A low-cost, high-separation-efficiency loofah-based emulsion separation membrane and its preparation method and application

Abstract

The present invention discloses a low-cost, high-separation-efficiency loofah-based emulsion separation membrane, its preparation method, and application, belonging to the technical field of oil-water separation membrane preparation. The loofah-based emulsion separation membrane comprises raw materials including loofah, sodium alginate, a graphene oxide dispersion, and a cross-linking agent. The specific preparation process comprises: uniformly mixing the loofah, sodium alginate, and graphene oxide, then adding a cross-linking agent to carry out a cross-linking reaction to obtain the loofah-based emulsion separation membrane. The separation membrane prepared by the present invention has excellent structural stability and high separation efficiency. The raw material loofah not only realizes the resource utilization of waste and saves costs, but also has the characteristics of being renewable and degradable.

Description

Technical Field

[0001] The invention belongs to the technical field of oil-water separation membrane preparation, and in particular relates to a loofah-based emulsion separation membrane with low cost and high separation efficiency, and a preparation method and application thereof. Background Art

[0002] Accidental oil spills during petroleum extraction and transportation, as well as the frequent discharge of oily wastewater, pose a serious threat to human health and economic development. Oily wastewater primarily consists of free oil, dispersed oil, and emulsified oil. Emulsified oil, due to its smaller droplet size and greater thermodynamic and kinetic stability, is more difficult to separate. Membrane separation technology is considered an effective method for emulsion separation due to its high energy efficiency, low pollution, and high efficiency. However, membrane fouling, caused by the clogging of membrane pores by oil droplets, can severely reduce membrane flux and retention.

[0003] In recent years, superhydrophilic and underwater superoleophobic membranes with water-removing properties have been designed for treating oil-in-water emulsions. These membranes achieve selective oil-water separation through specialized micro- and nanostructures and appropriate surface energies, effectively addressing membrane fouling. Although a variety of materials have been used to fabricate these membranes, most are either environmentally unsuitable or derived from increasingly depleted petroleum-based feedstocks, limiting their sustainable development.

[0004] Therefore, there is an urgent need to provide a new low-cost, high-separation-efficiency oil-water emulsion separation membrane and a preparation method thereof. Summary of the Invention

[0005] To address the above-mentioned technical problems, the present invention proposes a low-cost, high-separation-efficiency loofah-based emulsion separation membrane, its preparation method, and its application. Specifically, the present invention crushes and reshapes discarded loofahs, uses a mechanically strong sodium alginate hydrogel as a binder, and nanoparticle graphene oxide with oxygen-containing functional groups on its surface as a modifier to prepare a novel emulsified oil wastewater treatment membrane. This membrane inherits the properties of loofahs and, through the adjustment of pore size and surface properties, is particularly suitable for emulsified oil separation. It also exhibits excellent stability and reusability, and has great potential for application in the field of oil-water separation.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A low-cost, high-separation-efficiency loofah-based emulsion separation membrane (sponge-like filter material), the raw materials of which include:

[0009] Loofah sponge, sodium alginate, graphene oxide dispersion and cross-linking agent.

[0010] Beneficial effects: The present invention discloses an innovative, environmentally friendly membrane for treating emulsified oil wastewater, which is based on the unique network structure of natural loofah and its inherent hydrophilic and oleophobic properties. In order to reduce the pore size of the original loofah network to adapt to the size of oil droplets in the emulsified oil wastewater, the discarded loofah is crushed and used as the supporting skeleton of the membrane, and the loofah fibers are further wrapped with sodium alginate hydrogel, and the large-pore loofah is further reshaped, cleverly adjusting the pore size of the loofah from the millimeter level to the micron level to meet the needs of emulsified oil wastewater treatment. In addition, the present invention also incorporates nanoparticle graphene oxide with oxygen-rich functional groups on the surface as a modifier. These nanoparticles can not only improve the strength of the hydrogel, but also promote the formation of specific micro-nanostructures on the membrane surface, significantly improving the mechanical strength and hydrophilicity / underwater oleophobicity of the membrane. This invention leverages the synergistic effect of sodium alginate and graphene oxide to enhance the interaction between the loofah, sodium alginate, and graphene oxide. This not only allows the crushed loofah to bind tightly, but also significantly improves the structural stability of the separation membrane. The resulting separation membrane is not only highly stable but also reusable, making it ideal for long-term emulsion separation processes.

