阅读说明：本技术 一种淀粉基疏水纸、其制备方法及应用 (Starch-based hydrophobic paper, and preparation method and application thereof ) 是由 张帆 于 2021-09-22 设计创作，主要内容包括：本发明涉及功能材料技术领域,尤其涉及一种淀粉基疏水纸、其制备方法及应用。所述淀粉基疏水纸的制备方法包括：A)将纸材料与N,N-二甲基乙酰胺搅拌混合,得到纸浆；将改性淀粉、疏水二氧化硅粒子和N,N-二甲基乙酰胺混合,得到改性淀粉溶液；B)将所述改性淀粉溶液和所述纸浆搅拌混合,得到混合浆液；C)将所述混合浆液与戊二醛溶液搅拌混合,抽滤后,得到淀粉基疏水纸。所述淀粉基疏水纸作为油水分离材料适用于油包水乳液的破乳分离,并且可以获得较高的油水分离效率。本发明以淀粉和二氧化硅为添加剂,即可降低原料成本,又可使制备的分离膜具有生物降解性,且淀粉可再生,来源广泛,便于分离膜的大规模生产和应用。(The invention relates to the technical field of functional materials, in particular to starch-based hydrophobic paper, and a preparation method and application thereof. The preparation method of the starch-based hydrophobic paper comprises the following steps: A) stirring and mixing the paper material and N, N-dimethylacetamide to obtain paper pulp; mixing modified starch, hydrophobic silicon dioxide particles and N, N-dimethylacetamide to obtain a modified starch solution; B) stirring and mixing the modified starch solution and the paper pulp to obtain mixed slurry; C) and stirring and mixing the mixed slurry and a glutaraldehyde solution, and performing suction filtration to obtain the starch-based hydrophobic paper. The starch-based hydrophobic paper as an oil-water separation material is suitable for demulsification separation of water-in-oil emulsion, and can obtain higher oil-water separation efficiency. The invention takes starch and silicon dioxide as additives, which not only can reduce the cost of raw materials, but also can lead the prepared separation membrane to have biodegradability, and the starch is renewable, has wide sources, and is convenient for large-scale production and application of the separation membrane.)

1. A preparation method of starch-based hydrophobic paper comprises the following steps:

A) stirring and mixing the paper material and N, N-dimethylacetamide to obtain paper pulp;

mixing modified starch, hydrophobic silicon dioxide particles and N, N-dimethylacetamide to obtain a modified starch solution;

B) mixing the modified starch solution and the paper pulp to obtain mixed slurry;

C) and stirring and mixing the mixed slurry and a glutaraldehyde solution, and performing suction filtration to obtain the starch-based hydrophobic paper.

2. The method according to claim 1, wherein in the step a), the mass ratio of the paper material to the N, N-dimethylacetamide in the pulp is 1: 50 to 100.

3. The preparation method according to claim 1, wherein in the modified starch solution in the step A), the mass ratio of the modified starch to the hydrophobic silica particles to the N, N-dimethylacetamide is 0.2-1: 0.2-0.75: 50.

4. the method according to claim 1, wherein in step a), the modified starch is prepared by the following method:

carrying out esterification reaction on starch, palmitoyl chloride and perfluorodecyl triethoxysilane at 75-85 ℃ to obtain modified starch.

5. The method according to claim 4, wherein the molar ratio of the starch, palmitoyl chloride, and perfluorodecanoyl triethoxysilane is 1: 1.5-4: 0.5 to 1.5;

after the esterification reaction, the method further comprises the following steps:

precipitating with deionized water, filtering, cleaning, and oven drying.

6. The method according to claim 1, wherein the step B) of agitating and mixing the modified starch solution and the pulp comprises:

adding the modified starch solution into the stirred paper pulp, and continuously stirring for a period of time;

the time for continuously stirring is 12-24 h.

7. The preparation method according to claim 1, wherein in the step C), the mass concentration of the glutaraldehyde solution is 5-15%;

the pH value of the glutaraldehyde solution is 1-3.

