Graphene oil absorption material as well as preparation method and application thereof

Abstract

The invention relates to a graphene oil absorption material as well as a preparation method and application thereof, and the preparation method comprises the following steps: performing pulse discharge on graphene oxide aerogel to obtain the graphene oil absorption material. The method for preparing the graphene oil absorption material through pulse discharge provided by the invention is an efficient, rapid and energy-saving method for processing the oil absorption material, graphene oxide can be rapidly processed into the graphene oil absorption material at an extremely high speed in an extremely short time, and meanwhile, the product graphene oil absorption material is extremely fragile, and has a good application prospect. The composite material can be mixed with other additional functional materials for use, can be extruded and formed in various forms or can be pressed and covered on various carriers, and is wide in application range.

Description

Technical Field

[0001] The invention relates to the technical field of graphene oil absorbing material preparation, and in particular to a graphene oil absorbing material and a preparation method and application thereof. Background Art

[0002] Oil-absorbing materials have important application value in the fields of treating oil spills, environmental remediation, and treating industrial waste oil. As a new type of two-dimensional material, graphene oxide (GO) has been widely studied for use as an adsorption material due to its excellent mechanical properties, large specific surface area, and good chemical stability. However, untreated graphene oxide has a strong hydrophilicity, and its water absorption performance is better than its oil absorption performance. Therefore, it is difficult to be directly used in hydrophobic and lipophilic fields such as oil-water separation. In addition, the layered structure of graphene oxide also has certain limitations in terms of adsorption performance. Its interlayer stacking will result in a small specific surface area, which in turn affects its adsorption effect.

[0003] In response to these problems, in recent years, graphene oxide has been modified to improve its hydrophobicity and oil absorption performance. CN108774496A discloses a method for preparing a graphene-modified metal-based oleophilic and hydrophobic material with a surface area of ​​10-100 cm 2 , and the foam metal with many outstanding physical, chemical and mechanical properties as the matrix of oil-absorbing material graphene can greatly improve the mechanical properties of graphene adsorption material, and the contact angle with water is also above 110 °, but it adopts liquid phase and reduction method preparation, the overall preparation process is complicated and cumbersome, and it is impossible to quickly realize large-scale preparation, and the foam metal has a certain hardness, and extrusion molding is relatively difficult, and it is impossible to meet the use with different carriers. CN112791697A discloses a kind of elastic super hydrophobic graphene gel ball and its preparation method and application, to solve the adsorption and recovery problem of marine oil spills and other organic pollutants, including mixing graphene oxide aqueous dispersion with hydrophobic amine gel bath, and obtaining elastic graphene oxide gel ball after treatment, and its surface water contact angle reaches 153 °. But it still adopts liquid phase method preparation, the overall preparation process is complicated and cumbersome, and it is impossible to quickly realize large-scale preparation, and elastic gel ball is also not conducive to extrusion molding and loading on various carriers.

[0004] Therefore, how to provide a method that can quickly and efficiently achieve large-scale preparation of graphene oil-absorbing materials, and the prepared graphene oil-absorbing materials have stronger selectivity for oil and are more suitable for use in various scenarios, is a technical problem that needs to be solved urgently. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a graphene oil-absorbing material and a preparation method and application thereof. The method for preparing graphene oil-absorbing material by pulse discharge provided by the present invention is an efficient, rapid and energy-saving method for preparing graphene oil-absorbing material, which can quickly process graphene oxide into graphene oil-absorbing material at an extremely high speed in a very short time, and the product graphene oil-absorbing material is extremely fragile, which is conducive to its mixing with other additional functional materials, and is more conducive to its extrusion molding in various forms or pressing on various carriers, and has a wider range of uses.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a graphene oil-absorbing material, the preparation method comprising the following steps:

[0008] After pulse discharge of graphene oxide aerogel, graphene oil absorbing material is obtained.

[0009] Pulse discharge technology is a high-speed and efficient heat treatment method. Under certain current and voltage, it can generate high temperature (instantaneous high temperature) in a very short time, changing the surface / internal structure and chemical properties of the material. In the present invention, most of the oxygen-containing functional groups in the graphene oxide aerogel are removed by the instantaneous high temperature treatment method of pulse discharge, and the interlayer spacing of the obtained graphene oil-absorbing material is significantly increased, and the specific surface area is large, thus giving the material hydrophobic and oleophilic properties, which can not only efficiently adsorb oil substances, but also show good selectivity in oil-water mixed systems.

