Temperature-responsive separation membrane and preparation method therefor

Abstract

A temperature-responsive separation membrane and a preparation method therefor. The temperature-responsive separation membrane comprises the following components in parts by weight: 12-20 parts of a polymer membrane material, 60-85 parts of a polar solvent, 0.5-2 parts of a temperature control reagent, 6-10 parts of a polymer pore-forming agent and 0.5-2 parts of an additive. The preparation process for the membrane is simple, continuous, makes it easy to achieve industrialization, convenient in terms of operation and easy to control, and saves on energy consumption and reduces costs; in addition, the prepared temperature-responsive separation membrane can respond to the temperature of a separation liquid.

Description

A temperature-responsive separation membrane and preparation method thereof Technical Field

[0001] The present invention belongs to the technical field of sewage treatment material processing and preparation, and more specifically, relates to a temperature-responsive separation membrane and a preparation method thereof. Background Art

[0002] PVDF membranes are widely used in water treatment and bioseparation systems due to their excellent performance. However, their hydrophilic nature makes them susceptible to contamination by proteins, polysaccharides, and other substances during use. In recent years, membranes responsive to environmental stimuli, such as temperature, pH, light, and electricity, have attracted research attention. The separation efficiency and filtration performance of temperature-responsive membranes are influenced by the temperature of the feed solution.

[0003] There are two common methods for preparing temperature-responsive membranes. One is blending modification, which is widely used in industrial manufacturing. The other is to synthesize functionalized thermosensitive materials or graft thermosensitive materials onto membrane materials using methods such as plasma treatment and photografting.

[0004] Therefore, it is urgent to propose a new temperature-responsive separation membrane and its preparation method to reduce manufacturing costs and improve hydrophilicity and anti-fouling properties.

[0005] Summary of the Invention

[0006] The present invention addresses the shortcomings of existing technologies and provides a temperature-responsive separation membrane and its preparation method. The preparation process is simple, continuous, and easily industrialized, with convenient and controllable operation, energy savings, and cost reduction. Furthermore, the prepared temperature-responsive separation membrane responds to the temperature of the separation fluid.

[0007] In order to achieve the above-mentioned purpose, the present invention provides a temperature-responsive separation membrane on the one hand, which comprises the following components in parts by weight: 12-20 parts of polymer membrane material, 60-85 parts of polar solvent, 0.5-2 parts of temperature control agent, 6-10 parts of polymer pore-forming agent and 0.5-2 parts of additive.

[0008] According to the present invention, preferably, the temperature-responsive separation membrane comprises the following components in parts by weight: 15-20 parts of polymer membrane material, 65-82 parts of polar solvent, 0.5-1.5 parts of temperature control agent, 7-9 parts of polymer pore-forming agent and 0.5-1.5 parts of additive.

[0009] According to the present invention, preferably, the polymer membrane material is polyvinylidene fluoride and / or polytetrafluoroethylene.

[0010] According to the present invention, preferably, the polar solvent is dimethylacetamide and / or N-methylpyrrolidone.

[0011] According to the present invention, preferably, the temperature control agent is N-isopropylacrylamide.

[0012] According to the present invention, preferably, the polymer pore-forming agent is polyvinyl pyrrolidone with a degree of polymerization of K15-K90, preferably, the polymer pore-forming agent is polyvinyl pyrrolidone PVPK-15 and / or polyvinyl pyrrolidone PVPK-30.

[0013] According to the present invention, preferably, the additive is glycerol and / or cellulose acetate.

[0014] Another aspect of the present invention provides a method for preparing the temperature-responsive separation membrane, the method comprising the following steps:

[0015] S1: mixing and stirring the polar solvent, temperature control agent and polymer pore-forming agent to obtain a mixed solution;

[0016] S2: drying the polymer membrane material to a constant weight to obtain a dry polymer membrane material powder, mixing the powder with the mixed solution and the additives to obtain a casting solution, and sealing and allowing the solution to stand for degassing;

[0017] S3: Scrape the degassed casting liquid onto a non-woven fabric, and after a first preset time, immerse the non-woven fabric coated with the casting liquid in a water coagulation bath for curing to obtain a cured film; after removing the residual solvent on the surface of the cured film, immerse the cured film again in a water coagulation bath for a second preset time, take it out and dry it naturally to obtain the temperature-responsive separation membrane.

[0018] According to the present invention, preferably, in step S1, the stirring time is 7-10 h, and the stirring rate is 100 rpm-150 rpm.

[0019] According to the present invention, preferably, in step S2, the stirring rate is 150 rpm-250 rpm.

[0020] According to the present invention, preferably, step S2 is performed at 15-30°C.

[0021] According to the present invention, preferably, in step S3:

[0022] The thickness of the scraper used for the scraping is 100-2000 μm;

[0023] The first preset time is 15-45s;

[0024] removing the residual solvent on the surface of the cured film by washing with water;

[0025] The second preset time is 24-48 hours.

[0026] According to the present invention, preferably, step S3 is performed at 15-30°C.

[0027] The beneficial effects of the technical solution of the present invention are as follows:

[0028] The present invention adopts a blending modification method, utilizes a solution phase conversion process, uses a polymer membrane material as a matrix, preferably uses N-isopropylacrylamide as a temperature control agent, and prepares a temperature-responsive separation membrane under polar solvent conditions.