[0011] Optionally, the pore size of the loofah-based emulsion separation membrane is 5-20 μm.

[0012] Optionally, the preparation steps of the loofah are:

[0013] The discarded loofah was fully crushed with a grinder and sieved to remove the powdered material (these powders cannot be entangled with each other to serve as a skeleton, so they must be sieved to remove). The crushed loofah (short filaments less than 1 cm) was placed in ethanol and deionized water, stirred and washed, and then placed in a 40°C oven to dry to constant weight.

[0014] Optionally, the mass ratio of the loofah, sodium alginate and graphene oxide dispersion is: 1:(1-1.25):50.

[0015] Beneficial effect: Within the dosage ratio range of the above three raw materials defined in the present invention, a stable membrane material suitable for long-term emulsion separation can be prepared. If the amount of loofah is too low, its entanglement is insufficient, resulting in a too loose membrane skeleton; if the content is too high, the loofah will overflow the mold, and the gel will not be able to completely cover the loofah; if the sodium alginate concentration (dosage) is too low, the gel strength will be insufficient, making it difficult to firmly adhere to the crushed loofah; if the concentration (dosage) is too high, the gel viscosity will increase and the fluidity will deteriorate, which will not only affect the film-making efficiency, but also fail to ensure that the gel completely wraps all the loofahs; if the graphene oxide concentration (dosage) is too low, the strength of the gel and the degree of bonding between it and the loofah will be weakened; if the concentration (dosage) is too high, only a small amount of sodium alginate can be dissolved in the graphene oxide dispersion, thereby affecting the subsequent calcium chloride cross-linking process. Therefore, the concentrations of these three need to be controlled within the range defined in the present invention.

[0016] Furthermore, the mass ratio of the loofah sponge, sodium alginate and graphene oxide dispersion is 1:1:50.

[0017] Optionally, the sodium alginate Mw is 2.0×10 5 g / mol, M / G=0.8; wherein M / G refers to the ratio of β-D-mannuronic acid (M) to α-L-guluronic acid (G).

[0018] Beneficial effects: Sodium alginate with the above-mentioned weight-average molecular weight and M / G ratio defined by the present invention can form a gel having both hardness and flexibility, and can be used as an adhesive for a separation membrane.

[0019] Optionally, the concentration of the graphene oxide dispersion is 1-5 mg / mL.

[0020] Optionally, the cross-linking agent is a CaCl2 solution with a mass fraction of 1-5%.

[0021] The second technical solution of the present invention:

[0022] A method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency comprises the following steps:

[0023] The loofah, sodium alginate and graphene oxide dispersion are uniformly mixed, and then a cross-linking agent is added to carry out a cross-linking reaction to obtain the loofah-based emulsion separation membrane.

[0024] Optionally, the method for preparing the loofah-based emulsion separation membrane comprises the following steps:

[0025] adding sodium alginate to the graphene oxide dispersion and stirring uniformly to obtain a mixed solution;

[0026] Laying the loofah flat and filling it into the mold with holes on the cover; then adding the mixed liquid into the mold so that the loofah is completely immersed;

[0027] The mold is covered with a cover surface and immersed in a cross-linking agent to perform a cross-linking reaction to obtain the loofah-based emulsion separation membrane.

[0028] Optionally, the stirring time is 1-5 hours.

[0029] Optionally, the cross-linking reaction time is 8 hours.

[0030] Optionally, the mold is cylindrical with a height of 10 mm and a diameter of 40 mm; it includes two upper and lower covers, each cover has 6 holes in two rows, and the diameter of each hole is ∼3 mm.

