CN115155546A

CN115155546A - Graphene oxide, preparation method thereof, method for adsorbing unsymmetrical dimethylhydrazine in aqueous solution by using graphene oxide and application of graphene oxide

Info

Publication number: CN115155546A
Application number: CN202210802346.8A
Authority: CN
Inventors: 贾瑛; 汪浩洋; 吕晓猛; 沈可可; 金国锋
Original assignee: Rocket Force University of Engineering of PLA
Current assignee: Rocket Force University of Engineering of PLA
Priority date: 2022-07-07
Filing date: 2022-07-07
Publication date: 2022-10-11
Anticipated expiration: 2042-07-07
Also published as: CN115155546B

Abstract

The invention discloses graphene oxide, a preparation method thereof, a method for adsorbing unsymmetrical dimethylhydrazine in an aqueous solution by using the graphene oxide, and an application of the graphene oxide, and belongs to the technical field of aerospace fuel safety treatment. The invention provides a graphene oxide exogenous additive structure based on a first principle, and a carboxyl-rich graphene oxide material is prepared and synthesized by adopting an improved Hummers method; the method for inhibiting the unsymmetrical dimethylhydrazine in the aqueous solution from escaping based on the carboxyl-rich graphene oxide material is provided, and the unsymmetrical dimethylhydrazine leakage accident is treated by using the method, so that the maximum escaping amount of the unsymmetrical dimethylhydrazine gas is reduced, and more precious time is won for subsequent emergency rescue work; aiming at the follow-up requirements of emergency treatment, on the basis of not excessively damaging the escape inhibiting capability of the carboxyl-rich graphene oxide, the green and recyclable performance of the escape inhibitor added from an external source is increased by loading the ferroferric oxide magnetic material.

Description

Graphene oxide, preparation method thereof, method for adsorbing unsymmetrical dimethylhydrazine in aqueous solution by using graphene oxide and application of graphene oxide

Technical Field

The invention relates to the technical field of aerospace fuel safety treatment, in particular to carboxyl-rich graphene oxide, preparation thereof, a method for adsorbing unsymmetrical dimethylhydrazine in an aqueous solution by using the same and application thereof.

Background

With the increasing frequency of aerospace launch activities worldwide, the demand and frequency of use of various hydrazine-based fuels has also increased. Unsymmetrical Dimethylhydrazine (UDMH), a widely used hydrazine fuel, has the outstanding characteristics of flammability, explosiveness, high toxicity, strong corrosivity and the like, and the safety problem of the Unsymmetrical Dimethylhydrazine (UDMH) in a launching site or a storage reservoir is always highly concerned by related personnel. Among many safety accidents, leakage accidents are most concerned due to great difficulty in prevention, many accident causes, high occurrence frequency and great harm. Accidents represent UDMH leakage accidents with strong randomness, burstiness, diversity, severe harm and intractable. The existing dangerous chemical safety management theory and method can not comprehensively estimate the reason, type, time and place of the leakage accident, and completely eradicating the leakage accident is unrealistic. Therefore, when a leakage accident happens suddenly, how to adopt an effective emergency treatment mode to quickly prevent or slow down the propagation and diffusion of toxic substances, reduce the harm caused by the accident and strive for precious time for the development of subsequent emergency rescue activities becomes a key point.

The existing UDMH storage places mostly select a water spraying device to deal with the leakage risk of the propellant, and the device utilizes the characteristic that the UDMH is easy to dissolve in water, reduces the diffusion speed of the unsymmetrical dimethylhydrazine toxic gas by a water curtain absorption method, and reduces the harm caused by leakage accidents. However, a large amount of unsymmetrical dimethylhydrazine aqueous solution with a large volatilization area is formed inside the whole storage place by the treatment mode, and experimental researches show that toxic substances in the aqueous solution can continuously escape into the air, pollute the surrounding environment and threaten the life health safety of rescue workers. Therefore, the construction of a material and a method for treating the unsymmetrical dimethylhydrazine leakage accident and reducing the unsymmetrical dimethylhydrazine gas escape amount is very important.

Disclosure of Invention

The invention provides graphene oxide, a preparation method thereof, a method for adsorbing unsymmetrical dimethylhydrazine in an aqueous solution by using the graphene oxide and an application of the graphene oxide, and aims to solve the technical problems that toxic substances escape to the air, the surrounding environment is polluted and the life health and safety of rescue workers are threatened due to the volatilization of unsymmetrical dimethylhydrazine in the unsymmetrical dimethylhydrazine aqueous solution treatment process in the prior art; meanwhile, aiming at the practical problem that the escaping phenomenon of the unsymmetrical dimethylhydrazine during the water spraying treatment is avoided, the escaping phenomenon of the unsymmetrical dimethylhydrazine during the emergency treatment is inhibited by introducing an exogenous additive.

One of the purposes of the present invention is to provide a preparation method of graphene oxide.

The main technical scheme comprises the following steps: structural design and preparation of graphene oxide; the structure design of the graphene oxide is based on a Density Functional Theory (DFT) method; preparing graphene oxide, namely preparing carboxyl-rich graphene oxide; the preparation method of the carboxyl-rich graphene oxide mainly comprises the steps of mixing natural graphite powder and concentrated sulfuric acid, adding potassium permanganate into an ice water bath, stirring with polytetrafluoroethylene, carrying out water treatment, carrying out high-temperature reaction on the graphene oxide, adding hydrogen peroxide, carrying out suction filtration to obtain a filter cake, and stirring and dispersing to obtain a graphite oxide water system dispersion liquid.

Further, the graphene oxide structure design based on the Density Functional Theory (DFT) method comprises the steps of calculating by using Simulation software based on Ab-initio Simulation Package software (VASP5.4.4), wherein the Vienna Ab-initio Simulation Package software (VASP5.4.4) is the existing commercially available software; and calculating the electron exchange related potential by adopting Generalized Gradient Approximation (GGA), and selecting Perew-Burke-Ernzerhof (PBE) for pseudopotential analysis.

