Conformal hydrophilic modification method of polymer separation membrane material

Abstract

The embodiment of the invention discloses a shape follow-up hydrophilic modification method of a polymer separation membrane material, and the shape follow-up hydrophilic modification method comprises the following steps: pretreating the polymer separation membrane material to obtain a pretreated polymer separation membrane material; contacting the to-be-modified side of the pretreated polymer separation membrane material with a modification solution I to obtain a first modified polymer separation membrane material; and after the to-be-modified side of the polymer separation membrane material modified for the first time is in contact with a modification solution II, rinsing is performed, and the shape follow-up hydrophilic modification of the polymer separation membrane material is completed.

Description

Technical Field

[0001] This invention relates to the field of polymer separation membrane materials technology, and in particular to a conformal hydrophilic modification method for polymer separation membrane materials. Background Technology

[0002] Membrane separation is a highly efficient and energy-saving purification and concentration technology. Because it does not involve phase changes or high-temperature operations, the properties of the enriched and concentrated substances are less likely to change, giving membrane separation an inherent advantage in industries such as food and pharmaceuticals. Depending on the specific species to be separated, the scale of the materials, the required separation precision, and cost control, users often select membrane elements of different types and materials for filtration. Common membrane element types include flat sheet membranes, hollow fiber membranes, tubular membranes, and spiral wound membranes. Membrane materials mainly include polysulfone, polyethersulfone, polytetrafluoroethylene, polyvinylidene fluoride, polylactic acid, and polypropylene (collectively referred to as polymer separation membrane materials). Polymer separation membrane materials are mostly hydrophobic; during application, complex components in the material easily accumulate on the membrane material, leading to membrane fouling and a significant decrease in separation efficiency.

[0003] Therefore, it is essential to improve the hydrophilicity of polymer separation membrane materials. In the existing technology, the hydrophilic modification of polymer separation membrane materials is mostly achieved through surface coating and surface grafting, but the existing technology still has the following problems. (1) The adhesion between the hydrophilic agent and the membrane substrate is weak, and it cannot play a long-term role: For example, physical coating of polyvinyl alcohol is a common hydrophilic modification method, but the hydrophilic layer will gradually be lost during use. (2) The hydrophilic agent has charge, and its electrostatic attraction with pollutants may aggravate membrane fouling: For example, polyethyleneimine is often used as the cationic layer in the layer-by-layer hydrophilization process, and it easily adsorbs negatively charged microorganisms and proteins. (3) The applicability of some hydrophilic modification methods is limited: For example, the irradiation modification method represented by photoinduced graft polymerization can only treat the outermost layer of the membrane material, and requires the irradiated surface to be flat, without bending or folding, in order to ensure the uniformity of irradiation grafting, making it difficult to achieve conformal modification. Therefore, it is particularly important to develop a new method for hydrophilic modification of polymer separation membrane materials to solve the problems of poor stability, high charge, and limited applicability of existing technologies.

[0004] Based on this, the embodiments of this specification provide a conformal hydrophilic modification method for polymer separation membrane materials. Summary of the Invention

[0005] This specification provides a conformal hydrophilic modification method for polymer separation membrane materials to solve the following technical problems: In the prior art, the hydrophilic modification of polymer separation membrane materials is mostly achieved through surface coating and surface grafting, but the prior art still has the following problems. (1) The adhesion between the hydrophilic agent and the membrane substrate is weak, and it cannot play a long-term role: For example, physical coating of polyvinyl alcohol is a common hydrophilic modification method, but the hydrophilic layer will gradually be lost during use. (2) The hydrophilic agent has charge, and the electrostatic attraction between it and pollutants may aggravate membrane fouling: For example, polyethyleneimine is often used as the cationic layer in the layer-by-layer assembly hydrophilization process, and it easily adsorbs negatively charged microorganisms and proteins. (3) The applicability of some hydrophilic modification methods is limited: For example, irradiation modification methods represented by photoinduced graft polymerization can only treat the outermost layer of the membrane material, and require the irradiated surface to be flat, without bending or folding, in order to ensure the uniformity of irradiation grafting, making it difficult to achieve conformal modification.

