Water treatment filtering material and preparation method thereof

Abstract

The invention discloses a water treatment filtering material and a preparation method thereof, and relates to the technical field of water treatment. When the water treatment filtering material is prepared, firstly, polyvinylidene fluoride reacts with 2-allylglycine, then reacts with 3-bromopropyl isocyanate, then reacts with hydantoin polyvinylidene fluoride, then reacts with mono (6-amino-6-deoxy)-beta-cyclodextrin, and after choline sulfate oxidation, the water treatment filtering material is obtained. Chloridizing with sodium hypochlorite to obtain modified polyvinylidene fluoride; secondly, enabling the diatomite pretreated by gamma-aminopropyltrimethoxysilane to react with tetraformyl phenyl porphyrin, so as to obtain modified diatomite; finally, the modified polyvinylidene fluoride and the modified diatomite are mixed to prepare a membrane, and the water treatment filtering material is prepared. The water treatment filtering material prepared by the invention has excellent adsorbability, antibacterial property and photocatalytic degradation property.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, in particular to a water treatment filter material and a preparation method thereof. Background Art

[0002] Water is the source of life and a necessary condition for the continuation of life. The rapid increase in population and the resulting expansion of industrial and agricultural scales have made water pollution increasingly serious. Pollutants in water mainly include heavy metal ions, microorganisms, organic dyes, aromatic compounds, etc. In order to solve the above-mentioned water pollution problem, the existing technology includes a variety of treatment technologies, including filtration, reverse osmosis, chemical precipitation, adsorption, catalytic degradation, etc. The adsorption method is widely used in water treatment research due to its advantages such as strong adsorption, less use of instruments, simple method and high efficiency.

[0003] Polyvinylidene fluoride has excellent thermal stability and chemical inertness and is expected to be used in complex water environments. However, the strong hydrophobicity of polyvinylidene fluoride membranes and the lack of functional groups on the surface make it impossible to efficiently adsorb a variety of pollutants in water, such as heavy metal ions, aromatic compounds, microorganisms and bacteria in water. The presence of these pollutants not only causes water pollution, but also corrodes the materials used for water treatment and reduces the service life of the materials. Therefore, it is necessary to prepare a water treatment material with good adsorption and antibacterial properties; at the same time, it is also possible to consider giving the water treatment material photocatalytic properties, so as to effectively degrade some organic matter into non-toxic small molecules such as carbon dioxide and water, so that the sewage can meet the requirements of no harmful emissions; combining adsorption and photocatalytic treatment technologies can greatly improve water treatment efficiency. Summary of the invention

[0004] The object of the present invention is to provide a water treatment filter material and a preparation method thereof to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The invention discloses a water treatment filter material, which is prepared by mixing modified polyvinylidene fluoride and modified diatomaceous earth to form a membrane.

[0007] As an optimization, the modified polyvinylidene fluoride is prepared by reacting polyvinylidene fluoride with 2-allylglycine, then with 3-bromopropyl isocyanate, then with hydantoin polyvinylidene fluoride, then with mono(6-amino-6-deoxy)-β-cyclodextrin, then with choline sulfate oxidation, and then with sodium hypochlorite chlorination.

[0008] As an optimization, the modified diatomaceous earth is prepared by reacting diatomaceous earth pretreated with γ-aminopropyltrimethoxysilane and tetraaldehyde phenylporphyrin.

[0009] A method for preparing a water treatment filter material, characterized in that it comprises the following preparation steps:

[0010] (1) polyvinylidene fluoride and N,N-dimethylformamide are mixed in a mass ratio of 1:30, heated to 50°C and stirred for 30 minutes, heated to 70°C under nitrogen protection, 0.05 times the mass of polyvinylidene fluoride terephthaloyl peroxide is added, stirred for 30 minutes, and 0.7-0.9 times the mass of polyvinylidene fluoride 2-allylglycine solution is added dropwise. After the addition is completed, the reaction is continued for 8 hours, and then 3-4 times the mass of N,N-dimethylformamide is added with anhydrous ethanol, filtered and washed with anhydrous ethanol for 3-4 times; pretreated polyvinylidene fluoride is obtained;

[0011] (2) Pretreated polyvinylidene fluoride and tetrahydrofuran were mixed in a mass ratio of 1:(30-40), the pH was adjusted to 9 using a 7.5M sodium hydroxide solution, 3-bromopropyl isocyanate in an amount of 10-12 times the mass of the pretreated polyvinylidene fluoride was added dropwise at 20-25°C at a rate of 1 mL / min, and a 7.5M sodium hydroxide solution was used to maintain the pH at 8.5-9. After the addition was completed, the reaction was continued for 1.5 hours, filtered, washed with anhydrous ethanol for 3-4 times, and vacuum dried at 50°C for 48 hours to obtain hyaluronic acid polyvinylidene fluoride;

