阅读说明：本技术 一种超疏水豆渣纳米纤维素薄膜及清洁制备该薄膜的方法 (Super-hydrophobic bean dreg nanocellulose film and method for cleanly preparing same ) 是由 李佩燚 刘瑞岩 王雨萌 刘鹤震 雷镐哲 简博星 李新平 于 2020-11-24 设计创作，主要内容包括：一种超疏水豆渣纳米纤维素膜的制备工艺,豆渣过筛筛分出20-100目的豆渣粉；加入1-10%脂肪酶处理得纯豆渣；将氯化胆碱与草酸以摩尔比1：1-1：3混合,加入木糖酸,至均相透明液,成为三元低共熔溶剂DES；按照固液比1：10-1：40将纯豆渣加入DES,并加入催化剂,40-100℃搅拌加热处理20-60min,得到豆渣纤维素溶液；微波处理1-5min,再经5-20KHz超声处理2-6min,加水反析,离心分离得到纯豆渣纳米纤维素；将豆渣纳米纤维素加入5-15%的茁酶多糖和0.05-2%的蜂蜡,利用涂布法得到超疏水性豆渣纳米纤维素薄膜,水接触角可达到150°以上,并且具有一定抗甘油的性能。(A preparation method of superhydrophobic soybean residue nanometer cellulose membrane comprises sieving soybean residue to obtain 20-100 mesh soybean residue powder; adding 1-10% lipase to obtain pure bean dregs; choline chloride and oxalic acid are mixed in a molar ratio of 1: 1-1: 3, mixing, adding xylonic acid to obtain a homogeneous transparent liquid, and forming a ternary eutectic solvent DES; according to the solid-liquid ratio of 1: 10-1: 40 adding pure bean dregs into DES, adding a catalyst, stirring and heating at 40-100 ℃ for 20-60min to obtain a bean dreg cellulose solution; performing microwave treatment for 1-5min, performing 5-20KHz ultrasonic treatment for 2-6min, adding water, performing reverse precipitation, and centrifuging to obtain pure bean dregs nanocellulose; adding 5-15% of pullulanase polysaccharide and 0.05-2% of beeswax into bean dreg nanocellulose, and obtaining the super-hydrophobic bean dreg nanocellulose film by a coating method, wherein the water contact angle can reach more than 150 degrees, and the film has a certain glycerol resistance.)

1. A clean preparation method of a super-hydrophobic bean dreg nanocellulose film is characterized by comprising the following steps:

according to the solid-liquid ratio of 1: (10-40) adding pure bean dreg powder into the choline chloride-oxalic acid-xylonic acid ternary eutectic solvent, adding a catalyst, and fully stirring at 40-100 ℃ to obtain a bean dreg cellulose solution; performing microwave treatment on the bean dreg cellulose solution, then performing ultrasonic treatment, and adding water to perform cellulose reverse precipitation to obtain bean dreg nano-cellulose; adding pullulan 5-15% of the mass of the oven-dried bean dreg nanocellulose and beeswax 0.05-2% of the mass of the oven-dried bean dreg nanocellulose into the bean dreg nanocellulose, uniformly mixing, carrying out vacuum degassing, coating, and drying at 50-60 ℃ for 4-5 h; and (5) carrying out uniform wetting on the obtained film material, and uncovering the film to obtain the super-hydrophobic bean dreg nano cellulose film.

2. The method according to claim 1, wherein the molar ratio of choline chloride to oxalic acid in the choline chloride-oxalic acid-xylonic acid ternary eutectic solvent is 1: (1-3), wherein the molar ratio of oxalic acid to xylonic acid is 1: 1.5.

3. the method of claim 1, wherein the choline chloride-oxalic acid-xylonic acid ternary eutectic solvent is obtained by a method comprising: mixing choline chloride and oxalic acid, stirring at 40-100 ℃ for 10-20min, adding xylonic acid, and continuously stirring until the suspension becomes a homogeneous transparent liquid to obtain the ternary eutectic solvent.

4. The method as claimed in claim 1, wherein the catalyst is 0.05% -0.1% galactosidase relative to the mass of the oven dried bean dregs cellulose, and the enzyme activity content is 1000-3000U/g.

