CN115569536B - Anti-pollution ultrafiltration membrane and preparation method and application thereof - Google Patents

Abstract

The invention discloses an anti-pollution ultrafiltration membrane and its preparation method and application, belonging to the technical field of membrane separation. The preparation method of the anti-pollution ultrafiltration membrane comprises: (1) amination modification of polymer powder to obtain amination Modified polymer powder; (2) Utilize aminated modified polymer powder to prepare casting liquid, cast film casting liquid on support layer to form film again, then transfer to coagulation bath to solidify and form to obtain wet film, further wash and dry Obtain amino-containing ultrafiltration membrane after drying; (3) take epoxy monomer, zwitterionic monomer and initiator as raw material generation polymerization to prepare epoxy-zwitterionic copolymer; (4) pass through epoxy ring-opening reaction, will Epoxy-zwitterionic copolymer is grafted onto the amino-containing ultrafiltration membrane of step (2) to obtain the anti-pollution ultrafiltration membrane. The anti-pollution ultrafiltration membrane prepared by the method of the invention has good hydrophilicity, has excellent anti-protein pollution ability and anti-bacterial adhesion ability, and can maintain relatively high flux of pure water.

Description

A kind of anti-fouling ultrafiltration membrane and its preparation method and application

technical field

The invention belongs to the technical field of membrane separation, and in particular relates to an anti-pollution ultrafiltration membrane and its preparation method and application.

Background technique

Membrane separation technology can effectively intercept pollutants, bacteria and pathogenic bacteria. It has the advantages of high efficiency, energy saving, environmental protection, simple filtration process and easy control. It has become one of the most promising technologies in the fields of water treatment and hemodialysis. Membranes can be divided into microfiltration membranes, ultrafiltration membranes, nanofiltration membranes, reverse osmosis membranes, etc. from the application process. The minimum molecular weight cut-off of ultrafiltration membranes is 2000 Daltons, which can be used to separate proteins, enzymes, nucleic acids, polysaccharides, and peptides. , antibiotics, viruses, etc. There is no phase transfer during the use of the ultrafiltration membrane, and there is no need to add any toxic and harmful chemicals, so it is widely used.

During the use of ultrafiltration membranes, the deposition or adsorption of various pollutants will lead to a serious decrease in membrane flux and increase the application cost. Therefore, improving the anti-pollution ability of ultrafiltration membranes is one of the problems that need to be solved urgently in the prior art . Divided from the sources of pollutants, membrane fouling mainly includes inorganic pollution, organic pollution and biological pollution. Among them, biofouling is a common problem faced by ultrafiltration membranes in the fields of water treatment and hemodialysis, and inhibiting protein contamination and bacterial adhesion is an important way to control biofouling. In order to solve the above-mentioned pollution problems in the process of using ultrafiltration membranes, commonly used methods mainly include raw material treatment, optimization of membrane separation process, membrane cleaning, and development of anti-fouling membranes, among which the first three methods need to introduce other operations and increase costs. , and membrane fouling cannot be eradicated, the development of anti-fouling membranes to inhibit the interaction between pollution sources and membrane materials is the fundamental method to solve membrane fouling.

The Chinese patent document with publication number CN112316754A discloses a preparation method of an anti-pollution hollow fiber ultrafiltration membrane: using a blending method, adding magnetic nanoparticles to the casting liquid, and then spinning to prepare an anti-pollution hollow fiber ultrafiltration membrane , wherein the weight percentage content of magnetic nanoparticles in the casting solution is 0.1%-5%; the hollow fiber ultrafiltration membrane prepared by this method is magnetic and can swing under the action of a magnetic field, which is beneficial to remove pollutants from the membrane filaments The surface and hollow interior are cleaned out, but the magnetic nanoparticles blended in this method have the risk of falling off during the preparation and use of the membrane, which may cause secondary pollution and are not suitable for long-term use.

The Chinese patent literature with the publication number CN108579438A discloses a method for preparing a large-flux anti-pollution polyvinyl chloride ultrafiltration membrane. In this method, the polymer is mixed with an organic solvent, and the polymer is first heated and activated under the protection of nitrogen, and then an amphiphilic intercalation membrane is added. Continue to stir the block copolymer to completely dissolve the polymer and the amphiphilic block copolymer, and finally let it stand for defoaming to obtain the casting solution; dissolve the inorganic salt in deionized water to obtain a coagulation bath; pour the casting solution on the glass On the plate, scrape it flat with a scraper, immerse the glass plate with the casting solution in the coagulation bath, take it out after gelation, and obtain a large-flux anti-pollution polyvinyl chloride ultrafiltration membrane. In this method, the anti-pollution substance is introduced through the stirring process, and the anti-pollution substance is easily wrapped during the membrane forming process, reducing the anti-pollution efficiency.

