阅读说明：本技术 有机蒙脱土/二氧化钛复合颗粒聚偏氟乙烯膜的制备方法 (Preparation method of organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane ) 是由 李三喜 蒋大富 欧阳园园 于 2021-09-18 设计创作，主要内容包括：本发明涉及一种聚偏氟乙烯膜的方法,尤其涉及一种有机蒙脱土/二氧化钛复合颗粒聚偏氟乙烯膜的制备方法,属于光催化技术领域,能够降解常见的水体有机污染物。有机蒙脱土/二氧化钛复合颗粒聚偏氟乙烯膜的制备方法,步骤为：1)有机蒙脱土混合液的配备；2)钛源混合液的配备；3)复合颗粒前驱体制备；4)复合颗粒制备；5)铸膜液的配备；6)有机蒙脱土/二氧化钛聚偏氟乙烯膜的制备：将铸膜液浇铸在光滑的玻璃板上,使用平板铸膜机铸膜,铸膜结束时将玻璃板连同推好的膜溶液放置水中浸泡20-24h,在此过程中每隔6-8h换水去除残留溶剂,得到有机蒙脱土/二氧化钛聚偏氟乙烯膜。本发明的优点效果：本发明产品原料易得,制备方法简便,膜产品可大批量生产且不会对环境造成危害,且对水体中有机污染物有显著降解效果,降解有机污染物能耗低,时间短。本发明光催化效率良好。(The invention relates to a method for preparing a polyvinylidene fluoride membrane, in particular to a method for preparing an organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane, which belongs to the technical field of photocatalysis and can degrade common water organic pollutants. The preparation method of the organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane comprises the following steps: 1) preparing organic montmorillonite mixed liquor; 2) preparing a titanium source mixed solution; 3) preparing a composite particle precursor; 4) preparing composite particles; 5) preparing a casting solution; 6) preparing an organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane: and casting the membrane casting solution on a smooth glass plate, using a flat membrane casting machine to cast a membrane, placing the glass plate and the pushed membrane solution into water to soak for 20-24h when the membrane casting is finished, and changing water every 6-8h in the process to remove residual solvent to obtain the organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane. The invention has the advantages and effects that: the raw materials of the product are easy to obtain, the preparation method is simple and convenient, the film product can be produced in large scale and does not cause harm to the environment, and the film product has obvious degradation effect on organic pollutants in water, has low energy consumption for degrading the organic pollutants and short time. The invention has good photocatalysis efficiency.)

1. The preparation method of the organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane is characterized by comprising the following steps:

1) preparing organic montmorillonite mixed liquor: putting organic montmorillonite and a metal ion chelating agent into a container, sequentially adding deionized water and absolute ethyl alcohol for ultrasonic dispersion, adding hydrochloric acid into the solution after the ultrasonic dispersion is finished, and adjusting the pH value to ensure that the pH value is =1-4 to form a uniform organic montmorillonite mixed solution;

2) preparing a titanium source mixed solution: adding a titanium source into a container filled with absolute ethyl alcohol, and stirring by a magnetic stirrer to form a titanium source mixed solution;

3) preparing a composite particle precursor: rapidly stirring the titanium source mixed solution in a room-temperature water bath, gradually adding the titanium source mixed solution into the organic montmorillonite mixed solution at a constant speed, and stirring and heating in a water bath at 40-60 ℃ after the titanium source mixed solution is added to obtain milky gel;

4) preparing composite particles: drying the milky white gel at 80-100 ℃ for 15-20h to obtain yellow crystals, grinding the crystals to obtain light yellow powder, carrying out heat treatment at 400-600 ℃ for 2-6h, and fully grinding the heat-treated crystals to prepare the composite particles of titanium dioxide and organic montmorillonite;

5) preparing a casting solution: adding the composite particles, the organic solvent and the polyvinylidene fluoride into a container according to a certain proportion for dissolving and ultrasonically dispersing, mechanically stirring the solution for 12 hours at 40-60 ℃ after the ultrasonic treatment is finished, and standing and degassing for 3-5 hours to obtain a membrane casting solution;

6) preparing an organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane: and casting the membrane casting solution on a smooth glass plate, using a flat membrane casting machine to cast a membrane, placing the glass plate and the pushed membrane solution into water to soak for 20-24h when the membrane casting is finished, and changing water every 6-8h in the process to remove residual solvent to obtain the organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane.