[0010] The pulse discharge processing method of the present invention is simple, convenient, high-speed, efficient, and energy-saving. The obtained product, graphene oil-absorbing material, has broad application prospects and is simple to use, and has stronger selectivity for oil. Its powder can be prepared into adsorption materials suitable for various situations (different shapes) through molding treatment, and can also be pressed on a carrier with special functions, so that various carriers can be used for the separation of oil and water in an oil-water mixture. Moreover, the entire preparation process does not contain any dangerous or harmful products, which is convenient and more environmentally friendly.

[0011] The raw material used in the pulse discharge of the present invention is graphene oxide aerogel. The aerogel has a loose and porous structural characteristic. During the pulse discharge process, it is easier to heat the inside of the material in an instant (in a very short time). The material is heated more evenly, so that it can be more completely converted into the product graphene oil-absorbing material, avoiding the phenomenon that only the surface is converted without obvious changes inside, affecting the preparation effect of the graphene oil-absorbing material, and then affecting its use as an oil-absorbing material and the overall oil-absorbing effect.

[0012] As a preferred technical solution of the present invention, the density of the graphene oxide aerogel is 3 mg / cm3 -80mg / cm 3 , for example 3mg / cm 3 , 5mg / cm 3 、10mg / cm 3 、15mg / cm 3 , 20mg / cm 3 , 25mg / cm 3 、30mg / cm 3 、35mg / cm 3 , 40mg / cm 3 , 45mg / cm 3 、50mg / cm 3 、55mg / cm 3 、60mg / cm 3 、65mg / cm 3 、70mg / cm 3 、75mg / cm 3 or 80mg / cm 3 wait.

[0013] Preferably, the specific surface area of ​​the graphene oxide aerogel is 50 m 2 / g-300m 2 / g, for example 50m 2 / g, 80m 2 / g、100m 2 / g, 120m 2 / g, 150m 2 / g, 180m 2 / g, 200m 2 / g, 220m 2 / g, 250m 2 / g, 280m 2 / g or 300m 2 / g, etc.

[0014] The present invention regulates the density and specific surface area of ​​graphene oxide aerogel, so that after pulse discharge, graphene oxide can be converted into graphene oil-absorbing material more thoroughly, avoiding the phenomenon of partial conversion, thereby improving the overall oil absorption effect of the material and better realizing the separation of water and oil.

[0015] Preferably, the specific surface area of ​​the graphene oil absorbing material is 450 m 2 / g-1000m 2 / g, for example 450m 2 / g, 550m 2 / g, 650m 2 / g, 750m 2 / g, 850m 2 / g, 950m 2 / g or 1000m 2 / g, etc.

[0016] Preferably, the graphene oxide aerogel further comprises additives.

[0017] It should be noted that the present invention does not make specific requirements and special limitations on the types of the additives. Additives are added to the graphene oxide aerogel. The addition of different additives can make the graphene oil-absorbing material containing additives have different additional functions. For example, the addition of nanosilver can make the graphene oil-absorbing material have a bactericidal effect, the addition of transition metals such as Pt or Pd can make the graphene oil-absorbing material have a catalytic function, and the addition of MOF can increase the oil-water separation effect of the graphene oil-absorbing material. Those skilled in the art can make adaptive selections and adjustments according to actual conditions.

[0018] As a preferred technical solution of the present invention, the raw material for preparing the graphene oxide aerogel includes graphene oxide.

[0019] It should be noted that the method for preparing the graphene oxide aerogel from the graphene oxide in the present invention is not specifically limited, as long as the density of the graphene oxide aerogel reaches 3 mg / cm 3 -80mg / cm 3 , the specific surface area reaches 50m 2 / g-300m 2 / g, for example, it can be any one of freeze-drying, hydrothermal self-assembly or water bath heating self-assembly.

