Composite decontaminating agent, preparation method and application

Abstract

The invention belongs to the technical field of propellant treatment, and provides a composite decontaminant and a preparation method and application thereof in order to solve the problems that an existing neutralization decontaminant is complex in component, not high in stability and high in cost, and particularly, the composite decontaminant is prepared through the characteristic that transition metal coordination bonds are stabilized through Lewis acid metal ions and the coating effect of a surface active agent. Cu < 2 + >, Fe < 3 + >, sodium dodecyl benzene sulfonate and carboxyl-rich graphene oxide are compounded to prepare the composite decontamination agent. The composite decontaminating agent synthesized by the invention has a relatively good decontaminating effect on an unsymmetrical dimethylhydrazine propellant; the escape inhibition rate on unsymmetrical dimethylhydrazine reaches 35.1 percent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of propellant treatment, and particularly relates to a composite decontamination agent, a preparation method and application. BACKGROUND

[0002] Liquid propellant is the primary power source in the field of aerospace and aviation. It can not only precisely control the size and direction of thrust, but also help spacecraft complete complex space tasks. It also lays the foundation for human exploration of the universe due to its unique performance advantages. Countries have invested a large amount of funds and scientific research power to improve its performance and safety.

[0003] Traditional liquid propellants include red fuming nitric acid, unsymmetric dimethylhydrazine (UDMH), tetranitrogen dioxide, and mixed hydrazine. UDMH, as a high-energy liquid fuel, has always played a crucial role in space and military launch missions. UDMH has the following three core advantages: first, it has strong reducing properties. It can self-ignite without pretreatment as long as it is in contact with an oxidizing agent. This can greatly simplify the structure of the engine device, significantly shorten the launch preparation time, and improve the reliability performance. Second, it has high specific impulse. When used in combination with tetranitrogen dioxide, the specific impulse can reach about 2960 seconds, enhancing the reliability of combat tasks and providing the required war time. Third, it has stable storage properties. It does not need to be stored at low temperatures and can be stored for a long time at room temperature, providing the ability to quickly mobilize liquid missile weapons into military operations. Time is the key factor for victory. For the missile launch link of the army, having the above advantages can help us gain more initiative in complex battlefield environments and further improve strategic balance capabilities.

[0004] However, UDMH, as a highly toxic substance with a toxicity level of III, is clearly regulated in GJB16223 "Hygienic Standard for UDMH in Workshop Air". The concentration of UDMH gas in the air must be less than 0.5 mg / m 3, personnel long-term environment more than this value or long-term exposure to excessive concentrations of UDMH gas, may appear dizziness, nausea, vomiting and other symptoms, severe coma and even death, acute injury and long-term health hazards to human health. In addition, the explosion limit of unsymmetrical dimethylhydrazine is 2.5-78.5%, and the vapor pressure is high, once leaked, it will evaporate rapidly, and will spread rapidly in the air in a short time, if the unsymmetrical dimethylhydrazine vapor reaches a certain concentration, it will have a high probability of explosion. Moreover, as a strong reducing agent, if it is leaked and contacted with oxidizing agent, it may cause violent reaction, generate a large amount of heat and gas, and aggravate the severity of the accident. In general, the physical and chemical properties of unsymmetrical dimethylhydrazine make it highly dangerous, and these properties determine that the handling of unsymmetrical dimethylhydrazine leakage accident needs special caution, and effective protection and emergency measures must be taken to reduce the harm to personnel and environment.

[0005] For unsymmetrical dimethylhydrazine leakage problem, the common emergency disposal methods mainly have the following three types: leakage source plugging method, emergency disposal adsorption method, water spraying method. For some low pressure, small leakage amount and irregular leakage site or in flammable and explosive environment, leakage source plugging method can be considered. Although eliminating the leakage hazard from the source conforms to the concept of intrinsic safety, in actual operation, plugging the leakage source is complex and dangerous, and the technical difficulty is great, which requires professional equipment and exquisite technology. In addition, unsymmetrical dimethylhydrazine is flammable and explosive and highly toxic, which is extremely dangerous to the life and health of rescue personnel. According to incomplete statistics, in the past emergency disposal of dangerous chemical leakage accidents, the number of successful plugging accidents is less than half of the total number, and often accompanied by rescue personnel casualties. Therefore, the leakage source plugging method is limited and has many shortcomings. At present, the most commonly used method for emergency disposal of unsymmetrical dimethylhydrazine is still adsorption method. In other existing researches, most of them are mainly for absorbing and adsorbing unsymmetrical dimethylhydrazine wastewater and waste gas. The water spraying system for emergency disposal of unsymmetrical dimethylhydrazine leakage is still not perfect, and there are the following two challenges: first, the water demand is large; after the accident of Atlas II, many units adopted emergency fire water treatment scheme, that is, thousands of tons of water near the storage site to carry out emergency disposal and decontamination treatment. However, if a large amount of leakage occurs, and in the case of dynamic diffusion of unsymmetrical dimethylhydrazine gas volatilization, thousands of tons of water is completely insufficient. Second, after water spraying treatment, although the concentration of unsymmetrical dimethylhydrazine in gas phase can be quickly reduced, according to the actual situation of Atlas II intercontinental missile, unsymmetrical dimethylhydrazine will still escape from water again, forming a new dangerous source and pollution source, causing secondary disasters. At the same time, it endangers the life safety of workers and causes damage to surrounding equipment. According to the above analysis, although water spraying technology has the advantage of rapid reaction, the shortcomings of this technology cannot be ignored.

[0006] On the basis of the above-mentioned existing emergency disposal technology, Cheng Yongxi etc. proposed a neutralization decontamination solution with citric acid, potassium sorbate, calcium chloride, calcium nitrate, sodium nitrate, acetic acid, water and other reagents, which is mainly obtained by fully mixing the solution through stirring. This kind of neutralization decontamination agent disposal method has the following four shortcomings:

[0007] 1. The composition of the decontamination agent is complex, and after the treatment of unsymmetrical dimethylhydrazine, the waste liquid cannot be directly discharged, and secondary treatment work must be carried out, which undoubtedly greatly increases the treatment cost and brings great pressure to the related work from the economic aspect.

[0008] 2. The formula proportion of the decontamination agent is extremely critical, and the operation process also has strict specification requirements. If the formula proportion deviates in actual use, or the operation does not follow the standard process, it will seriously affect the absorption effect of unsymmetrical dimethylhydrazine, making it difficult to achieve the goal of removing unsymmetrical dimethylhydrazine pollution, and cannot effectively guarantee the environmental safety

[0009] 3. The stability of the decontamination agent is poor, and it is easily affected by various factors such as temperature, light, storage time, etc. during storage and use, resulting in changes in its performance, thereby reducing the treatment capacity of unsymmetrical dimethylhydrazine and affecting the reliability of the treatment effect.

[0010] 4. The cost price of the decontamination agent is high, which not only reflects the high cost of raw material procurement, but also includes the fees of production, transportation and other links. The high cost limits its large-scale application, and to some extent hinders the widespread development of emergency disposal work.

[0011] In view of the above problems existing in the current decontamination agent, it is more necessary to develop a liquid adsorption material with low cost and good economy for large-area spraying treatment, so as to have sufficient adsorption capacity and decontamination capacity, treat all uncertain leakage points in a large area, reduce the process of close-range disposal of personnel, and achieve efficient, comprehensive and safe precise control of the escape and diffusion rate of unsymmetrical dimethylhydrazine. SUMMARY

[0012] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a composite decontamination agent, a preparation method and an application.

[0013] An object of the present application is to provide a composite decontamination agent made from the following volume parts of raw materials:

[0014] Carboxyl-rich graphene oxide solution 4 parts, copper nitrate solution 1 part, iron nitrate solution 1 part and surfactant solution 1 part.

