Abstract: Disclosed are a nanofiltration composite hollow fiber membrane and a method of manufacturing the same. The nanofiltration composite hollow fiber membrane includes a reinforcement (1) which is a tubular braid, a polymeric resin thin film (2) coated on the outer surface of the reinforcement (1), and a polyamide active layer (3) formed on the outer surface of the polymeric resin thin film. The present invention has an advantage of an excellent strength and an increase in membrane area relative to an installation area.

Abstract: A modified polyamide membrane and method for making and using the same. The present invention includes many embodiments including methods comprising contacting a polyamide membrane with certain modifiers, including but not limited to certain oxazoline and/or thiazoline-based compounds, derivatives and polymers thereof. In one embodiment, the surface of a polyamide membrane is coated with a solution including a polyoxazoline and optionally a polyalkylene oxide material, followed by optional heating. Preferred embodiments may exhibit improved performance, e.g. increased rejection of certain species, (e.g. sodium chloride and/or boric oxides such as boric acid or various borate salts), reduced fouling, improved antimicrobial properties, and/or improved storage stability.

Abstract: A polymetaphenylene isophthalamide-based polymer porous film having a satisfactory porous structure that exhibits excellent gas permeability and heat resistance. It is produced by a process which comprises casting a dope of the polymetaphenylene isophthalamide-based polymer and coagulating it in a coagulating bath. The porous film may also contain inorganic whiskers, and a composite porous film may be formed in combination with a separate thermoplastic polymer film.

Abstract: A porous polymeric membrane formed from a blend of a polymeric membrane forming material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity modifying agent adapted to modify the surface active properties of the porous polymeric membrane. The reactivity modifying agent is preferably a linear polymeric anhydride, such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications include modification of the hydrophilicity/hydrophobicity balance of the membrane, or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide layer. Such modified membranes have use as reverse osmosis membranes.

Abstract: The present invention provides a positively charged microporous membrane having a protein binding capacity of about 25 mg/ml or greater comprising a hydrophilic porous substrate and a crosslinked coating that provides a fixed positive charge to the membrane. The present invention further provides a positively charged microporous membrane comprising a porous substrate and a crosslinked coating comprising pendant cationic groups. The membranes of the present invention find use in a variety of applications including ion-exchange chromatography, macromolecular transfer, as well as detection, filtration and purification of biomolecules such as proteins, nucleic acids, endotoxins, and the like.

Abstract: Membranes are used to separate fluids for the production of oxygen-enriched air, nitrogen-enriched-air, for the separation of carbon dioxide from hydrocarbons, and the separation of hydrogen from various petrochemical and oil refining streams. Membranes are discussed that provide a resistance to interaction with process components or contaminants, which can lead to plasticizing of the membrane, while providing the mechanical strength required to withstand high membrane differential pressures and high process temperatures. Membranes of blended polymers are used to improve the mechanical strength of the polymers used to make separation membranes. Specifically, polyimide polymers are combined with a blend polymer that is a polyamide and/or a polyamide-imde polymer. The resulting polymer mix is used to produce various forms of high strength, chemically resistant membranes, including hollow-fiber membranes that are suitable for high pressure, high temperature applications.

Abstract: Articles comprising a fibrous support of nanofibers and an interfacially polymerized polymer layer disposed on a surface of the fibrous support are useful, e.g., as fluid separation membranes.

Abstract: The present invention relates to a novel proton-conducting polymer membrane based on polyazoles which can, because of its excellent chemical and thermal properties, be used in a variety of ways and is particularly useful as polymer electrolyte membrane (PEM) to produce membrane electrode units for PEM fuel cells.

Abstract: The problem addressed by this invention is to provide an aromatic polyamide porous film excellent in the capability of being thinned and capable of easily exhibiting stable porosity properties even if it is used for a long period of time at high temperature. This invention can be achieved by an aromatic polyamide porous film that contains an aromatic polyamide as a main component and is such that when an atomic force microscope is used to measure a range of S ?m2 at least on one surface, the sectional area S(10) ?m2 obtained at a depth of 10 nm from the surface and the sectional area S(20) ?m2 obtained at a depth of 20 nm from the surface satisfy the following formulae simultaneously. 0.01?S(10)/S?0.