[0020] Exemplarily, the present invention provides a method for preparing graphene oxide aerogel, the preparation method comprising the following steps:

[0021] After the graphene oxide was cleaned, it was subjected to freezing and drying processes in sequence to obtain a density of 3 mg / cm 3 -80mg / cm 3 , specific surface area is 50m 2 / g-300m 2 / g of graphene oxide aerogel;

[0022] or,

[0023] After the graphene oxide was cleaned, the additives were added and ultrasonically mixed, and then the freezing process and the drying process were carried out in sequence to obtain a density of 3 mg / cm 3 -80mg / cm 3 , specific surface area is 50m 2 / g-300m 2 / g of graphene oxide aerogel (including additives).

[0024] It should be noted that the present invention does not make any specific requirements or special restrictions on the temperature and time of the freezing process and the drying process. As long as the density of the graphene oxide aerogel reaches 3 mg / cm 3 -80mg / cm 3 , the specific surface area reaches 50m 2 / g-300m 2 / g, for example, the temperature of the freezing process can be -70°C to -90°C, the time of the freezing process can be 20h-28h, the temperature of the drying process can be -45°C to -60°C, and the time of the drying process can be 48h-72h.

[0025] It should be noted that the graphene oxide used in the present invention can be a commercially available product, or it can be prepared by known methods, such as chemical oxidation (Hummers method), physical exfoliation (mechanical or liquid phase exfoliation) or electrochemical method. Those skilled in the art can make adaptive selections and adjustments based on actual conditions.

[0026] As a preferred technical solution of the present invention, before the pulse discharge, the graphene oxide aerogel is wrapped with graphite paper.

[0027] Preferably, the pulse discharge is performed under a protective atmosphere.

[0028] Preferably, the gas used for the protective atmosphere includes argon or nitrogen.

[0029] As a preferred technical solution of the present invention, the voltage of the pulse discharge is 20V-40V, for example, 20V, 22V, 24V, 26V, 28V, 30V, 32V, 34V, 36V, 38V or 40V.

[0030] As a preferred technical solution of the present invention, the current of the pulse discharge is 70A-100A, for example, 70A, 72A, 75A, 78A, 80A, 82A, 85A, 88A, 90A, 92A, 95A, 98A or 100A, etc.

[0031] As a preferred technical solution of the present invention, the time of the pulse discharge is 1s-2s, for example, 1s, 1.1s, 1.2s, 1.3s, 1.4s, 1.5s, 1.6s, 1.7s, 1.8s, 1.9s or 2s.

[0032] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0033] Density is 3mg / cm 3 -80mg / cm 3, specific surface area is 50m 2 / g-300m 2 / g of graphene oxide aerogel was pulsed for 1s-2s at a voltage of 20V-40V and a current of 70A-100A to obtain a specific surface area of ​​450m 2 / g-1000m 2 / g of graphene oil-absorbing material.

[0034] In a second aspect, the present invention further provides a graphene oil-absorbing material, which is prepared by the preparation method described in the first aspect.

[0035] In a third aspect, the present invention further provides an application of a graphene oil-absorbing material, wherein the graphene oil-absorbing material prepared by the preparation method described in the first aspect, or the graphene oil-absorbing material described in the second aspect, is applied to the separation of oil and water in an oil-water mixture.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects:

[0037] 1) The present invention adopts an efficient, rapid and energy-saving method for preparing graphene oil-absorbing materials. By pulse discharge, graphene oxide can be quickly processed into graphene oil-absorbing materials at an extremely high speed in a very short time. At the same time, the product graphene oil-absorbing material is extremely fragile, which is conducive to its mixing with other additional functional materials, and is more conducive to its extrusion molding in various forms or pressing on various carriers, and has a wider range of uses.

[0038] 2) After the product graphene oil-absorbing material of the present invention is compacted under the same pressure of 500 MPa, the contact angle of water and the contact angle of oil are quite different, and the contact angle of oil is between 18° and 25°, which further indicates that the graphene oil-absorbing material obtained by the preparation method of the present invention has more obvious oil absorption and hydrophobicity.

[0039] 3) The present invention provides different compaction pressures to compact the product graphene oil-absorbing material, and can obtain oil-absorbing and hydrophobic tools for different situations, so as to separate oil-water mixtures with different characteristics, and has a wider range of uses. For example, the graphene oil-absorbing material is crushed and loaded into a carrier such as a funnel capillary, a colander, a filter screen or a pipe, and after being compacted with different pressures, it can be used to separate oil-water mixtures with different viscosities. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is an XPS comparison chart of the graphene oil-absorbing material and graphene oxide aerogel material prepared in Example 1 and Comparative Example 3 of the present invention.

