阅读说明：本技术 耐氯氨基酸修饰聚醚砜反渗透膜及制备方法 (Chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane and preparation method thereof ) 是由 孟建强 尤蒙 于 2021-01-31 设计创作，主要内容包括：本发明公开了一种耐氯氨基酸修饰聚醚砜反渗透膜及制备方法,制备包括：1)双键聚醚砜的合成；2)氨基酸修饰聚醚砜的合成；3)耐氯氨基酸修饰聚醚砜反渗透膜的制备：将氨基酸修饰聚醚砜和聚砜类聚合物溶解在有机溶剂中配置成铸膜液,静置脱泡,然后倾倒在干净的玻璃板上刮膜,空气中挥发,然后沉浸于凝固浴中成膜,得到耐氯氨基酸修饰聚醚砜反渗透膜。经测试结果表明,本发明制备的耐氯氨基酸修饰聚醚砜反渗透膜具有较高的分离性能和优异的耐氯性能。(The invention discloses a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane and a preparation method thereof, wherein the preparation method comprises the following steps: 1) synthesizing double-bond polyether sulfone; 2) synthesizing amino acid modified polyether sulfone; 3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane: dissolving amino acid modified polyether sulfone and polysulfone polymers in an organic solvent to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate to scrape a membrane, volatilizing in air, and immersing in a coagulating bath to form a membrane to obtain the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane. The test result shows that the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane prepared by the invention has higher separation performance and excellent chlorine resistance.)

1. A preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is characterized by comprising the following steps:

1) synthesizing double-bond polyether sulfone:

adding 1-10mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone, 1-10mmol of 4,4 '-dihydroxydiphenyl sulfone, 2-20mmol of 4,4' -difluorodiphenyl sulfone, 1-30mmol of alkali metal carbonate and 50-100mL of a first organic solvent into a container according to the proportion, introducing nitrogen, heating to the temperature of 110-150 ℃, reacting for 2-5h, removing water, heating to the temperature of 170-200 ℃, reacting for 2-24h to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone;

2) synthesis of amino acid modified polyether sulfone:

according to the proportion, 1-5g of the double-bond polyether sulfone obtained in the step 1), 0.1-2.0g of sulfhydryl-containing amino acid or sulfhydryl-containing amino acid salt, 0.1-1g of DMPA and 10-50mL of a second organic solvent are stirred and dissolved, nitrogen is introduced, an ultraviolet light source with the wavelength of 365nm is used for irradiation, the irradiated solution is added into deionized water, precipitation and filtration are carried out to obtain a solid, the solid is washed by the deionized water and ethanol in sequence, and the solid is dried in a vacuum oven at the temperature of 30-50 ℃ for 24-48h to obtain amino acid modified polyether sulfone;

DMPA is shorthand for 2, 2-dimethoxy-2-phenylacetophenone;

3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane: dissolving 1-5g of the amino acid modified polyether sulfone obtained in the step 2) and 0-10g of polysulfone polymer in 40-100mL of third organic solvent according to a proportion to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate for membrane scraping, volatilizing the membrane in the air for 0-120s, and immersing the membrane casting solution in a coagulating bath at 0-40 ℃ for membrane forming to obtain the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

2. The process as claimed in claim 1, wherein the alkali metal carbonate is K₂CO₃And Na₂CO₃At least one of them.

3. The process as set forth in claim 1 wherein the first organic solvent is at least two of N-methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, sulfolane, dimethylsulfoxide and toluene.

4. The method according to claim 1, wherein the thiol-group-containing amino acid is DL-mercaptobuthionine or N-acetylcysteine, and the thiol-group-containing amino acid salt is DL-cysteine hydrochloride.

5. The method as set forth in claim 1, wherein the second organic solvent is at least one of tetrahydrofuran, N-dimethylacetamide, N-dimethylformamide, N-methylpyrrolidone, dimethylsulfoxide and acetone.

6. The method as set forth in claim 1, wherein the polysulfone-based polymer in the step 3) is 1-9 g.

7. The method according to claim 1 or 6, wherein the polysulfone-based polymer is polysulfone, sulfonated polysulfone, polyethersulfone, sulfonated polyethersulfone or double-bonded polyethersulfone obtained in step 1).