[0006] To solve the above-mentioned technical problems, the embodiments in this specification are implemented as follows:

[0007] This specification provides an embodiment of a method for conformal hydrophilic modification of a polymer separation membrane material, the method comprising:

[0008] The polymer separation membrane material is pretreated to obtain a pretreated polymer separation membrane material;

[0009] The pretreated polymer separation membrane material to be modified is brought into contact with the modification solution I to obtain the first modified polymer separation membrane material;

[0010] After the side of the polymer separation membrane material to be modified is brought into contact with the modification solution II, it is rinsed to complete the conformal hydrophilic modification of the polymer separation membrane material.

[0011] This specification provides a conformal hydrophilic modification method for polymer separation membrane materials. Through a chemical reaction, a hydrophilic agent is stably loaded onto the surface of the polymer separation membrane material, overcoming the drawback of easy hydrophilic agent loss in existing technologies. Simultaneously, the modification process is unrestricted in terms of the shape, morphology, and flatness of the membrane surface to be modified, achieving conformal modification. Furthermore, the hydrophilic agent is electrically neutral, which can reduce the deposition of pollutants caused by electrostatic attraction. The technical solution proposed in this invention is simple to operate and easily scaled up industrially. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a conformal hydrophilic modification method for a polymer separation membrane material provided in the embodiments of this specification. Detailed Implementation

[0013] To better understand the technical solution of the present invention, the following embodiments will further illustrate the method provided by the present invention. However, the present invention is not limited to the listed embodiments, but should also include any other well-known modifications within the scope of the claims of the present invention.

[0014] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0015] Materials used in this invention: There are no special restrictions on the source of all raw materials in this invention and the following embodiments and comparative examples; they can be commercially available.

[0016] Figure 1 This is a schematic diagram illustrating a conformal hydrophilic modification method for a polymer separation membrane material provided in the embodiments of this specification. Figure 1 As shown, the conformal hydrophilic modification method includes:

[0017] Step S101: Pre-treat the polymer separation membrane material to obtain the pre-treated polymer separation membrane material.

[0018] In the embodiments of this specification, the polymer separation membrane material includes: flat sheet membrane, hollow fiber membrane, and tubular membrane;

[0019] The polymer separation membrane material comprises: polysulfone, polyethersulfone, polytetrafluoroethylene, polyvinylidene fluoride, polylactic acid, and polypropylene.

[0020] The polymer separation membrane material is pretreated to obtain a pretreated polymer separation membrane material, specifically including:

[0021] The polymer separation membrane material is rinsed in pure water for 2 hours to remove residual solvents, pore-retaining agents, or surface contaminants, thus obtaining a pretreated polymer separation membrane material.

[0022] Step S103: Contact the side of the pretreated polymer separation membrane material to be modified with the modification solution I to obtain the first modified polymer separation membrane material.

[0023] In the embodiments of this specification, the modified solution I contains an adhesive and a coupling agent, and the adhesive and the coupling agent are dissolved in a first buffer solution to obtain the modified solution I.

[0024] In the embodiments described in this specification, the adhesive is one or more of dopamine hydrochloride, tannic acid, and epigallocatechin gallate.

[0025] The coupling agent is one or more of 2-aminophenylboronic acid, 2-aminomethylphenylboronic acid, 3-aminophenylboronic acid, 3-aminomethylphenylboronic acid, 4-aminophenylboronic acid, and 4-aminomethylphenylboronic acid;

[0026] The first buffer solution is a tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

[0027] In the embodiments described in this specification, the concentration of the adhesive is 1~3 g / L;

[0028] The concentration of the coupling agent is 2-4 g / L;

[0029] The first buffer solution has a pH of 8.5 and a concentration of 50 mM.

[0030] In the embodiments of this specification, the step of contacting the pretreated polymer separation membrane material to be modified with the modification solution I to obtain the first modified polymer separation membrane material specifically includes:

[0031] The pretreated polymer separation membrane material to be modified is brought into contact with the modification solution I for 30-60 minutes, so that the adhesive and the coupling agent are loaded on the pretreated polymer separation membrane material to be modified, thereby obtaining the first modified polymer separation membrane material.