8. The method according to claim 1, wherein in step C), the volume ratio of the mixed slurry to the glutaraldehyde solution is 1: 0.2 to 1.

9. The starch-based hydrophobic paper prepared by the preparation method of any one of claims 1 to 8.

10. Use of the starch-based hydrophobic paper as claimed in claim 9 as a material for oil and water separation.

Technical Field

The invention relates to the technical field of functional materials, in particular to starch-based hydrophobic paper, and a preparation method and application thereof.

Background

The paper material is a green material taking plant fiber as a main raw material, has the characteristics of both flexible materials and rigid materials, and plays an important role in social and economic construction and human daily life. The paper material itself has micron-sized pores formed by interweaving fibers and fiber layers, and thus becomes a common base material for many separation materials. However, cellulose and hemicellulose, which are main components of paper, have a large number of hydrophilic hydroxyl groups, so that the paper has super-strong hydrophilicity and is very easy to absorb water, swell and damage, and the application of the paper in the field of oil-water separation is limited. In order to overcome the defects of paper caused by water absorption and expand the application field of the paper, the inherent hydrophilicity of the paper is firstly changed, and the paper is endowed with stable hydrophobicity; in addition, a hierarchical micro-nano structure is required to be constructed on the surface of the water-in-oil emulsion to further amplify the wettability of the water-in-oil emulsion, so that the water-in-oil emulsion can obtain stable oil superhydrophobicity and can be applied to demulsification and separation of the water-in-oil emulsion.

Currently, methods for making hydrophobic paper are commonly used, surface sizing paper making and internal sizing paper making. The hydrophobic paper prepared by the surface sizing method has higher requirements on equipment, and the uneven distribution of the sizing agent easily causes uneven surface mechanical property and hydrophobic distribution. Internal sizing paper manufacture is therefore the primary method of making hydrophobic paper. The internal sizing agent mainly comprises a rosin sizing agent, a synthetic sizing agent and a paraffin sizing agent. The sizing agents have both hydrophilic groups and hydrophobic groups in terms of chemical structure, can be firmly attached to the surfaces of paper fibers, and completely wrap each independent paper fiber like a film. The paper prepared by the method has greatly improved hydrophobicity and mechanical strength, but the demulsification and separation of the water-in-oil emulsion are difficult to realize due to the lack of assistance of a layered micro-nano structure. Therefore, a layered micro-nano structure is constructed on the paper material, unique wettability is given, and the development of the application of the paper material in the field of oil-water separation becomes a research hotspot at present.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a starch-based hydrophobic paper, a preparation method and an application thereof, which are suitable for demulsification and separation of water-in-oil emulsion.

The invention provides a preparation method of starch-based hydrophobic paper, which comprises the following steps:

A) stirring and mixing the paper material and N, N-dimethylacetamide to obtain paper pulp;

mixing modified starch, hydrophobic silicon dioxide particles and N, N-dimethylacetamide to obtain a modified starch solution;

B) mixing the modified starch solution and the paper pulp to obtain mixed slurry;

C) and stirring and mixing the mixed slurry and a glutaraldehyde solution, and performing suction filtration to obtain the starch-based hydrophobic paper.

Preferably, in step a), the mass ratio of the paper material to the N, N-dimethylacetamide in the pulp is 1: 50 to 100.

Preferably, in the step a), in the modified starch solution, the mass ratio of the modified starch to the hydrophobic silica particles to the N, N-dimethylacetamide is 0.2-1: 0.2-0.75: 50.

preferably, in step a), the modified starch is prepared according to the following method:

carrying out esterification reaction on starch, palmitoyl chloride and perfluorodecyl triethoxysilane at 75-85 ℃ to obtain modified starch.

Preferably, the molar ratio of the starch, the palmitoyl chloride and the perfluorodecyl triethoxysilane is 1: 1.5-4: 0.5 to 1.5;

after the esterification reaction, the method further comprises the following steps:

precipitating with deionized water, filtering, cleaning, and oven drying.