[0031] Beneficial effect: The pore size of the cover is used to facilitate the rapid penetration of the calcium chloride solution into the material when it is immersed in the calcium chloride solution for cross-linking.

[0032] The third technical solution of the present invention:

[0033] Application of the loofah-based emulsion separation membrane in separating emulsified oil.

[0034] Optionally, the surfactant in the emulsified oil is Tween 80, SDS or CTAB.

[0035] Compared with the prior art, the present invention has the following advantages and technical effects:

[0036] 1. Environmentally friendly: Traditional metal mesh and polyvinylidene fluoride (PVDF) membrane materials both have drawbacks: metal wire is difficult to degrade, while PVDF is derived from increasingly scarce petroleum resources, both of which are environmentally unfriendly. In contrast, the membrane used in this invention is primarily made from discarded loofah sponges, which not only recycles waste but also makes the loofah itself renewable and biodegradable.

[0037] 2. Simple preparation: The preparation of the oil-water emulsion separation membrane of the present invention only requires crushing the original loofah sponge, and then using sodium alginate, which has a polysaccharide structure similar to cellulose, the main component of loofah sponge, as an adhesive to reshape the structure. At the same time, graphene oxide is introduced as a modifier. This preparation method is simple and efficient and is suitable for industrial production.

[0038] 3. Excellent performance: The main structure and added materials of the oil-water emulsion separation membrane prepared by the present invention are hydrophilic. The sodium alginate coating enables the crushed loofah to be tightly combined. The introduction of nanoparticle graphene oxide not only enhances the mechanical properties of the membrane, but also significantly improves the underwater oil contact angle. That is, the oil-water emulsion separation membrane prepared by the present invention exhibits excellent structural stability and efficient separation ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0040] Figure 1 This is a schematic diagram of the homemade mold structure used in the present invention;

[0041] Figure 2 (a) is a microscopic image of the original untreated loofah, (b) is a microscopic image of the pure sodium alginate remodeled pulverized loofah separation membrane prepared in Comparative Example 1, and (c)-(f) are microscopic images of the sodium alginate / graphene oxide remodeled loofah-based emulsion separation membranes prepared in Examples 1-4, respectively;

[0042] Figure 3 (a) is a scanning electron micrograph of a crushed and dried loofah (short filaments less than 1 cm), (b) is a scanning electron micrograph of a crushed loofah separation membrane remodeled with pure sodium alginate prepared in Comparative Example 1, and (c)-(f) are scanning electron micrographs of sodium alginate / graphene oxide remodeled loofah-based emulsion separation membranes prepared in Examples 1-4, respectively;

[0043] Figure 4 (a)-(c) are respectively microscopic images of hexane / water emulsions dispersed with different emulsions (Tween-80, SDS, CTAB) filtered through the sodium alginate / graphene oxide remodeled loofah-based emulsion separation membrane prepared in Example 1 of the present invention before filtration; Figures (d)-(f) are respectively photographs of hexane / water emulsions dispersed with different emulsions (Tween-80, SDS, CTAB); Figures (g)-(i) are respectively microscopic images of hexane / water emulsions dispersed with different emulsions (Tween-80, SDS, CTAB) filtered through the sodium alginate / graphene oxide remodeled loofah-based emulsion separation membrane prepared in Example 1 of the present invention after filtration;

[0044] Figure 5 Figure 2 shows the bending resistance of the separation membrane after immersion in water for 20 days. (a) shows the pure sodium alginate remodeled loofah separation membrane prepared in Comparative Example 1. (b) shows the sodium alginate / graphene oxide remodeled loofah-based emulsion separation membrane prepared in Example 1 of the present invention.