2. The method of claim 1, wherein the organic montmorillonite is cetyltrimethylammonium bromide or octadecyltrimethylammonium bromide.

3. The method for preparing an organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane according to claim 1, wherein the metal ion chelating agent is sodium potassium tartrate or glacial acetic acid.

4. The method for preparing the organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane according to claim 1, characterized in that the ultrasonic dispersion in the step 1) is carried out for 20-30 minutes.

5. The method of claim 1, wherein the titanium source is tetrabutyl titanate.

6. The method for preparing the organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane of claim 1, wherein the time of the strong stirring of the magnetic stirrer in the step 2) is 20-40 minutes.

7. The method for preparing polyvinylidene fluoride membrane of organic montmorillonite/titanium dioxide composite particles as claimed in claim 1, wherein said step 5) composite particles: organic solvent: polyvinylidene fluoride = 0.1-1%: 80% -89.9%: 10% -19%, and ultrasonically dispersing the composite particles, the organic solvent and the polyvinylidene fluoride in a container for 20-30 minutes.

8. The method for preparing the polyvinylidene fluoride membrane of the organic montmorillonite/titanium dioxide composite particles as claimed in claim 1, wherein the polyvinylidene fluoride has a model number of 6010 or kf 850.

9. The method for preparing the organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane according to claim 1, characterized in that the organic solvent is one or a mixture of N, N-dimethylformamide and N, N-dimethylacetamide.

10. The method for preparing an organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane according to claim 1, wherein the step 6) is to cast the membrane by using a flat membrane casting machine at a push speed of 20-25 mm/S.

Technical Field

The invention relates to a method for preparing a polyvinylidene fluoride membrane, in particular to a method for preparing an organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane, which belongs to the technical field of photocatalysis and can degrade common water organic pollutants.

Background

Industrial development is accompanied by a large number of toxic pollutants which are harmful to the environment, to human health and difficult to degrade by natural means. Under the action of light, the photocatalyst can generate a strong catalytic degradation function so as to degrade organic pollutants in the water body. Titanium dioxide is a photocatalyst widely used for photodegradation of organic pollutants, and cannot effectively utilize sunlight because the band gap width of the titanium dioxide is 3.0-3.2 eV. It is therefore necessary to modify it. The composite semiconductor modification method is simple to operate and remarkable in effect, and is considered as a promising modification method. The modified composite photocatalyst particles are beneficial to the transfer of photo-generated electrons and holes, and the service life of the photo-generated holes is prolonged so as to improve the photocatalytic activity of the photo-generated electrons and the photo-generated holes.

The organic montmorillonite is naturally stored and is rich and cheap, and the self component comprises Al₂O₃，MgO，SiO₂And the organic montmorillonite and the titanium dioxide are combined in a composite semiconductor mode to degrade organic pollutants, so that the method has great potential for treating the organic sewage. In addition, the traditional photocatalyst has the defects of difficult recovery, small contact area with water and the like.

Disclosure of Invention

The invention provides a preparation method of an organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane with a photocatalytic effect, which aims to solve the technical problem that the traditional treatment mode is not complete in degrading organic pollutants in water.

To achieve the above object, the preparation method of the organic montmorillonite/titanium dioxide composite particle polyvinylidene fluoride membrane of the invention comprises the following steps:

1) preparing organic montmorillonite mixed liquor: putting organic montmorillonite and a metal ion chelating agent into a container, sequentially adding deionized water and absolute ethyl alcohol for ultrasonic dispersion, adding hydrochloric acid into the solution after the ultrasonic dispersion is finished, and adjusting the pH value to ensure that the pH value is =1-4 to form a uniform organic montmorillonite mixed solution;

2) preparing a titanium source mixed solution: adding a titanium source into a container filled with absolute ethyl alcohol, and stirring by a magnetic stirrer to form a titanium source mixed solution;

3) preparing a composite particle precursor: rapidly stirring the titanium source mixed solution in a room-temperature water bath, gradually adding the titanium source mixed solution into the organic montmorillonite mixed solution at a constant speed, and stirring and heating in a water bath at 40-60 ℃ after the titanium source mixed solution is added to obtain milky gel;

