Provided is a post-formation process for preparation of a highly permeable thin film composite membranes for reverse osmosis, particularly for use with brackish water at low energy conditions. The process includes contacting a polyamide discrimination layer of a TFC membrane with a solution containing an oxidizing agent to form a treated membrane, followed by contacting the treated membrane with a solution containing a reducing agent. The resulting membrane exhibits enhanced water flux while maintaining salt rejection. Also provided are reverse osmosis membranes prepared in accord with the method, and modules containing the highly permeable thin film composite membranes, and methods of purifying water using the membranes or modules.

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.

The present invention is directed to asymmetric membranes and methods for making such membranes, wherein the membranes have a void volume and nanoparticles located in the void volume. The membranes have a variety of applications, including blood purification, water purification, water decontamination and bioprocessing.

Provided are a forward osmosis membrane, a forward osmosis membrane module, and a manufacturing method thereof, wherein a forward osmosis membrane, which achieves an extremely favorable reduction in the reverse diffusion of salt compared to the prior art and has a predetermined water permeability, is developed thereby bringing about: practicality in that a liquid-like raw material solution used in actual concentration operations can be concentrated with suppressed diffusion of an induction solution even when used multiple times; and durability in that the performance of the membrane can be maintained within a predetermined range even when a raw material solution having an osmotic pressure is concentrated multiple times. According to an aspect, provided is a forward osmosis membrane having a polymeric separation active layer disposed on the surface of a microporous support membrane, wherein when purified water is placed as a raw material solution on the separation active layer side and 3.5 mass % of a sodium chloride aqueous solution is placed as an induction solution on the support membrane side, with the forward osmosis membrane therebetween, the amount R1 of reverse diffusion of salt into the raw material solution is 0.65 g/(m.sup.2×hr) or less, and the amount F1 of water permeation into the induction solution is at least 3.5 kg/(m.sup.2×hr).

Provided are a forward osmosis membrane, a forward osmosis membrane module, and a manufacturing method thereof, wherein a forward osmosis membrane, which achieves an extremely favorable reduction in the reverse diffusion of salt compared to the prior art and has a predetermined water permeability, is developed thereby bringing about: practicality in that a liquid-like raw material solution used in actual concentration operations can be concentrated with suppressed diffusion of an induction solution even when used multiple times; and durability in that the performance of the membrane can be maintained within a predetermined range even when a raw material solution having an osmotic pressure is concentrated multiple times. According to an aspect, provided is a forward osmosis membrane having a polymeric separation active layer disposed on the surface of a microporous support membrane, wherein when purified water is placed as a raw material solution on the separation active layer side and 3.5 mass % of a sodium chloride aqueous solution is placed as an induction solution on the support membrane side, with the forward osmosis membrane therebetween, the amount R1 of reverse diffusion of salt into the raw material solution is 0.65 g/(m.sup.2×hr) or less, and the amount F1 of water permeation into the induction solution is at least 3.5 kg/(m.sup.2×hr).

Provided is a system that can prevent or reduce adhesion of a raw material component to a membrane surface and increase the recovery rate of the raw material component after concentration. A raw material liquid concentration system for a medicine production process is provided with: a forward osmosis membrane unit having a forward osmosis membrane, and a raw material liquid side space and an inductive solution side space which are separated from each other by the forward osmosis membrane; a raw material liquid channel for supplying, to the raw material liquid side space, a raw material liquid containing a solvent and a solute; an inductive solution channel for supplying, to the inductive solution side space, an inductive solution containing an inductive material; a concentrated liquid channel for removing a concentrated raw material liquid from the forward osmosis membrane unit; and a diluted inductive solution channel for removing a diluted inductive solution from the forward osmosis membrane unit. The forward osmosis membrane produces the concentrated raw material liquid and the diluted inductive solution by moving the solvent in the raw material liquid into the inductive solution and by moving the inductive material in the inductive solution into the raw material liquid.

Provided is a composition for forming a separation membrane active layer, the composition comprising a compound of the following Chemical Formula 1 and a compound of the following Chemical Formula 2, wherein a percentage (a/b) of a weight (a) of the compound of Chemical Formula 1 to a weight (b) of the compound of Chemical Formula 2 is 30% to 60%, and a pH thereof is 11 to 12.7:

##STR00001## wherein in Chemical Formulae 1 and 2: R1 to R16 are each independently —CRR′— or —NR″—. at least two of R1 to R10 are —NR″—; at least two of R11 to R16 are —NR″—; and R, R′, and R″ are each independently hydrogen or a substituted or unsubstituted alkyl group; a method for producing a separation membrane; a separation membrane; and a water treatment module.

Provided is a composition for forming a separation membrane active layer, the composition comprising a compound of the following Chemical Formula 1 and a compound of the following Chemical Formula 2, wherein a percentage (a/b) of a weight (a) of the compound of Chemical Formula 1 to a weight (b) of the compound of Chemical Formula 2 is 30% to 60%, and a pH thereof is 11 to 12.7:

##STR00001## wherein in Chemical Formulae 1 and 2: R1 to R16 are each independently —CRR′— or —NR″—. at least two of R1 to R10 are —NR″—; at least two of R11 to R16 are —NR″—; and R, R′, and R″ are each independently hydrogen or a substituted or unsubstituted alkyl group; a method for producing a separation membrane; a separation membrane; and a water treatment module.

The present invention provides enthalpy exchanger elements (E, E′) and enthalpy exchangers comprising such elements. Furthermore, the invention discloses a method for producing such enthalpy exchanger elements and enthalpy exchangers, comprising the steps of a) providing an air-permeable sheet element (1); b) laminating at least one side (1a, 1b) of the sheet element (1) with a thin polymer film (3, 4) with water vapor transmission characteristics; and c) forming the laminated sheet element (1) into a desired shape exhibiting a three-dimensional corrugation pattern (5, 5, . . .).

The present invention provides enthalpy exchanger elements (E, E′) and enthalpy exchangers comprising such elements. Furthermore, the invention discloses a method for producing such enthalpy exchanger elements and enthalpy exchangers, comprising the steps of a) providing an air-permeable sheet element (1); b) laminating at least one side (1a, 1b) of the sheet element (1) with a thin polymer film (3, 4) with water vapor transmission characteristics; and c) forming the laminated sheet element (1) into a desired shape exhibiting a three-dimensional corrugation pattern (5, 5, . . .).