8. The method of claim 1, wherein the third organic solvent is at least one of tetrahydrofuran, N, N-dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone, acetone, and dimethylsulfoxide.

9. The method of claim 1, wherein the coagulation bath is at least one of water, N-dimethylacetamide, dimethylsulfoxide, and N-methylpyrrolidone.

10. The chlorine-resistant amino acid modified polyethersulfone reverse osmosis membrane prepared by the method of any one of claims 1-9.

Technical Field

The invention relates to the field of reverse osmosis membrane preparation technology and application, in particular to a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane and a preparation method thereof.

Background

The reverse osmosis technology is one of important technologies for solving the shortage of water resources, has the advantages of high separation efficiency, low energy consumption, small occupied area, simple and convenient operation, no secondary pollution and the like, and is widely applied to the fields of drinking water, river water, industrial water, brackish water, seawater desalination and purification and the like. Currently, aromatic polyamide reverse osmosis composite membranes, which are the mainstream reverse osmosis membranes, have high water flux and salt rejection, but the wide application and long-term use thereof are limited due to the poor membrane fouling and chlorine resistance. The aromatic polyamide reverse osmosis membrane is prepared from polyamine and polybasic acyl chloride by an interfacial polymerization method, and amido bonds in a chemical structure of the aromatic polyamide reverse osmosis membrane are easily attacked by active chlorine to cause rapid attenuation of membrane performance. Chlorine is used as a bactericide, chlorination treatment is carried out in the pretreatment process of the reverse osmosis membrane, which is an important means for solving microbial pollution, and in order to protect a polyamide layer from being damaged, dechlorination treatment is required to be carried out on inlet water of the reverse osmosis system in actual operation, so that a large amount of capital waste and energy consumption are caused.

The polysulfone polymer has good mechanical property, thermal stability and chemical stability, has no amide bond which is easy to be attacked by chlorine in the structure, and can be used for preparing the chlorine-resistant reverse osmosis membrane. But the water flux of the prepared membrane is lower because the polysulfone polymer has strong hydrophobicity. Hydrophilic modification is one of the most important modification methods for changing the hydrophilicity and the hydrophobicity of the polymer, and hydrophilic groups are introduced into the polysulfone polymer, so that the hydrophilicity of the polymer can be improved, and the separation performance of the polymer can be improved. Generally, the hydrophilization modification of the polymer usually requires multi-step reaction, the preparation process is complex, the reaction time is long, and the reaction conditions are harsh.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

The invention also provides a preparation method of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

The technical scheme of the invention is summarized as follows:

a preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane comprises the following steps:

1) synthesizing double-bond polyether sulfone:

adding 1-10mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone, 1-10mmol of 4,4 '-dihydroxydiphenyl sulfone, 2-20mmol of 4,4' -difluorodiphenyl sulfone, 1-30mmol of alkali metal carbonate and 50-100mL of a first organic solvent into a container according to the proportion, introducing nitrogen, heating to the temperature of 110-150 ℃, reacting for 2-5h, removing water, heating to the temperature of 170-200 ℃, reacting for 2-24h to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone;

2) synthesis of amino acid modified polyether sulfone:

according to the proportion, 1-5g of the double-bond polyether sulfone obtained in the step 1), 0.1-2.0g of sulfhydryl-containing amino acid or sulfhydryl-containing amino acid salt, 0.1-1g of DMPA and 10-50mL of a second organic solvent are stirred and dissolved, nitrogen is introduced, an ultraviolet light source with the wavelength of 365nm is used for irradiation, the irradiated solution is added into deionized water, precipitation and filtration are carried out to obtain a solid, the solid is washed by the deionized water and ethanol in sequence, and the solid is dried in a vacuum oven at the temperature of 30-50 ℃ for 24-48h to obtain amino acid modified polyether sulfone;

DMPA is shorthand for 2, 2-dimethoxy-2-phenylacetophenone;

3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane: dissolving 1-5g of the amino acid modified polyether sulfone obtained in the step 2) and 0-10g of polysulfone polymer with the weight-average molecular weight of 20,000-600,000g/mol in 40-100mL of third organic solvent according to a proportion to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate for membrane scraping, volatilizing the membrane for 0-120s in the air, and immersing the membrane casting solution in a coagulating bath at 0-40 ℃ for membrane forming to obtain the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

Alkali metal carbonate is K₂CO₃And Na₂CO₃At least one of them.