Further, the preparation method of the carboxyl-rich graphene oxide comprises the following steps:

s101, slowly mixing 0.5-1.5 g of natural graphite powder and 40-50 mL of concentrated sulfuric acid in a three-neck flask and uniformly stirring;

s102, slowly adding 2.0-4.0 g of potassium permanganate into a three-neck flask in a medicine spoon for multiple times, cooling in ice water bath, and violently stirring by using a polytetrafluoroethylene stirring paddle at 100-300 rpm;

s103, adding 1-3 mL of deionized water, and stirring until the graphite flakes are uniformly dispersed in the system;

s104, after the system is cooled, putting the reaction system into a constant-temperature water bath device at the temperature of 30-50 ℃, and stirring for 60-120 minutes at the speed of 200-400 rpm;

s105, after the middle-temperature oxidation process at 30-50 ℃, slowly adding 50-150 mL of deionized water into the reaction system, heating to 80-98 ℃, and continuing to react for 10-20 minutes;

s106, after the oxidation process is finished, slowly pouring the reaction liquid into a beaker filled with 0.1-0.3L of deionized water, and then dropwise adding hydrogen peroxide (3-8 mL, 30%) until the color of the suspension is changed from brown to yellow;

s107, carrying out suction filtration on the suspension, and washing away residual manganese ions and potassium ions by using hydrochloric acid through an aqueous solution (25 mL-75mL, 1 time-3 times) diluted by 1;

and S108, after drying the filter cake, tearing off the filter cake, stirring the filter cake overnight by using 0.25L-0.75L of deionized water, and dispersing the filter cake to obtain graphite oxide water system dispersion liquid.

Further, preparing carboxyl-rich graphene oxide by loading ferroferric oxide and preparing carboxyl-rich graphene oxide; the preparation method comprises the following steps:

s201, slowly mixing 0.5-1.5 g of natural graphite powder and 40-50 mL of concentrated sulfuric acid in a three-neck flask and uniformly stirring;

s202, slowly adding 2.0 g-4.0 g of potassium permanganate into a three-neck flask in a medicine spoon mode, cooling in ice water bath, and violently stirring with a polytetrafluoroethylene stirring paddle at 100-300 rpm;

s203, adding 1-3 mL of deionized water, and stirring until the graphite flakes are uniformly dispersed in the system;

s204, after the system is cooled, putting the reaction system into a constant-temperature water bath device at the temperature of 30-50 ℃, and stirring for 60-120 minutes at the speed of 200-400 rpm;

s205, after the medium temperature oxidation process at 30-50 ℃, slowly adding 50-150 mL deionized water into the reaction system, and heating to 80-98 ℃ to continue the reaction for 10-20 minutes;

s206, after the oxidation process is finished, slowly pouring the reaction liquid into a beaker filled with 0.1-0.3L of deionized water, and then dropwise adding hydrogen peroxide (3-8 mL, 30%) until the color of the suspension is changed from brown to yellow;

s207, carrying out suction filtration on the suspension, and washing away residual manganese ions and potassium ions by using hydrochloric acid through an aqueous solution (25 mL-75mL, 1 time-3 times) diluted by 1;

s208, after drying the filter cake, tearing off the filter cake, stirring the filter cake with 0.25-0.75L of deionized water for overnight dispersion, and obtaining graphite oxide water system dispersion liquid;

s209, obtaining carboxyl-rich graphene oxide solid powder in a freeze-drying treatment mode;

s210, taking a proper amount of carboxyl-rich graphene oxide and 25-75 mL of ethylene glycol to mix in advance for later use;

s211, feCl ₃ ·6H ₂ Adding O into a prepared carboxyl-rich graphene oxide and ethylene glycol solution, and carrying out ultrasonic treatment for 2-4 h;

s212, after the ultrasonic treatment is finished, adding sodium acetate, wherein the ratio of sodium acetate to ferric ions is (5);

s213, stirring at 100-300 rpm by using a polytetrafluoroethylene stirring paddle, and heating and refluxing for 8-12 h after uniform stirring;

s214, centrifuging, and washing for 1 to 3 times by using pure water and ethylene glycol;

s215, vacuum drying is carried out for 6-10 hours, and the carboxyl-rich graphene oxide powdery solid loaded with ferroferric oxide is obtained.

The second objective of the present invention is to provide a graphene oxide.

The graphene oxide is prepared by the preparation method of the graphene oxide; the graphene oxide is carboxyl-rich graphene oxide; preferably, the carboxyl-rich graphene oxide is flanked by carboxyl functional groups.

Furthermore, the STM image of the carboxyl-rich graphene oxide has obvious wrinkle shape; preferably, the size distribution of the carboxyl-rich graphene oxide is between 0 and 25 μm.

Further, the carboxyl-rich graphene oxide is loaded with ferroferric oxide carboxyl-rich graphene oxide; preferably, the loaded ferroferric oxide carboxyl-rich graphene oxide SEM image covers spherical particles in folds.

The third purpose of the invention is to provide a method for adsorbing unsymmetrical dimethylhydrazine in an aqueous solution by using graphene oxide.

The graphene oxide is prepared by the preparation method of the graphene oxide; the method for adsorbing unsymmetrical dimethylhydrazine in an aqueous solution by utilizing graphene oxide comprises the steps of treating a carboxyl-rich graphene oxide suspension to form a carboxyl-rich graphene oxide suspension-unsymmetrical dimethylhydrazine solution; preferably, the method for adsorbing unsymmetrical dimethylhydrazine in the aqueous solution by using the graphene oxide comprises the step of treating the ferroferric oxide-loaded carboxyl-rich graphene oxide suspension to form a ferroferric oxide-loaded carboxyl-rich graphene oxide suspension-unsymmetrical dimethylhydrazine solution.

Further, the carboxyl-rich graphene oxide suspension can form a barrier film on a gas-liquid interface, so that the liquid surface area of the escape phenomenon generated by unsymmetrical dimethylhydrazine can be reduced; preferably, the loaded ferroferric oxide carboxyl-rich graphene oxide has magnetic performance, and the magnetic recoverable performance can be improved.

The fourth purpose of the invention is to provide an application of graphene oxide in absorbing unsymmetrical dimethylhydrazine in aqueous solution.

Further, unsymmetrical dimethylhydrazine in the graphene oxide adsorption aqueous solution is used as an escape inhibitor added from an external source to be applied to leakage accident treatment; preferably, the graphene oxide is loaded ferroferric oxide carboxyl-rich graphene oxide, and is used as an exogenously added escape inhibitor to improve the green and recyclable performance.

Compared with the prior art, the invention provides graphene oxide, a preparation method thereof, a method for adsorbing unsymmetrical dimethylhydrazine in an aqueous solution by using the graphene oxide, and an application of the graphene oxide, and the graphene oxide has the following beneficial effects:

1. the invention provides a graphene oxide exogenous additive structure based on a first sexual principle, wherein a carboxyl-rich graphene oxide material is prepared and synthesized by adopting an improved Hummers method, so that the structural characteristics required by an exogenous additive are met, and the environmental pollution in the material synthesis process is reduced;

2. the invention provides a method for inhibiting unsymmetrical dimethylhydrazine in an aqueous solution from escaping based on a carboxyl-rich graphene oxide material, wherein the graphene oxide with a carboxyl-rich structure is adopted to treat unsymmetrical dimethylhydrazine leakage accidents, so that the maximum escaping amount of unsymmetrical dimethylhydrazine gas is reduced, and more precious time is won for subsequent emergency rescue work;

3. aiming at the emergency treatment requirement, on the basis of not excessively damaging the escape inhibition capability of the carboxyl-rich graphene oxide, the environment-friendly and recyclable performance is increased for the escape inhibitor added from an external source by loading the ferroferric oxide magnetic material.