Preferably, in the step B), the mixing the modified starch solution and the pulp with stirring comprises:

adding the modified starch solution into the stirred paper pulp, and continuously stirring for a period of time;

the time for continuously stirring is 12-24 h.

Preferably, in the step C), the mass concentration of the glutaraldehyde solution is 5-15%;

the pH value of the glutaraldehyde solution is 1-3.

Preferably, in the step C), the volume ratio of the mixed slurry to the glutaraldehyde solution is 1: 0.2 to 1.

The invention also provides starch-based hydrophobic paper prepared by the preparation method.

The invention also provides application of the starch-based hydrophobic paper as an oil-water separation material.

The invention provides a preparation method of starch-based hydrophobic paper, which comprises the following steps: A) stirring and mixing the paper material and N, N-dimethylacetamide to obtain paper pulp; mixing modified starch, hydrophobic silicon dioxide particles and N, N-dimethylacetamide to obtain a modified starch solution; B) stirring and mixing the modified starch solution and the paper pulp to obtain mixed slurry; C) and stirring and mixing the mixed slurry and a glutaraldehyde solution, and performing suction filtration to obtain the starch-based hydrophobic paper. The starch-based hydrophobic paper as an oil-water separation material is suitable for demulsification separation of water-in-oil emulsion, and can obtain higher oil-water separation efficiency. In addition, the invention takes starch and silicon dioxide as additives, which not only can reduce the cost of raw materials, but also can lead the prepared separation membrane to have biodegradability, and the starch is renewable and has wide source, thereby being convenient for the large-scale production and application of the separation membrane.

Drawings

FIG. 1 is an SEM image of base paper of example 1 of the present invention;

FIG. 2 is an SEM image of a starch-based hydrophobic paper of example 1 of the present invention;

FIG. 3 is an enlarged view of FIG. 2 of the present invention;

FIG. 4 is a n-hexane contact angle test chart of the starch-based hydrophobic paper of example 1 of the present invention in air;

FIG. 5 is a water drop contact angle test chart of starch-based hydrophobic paper of example 1 of the present invention in air;

FIG. 6 is a water drop contact angle test chart of starch-based hydrophobic paper in n-hexane according to example 1 of the present invention;

FIG. 7 is an SEM image of a starch-based hydrophobic paper of comparative example 1 of the present invention;

FIG. 8 is a diagram showing an apparatus for separating oil and water according to example 8 of the present invention using starch-based hydrophobic paper.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a preparation method of starch-based hydrophobic paper, which comprises the following steps:

A) stirring and mixing the paper material and N, N-dimethylacetamide to obtain paper pulp;

mixing modified starch, hydrophobic silicon dioxide particles and N, N-dimethylacetamide to obtain a modified starch solution;

B) stirring and mixing the modified starch solution and the paper pulp to obtain mixed slurry;

C) and stirring and mixing the mixed slurry and a glutaraldehyde solution, and performing suction filtration to obtain the starch-based hydrophobic paper.

The paper material and N, N-dimethylacetamide are stirred and mixed to obtain paper pulp.

In certain embodiments of the present invention, the paper material is base paper.

In certain embodiments of the present invention, the mass ratio of paper material to N, N-dimethylacetamide in the pulp is 1: 50 to 100. In certain embodiments, the mass ratio of paper material to N, N-dimethylacetamide in the pulp is 1: 50.

in certain embodiments of the present invention, the paper material is mixed with N, N-dimethylacetamide with stirring at room temperature.

The modified starch solution is obtained by mixing modified starch, hydrophobic silicon dioxide particles and N, N-dimethylacetamide.

In certain embodiments of the present invention, in the modified starch solution, the mass ratio of the modified starch to the hydrophobic silica particles to the N, N-dimethylacetamide is 0.2 to 1: 0.2-0.75: 50. in certain embodiments, the modified starch solution has a mass ratio of modified starch, hydrophobic silica particles, and N, N-dimethylacetamide of 0.5: 0.2-0.75: 50. in certain embodiments, the modified starch solution has a mass ratio of modified starch, hydrophobic silica particles, and N, N-dimethylacetamide of 0.5: 0.3: 50. 0.5: 0.2: 50. 0.5: 0.5: 50 or 0.5: 0.75: 50.

in certain embodiments of the invention, the modified starch is prepared according to the following method:

carrying out esterification reaction on starch, palmitoyl chloride and perfluorodecyl triethoxysilane at 75-85 ℃ to obtain modified starch.