Abstract: A polyamide having an equilibrium water absorption of not more than 10% is used as a main material. As a polyamide having an equilibrium water absorption of not.more than 10%, for example, a polyamide comprising a dicarboxylic acid component comprising 60-100 mol % of terephthalic acid and a diamine component comprising 60-100 mol % of 1,9-nonanediamine and/or 2-methyl-1,8-octanediamine is used. As a result, a porous membrane showing extremely small dimensional change even after a hot water treatment, and particularly useful as a medical separation membrane permitting an AC sterilization treatment and the like is obtained.

Abstract: The present invention provides porous media or membranes having a surface coating that includes a first coating of a cross-linked terpolymer and a second coating comprising a copolymer or a terpolymer modified with a hydrophilic or hydrophobic functional group which has a superior combination of properties, including heat stable biomolecule resistant adsorptive properties, resistance to strong alkaline solutions, and low levels of extractable matter.

Abstract: A composite semipermeable membrane which satisfies the following relationship when seawater at 25° C. having a pH of 6.5, a boron concentration of 5 ppm and a TDS concentration of 3.5% by weight is permeated under an operation pressure of 5.5 MPa: Boron removal ratio (%)?95?4×membrane permeation flow rate (m3/m2·day).

Abstract: The invention pertains to a device for the condensation of water from an aqueous liquid by using a temperature gradient, which device includes: (a) a vapor chamber that can be brought in contact with a condensation compartment wherein at least part of the water vapor from the aqueous liquid condenses, and wherein inside of said vapor chamber is located (b) an evaporation compartment having a least a wall with an outer surface and which includes a closed, hollow and water permeable membrane wherein the vapor chamber has an outer surface that includes a substantially water-impermeable insulation skirt with an inner and an outer surface, such that there is a gap between the inner surface of the insulation skirt and the outer surface of the evaporation compartment, and wherein the vapor chamber has a lower surface of an active width (w) which is at least 10% of the effective diameter (d) of the evaporation compartment.

Abstract: A selective membrane having a high fouling resistance. In one embodiment, the selective membrane is a composite polyamide reverse osmosis membrane in which a hydrophilic coating is applied to the polyamide layer of the membrane, the hydrophilic coating being made by covalently bonding a hydrophilic compound to residual acid chlorides of the polyamide membrane, the hydrophilic compound including (i) at least one reactive group that is adapted to covalently bond directly to the polyamide membrane, the at least one reactive group being at least one of a primary amine and a secondary amine; and (ii) at least one non-terminal hydroxyl group.

Abstract: The present invention relates to a permeable membrane diaphragm of different layers for electrolytic cell, especially for chloro-alkali electrolytic cell. The diaphragm is asymmetric, which comprises at least two layers: a flow-controlling permeable layer comprising micro-porous fluoropolymer, especially PTFE, and a diffusion-restricting permeable layer comprising porous film, sheet or cloth made of anticorrosive materials, preferably polypropylene. The flow-controlling layer is mounted near the anode, and the diffusion-restricting layer is mounted near the cathode. The mean pore diameter of the diffusion-restricting layer is at least 5 times more than that of the flow-controlling layer and the thickness of the diffusion-restricting layer is at least 1 times more than that of the flow-controlling layer. The pore diameter of said flow-controlling layer ranges from 0.1–2.0 ?m, and its thickness is 0.03–0.2 mm. The pore diameter of said diffusion-restricting layer ranges from 5–50 ?m, and its thickness is 0.

Abstract: The present invention provides a positively charged microporous membrane having a protein binding capacity of about 25 mg/ml or greater comprising a hydrophilic porous substrate and a crosslinked coating that provides a fixed positive charge to the membrane. The present invention further provides a positively charged microporous membrane comprising a porous substrate and a crosslinked coating comprising pendant cationic groups. The membranes of the present invention find use in a variety of applications including ion-exchange chromatography, macromolecular transfer, as well as detection, filtration and purification of biomolecules such as proteins, nucleic acids, endotoxins, and the like.

Abstract: The invention relates to a method for producing a hydrolytically stable polyamide membrane having an open-pored, microporous and sponge-like support-layer structure, using a process involving thermally induced liquid-liquid phase separation. A solution of an aliphatic polyamide in a solvent system, comprising preferably a solvent and a non-solvent for the polyamide, is extruded to form a shaped object. After leaving the die, the shaped object is cooled by means of a cooling medium until phase separation occurs and the polymer-rich phase solidifies to form the membrane structure. The solution of the polyamide in the solvent system contains an antioxidant agent as a stabiliser for the polyamide which, together with the solvent system, is selected in a way that the antioxidant agent is essentially insoluble in the solvent system at the phase separation temperature.

