Natural latex / graphene aerogel composite material for oil-water separation and preparation method thereof

Abstract

The invention relates to a natural latex / graphene aerogel composite material for oil-water separation and a preparation method thereof. The preparation method comprises the following steps: firstly, preparing graphene oxide by an improved Hummers method, and then preparing the natural latex / graphene aerogel by combining a hydrothermal self-assembly method, a bubble template method and a freeze-drying method. And then adjusting the use amount of the natural latex and process parameters to optimize the performance of the natural latex / graphene aerogel, thereby preparing the natural latex / graphene aerogel with optimal performance. The preparation method has the beneficial effects that the problem of oil-water separation performance is solved, excellent adsorption performance is shown on organic reagents (ethanol, n-butane, liquid paraffin, trichloromethane, xylene, kerosene, edible oil, cyclohexane and the like), and the adsorption range is 43.82-189.86 g / g; after 10-20 times of cycle tests, the thickness recovery rate and the absorption capacity are still 92% or above of the initial value.

Description

Technical Field

[0001] This invention relates to the technical field of water pollution prevention and treatment, and in particular to a natural latex / graphene aerogel composite material for oil-water separation and its preparation method. Background Technology

[0002] With the rapid development of modern society, oily wastewater has been recognized as one of the most concerning sources of pollution worldwide. Oily wastewater is the leading contributor to the "three wastes" (wastewater, industrial waste residue, and waste gas), composed of fats, oils, and various suspended, highly concentrated dissolved substances (organic / inorganic). Oil droplets in oily wastewater mainly exist as floating oil, dispersed oil, emulsified oil, and dissolved oil. Floating and dispersed oil can form oil films or layers on the wastewater surface and are relatively easy to remove. Dissolved oil has a lower concentration in oily wastewater but is difficult to remove using conventional methods. Once discharged, oily wastewater causes severe damage to marine life, seriously disrupts the ecological balance, and endangers human and animal health. Furthermore, subsequent crude oil recovery and waste oil treatment will generate substantial and ongoing economic losses and environmental damage.

[0003] Currently, common methods for treating oily wastewater are mainly divided into physical, chemical, biological, and physicochemical methods. Gravity sedimentation, a physical method, is not suitable for separating emulsified and dissolved oils; biological methods have poor biochemical properties; coagulation methods produce a lot of sludge and are difficult to dewater, and also have shortcomings in terms of operating costs, oil removal efficiency, and ease of operation. Adsorption methods use adsorbent materials to adsorb dissolved oil from the wastewater onto the surface and interior of the material, converting the liquid oil into a temporarily controllable and easily collected semi-solid or solid state, thus achieving oil-water separation. Due to its advantages of high efficiency, low cost, and no secondary environmental damage, it has become the most commonly used method for treating oily wastewater. However, currently prepared adsorbent materials have disadvantages such as poor adsorption selectivity, low efficiency, and high adsorbent costs. Therefore, it is necessary to prepare adsorbent materials with high oil-water separation efficiency, good recyclability, and low cost and availability, so as to achieve the effects of reducing energy consumption, reducing pollution, being economically efficient, and contributing to the transformation of society towards green development and green lifestyles.

[0004] Aerogels, as porous materials, exhibit high adsorption capacity in oil-water separation systems. While they demonstrate excellent adsorption performance for various water pollutants (including heavy metal ions, organic liquids, and oil-based contaminants), they still suffer from poor hydrophobicity and mechanical properties. Graphene aerogel (GA) is a carbon-based aerogel derived from graphene nanomaterials and possessing a three-dimensional porous network structure. Graphene aerogels exhibit low apparent density, large specific surface area, abundant pore structure, high conductivity, good hydrophobicity, and excellent selective oil-water adsorption capacity, while maintaining nanoscale characteristics on a macroscopic scale. However, graphene aerogels also suffer from poor mechanical properties, particularly poor flexibility. Modifying the graphene aerogel framework to improve its mechanical properties, thereby enhancing its practicality in oil-water separation systems, has significant application value. Summary of the Invention

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a natural latex / graphene aerogel composite material for oil-water separation and its preparation method, which solves the technical problem of oily wastewater treatment. The graphene aerogel is modified. A polymer-modified carbon-based material strategy is adopted. Natural latex (NRL), which is amphiphilic, is added as a crosslinking component to design a natural latex / graphene aerogel composite with suitable hydrophilicity and hydrophobicity, thereby improving the oil-water separation performance and mechanical properties of the graphene aerogel.