In certain embodiments of the invention, the starch, palmitoyl chloride, and perfluorodecanoyl triethoxysilane are present in a molar ratio of 1: 1.5-4: 0.5 to 1.5. In certain embodiments, the starch, palmitoyl chloride, and perfluorodecanoyl triethoxysilane are present in a molar ratio of 1: 3: 0.6.

in certain embodiments of the present invention, the temperature of the esterification reaction is 80 ℃. In certain embodiments of the present invention, the esterification reaction time is 3 to 5 hours. In certain embodiments, the esterification reaction time is 5 hours.

In certain embodiments of the present invention, after the esterification reaction, further comprising:

precipitating with deionized water, filtering, cleaning, and oven drying.

In some embodiments of the invention, the number of times of the suction filtration and cleaning is 2-3 times. In certain embodiments, the number of pump rinse cycles is 2.

The steps of suction filtration cleaning and drying are not particularly limited in the present invention, and those known to those skilled in the art can be used.

And after obtaining the modified starch solution, stirring and mixing the modified starch solution and the paper pulp to obtain mixed slurry.

In certain embodiments of the present invention, agitating and mixing the modified starch solution and the pulp comprises: adding the modified starch solution to the stirred pulp, and continuing stirring for a period of time.

In some embodiments of the invention, the stirring is continued for 12-24 hours. In certain embodiments, the stirring is continued for 24 hours.

The method of stirring and mixing is not particularly limited in the present invention, and a method of stirring and mixing known to those skilled in the art may be used.

And after mixed slurry is obtained, stirring and mixing the mixed slurry and a glutaraldehyde solution, and performing suction filtration to obtain the starch-based hydrophobic paper.

In certain embodiments of the present invention, the agitation mixing of the mixed slurry with the glutaraldehyde solution comprises: adding glutaraldehyde solution to the mixed slurry under stirring, and continuing stirring for a while.

In some embodiments of the invention, the stirring is continued for 12-24 hours. In certain embodiments, the stirring is continued for 24 hours.

In the invention, the glutaraldehyde solution is a cross-linking agent. In certain embodiments of the invention, the glutaraldehyde solution has a mass concentration of 5% to 15%. In certain embodiments, the glutaraldehyde solution has a mass concentration of 10%. In certain embodiments of the invention, the glutaraldehyde solution has a pH of 1 to 3. In certain embodiments, the glutaraldehyde solution has a pH of 1. In certain embodiments of the invention, the volume ratio of the mixed slurry to the glutaraldehyde solution is 1: 0.2 to 1. In certain embodiments, the volume ratio of the mixed slurry to the glutaraldehyde solution is 1: 0.2.

the method of suction filtration is not particularly limited in the present invention, and a method of suction filtration known to those skilled in the art may be used.

In certain embodiments of the present invention, after the suction filtration, drying is further included.

In certain embodiments of the present invention, the drying may be oven drying, to a constant weight.

The invention also provides starch-based hydrophobic paper prepared by the preparation method.

The invention also provides application of the starch-based hydrophobic paper as an oil-water separation material. The starch-based hydrophobic paper is used as an oil-water separation material to perform demulsification separation of water-in-oil emulsion, so that higher oil-water separation efficiency can be obtained. Thus, the applicant claims the use of said starch-based hydrophobic paper as oil-water separation material.

The source of the above-mentioned raw materials is not particularly limited in the present invention, and may be generally commercially available.

In order to further illustrate the present invention, the following detailed description of a starch-based hydrophobic paper, its preparation method and application are provided in connection with the examples, which should not be construed as limiting the scope of the present invention.

The starting materials used in the following examples are all commercially available.