Contents of the invention

The invention provides a method for preparing an anti-pollution ultrafiltration membrane. The method has simple process, low equipment requirements and mild reaction conditions. The prepared anti-pollution ultrafiltration membrane has good hydrophilicity, and has excellent anti-protein pollution ability and Anti-bacterial adhesion ability, able to maintain high pure water flux.

The specific technical scheme adopted is as follows:

A preparation method of an anti-pollution ultrafiltration membrane, comprising the following steps:

(1) carry out amination modification to polymer powder to obtain amination modified polymer powder;

(2) Utilize the amination-modified polymer powder in step (1) to prepare the casting solution, then cast the casting solution on the support layer to form a film, then transfer it to the coagulation bath to solidify and form a wet film, wash and dry Obtain an amino-containing ultrafiltration membrane;

(3) take epoxy monomer, zwitterionic monomer and initiator as raw material generation polymerization reaction to prepare epoxy-zwitterionic copolymer;

(4) Grafting the epoxy-zwitterionic copolymer to the amino group-containing ultrafiltration membrane in step (2) through an epoxy ring-opening reaction to obtain the anti-pollution ultrafiltration membrane.

In the present invention, the polymer powder is aminated, and the amino group-containing ultrafiltration membrane is prepared by phase inversion of the aminated polymer solution; then, the amino group on the amino group-containing ultrafiltration membrane undergoes an epoxy ring-opening reaction with the epoxy-zwitterionic copolymer, thereby The anti-fouling ultrafiltration membrane is prepared by grafting zwitterionic polymers on the amino-containing ultrafiltration membrane; the epoxy-zwitterionic copolymer and the amino-containing ultrafiltration membrane are connected by covalent bonds, and the binding force is strong, and the grafted amphoteric Ionic polymers have both positive and negative groups, which can easily form a hydration layer and have strong hydration, so they have the ability to resist protein pollution. The method of the invention has low equipment requirements, simple preparation method, and is convenient to improve on the basis of the traditional ultrafiltration membrane preparation process to realize enlarged production. The obtained anti-pollution ultrafiltration membrane has good hydrophilicity, and has excellent anti-protein pollution performance, and can It maintains high pure water flux, has good anti-bacterial adhesion ability, and has broad prospects in the fields of water treatment and hemodialysis.

The polymer powder includes polysulfone, polyethersulfone, polyacrylonitrile, polyvinylidene fluoride, polyvinyl chloride or polyimide and the like.

Preferably, in step (1), the polymer powder is placed in an amino monomer aqueous solution for amination modification; the amino monomer is ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine , tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine at least one.

Further preferably, the concentration of the amino monomer aqueous solution is 5-20 wt %; the temperature of the amination modification is 80-180° C., and the time is 20-70 h.

The invention carries out amination modification on the polymer powder, and then utilizes the amination modification polymer powder to form a membrane, the degree of amination modification is high, and the parameters such as membrane thickness and pore diameter are easy to adjust, and the membrane production parameters can be adjusted according to the needs of the product. .

Preferably, in step (2), the casting solution is an amination-modified polymer powder solution with a concentration of 15-25 wt%, and the solvent is selected from acetone, N,N-dimethylformamide, tetrahydrofuran, N,N-di At least one of methylacetamide and N-methylpyrrolidone;

Preferably, in step (2), the coagulation bath is water, methanol or ethanol, and the temperature of the coagulation bath is 20-50°C.

Synthesis and grafting of epoxy-zwitterionic copolymers are the key to the preparation of the anti-pollution ultrafiltration membrane. In step (3), the epoxy monomers are glycidyl methacrylate, 4-hydroxybutyl acrylate At least one of glycidyl ether and allyl glycidyl ether; the zwitterionic monomer is [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide , at least one of 3-[[2-(methacryloyloxy)ethyl]dimethylammonium] propionate and 2-methacryloyloxyethyl phosphorylcholine, and the initiator is even At least one of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptanonitrile and dibenzoyl peroxide.

Preferably, in the polymerization reaction system, the molar ratio of the epoxy monomer to the zwitterionic monomer is 1:9-9:1, and the amount of the initiator is 1-8 mol% of the total amount of the epoxy monomer and the zwitterionic monomer.

The polymerization reaction time is 3-10 hours, and the temperature is 50-90°C.

Specifically, in step (3), the epoxy monomer, the zwitterionic monomer and the initiator are mixed, and reacted for 3-10 hours under the condition of heating and stirring at 50-90° C. to obtain a crude product solution, and the crude product solution is dropped into A precipitate is obtained in absolute ethanol, and the precipitate is dissolved in water and freeze-dried to obtain the epoxy-zwitterionic copolymer.