5. The method of claim 1, wherein when the soybean dreg cellulose solution is treated by microwave, millimeter wave of 30-300GHz is adopted for treatment for 1-5min, the size of the soybean dreg cellulose entering ultrasonic treatment is controlled to be 1-20 microns, and the molecular weight distribution is as uniform as possible; after the microwave treatment is finished, carrying out ultrasonic treatment on the bean dreg cellulose solution for 2-6min at 5-20KHz to obtain 10-100nm bean dreg nano-cellulose; and finally, adding water according to the ratio of 20-50ml/min, continuously stirring until all the cellulose is reversely precipitated, and centrifugally separating to obtain the pure bean dreg cellulose.

6. The method of claim 1, wherein the pure okara flour is obtained by a method comprising the steps of: sieving bean dregs to obtain 20-100 mesh bean dregs powder; adding 1-10% of lipase relative to the mass of the oven-dried bean dregs, adding a biological buffer solution to control the pH value to be 9-10, carrying out oil bath heating for 30-60min at a constant temperature of 30-60 ℃, inactivating in boiling water for 5-15min after the reaction is finished, and washing to be neutral to obtain the pure bean dregs.

7. The method of claim 6, wherein the biological buffer is glycine-Tris buffer.

8. The method of claim 1, wherein the pullulan has a number average molecular weight of 20000-30000 and the mass ratio of pullulan to beeswax is 100: 1.

9. The superhydrophobic okara nanocellulose film prepared by the method of any one of claims 1-8.

Technical Field

The invention belongs to the field of high-value utilization of natural polymers, and particularly relates to a clean preparation method of an agricultural waste super-hydrophobic bean dreg nanocellulose film.

Background

The nano-cellulose has the advantages of high strength, biocompatibility, degradability and the like, and is an ideal biomass material. However, the natural water absorption and moisture absorption characteristics limit the application fields of nanocellulose. Therefore, the construction of the nano-cellulose super-hydrophobic surface and the exploration of a green, environment-friendly, economical and efficient super-hydrophobic nano-cellulose film material which can be used for food packaging, electronic components and the like have important significance.

Disclosure of Invention

The invention aims to provide a clean, efficient and environment-friendly super-hydrophobic bean dreg nanocellulose film preparation process, bean dreg lipase treatment, galactosidase-catalyzed DES treatment and microwave-enhanced ultrasonic treatment are carried out to obtain bean dreg nanocellulose with stable performance and diameter of 10-100nm, pullulanase polysaccharide and beeswax are added into the obtained bean dreg nanocellulose, a coating method is adopted to obtain the super-hydrophobic bean dreg nanocellulose film, the water contact angle can reach more than 150 degrees, the film has certain glycerol resistance, the bean dreg is used as a raw material to prepare the super-hydrophobic nanocellulose film, and the preparation process is simple, efficient, green and environment-friendly.

In order to achieve the purpose, the invention adopts the technical scheme that:

step one, bean dregs pretreatment:

sieving bean dregs to obtain 20-100 mesh bean dregs powder; adding 1-10% (relative to the weight percentage of the oven-dried bean dregs) of lipase, adding a biological buffer solution to control the pH value to be 9-10, carrying out oil bath heating for 30-60min at a constant temperature of 30-60 ℃, inactivating in boiling water for 5-15min after the reaction is finished, and washing to be neutral to obtain pure bean dregs (removing fat in the bean dregs);

step two, synthesizing a ternary eutectic solvent (DES):

weighing choline chloride and oxalic acid in a molar ratio of 1: 1-1: 3, mixing, heating to 40-100 ℃ in an oil bath, magnetically stirring for 10-20min, adding a certain amount of xylonic acid, and continuously stirring for 10-20min until the suspension becomes a homogeneous transparent liquid to form a ternary eutectic solvent (DES) (the synthesized ternary eutectic solvent has stronger cellulose dissolving property, as shown in the following table 1, after being treated by the ternary eutectic solvent, the content of holocellulose reaches 98.24%, and the content of alpha-cellulose 95.43%) of the synthetic ternary eutectic solvent is obtained;

step three, treating bean dregs by using a eutectic solvent:

according to the solid-liquid ratio of 1: 10-1: 40, adding the bean dregs obtained in the step one into a ternary eutectic solvent (DES) synthesized in the step two, adding a catalyst, controlling the reaction temperature to be 40-100 ℃, and carrying out magnetic stirring and heating treatment for 20-60min to obtain a bean dreg cellulose solution;