[0032] The adhesive exhibits a self-polymerization effect, providing an adhesive layer through this effect. This layer is firmly fixed to the surface of the pretreated polymer separation membrane material via the synergistic action of multiple hydrogen bonds, van der Waals forces, and π-π stacking. This operation is unaffected by the form of the separation membrane material and is applicable to flat sheet membranes, hollow fiber membranes, and tubular membranes. There are no restrictions on the shape, morphology, or flatness of the membrane surface to be modified, thus achieving conformal bonding. The bond between the adhesive layer and the polymer separation membrane material is based on physical interactions, without chemical bonding. Therefore, the introduction of the adhesive layer is also unaffected by the type of polymer constituting the separation membrane material.

[0033] Step S105: After the side of the polymer separation membrane material to be modified is brought into contact with the modification solution II, it is rinsed to complete the conformal hydrophilic modification of the polymer separation membrane material.

[0034] In the embodiments described in this specification, the modified solution II contains a hydrophilic agent, which is dissolved in a second buffer solution to obtain the modified solution II.

[0035] In the embodiments of this specification, the hydrophilic agent is a water-soluble polysaccharide containing ortho- or meta-dihydroxyl groups, and the concentration of the hydrophilic agent is 2-4 g / L;

[0036] The second buffer solution is a sodium carbonate-sodium bicarbonate buffer solution with a pH of 10.0 and a concentration of 100 mM.

[0037] In the embodiments of this specification, the hydrophilic agent is one or more of glucomannan, dextran, polydextrose, galactooligosaccharide, and fructooligosaccharide.

[0038] In the embodiments of this specification, the step of contacting the side of the polymer separation membrane material to be modified with modification solution II, followed by rinsing to complete the conformal hydrophilic modification of the polymer separation membrane material, specifically includes:

[0039] The modified side of the polymer separation membrane material is brought into contact with the modification solution II for 3-5 minutes, and then rinsed with pure water 3 times to complete the conformal hydrophilic modification of the polymer separation membrane material.

[0040] During the self-polymerization process of the adhesive to form an adhesive layer, the polyphenol structure contained therein can undergo Michael addition or Schiff base reaction with the primary amine group in the coupling agent under weakly alkaline conditions to form covalent bonds; the phenylboronic acid unit in the coupling agent can undergo borate esterification reaction with the ortho- or meta-dihydroxy group in the hydrophilic agent under alkaline conditions to form covalent bonds; the above two chemical reactions enable the hydrophilic agent to be stably loaded on the surface of the polymer separation membrane material, overcoming the drawback of easy loss of hydrophilic agent in the prior art.

[0041] Since the hydrophilic agent is a water-soluble polysaccharide, it is electrically neutral and does not interact electrostatically with the chemical components in the fluid. At the same time, when it is loaded on the membrane surface, it will physically shield the charge that the membrane substrate may carry, further reducing the deposition of pollutants through electrostatic attraction.

[0042] Furthermore, since water-soluble polysaccharides contain a large number of hydrophilic polar hydroxyl groups, they can form a hydration layer on the surface of polymer separation membrane materials, reducing the hydrophobic interaction between pollutants and membrane substrates and significantly inhibiting membrane fouling.

[0043] To further illustrate the present invention, the following detailed description of the conformal hydrophilic modification method for polymer separation membrane materials provided by the present invention is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0044] Example 1

[0045] The steps of the conformal hydrophilic modification method for the polymer separation membrane material in this embodiment are as follows:

[0046] (1) Membrane material pretreatment: The polysulfone flat sheet membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0047] (2) Preparation of modified solution I: Tannic acid and 4-aminophenylboronic acid were dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution with pH 8.5 and concentration of 50 mM, wherein the concentration of tannic acid was 1 g / L and the concentration of 4-aminophenylboronic acid was 2 g / L, to obtain modified solution I;

[0048] (3) Preparation of modified solution II: Dissolve dextran in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of dextran is 2 g / L, to obtain modified solution II;

[0049] (4) The polysulfone flat sheet membrane to be modified after step (1) is contacted with the modification solution I for 45 min, and then the membrane material is rinsed with pure water to complete the loading of tannic acid and 4-aminophenylboronic acid on the polysulfone flat sheet membrane to be modified.

[0050] (5) The polysulfone sheet membrane to be modified after step (4) is contacted with the modification solution II for 4 min, and then the membrane material is rinsed with pure water to complete the conformal hydrophilic modification of the polysulfone sheet membrane.