[0006] The performance of natural latex / graphene aerogels varies depending on the amount of natural latex added and the rotation speed of the foam template. By combining the reduction self-assembly method, the foam template method, and the freeze-drying method, the process parameters were optimized to prepare natural latex / graphene aerogels with optimal oil-water separation performance.

[0007] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0008] This invention provides a method for preparing a modified natural latex / graphene aerogel composite as follows:

[0009] (1) Sodium dodecyl sulfate solution (SDS), ascorbic acid, and natural latex were mixed in a graphene oxide solution to obtain a natural latex graphene precursor.

[0010] (2) The natural latex graphene precursor was transferred to a 25mL reactor, subjected to hydrothermal reaction, frozen, and reduced to obtain natural latex-modified graphene.

[0011] (3) The graphene modified with natural latex was dispersed in 90% ethanol solution, soaked and washed, and then freeze-dried under vacuum to obtain a natural latex / graphene aerogel composite.

[0012] Alternatively, the graphene oxide solution can be prepared by the following steps:

[0013] Laboratory-purified large-flake graphite was reacted with NaNO3 at a ratio of 2-3:1 in 200-250 mL of concentrated sulfuric acid in an ice-water bath with stirring for 0.5 h. Then, 20-30 g of KMnO4 was slowly added, and the reaction was carried out at 10-15 °C for 0.5-1 h. The mixture was then poured into 1-2 L of distilled water and reacted at 80-100 °C for 15-60 min. The residual potassium permanganate and manganese dioxide were reduced to soluble manganese sulfate with 10-30% H2O2. After precipitation for 24 h, the unexfoliated graphite was removed by centrifugation, yielding a yellow-brown solution. This solution was then washed by centrifugation to remove SO4. 2- Graphene oxide was obtained.

[0014] Alternatively, graphene aerogels can be prepared by the following steps:

[0015] In step (1), no natural latex is added, and the remaining steps are the same as those for natural latex / graphene aerogel, resulting in graphene aerogel for comparison.

[0016] Optionally, the specific steps of step (1) are as follows:

[0017] SDS, ascorbic acid, and natural latex were added to a graphene oxide solution that had been sonicated for 30 minutes. The solution was then stirred at 1000-2500 rpm for 10 minutes until foaming occurred, thus obtaining a natural latex graphene composite.

[0018] Optionally, the mass ratio of graphene oxide to natural latex is 0.5-3:1, and the mass ratio of graphene oxide, SDS, and ascorbic acid is 0.5-1:0.8-1:1.5-2.

[0019] Optionally, the specific steps of step (2) are as follows:

[0020] The obtained natural latex graphene composite was transferred to a 25 mL reactor and hydrothermally reacted at 70 °C for 2 h. Then it was taken out and frozen at -18 °C for 6-8 h, and then reduced at 130 °C for 2 h to obtain natural latex modified graphene.

[0021] Optionally, the specific steps of step (3) are as follows:

[0022] Natural latex-modified graphene was dispersed in a 90% ethanol solution and washed 2-5 times. After washing and drying, it was freeze-dried under vacuum for 18-24 hours to obtain natural latex / graphene aerogel.

[0023] The beneficial effects of this invention are as follows: This invention provides a natural latex / graphene aerogel composite material for oil-water separation and its preparation method. Because graphene oxide is prepared using a modified Hummers method, and the natural latex / graphene aerogel is prepared by combining hydrothermal self-assembly, bubble template method, and cryogenic casting method, compared with existing technologies, it can promote the application of graphene aerogel in the adsorption treatment of oily wastewater. It achieves excellent compressive strength with a hydrophobic angle of 132.5° and a compression resistance of 7.01 kPa at 50% compression. It also exhibits strong selective adsorption performance for organic solvents such as ethanol, n-butane, liquid paraffin, chloroform, xylene, kerosene, edible oil, and cyclohexane, with an adsorption range of 43.82 to 189.86 g / g, demonstrating excellent adsorption performance. After 10-20 cycles, its thickness recovery rate and absorption capacity remain above 92% of the initial value.