4) preparing composite particles: drying the milky white gel at 80-100 ℃ for 15-20h to obtain yellow crystals, grinding the crystals to obtain light yellow powder, carrying out heat treatment at 400-600 ℃ for 2-6h, and fully grinding the heat-treated crystals to prepare the composite particles of titanium dioxide and organic montmorillonite;

5) preparing a casting solution: adding the composite particles, the organic solvent and the polyvinylidene fluoride into a container according to a certain proportion for dissolving and ultrasonically dispersing, mechanically stirring the solution for 12 hours at 40-60 ℃ after the ultrasonic treatment is finished, and standing and degassing for 3-5 hours to obtain a membrane casting solution;

6) preparing an organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane: and casting the membrane casting solution on a smooth glass plate, using a flat membrane casting machine to cast a membrane, placing the glass plate and the pushed membrane solution into water to soak for 20-24h when the membrane casting is finished, and changing water every 6-8h in the process to remove residual solvent to obtain the organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane.

The organic montmorillonite is cetyl trimethyl ammonium bromide or octadecyl trimethyl ammonium bromide.

The metal ion chelating agent is sodium potassium tartrate or glacial acetic acid.

The ultrasonic dispersion in the step 1) is carried out for 20-30 minutes.

The titanium source is tetrabutyl titanate.

The time for the magnetic stirrer in the step 2) to stir strongly is 20-40 minutes.

The step 5) composite particles: organic solvent: polyvinylidene fluoride = 0.1-0.5%: 83.5% -83.9%: 16 percent of composite particles, organic solvent and polyvinylidene fluoride are dispersed in a container for 20 to 30 minutes by ultrasound.

The polyvinylidene fluoride is 6010 or kf 850.

The organic solvent is one or a mixture of N, N-dimethylformamide and N, N-dimethylacetamide.

And 6) casting the film by using a flat film casting machine at the advancing speed of 20-25 mm/S.

The invention has the advantages and effects that: the raw materials of the product are easy to obtain, the preparation method is simple and convenient, the film product can be produced in large scale and does not cause harm to the environment, and the film product has obvious degradation effect on organic pollutants in water, has low energy consumption for degrading the organic pollutants and short time. The invention has good photocatalysis efficiency. The invention effectively avoids the problem that the photocatalyst can not be recycled by combining the photocatalyst with the polymer film substrate. Meanwhile, the high specific surface area of the membrane enlarges the contact of the photocatalyst and the water body, and improves the utilization rate of the photocatalyst.

Detailed Description

The present invention will be described in detail below.

Example 1

Weighing 11.732g of hexadecyl trimethyl ammonium bromide and 15mL of glacial acetic acid in a beaker, sequentially adding 50mL of deionized water and 200mL of absolute ethyl alcohol, ultrasonically dispersing for 20min, dripping hydrochloric acid into the solution after the ultrasonic treatment is finished, and adjusting the pH value to ensure that the pH value is =1 to form a uniform organic montmorillonite mixed solution;

dripping 50ml of tetrabutyl titanate into a beaker filled with 180ml of absolute ethyl alcohol, and stirring for 25min by a magnetic stirrer to form a titanium source mixed solution;

rapidly stirring the titanium source mixed solution in a room-temperature water bath, dropwise adding the titanium source mixed solution into the organic montmorillonite mixed solution, and stirring and heating the titanium source mixed solution in a water bath at 40 ℃ for about 1 hour after the titanium source mixed solution is added, thus obtaining milky gel;

drying the milky white gel at 80 ℃ for 20h to obtain yellow crystals, grinding to obtain light yellow powder, performing heat treatment at 600 ℃ for 2h, uniformly grinding the heat-treated crystals, and preparing titanium dioxide and organic montmorillonite in a ratio of 1: 1 proportion of composite photocatalyst nano particles;

adding 0.05g of composite particles, 8.5g of 6010 polyvinylidene fluoride and 41.45g of N, N-dimethylformamide into a container, dissolving and ultrasonically dispersing for 20min, mechanically stirring for 12h at 60 ℃ after ultrasonic treatment, and standing and degassing for 5h to obtain a casting solution;

the casting solution was cast on a smooth glass plate, cast using a flat plate casting machine, and cast at a rate of 25 mm/S. And (3) placing the obtained membrane in water, changing the water once every 6 hours, and changing for 4 times to obtain the organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane.