[0015] Preferably, the concentration of the carboxyl-rich graphene oxide solution is 17.8 g / L, the concentration of the copper nitrate solution is 90 mmol / L, the concentration of the iron nitrate solution is 10-30 mmol / L, and the concentration of the surfactant solution is 0.5 g / L.

[0016] Preferably, the surfactant solution is a sodium dodecyl benzene sulfonate solution.

[0017] A second object of the present application is to provide a preparation method of the composite decontamination agent described above, comprising the following steps:

[0018] S1, preparation of a carboxyl-rich graphene oxide solution;

[0019] S2, respectively taking 4 parts of the carboxyl-rich graphene oxide solution, 1 part of the copper nitrate solution, 1 part of the iron nitrate solution, and 1 part of the surfactant solution by volume fraction, for standby;

[0020] S3, mixing the solutions taken in step 2 uniformly to obtain the composite decontamination agent.

[0021] Preferably, step S1 comprises the following steps:

[0022] S11, dissolving graphene oxide powder in water and ultrasonic dispersion for 1 h to obtain a graphene oxide dispersion;

[0023] S12, adding chloroacetic acid into the graphene oxide dispersion, stirring for 3 h, and after the reaction is completed, performing centrifugation, water washing, and freeze-drying treatment to obtain carboxyl-rich graphene oxide powder;

[0024] S13, configuring the carboxyl-rich graphene oxide powder into a carboxyl-rich graphene oxide solution.

[0025] A third object of the present application is to provide an application of the composite decontamination agent described above in adsorption of unsymmetrical dimethylhydrazine propellant.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] (1) The composite decontamination agent provided by the present application provides efficient reactant enrichment for the decontamination reaction through the chemical adsorption of carboxyl-rich graphene oxide, the Lewis acid-base reaction of metal ions accelerates the decomposition of UDMH, and the coating effect of the surfactant optimizes the mass transfer process and reaction environment of the reaction system; under the synergistic effect of the three, the composite decontamination agent compounded by carboxyl-rich graphene oxide, metal ions, and surfactants can maximize the advantages of each component, thereby achieving the best decontamination effect;

[0028] (2) The composite decontamination agent provided by the application not only significantly reduces the escape rate of UDMH in the gas phase, but also effectively reduces the gas phase concentration in the closed system, providing an efficient and reliable solution for the decontamination of unsymmetrical dimethylhydrazine;

[0029] (3) The application can enhance electron transfer, optimize coordination structure and regulate reaction environment through the synergistic effect of Fe 3+ and Cu 2+ , thereby significantly improving the decontamination effect on UDMH. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a preparation process diagram of graphene oxide; wherein, (a) is a state after low-temperature reaction; (b) is a state after high-temperature reaction; (c) is a processing diagram before centrifugation; (d) is a processing diagram after centrifugation;

[0031] Figure 2 is a processing diagram of carboxyl-rich graphene oxide before and after centrifugation in the preparation process of the carboxyl-rich graphene oxide; wherein, (a) is a processing diagram before centrifugation; (b) is a processing diagram after centrifugation;

[0032] Figure 3 is a scanning electron microscope and transmission electron microscope characterization diagram of graphene oxide; wherein, (a) is a SEM diagram; (b) is a SEM diagram at a magnification; (c) is a TEM diagram; (d) is a TEM diagram at a magnification;

[0033] Figure 4 is a scanning electron microscope and transmission electron microscope characterization diagram of carboxyl-rich graphene oxide; wherein, (a) is a SEM diagram; (b) is a SEM diagram at a magnification; (c) is a TEM diagram; (d) is a TEM diagram at a magnification;

[0034] Figure 5 is a comparison diagram of X-ray diffraction of graphene oxide and carboxyl-rich graphene oxide;

[0035] Figure 6 is a comparison diagram of Raman spectrum of graphene oxide and carboxyl-rich graphene oxide;

[0036] Figure 7 is a comparison diagram of Fourier infrared of graphene oxide and carboxyl-rich graphene oxide;

[0037] Figure 8 is an X-ray electron spectroscopy diagram of graphene oxide and carboxyl-rich graphene oxide;

[0038] Figure 9 is a C1s X-ray electron spectroscopy diagram of graphene oxide and carboxyl-rich graphene oxide; wherein, (a) is a C1s X-ray electron spectroscopy diagram of graphene oxide; (b) is a C1s X-ray electron spectroscopy diagram of carboxyl-rich graphene oxide;

[0039] Figure 10 The decontamination effect comparison chart of graphene oxide and carboxyl-rich graphene oxide;

[0040] Figure 11 The decontamination effect comparison chart of carboxyl-rich graphene oxide on UDMH under different adding amounts;

[0041] Figure 12 The effect comparison chart of Cu 2+ concentration on the decontamination effect of UDMH;

[0042] Figure 13 The effect comparison chart of Fe 3+ concentration on the decontamination effect of UDMH;

[0043] Figure 14 The effect comparison chart of Fe 3+ and Cu 2+ on the escape inhibition effect of UDMH;

[0044] Figure 15 The time escape inhibition effect chart of sodium dodecyl benzene sulfonate concentration on the gas phase concentration of UDMH; wherein, (a) is the escape inhibition effect comparison bar chart; (b) is the escape inhibition effect comparison line chart;

[0045] Figure 16 The synergistic action mechanism chart of carboxyl-rich graphene oxide and metal ions, surfactant on the decontamination of UDMH. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below. Figures 1 to 16 The technical solutions in the embodiments of the present application will be clearly and completely described below.

[0047] Embodiment 1

[0048] The composite decontamination agent provided by the embodiments of the present application is made of the following raw materials in volume fraction:

[0049] The carboxyl-rich graphene oxide solution is 4 parts, the copper nitrate solution is 1 part, the iron nitrate solution is 1 part, and the surfactant solution is 1 part.

[0050] In the embodiments of the present application, the concentration of the carboxyl-rich graphene oxide solution is 90 mmol / L, the concentration of the copper nitrate solution is 90 mmol / L, the concentration of the iron nitrate solution is 10 mmol / L, and the concentration of the surfactant solution is 0.5 g / L.

[0051] In the embodiment of the present application, the surfactant solution is a sodium dodecyl benzene sulfonate solution.

[0052] The embodiment of the present application also provides a preparation method of the composite decontamination agent.

[0053] S1, preparation of the carboxyl-rich graphene oxide solution, specifically comprising the following steps:

[0054] S11, dissolving graphene oxide powder in water and ultrasonic dispersion for 1h to obtain a graphene oxide dispersion;

[0055] S12, adding chloroacetic acid into the graphene oxide dispersion, stirring for 3h, and after the reaction is completed, performing centrifugal, water washing and freeze-drying treatment to obtain carboxyl-rich graphene oxide powder;

[0056] S13, configuring the carboxyl-rich graphene oxide powder into a carboxyl-rich graphene oxide solution.

[0057] S2, respectively taking 4 parts of the carboxyl-rich graphene oxide solution, 1 part of the copper nitrate solution, 1 part of the iron nitrate solution and 1 part of the surfactant solution by volume fraction, and reserving;

[0058] S3, mixing the solutions taken in step 2 uniformly to obtain the composite decontamination agent.

[0059] Example 2

[0060] The embodiment of the present application provides a composite decontamination agent, the composition and the preparation method of the composite decontamination agent are the same as those of the composite decontamination agent in Example 1, and the only difference is that the concentration of the iron nitrate solution is 30mmol / L.

[0061] The research process of the composite decontamination agent provided by the present application is described in detail below.

