High-water-flux forward-osmosis composite membrane and preparation method thereof

A technology of forward osmosis and composite membrane, which is applied in the field of membrane separation, can solve problems such as being unsuitable for the forward osmosis process, achieve the effect of weakening concentration polarization, increasing water permeation flux, and maintaining stability

Active Publication Date: 2014-08-13
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the main function of the porous support layer in the design of the reverse osmosis membrane is only to act as a support carrier for the active separation layer, it is not suitable for the forward osmosis process.

Method used

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  • High-water-flux forward-osmosis composite membrane and preparation method thereof
  • High-water-flux forward-osmosis composite membrane and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 1. Mix polyethersulfone, sulfonated polysulfone, N,N-dimethylacetamide and N-methylpyrrolidone according to the ratio of parts by weight 13:2:40:45, heat and stir, stand still or vacuum Prepare the membrane solution by degassing, then scrape it on a clean and flat glass plate to form a flat membrane, and then phase transform it into a porous membrane in water, the thickness of the membrane is about 100 microns.

[0021] 2. Soak the flat membrane prepared in step 1 in deionized water at room temperature for no less than 24 hours, fully wash away the solvent in the membrane pores, take it out, wash it with deionized water for 2 to 3 times, and blow it with compressed air. Sweep the surface of the film until there is no obvious water stain or dry it at room temperature in a clean environment.

[0022] 3. Fix the porous membrane dried in step 2 in the frame, and pour the aqueous solution containing polyamine monomer on the denser cortex of the porous membrane, that is, the ...

Embodiment 2

[0025] Mix polyethersulfone, sulfonated polysulfone, montmorillonite, N,N-dimethylacetamide and N-methylpyrrolidone according to the ratio of parts by weight 13:2:0.15:40:45, heat and stir, Stand still or vacuum defoaming to prepare the membrane solution, then scrape it into a flat membrane on a clean and flat glass plate with a scraper, and then phase invert into a porous membrane in water, with a membrane thickness of about 100 microns. All the other steps are the same as in Example 1. The cross-sectional pore structure of the porous layer is uniform, the pore size distribution of the cortex is uniform, and there is no macropore defect. The microscopic morphology of the porous support layer is as follows figure 1 shown.

[0026] For the forward osmosis membrane prepared in this embodiment, under the same test conditions as in Example 1, the water permeation flux is 24.2L / m 2 h, the reverse leakage flux of salt is 3.4g / m 2 h. Under the same test conditions, the standard ...

Embodiment 3

[0028] Mix polyethersulfone, sulfonated polysulfone, montmorillonite, N,N-dimethylacetamide and N-methylpyrrolidone according to the ratio of parts by weight 13:2:0.15:40:45, heat and stir, Stand still or vacuum defoaming to prepare membrane solution. Moisten the 250-mesh polyester mesh with solvent, fix it on a clean, flat glass plate, and let it dry at room temperature. Then pour the film-casting solution on the mesh cloth and scrape it into a flat film with a scraper, and then phase transform it into a porous film in water. The total thickness of the film is about 100 microns. All the other steps are the same as in Example 1.

[0029] Forward osmosis membrane prepared in this example, the microscopic morphology is as follows figure 2 shown. Under the same test conditions as in Example 1, the water permeation flux is 22L / m 2h, the reverse leakage flux of salt is 4.7g / m 2 h. The forward osmosis membrane obtained by this embodiment not only has the characteristics of hi...

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Abstract

The invention relates to a high-water-flux forward-osmosis composite membrane and a preparation method thereof. The forward-osmosis composite membrane is a polysulfone-sulfonated polysulfone-inorganic filler blended/polyamide composite membrane. A traditional osmosis membrane is generally applied to a reverse-osmosis system, and if the traditional osmosis membrane is used in a forward-osmosis process, the water flux of osmosis is far lower than a theoretical value since the traditional osmosis composite membrane is large in thickness, the hydrophilicity of a supporting layer of a polyamide layer is poor so as to cause serious inner concentration polarization. The preparation method comprises the following steps: blending a polymer with a modifier to form film casting liquid; after scraping or leveling, performing non-solvent coagulating bath with water; by a phase-inversion method, preparing a polysulfone ultrafiltration membrane with good hydrophilicity, high porosity, uniform surface pore structure and narrow pore diameter distribution; and in a clean environment and at room temperature, airing the polysulfone membrane till the surface is dry, and growing a polyamide active layer on the surface of the polysulfone membrane by an interfacial polymerization method, thereby obtaining the forward-osmosis composite membrane with good hydrophilicity, high porosity, low thickness and high mechanical strength. The high-water-flux forward-osmosis composite membrane disclosed by the invention has the advantages that not only the osmosis flux is high, but also the reverse leakage of an extraction medium is low, and the selective permeability is good.

Description

technical field [0001] The invention belongs to the field of membrane separation, and specifically relates to a high water flux forward osmosis composite membrane and a preparation method thereof. The forward osmosis composite membrane is a polymer / hydrophilic polymer / inorganic filler blend as a support layer, The polyamide layer is a forward osmosis composite membrane with an active separation layer. Background technique [0002] Forward osmosis is a ubiquitous phenomenon in nature. It can be carried out spontaneously without providing additional energy as long as there is an osmotic pressure difference on both sides of the semipermeable membrane. In recent years, as people pay more and more attention to energy and environment, the forward osmosis membrane separation process has attracted widespread attention as a green separation and power generation process with great potential. Although studies have shown that compared with traditional pressure separation membranes, for...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/68B01D71/66B01D69/12B01D67/00
Inventor 徐铜文王亚琴
Owner UNIV OF SCI & TECH OF CHINA
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