A super-hydrophobic anti-static microporous membrane based on a modified microfibrillated cellulose framework, a preparation method and applications

Abstract

The application discloses a preparation method of a super-hydrophobic antistatic microporous membrane based on a modified microfibrillated cellulose framework, wherein microfibrillated cellulose is modified to obtain hydroxyapatite modified microfibrillated cellulose, which is further self-assembled with a conductive substance to form an interlaced cellulose framework, so that the oil-water separation flux is greatly improved; the self-assembly with the conductive substance also endows the microporous membrane with antistatic property, and the surface resistivity is less than 10 11 Ω; the microporous membrane prepared by compounding with polydimethylsiloxane has super-hydrophobic property, and the surface water contact angle is more than 150°; the super-hydrophobic antistatic microporous membrane prepared based on the method has excellent oil-water separation flux and oil-water separation efficiency, and has high stability, so that the wide application of the oil-water separation technology is promoted.

Description

Technical Field

[0001] This invention relates to the field of oil-water separation technology, specifically to a superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework, its preparation method, and its application. Background Technology

[0002] With the rapid development of modern society, various industries and daily life generate large amounts of oily wastewater, causing serious ecological damage and endangering human survival. Therefore, the research and development of efficient oil-water separation technologies is particularly important. Compared with traditional separation methods such as sedimentation, centrifugation, and adsorption, membrane separation has attracted widespread attention due to its advantages such as simple operation, high separation efficiency, low energy consumption, and environmental friendliness.

[0003] An ideal oil-water separation membrane should possess high separation efficiency, high flux, excellent oil-water affinity and selectivity, and outstanding stability and repeatability. In current research, numerous researchers are dedicated to exploring and developing various materials, including metals, inorganic materials, and organic materials, to fabricate high-performance oil-water separation membranes. These membrane materials have demonstrated separation efficiencies exceeding 99% under laboratory conditions, showing enormous application potential.

[0004] However, the preparation processes of existing membrane materials typically involve complex modification steps, such as layer-by-layer self-assembly techniques. While these techniques allow for precise control of membrane structure and performance, the complexity and difficulty of the preparation process cannot be ignored. Furthermore, achieving high-throughput preparation of these high-performance separation membranes also faces significant challenges. More critically, the preparation processes of many membrane materials inevitably use fluorinated compounds, which not only pose a potential threat to environmental safety but also severely limits the feasibility of these oil-water separation membranes in large-scale production and commercial applications.

[0005] Cellulose has been widely used as a superhydrophobic modification matrix in previous reports. As a widely available, biodegradable, renewable, and environmentally friendly material, cellulose possesses hydrophilicity, excellent toughness, high strength, and a large fiber aspect ratio. Therefore, superhydrophobic modification of cellulose can be used for oil-water separation. Compared to traditional membranes, superhydrophobic cellulose membranes can minimize waste generated through biodegradation. Furthermore, the pore structure of superhydrophobic cellulose membranes enables efficient oil-water separation with high selectivity and permeability.

[0006] Existing technology application CN116585898A discloses a cellulose / polyvinylidene fluoride electrospun oil-water separation membrane and its preparation method. The method involves preparing cellulose stearoyl ester and polyvinylidene fluoride separately into solutions, then mixing them to obtain a spinning solution. After degassing the spinning solution, electrospinning is performed to obtain a hydrophobic and oleophilic cellulose stearoyl ester / polyvinylidene fluoride oil-water separation membrane. Cellulose acts as a reinforcing agent in electrospinning to improve the mechanical properties of the material; however, the use of fluorine-containing compounds can cause environmental pollution.

[0007] For example, invention application CN114832647A discloses a method for preparing and applying a temperature-sensitive switchable emulsion-type oil-water separation membrane. This method utilizes cellulose nanofibers (CNF) to increase the porosity between MnO2 nanowires, uses PVDF to increase the membrane's toughness, and grafts poly(N-isopropylacrylamide) (PNIPAM) to achieve a temperature-sensitive, switchable wettability composite membrane. The oil-water separation membrane obtained through this method has high mechanical properties, but the preparation process is cumbersome and time-consuming.

[0008] The invention application with publication number CN116510533A discloses a method for preparing a waste biomass-based Janus oil-water separation membrane and its application in emulsion separation. The method uses waste biomass cellulose as a substrate, modifies it with dopamine to obtain a polydopamine / cellulose membrane, and then electrospun polyethylene terephthalate on the surface to form a Janus membrane with asymmetric wetting properties, which realizes the efficient utilization of biomass resources. However, the stability during use still needs to be verified.