[0062] I. Graphene oxide carboxylation modification and characterization research

[0063] 1. Preparation of graphene oxide and carboxyl-rich graphene oxide

[0064] 1.1. Preparation of graphene oxide by modified Hummers method

[0065] The modified Hummers method can provide more hydrophilic graphene oxide materials in the preparation process of graphene oxide, improve the efficiency of the oxidation process, and will not produce toxic gas, and can also effectively realize the temperature control. This improved graphene oxide synthesis method has important significance for the large-scale production of graphene oxide and the construction of equipment composed of subsequent chemical conversion graphene.

[0066] The preparation of graphene oxide (GO) is mainly divided into four parts: low temperature reaction, medium temperature reaction, high temperature reaction and washing reaction. The low temperature reaction is to fully intercalate, the medium temperature reaction is to fully oxidize, the high temperature reaction is to completely hydrolyze, and then the product is washed to neutral to obtain graphene oxide dispersed in water. As shown in Figure 1 , the specific preparation process is as follows:

[0067] (1) The low temperature reaction mainly occurs in the intercalation between the graphite layers. 70 mL of concentrated sulfuric acid is added to a beaker, and 3 g of graphite powder, 1.5 g of NaNO3 and 9 g of KMnO4 are added under constant stirring in an ice bath at 4℃. It is worth noting that a large amount of heat will be released after adding potassium permanganate, so it should be added in small amounts and stirred quickly, and the temperature should be kept below 4℃.

[0068] (2) The medium temperature reaction mainly occurs in the intercalation compound between sulfuric acid and graphite, which makes the graphite fully oxidized. The mixed solution will be brown. The specific operation is to transfer the beaker to a constant temperature water bath at 35℃, and magnetically stir for 2h to fully oxidize.

[0069] (3) The high temperature reaction process mainly occurs in the hydrolysis reaction of the intercalation compound. 150 mL of deionized water is added to the original beaker, and then transferred to a constant temperature water bath at 95℃, and magnetically stirred for 15 min. After completion, 500 mL of deionized water at room temperature is added to terminate the reaction, and finally 20 mL of H2O2 solution (30wt%) is slowly added.

[0070] (4) The washing process is to remove the excess acid and by-products by centrifugation at a low speed of 2500 r / min. During the washing process, the OH － and H + in the interlayer of the oxidized graphite combine to form water molecules, so the product gradually changes from golden yellow to black.

[0071] After the preparation of graphene oxide material, a small amount of graphene oxide solution is taken in a dry petri dish for weighing, and then the solid-liquid mixture is separated by suction filtration and drying to remove residual water. By comparing the mass change before and after, the concentration of the prepared graphene oxide is 18 mg / mL.

[0072] The subsequent experiments in the preparation of the present application do not perform drying treatment, because any degree of drying will trigger the dehydration reaction of graphene oxide, which will cross-link adjacent sheets and reduce their processing performance in water.

[0073] 1.2, using S N 1 nucleophilic substitution reaction method for preparing carboxyl-rich graphene oxide

[0074] Graphene oxide in its aqueous dispersion, due to the presence of water molecules, is not prone to reaction, and the water molecules effectively passivate its functional groups. The preparation of carboxyl-rich graphene oxide is based on the preparation of graphene oxide and further modification. First, the graphene oxide solution is placed in an ultrasonic cleaner, and the graphene oxide is fully dispersed under a certain ultrasonic intensity. Then, the active sites on the edges of the graphene oxide layers are used to introduce a large number of high-activity carboxyl functional groups on the edges of the graphene oxide through S N 1. Reaction mechanism, the polar functional groups of chloroacetic acid and graphene oxide undergo nucleophilic substitution reaction, thereby introducing a large number of high-activity carboxyl functional groups on the edges of graphene oxide. The specific preparation operation process is as follows:

[0075] (1) 500 mL of deionized water is added to a 1000 mL beaker, and then 0.5 g of GO powder is added, which is fully dispersed by ultrasonic instrument for 1 h to form a uniform GO dispersion liquid.

[0076] (2) 7.5 g of chloroacetic acid is weighed and placed in a beaker, and the internal nucleophilic reaction is fully carried out under ultrasonic stirring for 3 h.

[0077] (3) After the reaction is completed, the product is centrifuged and washed with deionized water to remove residual impurities, and finally freeze-dried to obtain carboxyl-rich graphene oxide (CGO), as shown in Figure 2 .

[0078] Although ordinary graphene oxide contains hydroxyl, epoxy, carboxyl and other oxygen-containing functional groups on the surface, the content of carboxyl is relatively limited. Through this modification, the dispersion of graphene oxide is better, the existence of a large number of polar carboxyl groups enhances the solubility of graphene oxide material in polar solvents, and reduces the agglomeration phenomenon caused by van der Waals force and π-π stacking effect between the layers. In terms of reactivity, the high-activity carboxyl functional group is more prone to dehydration condensation reaction with compounds containing amino, hydroxyl and other groups, providing more sites for subsequent covalent functional modification, and more efficiently introducing functional molecules or polymers, expanding its application in composite material preparation.

[0079] 2. Characterization of graphene oxide and carboxyl-rich graphene oxide

[0080] 2.1. Scanning electron microscopy and transmission electron microscopy characterization

[0081] After 48 h of vacuum drying machine treatment, graphene oxide solid powder material is obtained, and the SEM and TEM images of the graphene oxide solid powder material and the carboxyl-rich graphene oxide powder are shown in Figure 3 and Figure 4 , respectively, by Figure 3 and Figure 4It can be seen that the prepared graphene oxide and carboxyl-rich graphene oxide material are both two-dimensional sheet materials, and the surface is uneven, and there are some rough sheet materials, which show overlapping, crinkled folding structure morphology, and not all single layer structure. Such morphology can greatly improve the specific surface area, increase the adsorption sites, and improve the adsorption capacity. In addition, under the observation of the transmission electron microscope, the thickness reaches the nanometer level, the sheet layer has good transparency, the irregular sheet boundary can be clearly and obviously seen, has a typical "silk-like" wrinkle, and there are no obvious agglomerated particles on the structure surface, which proves that the graphite powder has been successfully exfoliated into graphene oxide, and can be stably dispersed in the solution. After GO is modified to synthesize CGO, the wrinkles increase, which may be because the carboxyl groups are grafted on the surface of the graphene oxide, so that more wrinkles are generated on the surface of the material.

[0082] 2.2, X-ray diffraction characterization

[0083] By Figure 5 It can be seen that obvious peaks can be observed for GO and CGO, indicating that both materials are crystalline and are a type of shaped sample. The specific analysis is as follows:

[0084] First, there are obvious sharp reflection peaks, indicating that the materials are crystalline and are shaped samples. Second, the angles corresponding to the highest peaks are different, 2θ of graphene oxide is 12.30°, and 2θ of carboxyl-rich graphene oxide is 10.99°. It is known that under the condition of Cu Kα radiation as the X-ray source, n=1, according to the Bragg equation, the interlayer spacing of graphene oxide is calculated as The interlayer spacing of carboxyl-rich graphene oxide is In addition, the characteristic diffraction peak of graphite 2θ=26° appears, and the interlayer spacing is The above results show that the prepared graphene oxide and carboxyl-rich graphene oxide are completely oxidized, and the crystal spacing of GO and CGO is more significantly expanded than that of graphite crystal spacing. This indicates that a large number of oxygen-containing functional groups are successfully embedded between the layers. It is also possible that the introduction of carboxyl groups (-COOH) intensifies the interlayer repulsion, resulting in a more loose layered structure.

