Hydrophilic polyamide reverse osmosis membrane with compact surface as well as preparation method and application thereof

A technology of reverse osmosis membrane and polyamide, used in reverse osmosis, semi-permeable membrane separation, chemical instruments and methods, etc., can solve problems such as membrane water flux decline

Pending Publication Date: 2020-07-21

TSINGHUA UNIV

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AI-Extracted Technical Summary

Problems solved by technology

However, the above methods will cause a rapi...

Method used

A kind of method of intercepting boric acid in nuclear power plant liquid effluent comprises the following steps: reverse osmosis membrane (polyamide commercial reverse osmosis membrane LE) is placed in 25% isopropanol solution and soaks 20 minutes, uses after Wash 6 times with deionized water, 30 minutes each time, store in deionized water at 4°C; then place the reverse osmosis membrane in the modified tank, cover with carbodiimide solution for 10 minutes, and then add N-hydroxysuccinyl Imine solution, after covering for 50 minutes, pour out the waste liquid, clean the reverse osmosis membrane with deionized water for 2 times; then use the concentration of reverse osmosis membrane as 5%, branched polyethyleneimine (branching degree is 60%) ratio The 50% solution was covered for 12 hours, and light-shielding treatment was carried out during the process, and then the waste liquid was poured out, and the membrane was washed twice with deionized water to obtain a polyethyleneimine-grafted reverse osmosis membrane. Next, the reverse osmosis membrane was placed in an aqueous solution with a glutaraldehyde concentration of 1.4%, and the cross-linking reaction time was 12 hours to obtain a reverse osmosis membrane with a denser surface.

A...

Abstract

The invention relates to a hydrophilic polyamide reverse osmosis membrane with a compact surface as well as a preparation method and application thereof. Specifically, the invention relates to a hydrophilic polyamide reverse osmosis membrane with a compact surface, comprising a polyamide base membrane and a crosslinked polyethyleneimine layer grafted to the polyamide base membrane, wherein the crosslinked polyethyleneimine layer is formed from a polyethyleneimine blend comprising branched polyethyleneimine, and the degree of branching of the branched polyethyleneimine is between 55% and 65%. The invention also relates to the preparation method of the reverse osmosis membrane and application of the reverse osmosis membrane in separating boric acid from liquid effluent of a nuclear power plant.

Application Domain

MembranesReverse osmosis +3

Technology Topic

Cross-linked polyethylenePolyamide +7

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Examples

Experimental program(8)
Comparison scheme(1)

Example Embodiment

[0038] Example 1:

[0039] A method for intercepting boric acid in the liquid effluent of nuclear power plants, including the following steps: immerse a reverse osmosis membrane (polyamide-based commercial reverse osmosis membrane LE) in a 25% isopropanol solution for 20 minutes, and then rinse with deionized water 6 times, 30 minutes each time, store in deionized water at 4℃; then place the reverse osmosis membrane in the modification tank, first cover with carbodiimide solution for 10 minutes, then add N-hydroxysuccinimide solution , After covering for 50 minutes, discard the waste liquid, clean the reverse osmosis membrane twice with deionized water; then use the reverse osmosis membrane with a concentration of 5% and a branched polyethyleneimine (branching degree of 60%) with a ratio of 100% The solution was covered for 12 hours, and shading was performed during the process. After that, the waste liquid was discarded, and the membrane was washed twice with deionized water to obtain a polyethyleneimine grafted reverse osmosis membrane.

[0040] The modified reverse osmosis membrane was dried, and after analysis and testing, the Zeta potential on the surface of the reverse osmosis membrane changed from negative to positive. Then the modified reverse osmosis membrane is installed in the membrane testing device for testing. The concentration of nuclides Cs and Co in the simulated waste liquid is 2000ppb, the concentration of boric acid is 500ppm, the test condition is that the pressure is 1.2MPa, and the flow rate is 0.4m/s. , The temperature is 25℃. The results showed that radionuclide ions and boric acid were trapped by the membrane and could not enter the membrane permeate. The separation efficiency of the modified membrane for boric acid increased from 49.46% to 62.13%.

[0041] The treated membrane is loaded into the membrane element and integrated into a membrane system. During the treatment process, the boron-containing radioactive waste liquid produced by the nuclear power plant enters the membrane system. Taking the two-stage reverse osmosis system as an example, the removal efficiency of boric acid reaches over 85%. The concentrated solution enriched with a large amount of boric acid and radionuclide ions can be reused or stored after solidification. The curing treatment method includes cement curing, drying in a barrel, etc., and the curing treatment can also be performed after the resin is concentrated and enriched/or after further evaporation and concentration.