[0045] Figure 6 These are repeatability test graphs of the pure sodium alginate-reshaped crushed loofah separation membrane prepared in Comparative Example 1 and the sodium alginate / graphene oxide-reshaped loofah-based emulsion separation membrane prepared in Example 1, where (a) is the separation efficiency, (b) is the flux, (c) is the underwater oil contact angle, and (d) is the stress. DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0047] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0048] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0049] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0050] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0051] The present invention discloses a method for preparing an emulsion separation membrane, which specifically includes the following steps:

[0052] (1) The discarded loofah was fully crushed with a grinder, and the powdery substances were sieved to remove the powdered substances. The crushed loofah was placed in ethanol and deionized water for stirring and cleaning, and then placed in a 40°C oven for drying; the loofah powder was evenly spread on a homemade cylindrical mold; Figure 1 As shown, the homemade cylindrical mold is made of stainless steel, has a height of 10 mm and a bottom diameter of 40 mm; it includes two upper and lower covers, each cover has 6 holes in two rows, and the hole diameter is ~3 mm.

[0053] (2) dissolving sodium alginate (SA) in a graphene oxide dispersion and stirring for 1-5 h to obtain a sodium alginate / graphene oxide mixture; after removing bubbles, slowly pouring the mixture into the above-mentioned homemade cylindrical mold so that the sodium alginate / graphene oxide mixture fully wraps the loofah;

[0054] (3) After the mold is covered, the entire mold is placed in a CaCl2 solution for cross-linking and solidification; finally, the re-formed loofah membrane in the mold is taken out, soaked in water, and stored for future use; this membrane is called SA / GO-loofah fiber (SO-LF).

[0055] In some optional embodiments, the concentration of the graphene oxide dispersion in step (2) is 1-5 mg / mL.

[0056] In some optional embodiments, the mass fraction of CaCl2 in step (3) is 1-5%.

[0057] The embodiment of the present invention also discloses an emulsion separation membrane prepared by the above preparation method.

[0058] The raw materials used in the present invention are all purchased from the market. In the following examples, sodium alginate Mw = 2.0 × 10 5 g / mol, M / G = 0.8; where M / G refers to the ratio of β-D-mannuronic acid (M) to α-L-guluronic acid (G); the graphene oxide concentration was 5 mg / mL and was purchased from Shenzhen Suiheng Graphene Technology Co., Ltd.

[0059] The technical solution of the present invention is further illustrated by the following examples.

[0060] Example 1

[0061] A method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency, wherein the separation membrane is prepared by cross-linking loofah, sodium alginate and graphene oxide with calcium chloride, and specifically comprises the following steps:

[0062] (1) Preparation of membrane matrix material: Discarded loofah was fully crushed with a grinder, sieved to remove powdery substances, and the obtained crushed loofah was placed in ethanol and deionized water for stirring and cleaning, and then placed in a 40°C oven for drying; 1.0g of crushed loofah was weighed and spread flat on a mold;

[0063] (2) Preparation of sodium alginate / graphene oxide mixed solution: The purchased 5 mg / mL graphene oxide dispersion was prepared into 2 mg / mL, 1 g of sodium alginate was weighed and added to 50 g of graphene oxide dispersion, stirred for 4 h to completely dissolve the sodium alginate, and then allowed to stand for 8 h to remove bubbles to obtain a mixed solution;

[0064] (3) Preparation of a loofah-based separation membrane: slowly pour the mixed solution in step (2) into the mold in step (1) so that the mixed solution completely wraps the loofah fibers; cover the mold with a matching perforated cover, and place the entire mold in a 2.5% by mass CaCl2 solution for crosslinking for 8 hours; finally, store the reshaped loofah-based separation membrane in deionized water for later use.

[0065] Example 2

[0066] A method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency is different from that of Example 1 in that:

[0067] The amount of sodium alginate added in step (2) is 1.25 g.

[0068] Other steps and conditions are consistent with those in Example 1.

[0069] Example 3

[0070] A method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency is different from that of Example 1 in that:

[0071] The concentration of the graphene oxide dispersion in step (2) is prepared to be 3 mg / mL.

[0072] Other steps and conditions are consistent with those in Example 1.

[0073] Example 4

[0074] A method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency is different from that of Example 1 in that:

[0075] The mass concentration of the calcium chloride solution in step (3) is 5%.