Drawings

Fig. 1 shows a specific graphene model structure diagram according to an embodiment of the present invention; wherein the labeling site in the labeling range is an oxygen-containing group of graphene;

FIG. 2 shows a unsymmetrical dimethylhydrazine from-CH in an embodiment of the present invention ₃ Direction near graphene oxide edge and-NH ₂ The direction is close to the edge schematic diagram of the graphene oxide; wherein a is a schematic diagram of adsorbing unsymmetrical dimethylhydrazine by using epoxy group-containing graphene oxide; b is a schematic diagram of adsorbing unsymmetrical dimethylhydrazine by using carbonyl-containing graphene oxide; c is a schematic diagram of adsorbing unsymmetrical dimethylhydrazine by using hydroxyl-containing graphene oxide; d is a schematic diagram of adsorbing unsymmetrical dimethylhydrazine by using carboxyl-containing graphene oxide;

FIG. 3 shows a charge difference diagram of absorption of unsymmetrical dimethylhydrazine molecules by graphene oxide containing hydroxyl groups and carboxyl groups according to an embodiment of the present invention; wherein a is a charge difference diagram of the hydroxyl-containing graphene oxide adsorbing unsymmetrical dimethylhydrazine molecules; b is a charge difference diagram of carboxyl-containing graphene oxide adsorbing unsymmetrical dimethylhydrazine molecules;

FIG. 4 shows a microscope image of a carboxyl-rich graphene oxide according to an embodiment of the present invention; wherein, the picture (a) is a 40 μm Scanning Tunneling Microscope (STM) picture of carboxyl-rich graphene oxide; (b) A 500nm Scanning Tunneling Microscope (STM) image of carboxyl-rich graphene oxide; (c) A 200nm transmission microscope (STM) image of carboxyl-rich graphene oxide; (d) A transmission microscope (STM) image of carboxyl-rich graphene oxide at 100 nm;

figure 5 shows XRD and Raman signatures of a carboxyl-rich graphene oxide in accordance with embodiments of the present invention; wherein (a) is XRD patterns of carboxyl-rich graphene oxide; (b) is a Raman spectra of carboxyl-rich graphene oxide;

FIG. 6 is a graph showing the analysis result of oxygen-containing functional groups of carboxyl-rich graphene oxide according to an embodiment of the present invention; wherein (a) is FT-IR patterns of carboxyl-rich graphene oxide; (b) Scanning a fine structure of carboxyl-rich graphene oxide XPS C1s with high resolution; (c) is a full spectrum scanning chart of XPS of the carboxyl-rich graphene oxide;

FIG. 7 is a diagram of a suppression effect verification test apparatus according to an embodiment of the present invention; wherein, 1, a first measuring port; 2. a second measurement port; 3. a third measurement port; 4. the entrance and the exit can be opened and closed;

FIG. 8 is a graph showing UDMH escape over time in three different modes of an embodiment of the present invention; wherein, the concentration of UDMH is 0.2g/L, 0.5g/L and 1g/L respectively;

fig. 9 shows a microscope image of a carboxyl-rich graphene oxide supported ferroferric oxide according to an embodiment of the present invention; wherein, the picture (a) is a picture of a carboxyl-rich graphene oxide supported ferroferric oxide 2 μm Scanning Tunneling Microscope (STM); (b) A 300nm Scanning Tunneling Microscope (STM) image of carboxyl-rich graphene oxide loaded ferroferric oxide; (c) A 200nm transmission microscope (STM) picture of carboxyl-rich graphene oxide loaded ferroferric oxide; (d) A transmission microscope (STM) picture of carboxyl-rich graphene oxide loaded ferroferric oxide of 100 nm;

FIG. 10 shows a time-varying graph of UDMH escape under two different treatment regimes of an embodiment of the present invention; wherein the concentration of UDMH is 0.2g/L, 0.5g/L and 1g/L respectively.

Detailed Description

For a better understanding of the present invention, specific examples will be given to further illustrate the present invention, however, it should be understood that the illustrated examples are exemplary embodiments and the present invention may be embodied in various forms without being limited to the examples set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

In the following examples, unless otherwise specified, the technical means employed are conventional means well known to those skilled in the art, and the reagents and materials of the present invention are commercially or otherwise publicly available.

The invention transversely compares unsymmetrical dimethylhydrazine treatment modes such as catalytic degradation, biological absorption and physical adsorption, and experimental results prove that the improvement mode of enhancing the water adsorption capacity by the exogenous additive in a short time in a large-reserve unsymmetrical dimethylhydrazine storage area is more realistic.

The adsorption effect of UDMH on graphene and graphene oxide with different configurations is systematically researched by relying on a Lerf-Klinowski model and utilizing a first principle. The calculation result shows that in the four oxygen-containing functional groups of epoxy, hydroxyl, carboxyl and carbonyl which may exist at the edge of graphene oxide, the epoxy and carbonyl structures are not favorable for graphene oxide to adsorb unsymmetrical dimethylhydrazine molecules, and the hydroxyl and carboxyl structures are favorable for graphene oxide to adsorb unsymmetrical dimethylhydrazine molecules, wherein the adsorption energy of the carboxyl is 0.532eV at most, and charge transfer of 0.517eV occurs. According to the calculation result of the first principle, the carboxyl-rich graphene oxide is prepared by adopting a green Hummers method, the emission of nitrogen oxides in the preparation process is reduced, and the pollution of the preparation process to the environment is reduced. The high-temperature reaction stage is added in the preparation process of the graphene oxide, so that the carboxyl functional groups at the edges of the graphene oxide are controllably prepared. The effectiveness of the carboxyl-rich graphene oxide in unsymmetrical dimethylhydrazine emergency treatment is investigated through experiments. The experimental result shows that with the increase of the unsymmetrical dimethylhydrazine leakage amount, the effect of the carboxyl-rich graphene oxide suspension in the emergency treatment is far better than that of a pure water treatment mode, for example, after the carboxyl-rich graphene oxide suspension is adopted to carry out the emergency treatment on the unsymmetrical dimethylhydrazine leakage, when the concentration of the formed solution is 0.5g/L, the maximum content of the unsymmetrical dimethylhydrazine in the gas is reduced by 75%, the early-stage remediation time is increased by 2 minutes, and convenience is provided for the follow-up leaking stoppage and rescue activities.

Meanwhile, the graphene oxide is a precursor of the reduced graphene oxide, the quality of the reduced graphene oxide determines the quality of the subsequently obtained reduced graphene oxide, and the macro and controllable preparation of the reduced graphene oxide is an important basis and prerequisite condition for large-scale preparation and application of a subsequent graphene material, so that the preparation and structure control of the graphene oxide are always important research directions in the fields of chemical oxidation-reduction methods and even graphene materials, and the graphene oxide with a carboxyl-rich structure prepared by the invention further realizes the structure control of the graphene oxide.

