Abstract: A composite semipermeable membrane 12 of the present invention includes a porous support membrane 12a and a skin layer 12b supported by the porous support membrane 12a. The membrane surface of the composite semipermeable membrane 12 has an elastic modulus of 250 MPa or more and 500 MPa or less as calculated by force curve measurement using AFM in water. A spiral membrane element 20 of the present invention includes the composite semipermeable membrane 12 of the present invention. A water treatment system 100 of the present invention includes the spiral membrane element 20 of the present invention.

Abstract: A sulfate ion removal system 100 includes: a flow passage 50; and a nanofiltration membrane 62 that is provided in the flow passage 50, has a cationic coating 40 constituting a surface of the membrane, and removes a sulfate ion contained in water to be treated by filtering the water to be treated. Treated water obtained by filtering, with the nanofiltration membrane 62, the water to be treated is, for example, injection water to be injected into an oil field.

Abstract: The purpose of the present invention is to provide: a composite semipermeable membrane which has three excellent properties, namely, excellent ionic substance rejecting property, excellent nonionic substance rejecting property and excellent water permeability in a practically balanced manner, and a spiral wound separation membrane element which comprises this composite semipermeable membrane. A composite semipermeable membrane according to the present invention is obtained by forming a skin layer that contains a polyamide-based resin on a surface of a porous support, and is configured such that: the polyamide-based resin is obtained by polymerizing a polyfunctional acid halide component and a polyfunctional amine component; the polyfunctional amine component contains m-phenylenediamine and at least one diamine compound represented by general formula (1); and a ratio (mol %) of a segment (A) derived from m-phenylenediamine and a segment (B) derived from the diamine compound in the polyamide-based resin is 99.

Abstract: A sulfate ion removal system 100 of the present invention includes: a flow passage 50; and a nanofiltration membrane 62 that is provided in the flow passage 50, has a cationic coating 40 constituting a surface of the membrane, and removes a sulfate ion contained in water to be treated by filtering the water to be treated. Treated water obtained by filtering, with the nanofiltration membrane 62, the water to be treated is, for example, injection water to be injected into an oil field.

Abstract: The present invention relates to a composite semipermeable membrane including: a porous layer; a membrane separation layer provided on the porous layer; and the porous layer contains a crystalline polymer, wherein a crystallinity of the crystalline polymer is 30% or more and 50% or less.

Abstract: The present invention relates to a composite semipermeable membrane including: a porous layer; a membrane separation layer provided on the porous layer; and the porous layer contains a polymer, the polymer containing one of either a fluoropolymer or an imide group-containing polymer, wherein a compression ratio of a portion including the porous layer and the membrane separation layer when subjected to a pressure of 5.5 MPa is 60% or less.

Abstract: The object of the present invention is to provide a spiral membrane element that can make a composite semipermeable membrane high in effective membrane area, and that can restrain the composite semipermeable membrane from being lowered in rejection ratio by a deformation of this membrane while ensuring the flow rate of a permeation liquid flowing in a permeation-side flow-channel sufficiently. The spiral membrane element comprises a layered body which comprises a composite semipermeable membrane, a supply-side flow-channel member, and a permeation-side flow-channel member; and the permeation-side flow-channel member comprises a tricot knitted fabric having a plurality of ribs each formed by repeating loops in a linear form in a longitudinal direction, and a plurality of grooves present between the ribs; has a membrane support index of 60 to 135, the membrane support index being calculated in accordance with the specified numerical relationship.

Abstract: The present invention provides a spiral membrane element in which the effective membrane area of a composite semi-permeable membrane can be increased and any decrease in rejection rate is less likely to occur. The spiral membrane element includes: a laminate including a permeation-side flow path material, a supply-side flow path material, and a composite semi-permeable membrane having a separation function layer on a surface of a porous support; a perforated central tube around which the laminate is wound; and a sealing member for preventing mixing between the supply-side flow path and a permeation-side flow path, the spiral membrane element being characterized in that the thickness of the porous support of the composite semi-permeable membrane is 80 ?m to 100 ?m, the permeation-side flow path material is formed from a tricot knit fabric, and the width of a groove that continues in a straight line is 0.05 mm to 0.40 mm.

Abstract: The objective of the present invention is to provide a composite semi-permeable membrane having high processing efficiency even when processing of wastewater having a suspended matter content high enough to tend to result in clogging, said processing efficiency being unlikely to decline even under elevated-pressure operation accompanying continuous use at high pressure. The present invention pertains to a composite semi-permeable membrane having a polymer porous layer on one surface of a nonwoven cloth layer, and a polyamide separation function layer on the polymer porous layer, wherein the ratio of the thickness of the polymer porous layer to the thickness of the nonwoven cloth layer is 0.22 to 0.45.

