osmosis membrane is improved.

The invention relates to an amphoteric composite forward osmosis membrane. According to the amphoteric composite forward osmosis membrane, an adopted porous support membrane is a super-hydrophilic polyvinylidene fluoride membrane; a polyamide layer is formed on the porous support membrane, and a zwitterionic layer is formed on the polyamide layer. In the present invention, the zwitterionic layer is formed by amido groups through zwitterionic reaction; through cooperation with the super-hydrophilic characteristic of the polyvinylidene fluoride membrane prepared through water vapor induced phaseseparation, the strong hydration and the charging performance of a catechol derivative modified graphene oxide nano-water channel and the zwitterionic skin layer, the water flux of the composite forward osmosis membrane is greatly improved while a low back-mixing salt flux is kept.

The invention discloses metal-organic framework nanosheet modified forward osmosis film and a preparation method and application thereof. metal-organic framework nanosheets are introduced to an interfacial polymerization process for active layer preparation; a polyamide active layer containing metal-organic framework nanosheets is formed in situ on a support layer. An organic ligand to synthesizethe metal-organic framework nanosheets is terephthalic acid so that the metal-organic framework nanosheets have excellent hydrophilicity; compared with traditional inorganic nano materials, the metal-organic framework nanosheets are well compatible with polyamide film; extra pores are provided for mass transfer of the forward osmosis film polyamide active layer; water flux of the film can be further increased in the actual forward osmosis process; a higher water flux is attained under equal osmotic pressure, salt return mixing amount is lower, and anti-pollution performance is good.

The invention discloses a preparation method of a forward osmosis membrane based on a 3D printing technology. The method comprises the following steps: (1) preparing a polyvinyl chloride supporting layer: mixing polyvinyl chloride, polyvinyl alcohol and N-methylpyrrolidone until the three substances are evenly stirred, standing the obtained mixture to defoam, uniformly forming a membrane by usinga membrane coating machine, and storing the membrane in deionized water for later use; and (2) preparing a polyvinyl chloride-polyamide composite membrane: preparing an n-hexane solution A containingtrimesoyl chloride and an aqueous solution B containing m-phenylenediamine, and sequentially depositing the solution B and the solution A on the polyvinyl chloride supporting layer by a 3D printer toobtain the composite membrane. The positive osmosis membrane prepared by the 3D printing technology has a controllable pore size and a controllable thickness; and the surface roughness of the membraneis reduced to about 2 nm from original about 80 nm (the surface roughness of membranes prepared through conventional interfacial polymerization methods), so the composite membrane is thin and smooth,thereby the water permeability and the salt rejection rate are greatly improved, good performances of the membrane are ensured, and the cost is reduced.

The invention provides a preparation method of a composite nanofiltration membrane. A trace amount of carbachol is added as a functional reactive monomer to a piperazine-containing aqueous phase solution for interfacial polymerization, and effective regulation and control of a polypiperazine amide structure can be realized. The crosslinking degree of polyamide is improved and at the same time thethickness of a finally formed functional layer is reduced, so that a high-performance composite nanofiltration membrane with high water flux and high salt rejection is prepared. The method has the advantages of simple and convenient operation process, and the addition amount of carbachol in the aqueous phase is small and is non-irritating to the human body, and application prospects of the composite nanofiltration membrane in large-scale production is very broad.

The invention discloses a high-flux high-desalination-rate mixed matrix reverse osmosis membrane, and a preparation method and application thereof. The reverse osmosis composite membrane is composed of a polysulfone supporting membrane and a functional layer; the functional layer is prepared by taking m-phenylenediamine as a water-phase monomer, taking trimesoyl chloride as an oil-phase monomer and taking an acyl chloride group-terminated hyperbranched polymer as a doping material, and the functional layer is polymerized on the supporting membrane through interfacial polymerization. Accordingto the invention, a simple and feasible treatment process is used, and a hyperbranched polymer is selected to be functionalized, so that the hyperbranched polymer can participate in interfacial polymerization. Due to highly dendritic structure of the hyperbranched polymer, the hyperbranched polymer can be used for preparing the mixed matrix reverse osmosis membrane, so that the pore number of a polyamide layer of the mixed matrix reverse osmosis membrane is increased, mass transfer resistance of water is reduced, and thus the water flux of the prepared mixed matrix reverse osmosis membrane isimproved on the basis of maintaining a high salt interception rate.

The invention discloses a preparation method of a composite forward osmosis membrane with a Turing structure. The method includes the steps of: (1) preparation of sulfonated polysulfone: fully mixingsulfonated polysulfone, 1, 2-dichloroethane and concentrated sulfuric acid to obtain a solid substance, washing the solid substance with deionized water and performing drying; (2) preparation of a sulfonated polysulfone support layer: mixing sulfonated polysulfone with N, N-dimethylformamide, then performing degassing, performing coating into a film and conducting cooling; and (3) preparation of asulfonated polysulfone-polyamide composite layer forward osmosis membrane: soaking a sulfonated polysulfone support layer in a mixed solution of m-phenylenediamine and polyvinyl alcohol, and conducting N2 purging; then placing the support layer in a mixed solution of trimesoyl chloride and n-hexane, and conducting drying and cooling. The existence of the Turing structure provides a lot of high water permeability sites to the forward osmosis membrane prepared according to the method, and the water permeability and salt retention rate of the membrane are greatly improved compared with the traditional forward osmosis membranes.

The invention belongs to the field of preparation of an inorganic membrane material, and especially relates to a sulfhydrylation-modified TRIES separating membrane and a preparation method and a purpose thereof. a TRIES sol is prepared by a sol-gel method, a support diaphragm of an alpha-Al2O3 material is coated with the TRIES sol, then is calcined under high temperature inert atmosphere to obtain the TRIES separating membrane, H2S and H2 mixing gas is introduced under high temperature condition, and in-situ sulfhydrylation modification is carried out for 1 hour to obtain the sulfhydrylation-modified TRIES separating membrane. The sulfhydrylation-modified TRIES separating membrane is used for the field of reverse osmosis desalination, and presents good separating performance.