In addition, based on a calculation result, the escape inhibitor with green and recyclable performance is prepared in a ferroferric oxide loading mode, so that the damage of unsymmetrical dimethylhydrazine emergency treatment to ecology and environment is effectively reduced, and the economic performance of the unsymmetrical dimethylhydrazine escape inhibitor is further improved.

Example 1

In some embodiments of the present invention, a graphene oxide structure design based on a Density Functional Theory (DFT) method is provided.

Graphene Oxide (GO) is one of important graphene derivatives, and due to the coexistence of oxygen-containing functional groups on graphene oxide sheets and a graphene structure, the graphene oxide can be used as an efficient adsorption material and used for detecting low-concentration gas. Vienna ab-initio Simulation Package (VASP5.4.4) software is selected to carry out correlation calculation, and a Generalized Gradient Approximation (GGA) method is adopted to calculate the electronic exchange correlation potential energy. In terms of pseudopotential, perew-Burke-Ernzerhof (PBE) with higher accuracy is selected. Carbon (2 s) involved in the modeling ² 2p ² ) Oxygen (2 s) ² 2p ⁴ ) Nitrogen (2 s) ² 2p ³ ) And hydrogen (1 s) ¹ ) The four elements respectively consider 4, 6, 5 and 1 outermost valencesAnd (4) electrons. In the charge analysis, the charge transfer between UDMH and different graphene oxides was calculated by the Mulliken analysis method, and a correlation charge difference map was prepared by the VESTA software. Graphene consisting of 54 carbon atoms was selected as the basic structure for the simulation calculation, the specific model structure (see fig. 1). Meanwhile, the focus of the invention is on the edge part of graphene oxide, so that various oxygen-containing functional groups only exist at the edge of the model, and the oxygen-containing functional groups mainly comprise: epoxy, hydroxyl, carboxyl and carbonyl.

In the process of model design, all the structures involved are geometrically optimized without any symmetry limitation, the structure optimization calculation adopts plane wave cut-off energy of 500eV,

1 × 10 atomic force convergence criterion of ^-4 eV to ensure that the total energy of all structures converges to within 0.5 meV/atom. In the subsequent treatment, a Mulliken analysis method is adopted to calculate the charge transfer condition among different molecular structures. Graphene oxide models with different oxygen-containing functional groups and unsymmetrical dimethylhydrazine molecules are firstly placed on a side length of

And then performing structural optimization. The size of the interaction between graphene oxide with different oxygen-containing functional groups and unsymmetrical dimethylhydrazine is calculated by the following formula:

E _a ＝(E _UDMH +E _GO )-(E _UDMH+GO )

wherein E _GO And E _UDMH Total energy, E, of isolated graphene oxide and unsymmetrical dimethylhydrazine, respectively _UDNH+GO The total energy of the graphene oxide after adsorbing the unsymmetrical dimethylhydrazine is obtained. Energy of difference E _a Represents the adsorption energy, i.e. the energy absorbed or released by the graphene oxide adsorbing unsymmetrical dimethylhydrazine molecules, E _a Can be used to measure the occurrence of adsorptionThe ease of use of (c).

Example 2

In some embodiments of the present invention, an analysis of the effect of graphene oxide on the adsorption of donors or acceptors with different structures is provided.

The invention is through E _a To distinguish between different precise adsorption structures and further analyze the amount of charge transfer to define the donor or acceptor behavior of the molecule and the type of interaction force (see table 1).

Table 1: summary table of various graphene oxide structure optimization results

Note: the C-C bond refers to the bond length of the carbon linking the oxygen-containing group to an adjacent carbon

By unsymmetrical dimethylhydrazine from-CH ₃ Direction and-NH ₂ Analysis of orientation close to graphene oxide (see FIG. 2), sp of adjacent carbocycles after addition of epoxy and carbonyl groups at the graphene oxide edge ² The carbon network is destroyed and a certain local relaxation phenomenon occurs, the C-C bond adjacent to the carbon ring is removed

Respectively change to

And

the carbon ring bond angles also changed to 119 ° and 117 °. But no matter whether UDMH is from-CH ₃ Direction is also-NH ₂ When the direction is close to the edge of the graphene oxide, the graphene oxide with the structures of the epoxy group (shown in figure 2 a) and the carbonyl group (shown in figure 2 b) has very weak adsorption capacity to unsymmetrical dimethylhydrazine molecules, and even has a certain exclusion effect, so that the two structures are judged to be not beneficial to adsorbing the unsymmetrical dimethylhydrazine molecules.

When the graphene oxide edge is added with hydroxyl functional group (see figure)2c) After that, the relaxation phenomenon of the adjacent carbon ring is not significant. A C-C bond length of

Is reduced to

The carbon ring bond angle was varied to 122 °. When UDMH is from-NH ₂ When the direction is close to the edge of the graphene oxide with the hydroxyl structure, a strong adsorption effect is generated, the amount of the hydroxyl charge is increased by 0.596eV, and the adsorption energy among the hydroxyl charge and the hydroxyl charge reaches 0.307eV. But if when UDMH is from-CH ₃ When the direction is close, weak repulsion can be generated. This indicates that the hydroxyl functional group can enhance the adsorption capacity to unsymmetrical dimethylhydrazine molecules, but can be seriously affected by the orientation of the unsymmetrical dimethylhydrazine molecules.

Example 3

In some embodiments of the present invention, an adsorption effect of the graphene oxide on unsymmetrical dimethylhydrazine after a carboxyl functional group is added at an edge of the graphene oxide is provided.

When a carboxyl functional group is added to the edge of graphene oxide (see FIG. 2 d), the C-C bond length adjacent to the carbon ring is increased from

Is reduced to

The carbon ring bond angle is increased to 122 deg., the local relaxation phenomenon is not significant, and sp of the graphene surface is increased ² The carbon network is not destroyed. In this case, the charge of 0.383eV is transferred from the carbon surface to the carboxyl group, and an electron-rich region is formed near the oxygen atom, which contributes to a stronger interaction force with the adsorbate. From the calculation of bader charge, no matter unsymmetrical dimethylhydrazine is from-CH ₃ Direction is also-NH ₂ The direction is close to the edge of the graphene oxide, the charge transfer amount between the graphene oxide with the carboxyl oxygen-containing functional group and unsymmetrical dimethylhydrazine molecules is larger than that of the graphene oxide with other oxygen-containing functional groups, and reaches 0.517eV, which further shows thatThe carboxyl structure is favorable for adsorbing unsymmetrical dimethylhydrazine molecules, and the relevant charge difference graphs are shown in figure 3 (a) and figure 3 (b).