[0051] Example 2

[0052] The steps of the conformal hydrophilic modification method for the polymer separation membrane material in this embodiment are as follows:

[0053] (1) Membrane material pretreatment: The polyethersulfone flat sheet membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0054] (2) Preparation of modified solution I: Dopamine hydrochloride and 4-aminomethylphenylboronic acid were dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution at pH 8.5, wherein the concentration of dopamine hydrochloride was 2 g / L and the concentration of 4-aminomethylphenylboronic acid was 3 g / L, to obtain modified solution I;

[0055] (3) Preparation of modified solution II: Dissolve glucomannan in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of glucomannan is 3 g / L, to obtain modified solution II;

[0056] (4) The polyethersulfone flat sheet membrane to be modified after step (1) is contacted with the modification solution I for 60 min, and then the membrane material is rinsed with pure water to complete the loading of dopamine hydrochloride and 4-aminomethylphenylboronic acid on the polyethersulfone flat sheet membrane to be modified.

[0057] (5) The polyethersulfone flat sheet membrane to be modified after step (4) is brought into contact with the modification solution II for 5 min, and then the membrane material is rinsed with pure water to complete the conformal hydrophilic modification of the polyethersulfone flat sheet membrane.

[0058] Example 3

[0059] The steps of the conformal hydrophilic modification method for the polymer separation membrane material in this embodiment are as follows:

[0060] (1) Membrane material pretreatment: The polytetrafluoroethylene tubular membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0061] (2) Preparation of modified solution I: Tannic acid and 3-aminophenylboronic acid were dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution with pH 8.5 and concentration of 50 mM, wherein the concentration of tannic acid was 2 g / L and the concentration of 3-aminophenylboronic acid was 3 g / L, to obtain modified solution I;

[0062] (3) Preparation of modified solution II: dissolve polydextrose in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of glucomannan is 3 g / L, to obtain modified solution II;

[0063] (4) The polytetrafluoroethylene tubular membrane material to be modified after step (1) is contacted with the modification solution I for 60 min, and then the membrane material is rinsed with pure water to complete the loading of tannic acid and 3-aminophenylboronic acid on the polytetrafluoroethylene tubular membrane material to be modified.

[0064] (5) The polytetrafluoroethylene tubular membrane material to be modified after step (4) is brought into contact with the modification solution II for 5 minutes, and then the membrane material is rinsed with pure water to complete the conformal hydrophilic modification of the polytetrafluoroethylene tubular membrane material.

[0065] Example 4

[0066] The steps of the conformal hydrophilic modification method for the polymer separation membrane material in this embodiment are as follows:

[0067] (1) Membrane material pretreatment: The polyvinylidene fluoride hollow fiber membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0068] (2) Preparation of modified solution I: Epigallocatechin gallate and 3-aminomethylphenylboronic acid were dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution at pH 8.5, wherein the concentration of epigallocatechin gallate was 3 g / L and the concentration of 3-aminomethylphenylboronic acid was 4 g / L, to obtain modified solution I;

[0069] (3) Preparation of modified solution II: Dissolve galactooligosaccharides in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of galactooligosaccharides is 4 g / L, to obtain modified solution II;

[0070] (4) The polyvinylidene fluoride hollow fiber membrane material to be modified after step (1) is contacted with the modification solution I for 30 min, and then the membrane material is rinsed with pure water to complete the loading of epigallocatechin gallate and 3-aminomethylphenylboronic acid on the polyvinylidene fluoride hollow fiber membrane material to be modified.

[0071] (5) The polyvinylidene fluoride hollow fiber membrane material to be modified after step (4) is contacted with the modification solution II for 3 min, and then the membrane material is rinsed with pure water to complete the conformal hydrophilic modification of the polyvinylidene fluoride hollow fiber membrane material.

[0072] Example 5

[0073] The steps of the conformal hydrophilic modification method for the polymer separation membrane material in this embodiment are as follows:

[0074] (1) Membrane material pretreatment: The polylactic acid flat sheet membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0075] (2) Preparation of modified solution I: Epigallocatechin gallate and 2-aminophenylboronic acid were dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution with a pH of 8.5, wherein the concentration of epigallocatechin gallate was 2 g / L and the concentration of 2-aminophenylboronic acid was 3 g / L, to obtain modified solution I;

[0076] (3) Preparation of modified solution II: Dissolve oligofructose in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of oligofructose is 3 g / L, to obtain modified solution II;

[0077] (4) The polylactic acid sheet membrane to be modified after step (1) is contacted with the modification solution I for 60 min, and then the membrane material is rinsed with pure water to complete the loading of epigallocatechin gallate and 2-aminophenylboronic acid on the polylactic acid sheet membrane to be modified.