step four: carrying out microwave reinforced ultrasonic treatment;

treating the bean dreg cellulose solution obtained in the step three in microwave for 1-5min, setting the ultrasonic frequency to be 5-20KHz, treating for 2-6min, adding water until all bean dreg nanocellulose is reversely precipitated, and performing centrifugal separation to obtain pure bean dreg nanocellulose;

step five: preparation of bean dreg cellulose film

Adding 5-15% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of pullulanase polysaccharide and 0.05-2% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of beeswax into the pure bean dreg nanocellulose in the fourth step, stirring for 5-10min, putting into a vacuum drying oven, degassing at 20-25 ℃ and the vacuum degree of 0.06-0.08MPa for 1-2 h; slowly coating a layer of uniform membrane liquid on a glass plate by using a coating rod, and drying for 4-5 hours in a constant-temperature drying box at 50-60 ℃; and (3) uniformly wetting the dried nano cellulose membrane for 4-5min at the pot mouth of a water bath kettle with higher relative humidity, uncovering the membrane to obtain the super-hydrophobic bean dreg nano cellulose membrane, wherein the water contact angle can reach more than 150 degrees, and the membrane has a certain glycerol resistance.

In a preferred embodiment of the present invention, the biological buffer in step one is glycine-Tris.

In a preferred embodiment of the present invention, the molar ratio of the oxalic acid to the xylonic acid in the second step is 1: 1.5.

In a preferred embodiment of the invention, the catalyst in the third step is 0.05-0.1% (mass percentage relative to the oven-dried bean dregs) galactosidase, and the enzyme activity content is 1000-3000U/g.

In a preferred embodiment of the invention, in the fourth step, under the condition of millimeter wave of 30-300GHz, the size of the bean dregs cellulose entering the ultrasonic treatment is controlled to be 1-20 microns, the molecular weight distribution is as uniform as possible, and the size of the finally obtained nano-cellulose can be reduced by 100-fold and 1000-fold compared with the size of the bean dregs cellulose before entering the ultrasonic treatment, so that the bean dregs nano-cellulose with the size of 10-100nm can be obtained. Slowly stirring, adding water, and back-separating, wherein the water adding speed is controlled at 20-50 ml/min.

In a preferred embodiment of the present invention, the molecular weight of pullulan in step 5 is 20000-30000, the amount of pullulan: beeswax dose =100: 1.

Through the technical scheme, the invention has the beneficial effects that:

after the bean dregs pass through the process, the super-hydrophobic bean dregs nano-cellulose film can be prepared, the preparation process is green, environment-friendly, energy-saving and consumption-reducing, the performance of the bean dregs nano-cellulose product is improved, the use field of the bean dregs nano-cellulose product is widened, the performance is stable, and the quality requirement of the nano-cellulose is met.

The bean dreg nano-cellulose film prepared by the invention not only changes waste into valuable and improves the added value of bean dreg products, but also provides a cleaner and more environment-friendly method for preparing the super-hydrophobic nano-cellulose film, and achieves the technical requirements of stable film performance, more than 150 degrees of water contact angle and certain glycerol resistance.

Detailed Description

The present invention is further described in order to make the technical means, the creation features, the achievement purposes and the effects of the present invention easy to understand.

The method for preparing the nano-cellulose film by utilizing the agricultural waste bean dregs not only meets the low-carbon economic development requirement, but also has certain practical significance for developing the research of nano-cellulose.

According to the specific component performance of the bean dregs (the cellulose content is as high as about 70%), the bean dregs cellulose dissolved and separated by the eutectic solvent is pure, the alpha-cellulose content is as high as 96.43%, the nano cellulose is directly prepared by microwave-assisted ultrasonic treatment (the treatment time is 5-10min, high-energy-consumption treatment such as high-pressure homogenization is not needed), the ultra-hydrophobic nano cellulose film is prepared by adding pullulan and beeswax, the production energy consumption is greatly reduced, and the used chemical additives are all green environment-friendly additives and have no environmental pollution.

Therefore, the nano-cellulose film is developed by taking waste bean dregs (the bean dregs are byproducts for producing bean products and are mainly used as feed or fertilizer at present) as raw materials, the high added value application of the bean dregs is promoted, and the industrial production of the bean dregs nano-cellulose product can be promoted.