As can be seen from the calculation results (see Table 2), no matter whether UDMH is derived from-CH ₃ Direction is also-NH ₂ When the direction is close to the edge of the graphene oxide, the adsorption effect of the graphene oxide structure with the carboxyl is optimal. Combining the above calculations, the adsorption capacity to UDMH molecules can be enhanced when the graphene edge has more carboxyl groups. If the preparation of the carboxyl-rich graphene oxide is realized by chemical means, the interaction between the graphene oxide and UDMH can be greatly enhanced. Meanwhile, the research result about the oxygen-containing functional group on the surface of the graphene shows that the epoxy structure on the surface can be converted to a hydroxyl structure along with the deepening of the oxidation degree of the graphene, and the graphene oxide is also favorable for adsorbing unsymmetrical dimethylhydrazine molecules.

Table 2: summary table of calculation results of various graphene oxide absorbing UDMH

Example 4

In some embodiments of the present invention, a preparation and characteristic evaluation of carboxyl-rich graphene oxide are provided.

The experimental starting materials used include, but are not limited to (see table 3):

TABLE 3 drugs and Instrument information

The preparation steps mainly comprise: (1) Slowly mixing 1g of natural graphite powder with the fineness of 1200 meshes and 46mL of concentrated sulfuric acid in a three-neck flask and uniformly stirring; the method comprises the following steps of selecting 1200-mesh graphite powder as a precursor of a material, and providing more space for the generation of carboxyl; (2) Slowly adding 3g of potassium permanganate into the three-neck flask in turn, cooling in ice-water bath, and violently stirring by using a polytetrafluoroethylene stirring paddle at 200 rpm; (3) Adding 2mL of deionized water, and stirring until the graphite flakes are uniformly distributedDispersing in the system; (4) After the system is cooled, putting the reaction system into a constant-temperature water bath device at 40 ℃, and stirring for 90 minutes at 300 rpm; (5) After the medium temperature oxidation process at 40 ℃, slowly adding deionized water with the volume of 100mL into the reaction system, and heating to 95 ℃ to continue the reaction for 15 minutes; before the graphene oxide is subjected to high-temperature reaction, a certain amount of water is added to introduce an additional oxygen source for the reaction, so that conditions are provided for generating more carboxyl groups; (6) After the oxidation process is finished, slowly pouring the reaction liquid into a beaker which is filled with 0.2L of deionized water and has a volume of 0.5L, and then dropwise adding hydrogen peroxide (5 mL, 30%), wherein the color of the suspension is changed from brown to yellow; (7) The suspension was suction filtered and washed with hydrochloric acid over a 1; (8) And after the filter cake is dried in the air, the filter cake is taken off and torn up, and is stirred with 0.5L of deionized water overnight for dispersion, so that graphite oxide water system dispersion liquid is obtained. The use of sodium nitrate is eliminated in the preparation process, and the generation of NO caused by the use of sodium nitrate in the traditional mode is further avoided ₂ /N ₂ O ₄ The preparation method provided by the invention has the advantages that the environmental friendliness of material preparation is improved, and the oxidation degree of graphene oxide can still meet related requirements.

Microscopic analysis of the prepared carboxyl-rich graphene oxide (see fig. 4) shows that, as shown in fig. 4 (a) and 4 (b), the carboxyl-rich graphene oxide has obvious wrinkle-like STM images, and significant stacking marks are generated between material sheets due to pi-pi bonds, which are typical graphene oxide morphological structures. Statistical analysis of the sizes of the carboxyl-rich graphene oxide in the TEM measurement results, as shown in fig. 4 (c) and 4 (d), revealed that the size of the carboxyl-rich graphene oxide was mostly distributed in the range of 0 to 25 micrometers, with an average size of 11.8 micrometers, while the size of the graphene oxide prepared by the conventional Hummers method was mostly distributed in the range of 5 to 90 micrometers. The surface structure of the carboxyl-rich graphene oxide is seriously damaged by high-temperature reaction and undergoes the process of oxidative cleavage or self-decomposition by residual heptavalent manganese compounds, so that the size of the carboxyl-rich graphene oxide is smaller than that of graphene oxide prepared by a common method.

Analysis of the degree of oxidation of the prepared carboxyl-rich graphene oxide showed (see fig. 5), XRD ray diffraction pattern 5 (a) of the carboxyl-rich graphene oxide showed a characteristic (001) diffraction peak of graphene oxide, i.e., a diffraction peak at a diffraction angle 2 θ =10.9 °, corresponding to an interlayer distance of 0.81nm, and the larger interlayer distance was attributed to the strong oxidation reaction-induced oxygen-containing functional group spreading the interlayer distance of the original graphite. On the other hand, as can be seen from the Debye-Scherrer formula, the full width at half maximum of the XRD diffraction peak is generally inversely proportional to the crystallinity of the tested material. Therefore, the carboxyl-rich graphene oxide has higher oxidation degree and more oxygen-containing functional groups, so that the corresponding structure is complete, the XRD half-peak width (0.54 ℃) of the carboxyl-rich graphene oxide is smaller than that (0.42 ℃) of graphene oxide prepared by the traditional Hummers method, and the material is fully oxidized from the other side.

The raman spectrum of the carboxyl-rich graphene oxide is shown in fig. 5 (b). The raman spectrum of a typical graphene material has characteristic D peaks and G peaks, wherein the G peak is a characteristic peak of graphitized carbon in the material and corresponds to first-order scattering of graphite E2G. And the D peak corresponds to a structural defect or a partially random graphite region, is caused by A1g of K phonon, and is influenced by sp3 vibration of carbon atoms typical in the random graphite. The Raman spectrum of the carboxyl-rich graphene oxide shows a wide and combined D peak and G peak with the characteristics of the graphene oxide to a certain extent, wherein the D peak is very strong and the G peak is very wide, which indicates that the original graphite structure is quite damaged due to functionalization. Meanwhile, the intensity ratio of D/G of the D peak and the G peak is also paid much attention by researchers because the disordered structure of the material can be effectively reflected. According to the characterization results, the D/G intensity ratio of the carboxyl-rich graphene oxide is 0.886, while the D/G intensity ratio of the graphene oxide prepared by the traditional Hummers method is generally above 0.9, which indicates that the carboxyl-rich graphene oxide has more oxygen-containing functional groups.

In addition, the C1s fine structure spectrum 6 (b) results of XPS of carboxyl-rich graphene oxide also confirmed the structure, the ratio (I) of carbon oxide (C-O-C/C-OH, C = O and O-C = O) and intact carbon (C-C/C = C) in the carboxyl-rich graphene oxide _OC /I _CC ) 2.11, which is 1.2-1.5 higher than that of graphene oxide prepared by the traditional Hummers method. In addition, the suspension of carboxyl-rich graphene oxide in the previous experiment was clear yellow, which also indicates that the material had been fully oxidized.