[0078] (5) The polylactic acid sheet membrane to be modified after step (4) is brought into contact with the modification solution II for 5 min, and then the membrane material is rinsed with pure water to complete the conformal hydrophilic modification of the polylactic acid sheet membrane.

[0079] Example 6

[0080] The steps of the conformal hydrophilic modification method for the polymer separation membrane material in this embodiment are as follows:

[0081] (1) Membrane material pretreatment: The polypropylene hollow fiber membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0082] (2) Preparation of modified solution I: Dopamine hydrochloride and 2-aminomethylphenylboronic acid were dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution at pH 8.5, wherein the concentration of dopamine hydrochloride was 2 g / L and the concentration of 2-aminomethylphenylboronic acid was 3 g / L, to obtain modified solution I;

[0083] (3) Preparation of modified solution II: Dissolve glucomannan in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of glucomannan is 3 g / L, to obtain modified solution II;

[0084] (4) The polypropylene hollow fiber membrane material to be modified after step (1) is contacted with the modification solution I for 60 min, and then the membrane material is rinsed with pure water to complete the loading of dopamine hydrochloride and 2-aminomethylphenylboronic acid on the polypropylene hollow fiber membrane material to be modified.

[0085] (5) The polypropylene hollow fiber membrane material to be modified after step (4) is brought into contact with the modification solution II for 5 minutes, and then the membrane material is rinsed with pure water to complete the conformal hydrophilic modification of the polypropylene hollow fiber membrane material.

[0086] Comparative Example 1

[0087] Comparative Example 1 uses the case where modified solution I does not contain any adhesive as a reference. The operating steps are as follows:

[0088] (1) Membrane material pretreatment: The polyethersulfone flat sheet membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0089] (2) Preparation of modified solution I: 4-aminomethylphenylboronic acid was dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution at pH 8.5, wherein the concentration of 4-aminomethylphenylboronic acid was 3 g / L, to obtain modified solution I;

[0090] (3) Preparation of modified solution II: Dissolve glucomannan in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of glucomannan is 3 g / L, to obtain modified solution II;

[0091] (4) The polyethersulfone flat sheet membrane to be modified after step (1) is contacted with modification solution I for 60 min, and then the membrane material is rinsed with pure water.

[0092] (5) The polyethersulfone flat sheet membrane to be modified after step (4) is brought into contact with the modification solution II for 5 min, and then the membrane material is rinsed with pure water to complete the modification of the polyethersulfone flat sheet membrane material.

[0093] Comparative Example 2

[0094] Comparative Example 2 uses the case where modified solution I does not contain a coupling agent. The operating steps are as follows:

[0095] (1) Membrane material pretreatment: The polyethersulfone flat sheet membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0096] (2) Preparation of modified solution I: Dopamine hydrochloride was dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution at pH 8.5, wherein the concentration of dopamine hydrochloride was 2 g / L, to obtain modified solution I;

[0097] (3) Preparation of modified solution II: Dissolve glucomannan in a sodium carbonate-sodium bicarbonate buffer solution with pH 10 and a concentration of 100 mM, wherein the concentration of glucomannan is 3 g / L, to obtain modified solution II;

[0098] (4) The polyethersulfone flat sheet membrane to be modified after step (1) is contacted with the modification solution I for 60 min, and then the membrane material is rinsed with pure water to complete the loading of dopamine hydrochloride on the polyethersulfone flat sheet membrane to be modified.

[0099] (5) The polyethersulfone flat sheet membrane to be modified after step (4) is brought into contact with the modification solution II for 5 min, and then the membrane material is rinsed with pure water to complete the modification of the polyethersulfone flat sheet membrane material.