[0024] This invention prepares graphene oxide using a modified Hummers method, resulting in graphene oxide sheets with oxygen-containing functional groups primarily consisting of epoxy and carboxyl groups. This improves the graphene oxide's solubility and stability in aqueous solutions. After reduction, the graphene oxide component forms the graphene aerogel framework, becoming an oleophilic component. The remaining oxygen-containing functional groups on the reduced graphene oxide interact with hydrogen bonds between these functional groups and protein molecules on the surface of natural latex, forming an interpenetrating network. This enhances the flexibility of the graphene aerogel, resulting in a natural latex / graphene aerogel with excellent oil-water separation properties.

[0025] Secondly, embedding natural latex into graphene oxide allows the highly functional groups of the latex to interact with the oxygen-containing groups on the graphene oxide, resulting in a strong bond between them. This increases the latex's compressive strength and gives the resulting natural latex / graphene aerogel a 3D framework with a stable structure. This helps to improve its porosity, pore size, and uniform pore arrangement, thereby increasing the effective oil absorption space and capillary force, and improving its adsorption performance.

[0026] In the preparation method, the steps of combining hydrothermal self-assembly, bubble template method and freeze-drying technology can not only retain the open-pore structure provided by the foam template method of natural latex / graphene aerogel, but also make the porous structure replicate the shape of ice crystal directional growth provided by freeze casting, and finally form an open-pore 3D skeleton structure with a pore size of about 100-500μm. Attached Figure Description

[0027] Figure 1 SEM image of natural latex / graphene aerogel at 500 μm magnification;

[0028] Figure 2 SEM images of graphene aerogel and natural latex / graphene aerogel at a magnification of 5 μm.

[0029] Figure 3 XPS images of graphene aerogel and natural latex / graphene aerogel;

[0030] Figure 4 Ramman diagrams for graphene oxide, graphene aerogel, and natural latex / graphene aerogel;

[0031] Figure 5 Photograph of the water contact angle of natural latex / graphene aerogel;

[0032] Figure 6 Figure showing the adsorption capacity of natural latex / graphene aerogel;

[0033] Figure 7 This is a diagram of a cyclic compression test of natural latex / graphene aerogel. Detailed Implementation

[0034] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] This invention presents a natural latex / graphene aerogel composite material for oil-water separation and its preparation method. Graphene oxide was prepared using a modified Hummers method. The natural latex / graphene aerogel was prepared by combining hydrothermal self-assembly, bubble template method, and cryogenic casting method. This natural latex / graphene aerogel exhibits excellent adsorption properties, compressive strength, and recyclability, making it advantageous for practical applications in oily wastewater treatment.

[0036] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0037] Detailed Implementation Description Section:

[0038] Example 1: A natural latex / graphene aerogel composite material for oil-water separation, the preparation method of which includes the following steps:

[0039] Step (1): Add 40 mg of graphene oxide solution to a beaker, sonicate for 30 min, remove and then add 0.8 mL of 50 mg / mL SDS, 2 mL of 40 mg / mL ascorbic acid and 0.1 mL of 200 mg / mL natural latex in sequence. Then stir at 1000 rpm for 10 min to foam and obtain natural latex graphene composite.

[0040] Step (2): Transfer the natural latex graphene composite to a 25 mL reactor and react at 70 °C for 2 h. Remove it and freeze it at -18 °C for 6 h, then reduce it at 130 °C for 2 h.

[0041] Step (3): The graphene modified with natural latex was dispersed in 90% ethanol and washed three times to remove unreacted reagents. The water was changed every 4 hours. Finally, the washed graphene aerogel was freeze-dried under vacuum at -80℃ for 24 hours to obtain natural latex / graphene aerogel.