Analysis of oxygen-containing functional groups of the carboxyl-rich graphene oxide shows (see fig. 6), and the characterization result proves that a plurality of oxygen-containing functional groups exist in the carboxyl-rich graphene oxide by researching the type and the number of the oxygen-containing functional groups of the carboxyl-rich graphene oxide through FT-IR Fourier infrared spectroscopy. For example, C-O-C (. About.1000 cm) ^-1 )，C-O(～1230cm ^-1 ) O-H bending vibration of bound water (-1620 cm) ^-1 )，C＝O(～1740-1720cm ^-1 ) O-H stretching vibration (3600-3300 cm) of carboxyl, hydroxyl and interlayer binding water ^-1 ) The specific distribution is shown in fig. 6 (a). Compared with graphene oxide prepared by the traditional Hummers method, the carboxyl-rich graphene oxide is 3600-3300cm ^-1 The vibration intensity on the frequency is stronger, and the preparation method provided by the invention proves that the carboxyl at the edge of the graphene oxide is effectively increased. The increase of carboxyl groups also leads to the increase of the interlayer spacing of the graphene oxide, which is consistent with the XRD characterization result. On the other hand, the results of the full spectrum scan by XPS of 6 (C) show that the C/O of the carboxyl group-rich graphene oxide is 2.03, which is lower than that of the C/O prepared by the general method (2.2-2.9). At the same time, the C1s fine structure spectrum of XPS is peaked and four carbon atoms are identified, namely C-C/C = C (284.8 eV), C-O-C/C-OH (286.8 eV), C = O (287.8 eV), O-C = O (289.0 eV), the contents of which reflect the functional group species on the carboxyl-rich graphene oxide. Compared with graphene oxide prepared by the traditional Hummers method, the carboxyl-rich graphene oxide has more oxygen-containing functional groups, and the hydrophilic oxygen-containing functional groups ensure good dispersibility of the carboxyl-rich graphene oxide in water.

The relevant characteristic analysis data show that the carboxyl-rich graphene oxide prepared by the method has a typical graphene oxide morphology structure and high-content carboxyl oxygen-containing functional groups, and accords with the structural characteristics of efficient adsorption of unsymmetrical dimethylhydrazine molecules by the graphene oxide designed through theoretical calculation.

Example 5

In some embodiments of the present invention, an inhibition and escape inhibition effect of carboxyl-rich graphene oxide on unsymmetrical dimethylhydrazine is provided.

The inhibition test of carboxyl-rich graphene oxide on unsymmetrical dimethylhydrazine is carried out in a transparent epoxy resin experiment box with the size of 20cm multiplied by 20cm, the experiment temperature is 25 ℃, the experiment device is a specific experiment device (shown in figure 7), the experiment device is a closed experiment box, when in measurement, a first measuring port 1, a second measuring port 2 or a third measuring port 3 are opened according to the difference of measuring sites, and any one of the 3 measuring ports can be opened or the 3 measuring ports can be opened simultaneously; and the rest of the time is closed. The openable inlet and outlet 4 is opened when unsymmetrical dimethylhydrazine and emergency treatment liquid are placed, and is closed in other time. The first measuring port 1, the second measuring port 2, the third measuring port 3 and the openable access 4 are respectively provided with a cover body, and the cover bodies are connected with the experiment device main body in an openable and closable manner through pivots. In order to prevent UDMH gas from adhering to the wall of the experiment box and influencing the detection of the concentration of poison gas, the wall of the experiment box is coated by tinfoil. The specific experimental method comprises the following steps: and (3) respectively treating pure water and carboxyl-rich graphene oxide suspension liquid with the same volume according to the leakage conditions of the UDMH with different dosages to form corresponding UDMH solutions. After the same interval time, a handheld unsymmetrical dimethylhydrazine detector UPWS-1-10T of Hangzhou Yongjie technology Limited is used for measuring, and the effectiveness of the inhibiting material is verified by extracting gas samples of different spatial sites, detecting the concentration of UDMH in the gas and comparing the concentration of UDMH in the air.

The UDMH solution in the experiment is placed in a glass beaker and is placed in the center of the bottom surface of an epoxy resin experimental box, the total volume of the solution is 100mL, and the liquid surface area is 19.625cm ² . The gas sampling is carried out by a medical 50mL injector, and a large amount of pure water is used for flushing after each sampling, so that the condition that UDMH gas is not adhered and remained in the injector is ensured. Three sampling points are distributed at the upper left part, the lower right part and the top of the experimental device, so that experimental errors caused by uneven gas diffusion can be avoided. A handheld UDMH gas detector is used for detecting the concentration of unsymmetrical dimethylhydrazine gas, the measuring range of the device is 0-1000ppm, the precision is 0.1ppm, and the requirements of experimental measurement can be met. In the aspect of the recovery of the exhaust gas,the oxalic acid solution of 10g/L is used for absorbing waste gas generated in the experiment process, and the pollution to the experiment environment is avoided.

Secondary escape volume of UDMH is C _UDMH,t ，mg/m ³ Indicating a cumulative escaped UDMH over a period of time (t). The value x is measured directly by a gas detector. In order to facilitate the comparison of the subsequent experimental results, the measurement unit needs to be converted from ppm to mg/m ³ The concrete transformation formula is as follows:

in the formula V _UDMH Volume of escaped UDMH; v _Z The total volume of the experimental instrument; n is the amount of mass of UDMH escaping; m _UDMH Molar mass of escaped UDMH; since the experimental temperature was 25 ℃, the gas molar volume was 24.5mol/L.

The three leakage doses for UDMH were selected to be 0.1g, 0.05g, 0.02g, subject to the range of the experimental space and gas detection instrument. Equal volumes of pure water and carboxyl-rich graphene oxide dispersion were then added to form 100mL solutions at concentrations of 1g/L, 0.5g/L, 0.2g/L (see FIG. 8). After equal time intervals, gas sampling is carried out from three different detection points respectively, and the unsymmetrical dimethylhydrazine concentration is detected. After the detection experiment data results are collated, trend graphs of the change of the UDMH escape amount along with time under two different processing modes can be drawn.