[0012] (3) mixing hydantoin-based polyvinylidene fluoride, mono(6-amino-6-deoxy)-β-cyclodextrin, and 0.1 mol / L sodium bicarbonate solution with ammonia in a mass ratio of 1:(10-12):(30-40), reacting at 65-75° C. for 8-10 h, filtering, washing with anhydrous ethanol for 3-4 times, and vacuum drying at 50° C. for 48 h to obtain cyclodextrin-based polyvinylidene fluoride;

[0013] (4) mixing cyclodextrin-based polyvinylidene fluoride and choline persulfate in a mass ratio of 1:(10-12), reacting under nitrogen protection at 60°C for 1 hour, adding pure water 5-6 times the mass of choline persulfate, stirring for 3-5 minutes, filtering and washing with pure water 3-4 times to obtain pre-modified polyvinylidene fluoride; mixing pre-modified polyvinylidene fluoride and chlorination solution in a mass ratio of 1:(30-40) for 3-5 minutes, letting stand for 40 minutes, filtering and washing with pure water 5-6 times to obtain modified polyvinylidene fluoride;

[0014] (5) Pretreated diatomaceous earth, tetraaldehyde phenylporphyrin, trifluoroacetic acid and N,N-dimethylformamide are mixed uniformly in a mass ratio of 1:(2-3):(5-6):(50-60), degassed by three cycles of freezing-vacuuming-thawing, heated to 110-120° C. in a nitrogen atmosphere and sealed, stirred for reaction for 48-50 h at a stirring speed of 300-400 r / min, filtered after stirring, washed with pure water 3-4 times, and vacuum dried at 80° C. for 8 h to obtain modified diatomaceous earth;

[0015] (6) Modified polyvinylidene fluoride, modified diatomaceous earth, N-methylpyrrolidone and polyvinylpyrrolidone were mixed in a mass ratio of 1:(0.03-0.05):(5-6):(0.025-0.03), heated to 70°C, refluxed with stirring for 12 h and allowed to stand for 12 h to obtain a casting liquid, the casting liquid was drained onto a glass sheet with a glass rod, and then scraped into a smooth liquid film with a thickness of 0.2 mm with a scraper, the liquid film was placed in the air for 20 s, and then immersed in a 0.1 mol / L N-methylpyrrolidone solution for demolding to obtain a thin film, the thin film was taken out and washed with pure water for 3 times, and dried at room temperature for 8 h to obtain a water treatment filter material.

[0016] As an optimization, the polyvinylidene fluoride model in step (1) is FR904; the 2-allylglycine solution is obtained by mixing 2-allylglycine and N,N-dimethylformamide in a mass ratio of 1:30.

[0017] As an optimization, the chlorination solution in step (4) is obtained by adjusting the pH of a sodium hypochlorite solution having an active chlorine content of 500 ppm to 6 with 0.1 mol / L hydrochloric acid.

[0018] As an optimization, the preparation method of the pretreated diatomaceous earth in step (5) is as follows: diatomaceous earth and 3 mol / L nitric acid are mixed in a mass ratio of 1:30, stirred at 70°C for 8 hours, filtered, washed with pure water for 5-6 times, vacuum dried at 80°C for 8 hours, sieved through a 150-mesh sieve to obtain spare diatomaceous earth, and spare diatomaceous earth, γ-aminopropyltrimethoxysilane, and anhydrous ethanol are mixed in a mass ratio of 1:(3-4):(20-30), stirred at 70°C for 24 hours, cooled to room temperature, filtered, washed with pure water for 3-4 times, and vacuum dried at 80°C for 8 hours to obtain pretreated diatomaceous earth.

[0019] As an optimization, the diatomaceous earth has a particle size of 800 meshes and a silicon dioxide content of 80%-94%.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0021] When preparing the water treatment filter material, the present invention firstly reacts polyvinylidene fluoride with 2-allylglycine, then reacts with 3-bromopropyl isocyanate, then reacts with hydantoin polyvinylidene fluoride, then reacts with mono(6-amino-6-deoxy)-β-cyclodextrin, oxidizes with choline sulfate, and then chlorinates with sodium hypochlorite to obtain modified polyvinylidene fluoride; secondly, diatomaceous earth pretreated with gamma-aminopropyltrimethoxysilane reacts with tetraaldehyde phenylporphyrin to obtain modified diatomaceous earth; finally, the modified polyvinylidene fluoride and the modified diatomaceous earth are mixed and then film-formed to obtain the water treatment filter material.