[0041] Figure 2 It is an adsorption-desorption curve diagram of the graphene oil-absorbing material prepared in Example 1 of the present invention.

[0042] Figure 3 This is the pore size distribution diagram of the graphene oil-absorbing material prepared in Example 1 of the present invention.

[0043] Figure 4 It is an adsorption-desorption curve diagram of the graphene oxide aerogel prepared in Comparative Example 3 of the present invention.

[0044] Figure 5 This is the pore size distribution diagram of the graphene oxide aerogel prepared in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0046] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0047] The graphene oxide used in the specific implementation of the present invention is a commercially available product purchased from Changzhou Sixth Element Materials Technology Co., Ltd., with product model SE2430SW-N and production batch number A4195ARA.

[0048] The pulse discharge equipment used in the present invention is manufactured by Taiyuan Saiyin New Materials Co., Ltd. and its model is FJH-2024A.

[0049] Example 1

[0050] This embodiment provides a method for preparing a graphene oil-absorbing material, the preparation method comprising the following steps:

[0051] (1) washing the graphene oxide: adding graphene oxide to deionized water to obtain graphene oxide slurry, adding one-third of the volume of the graphene oxide slurry into a centrifuge tube, and then adding deionized water into the centrifuge tube to two-thirds of the volume of the centrifuge tube, shaking on an oscillator for 5 minutes, and then placing it in a centrifuge, setting the speed to 10000 rpm, centrifuging for 20 minutes, and repeatedly washing until it is close to neutral;

[0052] The cleaned graphene oxide was placed in a -80°C refrigerator and frozen for 24 h. The frozen graphene oxide was then placed in a freeze dryer and dried at -50°C for 48 h. The density of the graphene oxide was 50 mg / cm 3 , specific surface area is 66m 2 / g of graphene oxide aerogel;

[0053] (2) The graphene oxide aerogel was wrapped with graphite paper, placed in the reaction chamber of the pulse discharge equipment and evacuated to a vacuum reading of -0.1 MPa. The pulse discharge parameters were set to a voltage of 36 V and a current of 83 A for 1 s, and the specific surface area was obtained to be 506 m 2 / g of graphene oil-absorbing material.

[0054] Example 2

[0055] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (2), the parameters of the pulse discharge are set to a voltage of 40 V and a current of 90 A, and the remaining preparation methods and parameters are consistent with those of the embodiment 1, and a specific surface area of ​​603 m 2 / g of graphene oil-absorbing material.

[0056] Example 3

[0057] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (1), drying is performed for 72 hours to obtain a graphene oil-absorbing material with a density of 30 mg / cm 3 , specific surface area is 85m 2 / g of graphene oxide aerogel, in step (2), the pulse discharge parameters are set to voltage 40V, current 90A, and the remaining preparation methods and parameters are consistent with those in Example 1, and a specific surface area of ​​663m 2 / g of graphene oil-absorbing material.

[0058] Example 4

[0059] The present embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (1), a hydrothermal self-assembly method is used to disperse graphene oxide in deionized water to obtain a graphene oxide slurry, and then a hydrothermal reaction is carried out at 180° C. for 18 h, and the slurry is cooled to room temperature to obtain a graphene oxide hydrogel. After washing and freeze-drying, the slurry is calcined at 1000° C. for 120 min under nitrogen protection, and the slurry is cooled to room temperature to obtain a self-molded graphene with a density of 40 mg / cm 3 , specific surface area is 74m 2 / g of graphene oxide aerogel, the rest of the preparation method and parameters were consistent with those in Example 1, and a specific surface area of ​​480m 2 / g of graphene oil-absorbing material.

[0060] Example 5

[0061] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (1), the washed graphene oxide and the nanosilver dispersion (nanosilver mass fraction is 0.1wt%) are ultrasonically mixed and then freeze-dried together to obtain a graphene oil-absorbing material with a density of 50mg / cm 3 , specific surface area is 66m 2 / g of graphene oxide aerogel containing nanosilver (because the amount of nanosilver added is very small, it will basically not have a significant impact on the density, and its impact can be ignored), the rest of the preparation method and parameters are consistent with Example 1, and the specific surface area is 508m 2 / g of graphene oil-absorbing material.

