Ceramic-lined polysulfone ultrafiltration membrane and preparation method thereof

Abstract

The invention relates to the technical field of membrane separation, and discloses a ceramic-lined polysulfone ultrafiltration membrane and a preparation method thereof.The preparation method comprises the following steps that S1, a membrane casting solution is prepared, specifically, polysulfone, a dipole solvent, PVP, CaSO4, ZnO, chalk and rosin are stirred at 60 DEG C till complete dissolution, standing and defoaming are conducted, and the transparent and viscous membrane casting solution is obtained; step S2, membrane scraping and forming: washing a ceramic substrate and a scraper cleanly, standing and drying, uniformly pouring the membrane casting liquid from one end of the ceramic substrate, and uniformly scraping the membrane casting liquid with the scraper to form a polysulfone initial membrane; and S3, solidification and shaping: putting the ceramic substrate covered with the polysulfone initial membrane into deionized water, and solidifying for 10-30 minutes to obtain the ceramic-lined polysulfone ultrafiltration membrane. The ceramic material is used for replacing polyester non-woven fabric to serve as an ultrafiltration membrane base material, meanwhile, the ceramic material is combined with the polysulfone material to form the composite ultrafiltration membrane, good chemical stability and mechanical strength are achieved, the service life can be effectively prolonged, and meanwhile high separation efficiency and anti-pollution performance are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane separation, and particularly to a ceramic-lined polysulfone ultrafiltration membrane and a preparation method thereof. Background Art

[0002] Ultrafiltration membrane technology is based on the sieving effect and the physical and chemical properties of the membrane surface. Under high-pressure driving, the solvent and low-molecular solutes in the solution can pass through the tiny pores on the membrane, while high-molecular solutes and larger molecules such as colloids are effectively intercepted, thereby achieving the separation and purification of substances. The ultrafiltration membrane surface has certain chemical properties and can selectively adsorb or repel certain specific substances, further enhancing its separation effect. The ultrafiltration membrane has high separation efficiency, can achieve precise separation of substances with different molecular sizes in the solution, is easy to operate, has low energy consumption, does not require the addition of chemical reagents, and avoids the risk of secondary pollution. It is widely used in the fields of food, pharmaceuticals, biology, chemical engineering, water treatment, and seawater desalination.

[0003] Currently, the main ultrafiltration membrane substrate is polyester non-woven fabric, which has the following defects:

[0004] 1. The membrane flux is limited, and the separation efficiency decreases significantly with the running time;

[0005] 2. Poor chemical stability, prone to hydrolysis or oxidative degradation in strong acid or strong base environments, and short service life;

[0006] 3. Insufficient mechanical strength, prone to membrane structure damage under long-term high-pressure operation;

[0007] 4. Prone to adsorb oily pollutants, requiring frequent chemical cleaning, increasing the operation and maintenance costs.

[0008] Polysulfone (PSF) materials are widely used as membrane materials due to their high glass transition temperature (195°C) and strong chemical corrosion resistance. However, the defects of traditional polyester non-woven fabric substrates limit the potential of polysulfone membranes.

[0009] Based on this, the present application provides a ceramic-lined polysulfone ultrafiltration membrane with high flux, good chemical stability, high mechanical strength, and strong anti-pollution performance and a preparation method thereof to solve the above problems. Summary of the Invention

[0010] The present invention aims to solve the technical problems existing in the prior art. To this end, the present invention provides a ceramic-lined polysulfone ultrafiltration membrane with high flux, good chemical stability, high mechanical strength, and strong anti-pollution performance and a preparation method thereof.

[0011] The technical solution adopted by the present invention to solve its technical problems is:

[0012] Provided is a preparation method of a ceramic-lined polysulfone ultrafiltration membrane, comprising the following steps:

[0013] Step S1, preparing a casting solution: Stir polysulfone, dipolar solvent, PVP, CaSO4, ZnO, chalk, and rosin at 60°C for 6 - 8 hours until completely dissolved, and then let it stand for degassing at 20 - 30°C for 15 - 20 hours to obtain a transparent and viscous casting solution.

[0014] Step S2, film scraping and forming: Rinse the ceramic substrate and the scraper with deionized water at room temperature and let them stand for drying. In an environment with a temperature of 20 - 25°C and a humidity of 50% - 75%, pour the casting solution uniformly from one end of the ceramic substrate, and scrape the casting solution evenly with a scraper with a thickness of 200μm to form an initial polysulfone film.

[0015] Step S3, coagulation and shaping: In an environment with a temperature of 20 - 25°C and a humidity of 50% - 75%, place the ceramic substrate covered with the initial polysulfone film into deionized water for coagulation for 10 - 30 min to obtain a ceramic - lined polysulfone ultrafiltration membrane with a thickness of 150 - 300μm.