[0022] Firstly, polyvinylidene fluoride is grafted with 2-allylglycine, and then reacted with 3-bromopropyl isocyanate to generate a hydantoin structure containing a brominated alkyl group. The brominated alkyl group reacts with mono(6-amino-6-deoxy)-β-cyclodextrin to generate a secondary amine, which is then grafted with an external hydrophilic cyclodextrin, thereby improving the hydrophilicity of the water treatment material. The addition of choline persulfate can selectively oxidize the secondary amine into hydroxylamine. The hydroxylamine structure has the ability to capture free radicals and decompose hydroperoxides, thereby improving the anti-aging ability of the water treatment material. The chlorination of sodium hypochlorite can convert the hydantoin structure on the material into a halamine with antibacterial properties, thereby giving the water treatment material good antibacterial properties.

[0023] Secondly, the modified diatomite is prepared by reacting the diatomite pretreated with γ-aminopropyltrimethoxysilane with tetraaldehyde phenylporphyrin; the surface of the diatomite treated with γ-aminopropyltrimethoxysilane has abundant amino groups, which can react with the aldehyde groups on the tetraaldehyde phenylporphyrin to form a Schiff base reaction, thereby grafting porphyrin on the surface of the diatomite. Porphyrin can complex heavy metal ions in wastewater and has excellent photocatalytic ability, which can effectively decompose organic matter in wastewater;

[0024] Finally, modified polyvinylidene fluoride and modified diatomite are mixed to form a membrane to obtain a water treatment filter material. Under the action of the porogen, the modified polyvinylidene fluoride diffuses between the liquid film / coagulation bath interface, and the casting liquid gradually undergoes phase separation, coagulation and interphase flow to eventually form an independent porous film. The porous structure can increase the adsorption of pollutants. The cyclodextrin on the modified polyvinylidene fluoride can complex with the aldehyde benzene on the porphyrin on the surface of the modified diatomite to form a cross-linked network, thereby enhancing the mechanical properties of the water treatment material. The remaining cyclodextrin can effectively adsorb some small molecules containing phenol structure through the internal hydrophobic cavity. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The polyvinylidene fluoride used in the following examples and comparative examples is FR904; the 2-allylglycine solution used is obtained by mixing 2-allylglycine and N,N-dimethylformamide in a mass ratio of 1:30; the diatomaceous earth used has a particle size of 800 mesh and a silicon dioxide content of 80%-94%; the chlorination solution used is obtained by adjusting the pH of a sodium hypochlorite solution having an active chlorine content of 500 ppm to 6 by using 0.1 mol / L hydrochloric acid.

[0027] Embodiment 1:

[0028] A method for preparing a water treatment filter material, the method comprising the following steps:

[0029] (1) polyvinylidene fluoride and N,N-dimethylformamide are mixed in a mass ratio of 1:30, heated to 50°C and stirred for 30 minutes, heated to 70°C under nitrogen protection, 0.05 times the mass of terephthaloyl peroxide of the polyvinylidene fluoride is added, stirred for 30 minutes, and 0.7 times the mass of 2-allylglycine solution of the polyvinylidene fluoride is added dropwise. After the addition is completed, the reaction is continued for 8 hours, and then 3-4 times the mass of N,N-dimethylformamide is added with anhydrous ethanol, filtered and washed with anhydrous ethanol for 3 times; pretreated polyvinylidene fluoride is obtained;

[0030] (2) Pretreated polyvinylidene fluoride and tetrahydrofuran were mixed at a mass ratio of 1:30, and the pH was adjusted to 9 using a 7.5M sodium hydroxide solution. 3-bromopropyl isocyanate in an amount 10 times the mass of the pretreated polyvinylidene fluoride was added dropwise at 25°C at a rate of 1 mL / min, and a 7.5M sodium hydroxide solution was used to maintain the pH at 8.5. After the addition was completed, the reaction was continued for 1.5 hours, filtered, washed with anhydrous ethanol for 3 times, and vacuum dried at 50°C for 48 hours to obtain hyaluronic acid polyvinylidene fluoride;

[0031] (3) mixing hydantoin-based polyvinylidene fluoride, mono(6-amino-6-deoxy)-β-cyclodextrin, and 0.1 mol / L sodium bicarbonate solution in a mass ratio of 1:10:30, reacting at 75° C. for 10 h, filtering, washing with anhydrous ethanol for 3 times, and vacuum drying at 50° C. for 48 h to obtain cyclodextrin-based polyvinylidene fluoride;

[0032] (4) Mixing cyclodextrin-based polyvinylidene fluoride and choline persulfate in a mass ratio of 1:10, reacting under nitrogen protection at 60°C for 1 hour, adding pure water 5 times the mass of choline persulfate, stirring for 5 minutes, filtering and washing with pure water 3 times to obtain pre-modified polyvinylidene fluoride; mixing pre-modified polyvinylidene fluoride and chlorination solution in a mass ratio of 1:30 for 5 minutes, letting stand for 40 minutes, filtering and washing with pure water 6 times to obtain modified polyvinylidene fluoride;