[0009] Currently, the following technical challenges exist in the field of oil-water separation technology: slow separation efficiency, low throughput, poor oil-water separation cycle performance, and the cumbersome process of preparing oil-water separation membrane materials, which can cause secondary pollution to the environment due to processing residues. Therefore, developing a superhydrophobic cellulose membrane with high stability, high throughput, and high separation efficiency for oil-water separation applications to promote the widespread application and commercialization of oil-water separation technology is an urgent problem to be solved. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides a superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework, its preparation method, and its application. By modifying microfibrillated cellulose to improve its hydrophobicity and conductivity, a cellulose microporous membrane with high stability, high flux, and high separation efficiency is prepared for oil-water separation.

[0011] A method for preparing a superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework includes the following steps:

[0012] (1) Microfibrillated cellulose, calcium salt, sodium hydroxide and phosphate were added to a mixed solution of oleic acid and anhydrous ethanol and subjected to a solvothermal reaction. The microfibrillated cellulose modified with hydroxyapatite was obtained by centrifugation and filtration.

[0013] (2) The hydroxyapatite-modified microfibrillated cellulose prepared in step (1) is ultrasonically mixed with a conductive substance in anhydrous ethanol, and then filtered and dried to obtain an antistatic microporous membrane based on the modified microfibrillated cellulose framework.

[0014] (3) The antistatic microporous membrane based on the modified microfibrillated cellulose framework obtained in step (2) is immersed in polydimethylsiloxane diluted with ethyl acetate. The immersed antistatic microporous membrane is then dried to obtain a superhydrophobic antistatic microporous membrane based on the modified microfibrillated cellulose framework.

[0015] This invention is based on the modification of microfibrillated cellulose to achieve three-dimensional fiber assembly, and combines carbon nanotubes and low surface energy materials to further improve hydrophobicity and conductivity, thereby obtaining a superhydrophobic cellulose microporous membrane with high throughput and high separation efficiency.

[0016] Preferably, the calcium salt is one or more selected from calcium nitrate, calcium hydroxide, calcium hydrogen phosphate, calcium oxide, and calcium chloride;

[0017] The phosphate is one or more of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate, phosphoric acid, and diammonium hydrogen phosphate.

[0018] By selecting suitable calcium salts and phosphates to provide calcium and phosphorus sources, calcium oleate precursors are obtained by reacting with oleic acid in an alkaline environment for the preparation of hydroxyapatite.

[0019] More preferably, the calcium salt is calcium chloride; and the phosphate is sodium dihydrogen phosphate.

[0020] Preferably, the mass ratio of microfibrillated cellulose, oleic acid and anhydrous ethanol is 0.05-0.2:10:10.

[0021] Oleic acid and ethanol are selected as reaction solvents, and microfibrillated cellulose is selected as a substrate. By selecting the microfibrillated cellulose in the above proportion, hydroxyapatite can be grown in situ on the surface of the microfibrillated cellulose as the reaction proceeds, thus achieving the effect of in situ growth of hydroxyapatite on the surface of the microfibrillated cellulose.

[0022] More preferably, the mass ratio of microfibrillated cellulose, oleic acid and anhydrous ethanol is 0.1:10:10.

[0023] Preferably, the molar ratio of the calcium salt, sodium hydroxide, and phosphate is 10:125:8-9.

[0024] Calcium salts and phosphates within the above range promote the in-situ growth of hydroxyapatite on the surface of microfibrillated cellulose, facilitating subsequent self-assembly to achieve three-dimensional fiber assembly and form a cellulose framework.

[0025] More preferably, the molar ratio of calcium salt, sodium hydroxide and phosphate is 10:125:9.

[0026] Preferably, the temperature of the solvothermal reaction is 160℃~190℃, and the time is 2~12h.

[0027] Solvent-thermal reaction temperatures within the above range can promote the formation of hydroxyapatite, resulting in hydroxyapatite-modified microfibrillated cellulose.

[0028] Appropriately extending the solvothermal reaction time can further form rod-shaped hydroxyapatite, which can be used to modify microfibrillated cellulose.

[0029] More preferably, the solvothermal reaction temperature is 180℃~190℃ and the time is 6h~12h, to prepare rod-shaped hydroxyapatite-modified microfibrillated cellulose.