[0042] Graphene oxide was prepared by a modified Hummers method;

[0043] While graphene aerogels possess adsorption properties for various water pollutants, they also exhibit drawbacks such as poor hydrophobicity and mechanical properties. The oxygen-containing functional groups on the prepared graphene oxide sheets are primarily epoxy and carboxyl groups, which can improve solubility and stability in aqueous solutions, providing conditions for latex composites and co-condensation, and also enhancing the hydrophobicity of the aerogel. However, its compression robustness remains poor, leading to a sharp decrease in absorption capacity after mechanical extrusion. Embedding latex into graphene oxide allows for a strong bond between the polar functional groups of the latex and the oxygen-containing groups on the graphene oxide, enhancing its compressive strength. Natural latex / graphene aerogels prepared through a combination of hydrothermal self-assembly, bubble template method, and freeze-drying technology not only retain the open-pore structure provided by the foam template but also replicate the directional growth shape of ice crystals provided by freeze casting, ultimately forming an open-pore 3D framework structure that promotes pore distribution. The modified aerogel retains its low density advantage, forming a high-performance natural latex / graphene aerogel composite adsorbent material. Figure 1 The prepared natural latex / graphene aerogel has protrusions on its surface. Figure 2 This is because natural latex is encapsulated between graphene oxide sheets, forming a sandwich structure of graphene oxide-natural latex-graphene oxide, constituting an interpenetrating network. The rubber particles have a diameter of 800-1200 nm, indicating that natural latex was successfully introduced into the aerogel. This is not only due to the strong hydrophobicity of reduced graphene oxide and natural latex, but also attributed to the hydrogen bonding interactions between the remaining oxygen-containing functional groups on the reduced graphene oxide and the protein molecules on the surface of the natural latex. The C1s spectrum of the graphene aerogel has four peaks: CC / CH at 284.8 eV, CO at 285.85 eV, epoxy group at 286.65 eV, and O=CO bond at 288.15 eV. Carbon atoms account for 86.39% and oxygen atoms account for 13.61%. Figure 3a) The C1s spectrum of natural latex / graphite aerogel has three peaks: CC / CH at 284.8 eV, CO at 285.9 eV, and epoxy group at 286.95 eV. Carbon atoms account for 90.66% and oxygen atoms for 9.34%, which is 4.27% higher than that of graphene aerogel. Figure 3 b) indicates successful NRL doping. After the addition of NRL, I D / I G The NRL decreased from 1.18 to 1.09, indicating a gradual shift towards order in the sheets, demonstrating that NRL was successfully anchored on the graphene oxide sheets. Figure 4 The wettability of the natural latex / graphene aerogel was further characterized by the static water contact angle, which was 132.5°. Figure 5 This indicates that natural latex / graphene aerogels possess both strong hydrophobicity and strong oleophilicity. Furthermore, adsorption performance tests were conducted using different organic reagents (ethanol, n-butane, liquid paraffin, chloroform, xylene, kerosene, edible oil, and cyclohexane), with adsorption capacities of 147.91 g / g, 98.84 g / g, 86.84 g / g, 189.87 g / g, 138.66 g / g, 43.81 g / g, 51.79 g / g, and 89.99 g / g, respectively. Figure 6 b). This high absorption capacity is mainly attributed to the well-developed, uniformly arranged pores in the aerogel, which provide ample space for storing absorbed liquids. The oil absorption mechanism of the aerogel depends primarily on its macroscopic and microscopic morphology and the properties of the solvent (including viscosity, molecular size, polarity, and density). Differences in the absorption capacity of various organic reagents may be due to the inherent affinity between the aerogel and different liquids. Subsequently, 20 cyclic compression tests were conducted on the latex / graphene aerogel in the vertical direction. During this process, the strain was absorbed by the deformation of the numerous pores in the aerogel. When the applied load was released, these compressed pores could recover their original shape, and the thickness could be restored to 94.2% of its original value. Figure 7 b). Therefore, the aerogel can withstand repeated compressive strain without structural collapse. This high elasticity indicates that the absorbed oil can be easily extruded from the natural latex / graphene aerogel through mechanical extrusion, thus ensuring its application prospects in petroleum recovery and aerogel recycling. The absorption / extrusion cycle was then repeated 10 times to evaluate the recyclability of the natural latex / graphene aerogel. When the adsorbed saturated aerogel was extruded, the absorbed solvent was carried from the internal pores of the aerogel to the surface. After release by applying external force, the residual solvent on the surface was quickly reabsorbed due to the oleophilic nature of the natural latex / graphene aerogel. The natural latex / graphene aerogel exhibits excellent compressive strength and recyclability, retaining more than 92% of its initial absorption capacity after 10 adsorption-extrusion cycles. Figure 6a).