Abstract: The present invention provides methods for determining a ratio of an amount of a glycated form of a protein to a total amount of the protein in a sample containing the glycated protein, the glycosylated protein, or the glycoprotein. The method incorporates lateral flow test strip or vertical flow test strip devices having negatively charged carboxyl or carboxylate groups and hydroxyboryl groups immobilized and interspersed on a solid support matrix. The solid support matrix may include derivatives of cellulose (e.g., carboxy cellulose) derivatized with carboxylic acid (e.g., carboxylate, carboxyl) groups and hydroxyboryl compounds including phenylboronic acid (e.g., phenylborate), aminophenylboronic acid, boric acid (e.g., borate), or other boronic acid (e.g., boronate) compounds. The present invention is usefi.il for monitoring glycation or glycosylation of hemoglobin or albumin for monitoring glycemic control (e.g., glycemia in diabetes).

Abstract: A polymeric composite may be used for forming fluid separation membranes. The membranes may be formed from polyimide, polyamide or poly (pyrrolone-imide) materials. Polyamides may be formed by the condensation of a tetraamine, a tetraacid, and a diamine. Polyimides and poly (pyrrolone-imides) may be formed by the cyclization of a polymer precursor. A polymeric composite may include a dithiolene or a mixture of dithiolenes. A polymer matrix incorporating dithiolenes may exhibit an olefin/paraffin solubility selectivity. A solubility selectivity may be between about 1.1 and about 2.0.

Abstract: A package assembly comprising a sealed water-impermeable bag enclosing: a spiral wound filtration element comprising a piperazine-based membrane, and an aqueous solution comprises a substantially non-oxidizable buffer having capacity to sequester at least 0.0025 moles per liter of hydrogen ions. The assembly preferably further includes a reducing agent. The assembly provides improved preservation for piperazine-based membranes and elements incorporating such membranes.

Abstract: Semi-permeable membranes are described that allow for the efficient processing of many liquid based feed solutions, particularly those that contain acids. The membranes of this invention are able to process such feeds with high permeate rates while maintaining excellent retention of dissolved metals, cations, and organic compounds, even in the presence of hot concentrated acids. The semi-permeable membranes of this invention are able to conduct such separations for a useful period of time due to their chemical stability towards acids and their ability to permeate acids.

Abstract: The present invention provides, in certain embodiments, a negatively charged microporous membrane comprising a porous substrate and a crosslinked coating having fixed negative charges. The crosslinked coating can be prepared, e.g., from a polymerized composition comprising an unsaturated monomer having an anionic group, an N-(hydroxymethyl)- and/or N-(alkoxymethyl)-acrylamide, a hydrophilic unsaturated monomer, and an initiator. The present invention further provides, in some embodiments, a negatively charged microporous membrane comprising a porous substrate and a crosslinked coating prepared from a polymerized composition comprising an unsaturated monomer having an anionic group, an N-(hydroxymethyl)- or N-(alkoxymethyl)-acrylamide, a polysaccharide, and an initiator. The membranes of the present invention are suitable for use in ion exchange chromatography, for example, in the separation and purification of positively charged species such as proteins.

Abstract: The present invention provides a positively charged microporous membrane having a protein binding capacity of about 25 mg/ml or greater comprising a hydrophilic porous substrate and a crosslinked coating that provides a fixed positive charge to the membrane. The present invention further provides a positively charged microporous membrane comprising a porous substrate and a crosslinked coating comprising pendant cationic groups. The membranes of the present invention find use in a variety of applications including ion-exchange chromatography, macromolecular transfer, as well as detection, filtration and purification of biomolecules such as proteins, nucleic acids, endotoxins, and the like.

Abstract: A composite semipermeable membrance of the present invention comprises a thin film and a porous support membrane supporting the thin film, wherein the thin film includes polyamide based resin having a constituent unit with amide bond between diamine residue and di or tri carboxylic acid residue, in which nitrogen atom of the amide bond has a substituent of aromatic ring. A production method of this invention includes a contacting step of contacting the above composite semipermeable membrane with solution including an oxidizer. In addition, a water treatment method of this invention comprises a step of separating a raw water by a composite semipermeable membrane to obtain permeation water in which salt and/or organic substance is removed sufficiently in practical use, characterized in that the composite semipermeable membrane of this invention is used and a fungicide is added into the raw water.

