Abstract:
A composite semipermeable membrane which satisfies the following relationship when seawater at 25 DEG C having a pH of 6.5, a boron concentration of 5 ppm and a TDS concentration of 3.5% by weight is permeated under an operation pressure of 5.5 MPa: Boron removal ratio (%) ≥ 95 - 4 x membrane permeation flow rate (m /m •day).
Abstract:
Provided is a composite semipermeable membrane having a polyamide separation-functional layer on a porous support layer, wherein the polyamide separation-functional layer has a yellow index of 10 to 40, and the actual length of the polyamide separation-functional layer per 1 µm-length of the porous support layer is from 2 µm to 5 µm, or a composite semipermeable membrane having on a porous support layer a polyamide separation-functional layer prepared by polycondensation of polyfunctional amines with polyfunctional acid halides, wherein the polyamide separation-functional layer is formed by the steps of (A) interfacial polycondensation in which polyfunctional amines and polyfunctional acid halides are brought into contact at 40°C to 70°C and subsequent (B) heat treatment at 70°C to 150°C. The composite semipermeable membrane according to the present invention has high boron removal performance and high water permeation performance.
Abstract:
The present invention provides a semipermeable membrane which has resistance to oxidizing agents even in the presence of heavy metals and which, despite this, can have salt-removing performance equal to that of semipermeable membranes having poor resistance to oxidizing agents. A coated semipermeable membrane of the invention includes a semipermeable layer and a polymer layer formed on the semipermeable layer, and the polymer layer includes a polymerization product formed by both condensation of hydrolyzable groups possessed by the following compound (A) and polymerization of the compound (A) with the following compound (B): (A) a silicon compound having a silicon atom, a reactive group including an ethylenically unsaturated group directly bonded to the silicon atom, and a hydrolyzable group directly bonded to the silicon atom; and (B) a compound other than the compound (A), which has both a hydrophilic group and an ethylenically unsaturated group.
Abstract:
The problem to be solved by the present invention is to provide a separation membrane having excellent separation performance and permeation performance, having high membrane strength, and mainly including a cellulose-based resin. The present invention relates to a separation membrane containing a cellulose ester and having a tensile elasticity of 1,500 to 6,500 MPa.
Abstract:
Provided is a production process for a semipermeable membrane having both semipermeability and strength and also provided is the semipermeable membrane. The process comprises the step of forming a liquid membrane from a membrane-forming solution comprising materials (A) to (C), material (A) being a polymer having a repeating unit structure comprising one or more kinds of structural moieties selected from the group consisting of an amide group, an imide group, a sulfonyl group, and a heterocyclic ring, material (B) being a good solvent for material (A), material (C) being a salt, and the step of removing the solvent from the liquid membrane.