阅读说明：本技术 一种油水分离膜及其制备方法 (Oil-water separation membrane and preparation method thereof ) 是由 郭雅妮 郭晓航 李铭 于 2021-09-27 设计创作，主要内容包括：本发明公开了一种油水分离膜及其制备方法,属于油水分离膜技术领域。该油水分离膜的制备方法,包括以下步骤：S1、将二氧化硅分散于水中并搅拌,之后加入聚乙烯吡咯烷酮和过硫酸钾继续搅拌,之后超声得到第一混合物；S2、将所述第一混合物与聚乙烯醇水溶液混合得到第二混合物,将所述第二混合物在50-60℃下搅拌；S3、将步骤S2处理后的第二混合物浸涂于载体上,将浸涂后的载体置于交联剂蒸汽中处理得到所述油水分离膜。本发明还包括上述制备方法制得的油水分离膜。该油水分离膜具有较好的稳定性,在不同的盐溶液和pH条件下都具有优异的超疏油性能。(The invention discloses an oil-water separation membrane and a preparation method thereof, and belongs to the technical field of oil-water separation membranes. The preparation method of the oil-water separation membrane comprises the following steps: s1, dispersing silicon dioxide in water and stirring, adding polyvinylpyrrolidone and potassium persulfate to continue stirring, and then carrying out ultrasonic treatment to obtain a first mixture; s2, mixing the first mixture with a polyvinyl alcohol aqueous solution to obtain a second mixture, and stirring the second mixture at 50-60 ℃; s3, dip-coating the second mixture processed in the step S2 on a carrier, and placing the dip-coated carrier in cross-linking agent steam for processing to obtain the oil-water separation membrane. The invention also discloses the oil-water separation membrane prepared by the preparation method. The oil-water separation membrane has good stability and excellent super-oleophobic performance under different salt solutions and pH conditions.)

1. The preparation method of the oil-water separation membrane is characterized by comprising the following steps:

s1, dispersing silicon dioxide in water and stirring, adding polyvinylpyrrolidone and potassium persulfate to continue stirring, and then carrying out ultrasonic treatment to obtain a first mixture;

s2, mixing the first mixture with a polyvinyl alcohol aqueous solution to obtain a second mixture, and stirring the second mixture at 50-60 ℃;

s3, dip-coating the second mixture processed in the step S2 on a carrier, and placing the dip-coated carrier in cross-linking agent steam for processing to obtain the oil-water separation membrane.

2. The method for producing an oil-water separation membrane according to claim 1, wherein in step S1, the material ratio of the silica to the water is (0.1 to 0.9) g:10 mL.

3. The method for producing an oil-water separation membrane according to claim 1, wherein in step S1, the mass ratio of the silica to the polyvinylpyrrolidone to the potassium persulfate is (0.1-0.9): (0-1).

4. The method for producing an oil-water separation membrane according to claim 1, wherein the time for the ultrasonic treatment in step S1 is 10 to 20 minutes.

5. The method for producing an oil-water separation membrane according to claim 1, wherein in step S2, the polyvinyl alcohol aqueous solution has a mass concentration of 8% to 10%; the mass ratio of the polyvinyl alcohol in the polyvinyl alcohol aqueous solution to the silicon dioxide is 1 (0.1-0.9).

6. The method for producing an oil-water separation membrane according to claim 1, wherein in step S3, the crosslinking agent is glutaraldehyde.

7. The method for producing an oil-water separation membrane according to claim 1, further comprising, before step S2, preparing an aqueous polyvinyl alcohol solution: mixing polyvinyl alcohol with water, and stirring at 80-90 deg.C.

8. The method for producing an oil-water separation membrane according to claim 1, wherein in step S2, the second mixture is stirred at 50 to 60 ℃ for 2 to 3 hours.

9. The method for producing an oil-water separation membrane according to claim 1, wherein in step S1, the silica is dispersed in water and stirred for 20 to 30 minutes, and then the polyvinylpyrrolidone and the potassium persulfate are added and stirring is continued for 20 to 30 minutes.

10. An oil-water separation membrane produced by the production method according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of oil-water separation membranes, in particular to an oil-water separation membrane and a preparation method thereof.