[0016] In some alternative embodiments, in step S1, the dipolar solvent is any one of N - methyl - 2 - pyrrolidone, N,N - dimethylformamide, N,N - dimethylacetamide, and dimethyl sulfoxide.

[0017] In some alternative embodiments, in step S1, the casting solution is prepared according to the following mass parts:

[0018] 15 - 21 parts of polysulfone, 71 - 80 parts of dipolar solvent, 5 - 8 parts of PVP, 0.005 - 0.015 parts of CaSO4, 0.005 - 0.015 parts of ZnO, 0.005 - 0.010 parts of chalk, and 0.003 - 0.005 parts of rosin.

[0019] In some alternative embodiments, in step S2, the ceramic substrate is an α - alumina ceramic substrate with a thickness of 200μm - 300μm, a porosity of 60% - 80%, and its surface is treated by plasma activation.

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

[0021] The present invention uses a ceramic material to replace polyester non - woven fabric as the ultrafiltration membrane substrate, and at the same time combines with a polysulfone material to form a composite ultrafiltration membrane, which has good chemical stability and mechanical strength, can effectively improve the service life, and also has high separation efficiency and anti - pollution performance. Specific embodiments

[0022] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] Example 1

[0025] This embodiment provides a method for preparing a ceramic-lined polysulfone ultrafiltration membrane, including the following steps:

[0026] Step S1, preparing a casting solution: Stir 18 Kg of polysulfone (PSF), 78 Kg of N-methyl-2-pyrrolidone (NMP), 7 Kg of PVP, 15 g of CaSO4, 15 g of ZnO, 10 g of chalk, and 5 g of rosin at 60 °C for 6 hours until completely dissolved, and let it stand for defoaming at 20 - 30 °C for 16 hours to obtain a transparent and viscous casting solution;

[0027] Step S2, film scraping and forming: Rinse the ceramic substrate and the scraper with deionized water and let them stand for drying at room temperature. In an environment of 20 - 25 °C and 68% humidity, pour the casting solution evenly from one end of the ceramic substrate, and scrape the casting solution evenly with a scraper with a thickness of 200 μm to form an initial polysulfone membrane;

[0028] Step S3, coagulation and shaping: In an environment of 20 - 25 °C and 68% humidity, put the ceramic substrate covered with the initial polysulfone membrane into deionized water for coagulation for 15 min to obtain a ceramic-lined polysulfone ultrafiltration membrane with a thickness of 210 μm.

[0029] Test the ceramic-lined polysulfone ultrafiltration membrane prepared by the above preparation method. The test standard: "Ultrafiltration Membrane Test Method" GB / T 32360 - 2015.

[0030] Test results: Pure water permeability: 361 L / (m 2 ·h); BSA rejection rate: 91.3%.

[0031] Example 2

[0032] This embodiment provides a method for preparing a ceramic-lined polysulfone ultrafiltration membrane, including the following steps:

[0033] Step S1, preparing a casting solution: Stir 18 Kg of polysulfone (PSF), 78 Kg of N,N-dimethylformamide (DMF), 8 Kg of PVP, 15 g of CaSO4, 15 g of ZnO, 10 g of chalk, and 5 g of rosin at 60 °C for 6 hours until completely dissolved, and let it stand for defoaming at 20 - 30 °C for 16 hours to obtain a transparent and viscous casting solution;

[0034] Step S2, film scraping and forming: Rinse the ceramic substrate and the scraper with deionized water at room temperature, rinse them clean and leave them to stand for drying. In an environment of 20-25°C and 70% humidity, pour the casting solution uniformly from one end of the ceramic substrate, and use a scraper with a thickness of 200 μm to uniformly scrape the casting solution to form a polysulfone initial film;

[0035] Step S3, coagulation and shaping: In an environment of 20-25°C and 70% humidity, put the ceramic substrate covered with the polysulfone initial film into deionized water for coagulation for 15 minutes to obtain a ceramic-lined polysulfone ultrafiltration membrane with a thickness of 190 μm.

[0036] Test the ultrafiltration membrane of ceramic-lined polysulfone prepared by the above preparation method. The test standard: "Ultrafiltration Membrane Test Method" GB / T 32360-2015.

[0037] Test results: Pure water permeability: 375 L / (m 2 ·h); BSA rejection rate: 90.7%.

[0038] Example 3

[0039] This example provides a preparation method of an ultrafiltration membrane of ceramic-lined polysulfone, including the following steps:

[0040] Step S1, prepare the casting solution: Stir 18 Kg of polysulfone (PSF), 78 Kg of N,N-dimethylacetamide (DMAc), 8 Kg of PVP, 15 g of CaSO4, 15 g of ZnO, 10 g of chalk, and 5 g of rosin at 60°C for 6 hours until completely dissolved, and leave it to stand for defoaming at 20-30°C for 18 hours to obtain a transparent and viscous casting solution;

[0041] Step S2, film scraping and forming: Rinse the ceramic substrate and the scraper with deionized water at room temperature, rinse them clean and leave them to stand for drying. In an environment of 20-25°C and 55% humidity, pour the casting solution uniformly from one end of the ceramic substrate, and use a scraper with a thickness of 200 μm to uniformly scrape the casting solution to form a polysulfone initial film;

[0042] Step S3, coagulation and shaping: In an environment of 20-25°C and 55% humidity, put the ceramic substrate covered with the polysulfone initial film into deionized water for coagulation for 15 minutes to obtain a ceramic-lined polysulfone ultrafiltration membrane with a thickness of 190 μm.