The first organic solvent is at least two of N-methyl pyrrolidone, N, N-dimethyl acetamide, N, N-dimethyl formamide, sulfolane, dimethyl sulfoxide and toluene.

The sulfhydryl-containing amino acid is DL-sulfhydryl butyl amino acid or N-acetyl cysteine, and the sulfhydryl-containing amino acid salt is DL-cysteine hydrochloride.

The second organic solvent is at least one of tetrahydrofuran, N, N-dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone, dimethyl sulfoxide and acetone.

In the step 3), 1-9g of polysulfone polymer is used.

The polysulfone polymer is polysulfone, sulfonated polysulfone, polyethersulfone, sulfonated polyethersulfone or double-bond polyethersulfone obtained in the step 1).

The third organic solvent is at least one of tetrahydrofuran, N, N-dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone, acetone and dimethyl sulfoxide.

The coagulating bath is water, and at least one of N, N-dimethylacetamide, dimethyl sulfoxide and N-methylpyrrolidone.

The chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is prepared by the method.

The invention has the advantages that:

the test result shows that the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane prepared by the invention has higher separation performance and excellent chlorine resistance. The method has the advantages of few reaction steps, simple preparation process and short reaction time.

Drawings

FIG. 1 shows the preparation of double-bond polyethersulfone (abbreviated as BPES) and amino acid-modified polyethersulfone (abbreviated as BPES-g-CYSAH) prepared in example 1 of the present invention¹H NMR spectrum.

FIG. 2 shows the water flux and salt rejection test results of the chlorine-resistant amino acid modified polyethersulfone reverse osmosis membrane prepared in example 1 and the membrane after chlorination.

Detailed Description

The present invention will be further illustrated by the following specific examples. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In each example DMPA is a shorthand for 2, 2-dimethoxy-2-phenylacetophenone.

Example 1

A preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane comprises the following steps:

1) synthesizing double-bond polyether sulfone:

6mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone (first monomer), 14mmol of 4,4 '-dihydroxydiphenyl sulfone (second monomer), 20mmol of 4,4' -difluorodiphenyl sulfone (third monomer), and,21mmol K₂CO₃Introducing nitrogen into 38mL of N-N dimethylacetamide and 20mL of toluene, heating to 140 ℃, reacting for 4h, removing water, heating to 170 ℃, reacting for 6h to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone (BPES).

The weight average molecular weight was determined to be 89,000 g/mol;

¹h NMR,. delta.8.14 (1H, a),. delta.7.85 (1H, c),. delta.6.50 (1H, b), see FIG. 1.

2) Synthesis of amino acid modified polyether sulfone:

stirring and dissolving 1g of double-bond polyether sulfone obtained in the step 1), 0.1g of DL-cysteine hydrochloride, 1g of DMPA and 10mL of N, N-dimethylformamide, introducing nitrogen, irradiating by using an ultraviolet light source with the wavelength of 365nm for 2 hours at the irradiation distance of 10cm, adding the irradiated solution into deionized water, precipitating and filtering to obtain a solid, washing by using the deionized water and ethanol in sequence, and drying in a vacuum oven at the temperature of 30 ℃ for 24 hours to obtain amino acid modified polyether sulfone (abbreviated as BPES-g-CYSAH); see fig. 1 (x in the formula of fig. 1 is the mole percentage of the first monomer to the sum of the moles of the first monomer and the moles of the second monomer).

¹H NMR,. delta.8.14 (1H, a),. delta.7.85 (1H, c),. delta.3.86 (1H, i),. delta.3.15 (2H, j), see FIG. 1.

3) Preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane:

dissolving 5g of the amino acid modified polyether sulfone prepared in the step 2) in 40mL of tetrahydrofuran to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate to scrape a membrane, volatilizing the membrane for 10s in the air, and immersing the membrane casting solution in a 25 ℃ water coagulation bath to form a membrane, thereby obtaining the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

The flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is measured to be 18L/m²h, the rejection of sodium chloride was 97.1%. After being soaked in 10000ppm sodium hypochlorite aqueous solution for 1h, 5h and 10h, the flux of the prepared chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is 19.1L/m respectively² h,19.5L/m²h and 21.6L/m²h, the retention rate is respectively 97.5 percent96.5% and 96%, see FIG. 2.