Background

The traditional oil-water separation methods mainly comprise two methods, namely a physical method and a chemical method: substances used in a physical method comprise activated carbon, organic clay, zeolite and the like, and the substances can absorb water while absorbing oil, so that the separation process is complicated and the efficiency is low; the chemical methods comprise oxidation, electrochemical process, photocatalytic treatment, ozone treatment, demulsification and other methods, toxic compounds are used in the separation process, the cost is increased, and secondary pollution is generated. In the last decades, the application of membrane separation technology has become an important oil-water separation technology, and its advantages are that it can work without adding other chemicals, has lower energy requirement, simple process and easy operation, but may require organic solvent to cause pollution in the preparation process.

Among a plurality of hydrophilic polymers, polyvinyl alcohol has wide sources, cheap raw materials and simple synthesis, so the polyvinyl alcohol has great application prospect in the field of oil-water separation. The polyvinyl alcohol is prepared by vinyl acetate through alcoholysis reaction and polymerization, and is a white, powdery, safe and nontoxic water-soluble high-molecular polymer. The polyvinyl alcohol has good film forming property. However, when a single polymer membrane is used as a separation material, the stability is poor, and the problem that the single polymer membrane cannot resist acid, alkali or salt exists.

Disclosure of Invention

The invention aims to overcome the technical defects, provides an oil-water separation membrane and a preparation method thereof, and solves the technical problem that the oil-water separation membrane in the prior art cannot resist acid, alkali or salt.

In order to achieve the technical purpose, the technical scheme of the invention provides a preparation method of an oil-water separation membrane, which comprises the following steps:

s1, dispersing silicon dioxide in water and stirring, adding polyvinylpyrrolidone and potassium persulfate to continue stirring, and then carrying out ultrasonic treatment to obtain a first mixture;

s2, mixing the first mixture with a polyvinyl alcohol aqueous solution to obtain a second mixture, and stirring the second mixture at 50-60 ℃;

s3, dip-coating the second mixture processed in the step S2 on a carrier, and placing the dip-coated carrier in cross-linking agent steam for processing to obtain the oil-water separation membrane.

Further, in step S1, the material ratio of the silica to the water is (0.1 to 0.9) g:10 mL.

Further, in step S1, the mass ratio of the silica, the polyvinylpyrrolidone and the potassium persulfate is (0.1-0.9): (0-1).

Further, in step S1, the time of the ultrasonic treatment is 10 to 20 minutes.

Further, in step S2, the mass concentration of the polyvinyl alcohol aqueous solution is 8% to 10%; the mass ratio of the polyvinyl alcohol in the polyvinyl alcohol aqueous solution to the silicon dioxide is 1 (0.1-0.9).

Further, in step S3, the cross-linking agent is glutaraldehyde.

Further, before step S2, preparing an aqueous solution of polyvinyl alcohol: mixing polyvinyl alcohol with water, and stirring at 80-90 deg.C.

Further, in step S2, the second mixture is stirred at 50-60 ℃ for 2-3 h.

Further, in step S1, the silica is dispersed in water and stirred for 20 to 30 minutes, after which the polyvinylpyrrolidone and the potassium persulfate are added and stirring is continued for 20 to 30 minutes.

In addition, the invention also provides an oil-water separation membrane prepared by the preparation method.

Compared with the prior art, the invention has the beneficial effects that: according to the invention, polyvinyl alcohol, polyvinylpyrrolidone and silicon dioxide are combined under the stirring and ultrasonic effects to prepare the oil-water separation membrane with good underwater oleophobic property, and the polyvinyl alcohol and polyvinylpyrrolidone form a cross-linked network under the action of cross-linking agent steam, so that the stability of the oil-water separation membrane is improved, and the oil-water separation membrane has excellent super oleophobic properties under different salt solutions and pH conditions.

Drawings

FIG. 1 is a graph showing the results of the underwater oil contact angles of the oil-water separation membranes obtained in examples 1 to 5 of the present invention and comparative example 1.

FIG. 2 is a graph showing the results of the underwater oil contact angles of the oil-water separation membrane prepared in example 1 of the present invention in different salt solutions.