[0033] (5) diatomaceous earth and 3 mol / L nitric acid were mixed in a mass ratio of 1:30, stirred at 70°C for 8 h, filtered, washed with pure water for 6 times, vacuum dried at 80°C for 8 h, and passed through a 150-mesh sieve to obtain standby diatomaceous earth; standby diatomaceous earth, γ-aminopropyltrimethoxysilane, and anhydrous ethanol were mixed in a mass ratio of 1:3:20, stirred at 70°C for 24 h, cooled to room temperature, filtered, washed with pure water for 3 times, and vacuum dried at 80°C for 8 h; Pretreated diatomaceous earth is obtained; the pretreated diatomaceous earth, tetraaldehyde phenylporphyrin, trifluoroacetic acid and N,N-dimethylformamide are mixed uniformly in a mass ratio of 1:2:5:50, and degassed by three cycles of freezing-vacuuming-thawing. In a nitrogen atmosphere and sealed conditions, the temperature is raised to 120° C., and the reaction is stirred for 50 hours at a stirring speed of 400 r / min. After the stirring is completed, the mixture is filtered and washed with pure water for 4 times, and vacuum dried at 80° C. for 8 hours to obtain modified diatomaceous earth;

[0034] (6) Modified polyvinylidene fluoride, modified diatomaceous earth, N-methylpyrrolidone and polyvinylpyrrolidone were mixed in a mass ratio of 1:0.03:5:0.025, heated to 70°C, refluxed with stirring for 12 h and allowed to stand for 12 h to obtain a casting liquid, the casting liquid was drained onto a glass sheet with a glass rod, and then scraped into a smooth liquid film with a thickness of 0.2 mm with a scraper, the liquid film was placed in the air for 20 s, and then immersed in a 0.1 mol / L N-methylpyrrolidone solution for demolding to obtain a thin film, the thin film was taken out and washed with pure water three times, and dried at room temperature for 8 h to obtain a water treatment filter material.

[0035] Embodiment 2:

[0036] A method for preparing a water treatment filter material, the method comprising the following steps:

[0037] (1) polyvinylidene fluoride and N,N-dimethylformamide are mixed in a mass ratio of 1:30, heated to 50°C and stirred for 30 minutes, heated to 70°C under nitrogen protection, 0.05 times the mass of terephthaloyl peroxide of the polyvinylidene fluoride is added, stirred for 30 minutes, and 0.8 times the mass of 2-allylglycine solution of the polyvinylidene fluoride is added dropwise. After the addition is completed, the reaction is continued for 8 hours, and then 3-4 times the mass of N,N-dimethylformamide is added with anhydrous ethanol, filtered and washed with anhydrous ethanol for 3-4 times; pretreated polyvinylidene fluoride is obtained;

[0038] (2) Pretreated polyvinylidene fluoride and tetrahydrofuran were mixed in a mass ratio of 1:35, and the pH was adjusted to 9 using a 7.5M sodium hydroxide solution. 3-bromopropyl isocyanate with a mass of 11 times that of the pretreated polyvinylidene fluoride was added dropwise at 23°C at a rate of 1 mL / min, and a 7.5M sodium hydroxide solution was used to maintain the pH at 8.7. After the addition was completed, the reaction was continued for 1.5 hours, filtered, washed with anhydrous ethanol for 3 times, and vacuum dried at 50°C for 48 hours to obtain hyaluronic acid polyvinylidene fluoride;

[0039] (3) mixing hydantoin-based polyvinylidene fluoride, mono(6-amino-6-deoxy)-β-cyclodextrin, and 0.1 mol / L sodium bicarbonate solution in a mass ratio of 1:11:35, reacting at 60° C. for 9 h, filtering, washing with anhydrous ethanol for 3 times, and vacuum drying at 50° C. for 48 h to obtain cyclodextrin-based polyvinylidene fluoride;

[0040] (4) Mix cyclodextrin-based polyvinylidene fluoride and choline persulfate in a mass ratio of 1:11, react under nitrogen protection at 60°C for 1 hour, add pure water 5 times the mass of choline persulfate, stir for 4 minutes, filter and wash with pure water 3 times to obtain pre-modified polyvinylidene fluoride; mix pre-modified polyvinylidene fluoride and chlorination solution in a mass ratio of 1:35 for 4 minutes, let stand for 40 minutes, filter and wash with pure water 5 times to obtain modified polyvinylidene fluoride;

[0041] (5) diatomaceous earth and 3 mol / L nitric acid were mixed in a mass ratio of 1:30, stirred at 70°C for 8 h, filtered, washed with pure water 5 times, vacuum dried at 80°C for 8 h, and passed through a 150-mesh sieve to obtain spare diatomaceous earth; spare diatomaceous earth, γ-aminopropyltrimethoxysilane, and anhydrous ethanol were mixed in a mass ratio of 1:3.5:25, stirred at 70°C for 24 h, cooled to room temperature, filtered, washed with pure water 3 times, and vacuum dried at 80°C for 8 h to obtain to pretreated diatomaceous earth; the pretreated diatomaceous earth, tetraaldehyde phenylporphyrin, trifluoroacetic acid and N, N-dimethylformamide were mixed uniformly in a mass ratio of 1:2.5:5.5:55, and degassed by three cycles of freezing-vacuuming-thawing, and heated to 115°C in a nitrogen atmosphere and sealed conditions, and stirred for reaction for 49 hours at a stirring speed of 350 r / min. After the stirring was completed, the mixture was filtered and washed with pure water for 3 times, and vacuum dried at 80°C for 8 hours to obtain modified diatomaceous earth;

