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Method for preparing reverse osmosis membrane

A reverse osmosis membrane and cross-linking reaction technology, applied in reverse osmosis, semi-permeable membrane separation, chemical instruments and methods, etc., can solve PVA coating damage, reverse osmosis membrane water flux decline, loss of protection and anti-pollution, etc. problems, achieve the effect of small water flux, improve mechanical properties, improve water erosion resistance and water dissolution resistance

Inactive Publication Date: 2018-01-09
宁波日新恒力科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] During the rolling and use of existing reverse osmosis membranes, the surface of the polyamide separation layer is generally coated with a layer of PVA cross-linked layer, which plays the role of protection and anti-pollution, but the PVA coating will follow the water flow. The scouring and dissolution of water is slowly destroyed, and finally loses its protective and anti-pollution effects
The prior art improves the degree of cross-linking of PVA coatings by increasing the concentration of reactants to increase the degree of cross-linking of PVA coatings. Although this method improves the water erosion resistance and water dissolution resistance of PVA coatings, the reverse osmosis membrane The water flux will be greatly reduced, seriously affecting the separation performance of the membrane

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-4

[0032] The degree of polymerization is 1000, the degree of alcoholysis is 99% PVA dissolved in the aqueous solution of 80 ℃, the mass fraction of PVA is 8%, after stirring evenly, add the polyarylate fiber of different fineness (as shown in table 1), The content is 0.01wt%, magnetic stirring and ultrasonic dispersion for 20 minutes, then add 0.6wt% glutaraldehyde and 0.2wt% hydrochloric acid, magnetic stirring and ultrasonic dispersion for 25min. The reaction solution was coated on the polyamide layer of the reverse osmosis membrane prepared in Comparative Example 1, and put into an oven at 100° C. for 10 minutes to react to obtain a reverse osmosis membrane modified by PVA coating containing polyarylate fibers. The desalination rate and water flux of the obtained reverse osmosis membrane were tested, and the test results are shown in Table 1.

[0033] As can be seen from the following table 1, the preferred embodiment in this example is that the degree of polymerization of th...

Embodiment 5-8

[0038] The degree of polymerization is 1000, the degree of alcoholysis is 99% PVA dissolved in the aqueous solution of 80 ℃, the mass fraction of PVA is 8%, after stirring evenly, add the polyarylate fiber of different fineness (as shown in table 2), The content is 0.03wt%, magnetic stirring and ultrasonic dispersion for 20 minutes, then add 0.6wt% glutaraldehyde and 0.2wt% hydrochloric acid, magnetic stirring and ultrasonic dispersion for 25 minutes. The reaction solution was coated on the polyamide layer of the reverse osmosis membrane prepared in Comparative Example 1, and put into an oven at 100° C. for 10 minutes to react to obtain a reverse osmosis membrane modified by PVA coating containing polyarylate fibers. The desalination rate and water flux of the obtained reverse osmosis membrane were tested, and the test results are shown in Table 2.

[0039]As can be seen from the following table 2, the preferred implementation in this example is that the degree of polymerizati...

Embodiment 9-12

[0044] The degree of polymerization is 1000, the degree of alcoholysis is 99% of the PVA dissolved in the aqueous solution of 80 ℃, the mass fraction of PVA is 8%, after stirring evenly, add polyarylate fibers of different fineness (as shown in table 3), The content is 0.05wt%, magnetic stirring and ultrasonic dispersion for 20 minutes, then add 0.6wt% glutaraldehyde and 0.2wt% hydrochloric acid, magnetic stirring and ultrasonic dispersion for 25 minutes. The reaction solution was coated on the polyamide layer of the reverse osmosis membrane prepared in Comparative Example 1, and put into an oven at 100° C. for 10 minutes to react to obtain a reverse osmosis membrane modified by PVA coating containing polyarylate fibers. The desalination rate and water flux of the obtained reverse osmosis membrane were tested, and the test results are shown in Table 3.

[0045] As can be seen from the following table 3, the preferred implementation in this example is that the degree of polymer...

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PUM

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Abstract

The invention discloses a method for preparing a reverse osmosis membrane. The method comprises the following steps: (1) preparation of a PVA (Polyvinyl Alcohol) aqueous solution, dissolving PVA withmass fraction of 0.5-25wt% in 50-90 DEG C water, stirring evenly and then adding a polyarylate fiber with mass fraction of 0.01wt%-1wt%, magnetically stirring and ultrasonically dispersing for 10-20min respectively; (2) preparation of a PVA cross-linking reaction solution, adding a crosslinking agent and an acid catalyst in the PVA aqueous solution, magnetically stirring and ultrasonically dispersing for 10-20min respectively; (3) crosslinking reaction: coating a reverse osmosis membrane with the PVA cross-linking reaction solution, and placing in a 60-120 DEG C oven to react for 5-20min to obtain a polyarylate fiber-containing PVA coating modified reverse osmosis membrane. In the method provided by the invention, the polyarylate fiber used as a reinforcing material is introduced into thesurface of a polyamide layer for PVA coating modification, so that the water scour resistance and water solubility resistance of the PVA coating are improved, and the effect on water flux of the reverse osmosis membrane is little.

Description

technical field [0001] The invention relates to a method for modifying a reverse osmosis membrane, in particular to a preparation method for a reverse osmosis membrane. Background technique [0002] Reverse osmosis is an efficient water purification method, which has the advantages of high efficiency, low cost, no phase change, easy integration, modularization and automation, etc. It is widely used in the preparation of high-purity water in the electronics industry, medical water preparation, seawater desalination, Water desalination, sewage recycling and many other fields. With the shortage of global fresh water resources and the increasingly serious water pollution, reverse osmosis technology is playing an increasingly important role in water purification. [0003] During the rolling and use of existing reverse osmosis membranes, the surface of the polyamide separation layer is generally coated with a layer of PVA cross-linked layer, which plays the role of protection and...

Claims

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Application Information

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IPC IPC(8): B01D67/00B01D69/02B01D71/56B01D61/02
Inventor 不公告发明人
Owner 宁波日新恒力科技有限公司