FIG. 3 is a graph showing the results of the underwater oil contact angles of the oil-water separation membrane prepared in example 1 of the present invention in solutions under different pH conditions.

Detailed Description

The specific embodiment provides a preparation method of an oil-water separation membrane, which comprises the following steps:

s1, dispersing silicon dioxide in water, stirring for 20-30 minutes, adding polyvinylpyrrolidone and potassium persulfate, continuing stirring for 20-30 minutes, and performing ultrasonic treatment for 10-20 minutes to obtain a first mixture; mixing polyvinyl alcohol with water, and stirring at 80-90 deg.C for 5-6h to obtain polyvinyl alcohol water solution; the material ratio of the silicon dioxide to the water is (0.1-0.9) g:10 mL; the mass ratio of the silicon dioxide, the polyvinylpyrrolidone and the potassium persulfate is (0.1-0.9): (0-1): 0-1); the molecular weight of the polyvinylpyrrolidone is about 4 to 5 ten thousand; the mass concentration of the polyvinyl alcohol aqueous solution is 8-10%; the mass ratio of the polyvinyl alcohol in the polyvinyl alcohol aqueous solution to the silicon dioxide is 1 (0.1-0.9); the polyvinyl alcohol has a molecular weight of about 8 ten thousand;

s2, mixing the first mixture with a polyvinyl alcohol aqueous solution to obtain a second mixture, and stirring the second mixture at 50-60 ℃ for 2-3 h;

s3, dip-coating the second mixture processed in the step S2 on a carrier, and placing the dip-coated carrier in glutaraldehyde steam as a cross-linking agent for processing to obtain the oil-water separation membrane; the carrier is a 200-mesh steel wire mesh.

The specific embodiment also provides an oil-water separation membrane prepared by the preparation method.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and 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.

Example 1

The embodiment provides an oil-water separation membrane, which is prepared by the following steps:

s1, dispersing 0.1g of silicon dioxide in 10ml of deionized water, magnetically stirring for 20 minutes at normal temperature, adding 0.2g of polyvinylpyrrolidone and 0.2g of potassium persulfate, continuously magnetically stirring for 20 minutes at normal temperature, and then carrying out ultrasonic vibration treatment for 10 minutes to obtain a first mixture; mixing 5g of polyvinyl alcohol with 50ml of water, and magnetically stirring for 5 hours at 90 ℃ to obtain a polyvinyl alcohol aqueous solution; polyvinylpyrrolidone has a molecular weight of about 4 ten thousand; the polyvinyl alcohol has a molecular weight of about 8 ten thousand;

s2, mixing the first mixture with 10mL of polyvinyl alcohol aqueous solution, magnetically stirring for 1h to obtain a second mixture, and stirring the second mixture for 2h at 60 ℃ in a water bath;

s3, dip-coating the second mixture processed in the step S2 on a 200-mesh steel wire mesh, and placing the dip-coated steel wire mesh in glutaraldehyde steam as a cross-linking agent for processing for 24 hours to obtain the oil-water separation membrane.

The underwater methylene dichloride contact angle of the oil-water separation membrane prepared in the embodiment is 150.53 degrees.

Example 2

The embodiment provides an oil-water separation membrane, which is prepared by the following steps:

s1, dispersing 0.3g of silicon dioxide in 10ml of deionized water, magnetically stirring at normal temperature for 30 minutes, adding 0.4g of polyvinylpyrrolidone and 0.4g of potassium persulfate, continuously magnetically stirring at normal temperature for 20 minutes, and then carrying out ultrasonic oscillation treatment for 15 minutes to obtain a first mixture; mixing 5g of polyvinyl alcohol with 50ml of water, and magnetically stirring for 6 hours at 80 ℃ to obtain a polyvinyl alcohol aqueous solution; polyvinylpyrrolidone has a molecular weight of about 4 ten thousand; the polyvinyl alcohol has a molecular weight of about 8 ten thousand;

s2, mixing the first mixture with 10mL of polyvinyl alcohol aqueous solution, magnetically stirring for 1h to obtain a second mixture, and stirring the second mixture for 3h at 50 ℃ in a water bath;

s3, dip-coating the second mixture processed in the step S2 on a 200-mesh steel wire mesh, and placing the dip-coated steel wire mesh in glutaraldehyde steam as a cross-linking agent for processing for 24 hours to obtain the oil-water separation membrane.