[0062] In this embodiment, nanosilver is added to the graphene oxide aerogel, so that the graphene oil-absorbing material after pulse discharge has a bactericidal property, so that it can have a bactericidal effect while separating oil and water, which is more conducive to the long-term maintenance of the graphene oil-absorbing material.

[0063] Example 6

[0064] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (2), the parameters of the pulse discharge are set to voltage 20V, current 100A, and discharge 1.5s. The remaining preparation methods and parameters are consistent with the embodiment 1, and the specific surface area is 500m 2 / g of graphene oil-absorbing material.

[0065] Example 7

[0066] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (2), the parameters of the pulse discharge are set to voltage 40V, current 70A, and discharge 2s. The remaining preparation methods and parameters are consistent with the embodiment 1, and the specific surface area is 612m 2 / g of graphene oil-absorbing material.

[0067] Example 8

[0068] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (2), the parameters of the pulse discharge are set to a voltage of 50 V and a current of 110 A, and the remaining preparation methods and parameters are consistent with those of the embodiment 1, and a specific surface area of ​​825 m 2 / g of graphene oil-absorbing material.

[0069] Example 9

[0070] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (2), the parameters of the pulse discharge are set to voltage 10V and current 60A, and the remaining preparation methods and parameters are consistent with the embodiment 1, and the specific surface area is 371m 2 / g of graphene oil-absorbing material.

[0071] Example 10

[0072] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (2), the pulse discharge time is set to 0.5s, and the other preparation methods and parameters are consistent with the embodiment 1, and the specific surface area is 319m 2 / g of graphene oil-absorbing material.

[0073] Embodiment 11

[0074] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (1), drying is performed for 96 hours to obtain a graphene oil-absorbing material with a density of 2 mg / cm 3 , specific surface area is 311m 2 / g of graphene oxide aerogel, the rest of the preparation method and parameters were consistent with those in Example 1, and a specific surface area of ​​620m 2 / g of graphene oil-absorbing material.

[0075] Example 12

[0076] This embodiment provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and the embodiment 1 is that in step (1), drying for 40 hours is performed to obtain a graphene oil-absorbing material with a density of 84 mg / cm 3 , specific surface area is 40m 2 / g of graphene oxide aerogel, the rest of the preparation method and parameters were consistent with those in Example 1, and a specific surface area of ​​457m 2 / g of graphene oil-absorbing material.

[0077] Comparative Example 1

[0078] This comparative example provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and Example 1 is that in step (2), the graphene oxide aerogel is heated in a tubular furnace at 1000° C. for 2 h in a nitrogen atmosphere. The remaining preparation methods and parameters are consistent with those in Example 1, and a specific surface area of ​​510 m 2 / g of graphene oil-absorbing material.

[0079] Comparative Example 2

[0080] This comparative example provides a method for preparing a graphene oil-absorbing material. The difference between the preparation method and Example 1 is that the freeze-drying step in step (1) is omitted, the washed graphene oxide is directly dried, and the obtained dried graphene oxide is pulse-discharged. The remaining preparation methods and parameters are consistent with those in Example 1, and a graphene oil-absorbing material with a specific surface area of ​​40 m 2 / g of graphene oil-absorbing material.

[0081] Comparative Example 3

[0082] This comparative example provides a method for preparing a graphene oxide aerogel material. The difference between the preparation method and Example 1 is that step (2) is omitted, and the remaining preparation methods and parameters are consistent with Example 1, and a density of 50 mg / cm 3 , specific surface area is 66m 2 / g of graphene oxide aerogel material.

[0083] The graphene oil-absorbing materials prepared in Examples 1-12 and Comparative Examples 1-2 and the graphene oxide aerogel material provided in Comparative Example 3 were compacted under a pressure of 500 MPa, and the contact angles to water and oil were measured respectively. The contact angle test steps are as follows:

[0084] Glass sheets were used to load the graphene oil-absorbing materials of Examples 1-12 and Comparative Examples 1-2, and the graphene oxide aerogel of Comparative Example 3, respectively. Droplets of water and oil (added separately) with a volume of 20 μL were vertically dropped at a certain distance directly above the materials. A contact angle tester was used to continuously take pictures, and frames were taken for contact angle testing. The same sample was tested 5 times and the average value was taken. The specific test results are shown in Table 1.