Example 1

1) Adding 1g of base paper into 50g N, N-dimethylacetamide, and stirring at room temperature to obtain uniform paper pulp;

2) carrying out esterification reaction on 1g (0.005mol) of starch, 4.5g (0.015mol) of palmitoyl chloride and 2g (0.003mol) of perfluorodecyl triethoxysilane at 80 ℃ for 5h, precipitating with deionized water, carrying out suction filtration and cleaning for 2 times, and drying to obtain modified starch TOHTES-PC-St;

3) dispersing 0.5g of modified starch TOHTES-PC-St and 0.3g of hydrophobic silica particles with 50g N, N-dimethylacetamide to obtain a modified starch solution;

4) adding the modified starch solution into the stirred paper pulp, and continuously stirring for 24 hours to obtain mixed slurry;

5) adding a glutaraldehyde solution with the pH value of 1 and the mass concentration of 10% into the mixed slurry, wherein the volume ratio of the mixed slurry to the glutaraldehyde solution is 1: 0.2, continuously stirring for 24 hours to ensure that the additive and the paper fiber are fully crosslinked;

6) and finally, removing the redundant solvent by suction filtration, and drying the obtained paper in an oven to constant weight to obtain the starch-based hydrophobic paper.

In this example, the raw paper was analyzed by scanning electron microscopy, and the results are shown in FIG. 1. FIG. 1 is an SEM image of base paper of example 1 of the present invention.

In this example, the obtained starch-based hydrophobic paper was analyzed by scanning electron microscopy, and the results are shown in fig. 2. Fig. 2 is an SEM image of starch-based hydrophobic paper of example 1 of the present invention. Fig. 3 is an enlarged view of fig. 2 of the present invention. As can be seen from fig. 3, a plurality of fibers are interlaced to form a micron-sized pore channel, and the hydrophobic silica nanoparticles uniformly wrap each fiber, so that a layered micro-nano structure is successfully constructed on the surface of the paper.

In this example, the obtained starch-based hydrophobic paper was subjected to a contact angle test of oil droplets (n-hexane) in air, the starch-based hydrophobic paper was fixed on a glass slide with a double-sided tape, and a 2 μ L drop of n-hexane was dropped on the surface of the paper with a contact angle measuring instrument, with the result shown in fig. 4. FIG. 4 is a n-hexane contact angle test chart of the starch-based hydrophobic paper of example 1 of the present invention in air. As can be seen from FIG. 4, in the air, the n-hexane contact angle of the starch-based hydrophobic paper is 34.3 degrees, and the starch-based hydrophobic paper has excellent oleophylic property.

In this example, the starch-based hydrophobic paper obtained was subjected to a contact angle test of a water drop in air, the starch-based hydrophobic paper was fixed on a glass slide with a double-sided tape, and a 2. mu.L drop of water was dropped on the surface of the paper with a contact angle measuring apparatus, and the result is shown in FIG. 5. FIG. 5 is a water drop contact angle test chart of the starch-based hydrophobic paper of example 1 of the present invention in air. As can be seen from FIG. 5, the contact angle of the starch-based hydrophobic paper in air is 136.8 degrees, and the starch-based hydrophobic paper has excellent hydrophobic property.

In this example, the obtained starch-based hydrophobic paper was subjected to a contact angle test of a water droplet in n-hexane, the starch-based hydrophobic paper was fixed on a glass slide with a double-sided tape and placed in a small box containing n-hexane, and a 2 μ L droplet of water was dropped on the surface of the paper with a contact angle measuring instrument, with the result shown in fig. 6. FIG. 6 is a water drop contact angle test chart of the starch-based hydrophobic paper of example 1 of the present invention in n-hexane. As can be seen from fig. 6, in n-hexane, the starch-based hydrophobic paper has a water droplet contact angle of 165.5 °, and has an oily superhydrophobicity.