Example 2

A preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane comprises the following steps:

1) synthesizing double-bond polyether sulfone:

to a vessel were added 1mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone, 1mmol of 4,4 '-dihydroxydiphenyl sulfone, 2mmol of 4,4' -difluorodiphenyl sulfone, and 1mmol of Na₂CO₃Introducing nitrogen into 30mL of N-methylpyrrolidone and 20mL of toluene, heating to 110 ℃, reacting for 5h, removing water, heating to 200 ℃, reacting for 2h to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone;

2) synthesis of amino acid modified polyether sulfone:

stirring and dissolving 5g of double-bond polyether sulfone obtained in the step 1), 2g of DL-mercaptobutylamino acid, 0.5g of DMPA and 50mL of N, N-dimethylacetamide, introducing nitrogen, irradiating by using an ultraviolet light source with the wavelength of 365nm for 2 hours at the irradiation distance of 10cm, adding the irradiated solution into deionized water, precipitating, filtering to obtain a solid, washing by using the deionized water and ethanol in sequence, and drying in a vacuum oven at 50 ℃ for 24 hours to obtain amino acid modified polyether sulfone;

3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane: dissolving 1g of the amino acid modified polyether sulfone prepared in the step 2) and 10g of the double-bond polyether sulfone obtained in the step 1) in 100mL of acetone to prepare a membrane casting solution, standing and defoaming, pouring the membrane casting solution on a clean glass plate to scrape a membrane, volatilizing the membrane for 120s in the air, and immersing the membrane in a 0 ℃ water coagulation bath to form a membrane to obtain the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane;

the flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is measured to be 20.7L/m²h, the rejection of sodium chloride was 98.1%. After being soaked in 10000ppm sodium hypochlorite aqueous solution for 1h, 5h and 10h, the flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is 20.8L/m² h,21.1L/m²h and 22.3L/m²h, retention rates of 98%, 97% and 96.5%, respectively.

Example 3

A preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane comprises the following steps:

1) synthesizing double-bond polyether sulfone:

5mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone, 1mmol of 4,4 '-dihydroxydiphenyl sulfone, 6mmol of 4,4' -difluorodiphenyl sulfone and 1mmol of Na were added to a vessel₂CO₃And 12mmol K₂CO₃Introducing nitrogen into 50mL of dimethyl sulfoxide and 30mL of toluene, heating to 140 ℃, reacting at the temperature for 5 hours, removing water, heating to 180 ℃, reacting for 24 hours to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone;

2) synthesis of amino acid modified polyether sulfone:

dissolving 3g of double-bond polyether sulfone prepared in the step 1), 0.8g N-acetylcysteine, 1g of DMPA and 30mL of N-methylpyrrolidone, introducing nitrogen, irradiating by using an ultraviolet light source with the wavelength of 365nm, wherein the irradiation distance is 10cm, the irradiation time is 2 hours, adding the irradiated solution into deionized water, precipitating, filtering to obtain a solid, washing by using the deionized water and ethanol in sequence, and drying in a vacuum oven at the temperature of 30 ℃ for 48 hours to obtain amino acid modified polyether sulfone;

3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane:

dissolving 3g of the amino acid modified polyether sulfone prepared in the step 2) and 9g of polysulfone with the weight-average molecular weight of 600,000g/mol in 60mL of N, N-dimethylacetamide to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate for membrane scraping, volatilizing the membrane in air for 30s, and immersing the membrane casting solution in an N, N-dimethylacetamide aqueous solution with the volume concentration of 5% at 30 ℃ as a coagulating bath to form a membrane, thereby obtaining the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

The flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is measured to be 21.2L/m²h, the rejection of sodium chloride was 97.1%. After being soaked in 10000ppm sodium hypochlorite solution for 1h, 5h and 10h, the flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is 22.3L/m² h,23.5L/m²h and 23.5L/m²h, retention rate respectively97%, 97% and 96.4%.