A clean preparation process of a super-hydrophobic bean dreg nanocellulose film comprises the following steps:

step one, bean dregs pretreatment:

sieving bean dregs to obtain 20-100 mesh bean dregs powder; adding 1-10% (relative to the weight percentage of the oven-dried bean dregs) of lipase, adding a biological buffer solution to control the pH value to be 9-10, carrying out oil bath heating for 30-60min at a constant temperature of 30-60 ℃, inactivating in boiling water for 5-15min after the reaction is finished, and washing to be neutral to obtain pure bean dregs (removing fat in the bean dregs);

step two, synthesizing a ternary eutectic solvent (DES):

weighing choline chloride and oxalic acid in a molar ratio of 1: 1-1: 3, heating to 40-100 ℃ in an oil bath, magnetically stirring for 10-20min, adding a certain amount of xylonic acid, and continuously stirring for 10-20min until the suspension becomes homogeneous transparent liquid to become a ternary eutectic solvent (DES) (the synthesized ternary eutectic solvent has stronger cellulose dissolving property);

step three, treating bean dregs by using a eutectic solvent:

according to the solid-liquid ratio of 1: 10-1: 40, adding the bean dregs obtained in the step one into a ternary eutectic solvent (DES) synthesized in the step two, adding a catalyst, controlling the reaction temperature to be 40-100 ℃, and carrying out magnetic stirring and heating treatment for 20-60min to obtain a bean dreg cellulose solution;

in order to compare the actual effects of various eutectic solvents in processing bean dregs, choline chloride-glycerol (ChCl-G), choline chloride-urea (ChCl-U), choline chloride-oxalic acid (ChCl-O), choline chloride-citric acid (ChCl-C), sulfamic acid-urea (Sula-U) and the ternary eutectic solvent described in the application are compared, so that the yield of the bean dregs processed by various eutectic solvents, the components of the processed products and the like are shown in Table 1.

Note: choline chloride-glycerol (ChCl-G), choline chloride-urea (ChCl-U), choline chloride-oxalic acid (ChCl-O), choline chloride-citric acid (ChCl-C) and sulfamic acid-urea (Sula-U), wherein the yield = the oven-dried quality of the bean dregs after pretreatment/oven-dried quality of the bean dregs raw material, and the hemicellulose content = holocellulose-alpha-cellulose

The results shown in table 1 show that the choline chloride-oxalic acid-xylonic acid ternary eutectic solvent has the highest extraction efficiency on holocellulose in the bean dregs, the contents of protein, fat, ash and the like in the product are all the lowest, and the choline chloride-oxalic acid-xylonic acid ternary eutectic solvent has obvious advantages in the process of extracting cellulose in the bean dregs.

Step four: carrying out microwave reinforced ultrasonic treatment;

treating the bean dreg cellulose solution obtained in the step three in microwave for 1-5min, setting the ultrasonic frequency to be 5-20KHz, treating for 2-6min, adding water until all bean dreg nanocellulose is reversely precipitated, and performing centrifugal separation to obtain pure bean dreg nanocellulose;

step five: preparation of bean dreg cellulose film

Adding 5-15% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of pullulanase polysaccharide and 0.05-2% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of beeswax into the pure bean dreg nanocellulose in the fourth step, stirring for 5-10min, putting into a vacuum drying oven, degassing at 20-25 ℃ and the vacuum degree of 0.06-0.08MPa for 1-2 h; slowly coating a layer of uniform membrane liquid on a glass plate by using a coating rod, and drying for 4-5 hours in a constant-temperature drying box at 50-60 ℃; and (3) uniformly wetting the dried nano cellulose membrane for 4-5min at the pot mouth of a water bath kettle with higher relative humidity, uncovering the membrane to obtain the super-hydrophobic bean dreg nano cellulose membrane, wherein the water contact angle can reach more than 150 degrees, and the membrane has a certain glycerol resistance.

Further, the added biological buffer in the step one is glycine-Tris.

Further, the molar ratio of the oxalic acid to the xylonic acid in the second step is 1: 1.5.

Further, the catalyst in the third step is 0.05-0.1% (mass percentage relative to the dried bean dregs) of galactosidase, and the activity content of the added galactosidase is 1000-3000U/g.

