Hydrophilic ultrafiltration membrane and preparation method thereof

Abstract

The invention relates to the technical field of membrane separation, in particular to a hydrophilic ultrafiltration membrane and a preparation method thereof.The hydrophilic ultrafiltration membrane is prepared from membrane liquid containing a component A and a component B; the component A comprises DMAC (dimethylacetamide), NMP (N-Methyl Pyrrolidone), PES (Polyether Sulfonate), PVP-k30, a moisturizing solubilizer, a hydrophilic modifier, a humectant, a stabilizer and a Tween type emulsifier; the component B is prepared from the following components in parts by weight: DMAC, NMP, PVDF, a moisturizing solubilizer, PVP-k30 and a Tween type emulsifier. PEG and PVP are adopted as additives, the relative molecular mass of the additives is regulated and controlled, the polyethersulfone / nanocellulose ultrafiltration membrane is prepared, the performance of the composite ultrafiltration membrane is compared, and the PES ultrafiltration membrane with high flux and strong pollution resistance is prepared by a system. The component A containing PEG and PVP and the component B containing PVDF and PEG are prepared respectively, and then the two components are mixed, so that the adhesive force of the membrane can be improved, and the membrane is smoother.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane separation, in particular to a hydrophilic ultrafiltration membrane and a preparation method thereof. Background Art

[0002] Membrane separation technology is an emerging separation technology with low cost, high efficiency and environmental friendliness. It is widely used in many fields such as water resource development and utilization, food and medicine, healthcare and electronics industry.

[0003] Polyethersulfone (PES) is a common material used in the preparation of bioseparation membranes, exhibiting excellent thermal stability, mechanical properties, processing capabilities, and biocompatibility. However, PES ultrafiltration membranes currently available on the market are prone to contamination and clogging during use, requiring high pretreatment requirements. Long-term contamination and clogging can affect the lifespan of the ultrafiltration membrane. Furthermore, due to the small pore size, which is susceptible to contamination and clogging, frequent cleaning is required during use. To ensure the proper function of the ultrafiltration membrane, it is typically cleaned once a month. This cleaning process is difficult and requires consideration of factors such as pressure, temperature, pH, and chemical reagents.

[0004] Therefore, we propose a hydrophilic ultrafiltration membrane and a preparation method thereof to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a hydrophilic ultrafiltration membrane and a preparation method thereof.

[0006] A hydrophilic ultrafiltration membrane is prepared from a membrane solution comprising component A and component B; The A component includes the following components in parts by weight: DMAC 50-200 parts, NMP 50-200 parts, PES 30-100 parts, PVP-k30 10-50 parts, moisturizing solubilizer 10-50 parts, hydrophilic modifier 0-10 parts, humectant 0-20 parts, stabilizer 0-15 parts, Tween emulsifier 0-15 parts; The B component includes the following components in parts by weight: DMAC 10-50 parts, NMP 10-50 parts, PVDF 10-30 parts, moisturizing solubilizer 10-50 parts, PVP-k30 5-15 parts, Tween emulsifier 0-15 parts.

[0007] Preferably, the moisturizing solubilizing agent is PEG with a molecular weight of 200 to 8000.

[0008] Preferably, the moisturizing agent is one or more of glycerol, ethylene glycol and sorbitol.

[0009] Preferably, the stabilizer is TS-01.

[0010] Preferably, the Tween-type emulsifier is polysorbate-20.

[0011] Preferably, the hydrophilic modifier is one or both of PSK04 and PSK05.

[0012] Preferably, the purity of the DMAC is not less than 99%, and the concentration of the NMP is not less than 99%.

[0013] A method for preparing a hydrophilic ultrafiltration membrane comprises the following steps: S1. Preparation of membrane solution: S1-1, adding 50 to 200 parts by weight of DMAC and 50 to 200 parts by weight of NMP into a container at room temperature, stirring evenly and heating; S1-2, sequentially adding 30-100 parts by weight of PES, 10-50 parts by weight of PVP-k30, 10-50 parts by weight of a moisturizing solubilizer, 0-10 parts by weight of a hydrophilic modifier, 0-20 parts by weight of a humectant, 0-15 parts by weight of a stabilizer, and 0-15 parts by weight of a Tween-type emulsifier, and stirring for 2-10 hours to obtain component A; S1-3, adding 10 to 50 parts by weight of DMAC and 10 to 50 parts by weight of NMP into a container at room temperature, stirring evenly and heating; S1-4, sequentially adding 10 to 30 parts by weight of PVDF, 10 to 50 parts by weight of a moisturizing solubilizer, 5 to 15 parts by weight of PVP-k30, and 0 to 15 parts by weight of a Tween emulsifier, and stirring for 2 to 10 hours to obtain component B; S1-5, mixing component A and component B, and letting them stand for 5 to 20 hours to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: Use a membrane scraping device to scrape the membrane in a water bath to obtain an ultrafiltration membrane.