The underwater dichloromethane contact angle of the oil-water separation membrane prepared in the embodiment is 151.3 degrees.

Example 3

The embodiment provides an oil-water separation membrane, which is prepared by the following steps:

s1, dispersing 0.5g of silicon dioxide in 10ml of deionized water, magnetically stirring at normal temperature for 20 minutes, adding 0.6g of polyvinylpyrrolidone and 0.6g of potassium persulfate, continuously magnetically stirring at normal temperature for 20 minutes, and then carrying out ultrasonic vibration treatment for 20 minutes to obtain a first mixture; mixing 4g of polyvinyl alcohol with 50ml of water, and magnetically stirring for 5 hours at 90 ℃ to obtain a polyvinyl alcohol aqueous solution; polyvinylpyrrolidone has a molecular weight of about 5 ten thousand; the polyvinyl alcohol has a molecular weight of about 8 ten thousand;

s2, mixing the first mixture with 10mL of polyvinyl alcohol aqueous solution, magnetically stirring for 1h to obtain a second mixture, and stirring the second mixture for 2h at 60 ℃ in a water bath;

s3, dip-coating the second mixture processed in the step S2 on a 200-mesh steel wire mesh, and placing the dip-coated steel wire mesh in glutaraldehyde steam as a cross-linking agent for processing for 24 hours to obtain the oil-water separation membrane.

The underwater dichloromethane contact angle of the oil-water separation membrane prepared in the embodiment is 151.3 degrees.

Example 4

The embodiment provides an oil-water separation membrane, which is prepared by the following steps:

s1, dispersing 0.7g of silicon dioxide in 10ml of deionized water, magnetically stirring for 20 minutes at normal temperature, adding 0.8g of polyvinylpyrrolidone and 0.8g of potassium persulfate, continuously magnetically stirring for 20 minutes at normal temperature, and then carrying out ultrasonic vibration treatment for 10 minutes to obtain a first mixture; mixing 5g of polyvinyl alcohol with 50ml of water, and magnetically stirring for 5 hours at 90 ℃ to obtain a polyvinyl alcohol aqueous solution; polyvinylpyrrolidone has a molecular weight of about 5 ten thousand; the polyvinyl alcohol has a molecular weight of about 8 ten thousand;

s2, mixing the first mixture with 10mL of polyvinyl alcohol aqueous solution, magnetically stirring for 1h to obtain a second mixture, and stirring the second mixture for 2h at 60 ℃ in a water bath;

s3, dip-coating the second mixture processed in the step S2 on a 200-mesh steel wire mesh, and placing the dip-coated steel wire mesh in glutaraldehyde steam as a cross-linking agent for processing for 24 hours to obtain the oil-water separation membrane.

The underwater dichloromethane contact angle of the oil-water separation membrane prepared in the embodiment is 150.4 degrees.

Example 5

The embodiment provides an oil-water separation membrane, which is prepared by the following steps:

s1, dispersing 0.9g of silicon dioxide in 10ml of deionized water, magnetically stirring for 25 minutes at normal temperature, adding 1g of polyvinylpyrrolidone and 1g of potassium persulfate, continuously magnetically stirring for 25 minutes at normal temperature, and then carrying out ultrasonic vibration treatment for 15 minutes to obtain a first mixture; mixing 5g of polyvinyl alcohol with 50ml of water, and magnetically stirring for 6 hours at 85 ℃ to obtain a polyvinyl alcohol aqueous solution; polyvinylpyrrolidone has a molecular weight of about 5 ten thousand; the polyvinyl alcohol has a molecular weight of about 8 ten thousand;

s2, mixing the first mixture with 10mL of polyvinyl alcohol aqueous solution, magnetically stirring for 1h to obtain a second mixture, and stirring the second mixture for 2h at 60 ℃ in a water bath;

s3, dip-coating the second mixture processed in the step S2 on a 200-mesh steel wire mesh, and placing the dip-coated steel wire mesh in glutaraldehyde steam as a cross-linking agent for processing for 24 hours to obtain the oil-water separation membrane.