[0085] Figure 1 The XPS comparison chart of the graphene oil-absorbing material and the graphene oxide aerogel material prepared in Example 1 of the present invention and Comparative Example 3 is shown. It can be seen from the figure that the oxygen content of the graphene oil-absorbing material drops sharply, and the C / O changes from 2.26 to 18.51, indicating that after the pulse discharge of the graphene oxide aerogel, most of the oxygen-containing functional groups are removed, so that the material is transformed into an oil-absorbing and hydrophobic material.

[0086] Figure 2 The adsorption-desorption curve of the graphene oil-absorbing material prepared in Example 1 of the present invention is shown. Figure 3 The pore size distribution diagram of the graphene oil absorbing material prepared in Example 1 of the present invention is shown. Figure 4 The adsorption-desorption curve of the graphene oxide aerogel prepared in Comparative Example 3 of the present invention is shown. Figure 5The pore size distribution diagram of the graphene oxide aerogel prepared in Comparative Example 3 of the present invention is shown. From the comparison of the figures, it can be seen that the mesopore distribution of the graphene oil-absorbing material is significantly improved. When the mesopore range is increased, the specific surface area of ​​the material is increased, and the adsorption capacity of polar molecules is enhanced. The mesopore or macropore structure makes it easier for non-polar molecules to be adsorbed, thereby increasing the hydrophobicity of the material.

[0087] Table 1

[0088] project Contact angle to water (°) Contact angle to oil (°) Example 1 112.7 23.73 Example 2 121.6 20.52 Example 3 128.9 19.85 Example 4 117.6 22.66 Example 5 110.8 23.98 Example 6 115.2 23.43 Example 7 129.3 19.02 Example 8 130.1 18.94 Example 9 98.8 49.28 Example 10 102.4 43.28 Embodiment 11 111.3 23.68 Example 12 100.49 49.78 Comparative Example 1 108.67 25.08 Comparative Example 2 84.65 50.96 Comparative Example 3 80.84 52.31

[0089] The test results show that:

[0090] (1) It can be seen from Examples 1-7 that the method for preparing graphene oil-absorbing material by pulse discharge in the present invention can rapidly process graphene oxide into graphene oil-absorbing material at an extremely high speed. At the same time, the product graphene oil-absorbing material is extremely fragile, which is conducive to its mixing with other additional functional materials and is more conducive to its extrusion molding in various forms or pressing on various carriers, and has a wider range of uses. Under a compaction pressure of 500 MPa, the contact angle of water and the contact angle of oil are quite different, and the contact angle of oil is between 18° and 25°, which significantly enhances the ability of oil absorption and hydrophobicity, and can better achieve the effect of oil absorption and hydrophobicity.

[0091] (2) It can be seen from Examples 1 and 8-9 that the instantaneous temperature of the pulse discharge can be better regulated within a certain range by further regulating the voltage of the pulse discharge to 20V-40V and the current to 70A-100A, so that most of the oxygen-containing functional groups are removed, the interlayer spacing of the material is increased, and the graphene oil-absorbing material has a better oil-absorbing and hydrophobic effect. If the voltage and current are both too low, the instantaneous temperature is low, and the material cannot be completely converted into the graphene oil-absorbing material, and the improvement in the oil-absorbing and hydrophobic ability is not obvious; if the voltage and current are both too high, although the oil-absorbing and hydrophobic ability of the material is enhanced, due to the high instantaneous temperature, the graphene oil-absorbing material is too loose, which will lead to material loss and difficulty in compression molding in the actual application in various carriers.

[0092] (3) It can be seen from Examples 1 and 10 that the present invention can achieve complete conversion of the material into graphene oil-absorbing material by further adjusting the pulse discharge time to 1s-2s. If the pulse discharge time is short, the conversion of graphene oxide into graphene oil-absorbing material will not be complete, thereby affecting the oil absorption effect. If the pulse discharge time is long, it will not further play a positive role in enhancing the oil absorption effect of the graphene oil-absorbing material, but will lead to energy waste, which is not conducive to energy saving.