[0076] Other steps and conditions are consistent with those in Example 1.

[0077] Comparative Example 1

[0078] A method for preparing an emulsion separation membrane, which is different from Example 1 in that:

[0079] Step (2) is: 1 g of sodium alginate is added to 50 g of distilled water, stirred for 4 h to completely dissolve the sodium alginate, and then allowed to stand for 8 h to remove bubbles to obtain a mixed solution.

[0080] Other steps and conditions are consistent with those in Example 1.

[0081] Figure 2(a) is a microscope image of the original loofah, (b) is a microscope image of the crushed loofah separation membrane reshaped by pure sodium alginate prepared in Comparative Example 1, and (c)-(f) are microscope images of the sodium alginate / graphene oxide reshaped loofah-based emulsion separation membranes prepared in Examples 1-4, respectively. It can be seen from the figures that after crushing and reshaping, the pore size of the loofah itself is greatly reduced, and the surface of the loofah is wrapped with a layer of evenly dispersed gel, which further fills the pores.

[0082] Figure 3 (a) is a scanning electron micrograph of a pulverized and dried loofah, (b) is a scanning electron micrograph of a pulverized loofah separation membrane remodeled with pure sodium alginate prepared in Comparative Example 1, and (c)-(f) are scanning electron micrographs of a loofah-based emulsion separation membrane remodeled with sodium alginate / graphene oxide prepared in Examples 1-4, respectively. As can be seen from the figures, the gel layer of the membrane wrapped with pure sodium alginate is easily damaged. However, after further introduction of graphene oxide, the gel is tightly wrapped around the loofah fibers, and even after freeze-drying, there is little or no damage. This indicates that graphite oxide promotes the bonding strength between the gels and between the gel and the loofah.

[0083] Effect verification

[0084] First, a water-to-hexane volume ratio of 9:1 was maintained, and the concentration of surfactants (Tween 80, SDS, and CTAB, respectively) was controlled at 0.2 mg / mL. The mixtures were stirred at 2500 rpm for 3 hours to prepare oil-in-water emulsions. The separation membranes prepared in Comparative Example 1 and Example 1 were sandwiched between the wide-mouth bottle and suction bottle of a filtration apparatus, and the oil-in-water emulsions were separated using a pressure-driven filtration system (suction filtration pressure of 0.25 bar).

[0085] Figure 4 Figures (a)-(c) are microscopic images of hexane / water emulsions dispersed with different emulsions (Tween-80, SDS, and CTAB) before filtration through the sodium alginate / graphene oxide-remodeled loofah-based emulsion separation membrane prepared in Example 1 of the present invention; Figures (d)-(f) are photographs of hexane / water emulsions dispersed with different emulsions (Tween-80, SDS, and CTAB); and Figures (g)-(i) are microscopic images of hexane / water emulsions dispersed with different emulsions (Tween-80, SDS, and CTAB) after filtration through the sodium alginate / graphene oxide-remodeled loofah-based emulsion separation membrane prepared in Example 1 of the present invention. As can be seen from the figures, no obvious oil droplets were observed in any of the three filtrates after filtration through the sodium alginate / graphene oxide-remodeled loofah-based emulsion separation membrane prepared in Example 1. This indicates that the separation membrane prepared in the present invention has excellent retention rate for emulsions.

[0086] Figure 5Figures 1 and 2 show the bending resistance of separation membranes after 20 days of immersion in water. (a) shows the pure sodium alginate-reshaped, crushed loofah separation membrane prepared in Comparative Example 1, and (b) shows the sodium alginate / graphene oxide-reshaped loofah-based emulsion separation membrane prepared in Example 1 of the present invention. As can be seen from the figures, after 20 days of deionized water immersion, the pure sodium alginate-coated separation membrane (Comparative Example 1) becomes extremely fragile when bent. In contrast, the improved sodium alginate / graphene oxide-coated separation membrane (Example 1) according to the present invention quickly recovers to its original shape, demonstrating excellent elasticity and durability.

