Composite semi-permeable membrane

Patent metadata

Field	Value
Publication number	US-12318738-B2
Application number	US-202017772608-A
Country	US
Kind code	B2
Filing date	Oct 30, 2020
Priority date	Oct 31, 2019
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

The present invention relates to a composite semipermeable membrane including: a support membrane including a base and a porous support layer; and a separation functional layer disposed on the porous support layer and including a crosslinked aromatic polyamide, in which the separation functional layer contains sulfo groups in an amount of 7.0×10−5 to 5.0×10−2 g/m2 and includes a structure represented by the formula 1.

First claim

The invention claimed is:

1. A composite semipermeable membrane comprising:
a support membrane comprising a base and a porous support layer; and
a separation functional layer disposed on the porous support layer and comprising a crosslinked aromatic polyamide,
wherein the separation functional layer contains sulfo groups in an amount of 7.0×10 −5 to 5.0×10 −2 g/m 2 and includes a structure represented by the following formula 1:

provided that
R 1 is a hydrogen atom or a hydrocarbon having a carbon number of 1 to 10 and optionally having a substituent,
R 2 to R 5 are each a hydrogen atom or a hydrocarbon having a carbon number of 1 to 10,
Ar 1 to Ar 3 are each an aromatic ring having a carbon number of 6 to 14 and optionally having a substituent, and
at least one of R 1 , Ar 1 , Ar 2 , and Ar 3 includes a sulfo group; and
wherein the separation functional layer has a zeta potential at pH 3 of −5 mV or lower.

2. The composite semipermeable membrane according to claim 1 , wherein the separation functional layer comprises a pleated thin membrane,
the thin membrane has an average thickness of 10 nm-20 nm, and
the separation functional layer has a nitrogen-atom surface density, as determined by Rutherford backscattering spectrometry (RBS), of 4.0×10 20 to 1.2×10 21 atoms/m 2 .

3. The composite semipermeable membrane according to claim 1 , wherein a compound having a structure represented by the following formula 2 is present in the separation functional layer:

provided that X and Y are each a nitrogen atom, an oxygen atom, or a hydrocarbon,
R 6 is a hydrogen atom or a hydrocarbon having a carbon number of 1 to 10, and R 7 is a hydrocarbon having a carbon number of 2 to 4.

4. The composite semipermeable membrane according to claim 1 , wherein R 1 in formula 1 is a hydrocarbon having a carbon number of 1 or 2 and having at least one sulfo group.

5. The composite semipermeable membrane according to claim 1 , wherein Ar 2 in formula 1 is an aromatic ring having a carbon number of 6 to 14 and having at least one sulfo group.

6. The composite semipermeable membrane according to claim 1 , wherein the separation functional layer has a C/D ratio value of 3 to 10,
provided that,
A is the number of sulfo-group-derived sulfur atoms as determined by X-ray photoelectron spectroscopy (XPS),
B is the total number of nitrogen atoms as determined by XPS,
C is the A/B ratio as determined by examining a surface of the separation functional layer in the composite semipermeable membrane, and
D is the A/B ratio as determined by examining a solid obtained by molding a powder of the separation functional layer extracted from the composite semipermeable membrane.

Assignees

• Toray Industries

Inventors

• Yasuda Takaaki
• Adachi Yohei
• Mitsui Shinya
• Shimura Harutoki
• Ogawa Takafumi

Classifications

• B01D69/1213

  Laminated layers · CPC title

• B01D2325/36

  Hydrophilic membranes · CPC title

• B01D2325/26

  Electrical properties · CPC title

• B01D2325/06

  Surface irregularities · CPC title

• B01D2325/04

  Characteristic thickness · CPC title