[0030] The centrifugal filtration process involves washing with anhydrous ethanol and deionized water to remove unreacted raw materials and byproducts. After filtration, the cellulose is dispersed and stored in water to obtain hydroxyapatite-modified microfibrillated cellulose.

[0031] Preferably, the conductive material is a single-walled carbon nanotube, a multi-walled carbon nanotube, a single-layer graphene, or a multi-layer graphene.

[0032] Hydroxyapatite-modified microfibrillated cellulose was composited with conductive materials to form a membrane. The self-assembly of microfibrillated cellulose and conductive materials resulted in a surface resistivity of microfibrillated cellulose of less than 10¹¹ Ω, giving the microporous membrane based on the modified microfibrillated cellulose framework strong antistatic properties.

[0033] More preferably, the conductive material is a single-walled carbon nanotube.

[0034] Preferably, the mass ratio of the hydroxyapatite-modified microfibrillated cellulose to the conductive material is 100 to 1000:1.

[0035] Furthermore, the mass ratio of the hydroxyapatite-modified microfibrillated cellulose to the conductive material is 500:1.

[0036] Preferably, the polydimethylsiloxane comprises a polydimethylsiloxane alkylating agent and a curing agent, wherein the mass ratio of ethyl acetate to the polydimethylsiloxane alkylating agent is 50 to 150:1.

[0037] The main component of polydimethylsiloxane is polydimethylsiloxane polymer, which has good hydrophobicity and high shear resistance. When used in combination with a curing agent, it can quickly achieve the curing effect, improve the hydrophobicity of modified microfibrillated cellulose, and prepare a microporous membrane with superhydrophobicity for oil-water separation.

[0038] Furthermore, the mass ratio of ethyl acetate to polydimethylsiloxane is 100:1.

[0039] The present invention also provides a superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework prepared by the aforementioned preparation method.

[0040] The present invention also provides the application of the superhydrophobic and antistatic microporous membrane based on the modified microfibrillated cellulose framework prepared by the above preparation method in oil-water separation.

[0041] The beneficial effects of this invention are as follows:

[0042] The preparation method employed in this invention modifies microfibrillated cellulose to obtain hydroxyapatite-modified microfibrillated cellulose, which further self-assembles with conductive materials to form an interwoven cellulose framework, greatly improving the oil-water separation flux. The self-assembly with conductive materials also endows the microporous membrane with antistatic properties, resulting in a surface resistivity of less than 10 Ω·cm. 11 The microporous membrane prepared by combining Ω with polydimethylsiloxane has superhydrophobicity and a surface water contact angle of over 150°. The superhydrophobic antistatic microporous membrane prepared by this method has excellent oil-water separation flux and efficiency, as well as high stability, which promotes the widespread application of oil-water separation technology. Attached Figure Description

[0043] Figure 1 Transmission electron microscopy (TEM) images of microfibrillated cellulose (MFC) and rod-shaped hydroxyapatite-modified microfibrillated cellulose (MFC-HAP) prepared in Example 1;

[0044] Figure 2 Scanning electron microscope (SEM) images of the antistatic microporous membranes based on the modified microfibrillated cellulose framework prepared in Examples 1 to 4 and Comparative Example 1;

[0045] Figure 3 The surface water contact angle (WCA) of the antistatic microporous membranes based on the modified microfibrillated cellulose framework prepared in Examples 1 to 4, 8, 9 and Comparative Example 1;

[0046] Figure 4 The separation effect of the antistatic microporous membrane prepared in Example 1 on different types of water-in-oil emulsions stabilized by surfactants is shown in the figure.

[0047] Figure 5The separation performance of the antistatic microporous membrane prepared in Example 1 for separating water-in-oil emulsions is shown in the cycle performance diagram.

[0048] Figure 6 The diagram shows the separation effect of antistatic microporous membranes based on modified microfibrillated cellulose frameworks prepared in Examples 1 to 7 and Comparative Example 1 for separating water-in-oil emulsions. Detailed Implementation

[0049] The specific implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described in detail below are those that can be implemented or understood by those skilled in the art by referring to the prior art. The polydimethylsiloxane involved in the present invention is a commercially available product that can be purchased from the manufacturer (manufacturer: Dow Corning, product model: Dow Corning DC184). The purchased polydimethylsiloxane includes a polydimethylsiloxane alkylating agent and a curing agent, which must be used together.