The structural formula of described epoxy-zwitterionic copolymer is represented as:

Wherein, R ₁ is the zwitterionic monomer residue, R ₂ is the epoxy monomer residue, and both m and n are positive integers of 1-100.

Preferably, the number average molecular weight of the epoxy-zwitterionic copolymer is 20000-30000.

Preferably, in step (4), the specific steps of the epoxy ring-opening reaction are: placing the amino group-containing ultrafiltration membrane in an epoxy-zwitterionic copolymer solution for grafting reaction, and the grafting reaction temperature is 50-90°C , The grafting reaction time is 6-24h.

Further preferably, the concentration of the epoxy-zwitterionic copolymer solution is 5-30 mg/mL; the product film prepared within the above preferred concentration range has excellent hydrophilicity.

The catalysts for the epoxy ring-opening reaction are triethylamine solution, dodecyl trimethyl ammonium chloride solution, dodecyl dimethyl benzyl ammonium chloride solution, dodecyl dimethyl benzyl bromide One of ammonium solution, pyridine solution, potassium hydroxide solution or sodium hydroxide solution.

The present invention also provides the anti-pollution ultrafiltration membrane prepared by the preparation method of the anti-pollution ultrafiltration membrane; the anti-pollution ultrafiltration membrane comprises an amino-containing ultrafiltration membrane and epoxy resin grafted on the amino-containing ultrafiltration membrane - zwitterionic copolymers.

The invention also provides the application of the anti-pollution ultrafiltration membrane in the technical field of membrane separation. The anti-pollution ultrafiltration membrane has excellent anti-protein pollution ability and anti-bacterial adhesion ability, can maintain high pure water flux, and can be applied to aspects such as water treatment or hemodialysis.

Compared with prior art, the beneficial effect of the present invention is:

(1) In the present invention, under the action of an initiator, epoxy monomers and zwitterionic monomers are free radically polymerized to synthesize epoxy-zwitterionic copolymers, and then anchored on amino-containing ultrafiltration membranes through epoxy ring-opening reactions Fixed zwitterionic, epoxy-zwitterionic copolymer and amino-containing ultrafiltration membrane are connected by covalent bonds, with strong binding force, and the modified layer constructed is more stable than non-covalent modification methods such as surface coating and blending doping , to avoid the risk of the modified layer falling off during long-term use.

(2) In the present invention, the amino-containing ultrafiltration membrane is prepared by amination modified polymer powder, the raw polymer powder is modified, and the phase inversion method is optimized to prepare the whole process of the ultrafiltration membrane, so that the grafted sites of the anti-pollution medium Uniform distribution of dots, easy anti-pollution modification and good modification effect, easy to control the properties and structure of the ultrafiltration membrane.

(3) The present invention grafts the epoxy-zwitterionic copolymer onto the amino-containing ultrafiltration membrane, and the prepared anti-pollution ultrafiltration membrane has good anti-protein pollution ability and anti-bacterial adhesion ability, good hydrophilicity, and water The contact angle reaches as low as 33°, which can maintain a high pure water flux.

(4) The preparation method of the anti-pollution ultrafiltration membrane provided by the present invention is simple and has low equipment requirements, is easy to store and has a long service life, low preparation cost, no toxic and harmful substance residue, and is convenient for large-scale preparation and production. It is used in the fields of water treatment and hemodialysis Has broad prospects.

Description of drawings

Fig. 1 is the XPS analysis result figure of the anti-pollution ultrafiltration membrane in embodiment 3 and the amino-containing ultrafiltration membrane in comparative example 1, wherein, A is the amino-containing polyethersulfone membrane of comparative example 1, and B is embodiment 3 antifouling polyethersulfone membrane.

FIG. 2 is a comparison chart of water contact angles between the anti-fouling ultrafiltration membrane in Example 3 and the amino group-containing ultrafiltration membrane in Comparative Example 1. FIG.

Fig. 3 is the flux-time variation graph of filtering 1 g/L bovine serum albumin solution by the anti-pollution ultrafiltration membrane in Example 3 and the amino group-containing ultrafiltration membrane in Comparative Example 1.

Fig. 4 is the Escherichia coli adhesion scanning electron micrograph of the anti-pollution ultrafiltration membrane in Example 3 and the amino-containing ultrafiltration membrane in Comparative Example 1, wherein, A is the amino-containing polyethersulfone membrane of Comparative Example 1, and B is the implementation Anti-fouling polyethersulfone membrane of Example 3.

Detailed ways

Below in conjunction with embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention, not to limit the scope of the present invention.