[0093] (4) It can be seen from Examples 1 and 11-12 that the present invention can make the conversion of graphene oxide into graphene oil-absorbing material more thorough after pulse discharge by further regulating the density and specific surface area of ​​graphene oxide aerogel, thereby avoiding the phenomenon of partial conversion, thereby significantly enhancing the oil absorption and hydrophobicity ability, and better realizing the separation of water and oil. If the density of graphene oxide aerogel is too low, the graphene oil-absorbing material obtained after pulse discharge will become very fine dust and cannot be used in the vehicle; if the density of graphene oxide aerogel is too high, only the surface or part of the graphene oxide will be converted into the graphene oil-absorbing material, and a thorough conversion cannot be achieved.

[0094] (5) It can be seen from Example 1 and Comparative Example 1 that the pulse discharge of the present invention is an efficient, fast and energy-saving method for processing oil-absorbing materials. It can quickly process graphene oxide into graphene oil-absorbing materials at an extremely high speed in an extremely short time. When other heat treatment methods are used, it cannot be guaranteed that graphene oil-absorbing materials with better performance can be prepared in large quantities in an extremely short time (within 1s-2s).

[0095] (6) It can be seen from Example 1 and Comparative Example 2 that the present invention uses pulse discharge on the aerogel state of graphene oxide. The aerogel has a loose and porous structural characteristic. During the pulse discharge process, it is easier to heat the inside of the material in an instant (in a very short time). The material is heated more evenly, so that it can be more completely converted into the product graphene oil-absorbing material, avoiding the phenomenon that only the surface is converted without obvious changes inside, affecting the preparation effect of the graphene oil-absorbing material, and then affecting its use as an oil-absorbing material and the overall oil absorption effect.

[0096] (7) It can be seen from Example 1 and Comparative Example 3 that, compared with the graphene oxide aerogel without pulse discharge, the oil absorption and hydrophobicity of the graphene oil-absorbing material after pulse discharge has undergone a great change, the oil absorption and hydrophobicity is more obvious, and the selectivity for oil is higher.

[0097] In summary, the method for preparing graphene oil-absorbing material by pulse discharge provided by the present invention is an efficient, fast and energy-saving method for preparing graphene oil-absorbing material. Graphene oxide can be quickly processed into graphene oil-absorbing material at an extremely high speed in a very short time. At the same time, the product graphene oil-absorbing material is extremely fragile, which is conducive to its mixing with other additional functional materials, and is more conducive to its extrusion molding in various forms or pressing on various carriers, and has a wider range of uses.

[0098] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a graphene oil-absorbing material, characterized in that: The preparation method comprises the following steps: After pulse discharge of graphene oxide aerogel, graphene oil absorbing material is obtained.

2. The preparation method according to claim 1, characterized in that: The density of the graphene oxide aerogel is 3 mg / cm 3 -80mg / cm 3 ; Preferably, the specific surface area of ​​the graphene oxide aerogel is 50 m 2 / g-300m 2 / g; Preferably, the specific surface area of ​​the graphene oil absorbing material is 450 m 2 / g-1000m 2 / g; Preferably, the graphene oxide aerogel further comprises additives.

3. The preparation method according to claim 1 or 2, characterized in that: The raw material for preparing the graphene oxide aerogel includes graphene oxide.

4. The preparation method according to any one of claims 1 to 3, characterized in that The pulse discharge is carried out under a protective atmosphere; Preferably, the gas used for the protective atmosphere includes argon or nitrogen.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The voltage of the pulse discharge is 20V-40V.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The current of the pulse discharge is 70A-100A.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The pulse discharge time is 1s-2s.

8. The preparation method according to claim 1, characterized in that: The preparation method comprises the following steps: Density is 3mg / cm 3 -80mg / cm 3 , specific surface area is 50m 2 / g-300m 2 / g of graphene oxide aerogel was pulsed for 1s-2s at a voltage of 20V-40V and a current of 70A-100A to obtain a specific surface area of ​​450m 2 / g-1000m 2 / g of graphene oil-absorbing material.

9. A graphene oil-absorbing material, characterized in that: The graphene oil-absorbing material is prepared by the preparation method according to any one of claims 1 to 8.

10. An application of a graphene oil-absorbing material, characterized in that: The graphene oil-absorbing material prepared by the preparation method according to any one of claims 1 to 8, or the graphene oil-absorbing material according to claim 9, is applied to the separation of oil and water in an oil-water mixture.

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