[0085] In summary, the XRD data shows that the GO and CGO are successfully prepared, the interlayer spacing and electronic structure of the material are significantly changed by the embedding of oxygen-containing functional groups, and part of the crystalline properties is also retained.

[0086] 2.3, Raman spectroscopy characterization

[0087] The order of material structure, defect density, chemical composition and micro information of external environment response can be effectively analyzed by the peak position, peak shape and intensity ratio of Raman spectrum, and the results are shown in Figure 6 The specific analysis process is as follows:

[0088] (1) In the Raman spectrum, there are 1572cm -1 G peak and 1351cm -1 D peak, and the peak position of graphene oxide and carboxyl-rich graphene oxide does not change significantly, which shows that GO and CGO both have typical graphene material characteristics. Among them, the D peak reflects a part of irregular graphite area or structural defect area, which is derived from the symmetric K point phonon breathing mode and the breathing vibration of sp 3 hybrid carbon; the G peak is the characteristic peak of graphitized carbon, which shows the carbonization degree of the material, and corresponds to the first-order scattering of graphite E2g, which reflects the in-plane stretching vibration of sp 2 hybrid carbon atoms and characterizes the crystallinity of the material.

[0089] (2) According to the peak value in Figure 6 , further calculation can be obtained that the ratio of the peak height of graphene oxide D peak and G peak is 0.93, and the ratio of the two peaks of carboxyl-rich graphene oxide is 0.96. This change shows that a large number of oxygen-containing functional groups are introduced in the oxidation process, which destroys the sp 2 network and forms sp 3 hybrid defects, resulting in the enhancement of D peak. Secondly, it is possible to increase the fracture or edge defects of the layer.

[0090] As mentioned above, carboxyl-rich graphene oxide has more oxygen-containing functional groups and surface defects, which can effectively enhance the polar interaction of functional groups, increase the adsorption active site, reduce the reaction activation energy, and improve the capture ability of gas or small molecules. At the same time, the dispersibility of the material in water is increased, and the interface compatibility is optimized.

[0091] 2.4, Fourier infrared characterization

[0092] FT-IR explores the functional group content of the prepared graphene oxide and carboxyl-rich graphene oxide and the change of functional group after carboxylation, and the results are shown in Figure 7 The analysis process is as follows:

[0093] (1) In the spectrum of graphene oxide, graphene oxide has-OH absorption peak at 3408cm -1 , C=O and-COOH stretching vibration absorption peak at 1728cm -1 , C=C aromatic stretching vibration absorption peak at 1606cm -1 , and C=C aromatic stretching vibration absorption peak at 1215cm -1The C=O vibration peak at the presence of epoxy group. This shows that: oxygen-containing functional groups have been successfully grafted to the surface and edge of graphite, so that the oxidized graphite has high hydrophilicity and dispersibility in water.

[0094] (2) In the graph of carboxyl-rich graphene oxide, the absorption peak of -OH at 3363 cm -1 , the stretching vibration absorption peak of -COOH at 1739 cm -1 , the aromatic stretching vibration absorption peak of C=C at 1622 cm -1 , the C=O absorption peak at 1300-1211 cm -1 , the C-O-C vibration peak of epoxy group at 792-709 cm -1 , and the stretching vibration peak of C-O of alkoxy at 952 cm -1 , the vibration peak of C-Cl at 594 cm -1 .

[0095] (3) By comparison, it can be found that the O-H absorption peak of carboxyl-rich graphene oxide is weakened, and the C=O absorption is enhanced, which shows that the carboxylation of GO is successfully realized. In addition, it is found that there is a strong and wide peak at about 952 cm -1 , and the C-O stretching vibration is obviously enhanced. And the prepared carboxylated graphene oxide sample introduces new functional groups C-O-C and C-Cl.

[0096] In summary, the use of modified Hummers method to prepare graphene oxide can make the number of oxygen-containing functional groups on the carboxylated graphene oxide more, so that the hydrophilic oxygen-containing functional groups can ensure that the carboxyl-rich graphene oxide has good dispersibility.

[0097] 2.5, X-ray electron spectroscopy characterization

[0098] Through the characterization analysis of XPS, the element composition, chemical state and chemical interaction of the prepared graphene oxide and carboxyl-rich graphene oxide materials can be analyzed, and the results are shown in Figure 8 , and the analysis process is as follows:

[0099] (1) In the photoelectric emission process, energy transfer from one electron to another will cause the appearance of lines and peaks, and by matching the binding energy of different peaks with known standard values, the elements and content on the surface can be obtained. The total spectrum of graphene oxide and carboxyl-rich graphene oxide shows that the peak at O1s of carboxyl-rich graphene oxide is significantly higher than that of graphene oxide, and the peak at C1s is almost the same. It is proved that the content of carboxyl and other oxygen-containing functional groups in carboxyl-rich graphene oxide material is increased, which makes the total oxygen content in the material rise. In addition, two small peaks appear on the left side of the two peaks, which is caused by the loss of electrons of C1s and O1s.

[0100] (2) The results of the calculation of the carbon and oxygen atom content of carboxyl-rich graphene oxide and graphene oxide are shown in Table 1 below.

[0101] Table 1 Carbon and oxygen atom content of carboxyl-rich graphene oxide and graphene oxide

[0102]

[0103] From the results in Table 1, it can be seen that the oxygen content in CGO is as high as 4.32% higher than that in GO, which shows that the carboxyl-rich modification effect on the surface of graphene oxide is significant.

[0104] (3) To further analyze and judge the functional group content of graphene oxide and carboxyl-rich graphene oxide, the C1s energy signal in the XPS of the two materials is fitted respectively, and the fitting results are shown in Figure 9 , and it can be seen from Figure 9 that in the C1s spectrum of GO and CGO, there are five characteristic peaks, among which 282.52eV is C=C(sp2) peak, 283.55eV is C-C(sp3) peak, 284.79eV is C-O / C-O-C peak, 285.83eV is C=O peak and 286.51eV is O-C=O peak. These characteristic peaks can prove that GO and CGO are rich in different oxygen-containing functional groups, which significantly improves the surface water absorption of the material. In addition, the ratio of oxidized carbon (C-O-C / C-OH, O-C=O and C=O) to complete carbon (C-C / C=C) in carboxyl-rich graphene oxide (I OC / I CC ) is 1.86, which is 1.2-1.5 times higher than that of graphene oxide prepared by traditional Hummers method.

[0105] 3. Comparison of washing performance of graphene oxide and carboxyl-rich graphene oxide

[0106] 3.1. GO and CGO washing experiment

[0107] The single factor comparison method is used to explore the decontamination performance of graphene oxide material and carboxyl group-rich graphene oxide. In the experiment, 500 mL single-neck round-bottom ball bottle is used as the main device. First, 630 μL of dimethylhydrazine yellow liquid is taken by a microsyringe and injected into 100 mL of water. At this time, the concentration of dimethylhydrazine solution is 0.5 g / L in theoretical calculation. After stirring for 10 min and standing for 1 h, the gas-liquid two-phase equilibrium state in the bottle is reached, and then the data of the first hour is recorded. When exploring the decontamination effect of GO and CGO, the amount of GO and CGO added is changed, and the same method is used. After stirring for 10 min and standing for 1 h, the gas concentration is detected after reaching equilibrium. Then, the quantitative determination and calculation of the escape inhibition rate of various decontaminants on dimethylhydrazine gas are carried out.

[0108] In addition, the present application mainly explores the emergency disposal and decontamination effect of dimethylhydrazine, so the values tested and recorded in the gas detector are the initial maximum concentration after reaching the gas-liquid two-phase equilibrium. After a series of experiments, the experimental data are recorded.