[0050] Example 1

[0051] A method for preparing a superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework includes the following steps:

[0052] (1) Under mechanical stirring, 0.10 g dry weight of microfibrillated cellulose, 15 ml of 0.1 mM calcium chloride aqueous solution, 15 ml of 1.25 mM sodium hydroxide aqueous solution, and 7.5 ml of 0.18 mM sodium dihydrogen phosphate aqueous solution were added to a mixture of 9 g oleic acid and 9 g anhydrous ethanol, and stirred until homogeneous to prepare a calcium oleate precursor solution. The obtained calcium oleate precursor solution was transferred to the polytetrafluoroethylene liner of the reactor, and then heated at 180 °C for 10 h in a hydrothermal reactor. After the reaction was completed, the mixture was cooled to room temperature, and centrifuged and washed three times each with anhydrous ethanol and deionized water to obtain rod-shaped hydroxyapatite-modified microfibrillated cellulose, which was then dispersed and stored in water. Figure 1 and Figure 2 As shown, it is named MFC-HAP-10h.

[0053] (2) Take 0.2g of dry weight of rod-shaped hydroxyapatite-modified microfibrillated cellulose obtained in step (1) and 0.4mg of single-walled carbon nanotubes and mix them evenly in anhydrous ethanol by ultrasonication for 2h. After filtration, dry the mixture at 60℃ for 0.5h using a vacuum paper forming machine and demold it from the filter paper to prepare an antistatic microporous membrane based on the modified microfibrillated cellulose framework.

[0054] (3) The antistatic microporous membrane based on the modified microfibrillated cellulose framework obtained in step (2) was immersed in polydimethylsiloxane diluted with ethyl acetate for 0.5 h. The polydimethylsiloxane included a polydimethylsiloxane alkylating agent and a curing agent, wherein the polydimethylsiloxane alkylating agent was 5 g, the curing agent was 0.5 g, and the ethyl acetate was 50 g. After removal, it was dried in a vacuum drying oven at 65 °C for 2 h to cure, thereby obtaining a superhydrophobic antistatic microporous membrane based on the modified microfibrillated cellulose framework.

[0055] like Figure 3 As shown, the obtained superhydrophobic antistatic microporous membrane has a surface water contact angle of 150.9° and a surface resistivity of 3.4 × 10⁻⁶. 10 Ω. For example... Figure 4 As shown, under a pressure of 0.5 MPa, the membrane flux for separating oil-water emulsions was 3583 L·m⁻¹ for water-in-hexane, water-in-petroleum ether, water-in-1,2-dichloroethane, and water-in-soybean oil, respectively. -2 .h -1 ·bar -1 2223 L·m - 2 .h -1 ·bar -1 2460 L·m -2 .h -1 ·bar -1 and 829 L·m -2 .h -1 ·bar -1 The separation efficiencies were 99.3%, 99%, 98.8%, and 98.2%, respectively. Figure 5 As shown, the separation flux was 2639 L·m after 20 cycles. -2 .h -1 ·bar -1 The separation efficiency was 98.1%. The results show that the obtained superhydrophobic antistatic microporous membrane has good oil-water separation and circulation performance. (Example 2)

[0056] The steps of Example 2 are the same as those of Example 1, except that in step (1), the water is heated at 180°C in the hydrothermal reactor for 4 hours and named MFC-HAP-4h, and finally a superhydrophobic antistatic microporous membrane based on the modified microfibrillated cellulose framework is obtained.

[0057] The obtained superhydrophobic antistatic microporous membrane had a surface water contact angle of 116.14° and a hexane-in-water emulsion flux of 1031 L·m⁻¹. -2 ·h -1 ·bar -1 The separation efficiency is 3.5%.

[0058] The results showed that, compared with Example 1, during the preparation of rod-shaped hydroxyapatite-modified microfibrillated cellulose, only a small amount of hydroxyapatite particles adhered to the surface of the microfibrillated cellulose, and the fiber framework remained relatively flat and compact. Figure 6 As shown, poor hydrophobicity is not conducive to oil-water separation.

[0059] Example 3

[0060] The steps of Example 3 are the same as those of Example 1, except that in step (1), the water is heated at 180°C in the hydrothermal reactor for 6 hours and named MFC-HAP-6h, and finally a superhydrophobic antistatic microporous membrane based on the modified microfibrillated cellulose framework is obtained.

[0061] The obtained superhydrophobic antistatic microporous membrane had a surface water contact angle of 124.9° and a hexane-in-water emulsion flux of 1243 L·m⁻¹. -2 ·h -1 ·bar -1 The separation efficiency was 6.4%.