Zwitterionic monomers 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propionate (CAS No.: 24249-95-4), 2-methacryloyloxyethylphosphonate Acylcholine (CAS:67881-98-5), [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (CAS:3637-26-1 ) were purchased from Shanghai Yuanye Biotechnology Co., Ltd.

Example 1

(1) Put the polysulfone powder in a 5wt% aqueous solution of ethylenediamine and heat-treat it at 80°C for 70 hours. After the amination reaction, take out the powder, wash it with absolute ethanol and ultrapure water three times in turn, and dry it naturally to obtain the amination Modified polysulfone powder;

(2) Place the amination-modified polysulfone powder in acetone and stir to dissolve it to obtain a casting solution with a concentration of 15 wt%. layer, and then quickly transferred to 20°C ultrapure water to solidify and form a wet membrane, which was soaked in ultrapure water for cleaning and then dried naturally to obtain an amino-containing polysulfone ultrafiltration membrane;

(3) Preparation of a mixed solution of 4-hydroxybutyl acrylate glycidyl ether and [2-(methacryloyloxy) ethyl] dimethyl-(3-sulfonic acid propyl) ammonium hydroxide (4- Hydroxybutyl acrylate glycidyl ether content is 10mol%), after stirring evenly, nitrogen is purged, then adds the azobisisobutyronitrile of epoxy monomer and zwitterionic monomer total amount 1mol%, then reaction system is placed in In a three-neck flask, react at 50°C for 10 hours. After the reaction, drop the crude product solution into absolute ethanol to obtain a precipitate. The precipitate is dissolved in water and freeze-dried to obtain a white solid powder of epoxy-zwitterionic copolymer. Oxygen-zwitterionic copolymer is poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-co-4-hydroxybutyl acrylate glycidyl ether);

(4) Place the amino-containing polysulfone ultrafiltration membrane in 5 mg/mL poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide-co -4-hydroxybutyl acrylate glycidyl ether) solution, followed by poly([2-(methacryloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide per ml -co-4-hydroxybutyl acrylate glycidyl ether) solution was added to 100 μL pyridine solution, and reacted at 50°C for 24 hours. After the reaction, the membrane was taken out, rinsed with ultrapure water three times, and dried naturally to obtain anti-pollution polysulfone ultrafiltration membrane.

Example 2

(1) Put the polyethersulfone powder in an 8wt% hexamethylenediamine aqueous solution and heat-treat it at 100°C for 60 hours. After the amination reaction, take out the powder, wash it three times with absolute ethanol and ultrapure water, and dry naturally to obtain amino Chemically modified polyethersulfone powder;

(2) Place the aminated modified polyethersulfone powder in N,N-dimethylformamide and stir to dissolve to obtain a casting solution with a concentration of 17wt%. After standing for defoaming, cast the casting solution with a scraper Scratch coating on the support layer of polypropylene non-woven fabric, and then quickly transferred to 25 ℃ ultra-pure water to solidify and form a wet film. The wet film was soaked in ultra-pure water and then dried naturally to obtain amino-containing polyethersulfone ultrafiltration membrane;

(3) Prepare a mixed solution of glycidyl methacrylate and 3-[[2-(methacryloyloxy) ethyl] dimethyl ammonium] propionate (glycidyl methacrylate content is 10mol%) , after stirring evenly, purging with nitrogen, then adding azobisisovaleronitrile of 3 mol% of the total amount of epoxy monomer and zwitterionic monomer, then placing the reaction system in a three-necked flask, and reacting at 70°C for 4h, the reaction After the end, the crude product solution is dropped into absolute ethanol to obtain a precipitate, and the precipitate is dissolved in water and freeze-dried to obtain a white solid powder of epoxy-zwitterionic copolymer, which is poly(3-[[ 2-(methacryloyloxy)ethyl]dimethylammonium]propionate-co-glycidyl methacrylate);

(4) Put the amino-containing polyethersulfone ultrafiltration membrane in 7mg/mL poly(3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propionate-co-methacrylic acid glycidyl ester) solution, followed by adding 100 μL ten The dialkyltrimethylammonium chloride solution was reacted at 50°C for 6 hours. After the reaction, the diaphragm was taken out, rinsed three times with ultrapure water, and dried naturally to obtain an anti-pollution polyethersulfone ultrafiltration membrane.