[0109] The escape inhibition rate of various decontaminants on dimethylhydrazine gas is calculated according to the following formula:

[0110]

[0111] In the formula, N is the gas escape inhibition rate, C is the initial dimethylhydrazine concentration in the bottle, and C1 is the dimethylhydrazine concentration after adding the decontaminant.

[0112] As shown in Figure 10 , in the six groups of experiments, 1 mL to 6 mL of GO and CGO are added, and then the six groups of escape inhibition rates of GO are calculated as -53.9%, -79.2%, -61.2%, -37.1%, -43.3%, and -16.9%, with an average inhibition rate of -48.6%. The six groups of escape inhibition rates of CGO are 11.2%, 10.8%, 12.9%, 45.3%, 12.4%, and 23.1%, with an average inhibition rate of 19.23%. It can be seen that the gas escape inhibition rate after adding GO is always negative, and there is basically no inhibition effect on dimethylhydrazine, but the gas escape inhibition rate after adding CGO is positive, and the highest value in the six groups can reach 45.3%. Through the comparison of the above results, it can be seen that carboxyl group-rich graphene oxide has a significant inhibition effect on dimethylhydrazine, and through Figure 11 It can be seen that when the amount of CGO added is 4 mL, the best decontamination effect is obtained, which can ensure that the amount of decontaminant reaches the optimization of cost and efficiency.

[0113] 3.2, GO and CGO decontamination effect analysis

[0114] Through further thinking, the following reasons are analyzed to explain the CGO decontamination effect is better than GO, specific analysis as follows:

[0115] (1) The surface functional groups of graphene oxide are mainly used by physical adsorption method, through the hydrogen bond and van der Waals force between carbonyl, epoxy and carboxyl groups and the interaction with UDMH, so the adsorption capacity is limited. But the carboxyl functional groups in carboxyl-rich graphene have good advantage. As we all know, the pKa of carboxyl group is about 4-5, which can be ionized to-COO － and H + in solution, enhancing the negative charge of the surface, while the UDMH with amino group on the surface has a protonated positively charged group-NH-NH3 + , both of which are enhanced by electrostatic attraction.

[0116] (2) The carboxyl groups on the surface of carboxyl-rich graphene oxide can effectively improve the adsorption efficiency and chemical bonding strength by forming coordination bonds with the amino groups in the polar groups of UDMH.

[0117] (3) The carboxyl groups on the surface of carboxyl-rich graphene oxide can effectively improve the adsorption efficiency and chemical bonding strength by forming coordination bonds with the amino groups in the polar groups of UDMH. + (3) The carboxyl groups on the surface of carboxyl-rich graphene oxide can release H

[0118] (4) GO is prone to aggregation due to uneven distribution of oxygen-containing groups, and the effective specific surface area is reduced. However, the introduction of carboxylic acid groups improves the dispersibility of CGO in water, avoids agglomeration, and thus exposes more active sites. In addition, the functionalization process of CGO may increase the microporous or mesoporous structure of the material surface, which can effectively enhance the physical entrapment capacity of UDMH.

[0119] II. Preparation of composite decontamination agent based on carboxyl-rich graphene oxide

[0120] 1. Preliminary exploration of low concentration of metal ion complex

[0121] In most cases, coordination reactions, redox reactions, and complex decomposition reactions involving metal ions are accompanied by heat release. For example, in coordination reactions, metal ions form coordinate bonds with ligands to release energy and release heat; in redox reactions, the energy released by the formation of new bonds is greater than the energy absorbed by the breaking of old bonds, resulting in heat release; in complex decomposition reactions, when precipitates or weak electrolytes are generated, the formation of ionic bonds releases lattice energy and releases heat; when gaseous metal ions dissolve in water to form hydrated ions, they also release a lot of heat.

[0122] Therefore, in order to prevent the reaction from being blocked due to excessive reaction heat release during the experiment or to prevent the existence of safety hazards in the closed container experimental system, the application prepares a low-concentration Lewis acid solution and a surfactant (sodium dodecyl benzene sulfonate) solution to evaluate the exothermic reaction before the experiment. It is found through observation that the experimental exothermic reaction is not obvious, and the temperature fluctuation under the control of the water bath pot is not more than 3 DEG C, which indicates that the two solutions can be compounded in a large dose.

[0123] Further experimental operation is carried out, and two selected ions (Fe 2+ , Cu 3+ ) and surfactants (sodium dodecyl benzene sulfonate) are preliminarily explored. The gas phase concentration changes of unsymmetrical dimethylhydrazine before and after the addition of the decontaminating agent are shown in Table 2.

[0124] Table 2 Preliminary exploration results of the compounding effect

[0125]

[0126] It is found through the results in Table 2 that the decontaminating agent of this type of compounding has an escape inhibition effect on UDMH.

[0127] 2, Research on the decontamination performance of CGO and metal ion compounding

[0128] In order to further improve the decontamination performance of the decontaminating agent, the application carries out exploration on the compounding of carboxyl-rich graphene oxide and Lewis acid, wherein the selected Lewis acid solution is Cu(NO3)2·3H2O and Fe(NO3)3·9H2O two kinds of metal ion solutions.

[0129] The experiment of the application adopts single factor comparison method, ensures that other variables are unchanged, changes the concentration of Lewis acid solution added, records, data and explores the change of the gas concentration value of unsymmetrical dimethylhydrazine. The specific experimental operation is divided into ten groups, first, 10mmol / L, 30mmol / L, 50mmol / L, 70mmol / L, 90mmol / L Cu(NO3)2·3H2O and Fe(NO3)3·9H2O solution are prepared. From the previous experimental data, it is found that the effect of 4mL of carboxyl-rich graphene oxide solution is the best, based on this, 1mL of the above metal ion solution is mixed with 4mL of carboxyl-rich graphene oxide solution to obtain ten groups of different content of decontamination solution. The experimental process and exploration of GO and CGO decontamination in this part are the same, still taking 500mL single-necked round-bottomed spherical bottle as the device main body, using a microsyringe to take 630μL of unsymmetrical dimethylhydrazine light yellow liquid, injecting into 100mL of water, stirring for 10min and standing for 1h, waiting for the bottle to reach the gas-liquid two-phase equilibrium state, then detecting with an unsymmetrical dimethylhydrazine gas detector, and recording the data of the first hour. Then, add the rising ten groups of different content of decontamination solution, stir for 10min, stand for 1h, and then detect the gas concentration after equilibrium. Then, the quantitative determination and calculation of the unsymmetrical dimethylhydrazine gas escape inhibition rate of different content of decontamination solution are carried out.

[0130] First, the exploration of Cu 2+ , Figure 12 shows the change of gas concentration value at 1h and 2h under different Cu 2+ concentrations, wherein the red column represents the gas concentration value at 1h, and the blue column represents the gas concentration value at 2h. From the overall trend, as the Cu 2+ concentration gradually increases from 10mmol / L to 90mmol / L, the gas concentration value at 1h and 2h is observed to decrease, indicating that the decontamination effect of the compounded decontamination solution on UDMH is exerted, and the content of UDMH in the gas phase is reduced.

[0131] Overall, as the Cu 2+ concentration increases, the concentration reduction amount does not present a simple linear relationship. In the range of 10-50mmol / L, the reduction amount gradually increases, indicating that the decontamination effect on UDMH is enhanced as the Cu 2+ concentration increases. However, at 70mmol / L, the reduction amount significantly decreases, and the decontamination effect is weakened. When the concentration reaches 90mmol / L, the reduction amount increases significantly, and the decontamination effect is significantly enhanced. This indicates that the influence of Cu 2+ concentration on UDMH decontamination effect is complex, and is not a simple positive correlation relationship. In different concentration ranges, the Cu 2+There may be differences in the mechanism of action of UDMH, which in turn leads to a complex change in the amount of concentration reduction.