[0062] The results showed that, compared with Example 1, during the preparation of rod-shaped hydroxyapatite-modified microfibrillated cellulose, rod-shaped hydroxyapatite appeared and adhered to the surface of the microfibrillated cellulose, and the fiber framework remained relatively flat. Figure 6 As shown, this is not conducive to oil-water separation.

[0063] Example 4

[0064] The steps of Example 4 are the same as those of Example 1, except that in step (1), the water is heated at 180°C in the hydrothermal reactor for 8 hours and named MFC-HAP-8h, and finally a superhydrophobic antistatic microporous membrane based on the modified microfibrillated cellulose framework is obtained.

[0065] The obtained superhydrophobic antistatic microporous membrane had a surface water contact angle of 136.1° and a hexane-in-water emulsion flux of 3706 L·m⁻¹. -2 .h -1 ·bar -1 The separation efficiency was 10.2%.

[0066] The results showed that, compared with Example 1, during the preparation of rod-shaped hydroxyapatite-modified microfibrillated cellulose, a large amount of rod-shaped hydroxyapatite adhered to the surface of the microfibrillated cellulose, and the fibers were arranged radially to achieve a micro / nano structure, such as... Figure 6 As shown, the separation flux is high, but the hydrophobicity is insufficient, resulting in low separation efficiency.

[0067] Example 5

[0068] The steps of Example 5 are the same as those of Example 1, except that in step (2), it is ultrasonically mixed with 0.2 mg of single-walled carbon nanotubes to finally obtain a superhydrophobic antistatic microporous membrane based on a modified microfibrillated cellulose framework.

[0069] The oil-in-water emulsion flux of the obtained superhydrophobic antistatic microporous membrane was 3016 L·m⁻¹. -2 ·h -1 ·bar -1 The separation efficiency was 98.9%, and the surface resistivity was 7.5 × 10⁻⁶. 10 Ω.

[0070] The results showed that, compared with Example 1, the content of single-walled carbon nanotubes was reduced, the surface resistivity of the microporous membrane increased, and the antistatic properties were weakened.

[0071] Example 6

[0072] The steps of Example 6 are the same as those of Example 1, except that in step (2), it is ultrasonically mixed with 0.8 mg of single-walled carbon nanotubes to finally obtain a superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework.

[0073] The oil-in-water emulsion flux of the obtained superhydrophobic and antistatic microporous membrane was 3823 L·m. -2 ·h -1 ·bar -1 The separation efficiency was 99.3%, and the surface resistivity was 1.3 × 10⁻⁶. 10 Ω.

[0074] The results showed that, compared with Example 1, the increased content of single-walled carbon nanotubes reduced the surface resistivity of the microporous membrane and further improved the antistatic properties.

[0075] Example 7

[0076] The steps of Example 7 are the same as those of Example 1, except that in step (2), it is ultrasonically mixed with 0.4 mg of multi-walled carbon nanotubes to finally obtain a superhydrophobic antistatic microporous membrane based on a modified microfibrillated cellulose framework.

[0077] The oil-in-water emulsion flux of the obtained superhydrophobic antistatic microporous membrane was 3301 L·m. -2 ·h -1 ·bar -1 The separation efficiency was 98.3%, and the surface resistivity was 2.1 × 10⁻⁶. 12 Ω.

[0078] The results show that, compared with Example 1, the conductivity of multi-walled carbon nanotubes of the same mass is much lower than that of single-walled carbon nanotubes, which increases the surface resistivity of the microporous membrane and results in insufficient antistatic properties, which is not conducive to oil-water separation.

[0079] Example 8

[0080] The steps of Example 8 are the same as those of Example 1, except that in step (3), 5g of polydimethylsiloxane alkylating agent, 0.5g of curing agent and 25g of ethyl acetate are used to finally obtain a superhydrophobic antistatic microporous membrane based on a modified microfibrillated cellulose framework.

[0081] The surface water contact angle of the obtained superhydrophobic antistatic microporous membrane is 135.2°.

[0082] The results showed that, compared with Example 1, the increased concentration of polydimethylsiloxane resulted in a thicker coating on the microporous membrane surface, completely covering the micro / nano structure, thus making the surface hydrophobicity only related to polydimethylsiloxane.

[0083] Example 9

[0084] The steps of Example 9 are the same as those of Example 1, except that in step (3), 5g of polydimethylsiloxane alkylating agent, 0.5g of curing agent and 75g of ethyl acetate are used to finally obtain a superhydrophobic antistatic microporous membrane based on a modified microfibrillated cellulose framework.