Example 3

(1) Put the polyethersulfone powder in a 10wt% diethylenetriamine aqueous solution and heat-treat it at 80°C for 70 hours. After the amination reaction, take out the powder, wash it three times with absolute ethanol and ultrapure water, and dry it naturally to obtain Aminated modified polyethersulfone powder;

(2) Put the amination-modified polyethersulfone powder in N,N-dimethylformamide and stir to dissolve it to obtain a casting solution with a concentration of 20wt%, and cast the casting solution with a scraper after standing for defoaming Scratch coating on the support layer of polypropylene non-woven fabric, and then quickly transferred to 50 ℃ ultra-pure water to solidify and form a wet film. The wet film was soaked in ultra-pure water and then dried naturally to obtain amino-containing polyethersulfone ultrafiltration membrane;

(3) Prepare a mixed solution of glycidyl methacrylate and [2-(methacryloxy)ethyl]dimethyl-(3-sulfonic acid propyl) ammonium hydroxide (glycidyl methacrylate content is 20mol%), nitrogen purging after stirring evenly, then add azobisisobutyronitrile with 1mol% of the total amount of epoxy monomer and zwitterionic monomer, then place the reaction system in a three-necked flask, and react at 70°C Under the condition of reaction for 6h, after the reaction, the crude product solution was dropped into absolute ethanol to obtain a precipitate, and the precipitate was dissolved in water and freeze-dried to obtain a white solid powder of epoxy-zwitterionic copolymer. The epoxy-zwitterionic copolymer is Poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide-co-glycidyl methacrylate), the structural formula is shown in the following formula, wherein, x and y are positive integers of 1-100.

(4) Put the amino-containing polyethersulfone ultrafiltration membrane in 30mg/mL poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide-co -glycidyl methacrylate) solution, followed by poly([2-(methacryloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-co-methanol Glycidyl acrylate) solution was added to 100 μL triethylamine solution, and reacted at 60°C for 12 hours. After the reaction, the membrane was taken out, washed three times with ultrapure water, and dried naturally to obtain an anti-pollution polyethersulfone ultrafiltration membrane.

Example 4

(1) Place the polyacrylonitrile powder in 20wt% triethylenetetramine aqueous solution for heat treatment at 180°C for 30h, take out the powder after the amination reaction is completed, wash with absolute ethanol and ultrapure water three times in turn, and dry naturally to obtain Aminated modified polyacrylonitrile powder;

(2) Place the amination-modified polyacrylonitrile powder in tetrahydrofuran and stir and dissolve it to obtain a casting solution with a concentration of 25 wt%. on the support layer, and then quickly transferred to methanol at 40°C for solidification and forming to obtain a wet membrane. The wet membrane was soaked in ultrapure water for cleaning and then dried naturally to obtain an amino-containing polyacrylonitrile ultrafiltration membrane;

(3) Preparation of a mixed solution of allyl glycidyl ether and 3-[[2-(methacryloyloxy)ethyl]dimethylammonium] propionate (the content of allyl glycidyl ether is 30mol%) , after stirring evenly, purging with nitrogen, then adding dibenzoyl peroxide with 3mol% of the total amount of epoxy monomer and zwitterionic monomer, then placing the reaction system in a three-necked flask, and reacting for 6h under the reaction conditions of 80°C, After the reaction is finished, the crude product solution is dropped into absolute ethanol to obtain a precipitate, which is dissolved in water and freeze-dried to obtain a white solid powder of epoxy-zwitterionic copolymer, which is poly(3-[ [2-(methacryloyloxy)ethyl]dimethylammonium]propionate-co-allyl glycidyl ether);

(4) Place the amino-containing polyacrylonitrile ultrafiltration membrane in 20mg/mL poly(3-[[2-(methacryloyloxy)ethyl]dimethylammonium] propionate-co-allyl alcohol shrink Glyceryl ether) solution, followed by adding 100 μL of hydroxide per mL of poly(3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propionate-co-allyl glycidyl ether) solution The sodium solution was reacted at 80°C for 20 hours. After the reaction, the membrane was taken out, rinsed three times with ultrapure water, and dried naturally to obtain an anti-pollution polyacrylonitrile ultrafiltration membrane.

Example 5

(1) Put the polyvinylidene fluoride powder in a 15wt% tetraethylenepentamine aqueous solution and heat-treat it at 100°C for 50 hours. After the amination reaction, take out the powder, wash it three times with absolute ethanol and ultrapure water, and dry it naturally Obtain aminated modified polyvinylidene fluoride powder;

(2) Place the aminated modified polyvinylidene fluoride powder in N,N-dimethylacetamide and stir to dissolve to obtain a casting solution with a concentration of 18wt%, and cast the casting solution with a scraper after standing for defoaming Scrape-coated on the polypropylene non-woven support layer, and then quickly transferred to 40 ℃ methanol to solidify and form a wet film. The wet film was soaked in ultrapure water and cleaned, and then dried naturally to obtain an amino-containing polyvinylidene fluoride ultrafiltration membrane. ;