Example Embodiment

[0042] Example 2:

[0043] A method for intercepting boric acid in the liquid effluent of nuclear power plants, including the following steps: immerse a reverse osmosis membrane (polyamide-based commercial reverse osmosis membrane LE) in a 25% isopropanol solution for 20 minutes, and then rinse with deionized water 6 times, 30 minutes each time, store in deionized water at 4℃; then place the reverse osmosis membrane in the modification tank, first cover with carbodiimide solution for 10 minutes, then add N-hydroxysuccinimide solution , After covering for 50 minutes, discard the waste liquid, wash the reverse osmosis membrane twice with deionized water; then use the reverse osmosis membrane with a concentration of 5% and a branched polyethyleneimine (branching degree of 60%) ratio of 70% The solution was covered for 12 hours, and shading was performed during the process. After that, the waste liquid was discarded, and the membrane was washed twice with deionized water to obtain a polyethyleneimine grafted reverse osmosis membrane.

[0044] The modified reverse osmosis membrane was dried, and after analysis and testing, the Zeta potential on the surface of the reverse osmosis membrane changed from negative to positive. Then the modified reverse osmosis membrane is installed in the membrane testing device for testing. The concentration of nuclides Cs and Co in the simulated waste liquid is 2000ppb, the concentration of boric acid is 500ppm, the test condition is that the pressure is 1.2MPa, and the flow rate is 0.4m/s. , The temperature is 25℃. The results showed that radionuclide ions and boric acid were trapped by the membrane and could not enter the membrane permeate. The separation efficiency of the modified membrane for boric acid increased from 49.46% to 63.76%.

[0045] The treated membrane is loaded into the membrane element and integrated into a membrane system. During the treatment process, the boron-containing radioactive waste liquid produced by the nuclear power plant enters the membrane system. Taking the two-stage reverse osmosis system as an example, the removal efficiency of boric acid is over 86%. The concentrated solution enriched with a large amount of boric acid and radionuclide ions can be reused or stored after solidification. The curing treatment method includes cement curing, drying in a barrel, etc., and the curing treatment can also be performed after the resin is concentrated and enriched/or after further evaporation and concentration.

Example Embodiment

[0046] Example 3:

[0047] A method for intercepting boric acid in the liquid effluent of nuclear power plants, including the following steps: immerse a reverse osmosis membrane (polyamide-based commercial reverse osmosis membrane LE) in a 25% isopropanol solution for 20 minutes, and then rinse with deionized water 6 times, 30 minutes each time, store in deionized water at 4℃; then place the reverse osmosis membrane in the modification tank, first cover with carbodiimide solution for 10 minutes, then add N-hydroxysuccinimide solution , After covering for 50 minutes, discard the waste liquid, wash the reverse osmosis membrane twice with deionized water; then use the reverse osmosis membrane with a concentration of 5% and branched polyethyleneimine (branching degree of 60%) to 50% The solution was covered for 12 hours, and shading was performed during the process. Afterwards, the waste liquid was discarded, and the membrane was washed twice with deionized water to obtain a polyethyleneimine grafted reverse osmosis membrane.

[0048] The modified reverse osmosis membrane was dried, and after analysis and testing, the Zeta potential on the surface of the reverse osmosis membrane changed from negative to positive. Then the modified reverse osmosis membrane is installed in the membrane testing device for testing. The concentration of nuclides Cs and Co in the simulated waste liquid is 2000ppb, the concentration of boric acid is 500ppm, the test condition is that the pressure is 1.2MPa, and the flow rate is 0.4m/s. , The temperature is 25℃. The results showed that radionuclide ions and boric acid were trapped by the membrane and could not enter the membrane permeate. The separation efficiency of the modified membrane for boric acid was increased from 49.46% to 64.04%.

[0049] The treated membrane is loaded into the membrane element and integrated into a membrane system. In the treatment process, the boron-containing radioactive waste liquid produced by the nuclear power plant enters the membrane system. Taking the two-stage reverse osmosis system as an example, the removal efficiency of boric acid reaches more than 87%. The concentrated solution enriched with a large amount of boric acid and radionuclide ions can be reused or stored after solidification. The curing treatment methods include cement curing, drying in the barrel, etc., and the curing treatment can also be carried out after the resin is concentrated and enriched/or after further evaporation and concentration.

PUM

Property	Measurement	Unit
Water contact angle	<= 53.0	deg
Weight average molecular weight	20000.0 ~ 30000.0
Weight average molecular weight	60000.0 ~ 80000.0

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