[0132] Further analysis of Cu 2+ The complexation and catalytic mechanism of UDMH decontamination effect shows significant differences with concentration changes, mainly divided into three concentration intervals:

[0133] (1) In the low concentration interval (10-50 mmol / L), Cu 2+ The electronic configuration makes its empty orbital easy to form mononuclear weak complex (such as: [Cu(UDMH)] 2+ ) with the lone pair of electrons of nitrogen atom in UDMH molecule. Such complex makes the electron cloud of N-N bond in UDMH molecule shift to Cu 2+ , reduces the bond energy, significantly weakens the bond stability, and accelerates the oxidative decomposition. At the same time, Cu 2+ Catalyzes the oxidation reaction through single electron transfer mechanism, and the free Cu 2+ The linear increase of concentration increases the active site density, and in turn increases the generation rate of oxidation products.

[0134] (2) When the concentration reaches the inflection point (70 mmol / L), the coordination site of UDMH is saturated, forming a polynuclear complex, which wraps the catalytic site of Cu 2+ , reduces the efficiency of electron transfer, and significantly reduces the oxidation reaction rate. In addition, the high concentration of interionic electrostatic repulsion is weakened, forming a colloidal aggregate with a particle size of >100 nm, which reduces the efficiency of electron transfer and reduces the catalytic surface area, resulting in a sharp decrease in the amount of concentration reduction. At the same time, impurity ions will compete with UDMH for coordination, forming stable heteroleptic complexes, reducing the available Cu 2+ Concentration, further weakening the decontamination effect.

[0135] (3) In the high concentration interval (90 mmol / L), a strong complex of bidentate coordination is formed, which fixes the UDMH molecule into a "pincer" structure. At the same time, high concentration of Cu 2+ Through Fenton-like reaction to produce reactive oxygen species, ·OH can directly attack the C-H bond in UDMH molecule, and initiate chain decomposition reaction, which greatly increases the amount of concentration reduction compared with 70 mmol / L.

[0136] In summary, the decontamination efficiency of Cu 2+ UDMH is determined by the dynamic balance of complex stability and catalytic activity, and different concentration intervals show different dominant mechanisms. Based on the above data analysis, it is concluded that when the concentration of Cu 2+ is 90 mmol / L, the effect of decontaminant shows the best state.

[0137] Then the Fe3+ Through the investigation, Figure 13 It can be seen that, from an overall trend perspective, with Fe... 3+ As the concentration gradually increased from 10 mmol / L to 90 mmol / L, the gas phase concentrations initially showed an overall decreasing trend, but the difference in concentration reduction between the two time points was not linear. This indicates that the compounded Fe... 3+ Decontamination agents exhibit different mechanisms of action and principles when used to treat UDMH, leading to complex variations in the amount of concentration reduction. The specific reasons are analyzed below:

[0138] (1) In the low concentration range (10 mmol / L), Fe 3+ The empty orbitals of the nitrogen atom in the UDMH molecule form mononuclear complexes with the lone pair electrons of the nitrogen atom (e.g., [Fe(UDMH)]). 3+ Although this complex is monodentate, it exhibits high selectivity at low concentrations. Fe 3+ The nitrogen atom coordination with UDMH stabilizes the reaction, making the main reaction pathway more efficient. Meanwhile, at low concentrations, Fe... 3+ Predominantly in the free state, with a uniform distribution of active sites per unit volume, the oxidation reaction is promoted through a single-electron transfer mechanism, forming a kinetic characteristic of "rapid reaction + continuous diffusion".

[0139] (2) When Fe 3+ When the concentration was increased to 90 mmol / L, the system underwent significant changes. UDMH molecules reacted with Fe. 3+ Formation of bidentate chelates (e.g., [Fe(UDMH)2]) 3+ ), leading to Fe 3+ The octahedral coordination field is saturated, and its catalytic active center is shielded by ligands, thus reducing the oxidation reaction rate. Furthermore, Fe... 3+ Significant hydrolysis occurs at high concentrations, with the generated Fe(OH)3 colloidal particles adsorbing onto the reactor wall or forming aggregates, reducing the effective catalytic surface area. Simultaneously, the H2 produced by hydrolysis... + Inhibiting the protonation reaction of UDMH increases its tendency to escape into the gas phase. High concentration of Fe 3+ It also forms stable chelates with impurities in the system, consuming a large amount of Fe. 3+ Total amount, remaining Fe 3+ The complexation efficiency decreases.

[0140] In summary, Fe 3+ The detergency against UDMH is governed by a dual equilibrium of complexation and hydrolysis. At low concentrations, mononuclear complexation dominates the efficient reaction, while at high concentrations, efficiency declines due to chelation saturation and hydrolysis side reactions. Combined with analytical and experimental data, it can be seen that Fe... 3+The concentration of 10 mmol / L has the best effect on UDMH gas escape inhibition, and the higher the concentration, the better the effect.

[0141] After exploring the best concentration of Cu 2+ and Fe 3+ respectively, the washing and cleaning effects of two different ions were compared longitudinally, and the results are shown in Figure 14 . Figure 14 It is found that the average value of Cu 2+ on the inhibition rate of UDMH gas concentration escape is 18.28%, and the average value of Fe 3+ on the inhibition rate of UDMH gas concentration escape is 27.7%. It shows that Fe 3+ plays a more obvious role in the washing and cleaning agent solution, and the effect is better. The possible reasons are as follows:

[0142] (1) In terms of redox ability, Fe 3+ is more oxidizing than Cu 2+ , which can react with the reducing groups such as amine groups in UDMH to form non-volatile products and inhibit gas escape; in addition, from the stability of reaction products, Fe 3+ forms more stable complexes or complexes, which can tightly bind UDMH and reduce gas escape, while Cu 2+ products are relatively unstable.

[0143] (2) In terms of adsorption capacity, Fe 3+ has strong electrostatic or coordination interaction with UDMH, which can fix the molecules, while Cu 2+ has weak interaction, and UDMH is easy to escape.

[0144] (3) Fe 3+ may form a synergistic coordination network with ligands and solvent molecules in the system to limit the diffusion of UDMH, but Cu 2+ has weak synergistic effect.

[0145] These factors make Fe 3+ have higher inhibition rate on UDMH gas concentration escape than Cu 2+ , and show better inhibition effect.

[0146] To explore the washing and cleaning effect of metal ions on UDMH, further experiments were carried out by Fe 3+ and Cu 2+ with the best concentration. Because this experiment uses single factor comparison method, only one ion is added in the complex solution during the experiment, and the experimental data is shown in Table 3.

[0147] Table 3 Comparison of escape inhibition rate

[0148]

[0149] The results in Table 3 show that adding only one type of Fe... 3+ or Cu 2+ The effect on the escape suppression rate of unsymmetrical dimethylhydrazine (UDMH) is not good. However, if both ions are added simultaneously, the escape suppression rate increases by about 15%. This fully demonstrates that Fe... 3+ and Cu 2+ There may be a synergistic inhibitory mechanism between the two ions. The specific analysis is as follows:

[0150] (1)Fe 3+ and Cu 2+ Due to the difference in standard electrode potentials, a transmetallic electron transport chain is formed. Fe 3+ Preferential oxidation of amine groups in UDMH to generate Fe 2+ Cu 2+ Then capture Fe 2+ The released electrons are regenerated into Cu. 2+ This cyclical mechanism improves electron transfer efficiency, thereby increasing the rate of oxidation product formation.