Comparative example 1

1) Adding 1g of base paper into 50g N, N-dimethylacetamide, and stirring at room temperature to obtain uniform paper pulp;

2) carrying out esterification reaction on 1g of starch, 4.5g of palmitoyl chloride and 2g of perfluorodecyl triethoxysilane at 80 ℃ for 5h, precipitating with deionized water, carrying out suction filtration and cleaning for 2 times, and drying to obtain modified starch TOHTES-PC-St;

3) dissolving 0.5g of modified starch TOHTES-PC-St with 50g N, N-dimethylacetamide to obtain a modified starch solution;

4) adding the modified starch solution into the paper pulp, and continuously stirring and mixing for 24 hours to obtain mixed slurry;

5) adding 50mL of 10% glutaraldehyde solution with the pH of 1 into the mixed slurry, and continuing stirring for 24 hours to fully crosslink the additive and the paper fibers;

6) and finally, removing the redundant solvent by suction filtration, and drying the obtained paper in an oven to constant weight to obtain the starch-based hydrophobic paper.

In the comparative example, the obtained starch-based hydrophobic paper was analyzed by scanning electron microscopy, and the result is shown in fig. 7. Fig. 7 is an SEM image of the starch-based hydrophobic paper of comparative example 1 of the present invention. As can be seen from FIG. 7, the hydrophobically modified starch tightly wraps every fiber due to its good compatibility with paper fibers, and the fiber surface becomes smooth and flat.

Comparative example 2

The difference from comparative example 1 is that modified starch TOHTES-PC-St was used in an amount of 0.2g in step 3) to obtain starch-based hydrophobic paper.

Comparative example 3

The difference from comparative example 1 is that modified starch TOHTES-PC-St was used in an amount of 0.75g in step 3) to obtain starch-based hydrophobic paper.

Comparative example 4

The difference from comparative example 1 is that in step 3), the modified starch TOHTES-PC-St was used in an amount of 1g, resulting in a starch-based hydrophobic paper.

Example 2

The difference from example 1 is that in step 3), the amount of hydrophobic silica particles was 0.2g, and starch-based hydrophobic paper was obtained.

Example 3

The difference from example 1 is that in step 3), the amount of hydrophobic silica particles was 0.5g, and starch-based hydrophobic paper was obtained.

Example 4

The difference from example 1 is that in step 3), the amount of hydrophobic silica particles was 0.75g, and starch-based hydrophobic paper was obtained.

Water contact angle in air (WCA), water contact angle in oil (UOWCA) test for starch-based hydrophobic paper:

in accordance with the contact angle test method of example 1, this example shows the results of the water drop contact angle test (WCA) in air for the starch-based hydrophobic papers of examples 1-4 and comparative examples 1-4, and the results of the water drop contact angle test (UOWCA) in n-hexane for the starch-based hydrophobic papers of examples 1-4 and comparative examples 1-4, as shown in Table 1.

Water-in-oil emulsion separation efficiency (R) and separation flux (F) test:

starch-based hydrophobic paper was placed between two glassware vessels (as shown in FIG. 8, FIG. 8 is an oil-water separation apparatus using starch-based hydrophobic paper according to the present invention, example 8, Span80 as a surfactant was added to water in an amount of 3% by weight, and the mixture was emulsified with toluene at a volume ratio of 10: 90 to prepare a water-in-oil emulsion, the emulsion was poured into the apparatus shown in FIG. 8 for separation, the water content of the filtrate was analyzed by a Karl moisture meter, the separation efficiency R was calculated according to formula (1), and the separation flux F was calculated according to formula (2), and the results are shown in Table 1.

Separation efficiency R (%) - (1-C)_p/C₀)×100％ (1)；

In the formula (1), C₀: water content before separation,%; c_p: water content in the separated filtrate is percent.

Separation flux F (L/m)²·h)＝V/(A·T) (2)；

In formula (2), V: volume of filtrate after separation, L; a: effective separation area of paper material, m²(ii) a T is the separation time h.

TABLE 1 Water-in-air contact Angle (WCA), Water-under-oil contact Angle (UOWCA), Water-in-oil emulsion separation efficiency (R) and separation flux (F) for starch-based hydrophobic papers of examples 1-4

The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.