Nitto-denko Corporation

Katsumi Ishii

Masaaki Ando

Satoru Ishihara

Yasuhiro Uda

Shinichi Chikura

Hiroki Fujioka

Yoshihide Kawaguchi

Noriaki Harada

Masashi Beppu

Atsushi Hiro

Osamu Hayashi

Atsuko Mizuike

Hideki Matsuda

Masahiko Hirose

Hisao Hachisuka

Takuji Shintani

Yuuji Nishida

Hiroki Itoh

It is an object of the present invention to provide a composite semi-permeable membrane exhibiting excellent chemical resistance and having practical water permeability and salt-blocking property, and a method for producing the same. The present invention relates to a composite semi-permeable membrane, including a porous support and a skin layer formed on a surface of the porous support, wherein the porous support contains a thermosetting resin porous sheet having a three-dimensional network structure and pores communicating with each other and wherein the thermosetting resin porous sheet has an average pore diameter of 0.01 to 0.4 &#x3bc;m.

Composite semi-permeable membrane and method for producing same

Disclosed is a method for easily producing a long porous thermosetting resin sheet which has no resin coating film on the surface. Also disclosed are a porous thermosetting resin sheet produced by the method, and a composite semipermeable membrane having excellent chemical resistance and practical water permeability and salt-blocking property. The porous thermosetting resin sheet can be produced by forming a cylindrical or columnar resin block which is composed of a cured product of a thermosetting resin composition containing a thermosetting resin, a curing agent and a porogen; then forming a long thermosetting resin sheet by cutting the surface of the resin block at a certain thickness; and then removing the porogen from the thermosetting resin sheet.

Method for producing porous thermosetting resin sheet, porous thermosetting resin sheet and composite semipermeable membrane using same

An object of the present invention is to provide a spiral membrane element that can form a uniform fiber reinforcement layer on an outer circumferential surface by a simple process without a great change in the materials, as well as a process for producing the same. The spiral membrane element of the present invention is a spiral membrane element which is provided with a cylindrical roll R in which a separation membrane, a feed-side flow passageway member, and a permeate-side flow passageway memberare spirally wound in a laminate state around a perforated center tubeand in which a sealing part for preventing mixing of feed-side fluid and permeate-side fluid is disposed, wherein at least one sheet of the permeate-side flow passageway memberhas a fiber clothextended or connected to the outer circumferential side, and the fiber clothis wound around an outer circumference of said cylindrical roll R, impregnated with a resin and hardened to thereby form a fiber reinforcement layer.

Spiral membrane element and process for producing the same

A membrane element sealing material holding member comprising a central opening for insertion of a center tube of spiral membrane element, peripheral orifice for flowing of a raw liquid into a membrane end portion of membrane element and outer circumferential part for holding of circular sealing material, wherein the central opening has inner circumferential surface of cylindrical form with a diameter larger than the outer diameter of the inserted center tube, and wherein at three or more positions on the inner circumferential surface, there is provided projection that has sloping face on its side of center tube insertion and is deformable at the time of insertion of center tube with an outer diameter larger than that of incircle.

Membrane element sealing material holding member and membrane element

A spiral wound membrane element allowing back wash reverse filtration at 0.05 MPa to 0.3 MPa is employed for a spiral wound membrane module. Air injection of injecting air of not more than 0.3 MPa into a permeate outlet of the spiral wound membrane module from a pressurized air feeder through a pipe, back wash reverse filtration with permeate and flushing with raw water are performed as recovery of a filtration velocity. Another spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. Raw water into which bubbles are diffused by an air diffuser is fed to the spiral wound membrane element stored in a pressure vessel. Part of the raw water is axially fed through the spiral wound membrane element, discharged from a raw water outlet of the pressure vessel and thereafter returned to a raw water tank through a pipe.

Running method and treatment system for spiral wound membrane element and spiral wound membrane module

A spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. The flow rate of permeate in filtration of the spiral wound membrane element is preferably set to 0.5 to 2.0 m/m/day, and the filtration time is preferably set to 10 to 300 minutes. The flow rate of wash water in washing is preferably set to 1.0 to 4.0 m/m/day, and the washing time is preferably set to 10 to 300 seconds. In such ranges, the ratio of the permeate volume in filtration to the permeate volume in back wash reverse filtration is set to be not more than 600.

Running method and washing method for spiral wound membrane element and spiral wound membrane module

A spiral wound membrane module comprises a spiral wound membrane element including a separation membrane having high back pressure strength. In filtration running, raw water introduced from a raw water inlet of a pressure vessel is subjected to dead end filtration, and permeate is taken out from a permeate outlet. In washing, wash water containing a chemical having a contaminant separating function is introduced from an end of a water collection pipe through the permeate outlet for performing back wash reverse filtration with a back pressure of 0.05 to 0.3 MPa. The filtration running is temporarily stopped for maintaining the pressure vessel in a state sealed with the raw water and the permeate for a prescribed time. Thus, contaminants adhering to the membrane surface of the spiral wound membrane element are separated. A treatment system is formed by connecting units comprising spiral wound membrane modules in parallel with each other. In the treatment system, one of the units is subjected to filtration running when another one of the units is washed. In washing, back wash reverse filtration and chemical soaking are performed.

Spiral wound membrane element, spiral wound membrane module and treatment system employing the same as well as running method and washing method therefor

A spiral wound type separation membrane element includes a spiral wound type membrane component formed by superposing separation membranes of membrane materials supported on nonwoven fabric members on both surfaces of a permeated liquid passage forming member and bonding three sides with an adhesive thereby defining an envelope-like membrane, mounting an opening of the envelope-like membrane on a water collection pipe and bonding the same with an adhesive and spirally winding the envelope-like membrane around the outer peripheral surface of the water collection pipe along with a raw liquid passage forming member. The outer peripheral surface of the envelope-like membrane forming the spiral wound type membrane component is covered with a sheath member, and anti-telescopic members are mounted on both end surfaces of the envelope-like membrane respectively. Each of the aforementioned components forming the spiral wound type separation membrane element is made of heat-resistant alkali-resistant plastic.

Spiral wound type separation membrane element

Disclosed are a composite semipermeable membrane which is excellent in the chlorine resistance and also gives a high desalting faculty and a large water flux, in particular, under a low operation pressure and a production method thereof. The composite semipermeable membrane comprises a porous base material having formed thereon a semipermeable thin film formed by crosslinking polymerization of 2,6-diaminotoluene monomer or a mixture of 2,6-diaminotoluene monomer and other amino compound monomer with a polyfunctional crosslinking agent having at least two functional groups capable of reacting with the amino group(s) of the monomer(s) in one molecule in the presence of an amine salt.

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Ibaraki, Japan

Katsumi Ishii