[0151] (2)Fe 3+ and Cu 2+ The coordination characteristics are complementary, forming a bimetallic cooperative coordination network. Fe 3+ Cu coordinates with the highly electronegative N atom in UDMH via monodentate coordination, weakening the N-N bond; 2+ The N-N bonds are further stretched through bidentate coordination. The synergistic effect of these two mechanisms lowers the activation energy of the UDMH molecule, thereby increasing the decomposition rate.

[0152] (3)Fe 3+ With Cu 2+ The hydrolysis behaviors of the two elements are mutually constrained, thus optimizing the reaction microenvironment. Fe 3+ Hydrolysis produces acid, lowering the pH of the system, while Cu 2+ Low degree of hydrolysis, consuming H + Maintain pH stability. This pH range represents the optimal overlap between UDMH protonation and metal ion catalytic activity, facilitating contact between UDMH and metal ions while preventing metal ion precipitation.

[0153] In summary, Fe 3+ and Cu 2+ The synergistic effect of these substances significantly improves the scavenging effect on UDMH by enhancing electron transfer, optimizing coordination structure, and regulating reaction environment.

[0154] 3. Study on the decontamination performance of CGO combined with surfactants

[0155] The present invention uses sodium dodecylbenzenesulfonate (C 18 H29 SO3Na) as a complex solution. First, prepare 0.2 g / L, 0.5 g / L, 1 g / L, and 3 g / L sodium dodecyl benzene sulfonate solutions of four concentrations, and perform experimental operations on the basis of unchanged experimental methods to explore the optimal surfactant concentration.

[0156] By Figure 15 It can be seen that under the complex conditions of four concentrations of surfactants, the escape of unsymmetrical dimethylhydrazine gas is inhibited, and it is found from the data observation that the escape inhibition effect of unsymmetrical dimethylhydrazine gas is best at the concentration of 0.5 g / L.

[0157] The inhibition principle of surfactants can be analyzed from the following aspects:

[0158] (1) It can reduce the surface tension of the solution. The hydrophilic sulfonate group of the sodium dodecyl benzene sulfonate molecule faces the water phase, and the hydrophobic dodecyl chain faces the gas phase, and is arranged in the solution surface, thereby reducing the surface tension. The solution with low surface tension is more easily contacted with UDMH gas, increases the gas-liquid contact area, and is beneficial to the absorption of UDMH.

[0159] (2) When the concentration reaches the critical micelle concentration (CMC), the sodium dodecyl benzene sulfonate molecules will form micelles in the solution, and the hydrophobic alkyl chain will be aggregated inward, and the hydrophilic sulfonate group will be outward. Among them, UDMH as an organic compound with certain hydrophobicity can be wrapped in the hydrophobic core of the micelle, thereby increasing its solubility in the solution and promoting the transfer of UDMH in the gas phase to the liquid phase. Third, the sodium dodecyl benzene sulfonate will be adsorbed on the gas-liquid interface, change the interface properties, reduce the chemical potential of UDMH in the gas phase, and promote more UDMH to be distributed from the gas phase to the liquid phase. At the same time, the surfactant molecules adsorbed on the interface may interact with the UDMH molecules, such as van der Waals force, etc., further promoting absorption. However, when the concentration is too high, the solution viscosity may increase, which is not conducive to mass transfer.

[0160] In summary, sodium dodecyl benzene sulfonate effectively improves the gas phase absorption efficiency of UDMH by reducing the surface tension, forming micelles to increase solubility, changing the interface properties, and affecting the mass transfer process.

[0161] 4、CGO with metal ions, surfactant complex decontamination performance research

[0162] According to the previous experimental exploration, it is found that the two kinds of metal ions and surfactants have the best effect when they are co-compounded, which shows that the compounded UDMH decontamination solution can not only inhibit the gas phase escape of UDMH, but also effectively reduce the gas phase concentration in the closed system, and maintain the gas phase concentration in the system at a low level. This not only improves the safety and reliability of UDMH decontamination, but also enhances the decontamination efficiency, provides strong technical support and material guarantee for timely and efficient handling of leakage accidents, and helps to minimize the loss and adverse effects caused by leakage accidents.

[0163] Based on the analysis and summary of the previous experimental data, the best complexing concentration is determined as follows: 4 mL of CGO solution, 1 mL of 90 mmol / L Cu(NO3)2·3H2O solution, 1 mL of 10 mmol / L Fe(NO3)3·9H2O solution, and 1 mL of 0.5 g / L C 18 H 29 SO3Na solution. Further experiments prove that the escape inhibition rate of UDMH can reach 35.1%, which provides a key quantitative basis for the optimization of UDMH leakage treatment related technology.

[0164] Further analysis shows that the decontamination performance of carboxyl-rich graphene oxide (CGO) and metal ions, surfactants reaches the best effect after complexing, which is mainly due to the synergistic effect of the following three aspects, such as Figure 16

[0165] (1) CGO chemical adsorption

[0166] CGO provides rich active sites due to its porous structure and large specific surface area, which can efficiently adsorb UDMH molecules in the gas phase. When UDMH in the gas phase contacts with CGO, the chemical adsorption sites on the surface of CGO can quickly capture UDMH molecules, making them transfer from the gas phase to the solid surface. This chemical adsorption process not only reduces the concentration of UDMH in the gas phase, but also provides a high concentration of reactants for subsequent decontamination reactions, improving the decontamination efficiency.

[0167] (2) Lewis acid-base reaction of metal ions

[0168] Cu 2+ , Fe 3+ ​The ion as a Lewis acid reacts with UDMH in the complex system. The empty orbital of the metal ion can accept the lone pair of electrons of the nitrogen atom in the UDMH molecule to form a stable complex. This complexation reaction significantly reduces the bond energy of the key chemical bond (such as N-N bond) in the UDMH molecule, thereby reducing the chemical stability of the UDMH and accelerating the oxidative decomposition of the UDMH. At the same time, the synergistic redox reaction between different metal ions further promotes the efficient transfer of electrons and enhances the oxidation ability of the UDMH.

[0169] (3) Surface active agent coating effect

[0170] The surface active agent plays a multi-faceted role in the system through its unique molecular structure. On the one hand, the surface active agent can arrange itself at the gas-liquid interface to reduce the surface tension of the solution, making it easier for the solution to contact the UDMH in the gas phase and increasing the probability of UDMH entering the liquid phase. On the other hand, when the concentration of the surface active agent reaches the critical micelle concentration (CMC), a micelle structure is formed. At this time, the UDMH molecules can be coated in the hydrophobic core of the micelle, thereby increasing their solubility in the liquid phase and promoting the transfer of UDMH in the gas phase to the liquid phase. At the same time, the surface active agent can also interact with CGO and metal ions, further enhancing the stability and reactivity of the system.

[0171] III. Research on gas-liquid equilibrium law based on carboxyl-rich graphene oxide escape inhibition

[0172] 1. Henry's law constant formula

[0173] The specific expression of Henry's law is as follows: at constant temperature and pressure, the solubility of a volatile solute (usually a gas) in a solution is proportional to the equilibrium partial pressure of the solute on the liquid surface. The mathematical expression is:

[0174]

[0175] where P is the partial pressure of the gas, H is the Henry's constant, and C is the mole fraction of the gas in the solution, i.e. the liquid concentration. Specifically, the Henry's constant H can reflect the amount of gas dissolved, and is mainly affected by temperature and is independent of pressure. However, Henry's law is only applicable to dilute solutions with small gas solubility, and is a approximate law, which is no longer accurate for high-pressure systems or concentrated solutions.