As can be seen from fig. 8, the unsymmetrical dimethylhydrazine in the two treatment modes has differences in key data such as initial escape time and equilibrium time. Considering that the gas-liquid interface plays an important role in the escape process, the method is researched and developed according to related experimentsThe results show that the volatilization speed of unsym-dimethylhydrazine is in positive correlation with the liquid surface area, and each increase is 20cm ² The volatilization speed of unsymmetrical dimethylhydrazine is doubled by the surface area. And a layer of barrier film can be formed on a gas-liquid interface when the carboxyl-rich graphene oxide exists in the form of suspension, so that the liquid surface area capable of generating an escape phenomenon is effectively reduced. Experimental data show that the escape speed of UDMH in the carboxyl-rich graphene oxide suspension is far lower than that of UDMH in pure water. The initial escape time is compared, and the initial escape time of the unsymmetrical dimethylhydrazine can be prolonged by using the carboxyl-rich graphene oxide dispersion liquid to treat the unsymmetrical dimethylhydrazine leakage accident. After the unsymmetrical dimethylhydrazine leakage accident is treated by pure water, the unsymmetrical dimethylhydrazine toxic gas starts to obviously escape within one minute, and the escape phenomenon can be delayed to 2 minutes after the unsymmetrical dimethylhydrazine leakage accident is treated by the carboxyl-rich graphene oxide dispersion liquid, and the rule is not easily influenced by the unsymmetrical dimethylhydrazine leakage amount; in the aspect of the balance time, the carboxyl-rich graphene oxide can inhibit unsymmetrical dimethylhydrazine toxic gas from escaping from liquid, so that the balance time can be simultaneously influenced by the inhibition effect and the unsymmetrical dimethylhydrazine leakage amount, and when the inhibition effect is obvious, the carboxyl-rich graphene oxide dispersion liquid is used for treating the unsymmetrical dimethylhydrazine leakage accident, so that the equilibrium state can be reached more quickly.

The reason for the above test results is that in pure water solution, the rate of fluid microelements rising from the inside of the solution to the surface of the liquid is fast, and the residence time at the interface is long, so that the mass transfer interface can reach the saturated concentration quickly, resulting in short initial escape time. Compared with the prior art, the carboxyl-rich graphene oxide is used for processing the unsymmetrical dimethylhydrazine leakage accident, unsymmetrical dimethylhydrazine in the fluid microelements can be continuously captured by the inhibitor in the process of rising to the liquid surface, so that the time for the mass transfer interface to reach the saturated concentration is later, and the initial escape time is delayed. In terms of maximum escape amount, whether the unsymmetrical dimethylhydrazine leakage accident is processed by pure water or carboxyl-rich graphene oxide suspension, the maximum escape amount is directly related to the number of free unsymmetrical dimethylhydrazine molecules in fluid microelements. After free unsymmetrical dimethylhydrazine molecules are adsorbed and captured by a large amount of carboxyl-rich graphene oxide, unsymmetrical dimethylhydrazine molecules which can escape from a liquid phase are greatly reduced. Compared with graphene oxide prepared by a traditional Hummer method, the carboxyl-rich graphene oxide has a better capture effect mainly due to two reasons: firstly, carboxyl tends to be distributed at the edge of graphene, graphene oxide in dispersion liquid tends to aggregate, the aggregation can affect the interlayer surface area, but the influence on the edge area is small, and the position distribution characteristic is favorable for capturing free UDMH molecules; secondly, due to acid-base neutralization reaction, the carboxyl-rich graphene oxide and the UDMH molecules have a synergistic effect of physical acting force and chemical acting force, so that the captured UDMH molecules are more stable and are not easy to escape again.

Example 6

In some embodiments of the invention, an escape inhibitor is provided that has green recyclability.

The preparation steps mainly comprise: (1) 1g of natural graphite powder (1200 mesh) was slowly mixed with 46mL of concentrated sulfuric acid in a three-necked flask and stirred uniformly. (2) Slowly adding 3g of potassium permanganate into the three-neck flask in turn, cooling in ice-water bath, and violently stirring by using a polytetrafluoroethylene stirring paddle at 200 rpm; (3) Adding 2mL of deionized water, and stirring until the graphite flakes are uniformly dispersed in the system; (4) After the system is cooled, putting the reaction system into a constant-temperature water bath device at 40 ℃, and stirring for 90 minutes at 300 rpm; (5) After the medium temperature oxidation process at 40 ℃, slowly adding deionized water with the volume of 100mL into the reaction system, and continuously reacting for 15 minutes at the high temperature of 95 ℃; (6) After the oxidation process is finished, slowly pouring the reaction liquid into a beaker which is filled with 0.2L of deionized water and has a volume of 0.5L, and then dropwise adding hydrogen peroxide (5 mL, 30%), wherein the color of the suspension is changed from brown to yellow; (7) The suspension was suction filtered and washed with hydrochloric acid over a 1; (8) After the filter cake is dried in the air, the filter cake is taken off and torn up, and is stirred with 0.5L of deionized water for overnight dispersion, so that graphene oxide water system dispersion liquid is obtained; (9) Finally, obtaining carboxyl-rich graphene oxide solid powder by adopting a freeze-drying treatment mode; (10) Taking a proper amount of carboxyl-rich graphene oxide and 50Premixing mL of glycol for later use; (11) A certain dosage of FeCl3.6H ₂ Adding O into a prepared carboxyl-rich graphene oxide and ethylene glycol solution, and carrying out ultrasonic treatment for 3h; (12) After the ultrasonic treatment is finished, adding sodium acetate, wherein the ratio of the sodium acetate to ferric ions is 8; (13) Stirring with a polytetrafluoroethylene stirring paddle at 200rpm, and heating and refluxing for 10h after uniform stirring; (14) Centrifuging, and washing with pure water and ethylene glycol for multiple times; (15) And (4) drying for 8 hours in vacuum to obtain the carboxyl-rich graphene oxide powdery solid loaded with ferroferric oxide.

The shape and size analysis of the carboxyl-rich graphene oxide-loaded ferroferric oxide shows (see fig. 9), and as can be seen from the analysis of fig. 9 (a) and 9 (b), when ferroferric oxide is loaded, the carboxyl-rich graphene oxide has a characteristic fold structure, which is very favorable for the ferroferric oxide magnetic particles to cover the surfaces of the ferroferric oxide magnetic particles, so that a plurality of spherical particles, namely Fe, can be observed through SEM images ₃ O ₄ Magnetic particles. Meanwhile, since the carbon surface is better kept to contain a large amount of oxygen-containing functional groups during the ferroferric oxide loading process, the composite material can still be peeled off in water and form a stable dispersion consisting of single-layer sheets, and the effect is also verified in TEM images 9 (c) and 9 (d). In a TEM image, it can also be observed that the carboxyl-rich graphene oxide-supported ferroferric oxide still presents a thin two-dimensional sheet microstructure with a large number of wrinkles, further indicating that after the ferroferric oxide is supported, the original carboxyl-rich graphene oxide microstructure is not greatly influenced.