[0044] Example 2: A natural latex / graphene aerogel composite material for oil-water separation, the preparation method of which includes the following steps:

[0045] Step (1): Add 40 mg of graphene oxide solution to a beaker, sonicate for 30 min, remove and then add 0.8 mL of 50 mg / mL sodium dodecyl sulfate (SDS), 2 mL of 40 mg / mL ascorbic acid and 0.2 mL of 200 mg / mL natural latex in sequence. Then stir at 2000 rpm for 10 min to foam and obtain natural latex graphene composite.

[0046] Step (2): Transfer the natural latex graphene composite to a 25 mL reactor and react at 70 °C for 2 h. Remove it and freeze it at -18 °C for 6 h, then reduce it at 130 °C for 2 h.

[0047] Step (3): The graphene modified with natural latex was dispersed in 90% ethanol and washed three times to remove unreacted reagents. The water was changed every 4 hours. Finally, the washed graphene aerogel was freeze-dried under vacuum at -80℃ for 24 hours to obtain natural latex / graphene aerogel.

[0048] Example 3: A natural latex / graphene aerogel composite material for oil-water separation, the preparation method of which includes the following steps:

[0049] Step (1): Add 40 mg of graphene oxide solution to a beaker, sonicate for 30 min, remove and then add 0.8 mL of 50 mg / mL sodium dodecyl sulfate (SDS), 2 mL of 40 mg / mL ascorbic acid and 0.6 mL of 200 mg / mL natural latex in sequence. Then stir at 2500 rpm for 10 min to foam and obtain natural latex graphene composite.

[0050] Step (2): Transfer the natural latex graphene composite to a 25 mL reactor and react at 70 °C for 2 h. Remove it and freeze it at -18 °C for 6 h, then reduce it at 130 °C for 2 h.

[0051] Step (3): The graphene modified with natural latex was dispersed in 90% ethanol and washed three times to remove unreacted reagents. The water was changed every 4 hours. Finally, the washed graphene aerogel was freeze-dried under vacuum at -80℃ for 24 hours to obtain natural latex / graphene aerogel.

[0052] Comparative Example 1: The difference from Example 1 is that no natural latex is added, but the rest of the steps are the same to prepare graphene aerogel.

[0053] Comparative Example 2: The difference from Example 2 is that no natural latex is added, but the rest of the steps are the same to prepare graphene aerogel.

[0054] Comparative Example 3: The difference from Example 3 is that no natural latex is added, but the rest of the steps are the same to prepare graphene aerogel.

[0055] The large flake graphite used to prepare graphene oxide was prepared by CVD using MgO as a substrate, which was prepared in the laboratory.

[0056] All other reagents and raw materials are commercially available.

[0057] Weigh the samples tested in Examples 1-3 and Comparative Examples 1-3, and record the weight as M0; place a beaker containing 50 mL of oil phase reagent into a desiccator, place the sample into the beaker and evacuate, let it stand for 30 min to allow it to fully adsorb and reach saturation, take it out and place it on a copper grid to stand until the sample no longer drips, weigh it, and record the weight as M1; repeat the operation 3 times. The organic solvent tested is cyclohexane, and the adsorption amount Q of the composite material is calculated using formula (1); at the same time, 50% compression mechanical properties are tested. The results are shown in Table 1:

[0058]

[0059] Table 1 Adsorption capacity and compression pressure for the organic solvent cyclohexane

[0060] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Adsorption capacity (g / g) 69.1 102.7 54.9 79.3 118.2 114.8 Compression pressure kPa 15.2 7.0 12.8 15.0 4.8 6.8

