Double layered forward osmosis membrane and preparation method thereof

A technology of forward osmosis membrane and double-skin layer, which is applied in the field of double-skinned forward osmosis membrane and its preparation, can solve problems such as difficulty in membrane thickness, achieve the effect of reducing internal concentration polarization and improving effective water flux

Inactive Publication Date: 2013-04-24
XIAN HHJ WATER TREATMENT TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The thickness of the current forward osmosis membrane is generally between 50-120 microns, but limited by the stren

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Soak the 180-mesh polyester screen with a thickness of 80 microns in about 10% sodium hydroxide solution for about 1 hour to remove the impurities adsorbed on the surface, then wash it with deionized water, and dry it for later use;

[0030] (2) Add 13.1% (V%) triacetate to 52.4% (V%) 1,4-dioxane, 19.7% (V%) acetone, 8.2% (V%) methanol and 6.6% ( V%) in a mixed solvent of lactic acid, heat and stir at 40°C to dissolve, and let it stand for more than 24 hours to completely defoam;

[0031] (3) Immerse the dried support material in the above casting solution for 10 hours, pull it out from the middle of the scrapers on both sides with a gap of 120 microns, volatilize in the air for 30 seconds at room temperature and 90% relative humidity, and then immerse it in Make it gel in deionized water to obtain a double-layered forward osmosis membrane;

[0032] (4) Post-processing:

[0033] Heat-treat the above-mentioned double-skin forward osmosis membrane in a water bath at...

Embodiment 2

[0037] (1) Soak the polyester cloth with a thickness of 60 microns in about 10% sodium hydroxide solution for about 1 hour to remove the impurities adsorbed on the surface, then wash it with deionized water and dry it for later use;

[0038] (2) Add 10.4% (V%) cellulose diacetate to 55.0% (V%) 1,4-dioxane, 19.8% (V%) acetone, 8.2% (V%) methanol and 6.6% ( V%) in a mixed solvent of lactic acid, stir and dissolve at room temperature, and let it stand for more than 24 hours to completely defoam;

[0039] (3) Immerse the dried support material in the above casting solution for 8 hours, pull it out from the middle of the scrapers on both sides with a gap of 100 microns, volatilize in the air for 15 seconds at room temperature and 85% relative humidity, and then immerse it in Make it gel in deionized water to obtain a double-layered forward osmosis membrane;

[0040] (4) Post-processing:

[0041] Heat-treat the above-mentioned double-skin forward osmosis membrane in a water bath a...

Embodiment 3

[0045] (1) Soak the 180-mesh polyester screen with a thickness of 80 microns in about 10% sodium hydroxide solution for about 1 hour to remove the impurities adsorbed on the surface, then wash it with deionized water, and dry it for later use;

[0046] (2) Add 13.9% (V%) triacetate cellulose and diacetate cellulose mixture (mass ratio 1:3) to 52.1% (V%) 1,4-dioxane, 19.2% (V%) In a mixed solvent of acetone, 8.2% (V%) methanol and 6.6% (V%) lactic acid, stir and dissolve at room temperature, and let it stand for more than 24 hours to completely defoam;

[0047] (3) Immerse the dried supporting material in the above casting solution for 12 hours, pull it out from the middle of the scrapers on both sides with a gap of 120 microns, volatilize in the air for 30 seconds at room temperature and 90% relative humidity, and then immerse it in Make it gel in deionized water to obtain a double-layered forward osmosis membrane;

[0048] (4) Post-processing:

[0049] Heat-treat the above-...

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Abstract

The invention discloses a double layered forward osmosis membrane which is characterized by comprising an intermediate porous support layer and ultrathin layers at both sides. A support material such as screen cloth or nonwoven is further embedded in the middle of the porous support layer. The material of the porous support layer and the ultrathin layers is cellulose triacetate fiber, cellulose diacetate fiber or a mixture thereof; and the support material is cotton, polyester or nylon. The preparation method of the double layered forward osmosis membrane includes immersing the processed support material in the film casting solution of cellulose triacetate fiber, cellulose diacetate fiber or the mixture thereof, pulling out from the middle of both sides of a blade, and forming the double layered forward osmosis membrane via a phase inversion method. The advantage of the present invention is that the forward osmosis membrane having two layers can effectively prevent a solute entering into the porous support layer, and reduce the concentration polarization within the support layer, thereby significantly improving the effective water flux of the forward osmosis membrane.

Description

technical field [0001] The invention belongs to the technical field of polymer separation membranes, and in particular relates to a double-skin forward osmosis membrane and a preparation method thereof. Background technique [0002] Forward osmosis technology, as a new membrane separation technology, has developed rapidly in recent years, and has aroused extensive interest of researchers at home and abroad for its outstanding advantages such as low energy consumption, low membrane pollution, and high rejection rate. And desalination, food and medicine, and energy have been used in a series of fields. [0003] However, the lack of high-performance forward osmosis membrane is an important obstacle restricting the development of forward osmosis technology. An ideal forward osmosis membrane should have a denser skin layer with a high rejection rate for solutes and a thinner, looser and more porous support layer to reduce internal concentration polarization. The internal concen...

Claims

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Application Information

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IPC IPC(8): B01D69/10B01D67/00
Inventor 王铎许春玲苏燕汪锰
Owner XIAN HHJ WATER TREATMENT TECH
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