Example 4

A preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane comprises the following steps:

1) synthesizing double-bond polyether sulfone:

to a vessel were added 10mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone, 1mmol of 4,4 '-dihydroxydiphenyl sulfone, 11mmol of 4,4' -difluorodiphenyl sulfone, and 10mmol of Na₂CO₃And 2mmol K₂CO₃Introducing nitrogen into 60mL of sulfolane and 40mL of toluene, heating to 140 ℃, reacting for 3h, removing water, heating to 190 ℃, reacting for 10h to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone; the weight average molecular weight is g/mol;

2) synthesis of amino acid modified polyether sulfone:

dissolving 5g of the double-bond polyether sulfone prepared in the step 1), 2g of DL-cysteine hydrochloride, 0.1g of DMPA and 10mL of acetone, introducing nitrogen, irradiating by using an ultraviolet light source with the wavelength of 365nm, wherein the irradiation distance is 10cm, the irradiation time is 2 hours, adding the irradiated solution into deionized water, precipitating, filtering to obtain a solid, washing by using the deionized water and ethanol in sequence, and drying in a vacuum oven at 50 ℃ for 36 hours to obtain amino acid modified polyether sulfone;

3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane:

dissolving 5g of the amino acid modified polyether sulfone prepared in the step 2) and 10g of sulfonated polysulfone with the weight-average molecular weight of 20,000g/mol in 100mL of N-methylpyrrolidone to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate for membrane scraping, immersing the membrane casting solution in a mixture of the N-methylpyrrolidone and water with the volume fraction of 5 percent at 10 ℃ for membrane forming, and obtaining the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane

The flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is measured to be 15.8L/m²h, the rejection of sodium chloride was 96.1%. After being soaked in 10000ppm sodium hypochlorite aqueous solution for 1h, 5h and 10h, the flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is 15.8L/m² h,16.7L/m²h and 17.9L/m²h, retention rates of 96%, 95.8% and 95.4%, respectively.

Example 5

A preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane comprises the following steps:

1) synthesizing double-bond polyether sulfone:

adding 10mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone, 10mmol of 4,4 '-dihydroxydiphenyl sulfone, 20mmol of 4,4' -difluorodiphenyl sulfone and 10mmol of Na into a container₂CO₃And 5mmol K₂CO₃Introducing nitrogen into 50mL of N-methylpyrrolidone and 40mL of toluene, heating to 130 ℃, reacting for 3h, removing water, heating to 170 ℃, reacting for 12h to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone IV-5;

2) synthesis of amino acid modified polyether sulfone:

dissolving 1g of double-bond polyether sulfone prepared in the step 1), 0.1g N-acetylcysteine, 0.5g of DMPA and 30mL of tetrahydrofuran, introducing nitrogen, irradiating by using an ultraviolet light source with the wavelength of 365nm, wherein the irradiation distance is 10cm, the irradiation time is 2 hours, adding the irradiated solution into deionized water, precipitating and filtering to obtain a solid, washing by using the deionized water and ethanol in sequence, and drying in a vacuum oven at 40 ℃ for 24 hours to obtain amino acid modified polyether sulfone;

3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane:

dissolving 3g of the amino acid modified polyether sulfone prepared in the step 2) and 7g of polyether sulfone with the weight-average molecular weight of 100,000g/mol in 100mL of dimethyl sulfoxide to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate for scraping the membrane, volatilizing the membrane in the air for 20s, and immersing the membrane casting solution in a solidification bath of a mixture of 10% by volume of dimethyl sulfoxide and water at 25 ℃ to form a membrane, thereby obtaining the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

The flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is measured to be 12.3L/m²h, the rejection of sodium chloride was 97.1%. After soaking in 10000ppm sodium hypochlorite aqueous solution for 1h, 5h and 10h, the product is resistant toThe flux of the chloroamino acid modified polyether sulfone reverse osmosis membrane is respectively 13.8L/m² h,14.1L/m²h and 15.6L/m²h, the retention rates were 97%, 96.8% and 96.4%, respectively.