[0061] Table 1 shows that the adsorption capacity of aerogels is affected by latex content and rotation speed. Examples 1-3 showed lower adsorption capacities for the organic solvent cyclohexane than Comparative Examples 1-3, indicating that the adsorption capacity decreases significantly with increasing latex content. This is because the aerogel itself is very lightweight; adding latex increases its density, weakening its low density advantage and thus reducing the adsorption capacity. However, when the rotation speed reaches 2000 rpm, the pressure required for Comparative Example 2 is minimized. The compression pressure of Examples 1-3 is much greater than that of Comparative Examples 1-3. The compressive strength of Example 2 is approximately 0.5 times higher than that of Comparative Example 2; the compressive strength of Example 3 is approximately 3 times higher than that of Comparative Example 2. Figure 7 a); As in Example 2, after 10 adsorption-extrusion cycles, the absorption capacity can still be retained at more than 92% of the initial value. Figure 6a) Although Comparative Examples 1-3 have large adsorption capacities, their compressive strength is weak, significantly reducing their recycling rate in practical applications of oily wastewater treatment, increasing costs and wasting resources. The reason is that embedding latex into graphene oxide allows for a strong bond between the latex network and the graphene oxide, improving compressive strength. This demonstrates that the natural latex / graphene aerogel prepared in this invention possesses excellent compressive strength and strong selective adsorption performance for various organic solvents.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A natural latex / graphene aerogel composite material for oil-water separation and its preparation method, wherein the natural latex / graphene aerogel composite material comprises, by weight: 0.5-1 parts graphene oxide solution or 0.5-1 parts graphene aerogel, 1-3 parts natural latex, and the mass ratio of natural latex / graphene aerogel in the composite material is 1:2-1:5; The preparation method of the modified natural latex / graphene aerogel includes the following steps: (1) Sodium dodecyl sulfate solution SDS, ascorbic acid, and natural latex were mixed in a graphene oxide solution to obtain a natural latex graphene precursor. (2) The natural latex graphene precursor was transferred to a 25mL reactor for hydrothermal reaction, and then frozen and reduced to obtain natural latex-modified graphene. (3) The graphene modified with natural latex was dispersed in 90% ethanol solution, soaked and washed, and then freeze-dried under vacuum to obtain a natural latex / graphene aerogel composite. The graphene aerogel also includes 0.8-1 parts of sodium dodecyl sulfate (SDS) and 1.5-2 parts of ascorbic acid; The graphene oxide was prepared from 2-5 parts of laboratory-purified large flake graphite, 1-5 parts of NaNO3, 20-30 parts of KMnO4, and 30-40 parts of H2O2.

2. The natural latex / graphene aerogel composite material for oil-water separation and its preparation method according to claim 1, characterized in that, The graphene oxide described in step (1) is prepared by the following steps: Laboratory-purified large-flake graphite was mixed with NaNO3 at a ratio of 2-3:1, and 200-250 mL of concentrated sulfuric acid was added to an ice-water bath. The mixture was stirred and reacted for 0.5 h. Then, 20-30 g of KMnO4 was slowly added, and the reaction was carried out at 10-15 °C for 0.5-1 h. The mixture was then poured into 1-2 L of distilled water and reacted at 80-100 °C for 15-60 min. The residual potassium permanganate and manganese dioxide were reduced to soluble manganese sulfate with 10-30% H2O2. After precipitation for 24 h, the unexfoliated graphite was removed by centrifugation, yielding a yellow-brown solution. This solution was then washed by centrifugation to remove SO4. 2- Graphene oxide was obtained.

3. The natural latex / graphene aerogel composite material for oil-water separation and its preparation method according to claim 1, characterized in that, The specific steps of step (1) are as follows: Sodium dodecyl sulfate (SDS), ascorbic acid, and natural latex were added to a graphene oxide solution that had been sonicated for 30 min. The solution was then stirred at 1000-2500 rpm for 10 min until foaming occurred, thus obtaining a natural latex graphene composite.

4. The natural latex / graphene aerogel composite material for oil-water separation and its preparation method according to claim 3, characterized in that, The mass ratio of graphene oxide to natural latex is 0.5-3:1, and the mass ratio of graphene oxide, SDS, and ascorbic acid is 0.5-1:0.8-1:1.5-2.

5. The natural latex / graphene aerogel composite material for oil-water separation and its preparation method according to claim 4, characterized in that, It is prepared by the preparation method described in any one of claims 1-4.

6. The natural latex / graphene aerogel composite material for oil-water separation according to claim 5, characterized in that... Applications for treating oily wastewater.

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