The underwater dichloromethane contact angle of the oil-water separation membrane prepared in the embodiment is 150.3 degrees.

Comparative example 1

This comparative example differs from example 1 in that no silica is added and the other steps and process conditions are the same.

The oil-water separation membranes prepared in examples 1 to 5 were subjected to performance tests:

1. contact Angle measurement

The contact angles of the underwater oils on the surfaces of the various oil-water separation membranes were measured respectively using a contact angle tester (DSA-100, KRUSS, Germany) to investigate the wettability thereof, and the results are shown in FIGS. 1 to 3.

As can be seen from FIG. 1, the underwater dichloromethane contact angles of the oil-water separation membranes prepared in examples 1 to 5 are all above 150 degrees, and the oil-water separation membranes prepared in comparative example 1 have a super-oleophobic property, and the underwater dichloromethane contact angle of the oil-water separation membranes prepared in comparative example 1 is 148.8 degrees.

The oil-water separation membrane prepared in example 1 was charged with NaCl, KCl, and Mg (NO) at a concentration of 1mol/L, respectively₃)₂、CaCl₂、Al(NO₃)₃In the salt solution and the aqueous solution, the contact angle of the oil-water separation membrane with the underwater dichloromethane in different salt solutions is detected, and the result is shown in fig. 2, and it can be seen from fig. 2 that the oil-water separation membrane shows superoleophobic property in different salt solutions.

As shown in fig. 3, it can be seen from fig. 3 that the oil-water separation membrane exhibits superoleophobic properties under the condition of pH 1 to 11 and exhibits oleophobic properties in the solution of pH 12.

2. Testing of oil-water separation efficiency

50mL of water (blue-dyed with methylene blue) and 50mL of oil (red-dyed with oil Red O) were taken, and the mixture was poured into an oil-water separator with stirring. Since the oil-water separation membrane filter has an oil-separating effect, the volume of water after separation was recorded, and the results are shown in table 1.

Calculating the oil-water separation efficiency eta according to a formula:

in the formula: v represents the volume of water after separation, V₀Representing the volume in the initial oil water mixture.

TABLE 1 flux and efficiency of oil-water separation membranes of examples 1-5 and comparative example 1

	flux/(L/hm)2)	Separation efficiency (%)
			Example 1	7153.5	98.5
Example 2	7178.46	98.2
			Example 3	7153.5	98.5
Example 4	6457.39	98.0
			Example 5	6946.35	98.5
Comparative example 1	6031.27	87.3

As can be seen from Table 1, the membranes for oil-water separation obtained in examples 1 to 5 had high flux, which was 7178.46L/hm²The separation efficiency is as high as 98.5%, and the oil-water separation effect of the comparative example 1 is poor.

Other advantageous effects

1) In the reaction process of the preparation method provided by the invention, the polyvinyl alcohol and the polyvinylpyrrolidone form a cross-linked network, so that the stability of the oil-water separation membrane is improved. The oil-water separation membrane with good underwater oleophobic property is prepared by combining polyvinyl alcohol, polyvinylpyrrolidone and silicon dioxide.

2) The polyvinyl alcohol and the polyvinylpyrrolidone adopted by the oil-water separation membrane are both easily soluble in water, and no organic solvent is needed in the whole preparation process, so that no pollution is caused; the addition of the inorganic particle silicon dioxide increases the roughness of the surface of the composite membrane, so that the underwater oleophobic property of the membrane is improved; the addition of the polyvinylpyrrolidone increases the hydrophilicity of the separation membrane, so that the oil-water separation is more efficient, a cross-linked network can be formed with the polyvinyl alcohol to improve the stability of the separation membrane, and the polyvinylpyrrolidone can be used as a dispersing agent to reduce the agglomeration of silicon dioxide.

3) Compared with other methods, the preparation method has the advantages of no environmental pollution problem, environmental friendliness and excellent product comprehensive performance, so the preparation method has potential application prospects in the field of oil-water separation.

The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.