[0042] (6) Modified polyvinylidene fluoride, modified diatomaceous earth, N-methylpyrrolidone and polyvinylpyrrolidone were mixed in a mass ratio of 1:0.04:5.5:0.027, heated to 70°C, refluxed with stirring for 12 h and allowed to stand for 12 h to obtain a casting liquid, the casting liquid was drained onto a glass sheet with a glass rod, and then scraped into a smooth liquid film with a thickness of 0.2 mm with a scraper, the liquid film was placed in the air for 20 s, and then immersed in a 0.1 mol / L N-methylpyrrolidone solution for demolding to obtain a thin film, the thin film was taken out and washed with pure water three times, and dried at room temperature for 8 h to obtain a water treatment filter material.

[0043] Embodiment 3:

[0044] A method for preparing a water treatment filter material, the method comprising the following steps:

[0045] (1) polyvinylidene fluoride and N,N-dimethylformamide are mixed in a mass ratio of 1:30, heated to 50°C and stirred for 30 minutes, heated to 70°C under nitrogen protection, 0.05 times the mass of terephthaloyl peroxide of the polyvinylidene fluoride is added, stirred for 30 minutes, and 0.9 times the mass of 2-allylglycine solution of the polyvinylidene fluoride is added dropwise. After the addition is completed, the reaction is continued for 8 hours, and then 3-4 times the mass of N,N-dimethylformamide is added with anhydrous ethanol, filtered and washed with anhydrous ethanol for 3-4 times; pretreated polyvinylidene fluoride is obtained;

[0046] (2) Pretreated polyvinylidene fluoride and tetrahydrofuran were mixed in a mass ratio of 1:40, and the pH was adjusted to 9 using a 7.5M sodium hydroxide solution. 3-bromopropyl isocyanate in an amount 12 times the mass of the pretreated polyvinylidene fluoride was added dropwise at 20°C at a rate of 1 mL / min, and a 7.5M sodium hydroxide solution was used to maintain the pH at 9. After the addition was completed, the reaction was continued for 1.5 hours, filtered, washed with anhydrous ethanol for 3 times, and vacuum dried at 50°C for 48 hours to obtain hyaluronic acid polyvinylidene fluoride;

[0047] (3) mixing hydantoin-based polyvinylidene fluoride, mono(6-amino-6-deoxy)-β-cyclodextrin, and 0.1 mol / L sodium bicarbonate solution in a mass ratio of 1:12:40, reacting at 65-75° C. for 8 h, filtering, washing with anhydrous ethanol for 3 times, and vacuum drying at 50° C. for 48 h to obtain cyclodextrin-based polyvinylidene fluoride;

[0048] (4) Mix cyclodextrin-based polyvinylidene fluoride and choline persulfate in a mass ratio of 1:12, react under nitrogen protection at 60°C for 1 hour, add pure water 6 times the mass of choline persulfate, stir for 3 minutes, filter and wash with pure water 3 times to obtain pre-modified polyvinylidene fluoride; mix the pre-modified polyvinylidene fluoride and chlorination solution in a mass ratio of 1:40 for 3 minutes, let stand for 40 minutes, filter and wash with pure water 5 times to obtain modified polyvinylidene fluoride;

[0049] (5) Mix diatomaceous earth and 3 mol / L nitric acid in a mass ratio of 1:30, stir at 70°C for 8 h, filter, wash with pure water 5 times, vacuum dry at 80°C for 8 h, pass through a 150-mesh sieve to obtain spare diatomaceous earth, mix spare diatomaceous earth, γ-aminopropyltrimethoxysilane, and anhydrous ethanol in a mass ratio of 1:4:30, stir at 70°C for 24 h, cool to room temperature, filter, wash with pure water 3-4 times, and vacuum dry at 80°C for 8 h. , obtaining pretreated diatomaceous earth; mixing the pretreated diatomaceous earth, tetraaldehyde phenylporphyrin, trifluoroacetic acid and N,N-dimethylformamide in a mass ratio of 1:3:6:60, degassing by three cycles of freezing-vacuuming-thawing, heating to 110°C in a nitrogen atmosphere and sealed condition, stirring for 48 hours, stirring at a speed of 300 r / min, filtering after the stirring, washing with pure water three times, and vacuum drying at 80°C for 8 hours to obtain modified diatomaceous earth;