[0043] Test the ultrafiltration membrane of ceramic-lined polysulfone prepared by the above preparation method. The test standard: "Ultrafiltration Membrane Test Method" GB / T 32360-2015.

[0044] Test results: Pure water permeability: 363 L / (m 2 ·h); BSA rejection rate: 91.9%.

[0045] Example 4

[0046] This example provides a method for preparing a ceramic-lined polysulfone ultrafiltration membrane, which includes the following steps:

[0047] Step S1, preparing the casting solution: Stir 18 Kg of polysulfone (PSF), 78 Kg of dimethyl sulfoxide (DMSO), 8 Kg of PVP, 15 g of CaSO4, 15 g of ZnO, 10 g of chalk, and 5 g of rosin at 60 °C for 6 hours until completely dissolved, and let it stand for defoaming at 20 - 30 °C for 16 hours to obtain a transparent and viscous casting solution;

[0048] Step S2, film scraping and forming: Rinse the ceramic substrate and the scraper with deionized water and let them stand for drying at room temperature. In an environment of 20 - 25 °C and 65% humidity, pour the casting solution evenly from one end of the ceramic substrate, and scrape the casting solution evenly with a scraper with a thickness of 200 μm to form a polysulfone initial film;

[0049] Step S3, coagulation and shaping: In an environment of 20 - 25 °C and 65% humidity, put the ceramic substrate covered with the polysulfone initial film into deionized water for coagulation for 15 min to obtain a ceramic-lined polysulfone ultrafiltration membrane with a thickness of 220 μm.

[0050] Test the ceramic-lined polysulfone ultrafiltration membrane prepared by the above preparation method. The test standard: "Ultrafiltration Membrane Test Method" GB / T 32360 - 2015.

[0051] Test results: Pure water permeability: 357 L / (m 2 ·h); BSA rejection rate: 92.1%.

[0052] Then, conduct the following tests on the ceramic-lined polysulfone ultrafiltration membrane in the above example:

[0053] Chemical stability test: Immerse it in 10% HCl or 10% NaOH for 30 days, and the membrane structure is intact without damage.

[0054] Thermal resistance test: Continuously operate at 150 °C for 1000 hours, and the flux decay rate < 5%.

[0055] The above are only the examples of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent structural or equivalent process transformations made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A method for preparing a ceramic-lined polysulfone ultrafiltration membrane, characterized in that: The following steps are involved: Step S1, preparing a casting solution: stirring polysulfone, a dipole solvent, PVP, CaSO4, ZnO, chalk, and rosin at 60° C. for 6 to 8 hours until they are completely dissolved, and standing and degassing at 20 to 30° C. for 15 to 20 hours to obtain a transparent and viscous casting solution; Step S2, film scraping: the ceramic substrate and the scraper are rinsed with deionized water at room temperature and left to dry, and the casting solution is evenly poured from one end of the ceramic substrate under a humidity environment of 20-25° C. and 50%-75%, and the casting solution is evenly scraped with a scraper with a thickness of 200 μm to form an initial polysulfone film; Step S3, coagulation and fixing: placing the ceramic substrate covered with the polysulfone initial membrane in deionized water for coagulation for 10 to 30 minutes at 20 to 25° C. and 50% to 75% humidity to obtain a ceramic-lined polysulfone ultrafiltration membrane with a thickness of 150 to 300 μm.

2. The preparation method according to claim 1, characterized in that: In the step S1, the dipolar solvent is any one of N-methyl-2-pyrrolidone, NN-dimethylformamide, NN-dimethylacetamide and dimethyl sulfoxide.

3. The preparation method according to claim 1, characterized in that: In step S1, the casting solution is prepared according to the following mass parts: 15-21 parts of polysulfone, 71-80 parts of dipolar solvent, 5-8 parts of PVP, 0.005-0.015 parts of CaSO4, 0.005-0.015 parts of ZnO, 0.005-0.010 parts of chalk, and 0.003-0.005 parts of rosin.

4. The preparation method according to claim 1, characterized in that: In the step S2, the ceramic substrate is an α-alumina ceramic substrate with a thickness of 200 μm to 300 μm and a porosity of 60% to 80%, and its surface is treated by plasma activation.

5. A ceramic lined polysulfone ultrafiltration membrane, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 4.