[0029] The preparation process of the present invention is simple, continuous, easy to industrialize, convenient to operate and easy to control, saves energy consumption and reduces costs. At the same time, the prepared temperature-responsive separation membrane can respond to the temperature of the separation liquid.

[0030] The temperature-responsive separation membrane of the present invention can be used in a membrane bioreactor.

[0031] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0033] FIG1 shows a SEM image of the surface morphology of a temperature-responsive separation membrane provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0034] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Instead, these embodiments are provided to make the present invention more thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0035] Example 1

[0036] This embodiment provides a temperature-responsive separation membrane, which includes the following components in parts by weight: 18 parts of polyvinylidene fluoride, 70 parts of dimethylacetamide, 1 part of N-isopropylacrylamide, 8 parts of polyvinylpyrrolidone PVPK-15, and 1.5 parts of glycerol.

[0037] The method for preparing the temperature-responsive separation membrane comprises the following steps:

[0038] S1: mixing the dimethylacetamide, N-isopropylacrylamide and polyvinylpyrrolidone PVPK-15 at 150 rpm for 8 hours to obtain a mixed solution;

[0039] S2: drying the polyvinylidene fluoride to a constant weight, removing moisture, obtaining dry polyvinylidene fluoride powder, and mixing the dry polyvinylidene fluoride powder with the mixed solution and glycerol at room temperature and 150 rpm to uniformly dissolve the polyvinylidene fluoride powder, obtaining a casting solution, and sealing and standing at room temperature for degassing;

[0040] S3: The degassed casting liquid is scraped onto the non-woven fabric (the thickness of the scraper is 150 μm). After 15-45 seconds, the non-woven fabric coated with the casting liquid is immersed in a water coagulation bath for curing to obtain a cured film; after removing the residual solvent on the surface of the cured film, the cured film is immersed in a water coagulation bath again for 36 hours, taken out, and naturally dried at room temperature to obtain the temperature-responsive separation membrane, whose surface micromorphology is shown in Figure 1.

[0041] Test Case

[0042] In this test example, the pure water flux performance of the temperature-responsive separation membrane of Example 1 was tested at different temperatures. The results are shown in Table 1.

[0043] Table 1

[0044] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A temperature-responsive separation membrane, characterized in that: The temperature responsive separation membrane comprises the following components in parts by weight: 12-20 parts of polymer membrane material, 60-85 parts of polar solvent, 0.5-2 parts of temperature control agent, 6-10 parts of polymer pore-forming agent and 0.5-2 parts of additive.

2. The temperature-responsive separation membrane according to claim 1, wherein: The temperature responsive separation membrane comprises the following components in parts by weight: 15-20 parts of polymer membrane material, 65-82 parts of polar solvent, 0.5-1.5 parts of temperature control agent, 7-9 parts of polymer pore-forming agent and 0.5-1.5 parts of additive.

3. The temperature-responsive separation membrane according to claim 1 or 2, wherein: The polymer film material is polyvinylidene fluoride and / or polytetrafluoroethylene; The polar solvent is dimethylacetamide and / or N-methylpyrrolidone; The temperature control agent is N-isopropylacrylamide; The polymer pore-forming agent is polyvinyl pyrrolidone with a polymerization degree of K15-K90; The additive is glycerol and / or cellulose acetate.

4. The temperature-responsive separation membrane according to claim 3, wherein: The polymer pore-forming agent is polyvinyl pyrrolidone PVPK-15 and / or polyvinyl pyrrolidone PVPK-30.

5. The method for preparing a temperature-responsive separation membrane according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: S1: mixing and stirring the polar solvent, the temperature control agent and the polymer pore-forming agent to obtain a mixed solution; S2: drying the polymer membrane material to a constant weight to obtain a dry polymer membrane material powder, and mixing and stirring the mixed solution and the additive to obtain a casting solution, and sealing and standing the solution for degassing; S3: Scrape the degassed casting solution onto the non-woven fabric. After a first preset time, The nonwoven fabric with the casting solution is immersed in a water coagulation bath for curing to obtain a cured film; after removing the residual solvent on the surface of the cured film, the cured film is immersed in the water coagulation bath again for a second preset time, taken out and naturally dried to obtain the temperature responsive separation membrane.

6. The method for preparing a temperature-responsive separation membrane according to claim 5, wherein: In step S1, the stirring time is 7-10 hours, and the stirring speed is 100 rpm-150 rpm.

7. The method for preparing a temperature-responsive separation membrane according to claim 5, wherein: In step S2, the stirring rate is 150 rpm-250 rpm.

8. The method for preparing a temperature-responsive separation membrane according to claim 7, wherein: The step S2 is performed at 15-30°C.

9. The method for preparing a temperature-responsive separation membrane according to claim 5, wherein: In step S3: The thickness of the scraper used for the scraping is 100-2000 μm; The first preset time is 15-45s; removing the residual solvent on the surface of the cured film by washing with water; The second preset time is 24-48 hours.

10. The method for preparing a temperature-responsive separation membrane according to claim 9, wherein: The step S3 is performed at 15-30°C.

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