[0050] (6) Modified polyvinylidene fluoride, modified diatomaceous earth, N-methylpyrrolidone and polyvinylpyrrolidone were mixed in a mass ratio of 1:0.05:6:0.03, heated to 70°C, refluxed with stirring for 12 h and allowed to stand for 12 h to obtain a casting liquid, the casting liquid was drained onto a glass sheet with a glass rod, and then scraped into a smooth liquid film with a thickness of 0.2 mm with a scraper, the liquid film was placed in the air for 20 s, and then immersed in a 0.1 mol / L N-methylpyrrolidone solution for demolding to obtain a thin film, the thin film was taken out and washed with pure water three times, and dried at room temperature for 8 h to obtain a water treatment filter material.

[0051] Comparative Example 1:

[0052] The difference between the preparation method of the water treatment filter material of Comparative Example 1 and Example 2 is that step (4) is modified as follows: cyclodextrin-based polyvinylidene fluoride and choline persulfate are mixed in a mass ratio of 1:11, reacted at 60°C for 1 hour under nitrogen protection, pure water 5 times the mass of choline persulfate is added, stirred for 4 minutes, filtered and washed 3 times with pure water to obtain modified polyvinylidene fluoride.

[0053] Comparative Example 2:

[0054] The preparation method of the water treatment filter material of Comparative Example 2 differs from that of Example 2 in that step (4) is modified as follows: cyclodextrin-based polyvinylidene fluoride and chlorination solution are mixed at a mass ratio of 1:35 for 4 minutes, and then allowed to stand for 40 minutes, filtered and washed with pure water 5 times to obtain modified polyvinylidene fluoride.

[0055] Comparative Example 3:

[0056] The preparation method of the water treatment filter material in Comparative Example 3 differs from that in Example 2 in that step (5) is not included, and step (6) is modified as follows: modified polyvinylidene fluoride, diatomaceous earth, N-methylpyrrolidone, and polyvinylpyrrolidone are mixed in a mass ratio of 1:0.05:6:0.03, the temperature is raised to 70°C, refluxed with stirring for 12 hours, and allowed to stand for 12 hours to obtain a casting liquid, the casting liquid is drained onto a glass sheet with a glass rod, and then scraped into a smooth liquid film with a thickness of 0.2 mm with a scraper, the liquid film is placed in the air for 20 seconds, and then immersed in a 0.1 mol / L N-methylpyrrolidone solution for demolding to obtain a thin film, the thin film is taken out and washed with pure water 3 times, and dried at room temperature for 8 hours to obtain a water treatment filter material.

[0057] Test Example 1:

[0058] Antibacterial performance test:

[0059] Test method: The antibacterial rate test was performed on the water treatment filter materials prepared in the examples and comparative examples according to the standard GB 15979-2002. The results are shown in Table 1.

[0060] Table 1

[0061] Antibacterial rate (%) Antibacterial rate (%) Example 1 96.21 Comparative Example 1 13.24 Example 2 95.78 Comparative Example 2 95.81 Example 3 96.25 Comparative Example 3 95.64

[0062] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1, it can be found that the water treatment filter material prepared by the present invention has good antibacterial properties.

[0063] By comparison, the antibacterial rates of Examples 1 to 3 are greater than that of Comparative Example 1, indicating that first, polyvinylidene fluoride is reacted with 2-allyl glycine, then with 3-bromopropyl isocyanate, then with hydantoin-based polyvinylidene fluoride, then with mono(6-amino-6-deoxy)-β-cyclodextrin, oxidized with choline sulfate, and then chlorinated with sodium hypochlorite to obtain modified polyvinylidene fluoride; polyvinylidene fluoride is grafted with 2-allyl glycine, and then reacted with 3-bromopropyl isocyanate to generate a hydantoin structure containing a bromoalkyl group, and the chlorination with sodium hypochlorite can convert the hydantoin structure on the material into a halamine with antibacterial properties, thereby giving the water treatment material good antibacterial properties.

[0064] Test Example 2:

[0065] Adsorption performance test:

[0066] Copper sulfate pentahydrate was prepared into a 5 mg / L copper ion solution; the water treatment material prepared in the embodiment and the comparative example and the copper ion solution were mixed at a mass ratio of 1:40, and oscillated at 120 rpm for 120 min at 30°C, then the water treatment material was taken out, and the copper ion content in the supernatant was determined by flame atomic absorption spectrometry, and the copper ion removal rate was calculated. The results are shown in Table 2.

[0067] Photocatalytic degradation performance test:

[0068] The water treatment materials prepared in the embodiment and the comparative example and 50 mg / L methylene blue solution were mixed at a mass ratio of 1:1 for 20 min, and a photocatalytic degradation experiment was carried out using a YM-GHX-I photocatalytic reactor, the light source was a 300W xenon lamp, the xenon lamp emission wavelength range was 360-780nm, the light source distance was 10 cm, and then the precipitate was separated by a magnet, the supernatant was collected, the methylene blue concentration was determined by spectrophotometry, and the degradation rate of methylene blue was calculated. The results are shown in Table 2.