[0014] Preferably, in steps S1-2, S1-4 and S1-5, the stirring temperature is between 20 and 30° C., and the rotation speed is between 20 and 50 rpm.

[0015] Preferably, in step S2, the membrane liquid is stirred at 50-80° C. for 10-15 hours, allowed to stand until it reaches room temperature, added to a membrane scraping machine, and membrane scraped in a water bath at 50-80° C.

[0016] The beneficial effects of the present invention are: 1. Using PEG and PVP as additives, regulating the relative molecular weight of the additives, the polyethersulfone / nanocellulose ultrafiltration membrane is prepared. The membrane has high initial flux, strong pollution resistance, strong durability, and can ensure the retention rate at high membrane flux, and the ultrafiltration membrane has a long service life.

[0017] 2. Prepare component A containing PEG and PVP and component B containing PVDF and PEG separately, and then mix the two to improve the adhesion of the membrane. Add hydrophilic modifiers PSK04 and PSK05 to increase the bubble point pressure of the membrane liquid, further improve the adhesion of the membrane, and make the membrane smoother. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an electron microscope image of the ultrafiltration membrane prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further explained below with reference to specific embodiments. Example 1

[0020] A method for preparing a hydrophilic ultrafiltration membrane comprises the following steps: S1. Preparation of membrane solution: S1-1. Pour 150 g of DMAC and 110 g of NMP into a beaker at room temperature, stir well, and heat; S1-2, add PES 70g, PVP-k30 20g, PEG400 25g, PSK04 4g, PSK05 4g, glycerol 8g, TS-01 6g, and polysorbate 20 6g in sequence, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30°C and a speed of 30 rpm to obtain component A; S1-3, pour 35g of DMAC and 28g of NMP into a beaker at room temperature, stir well and heat; S1-4, sequentially add PVDF 17 g, PEG400 7 g, PEG4000 7 g, PVP-k30 7 g, and polysorbate 20 1 g, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30° C. and a speed of 30 rpm to obtain component B; S1-5, mixing components A and B, stirring at a temperature between 20 and 30°C and a speed of 30 rpm for 6 hours, and then letting it stand for 12 hours to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: The membrane liquid was stirred at 60°C for 12 hours, allowed to stand until it reached room temperature, added to a membrane scraping machine, and scraped in a water bath at 60°C to obtain an ultrafiltration membrane.

[0021] Wherein, the purity of DMAC is not less than 99%, and the concentration of NMP is not less than 99%. Example 2

[0022] A method for preparing a hydrophilic ultrafiltration membrane comprises the following steps: S1. Preparation of membrane solution: S1-1. Pour 136 g of DMAC and 120 g of NMP into a beaker at room temperature, stir well, and heat; S1-2, add 64 g of PES, 27 g of PVP-k30, 21 g of PEG400, 4 g of PSK04, 4 g of PSK05, 8 g of glycerol, 6 g of TS-01, and 6 g of polysorbate 20 in sequence, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30° C. and a speed of 30 rpm to obtain component A; S1-3, pour 33.5g of DMAC and 30g of NMP into a beaker at room temperature, stir well and heat; S1-4, sequentially add PVDF 17 g, PEG400 7 g, PEG4000 7 g, PVP-k30 7 g, and polysorbate 20 1 g, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30° C. and a speed of 30 rpm to obtain component B; S1-5, mixing components A and B, stirring at a temperature between 20 and 30°C and a speed of 30 rpm for 6 hours, and then letting it stand for 12 hours to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: The membrane liquid was stirred at 60°C for 12 hours, allowed to stand until it reached room temperature, added to a membrane scraping machine, and scraped in a water bath at 60°C to obtain an ultrafiltration membrane.