(3) Prepare a mixed solution of glycidyl methacrylate and [2-(methacryloxy)ethyl]dimethyl-(3-sulfonic acid propyl) ammonium hydroxide (glycidyl methacrylate content is 40mol%), nitrogen purging after stirring evenly, then add the azobisisoheptanonitrile of 3mol% of the total amount of epoxy monomer and zwitterionic monomer, then place the reaction system in a three-necked flask, and react at 90°C Under the condition of reaction for 6h, after the reaction, the crude product solution was dropped into absolute ethanol to obtain a precipitate, and the precipitate was dissolved in water and freeze-dried to obtain a white solid powder of epoxy-zwitterionic copolymer. The epoxy-zwitterionic copolymer is Poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-co-glycidyl methacrylate);

(4) Put the amino-containing polyvinylidene fluoride ultrafiltration membrane in 20mg/mL poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide- co-allyl glycidyl ether) solution, followed by poly([2-(methacryloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-co- Allyl alcohol glycidyl ether) solution was added to 100 μL ammonium bromide solution, and reacted at 60°C for 24 hours. After the reaction, the membrane was taken out, rinsed with ultrapure water three times, and dried naturally to obtain an anti-pollution polyvinylidene fluoride ultrafiltration membrane. .

Example 6

(1) Put the polyvinyl chloride powder in a 12wt% tetraethylenepentamine aqueous solution at 90°C for heat treatment for 24 hours, take out the powder after the amination reaction is completed, wash with absolute ethanol and ultrapure water three times in turn, and dry naturally to obtain Aminated modified polyvinyl chloride powder;

(2) Amination modified polyvinyl chloride powder is placed in N-methylpyrrolidone and stirred and dissolved to obtain a casting solution with a concentration of 15 wt%. Propylene non-woven support layer, and then quickly transferred to 30 ℃ ethanol to solidify and form a wet film, the wet film was soaked in ultrapure water and cleaned, and then dried naturally to obtain an amino-containing polyvinyl chloride ultrafiltration membrane;

(3) Preparation of a mixed solution of allyl glycidyl ether and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl) ammonium hydroxide (allyl glycidyl ether content is 60mol%), nitrogen purging after stirring evenly, then add the azobisisovaleronitrile of 8mol% of the total amount of epoxy monomer and zwitterionic monomer, then place the reaction system in a three-necked flask, and react at 80°C Under the condition of reaction for 6h, after the reaction, the crude product solution was dropped into absolute ethanol to obtain a precipitate, and the precipitate was dissolved in water and freeze-dried to obtain a white solid powder of epoxy-zwitterionic copolymer. The epoxy-zwitterionic copolymer is Poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide-co-allyl glycidyl ether) white solid powder;

(4) Put the amino-containing polyvinyl chloride ultrafiltration membrane in 25 mg/mL poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide- co-allyl glycidyl ether) solution, followed by poly([2-(methacryloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-co- Allyl alcohol glycidyl ether) solution was added to 100 μL dodecyltrimethylammonium chloride solution, and reacted at 90°C for 10 hours. After the reaction, the diaphragm was taken out, rinsed three times with ultrapure water, and dried naturally to obtain anti-pollution PVC ultrafiltration membrane.

Example 7

(1) Put the polyimide powder in a 5wt% polyethyleneimine aqueous solution and heat-treat it at 80°C for 48 hours. After the amination reaction, take out the powder, wash it three times with absolute ethanol and ultrapure water, and dry it naturally to obtain Amination modified polyimide powder;

(2) Amination modified polyimide powder is placed in N-methylpyrrolidone and stirred and dissolved to obtain a casting solution with a concentration of 10wt%. After standing for defoaming, cast the casting solution on On the polypropylene non-woven support layer, and then quickly transferred to 50 ℃ ultrapure water to solidify and form a wet film, the wet film was soaked in ultrapure water and cleaned, and then dried naturally to obtain an amino-containing polyimide ultrafiltration membrane;

(3) Prepare a mixed solution of 4-hydroxybutyl acrylate glycidyl ether and 2-methacryloyloxyethyl phosphorylcholine (4-hydroxybutyl acrylate glycidyl ether content is 70mol%), stir After uniformity, purging with nitrogen, then adding azobisisoheptanonitrile with a total amount of 7 mol% of epoxy monomer and zwitterionic monomer, and then placing the reaction system in a three-necked flask, reacting at 90°C for 10 hours, and the reaction is over Finally, the crude product solution is dropped into absolute ethanol to obtain a precipitate, which is dissolved in water and freeze-dried to obtain a solid powder of epoxy-zwitterionic copolymer, which is poly(2-methacryloyl Oxyethylphosphorylcholine-co-4-hydroxybutylacrylate glycidyl ether);

(4) Place the amino-containing polyimide ultrafiltration membrane in 30 mg/mL poly(2-methacryloyloxyethyl phosphorylcholine-co-4-hydroxybutyl acrylate glycidyl ether) solution , followed by adding 100 μL of pyridine solution per milliliter of poly(2-methacryloyloxyethylphosphorylcholine-co-4-hydroxybutyl acrylate glycidyl ether) solution, and reacting at 50°C for 24 hours, After the reaction, the membrane was taken out, rinsed three times with ultrapure water, and dried naturally to obtain an anti-pollution polyimide ultrafiltration membrane.