[0069] Table 2

[0070] Copper ion removal rate (%) Methylene blue degradation rate (%) Example 1 87.13 92.75 Example 2 86.74 92.51 Example 3 87.32 93.04 Comparative Example 1 86.71 92.33 Comparative Example 2 86.59 92.54 Comparative Example 3 53.27 73.24

[0071] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 2, it can be found that the water treatment filter material prepared by the present invention has good adsorption and photocatalytic degradation properties.

[0072] By comparison, the copper ion removal rates of Examples 1 to 3 are greater than that of Comparative Example 3, and the methylene blue degradation rates of Examples 1 to 3 are greater than that of Comparative Example 3, indicating that the modified diatomaceous earth prepared by reacting diatomaceous earth pretreated with γ-aminopropyltrimethoxysilane with tetraaldehyde phenylporphyrin; the surface of the diatomaceous earth treated with γ-aminopropyltrimethoxysilane has abundant amino groups, which can react with the aldehyde groups on the tetraaldehyde phenylporphyrin to undergo Schiff base reaction, thereby grafting porphyrin on the surface of the diatomaceous earth, and porphyrin can complex heavy metal ions in the wastewater, and has excellent photocatalytic ability, and can effectively decompose organic matter in the wastewater.

[0073] Embodiment 3:

[0074] Anti-aging performance test:

[0075] Test method: According to the standard of GB / T1040.2-2006, the water treatment materials prepared in the embodiments and comparative examples were tested for breaking strength on a tensile testing machine, with a gauge length of 20 mm and a tensile speed of 5 mm / min. All the water treatment materials prepared in the embodiments and comparative examples were laid flat on a sample rack and then placed in an aging box, with an aging temperature of 50°C, a relative humidity of 55%, an ozone concentration of 450 pphm, and an aging time of 360 h. After the aging, the breaking strength was tested and the breaking strength retention rate before and after aging was calculated. The results are shown in Table 3.

[0076] Table 3

[0077] Retention rate of breaking strength (%) Retention rate of breaking strength (%) Example 1 82.46 Comparative Example 1 82.34 Example 2 82.37 Comparative Example 2 56.37 Example 3 83.01 Comparative Example 3 82.33

[0078] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 2, it can be found that the water treatment filter material prepared by the present invention has good adsorption and photocatalytic degradation properties.

[0079] By comparison, the fracture strength retention rates of Examples 1 to 3 are greater than that of Comparative Example 2, indicating that the modified polyvinylidene fluoride is prepared by reacting polyvinylidene fluoride with 2-allyl glycine, then reacting with 3-bromopropyl isocyanate, then reacting with hydantoin polyvinylidene fluoride, then reacting with mono (6-amino-6-deoxy)-β-cyclodextrin, oxidizing with choline sulfate, and then chlorinating with sodium hypochlorite; first, polyvinylidene fluoride is grafted with 2-allyl glycine, and then reacting with 3-bromopropyl isocyanate to generate a hydantoin structure containing a bromoalkyl group, the bromoalkyl group reacts with mono (6-amino-6-deoxy)-β-cyclodextrin to generate a secondary amine and grafting an externally hydrophilic cyclodextrin, thereby improving the hydrophilicity of the water treatment material, and the addition of choline persulfate can selectively oxidize the secondary amine into hydroxylamine, and the hydroxylamine structure has the ability to capture free radicals and decompose hydroperoxides, thereby improving the anti-aging of the water treatment material.

[0080] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A water treatment filter material, characterized in that: The water treatment filter material is prepared by mixing modified polyvinylidene fluoride and modified diatomaceous earth to form a membrane; The modified polyvinylidene fluoride is prepared by reacting polyvinylidene fluoride with 2-allylglycine, then with 3-bromopropyl isocyanate, then with hydantoin polyvinylidene fluoride, then with mono(6-amino-6-deoxy)-β-cyclodextrin, then with choline sulfate oxidation, and then with sodium hypochlorite chlorination; The modified diatomaceous earth is prepared by reacting diatomaceous earth pretreated with gamma-aminopropyltrimethoxysilane and tetraaldehyde phenylporphyrin.