Example 6

A preparation method of a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane comprises the following steps:

1) synthesizing double-bond polyether sulfone:

5mmol of 3,3 '-diallyl-4, 4' -dihydroxydiphenyl sulfone, 1mmol of 4,4 '-dihydroxydiphenyl sulfone, 6mmol of 4,4' -difluorodiphenyl sulfone and 30mmol of K were added to a vessel₂CO₃Introducing nitrogen into 80mL of N, N-dimethylformamide and 20mL of toluene, heating to 150 ℃, reacting for 2 hours, removing water, heating to 180 ℃, reacting for 5 hours to obtain a viscous solution, precipitating and washing in deionized water, washing with ethanol, and drying in vacuum to obtain double-bond polyether sulfone;

2) synthesis of amino acid modified polyether sulfone:

dissolving 5g of the double-bond polyether sulfone prepared in the step 1), 2g of DL-mercaptobutylamino acid, 1g of DMPA and 50mL of dimethyl sulfoxide, introducing nitrogen, irradiating by using an ultraviolet light source with the wavelength of 365nm, wherein the irradiation distance is 10cm, the irradiation time is 2 hours, adding the irradiated solution into deionized water, precipitating, filtering to obtain a solid, washing by using the deionized water and ethanol in sequence, and drying in a vacuum oven at the temperature of 30 ℃ for 24 hours to obtain amino acid modified polyether sulfone;

3) preparing a chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane:

dissolving 5g of the amino acid modified polyether sulfone prepared in the step 2) and 1g of sulfonated polyether sulfone with the weight-average molecular weight of 60,000g/mol in 60mL of N, N-dimethylformamide to prepare a membrane casting solution, standing for defoaming, pouring the membrane casting solution on a clean glass plate for scraping the membrane, volatilizing the membrane in the air for 120s, and immersing the membrane in a water coagulation bath at 40 ℃ for membrane formation to obtain the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane.

The flux of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane is measured to be 14.9L/m²h, the rejection of sodium chloride was 97.1%. Soaking in 10000ppm sodium hypochlorite water solution for 1 hr, 5 hr and 10 hr to obtain chlorine-resistant amino acidThe flux of the modified polyether sulfone reverse osmosis membrane is respectively 15.8L/m² h,16.3L/m²h and 17.9L/m²h, retention rates of 96.6%, 95.8% and 95.5%, respectively.

Film Performance testing

Evaluation of separation Performance

The water flux and the salt rejection rate are two important parameters for evaluating the separation performance of the reverse osmosis membrane, and the separation performance of the reverse osmosis membrane is evaluated by cross flow permeation filtration equipment.

The performance test of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane adopts the following test conditions: the water flux and salt rejection rate of the membrane were tested using 2000ppm NaCl aqueous solution as feed solution, operating pressure of 1.55MPa, temperature of 25 deg.C, and stabilization time of 30 min.

(1) Water flux (J) is defined as: the volume of water per membrane area per unit time is expressed in L/m under certain operating conditions²h, the formula is as follows:

wherein V (L) is the permeation volume of water; a (m)²) Is the effective area of the membrane; t (h) is the permeation time.

(2) The salt rejection (R) is defined as: under certain operating conditions, the concentration difference of the feed liquid and the permeate liquid accounts for the percentage of the concentration of the feed liquid, and the unit of the concentration difference is as follows;

wherein C is_pIs the concentration of the permeate, C_fIs the concentration of the feed solution.

1. Chlorine resistance test

Preparing aqueous solution with sodium hypochlorite concentration of 10000ppm, adjusting pH to 7 with 0.1mol/L HCl, soaking the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane in the aqueous solution of sodium hypochlorite for 1h, 5h and 10h, performing chlorine resistance experiment, and testing the flux and salt rejection rate of the membrane after soaking (the test conditions are the same as above)

Through the test:

table 1 lists the water flux and salt rejection and chlorine resistance test data for the chlorine resistant amino acid modified polyethersulfone reverse osmosis membranes prepared in examples 1-6. The result shows that the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membrane prepared by the invention has higher water flux, salt rejection rate and chlorine resistance.

Table 1 shows the water flux and salt rejection and chlorine resistance test data of the chlorine-resistant amino acid modified polyether sulfone reverse osmosis membranes prepared in examples 1 to 6

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.