Abstract: The present invention provides porous media or membranes having a surface coating that includes a first coating of a cross-linked terpolymer and a second coating comprising a copolymer or a terpolymer modified with a hydrophilic or hydrophobic functional group which has a superior combination of properties, including heat stable biomolecule resistant adsorptive properties, resistance to strong alkaline solutions, and low levels of extractable matter.

Abstract: Segregating membrane supporting material is a three-dimensional assembly of fibers thermo-compressed into non-woven fabric, and the non-woven fabric fibers are joined together in sheet form. This segregating membrane supporting material is non-woven fabric, including at least 10 weight % polyacrylonitrile-based synthetic fibers, which is thermo-compressed to give an overall bulk density 40% to 75% of the density of the fibers which make up the non-woven fabric.

Abstract: A process for imparting hydrophilic properties to a polymeric membrane by exposing the membrane to an acrylate monomer containing hydrophilic segments, such as ethylene oxide, and a hydrophilic functional group, a diacrylate monomer containing hydrophilic functional groups, and an initiator for facilitating crosslinking and polymerization reactions.

Abstract: Novel low pressure reverse osmosis and nanofiltration membranes and a process for their preparation are disclosed. Polyamide reverse osmosis membranes are contacted with organic sulfonic acid solutions without the need for additional treatment by a rejection enhancing agent. These membranes provide sodium chloride rejections of greater than 20 percent and water fluxes greater than 15 gallons per square foot per day at a test pressure of 75 psi. Optimally treated membranes when tested similarly on 0.2 percent magnesium sulfate provide rejections greater than 95 percent with water fluxes greater than 15 gallons per square foot per day.

Abstract: A selective membrane having a high fouling resistance. In one embodiment, the selective membrane is a composite polyamide reverse osmosis membrane in which a hydrophilic coating has been applied to the polyamide layer of the membrane, the hydrophilic coating being made by (i) applying to the membrane a quantity of a polyfunctional epoxy compound, the polyfunctional epoxy compound comprising at least two epoxy groups, and (ii) then, cross-linking the polyfunctional epoxy compound in such a manner as to yield a water-insoluble polymer.

Abstract: A hollow fiber microfiltration (MF) membrane is provided. The casting solution used to make this membrane includes a fiber-forming polymer having a degree of polymerization greater than about 1000, a water-soluble polymer, an anhydride with about 2 to 12 carbon atoms, and a solvent. The membrane is formed by mixing and heating these components to form a viscous dope and then extruding the dope through an annular orifice to form a hollow fiber MF membrane. The hollow fiber membrane is then fed through a coagulation bath and two leaching baths. The membrane is especially useful for filtering liquids, such as wine and juice, so as to remove bacteria, gel, and solid particles from the liquids.

Abstract: The present invention relates to a silicone-coated organic solvent resistant polyamide composite nanofiltration membrane and a method for preparing the same. More particularly, the present invention relates to a nanofiltration composite membrane that is not only rejection rate superior but also organic solvent stable and flux excellent, prepared by coating with silicone during the process of interfacial polymerization of polyamide on the surface of porous support; and a method for producing it.

Abstract: A porous polymeric membrane formed from a blend of a polymeric membrane forming material, such as polyvinylidene fluoride or polysulfone and a polymeric reactivity modifying agent adapted to modify the surface active properties of the porous polymeric membrane. The reactivity modifying agent is preferably a linear polymeric anhydride, such as poly(alkyl vinyl ether/maleic anhydride). The surface activity modifications include modification of the hydrophilicity/hydrophobicity balance of the membrane, or hydrolysis followed by reaction with a polyamine to form a crosslinked polyamide layer. Such modified membranes have use as reverse osmosis membranes.

Abstract: A composite membrane and method for making the same, comprising a porous support and a polyamide surface. The subject membrane provides improved flux and/or rejection rates. The subject membrane is further capable of operating at lower operating pressures. The subject method includes reacting a polyfunctional amine with a polyfunctional acyl halide to form a polyamide. The method includes the step of contacting a complexing agent with the polyfunctional acyl halide prior substantial reaction between the polyfunctional acyl halide and a polyfunctional amine. The subject process is easily adapted to commercial scale manufacturing processes and is particularly suited for making nanofiltration and reverse osmosis composite membranes.

Abstract: A microporous membrane comprising a highly electropositive hydrophilic material capable of irreversibly binding one or more nucleic acids, the membrane being useful for isolating, amplifying and detecting nucleic acids is disclosed. Methods of making the membrane and using the membrane for amplifying nucleic acids are also disclosed.