2. A method for preparing a water treatment filter material, characterized in that: The method comprises the following preparation steps: (1) polyvinylidene fluoride and N,N-dimethylformamide are mixed in a mass ratio of 1:30, heated to 50°C and stirred for 30 minutes, heated to 70°C under nitrogen protection, 0.05 times the mass of polyvinylidene fluoride terephthaloyl peroxide is added, stirred for 30 minutes, and 0.7-0.9 times the mass of polyvinylidene fluoride 2-allylglycine solution is added dropwise. After the addition is completed, the reaction is continued for 8 hours, and then 3-4 times the mass of N,N-dimethylformamide is added with anhydrous ethanol, filtered and washed with anhydrous ethanol for 3-4 times; pretreated polyvinylidene fluoride is obtained; (2) Pretreated polyvinylidene fluoride and tetrahydrofuran were mixed in a mass ratio of 1:(30-40), the pH was adjusted to 9 using a 7.5M sodium hydroxide solution, 3-bromopropyl isocyanate in an amount of 10-12 times the mass of the pretreated polyvinylidene fluoride was added dropwise at 20-25°C at a rate of 1 mL / min, and a 7.5M sodium hydroxide solution was used to maintain the pH at 8.5-9. After the addition was completed, the reaction was continued for 1.5 hours, filtered, washed with anhydrous ethanol for 3-4 times, and vacuum dried at 50°C for 48 hours to obtain hyaluronic acid polyvinylidene fluoride; (3) mixing hydantoin-based polyvinylidene fluoride, mono(6-amino-6-deoxy)-β-cyclodextrin, and 0.1 mol / L sodium bicarbonate solution with ammonia in a mass ratio of 1:(10-12):(30-40), reacting at 65-75° C. for 8-10 h, filtering, washing with anhydrous ethanol for 3-4 times, and vacuum drying at 50° C. for 48 h to obtain cyclodextrin-based polyvinylidene fluoride; (4) mixing cyclodextrin-based polyvinylidene fluoride and choline persulfate in a mass ratio of 1:(10-12), reacting under nitrogen protection at 60°C for 1 hour, adding pure water 5-6 times the mass of choline persulfate, stirring for 3-5 minutes, filtering and washing with pure water 3-4 times to obtain pre-modified polyvinylidene fluoride; mixing pre-modified polyvinylidene fluoride and chlorination solution in a mass ratio of 1:(30-40) for 3-5 minutes, letting stand for 40 minutes, filtering and washing with pure water 5-6 times to obtain modified polyvinylidene fluoride; (5) Pretreated diatomaceous earth, tetraaldehyde phenylporphyrin, trifluoroacetic acid and N,N-dimethylformamide are mixed uniformly in a mass ratio of 1:(2-3):(5-6):(50-60), degassed by three cycles of freezing-vacuuming-thawing, heated to 110-120° C. in a nitrogen atmosphere and sealed, stirred for reaction for 48-50 h at a stirring speed of 300-400 r / min, filtered after stirring, washed with pure water 3-4 times, and vacuum dried at 80° C. for 8 h to obtain modified diatomaceous earth; (6) Modified polyvinylidene fluoride, modified diatomaceous earth, N-methylpyrrolidone and polyvinylpyrrolidone were mixed in a mass ratio of 1:(0.03-0.05):(5-6):(0.025-0.03), heated to 70°C, refluxed with stirring for 12 h and allowed to stand for 12 h to obtain a casting liquid, the casting liquid was drained onto a glass sheet with a glass rod, and then scraped into a smooth liquid film with a thickness of 0.2 mm with a scraper, the liquid film was placed in the air for 20 s, and then immersed in a 0.1 mol / L N-methylpyrrolidone solution for demolding to obtain a thin film, the thin film was taken out and washed with pure water for 3 times, and dried at room temperature for 8 h to obtain a water treatment filter material.

3. The method for preparing a water treatment filter material according to claim 2, characterized in that: The polyvinylidene fluoride model in step (1) is FR904; the 2-allylglycine solution is obtained by mixing 2-allylglycine and N,N-dimethylformamide in a mass ratio of 1:

30.

4. The method for preparing a water treatment filter material according to claim 2, characterized in that: The chlorinated solution in step (4) is obtained by adjusting the pH of a sodium hypochlorite solution having an active chlorine content of 500 ppm to 6 with 0.1 mol / L hydrochloric acid.

5. The method for preparing a water treatment filter material according to claim 2, characterized in that: The preparation method of the pretreated diatomaceous earth in step (5) is as follows: diatomaceous earth and 3 mol / L nitric acid are mixed in a mass ratio of 1:30, stirred at 70°C for 8h, filtered, washed with pure water for 5-6 times, vacuum dried at 80°C for 8h, sieved through a 150-mesh sieve to obtain spare diatomaceous earth, and spare diatomaceous earth, γ-aminopropyltrimethoxysilane, and anhydrous ethanol are mixed in a mass ratio of 1:(3-4):(20-30), stirred at 70°C for 24h, cooled to room temperature, filtered, washed with pure water for 3-4 times, and vacuum dried at 80°C for 8h to obtain pretreated diatomaceous earth.

6. The method for preparing a water treatment filter material according to claim 5, characterized in that: The diatomaceous earth has a particle size of 800 meshes and a silicon dioxide content of 80%-94%.