The invention provides mixed matrix membranes (MMMs) for olefin/paraffin separation and methodes of making and using the same. The MMMs comprise a continuous polymer matrix with metal doped zeolite nano-particles. A separation technology based upon the composite membranes is effective for propylene and other olefin separation from olefin/paraffin mixtures, and the separation is more energy-efficient than the conventional cryogenic technique.

The invention provides mixed matrix membranes (MMMs) for olefin/paraffin separation and methodes of making and using the same. The MMMs comprise a continuous polymer matrix with metal doped zeolite nano-particles. A separation technology based upon the composite membranes is effective for propylene and other olefin separation from olefin/paraffin mixtures, and the separation is more energy-efficient than the conventional cryogenic technique.

System, devices, and method for the production of thin film composite hollow fiber membranes on a hollow fiber support structure. The system includes a comb and roller device, or comb and dual roller device, which can be used to define a submerged travel path in a first solution bath for a hollow fiber. The combs and rollers control the amount of time the hollow fiber spends in the first solution. The first solution contains a first monomer, and the hollow fiber is impregnated with the first monomer. The amount of impregnation depends on the time spent in the first solution. Subsequent immersion in a second solution containing a second monomer results in the formation of a thin film composite hollow fiber membrane.

A method for making metal organic frameworks (MOFs) includes the step of dissolving metal salts in deionized water to form first solution, followed by adding a cyclic propyl phosphonic anhydride reagent to the first solution to form a second solution. The second solution is heated to form a reaction mixture containing MOF crystals, and is then cooled. The MOF crystals are filtered therefrom, washed and dried. To make metal organic framework-based thin film nanocomposite membranes, the MOF crystals are mixed with an m-phenylene diamine aqueous solution to form a mixture, which is then poured on a top surface of an ultrafiltration membrane substrate to form a first intermediate membrane structure. The first intermediate membrane structure is dried, and trimesolyl chloride in n-hexane solution is poured thereon to form a second intermediate membrane structure, which is cured to form an MOF-based thin film nanocomposite membrane, which is then rinsed and dried.

The purpose of the present invention is to provide: a thin composite semipermeable membrane having a practical salt rejection and permeation flux; a method for producing said membrane; and a spiral wound separation membrane element that has a practical salt rejection and provides excellent water treatment efficiency. The method for producing the composite semipermeable membrane includes a step in while, while feeding out a porous support having a porous polymer layer on one surface of a nonwoven fabric layer from a supply roll, an amine solution containing a multifunctional amine component is brought into contact with the porous support, and an organic solution containing a multifunctional acid halide component is brought into contact with the amine solution on the porous support to cause interfacial polymerization, thus forming a skin layer containing a polyamide resin on the surface of the porous support.

The purpose of the present invention is to provide: a thin composite semipermeable membrane having a practical salt rejection and permeation flux; a method for producing said membrane; and a spiral wound separation membrane element that has a practical salt rejection and provides excellent water treatment efficiency. The method for producing the composite semipermeable membrane includes a step in while, while feeding out a porous support having a porous polymer layer on one surface of a nonwoven fabric layer from a supply roll, an amine solution containing a multifunctional amine component is brought into contact with the porous support, and an organic solution containing a multifunctional acid halide component is brought into contact with the amine solution on the porous support to cause interfacial polymerization, thus forming a skin layer containing a polyamide resin on the surface of the porous support.

Provided are a composite semipermeable membrane that will maintain a sufficient level of rejection performance even when produced using different thicknesses of a porous support or different production conditions, a separation membrane element having such a composite semipermeable membrane, and a method for producing such a composite semipermeable membrane. The composite semipermeable membrane includes a porous support including a nonwoven fabric layer and a polymer porous layer on one surface of the nonwoven fabric layer; and a separation function layer on the surface of the porous support, wherein the porous support has a defect frequency F1 of 50 or less per 480 m.sup.2 with respect to defects having a width of 0.3 mm or more perpendicular to the direction of the polymer porous layer production line, when the relationship between the size and frequency of defects in the porous support is measured with transmitted light.

Provided are a cleaning agent and a cleaning liquid that prevent a reduction in the rejection rate of an RO membrane which may occur when the RO membrane is cleaned and a method for cleaning an RO membrane with the cleaning liquid. The agent for cleaning an RO membrane includes a urea derivative. The urea derivative preferably includes urea (H.sub.2N—CO—NH.sub.2) and/or biuret (H.sub.2N—CO—NH—CO—NH.sub.2). The cleaning liquid is an aqueous solution produced by diluting the cleaning agent. The method for cleaning an RO membrane uses the cleaning liquid. Urea and biuret have a structure analogous to amide bonds included in aromatic polyamide RO membranes, and have a strong affinity for amide bond portions. Urea and biuret adsorb onto the amide bond portions, and prevent the amide bonds from being broken by the cleaning liquid.

Provided are a cleaning agent and a cleaning liquid that prevent a reduction in the rejection rate of an RO membrane which may occur when the RO membrane is cleaned and a method for cleaning an RO membrane with the cleaning liquid. The agent for cleaning an RO membrane includes a urea derivative. The urea derivative preferably includes urea (H.sub.2N—CO—NH.sub.2) and/or biuret (H.sub.2N—CO—NH—CO—NH.sub.2). The cleaning liquid is an aqueous solution produced by diluting the cleaning agent. The method for cleaning an RO membrane uses the cleaning liquid. Urea and biuret have a structure analogous to amide bonds included in aromatic polyamide RO membranes, and have a strong affinity for amide bond portions. Urea and biuret adsorb onto the amide bond portions, and prevent the amide bonds from being broken by the cleaning liquid.

Poly(amino acids) having hydrophilic side groups may be grafted onto active surfaces of polyamide composite membranes so as to confer fouling resistance. Polylysine, polyhistidine, polyarginine and their blends with polyglutamic acid may be grafted to membrane surfaces via amide linkages or via peroxide-induces bonding, modifying membrane surfaces behavior towards foulants.