Abstract: The present invention provides, in certain embodiments, a negatively charged microporous membrane comprising a porous substrate and a crosslinked coating having fixed negative charges. The crosslinked coating can be prepared, e.g., from a polymerized composition comprising an unsaturated monomer having an anionic group, an N-(hydroxymethyl)- and/or N-(alkoxymethyl)-acrylamide, a hydrophilic unsaturated monomer, and an initiator. The present invention further provides, in some embodiments, a negatively charged microporous membrane comprising a porous substrate and a crosslinked coating prepared from a polymerized composition comprising an unsaturated monomer having an anionic group, an N-(hydroxymethyl)- or N-(alkoxymethyl)-acrylamide, a polysaccharide, and an initiator. The membranes of the present invention are suitable for use in ion exchange chromatography, for example, in the separation and purification of positively charged species such as proteins.

Abstract: The present invention provides a positively charged microporous membrane having a protein binding capacity of about 25 mg/ml or greater comprising a hydrophilic porous substrate and a crosslinked coating that provides a fixed positive charge to the membrane. The present invention further provides a positively charged microporous membrane comprising a porous substrate and a crosslinked coating comprising pendant cationic groups. The membranes of the present invention find use in a variety of applications including ion-exchange chromatography, macromolecular transfer, as well as detection, filtration and purification of biomolecules such as proteins, nucleic acids, endotoxins, and the like.

Abstract: Sulfonamide polymer matrices and their various uses are disclosed. Among the uses is the configuration of the matrix with a porous support membrane to form a semipermeable membrane of the invention. The matrix of the invention is ultrathin, dense and substantially free of defects. The matrix configuration as the semipermeable membrane shows improved permeate flux and retention values.

Abstract: The present invention provides a composite reverse osmosis membrane as a polyamide membrane including a side chain amino group such as a residue of a polyvinyl alcohol-based amine compound represented by Formula 1. Such a membrane can remove organic impurities under a low pressure, providing an economical method for removal of impurities. An aqueous solution including a polyvinyl alcohol-based amine compound having a side chain amino group represented by Formula 1 is applied on a polysulfone-based ultrafiltration membrane as a microporous support. Next, trimesic acid chloride solution is applied causing interfacial polycondensation, which generates a reverse osmosis membrane. When this composite reverse osmosis membrane is evaluated by using a pH 6.5 aqueous solution including 500 mg/l of sodium chloride at an operation pressure of 5 kg/cm2 and at a temperature of 25° C., the permeable flux is at least 1.5 m3/m2·d, and the salt rejection is 80% or less.

Abstract: A composite semipermeable membrane which satisfies the following relationship when seawater at 25° C. having a pH of 6.5, a boron concentration of 5 ppm and a TDS concentration of 3.5% by weight is permeated under an operation pressure of 5.5 MPa: Boron removal ratio (%)≧95−4×membrane permeation flow rate (m3/m2·day).

Abstract: The present invention relates to nanofiltration and reverse osmosis membranes that may be used in a number of commercial applications in which a contaminant, such as salt, must be separated from a feed fluid, such as brackish water, to yield a purified product fluid, as well as a method for manufacturing such membranes. According to embodiments of the invention, an aqueous amine solution including an amine, an organic acid (e.g., propionic acid) and a non-amine base is applied to the surface of a porous substrate. A second solution containing an acyl halide and an organic solvent immiscible in water is then applied to the aqueous amine solution to cause interfacial polymerization to occur. The resulting membranes exhibit superior salt rejection and flux properties.

Abstract: A composite semipermeable membrane obtained by contacting, with an aqueous oxidizer solution, a composite semipermeable membrane comprising a thin film including polyamide based resin having a constitutional unit in which a diamine residue and di- or tri-carboxylic acid residue are amido-bonded, and the diamine residue is a residue of a secondary diamine whose hydrogen in an N position of an aromatic diamine is substituted by an alkyl group, and a porous support membrane for supporting the thin film has practical water flux, and excellent desalting faculty and excellent oxidizer resistance.

Abstract: In the treatment, a reverse osmosis membrane element having a polyamide skin layer is loaded in a pressure vessel in a membrane separator and contacted with a bromide-containing aqueous solution of free chlorine. The thus treated reverse osmosis membrane element retains for a long time its effect of reducing solute concentration in a solution treated with the reverse osmosis membrane and rejects efficiently non-electrolytic organic materials or substances such as boron that will not be dissociated in a neutral region. A reverse osmosis membrane module having the thus treated reverse osmosis membrane element is provided as well.

