Abstract: According to the present invention, it is possible to obtain a separation membrane element which has an element configuration having high fresh water production performance and high removal performance, has an improved membrane surface linear velocity whereby fouling due to hardly-soluble salts (scales) or organic matters is less likely to occur on the membrane surface particularly in high recovery ratio operation, and is excellent in fresh water production performance and removal performance over a long period of time.

Abstract: This composite semipermeable membrane is provided with: a porous supporting membrane that comprises a base and a porous supporting layer; and a separating function layer that is provided on the porous supporting layer. With respect to this composite semipermeable membrane, the standard deviation of pore radius of the separating function layer as determined by positron annihilation lifetime measurement is 0.025 nm or less.

Abstract: The present invention pertains to a semipermeable composite membrane having a support film and a separation function layer, wherein, (A) in a semipermeable composite membrane equilibrated under specific conditions, the half value width H of an absorption peak between 3900 cm?1 and 2900 cm?1 in a difference spectrum Sd obtained by subtracting IR spectrum S2 from IR spectrum S1 is 355-373, and (B) in the IR spectrum S1, the value F obtained by dividing the area of the absorption intensity between 3900 cm?1 and 2900 cm?1 by the absorbance at the peak top between 1690 cm?1 and 1630 cm?1 is at least 850.

Abstract: According to the present invention, it is possible to obtain a separation membrane element which has an element configuration having high fresh water production performance and high removal performance, has an improved membrane surface linear velocity whereby fouling due to hardly-soluble salts (scales) or organic matters is less likely to occur on the membrane surface particularly in high recovery ratio operation, and is excellent in fresh water production performance and removal performance over a long period of time.

Abstract: This composite semipermeable membrane is provided with: a porous supporting membrane that comprises a base and a porous supporting layer; and a separating function layer that is provided on the porous supporting layer. With respect to this composite semipermeable membrane, the standard deviation of pore radius of the separating function layer as determined by positron annihilation lifetime measurement is 0.025 nm or less.

Abstract: Disclosed herein are a composite semipermerable membrane and a method for producing the same. The composite semipermeable membrane comprises a microporous support membrane and a separation functional layer provided on the microporous support membrane, wherein the separation functional layer contains a condensation product produced by condensation of at least one selected from the group consisting of ions of trialkoxysilanes each having an imidazolium group and a conjugated base of a polymer having at least one acidic group. The composite semipermeable membrane achieves excellent selective separation of divalent ions over monovalent ions, and is suitable for use in various water treatment fields such as seawater desalination and drinking water production.

Abstract: Disclosed is a composite semipermeable membrane, which comprises a separation functional layer on a microporous support, and in which the separation functional layer is made of a condensation product of a polymer that has acidic groups and a trialkoxysilane groups having an imidazolium structure in side chains. The composite semipermeable membrane has excellent selective separation performance for divalent ions over monovalent ions, while exhibiting excellent long-term durability. Also disclosed is a method for producing the composite semipermeable membrane. The composite semipermeable membrane is suitable for uses in various water treatment fields such as the desalination of seawater and the production of drinking water. In addition, the composite semipermeable membrane does not deteriorate as much as conventional composite semipermeable membrane even in cases where the membrane is sterilized by having chlorine-containing raw water permeate therethrough continuously or intermittently.

Abstract: Provided is a composite semipermeable membrane comprising a microporous support membrane and a separation functional layer formed thereon, wherein the separation functional layer is formed from Compound (A) in which a reactive group(s) having an ethylenically unsaturated group and a hydrolyzable group(s) are bonded directly to a silicon atom, Compound (B) having an ethylenically unsaturated group, the Compound (B) being different from said Compound (A), and Compound (C) having an ethylenically unsaturated group, the Compound (C) being different from said Compound (A) and (B), by condensation of hydrolyzable groups that the Compound (A) has and polymerization of ethylenically unsaturated groups that the Compound (A), the Compound (B), and the Compound (C) have, and the Compound (A), the Compound (B), and the Compound (C) satisfy the relationship of the following equation (I): |QA?QC|+|QB?QC|=|QA?QB|??(I) (QX represents an Alfrey-Price Q value of Compound X).

Abstract: Disclosed is a composite semipermeable membrane, which comprises a separation functional layer on a microporous support, and in which the separation functional layer is made of a condensation product of a polymer that has acidic groups and a trialkoxysilane groups having an imidazolium structure in side chains. The composite semipermeable membrane has excellent selective separation performance for divalent ions over monovalent ions, while exhibiting excellent long-term durability. Also disclosed is a method for producing the composite semipermeable membrane. The composite semipermeable membrane is suitable for uses in various water treatment fields such as the desalination of seawater and the production of drinking water. In addition, the composite semipermeable membrane does not deteriorate as much as conventional composite semipermeable membrane even in cases where the membrane is sterilized by having chlorine-containing raw water permeate therethrough continuously or intermittently.

Abstract: Disclosed herein are a composite semipermerable membrane and a method for producing the same. The composite semipermeable membrane comprises a microporous support membrane and a separation functional layer provided on the microporous support membrane, wherein the separation functional layer contains a condensation product produced by condensation of at least one selected from the group consisting of ions of trialkoxysilanes each having an imidazolium group and a conjugated base of a polymer having at least one acidic group. The composite semipermeable membrane achieves excellent selective separation of divalent ions over monovalent ions, and is suitable for use in various water treatment fields such as seawater desalination and drinking water production.