[0087] Figure 6 The repeatability test diagram of the pure sodium alginate remodeled loofah separation membrane prepared in Comparative Example 1 and the sodium alginate / graphene oxide remodeled loofah-based emulsion separation membrane prepared in Example 1, wherein (a) is the separation efficiency, (b) is the flux, (c) is the underwater oil contact angle, and (d) is the stress. As can be seen from the figure, the reusability of the two membranes was compared in terms of separation efficiency, flux, underwater oil contact angle, and stress. It was found that the loofah membrane coated with sodium alginate / graphene oxide has better reusability. Specifically, the compressive strength (stress) of the separation membrane prepared in Example 1 of the present invention is as high as 17.95MPa, the underwater oil contact angle reaches 151.6°, and the retention efficiency of hexane in the hexane / water emulsion is close to 100%.

[0088] In summary, the present invention makes full use of the biomass properties of loofah, combines sodium alginate and graphene oxide, and prepares an emulsified oil wastewater treatment membrane with excellent separation performance and anti-pollution ability. Among them, loofah is selected as the supporting skeleton of the membrane because of its three-dimensional network space structure and multi-level microscopic pores, as well as the polar hydroxyl groups on its surface; by crushing the loofah and using sodium alginate as an adhesive, and graphene oxide as a modifier, a dense structure, underwater super-oleophobic membrane material is successfully prepared. The separation membrane shows good separation effect on three water-in-oil emulsions stabilized by different emulsifiers. That is, the present invention not only provides an environmentally friendly and renewable membrane material, but also provides a new solution for the treatment of emulsified oil wastewater.

[0089] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A loofah-based emulsion separation membrane with low cost and high separation efficiency, characterized in that: Ingredients include: loofah, sodium alginate, graphene oxide dispersion and cross-linking agent; The method for preparing the loofah-based emulsion separation membrane with low cost and high separation efficiency comprises the following steps: The loofah, sodium alginate and graphene oxide dispersion are uniformly mixed, and a cross-linking agent is added to carry out a cross-linking reaction to obtain the loofah-based emulsion separation membrane; The preparation steps of described loofah are: The discarded loofahs are first crushed and sieved, then placed in ethanol and deionized water for stirring and cleaning, and finally dried.

2. A loofah-based emulsion separation membrane with low cost and high separation efficiency according to claim 1, characterized in that, The mass ratio of the loofah sponge, sodium alginate and graphene oxide dispersion is 1: (1-1.25):

50.

3. A loofah-based emulsion separation membrane with low cost and high separation efficiency according to claim 2, characterized in that, The mass ratio of the loofah sponge, sodium alginate and graphene oxide dispersion is 1:1:

50.

4. A loofah-based emulsion separation membrane with low cost and high separation efficiency according to claim 1, characterized in that, The concentration of the graphene oxide dispersion is 1-5 mg / mL.

5. A loofah-based emulsion separation membrane with low cost and high separation efficiency according to claim 1, characterized in that, The cross-linking agent is a CaCl2 solution with a mass fraction of 1-5%.

6. A method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency, characterized in that: The following steps are involved: The loofah, sodium alginate and graphene oxide dispersion are uniformly mixed, and then a cross-linking agent is added for cross-linking and curing to obtain the loofah-based emulsion separation membrane according to any one of claims 1 to 5.

7. The method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency according to claim 6, wherein The following steps are involved: adding sodium alginate to the graphene oxide dispersion and stirring uniformly to obtain a mixed solution; Laying the loofah in a mold with a hole on the cover; then adding the mixed liquid into the mold so that the loofah is completely immersed; The mold is covered with a cover surface and immersed in a cross-linking agent to perform a cross-linking reaction to obtain the loofah-based emulsion separation membrane.

8. The method for preparing a loofah-based emulsion separation membrane with low cost and high separation efficiency according to claim 7, wherein The stirring time is 1-5h; and / or The cross-linking reaction time is 8 hours.

9. Use of the loofah-based emulsion separation membrane according to any one of claims 1 to 5 in separating emulsified oil.

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