Nitto-denko Corporation

Masashi Echizen

Tomotsugu Miyabe

Taisuke Yamaguchi

Kazusa Matsui

Kouji Maruyama

Naoki Kurata

Takuji Shintani

Mieko Nishi

Atsuhito Komoto

Atsuko Mizuike

Yuha Okazaki

Kazusa Hitouji

Yasuyuki Sakakibara

Nagahisa Sato

A sulfate ion removal systemincludes: a flow passage; and a nanofiltration membranethat is provided in the flow passage, has a cationic coatingconstituting 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, the water to be treated is, for example, injection water to be injected into an oil field.

Sulfate ion removal system and method for removing sulfate ion

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 99.9:0.1 to 98:2 (segment (A):segment (B)). 

Composite semipermeable membrane and spiral wound separation membrane element

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.

Spiral membrane element

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 &#x3bc;m to 100 &#x3bc;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.

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.

Composite semi-permeable membrane

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 () 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 () which includes a separation membrane () of which the membrane face () can be monitored and guides the supply liquid so as to separate the membrane, and a concentrating-side membrane separation means () which includes a separation membrane () of which the membrane face () can be monitored and guides the concentrated liquid so as to separate the membrane separation thereof.

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Osaka, Japan

Masashi Echizen