Further, in the fourth step, the microwave treatment condition is 30-300GHz of millimeter waves, the size of the bean dreg cellulose entering the ultrasonic treatment is controlled to be 1-20 micrometers, the molecular weight distribution is uniform as much as possible, and the size of the finally obtained nano cellulose can be reduced by 100-fold and 1000-fold compared with the size of the bean dreg cellulose before the ultrasonic treatment, so that the bean dreg nano cellulose with the size of 10-100nm can be obtained.

Further, in the fifth step, the molecular weight of pullulan is 20000-30000, and the dosage of pullulan is as follows: beeswax dose =100: 1.

Example 1:

a clean preparation process of a super-hydrophobic bean dreg nanocellulose film comprises the following steps:

step one, bean dregs are sieved, and 40 meshes of bean dregs powder are sieved; adding 1% (by weight relative to oven-dried bean dregs) of lipase, adding biological buffer solution to control pH value at 9, heating in oil bath at constant temperature of 35 deg.C for 60min, inactivating in boiling water for 5min after reaction, and washing to neutrality to obtain pure bean dregs;

the added biological buffer is glycine-Tris.

Step two, weighing choline chloride and oxalic acid according to a molar ratio of 1: 1-1: 1, mixing, heating to 50 ℃ in an oil bath, magnetically stirring for 10min, adding a certain amount of xylonic acid, and continuously stirring for 20min until the suspension becomes a homogeneous transparent liquid to become a ternary eutectic solvent (DES);

the molar ratio of oxalic acid to xylonic acid is 1: 1.5.

Step three, adding the bean dregs obtained in the step one into the ternary eutectic solvent (DES) synthesized in the step two according to the solid-to-liquid ratio of 1:15, adding a catalyst, controlling the reaction temperature to be 40 ℃, and carrying out magnetic stirring and heating treatment for 50min to obtain a bean dreg cellulose solution;

adding the bean dregs obtained in the step one into a ternary eutectic solvent (DES) synthesized in the step two according to the solid-to-liquid ratio of 1:15, adding a catalyst, controlling the reaction temperature to be 40 ℃, and carrying out magnetic stirring and heating treatment for 90min to obtain a bean dreg cellulose solution;

the catalyst is 0.05% (mass percent relative to the oven-dried bean dregs) of galactosidase, and the enzyme activity content of the added galactosidase is 1500U/g.

Step four: treating the bean dreg cellulose solution obtained in the step three in microwave (100 GHz) for 2min, setting the ultrasonic frequency to be 15KHz, treating for 5min, adding water until all bean dreg nanocellulose is reversely precipitated, and performing centrifugal separation to obtain pure bean dreg nanocellulose;

step five: adding 15% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of pullulanase polysaccharide and 1.5% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of beeswax into the pure bean dreg nanocellulose in the fourth step, stirring for 10min, then placing the mixture into a vacuum drying box, degassing the mixture for 2h at the temperature of 25 ℃ and the vacuum degree of 0.08 MPa; slowly coating a layer of uniform membrane liquid on a glass plate by using a coating rod, putting the glass plate into a constant-temperature drying box at 60 ℃, and drying for 5 hours; and (3) uniformly wetting the dried nano cellulose membrane for 5min at the pot mouth of a water bath kettle with higher relative humidity, uncovering the membrane to obtain the super-hydrophobic bean dreg nano cellulose membrane, wherein the water contact angle can reach more than 150 degrees, and the membrane has a certain glycerol resistance.

Example 2:

a clean, high-efficiency and size-controllable preparation process of high-concentration nanocellulose of bean dregs comprises the following steps:

step one, bean dregs are sieved, and 70 meshes of bean dregs powder are sieved; adding 6% (by weight relative to the oven-dried bean dregs) of lipase, adding biological buffer solution to control pH value to 9.5, heating in oil bath at constant temperature of 5 deg.C for 45min, inactivating in boiling water for 7min after reaction, and washing to neutrality to obtain pure bean dregs;

the added biological buffer is glycine-Tris.

Step two, weighing choline chloride and oxalic acid according to a molar ratio of 1:1.5, heating to 80 ℃ in an oil bath, magnetically stirring for 15min, adding a certain amount of xylonic acid, and continuously stirring for 10min until the suspension becomes a homogeneous transparent liquid to form a ternary eutectic solvent (DES);

the molar ratio of oxalic acid to xylonic acid is 1: 1.5.