The film was cut into 0.00070147m in area²The round is used for the experiment of degrading organic pollutants. The membrane was adsorbed in 20ml/g rhodamine, methyl blue for 30min, and a sample was taken for the original solution to test spectrophotometry. And (3) irradiating the adsorption-balanced membrane for 20min by using an ultraviolet lamp, taking part of the solution after the irradiation for testing the spectrophotometric value of the solution after photocatalysis, and calculating to obtain the three degradation efficiencies of the prepared 0.1wt% polymer membrane to 20ml/g methyl blue and rhodamine in 20min respectively as shown in table 1.

The degradation rate was calculated as follows:

（1-A₁/A₀）×100%

wherein A is₀、A₁The absorbances of methyl blue and rhodamine before and after degradation respectively

Example 2

11.732g of octadecyl trimethyl ammonium bromide and 15mL of potassium sodium tartrate are weighed in a beaker, 50mL of deionized water and 200mL of absolute ethyl alcohol are sequentially added for ultrasonic dispersion for 30min, hydrochloric acid is dropped into the solution after the ultrasonic dispersion is finished, and the pH value is adjusted to ensure that the pH value is =3 to form uniform organic montmorillonite mixed solution;

dripping 50ml of tetrabutyl titanate into a beaker filled with 180ml of absolute ethyl alcohol, and stirring for 40min by a magnetic stirrer to form a titanium source mixed solution;

rapidly stirring the titanium source mixed solution in a room-temperature water bath, dropwise adding the titanium source mixed solution into the organic montmorillonite mixed solution at the speed of 2 drops per second, stirring and heating the titanium source mixed solution in a 60 ℃ water bath for about 1 hour after the addition is finished to obtain a milky colloid, drying the milky colloid at the temperature of 100 ℃ for about 15 hours to obtain yellow crystals, grinding the yellow crystals to obtain light yellow powder, performing heat treatment at the temperature of 400 ℃ for 6 hours, uniformly grinding the heat-treated crystals, and preparing titanium dioxide and organic montmorillonite in a ratio of 1: 1 proportion of composite photocatalyst nano particles;

mixing 0.15g of composite particles, 8.5g of kf850 polyvinylidene fluoride and 41.35g of N, N-dimethylformamide, mechanically stirring for 12h at 40 ℃, standing and degassing for 3h to obtain a casting solution;

the casting solution was cast on a smooth glass plate, cast using a flat plate casting machine, and cast at a rate of 20 mm/S. And (3) placing the obtained membrane in water, changing the water once every 5 hours, and changing for 4 times to obtain the organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane.

The film was cut into 0.00070147m in area²The round is used for the experiment of degrading organic pollutants. The membrane was adsorbed in 20ml/g rhodamine, methyl blue for 30min, and a sample was taken for the original solution to test spectrophotometry. And (3) irradiating the adsorption-balanced membrane for 20min by using an ultraviolet lamp, taking part of the solution after the irradiation for testing the spectrophotometric value of the solution after photocatalysis, and calculating to obtain the three degradation efficiencies of the prepared 0.3wt% polymer membrane to 20ml/g methyl blue and rhodamine in 20min respectively as shown in table 1.

Example 3

Weighing 11.732g of hexadecyl trimethyl ammonium bromide and 15mL of glacial acetic acid in a beaker, sequentially adding 50mL of deionized water and 200mL of absolute ethyl alcohol, ultrasonically dispersing for 25min, dripping hydrochloric acid into the solution after the ultrasonic treatment is finished, and adjusting the pH value to enable the pH value to be =4 to form a uniform organic montmorillonite mixed solution;

dripping 50ml of tetrabutyl titanate into a beaker filled with 180ml of absolute ethyl alcohol, and stirring for 25min by a magnetic stirrer to form a titanium source mixed solution;

rapidly stirring the titanium source mixed solution in a room-temperature water bath, dropwise adding the titanium source mixed solution into the organic montmorillonite mixed solution, and stirring and heating the titanium source mixed solution in a water bath at 50 ℃ for about 1 hour after the titanium source mixed solution is added, thus obtaining milky gel;