Abstract: A water treatment apparatus according to the present invention includes a plurality of composite reverse osmosis membrane modules arranged in multi-stages, each of the modules including a porous support and a polyamide skin layer formed on the porous support. In this apparatus, the module at the final stage is supplied with some of permeated water obtained from at least one module preceding the module at the final-stage, and a rest of the permeated water is discharged from or recovered in the apparatus along with permeated water obtained from the final-stage module.

Abstract: The present invention provides, in certain embodiments, a negatively charged microporous membrane comprising a porous substrate and a crosslinked coating having fixed negative charges. The crosslinked coating can be prepared, e.g., from a polymerized composition comprising an unsaturated monomer having an anionic group, an N-(hydroxymethyl)- and/or N-(alkoxymethyl)-acrylamide, a hydrophilic unsaturated monomer, and an initiator. The present invention further provides, in some embodiments, a negatively charged microporous membrane comprising a porous substrate and a crosslinked coating prepared from a polymerized composition comprising an unsaturated monomer having an anionic group, an N-(hydroxymethyl)- or N-(alkoxymethyl)-acrylamide, a polysaccharide, and an initiator. The membranes of the present invention are suitable for use in ion exchange chromatography, for example, in the separation and purification of positively charged species such as proteins.

Abstract: The present invention provides a positively charged microporous membrane having a protein binding capacity about 25 mg/ml or greater comprising a hydrophilic porous substrate and a crosslinked coating that provides a fixed positive charge to the membrane. The present invention further provides a positively charged microporous membrane comprising a porous substrate and a crosslinked coating comprising pendant cationic groups. The membranes of the present invention find use in a variety of applications including ion-exchange chromatography, macromolecular transfer, as well as detection, filtration and purification of biomolecules such as proteins, nucleic acids, endotoxins, and the like.

Abstract: The present invention relates to a composite semipermeable membrane, which is useful as a reverse osmosis membrane or a nano-filtration membrane and comprises a polysulfone porous support membrane and a polyamide ultrathin layer formed on one of the surfaces of the porous support membrane, the composite membrane having the characteristic that in the infrared absorption spectrum obtained from the surface of a polyamide ultrathin layer of the composite semipermeable membrane, the ratio T (=Aa/As) of absorption intensity Aa at the absorption peak revealing C═O of polyamide in the region of 1600-1700 cm−1 to absorption intensity As at the absorption peak revealing polysulfone at a wavenumber around 1586 cm−1 is at least 0.05 and not higher than 3.

Abstract: An at least two layer, unsupported, continuous microporous membrane is disclosed. The at least two layer, unsupported, continuous microporous membrane may include at least two different membrane pore size layers or the pore sizes may have about the same pore size. Apparatus and processes for fabricating at least a two layer unsupported, continuous, microporous membrane are also disclosed.

Abstract: An ammonium selective ionophore for use in ion selective electrodes.

Abstract: A composite reverse osmosis membrane is described, which includes a polyamide skin layer on a porous support, with a contact angle between the polyamide skin layer surface and water of 45° or less. The composite reverse osmosis membrane has a high salt rejection and also a high water permeability. This composite reverse osmosis membrane is produced by forming a polyamide skin layer on a porous support having the steps of: forming a layer on the porous support by coating a solution A including one or more compounds having at least two reactive amino groups; contacting the layer with a solution B comprising one or more polyfunctional acid halide compounds; and subsequently, contacting the layer with a solution C comprising the polyfunctional acid halide compound of a higher concentration than the solution C. The concentration of the polyfunctional acid halide compound in the solution C is preferably at least 1.2 times of the solution B.

Abstract: A composite membrane and method for making the same, comprising a porous support and a crosslinked polyamide surface. The subject membrane provides improved flux and/or rejection rates. The subject membrane is further capable of operating at lower operating pressures. The subject method includes reacting a polyfunctional amine with a polyfunctional acyl halide to form a polyamide. The method includes the step of contacting a phosphorous containing compound with the polyfunctional acyl halide prior to and/or during the reaction between the polyfunctional acyl halide and a polyfunctional amine. The subject process is easily adapted to commercial scale manufacturing processes and is particularly suited for making nanofiltration and reverse osmosis composite membranes.