Example 8

(1) Put the polyethersulfone powder in a 20wt% diethylenetriamine aqueous solution and heat-treat it at 170°C for 20 hours. After the amination reaction, take out the powder, wash it with absolute ethanol and ultrapure water three times in turn, and dry it naturally to obtain the amino group. Chemically modified polyethersulfone powder;

(2) Place the amination-modified polyethersulfone powder in acetone and stir to dissolve to obtain a casting solution with a concentration of 25 wt%. on the support layer, and then quickly transferred to 30°C ultra-pure water to solidify and form a wet membrane, which was soaked in ultra-pure water for cleaning and then dried naturally to obtain an amino-containing polyethersulfone ultrafiltration membrane;

(3) Prepare a mixed solution of glycidyl methacrylate and 2-methacryloyloxyethyl phosphorylcholine (the content of glycidyl methacrylate is 90mol%), stir it evenly and then blow it with nitrogen, then add Epoxy monomer and the dibenzoyl peroxide of zwitterionic monomer total amount 3mol%, then reaction system is placed in there-necked flask, reacts 3h under 90 ℃ of reaction conditions, after reaction finishes, crude product solution is dripped into Obtain precipitation in water ethanol, precipitate is dissolved in water and obtains epoxy-zwitterionic copolymer white solid powder through freeze-drying, and this epoxy-zwitterionic copolymer is poly(2-methacryloyloxyethyl phosphoryl choline base-co-glycidyl methacrylate);

(4) Place the amino-containing polyethersulfone ultrafiltration membrane in 5 mg/mL poly(2-methacryloyloxyethylphosphorylcholine-co-glycidyl methacrylate) solution, followed by Add 100 μL triethylamine to 1 ml of poly(2-methacryloyloxyethylphosphorylcholine-co-glycidyl methacrylate) solution, and react at 90°C for 6 hours. Rinse with pure water three times and dry naturally to obtain anti-fouling polyethersulfone ultrafiltration membrane.

Comparative example 1

Compared with Example 1, the preparation method of the anti-pollution ultrafiltration membrane in the present invention is only different in that step (3) and step (4) are not performed, and the amino group-containing polyethersulfone ultrafiltration membrane is prepared.

sample analysis

(1) Morphology and elemental analysis

The XPS test results of the amino-containing polyethersulfone ultrafiltration membrane in Comparative Example 1 and the anti-fouling polyethersulfone ultrafiltration membrane in Example 3 are shown in A and B in Figure 1 respectively. Poly([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide-co-glycidyl methacrylate) was grafted on the ultrafiltration membrane to make the anti- A new N element peak appeared on the polluted polyethersulfone ultrafiltration membrane, corresponding to the ammonium ion group in the zwitterion, which proved the successful grafting of the epoxy-zwitterionic copolymer.

(2) Hydrophilic properties of anti-fouling ultrafiltration membranes

The anti-pollution polyethersulfone ultrafiltration membrane in Example 3 and the amino-containing polyethersulfone ultrafiltration membrane in Comparative Example 1 were respectively cut out of a certain area, and placed on a static water contact angle meter to measure the size of the water contact angle . As shown in Figure 2, the water contact angle of the anti-fouling polyethersulfone ultrafiltration membrane is significantly lower than that of the amino-containing polyethersulfone ultrafiltration membrane, and its hydrophilicity is excellent, with a water contact angle of 33°.

(3) Anti-protein fouling performance of anti-fouling ultrafiltration membrane

The embodiment and the comparative example middle membrane of certain area are respectively cut and placed in the cross-flow flat membrane performance evaluation device, under operating pressure 0.05MPa condition, by filtering the flux change of 1g/L bovine serum albumin solution (circulation content is : pure water 30min-bovine serum albumin solution 60min-cleaning 30min-pure water 30min), and finally measure the pure water flux recovery rate of the membrane.

As shown in Figure 3, compared with the amino-containing polyethersulfone ultrafiltration membrane in Comparative Example 1, the antifouling polyethersulfone ultrafiltration membrane in Example 3 exhibited a higher flux recovery rate and had good anti-fouling properties. Protein contamination capacity.