Step three, adding the bean dregs obtained in the step one into the ternary eutectic solvent (DES) synthesized in the step two according to the solid-to-liquid ratio of 1:30, adding a catalyst, controlling the reaction temperature to be 80 ℃, and carrying out magnetic stirring and heating treatment for 30min to obtain a bean dreg cellulose solution;

the catalyst is 0.07% (mass percent relative to the oven-dried bean dregs) of galactosidase, and the enzyme activity content of the added galactosidase is 2000U/g.

Step four: treating the bean dreg cellulose solution obtained in the step three in microwave (150 GHz) for 4min, setting the ultrasonic frequency to be 18KHz, treating for 3min, adding water until all bean dreg nanocellulose is reversely precipitated, and performing centrifugal separation to obtain pure bean dreg nanocellulose;

step five: adding 10% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of pullulanase polysaccharide and 1% (relative to the mass percent of the oven-dried bean dreg nanocellulose) of beeswax into the pure bean dreg nanocellulose in the fourth step, stirring for 8min, then placing into a vacuum drying box, degassing the mixture for 1.5h at the temperature of 22 ℃ and the vacuum degree of 0.07 MPa; slowly coating a layer of uniform membrane liquid on a glass plate by using a coating rod, putting the glass plate into a constant-temperature drying box at 55 ℃, and drying for 4.5 hours; and (3) uniformly wetting the dried nano cellulose membrane for 4.5min at the pot mouth of the water bath kettle with higher relative humidity, uncovering the membrane to obtain the super-hydrophobic bean dreg nano cellulose membrane, wherein the water contact angle can reach more than 150 degrees, and the membrane has a certain glycerol resistance.

Example 3:

a clean, high-efficiency and size-controllable preparation process of high-concentration nanocellulose of bean dregs comprises the following steps:

firstly, sieving bean dregs to obtain 80-mesh bean dreg powder; adding 8% (by weight relative to the oven-dried bean dregs) of lipase, adding a biological buffer solution to control the pH value to be 9.5, carrying out oil bath heating for 30min at a constant temperature of 55 ℃, inactivating in boiling water for 10min after the reaction is finished, and washing to be neutral to obtain pure bean dregs;

the added biological buffer is glycine-Tris.

Step two, weighing choline chloride and oxalic acid according to a molar ratio of 1:3, heating to 70 ℃ in an oil bath, magnetically stirring for 20min, adding a certain amount of xylonic acid, and continuously stirring for 10min until the suspension becomes a homogeneous transparent liquid to become a ternary eutectic solvent (DES);

the molar ratio of the added oxalic acid to the added xylonic acid is 1: 1.5.

Step three, adding the bean dregs obtained in the step one into the ternary eutectic solvent (DES) synthesized in the step two according to the solid-to-liquid ratio of 1:20, adding a catalyst, controlling the reaction temperature to be 75 ℃, and carrying out magnetic stirring and heating treatment for 40min to obtain a bean dreg cellulose solution;

the catalyst is 0.08% (mass percent relative to the oven-dried bean dregs) of galactosidase, and the enzyme activity content of the added galactosidase is 3000U/g.

Step four: treating the bean dreg cellulose solution obtained in the step three in microwave (200 GHz) for 3min, setting the ultrasonic frequency to be 12KHz, treating for 3min, adding water until all bean dreg nanocellulose is reversely precipitated, and performing centrifugal separation to obtain pure bean dreg nanocellulose;

step five: adding 5 percent of pullulanase polysaccharide relative to the mass percent of the oven-dried bean dreg nanocellulose) and 0.05 percent of beeswax relative to the mass percent of the oven-dried bean dreg nanocellulose) into the pure bean dreg nanocellulose in the fourth step, stirring for 5min, putting the mixture into a vacuum drying box, and degassing the mixture for 1h at the temperature of 20 ℃ and the vacuum degree of 0.06 MPa; slowly coating a layer of uniform membrane liquid on a glass plate by using a coating rod, putting the glass plate into a constant-temperature drying box at 50 ℃, and drying for 4 hours; and (3) uniformly wetting the dried nano cellulose membrane for 4min at the pot mouth of a water bath kettle with higher relative humidity, uncovering the membrane to obtain the super-hydrophobic bean dreg nano cellulose membrane, wherein the water contact angle can reach more than 150 degrees, and the membrane has a certain glycerol resistance.