drying the milky white gel at 90 ℃ for 18h to obtain yellow crystals, grinding to obtain light yellow powder, performing heat treatment at 500 ℃ for 4h, uniformly grinding the heat-treated crystals, and preparing titanium dioxide and organic montmorillonite in a ratio of 1: 1 proportion of composite photocatalyst nano particles;

adding 0.25g of composite particles, 8.5g of 6010 polyvinylidene fluoride and 41.25g of N, N-dimethylacetamide into a container to dissolve and ultrasonically disperse for 25min, mechanically stirring for 12h at 60 ℃ after ultrasonic treatment, and standing and degassing for 4h to obtain a casting solution;

the casting solution was cast on a smooth glass plate, cast using a flat plate casting machine, and cast at a rate of 23 mm/S. And (3) placing the obtained membrane in water, changing the water once every 5.5 hours, and changing for 4 times to obtain the organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane.

The film was cut into 0.00070147m in area²The round is used for the experiment of degrading organic pollutants. The membrane was adsorbed in 20ml/g rhodamine, methyl blue for 30min, and a sample was taken for the original solution to test spectrophotometry. And (3) irradiating the adsorption-balanced membrane for 20min by using an ultraviolet lamp, taking part of the solution after the irradiation for testing the spectrophotometric value of the solution after photocatalysis, and calculating to obtain the three degradation efficiencies of the prepared 0.5wt% polymer membrane to 20ml/g methyl blue and rhodamine in 20min respectively as shown in table 1.

Example 4

The same procedure as in example 1 was repeated, except that the amount of the composite particles in example 1 was 0.5g, polyvinylidene fluoride 5g, and N, N-dimethylacetamide 44.5 g.

The film was cut into 0.00070147m in area²The round is used for the experiment of degrading organic pollutants. The membrane was adsorbed in 20ml/g rhodamine, methyl blue for 30min, and a sample was taken for the original solution to test spectrophotometry. And (3) irradiating the adsorption-balanced membrane for 20min by using an ultraviolet lamp, taking part of the solution after the irradiation for testing the spectrophotometric value of the solution after photocatalysis, and calculating to obtain the three degradation efficiencies of the prepared 1wt% polymer membrane to 20ml/g methyl blue and rhodamine in 20min respectively as shown in table 1.

Example 5

The same procedure as in example 1 was repeated, except that the amount of the composite particles in example 1 was 0.5g, that of polyvinylidene fluoride was 9.5g, and that of N, N-dimethylacetamide was 40 g.

The film was cut into 0.00070147m in area²The round is used for the experiment of degrading organic pollutants. The membrane was adsorbed in 20ml/g rhodamine, methyl blue for 30min, and a sample was taken for the original solution to test spectrophotometry. Irradiating the adsorption-balanced membrane with ultraviolet lamp for 20min, collecting part of the solution after the reaction, testing the spectrophotometric value of the solution after photocatalysis, and calculating to obtainWithin 20min, the three degradation efficiencies of the prepared 1wt% polymer film on 20ml/g methyl blue and rhodamine are respectively shown in Table 1.

Example 6

The same procedure as in example 1 was repeated, except that the amount of the composite particles in example 1 was 0.05g, polyvinylidene fluoride 5g, and N, N-dimethylacetamide 44.95 g.

The film was cut into 0.00070147m in area²The round is used for the experiment of degrading organic pollutants. The membrane was adsorbed in 20ml/g rhodamine, methyl blue for 30min, and a sample was taken for the original solution to test spectrophotometry. And (3) irradiating the adsorption-balanced membrane for 20min by using an ultraviolet lamp, taking part of the solution after the irradiation for testing the spectrophotometric value of the solution after photocatalysis, and calculating to obtain the three degradation efficiencies of the prepared 0.1wt% polymer membrane to 20ml/g Methyl Blue (MB) and Rhodamine (RHB) within 20min respectively as shown in Table 1.

Table 1 shows the results of the photocatalytic performance tests of commercially available PVDF and membranes made according to the invention on MB and RHB.

And (4) conclusion: from the above table, the photocatalyst particles are compounded into the organic montmorillonite/titanium dioxide polyvinylidene fluoride membrane, so that the contact area with the water body is increased, and the photocatalyst can be repeatedly used, so that the service life is prolonged. The invention has low cost of raw materials, so the manufacturing cost is low, and the popularization is facilitated.