The pure water flux recovery rate results of the ultrafiltration membranes of Examples 1-8 and Comparative Example 1 are shown in Table 1. It can be seen that the grafting of epoxy-zwitterionic copolymers on the surface of the amino-containing ultrafiltration membrane has significantly improved the performance of the membrane. Excellent anti-protein pollution ability, under the condition of operating pressure of 0.05 MPa, the flux is maintained at about 140 L/m ² h.

The pure water flux recovery rate result of membrane in table 1 embodiment and comparative example

sample <![CDATA[Pure water flux L/m²h]]> Pure water flux recovery rate Example 1 138 94% Example 2 137 93% Example 3 140 98% Example 4 136 96% Example 5 138 94% Example 6 139 95% Example 7 136 97% Example 8 137 98% Comparative example 1 120 35%

(4) Anti-bacterial adhesion performance of anti-fouling ultrafiltration membrane

A certain area of the anti-pollution polyethersulfone ultrafiltration membrane in Example 3 and the amino-containing polyethersulfone ultrafiltration membrane in Comparative Example 1 were cut and placed in a 12-well plate, and Escherichia coli suspension was added. Then put it in a constant temperature shaking incubator and incubate at 37°C for a certain period of time. After the incubation, take out the membrane and wash it with PBS buffer three times, then place the membrane in glutaraldehyde solution and fix it overnight. After taking out the membrane, wash, A series of concentration gradient ethanol dehydration and sufficient drying took the SEM images of the membrane surface, the results are shown in Figure 4, where A is the amino-containing polyethersulfone ultrafiltration membrane of Comparative Example 1, and B is the anti-pollution polyether of Example 3 Sulfone ultrafiltration membrane; a large amount of Escherichia coli adheres to the surface of the amino-containing polyethersulfone ultrafiltration membrane, while there is almost no Escherichia coli adhesion on the surface of the anti-pollution polyethersulfone ultrafiltration membrane, which proves that the anti-pollution ultrafiltration membrane of the present invention has good anti-fouling properties. Bacterial adhesion ability.

The above-described embodiments have described the technical solutions of the present invention in detail. It should be understood that the above-described are only specific embodiments of the present invention, and are not intended to limit the present invention. Any modification, supplement or similar replacement etc. shall be included in the protection scope of the present invention.

Claims (5)

1. a preparation method of anti-pollution ultrafiltration membrane, is characterized in that, comprises the following steps: (1) Amination-modifying the polymer powder to obtain an amination-modified polymer powder; (2) Use the aminated modified polymer powder in step (1) to prepare the casting solution, then cast the casting solution on the support layer to form a film, then transfer it to the coagulation bath to solidify and form a wet film, and then wash and dry Obtain the amino-containing ultrafiltration membrane afterward; (3) Preparation of epoxy-zwitterionic copolymer by polymerization reaction of epoxy monomer, zwitterionic monomer and initiator as raw materials; (4) Grafting the epoxy-zwitterionic copolymer onto the amino group-containing ultrafiltration membrane in step (2) through an epoxy ring-opening reaction to obtain the anti-pollution ultrafiltration membrane; In step (3), the epoxy monomer is at least one of glycidyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether and allyl glycidyl ether; the zwitterionic monomer is [2-( Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide, 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propionate and at least one of 2-methacryloyloxyethyl phosphorylcholine; In step (3), the molar ratio of the epoxy monomer to the zwitterionic monomer is 1:9-9:1, and the amount of the initiator is 1-8 mol% of the total amount of the epoxy monomer and the zwitterionic monomer; In step (3), the polymerization reaction time is 3-10 h, and the temperature is 50-90°C; In step (4), the specific steps of the epoxy ring-opening reaction are: place the amino-containing ultrafiltration membrane in the epoxy-zwitterionic copolymer solution for grafting reaction, the grafting reaction temperature is 50-90°C, and the grafting reaction The reaction time is 6-24 h; The concentration of the epoxy-zwitterionic copolymer solution is 5-30 mg/mL. 2. The preparation method of anti-pollution ultrafiltration membrane according to claim 1, characterized in that, in step (1), the polymer powder is placed in an aqueous solution of amino monomer for amination modification; the amino monomer The body is at least one of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine. 3. The preparation method of anti-pollution ultrafiltration membrane according to claim 2, is characterized in that, the concentration of amino monomer aqueous solution is 5-20 wt%; The temperature of amination modification is 80-180 ℃, and the time is 20 -70 h. 4. The anti-pollution ultrafiltration membrane prepared according to the preparation method of the anti-pollution ultrafiltration membrane described in any one of claims 1-3. 5. The application of the anti-fouling ultrafiltration membrane according to claim 4 in the field of membrane separation.

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