Abstract: The purpose of the present invention is to provide: a composite semipermeable membrane which has three excellent properties, namely, excellent ionic substance rejecting property, excellent nonionic substance rejecting property and excellent water permeability in a practically balanced manner, and a spiral wound separation membrane element which comprises this composite semipermeable membrane. A composite semipermeable membrane according to the present invention is obtained by forming a skin layer that contains a polyamide-based resin on a surface of a porous support, and is configured such that: the polyamide-based resin is obtained by polymerizing a polyfunctional acid halide component and a polyfunctional amine component; the polyfunctional amine component contains m-phenylenediamine and at least one diamine compound represented by general formula (1); and a ratio (mol %) of a segment (A) derived from m-phenylenediamine and a segment (B) derived from the diamine compound in the polyamide-based resin is 99.

Abstract: The object of the present invention is to provide a spiral membrane element that can make a composite semipermeable membrane high in effective membrane area, and that can restrain the composite semipermeable membrane from being lowered in rejection ratio by a deformation of this membrane while ensuring the flow rate of a permeation liquid flowing in a permeation-side flow-channel sufficiently. The spiral membrane element comprises a layered body which comprises a composite semipermeable membrane, a supply-side flow-channel member, and a permeation-side flow-channel member; and the permeation-side flow-channel member comprises a tricot knitted fabric having a plurality of ribs each formed by repeating loops in a linear form in a longitudinal direction, and a plurality of grooves present between the ribs; has a membrane support index of 60 to 135, the membrane support index being calculated in accordance with the specified numerical relationship.

Abstract: The present invention provides a spiral membrane element in which the effective membrane area of a composite semi-permeable membrane can be increased and any decrease in rejection rate is less likely to occur. The spiral membrane element includes: a laminate including a permeation-side flow path material, a supply-side flow path material, and a composite semi-permeable membrane having a separation function layer on a surface of a porous support; a perforated central tube around which the laminate is wound; and a sealing member for preventing mixing between the supply-side flow path and a permeation-side flow path, the spiral membrane element being characterized in that the thickness of the porous support of the composite semi-permeable membrane is 80 ?m to 100 ?m, the permeation-side flow path material is formed from a tricot knit fabric, and the width of a groove that continues in a straight line is 0.05 mm to 0.40 mm.

Abstract: 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.

Abstract: 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 m2 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.

Abstract: The objective of the present invention is to provide a composite semi-permeable membrane having high processing efficiency even when processing of wastewater having a suspended matter content high enough to tend to result in clogging, said processing efficiency being unlikely to decline even under elevated-pressure operation accompanying continuous use at high pressure. The present invention pertains to a composite semi-permeable membrane having a polymer porous layer on one surface of a nonwoven cloth layer, and a polyamide separation function layer on the polymer porous layer, wherein the ratio of the thickness of the polymer porous layer to the thickness of the nonwoven cloth layer is 0.22 to 0.45.

Abstract: A method of membrane separation and membrane separation apparatus, with which not only a supply liquid can be evaluated but also the problems, such as scale, occurring on reverse osmosis membrane can be monitored in a highly straightforward fashion. There is provided a membrane separation apparatus equipped with reverse osmosis membrane module (3) so as to be adapted for feeding of a supply liquid and obtaining of a permeated liquid and a concentrated liquid, characterized by comprising a feeding-side membrane separation means (10) which includes a separation membrane (11) of which the membrane face (11a) can be monitored and guides the supply liquid so as to separate the membrane, and a concentrating-side membrane separation means (20) which includes a separation membrane (21) of which the membrane face (21a) can be monitored and guides the concentrated liquid so as to separate the membrane separation thereof.

Abstract: A method of membrane separation and membrane separation apparatus, with which not only a supply liquid can be evaluated but also the problems, such as scale, occurring on reverse osmosis membrane can be monitored in a highly straightforward fashion. There is provided a membrane separation apparatus equipped with reverse osmosis membrane module (3) so as to be adapted for feeding of a supply liquid and obtaining of a permeated liquid and a concentrated liquid, characterized by comprising a feeding-side membrane separation means (10) which includes a separation membrane (11) of which the membrane face (11a) can be monitored and guides the supply liquid so as to separate the membrane, and a concentrating-side membrane separation means (20) which includes a separation membrane (21) of which the membrane face (21a) can be monitored and guides the concentrated liquid so as to separate the membrane separation thereof.