In order to comparatively analyze the escape inhibition effect before and after loading, the experimental environment and equipment are consistent with those of the carboxyl-rich graphene oxide. In the measurement mode, after equal time intervals, gas sampling is respectively carried out from three different detection points, the concentration of unsymmetrical dimethylhydrazine in the gas is detected, and finally a trend graph of the change of the UDMH escape amount along with the time is drawn (see figure 10). The escape inhibition effect of two exogenous additives, namely carboxyl-rich graphene oxide loaded ferroferric oxide and carboxyl-rich graphene oxide, is compared to show that the critical data such as the balance time of unsymmetrical dimethylhydrazine in the two treatment modes are different. In the aspect of initial escape time, the escape phenomenon delaying characteristic does not change greatly, the escape phenomenon can be delayed no matter the carboxyl-rich graphene oxide loaded with ferroferric oxide or the carboxyl-rich graphene oxide before doping modification is not carried out, and the rule is not easily influenced by the leakage amount of unsymmetrical dimethylhydrazine; in the aspect of balance, due to the dual influence of the inhibiting effect and the unsymmetrical dimethylhydrazine leakage amount, under the condition that the leakage dosage is the same, the carboxyl-rich graphene oxide loaded with ferroferric oxide is similar to the carboxyl-rich graphene oxide in the balance time, but the magnetic recoverable performance is increased on the basis of the original material.

The above description is only an example of the present invention and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present application.

Claims

1. A preparation method of graphene oxide is characterized by comprising the following steps: structural design and preparation of graphene oxide;

the structural design of the graphene oxide is based on a density functional theory method;

the preparation of the graphene oxide is the preparation of carboxyl-rich graphene oxide;

the preparation method of the carboxyl-rich graphene oxide mainly comprises the steps of mixing natural graphite powder and concentrated sulfuric acid, adding potassium permanganate into an ice water bath, stirring with polytetrafluoroethylene, carrying out water treatment, carrying out high-temperature reaction on the graphene oxide, adding hydrogen peroxide, carrying out suction filtration to obtain a filter cake, and stirring and dispersing to obtain a graphite oxide water system dispersion liquid.

2. The method for preparing graphene oxide according to claim 1, wherein the graphene oxide structure design based on the density functional theory method comprises the steps of calculating by using simulation software, calculating the electron exchange related potential energy by adopting generalized gradient approximation, and performing pseudopotential analysis by using Perdex-Burke-Ernzerhof.

3. The method for preparing graphene oxide according to claim 2, wherein the step of preparing the carboxyl-rich graphene oxide comprises:

s106, after the oxidation process is finished, slowly pouring the reaction liquid into a beaker filled with 0.1-0.3L of deionized water, and then dropwise adding 3-8 mL of 30% hydrogen peroxide until the color of the suspension is changed from brown to yellow;

s107, carrying out suction filtration on the suspension, washing away residual manganese ions and potassium ions by 25 mL-75 mL of aqueous solution diluted by hydrochloric acid in a ratio of 1;

and S108, drying the filter cake, tearing off the filter cake, stirring the filter cake with 0.25-0.75L of deionized water for overnight dispersion, and obtaining graphite oxide water system dispersion liquid.

4. The preparation method of graphene oxide according to claim 3, wherein the carboxyl-rich graphene oxide is prepared by loading ferroferric oxide on carboxyl-rich graphene oxide; the preparation method comprises the following steps:

s202, slowly adding 2.0-4.0 g of potassium permanganate into a three-neck flask in a medicine spoon for several times, cooling in ice water bath, and violently stirring by using a polytetrafluoroethylene stirring paddle at 100-300 rpm;

s206, after the oxidation process is finished, slowly pouring the reaction liquid into a beaker filled with 0.1-0.3L of deionized water, and then dropwise adding 3-8 mL of 30% hydrogen peroxide until the color of the suspension is changed from brown to yellow;

s207, carrying out suction filtration on the suspension, washing away residual manganese ions and potassium ions by using 25 mL-75 mL of aqueous solution diluted by hydrochloric acid in a ratio of 1;

s208, after drying the filter cake, tearing off the filter cake, stirring the filter cake with 0.25L-0.75L of deionized water for overnight dispersion, and obtaining graphite oxide water system dispersion liquid;

s212, after the ultrasonic treatment is finished, adding sodium acetate, wherein the ratio of the sodium acetate to ferric ions is 5;

s214, carrying out centrifugal treatment, and then washing 1-3 times by using pure water and ethylene glycol;

5. Graphene oxide, which is prepared by the method for preparing graphene oxide according to any one of claims 1 to 4; the graphene oxide is carboxyl-rich graphene oxide; preferably, the carboxyl-rich graphene oxide edge is a carboxyl functional group.

6. The graphene oxide according to claim 5, wherein the carboxyl-rich graphene oxide has obvious wrinkles in STM images; preferably, the size distribution of the carboxyl-rich graphene oxide is between 0 and 25 μm.

7. The graphene oxide according to claim 6, wherein the carboxyl-rich graphene oxide is loaded ferroferric oxide carboxyl-rich graphene oxide; preferably, the loaded ferroferric oxide carboxyl-rich graphene oxide SEM image covers spherical particles in folds.

8. A method for adsorbing unsymmetrical dimethylhydrazine in an aqueous solution by using graphene oxide is characterized in that the graphene oxide is prepared according to the preparation method of the graphene oxide as claimed in any one of claims 1 to 4; the method for adsorbing unsymmetrical dimethylhydrazine in the aqueous solution by utilizing the graphene oxide comprises the steps of treating a carboxyl-rich graphene oxide suspension to form a carboxyl-rich graphene oxide suspension-unsymmetrical dimethylhydrazine solution; preferably, the method for adsorbing unsymmetrical dimethylhydrazine in the aqueous solution by using the graphene oxide comprises the step of treating the ferroferric oxide-loaded carboxyl-rich graphene oxide suspension to form a ferroferric oxide-loaded carboxyl-rich graphene oxide suspension-unsymmetrical dimethylhydrazine solution.

9. The method for absorbing unsymmetrical dimethylhydrazine in aqueous solution with graphene oxide according to claim 8, wherein the carboxyl-rich graphene oxide suspension can form a barrier film on a gas-liquid interface to reduce the liquid surface area where unsymmetrical dimethylhydrazine can generate an escape phenomenon; preferably, the loaded ferroferric oxide carboxyl-rich graphene oxide has magnetic performance, and the magnetic recoverable performance can be improved.

10. The application of utilizing graphene oxide to adsorb unsymmetrical dimethylhydrazine in an aqueous solution is characterized in that the graphene oxide is prepared according to the preparation method of the graphene oxide of any one of claims 1 to 4; the method is characterized in that unsymmetrical dimethylhydrazine in the graphene oxide adsorption aqueous solution is used as an escape inhibitor added from an external source and applied to leakage accident treatment; preferably, the graphene oxide is loaded ferroferric oxide carboxyl-rich graphene oxide, and is used as an exogenously added escape inhibitor to improve the green and recyclable performance.