[0176] There are two methods to obtain the value of Henry's constant: model prediction and experimental data measurement. In this invention, Henry's constant H is calculated from experimental data as follows:

[0177]

[0178] In the formula, H is Henry's constant, P is the partial pressure of the gas, and C is the concentration of the liquid phase. From the ideal gas partial pressure formula, we get:

[0179]

[0180] In the formula, P * C is the total pressure of the gas phase. * Since the gas phase concentration is the total concentration, the gas phase concentration measured by the gas detector can be converted into the gas phase partial pressure using the partial pressure formula:

[0181]

[0182] It is known that under 25℃ conditions, P * For 101 kPa, C * The concentration value is 0.5 g / L, based on the gas phase concentration C measured by the UDMH gas detector. i The partial pressure of the gas phase can then be calculated.

[0183] Theoretically, C in Henry's Law formula and C in the ideal gas partial pressure formula are different. * The numerical values ​​are equal, but due to certain random and systematic errors in the preparation of the unsymmetrical dimethylhydrazine solution, the theoretical calculations in this experiment are optimized to further reduce the impact of these errors. The specific optimization formula is as follows:

[0184]

[0185] Here, variable k is introduced as a measure of the change in the comparison value of the Henry's coefficient. 0i H is the initial equilibrium concentration value after 1 hour; H li H represents the equilibrium concentration value after adding the decontamination agent for 2 hours. When the k value is greater than 1, it indicates that the added decontamination agent is effective, reducing the equilibrium concentration of the gas phase before and after addition, thus increasing the ratio of the Henry's coefficient before and after addition. Furthermore, the larger the k value, the better the decontamination performance. The specific calculation steps are as follows:

[0186]

[0187] In the formula, p0 is the initial partial pressure of the gas; p l The partial pressure of the gas after adding the decontaminant; CO and C l All are liquid concentrations; C 0i The concentration of unsymmetrical dimethylhydrazine gas measured at initial equilibrium after 1 hour; C li The concentration of unsymmetrical dimethylhydrazine gas was measured after adding the decontamination agent for 2 hours and equilibrating.

[0188] 2. Calculation of Henry's coefficient

[0189] Because Henry's law is an important law for theoretically measuring the solute concentration distribution relationship of gas-liquid two phases in the equilibrium state, Henry's law has a key significance in the UDMH decontamination performance evaluation research. By measuring the distribution of UDMH between gas-liquid two phases under different conditions, the Henry coefficient is calculated according to Henry's law, which intuitively reflects the tendency of UDMH escaping from the liquid phase to the gas phase.

[0190] From the theoretical analysis level, when the proportion of each component in the complex system changes, the Henry coefficient also changes. Taking the CGO and metal ion, surfactant complex system as an example, when the amount of CGO is increased, the adsorption site of the system to UDMH increases, part of UDMH is fixed in the liquid phase, which makes it more difficult to escape from the liquid phase to the gas phase, and the Henry coefficient decreases. After the addition of metal ions, it may also change the existence form of UDMH by chemical reaction between them, reduce its volatility, and then affect the decrease of Henry coefficient. The surfactant can reduce the surface tension of the liquid, change the properties of the gas-liquid interface, so that UDMH tends to stay in the liquid phase, which also affects the Henry coefficient.

[0191] The specific calculation method is as follows: the mass concentration of the prepared UDMH solution is 0.5 g / L, the molar mass is 60.1 g / mol, which is converted into the amount of substance concentration of 0.0083 mol / L, and the unit of Henry constant is kPa L / mol. According to the above calculation method, the calculation results are as follows:

[0192] (1) Different concentrations of CGO

[0193] The calculation results in Table 4 show that after adding CGO solution, the Henry coefficient decreases, which shows that the content of carboxylated graphene oxide can change the equilibrium limit of gas-liquid phase, and when the CGO content reaches 4 mL, it can cause the Henry coefficient of volatile substances to decrease by about 54%, and fewer UDMH molecules enter the gas phase.

[0194] Table 4 Comparison of Henry coefficients under different amounts of CGO

[0195]

[0196] (2) Fe 3+ and Cu 2+ Metal ion addition amount

[0197] The calculation results in Table 5 show that with the increase of Fe 3+ The Henry coefficient decreases, and the K value is greater than 1. The decontamination effect is best when the complex concentration of Fe 3+ is 10 mmol / L.

[0198] Table 5 Fe 3+Comparison of Henry coefficient at different concentrations

[0199]

[0200] Table 6 Cu 2+ Comparison of Henry coefficient at different concentrations

[0201]

[0202] The calculation results in Table 6 show that, with the increase of the Cu 2+ With the increase of the complexing concentration, the Henry coefficient presents a downward trend, the K value is greater than 1, and the higher the concentration, the better the decontamination effect, and the Cu 2+ The concentration of 90 mmol / L reaches the best effect.

[0203] (3) Surfactant

[0204] The calculation results in Table 7 show that, with the increase of the complexing concentration of the surfactant, the Henry coefficient presents a downward trend, the K value is greater than 1, but the higher the concentration of the added surfactant, the worse the decontamination effect, and the concentration of 0.5 g / L reaches the best effect.

[0205] Comparison of Henry coefficient at different concentrations of surfactant

[0206]

[0207] To sum up, the decontaminant is compounded and optimized on the basis of the original CGO water-based solution, and through multi-factor complexing optimization, the best complex decontaminant composition is determined as 4 mL of CGO, 1 mL of 90 mmol / L Cu(NO3)2·3H2O solution, 1 mL of 10 mmol / L Fe(NO3)3·9H2O solution and 1 mL of 0.5 g / L surfactant solution, and it is verified through experiments that the complex decontaminant after compounding can improve the decontamination performance to 35.1%. The relationship between the concentration and the partial pressure is quantitatively verified by calculating the Henry coefficient, and the Henry coefficient presents a downward trend, and the K value is above 1. The operability and reliability of the application are further confirmed, and the comparison method of theory and experiment provides support for the application of experimental data and results of the application.

[0208] Although the embodiments of the application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the application, and the scope of the application is defined by the claims and their equivalents.

Claims

1. A composite decontaminant, characterized in that, Made from the following parts by volume of raw materials: Four parts of carboxyl-rich graphene oxide solution, one part of copper nitrate solution, one part of ferric nitrate solution, and one part of surfactant solution.

2. The composite decontaminant according to claim 1, characterized in that, The concentration of the carboxyl-rich graphene oxide solution was 17.8 g / L, the concentration of the copper nitrate solution was 90 mmol / L, the concentration of the ferric nitrate solution was 10–30 mmol / L, and the concentration of the surfactant solution was 0.5 g / L.

3. The composite decontaminant according to claim 1, characterized in that, The surfactant solution is a sodium dodecylbenzenesulfonate solution.

4. A method for preparing a composite decontaminant according to any one of claims 1-3, characterized in that, Includes the following steps; S1. Preparation of carboxyl-rich graphene oxide solution; S2. Measure 4 parts of carboxyl-rich graphene oxide solution, 1 part of copper nitrate solution, 1 part of ferric nitrate solution and 1 part of surfactant solution according to volume fraction, and set aside. S3. Mix the solutions measured in step 2 evenly to obtain a composite disinfectant.

5. The method for preparing a composite decontaminant according to claim 4, characterized in that, S1 includes the following steps: S11. Dissolve graphene oxide powder in water and ultrasonically disperse for 1 hour to obtain graphene oxide dispersion. S12. Chloroacetic acid was added to the graphene oxide dispersion and stirred for 3 hours. After the reaction was completed, the mixture was centrifuged, washed with water, and then freeze-dried to obtain carboxyl-rich graphene oxide powder. S13. Prepare a carboxyl-rich graphene oxide solution from carboxyl-rich graphene oxide powder.

6. The application of a composite decontaminant according to any one of claims 1-3 in the adsorption of unsymmetrical dimethylhydrazine propellant.

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