Separation membrane, separation membrane element and separation membrane module

Patent metadata

Field	Value
Publication number	US-10814289-B2
Application number	US-201515516969-A
Country	US
Kind code	B2
Filing date	Oct 6, 2015
Priority date	Oct 7, 2014
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

[Problem] To provide a membrane for the forward osmosis method, which keeps a high porosity, reduces concentration polarization by appropriately controlling the pore distribution, achieves both high water permeability and a self-supporting property, and has high chemical durability such that are membrane is applicable to various draw solutions. [Solution] A separation membrane having a structure inclined from an outer surface side to an inner surface side, a ratio between a thickness of a dense layer having a dense polymer density and a thickness of a coarse layer having a coarse polymer density being in a range of 0.25≤(the thickness of the coarse layer)/[(the thickness of the dense layer)+(the thickness of the coarse layer)]≤0.6, when measuring polymer density distribution in a thickness direction of the separation membrane by Raman spectroscopy.

First claim

The invention claimed is:

1. A separation membrane having a density gradient from an outer surface side to an inner surface side,
a ratio between a thickness of a dense layer having a dense polymer density and a thickness of a coarse layer having a coarse polymer density being in a range of 0.25≤(the thickness of the coarse layer)/[(the thickness of the dense layer)+(the thickness of the coarse layer)]≤0.6, when measuring polymer density distribution in a thickness direction of the separation membrane by Raman spectroscopy, and wherein
the coarse polymer density increases toward the dense layer,
the separation membrane comprises sulfonated poly(arylene ether) having a repeating structure of a hydrophobic segment represented by the following formula (I) and a hydrophilic segment represented by the following formula (II):

where m and n each represents a natural number equal to or greater than 1, R 1 and R 2 represent —SO 3 M, M represents a metal element, and a ratio of sulfonation expressed as a percentage of the number of repetition of the formula (II) to a total of the number of repetition of the formula (I) and the number of repetition of the formula (II) in the sulfonated poly(arylene ether) copolymer is higher than 10% and lower than 50%.

2. The separation membrane according to claim 1 , wherein
a porosity of the separation membrane is 60 to 85%.

3. The separation membrane according to claim 1 , wherein
the separation membrane is for forward osmosis treatment.

4. The separation membrane according to claim 1 , wherein
the separation membrane is a hollow fiber membrane.

5. A separation membrane element having the separation membrane as recited in claim 1 incorporated therein.

6. A separation membrane module having one or more separation membrane elements as recited in claim 5 incorporated therein.

Assignees

• Toyo Boseki

Inventors

• Nakao Takahito
• Akashi Mayumi
• Yao Miyuki
• Watanuki Seiji
• Kitagawa Tooru

Classifications

• B01D61/0021

  comprising multiple forward osmosis steps · CPC title

• B01D69/1218

  Layers having the same chemical composition, but different properties, e.g. pore size, molecular weight or porosity · CPC title

• B01D63/02

  Hollow fibre modules · CPC title

• B01D71/52 Primary

  Polyethers · CPC title

• C08G65/4056

  (I) or (II) containing sulfur (as the sulfone group C08G75/23) · CPC title