[0100] Comparative Example 3

[0101] Comparative Example 3 uses the case without treatment by modified solution II as an example. The operation steps are as follows:

[0102] (1) Membrane material pretreatment: The polyethersulfone flat sheet membrane material is thoroughly rinsed and soaked in pure water to wash out residual solvent, pore-retaining agent or surface dirt;

[0103] (2) Preparation of modified solution I: Dopamine hydrochloride and 4-aminomethylphenylboronic acid were dissolved in a 50 mM tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution at pH 8.5, wherein the concentration of dopamine hydrochloride was 2 g / L and the concentration of 4-aminomethylphenylboronic acid was 3 g / L, to obtain modified solution I;

[0104] (3) The polyethersulfone flat sheet membrane to be modified after step (1) is contacted with the modification solution I for 60 min, and then the membrane material is rinsed with pure water to complete the conformal hydrophilic modification of the polyethersulfone flat sheet membrane material.

[0105] Test Example 1

[0106] The polymer membrane materials obtained in Examples 1-6 and Comparative Examples 1-3 were used as samples for water contact angle testing. The testing methods are as follows:

[0107] The contact angle of the modified side of the membrane material was determined using the static drop method. A droplet was carefully added to the fully dried membrane material, and the contact angle value was recorded after 2 seconds. Five different locations were tested for each sample, and the average value was taken as the final result. The measured water contact angle data are shown in Table 1. A smaller contact angle indicates better hydrophilicity of the tested surface.

[0108] Test Example 2

[0109] The polymer membrane materials obtained in Examples 1-6 and Comparative Examples 1-3 were used as samples for simulated static adsorption tests of pollutants. The test methods are as follows:

[0110] Bovine serum albumin (BSA) was used as a simulated pollutant and dissolved in phosphate buffer at a concentration of 500 ppm. 50 mL of this solution was taken and brought into contact with the test surface of the polymer membrane material, and allowed to stand at 25°C for 48 h. The BSA concentration in the solution before and after standing was given based on the intensity of the UV absorption peak at 280 nm. The adsorption capacity of BSA on the membrane surface, Q (mg / m³), was calculated. 2 ) is calculated using the following formula:

[0111] Q = (C0-C)V / A

[0112] Where A(m) 2 The adsorption area is V(L), the volume of bovine serum albumin solution is V(L), and C0 and C(mg / L) are the concentrations of bovine serum albumin in the solution before and after standing, respectively. Each sample was measured three times in parallel according to the above method, and the average value was taken as the final result.

[0113] The measured data on bovine serum albumin adsorption on the membrane surface are shown in Table 1. The smaller the adsorption value, the better the hydrophilicity of the test surface, and the less likely pollutants are to adhere.

[0114] Table 1. Water contact angle and bovine serum albumin adsorption data of polymer separation membrane materials

[0115]

[0116] As shown in Table 1, after conformal hydrophilic modification, the contact angle of the polymer separation membrane material is 21–32°, falling within the category of hydrophilic membrane materials. Compared to the unmodified material, the contact angle of the modified membrane material decreased by 47–95°, demonstrating the effectiveness of the embodiments in improving the hydrophilicity of the membrane material. After conformal hydrophilic modification, the adsorption capacity of bovine serum albumin on the surface of the polymer separation membrane material is 218–316 mg / m³. 2Compared to before modification, the concentration decreased by 62% to 78%, indicating that by implementing the embodiments provided in this specification, the hydrophilicity of the membrane surface is improved, which can effectively reduce the adhesion of pollutants.

[0117] Compared to the polyethersulfone sheet membrane material prepared in Comparative Example 1 without an adhesive in modified solution I, Example 2 exhibits a lower water contact angle, less bovine serum albumin adsorption, and better hydrophilicity, highlighting the importance of the adhesive. Compared to the polyethersulfone sheet membrane material prepared in Comparative Example 2 without a coupling agent in modified solution I, Example 2 exhibits a lower water contact angle, less bovine serum albumin adsorption, and better hydrophilicity, highlighting the importance of the coupling agent. Compared to the polyethersulfone sheet membrane material prepared in Comparative Example 3 without treatment with modified solution II, Example 2 exhibits a lower water contact angle, less bovine serum albumin adsorption, and better hydrophilicity, highlighting the importance of hydrophilic agent treatment.

[0118] As can be seen from the above embodiments and comparative examples, the present technical solution can significantly improve the hydrophilicity of polymer separation membrane materials, and the adhesive, coupling agent and hydrophilic agent all play important roles.