[0023] Wherein, the purity of DMAC is not less than 99%, and the concentration of NMP is not less than 99%. Example 3

[0024] A method for preparing a hydrophilic ultrafiltration membrane comprises the following steps: S1. Preparation of membrane solution: S1-1. Pour 125 g of DMAC and 130 g of NMP into a beaker at room temperature, stir well, and heat; S1-2, add PES 60g, PVP-k30 30g, PEG400 21g, PSK04 4g, PSK05 4g, glycerol 8g, TS-01 6g, and polysorbate 20 6g in sequence, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30°C and a speed of 30 rpm to obtain component A; S1-3, pour 33.5g of DMAC and 30g of NMP into a beaker at room temperature, stir well and heat; S1-4, sequentially add PVDF 15g, PEG400 8g, PEG4000 8g, PVP-k30 7g, and polysorbate 201g, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30°C and a speed of 30 rpm to obtain component B; S1-5, mixing components A and B, stirring at a temperature between 20 and 30°C and a speed of 30 rpm for 6 hours, and then letting it stand for 12 hours to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: The membrane liquid was stirred at 60°C for 12 hours, allowed to stand until it reached room temperature, added to a membrane scraping machine, and scraped in a water bath at 60°C to obtain an ultrafiltration membrane.

[0025] Wherein, the purity of DMAC is not less than 99%, and the concentration of NMP is not less than 99%. Example 4

[0026] A method for preparing a hydrophilic ultrafiltration membrane comprises the following steps: S1. Preparation of membrane solution: S1-1. Pour 140 g of DMAC and 120 g of NMP into a beaker at room temperature, stir well, and heat; S1-2, add 64 g of PES, 27 g of PVP-k30, 21 g of PEG400, 4 g of PSK04, 4 g of PSK05, 8 g of glycerol, 6 g of TS-01, and 6 g of polysorbate 20 in sequence, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30° C. and a speed of 30 rpm to obtain component A; S1-3, pour 33.5g of DMAC and 30g of NMP into a beaker at room temperature, stir well and heat; S1-4, sequentially add PVDF 20 g, PEG400 10 g, PEG4000 5 g, PVP-k30 7 g, and polysorbate 20 1 g, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30° C. and a speed of 30 rpm to obtain component B; S1-5, mixing components A and B, stirring at a temperature between 20 and 30°C and a speed of 30 rpm for 6 hours, and then letting it stand for 12 hours to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: The membrane liquid was stirred at 60°C for 12 hours, allowed to stand until it reached room temperature, added to a membrane scraping machine, and scraped in a water bath at 60°C to obtain an ultrafiltration membrane.

[0027] Wherein, the purity of DMAC is not less than 99%, and the concentration of NMP is not less than 99%.

[0028] Comparative Example 1: The preparation method of the PES membrane comprises the following steps: S1. Preparation of membrane solution: S1-1. Pour 136 g of DMAC and 120 g of NMP into a beaker at room temperature, stir well, and heat; S1-2, add PES 64g, PEG400 21g, PSK04 4g, PSK05 4g, glycerol 8g, TS-01 6g, and polysorbate 20 6g in sequence, and stir with an adjustable-speed stirrer for 6 hours at a temperature between 20 and 30°C and a speed of 30 rpm to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: The membrane liquid was stirred at 60°C for 12 hours, allowed to stand until it reached room temperature, added to a membrane scraping machine, and scraped in a water bath at 60°C to obtain an ultrafiltration membrane.

[0029] Wherein, the purity of DMAC is not less than 99%, and the concentration of NMP is not less than 99%.

[0030] Comparative Example 2: S1. Preparation of membrane solution: S1-1. Pour 136 g of DMAC and 120 g of NMP into a beaker at room temperature, stir well, and heat; S1-2, add PES 64g, PVP-k30 27g, PEG400 21g, PSK04 4g, PSK05 4g, glycerol 8g, TS-01 6g, polysorbate-20 6g in sequence, and stir with an adjustable speed stirrer for 6 hours at a temperature between 20 and 30°C and a speed of 30 rpm to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: The membrane liquid was stirred at 60°C for 12 hours, allowed to stand until it reached room temperature, added to a membrane scraping machine, and scraped in a water bath at 60°C to obtain an ultrafiltration membrane.

[0031] Wherein, the purity of DMAC is not less than 99%, and the concentration of NMP is not less than 99%.

[0032] The hydrophilicity, adhesion and pollution resistance of the ultrafiltration membranes prepared according to the methods of Examples 1 to 3 and Comparative Examples 1 to 2 were tested.