[0085] The surface water contact angle of the obtained superhydrophobic antistatic microporous membrane is 142.7°.

[0086] The results showed that, compared with Example 1, the concentration of polydimethylsiloxane was reduced, the microporous membrane surface was coated too thinly, and the presence of large pores reduced the surface hydrophobicity.

[0087] Comparative Example 1

[0088] (1) Take 0.2g dry weight of microfibrillated cellulose and 0.4mg single-walled carbon nanotubes and mix them evenly in anhydrous ethanol by ultrasonication for 2h. After filtration, dry them at 60℃ for 0.5h using a vacuum paper forming machine. Demold them from the filter paper to prepare microfibrillated cellulose composite membrane.

[0089] (2) The microfibrillated cellulose composite membrane obtained in step (1) is immersed in polydimethylsiloxane diluted with ethyl acetate for 0.5 h. The polydimethylsiloxane includes polydimethylsiloxane alkylating agent and curing agent, with 5 g of polydimethylsiloxane alkylating agent, 0.5 g of curing agent and 50 g of ethyl acetate. After removal, it is dried in a vacuum drying oven at 65 °C for 2 h for curing.

[0090] The results showed that, compared with Example 1, the microporous membrane prepared from unmodified microfibrillated cellulose had a smoother surface and the fibers were tightly linked together, failing to achieve good hydrophobic properties. Figure 6 As shown, it is difficult to achieve oil-water separation.

Claims

1. A method for preparing a superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework, comprising the following steps: (1) Microfibrillated cellulose, calcium salt, sodium hydroxide and phosphate were added to a mixed solution of oleic acid and anhydrous ethanol and subjected to a solvothermal reaction. The microfibrillated cellulose modified with hydroxyapatite was obtained by centrifugation and filtration. (2) The hydroxyapatite-modified microfibrillated cellulose prepared in step (1) is ultrasonically mixed with a conductive substance in anhydrous ethanol, and then filtered and dried to obtain an antistatic microporous membrane based on the modified microfibrillated cellulose framework. (3) The antistatic microporous membrane based on the modified microfibrillated cellulose framework obtained in step (2) is immersed in polydimethylsiloxane diluted with ethyl acetate. The immersed antistatic microporous membrane is then dried to obtain a superhydrophobic antistatic microporous membrane based on the modified microfibrillated cellulose framework.

2. The method for preparing the superhydrophobic antistatic microporous membrane according to claim 1, characterized in that, The calcium salt mentioned is one or more of calcium nitrate, calcium hydroxide, calcium hydrogen phosphate, calcium oxide, and calcium chloride; The phosphate is one or more of sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium phosphate, phosphoric acid, and diammonium hydrogen phosphate.

3. The method for preparing the superhydrophobic antistatic microporous membrane according to claim 1, characterized in that, The mass ratio of microfibrillated cellulose, oleic acid, and anhydrous ethanol is 0.05–0.2:10:10; The molar ratio of the calcium salt, sodium hydroxide, and phosphate is 10:125:8-9.

4. The method for preparing the superhydrophobic antistatic microporous membrane according to claim 1, characterized in that, The solvothermal reaction is carried out at a temperature of 160℃ to 190℃ for a time of 2 to 12 hours.

5. The method for preparing the superhydrophobic antistatic microporous membrane according to claim 4, characterized in that, The solvothermal reaction temperature is 180℃~190℃ and the time is 6h~12h, to prepare rod-shaped hydroxyapatite-modified microfibrillated cellulose.

6. The method for preparing the superhydrophobic antistatic microporous membrane according to claim 1, characterized in that, The conductive material is a single-walled carbon nanotube, a multi-walled carbon nanotube, a single-layer graphene, or a multi-layer graphene.

7. The method for preparing the superhydrophobic antistatic microporous membrane according to claim 1, characterized in that, The mass ratio of the hydroxyapatite-modified microfibrillated cellulose to the conductive material is 100 to 1000:

1.

8. The method for preparing the superhydrophobic antistatic microporous membrane according to claim 1, characterized in that, The polydimethylsiloxane comprises a polydimethylsiloxane alkylating agent and a curing agent; The mass ratio of ethyl acetate to polydimethylsiloxane is 50–150:

1.

9. A superhydrophobic and antistatic microporous membrane based on a modified microfibrillated cellulose framework prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the superhydrophobic and antistatic microporous membrane based on the modified microfibrillated cellulose framework prepared by the preparation method of claim 9 in oil-water separation.

Images