[0119] This specification provides a conformal hydrophilic modification method for polymer separation membrane materials. Through a chemical reaction, a hydrophilic agent is stably loaded onto the surface of the polymer separation membrane material, overcoming the drawback of easy hydrophilic agent loss in existing technologies. Simultaneously, the modification process is unrestricted in terms of the shape, morphology, and flatness of the membrane surface to be modified, achieving conformal modification. Furthermore, the hydrophilic agent is electrically neutral, which can reduce the deposition of pollutants caused by electrostatic attraction. The technical solution proposed in this invention is simple to operate and easily scaled up industrially.

[0120] The above description is merely a preferred embodiment of the present invention and is not intended to limit the implementation. It should be noted that those skilled in the art can make other variations or modifications without departing from the principles of the present invention, and any obvious variations or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for conformal hydrophilic modification of a polymer separation membrane material, characterized in that, The conformal hydrophilic modification method includes: The polymer separation membrane material is pretreated to obtain a pretreated polymer separation membrane material; The pretreated polymer separation membrane material to be modified is brought into contact with the modification solution I to obtain the first modified polymer separation membrane material; After the side of the polymer separation membrane material to be modified is brought into contact with the modification solution II, it is rinsed to complete the conformal hydrophilic modification of the polymer separation membrane material.

2. The conformal hydrophilic modification method for a polymer separation membrane material as described in claim 1, characterized in that, The modified solution I contains an adhesive and a coupling agent. The adhesive and the coupling agent are dissolved in a first buffer solution to obtain the modified solution I.

3. The conformal hydrophilic modification method for a polymer separation membrane material as described in claim 2, characterized in that, The adhesive is one or more of dopamine hydrochloride, tannic acid, and epigallocatechin gallate; The coupling agent is one or more of 2-aminophenylboronic acid, 2-aminomethylphenylboronic acid, 3-aminophenylboronic acid, 3-aminomethylphenylboronic acid, 4-aminophenylboronic acid, and 4-aminomethylphenylboronic acid; The first buffer solution is a tris(hydroxymethyl)aminomethane-hydrochloric acid buffer solution.

4. The conformal hydrophilic modification method for a polymer separation membrane material as described in claim 2, characterized in that, The concentration of the adhesive is 1~3 g / L; The concentration of the coupling agent is 2-4 g / L; The first buffer solution has a pH of 8.5 and a concentration of 50 mM.

5. The conformal hydrophilic modification method for a polymer separation membrane material as described in claim 1, characterized in that, The modified solution II contains a hydrophilic agent, which is dissolved in a second buffer solution to obtain the modified solution II.

6. The conformal hydrophilic modification method for a polymer separation membrane material as described in claim 5, characterized in that, The hydrophilic agent is a water-soluble polysaccharide containing ortho- or meta-dihydroxyl groups, and the concentration of the hydrophilic agent is 2-4 g / L; The second buffer solution is a sodium carbonate-sodium bicarbonate buffer solution with a pH of 10.0 and a concentration of 100 mM.

7. The conformal hydrophilic modification method for a polymer separation membrane material as described in claim 6, characterized in that, The hydrophilic agent is one or more of glucomannan, glucan, polydextrose, galactooligosaccharide, and fructooligosaccharide.

8. The conformal hydrophilic modification method for a polymer separation membrane material as described in claim 2, characterized in that, The step of contacting the pretreated polymer separation membrane material to be modified with modification solution I to obtain the first modified polymer separation membrane material specifically includes: The pretreated polymer separation membrane material to be modified is brought into contact with the modification solution I for 30-60 minutes, so that the adhesive and the coupling agent are loaded on the pretreated polymer separation membrane material to be modified, thereby obtaining the first modified polymer separation membrane material.

9. The conformal hydrophilic modification method as described in claim 5, characterized in that, The process of contacting the side of the polymer separation membrane material to be modified with modification solution II, followed by rinsing, to complete the conformal hydrophilic modification of the polymer separation membrane material specifically includes: The modified side of the polymer separation membrane material is brought into contact with the modification solution II for 3-5 minutes, and then rinsed with pure water 3 times to complete the conformal hydrophilic modification of the polymer separation membrane material.

10. The conformal hydrophilic modification method as described in claim 1, characterized in that, The polymer separation membrane material includes: flat sheet membrane, hollow fiber membrane, and tubular membrane; The polymer separation membrane material comprises: polysulfone, polyethersulfone, polytetrafluoroethylene, polyvinylidene fluoride, polylactic acid, and polypropylene.

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