[0033] The hydrophilicity is characterized by the contact angle of the membrane surface. The contact angle of the membrane surface is measured using the standard drop method, with ultrapure water as the standard liquid and a drop volume of 5 μL. When ultrapure water is dropped on the membrane surface, it is immediately analyzed using an optical contact angle meter.

[0034] The anti-fouling performance was characterized by membrane flux, and the membrane flux was measured at the initial stage and after 90 days, 180 days, 270 days, 360 days, 720 days, and 1080 days of use.

[0035] Adhesion was tested by the tape tear method, and retention was the retention of bovine serum albumin.

[0036] The test results are as follows:

[0037] Compared with the comparative example, the ultrafiltration membrane in the embodiment has better adhesion, the initial membrane flux can be increased by up to 46%, the membrane flux after 1080 days of continuous operation can be increased by up to 97%, and the retention rate can be guaranteed at high membrane flux.

[0038] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A hydrophilic ultrafiltration membrane, characterized in that Prepared from a membrane solution comprising component A and component B; The A component includes the following components in parts by weight: DMAC 50-200 parts, NMP 50-200 parts, PES 30-100 parts, PVP-k30 10-50 parts, moisturizing solubilizer 10-50 parts, hydrophilic modifier 0-10 parts, humectant 0-20 parts, stabilizer 0-15 parts, Tween emulsifier 0-15 parts; The B component includes the following components in parts by weight: DMAC 10-50 parts, NMP 10-50 parts, PVDF 10-30 parts, moisturizing solubilizer 10-50 parts, PVP-k30 5-15 parts, Tween emulsifier 0-15 parts.

2. A hydrophilic ultrafiltration membrane according to claim 1, characterized in that: The moisturizing solubilizing agent is PEG with a molecular weight of 200 to 8000.

3. The hydrophilic ultrafiltration membrane according to claim 1, characterized in that The moisturizing agent is one or more of glycerol, ethylene glycol and sorbitol.

4. The hydrophilic ultrafiltration membrane according to claim 1, characterized in that: The stabilizer is TS-01.

5. The hydrophilic ultrafiltration membrane according to claim 1, characterized in that: The Tween emulsifier is polysorbate-20.

6. The hydrophilic ultrafiltration membrane according to claim 1, characterized in that: The hydrophilic modifier is one or both of PSK04 and PSK05.

7. The hydrophilic ultrafiltration membrane according to claim 1, characterized in that: The purity of the DMAC is not less than 99%, and the concentration of the NMP is not less than 99%.

8. A method for preparing a hydrophilic ultrafiltration membrane, characterized in that: The following steps are involved: S1. Preparation of membrane solution: S1-1, adding 50 to 200 parts by weight of DMAC and 50 to 200 parts by weight of NMP into a container at room temperature, stirring evenly and heating; S1-2, sequentially adding 30-100 parts by weight of PES, 10-50 parts by weight of PVP-k30, 10-50 parts by weight of a moisturizing solubilizer, 0-10 parts by weight of a hydrophilic modifier, 0-20 parts by weight of a humectant, 0-15 parts by weight of a stabilizer, and 0-15 parts by weight of a Tween-type emulsifier, and stirring for 2-10 hours to obtain component A; S1-3, adding 10 to 50 parts by weight of DMAC and 10 to 50 parts by weight of NMP into a container at room temperature, stirring evenly and heating; S1-4, sequentially adding 10 to 30 parts by weight of PVDF, 10 to 50 parts by weight of a moisturizing solubilizer, 5 to 15 parts by weight of PVP-k30, and 0 to 15 parts by weight of a Tween emulsifier, and stirring for 2 to 10 hours to obtain component B; S1-5, mixing component A and component B, and letting them stand for 5 to 20 hours to obtain a membrane solution; S2. Preparation of ultrafiltration membrane: Use a membrane scraping device to scrape the membrane in a water bath to obtain an ultrafiltration membrane.

9. The method for preparing a hydrophilic ultrafiltration membrane according to claim 8, characterized in that: In steps S1-2, S1-4 and S1-5, the stirring temperature is between 20 and 30°C, and the rotation speed is between 20 and 50 rpm.

10. The method for preparing a hydrophilic ultrafiltration membrane according to claim 8, characterized in that: In step S2, the membrane solution is stirred at 50-80°C for 10-15 hours, allowed to stand until it reaches room temperature, added to a membrane scraping machine, and membrane scraped in a water bath at 50-80°C.

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