Green eutectic solvent with high efficiency and reversibility for absorbing ammonia gas, preparation method and application thereof

Abstract

This invention discloses a highly efficient and reversible green eutectic solvent for ammonia absorption, its preparation method, and its applications, belonging to the field of ammonia absorption and separation technology. The eutectic solvent uses a quaternary ammonium salt as a hydrogen bond acceptor and organic acids as hydrogen bond donors. Its preparation method includes the following steps: mixing the hydrogen bond acceptor and hydrogen bond donor at a molar ratio of 1:0.1–5, stirring until homogeneous at 60–120°C, drying under vacuum at 60–120°C, and cooling to room temperature to obtain the eutectic solvent. In the eutectic solvent prepared by this invention, the hydroxyl and carboxylic acid groups interact with ammonia molecules through hydrogen bonds, which is beneficial for achieving efficient ammonia absorption. Ammonia desorption and regeneration can be achieved through simple depressurization and heating operations. It features easy synthesis, easy regeneration, good stability, high ammonia absorption capacity, and low viscosity, and also shows good application prospects in ammonia separation and storage.

Description

Technical Field

[0001] This invention belongs to the field of ammonia absorption and separation technology, specifically relating to a eutectic solvent composed of quaternary ammonium salts as hydrogen bond acceptors and organic acids as hydrogen bond donors, and its application in the efficient and reversible absorption of ammonia. Background Technology

[0002] Ammonia (NH3) is a basic chemical raw material used in the manufacture of fertilizers, synthetic fibers, and plastics. As a hydrogen storage medium, it has advantages such as high energy density, low storage and transportation costs, zero carbon emissions at the end, high safety, and a mature industrial base. As an energy source, ammonia can be converted into hydrogen energy through ammonia decomposition reaction, and applied in hydrogen refueling stations and hydrogen-powered vehicles.

[0003] In recent years, my country has clearly proposed the goals of "carbon peaking" and "carbon neutrality," further promoting the development of efficient and clean secondary energy sources such as hydrogen energy. Due to its high hydrogen content, high energy density, convenient storage and transportation, and zero carbon emissions, NH3 has been considered a promising new type of chemical fuel and a long-distance, large-scale hydrogen energy carrier in recent years.

[0004] However, ammonia also poses certain hazards. NH3 is the only alkaline gas in the atmosphere and is readily oxidized to NO3. or NO x This leads to acid rain, which corrodes buildings. The accumulation of NH3 in the atmosphere contributes to the formation of PM2.5, causing smog and polluting the environment. The sources of atmospheric NH3 mainly include natural and anthropogenic sources. Natural sources primarily refer to release from plants, evaporation from oceans and lakes, and volatilization from soil. Anthropogenic sources mainly include emissions from agriculture, animal husbandry, and aquaculture, the combustion of traditional fossil fuels, and emissions from industrial production processes.

[0005] NH3 not only harms the environment but also threatens human health. Inhaling large amounts of ammonia gas in a short period of time can cause symptoms such as headache, nausea, and difficulty breathing. At excessively high concentrations, it can even cause respiratory arrest and cardiac arrest. Therefore, the harmful effects of ammonia on the human body should not be underestimated.

[0006] Direct emission of NH3 leads to the loss of this valuable resource and promotes the formation of PM2.5 particles. Therefore, the capture and separation of NH3 from exhaust gas is of great significance for environmental pollution control and the recycling of NH3. There are three traditional methods for treating NH3 emissions: (i) Acid washing, which uses ammonia (alkaline) to react chemically with an acidic absorbent to form a stable compound for fixation. It is highly selective and less affected by other gases. However, the acid used is very corrosive and will cause corrosion to the equipment, reducing its service life and increasing operating costs. In addition, the acid and ammonia will undergo an irreversible reaction, making the ammonia recovery process very difficult; (ii) Water absorption, which is simple to operate, requires low equipment, and has low cost. However, it uses a lot of water, has a low ammonia concentration, and low added value. After water absorption, ammonia water is formed, and subsequent treatment (such as ammonia recovery) requires additional energy. (III) Adsorption method: This method utilizes the surface pores or active sites of solid adsorbents (such as activated carbon, molecular sieves, and metal-organic frameworks (MOFs)) to capture ammonia through physical adsorption (van der Waals forces) or chemical adsorption (coordination bonds, acid-base interactions). It can achieve high-efficiency capture of low-concentration ammonia, and the adsorbent is regenerable with a long service life. However, its adsorption capacity is limited, requiring frequent regeneration, resulting in high energy consumption. The adsorbent is also susceptible to deactivation by water vapor and acidic gases, leading to high costs (especially for novel MOF materials, whose preparation processes are complex). Therefore, developing a pollution-free, highly efficient, and low-energy-consumption NH3 absorption and recovery technology is of great significance.

[0007] Ionic liquids have become a special subject for capturing toxic gases due to their extremely low vapor pressure, good thermal stability, and abundant designable structures. Numerous reports have already described ionic liquids as NH3 absorbents. However, the complex preparation processes, poor biodegradability, and high cost of ionic liquids greatly limit their large-scale application.

[0008] Eutectic solvents (DES), a novel type of green solvent, consist of hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs). They possess excellent properties similar to ionic liquids, and offer advantages in production cost and synthesis process. Their economical raw materials and simple preparation process make them truly "green solvents," with potential practical applications in the separation of CO2, SO2, and H2S. Because the hydrogen bond acceptors and donors of eutectic solvents contain abundant hydroxyl functional groups that can form hydrogen bonds with ammonia molecules, they have also been used in recent years for ammonia recovery.

[0009] Currently, most eutectic solvents used for ammonia absorption employ amides, azoles, metal chlorides, polyols, and resorcinol as hydrogen bond acceptors and donors, which are toxic and environmentally unfriendly. Therefore, designing a highly efficient and reversible natural eutectic solvent for ammonia absorption is of great significance for achieving energy-efficient utilization and ecological sustainability. Summary of the Invention

[0010] The purpose of this invention is to provide a green eutectic solvent for the efficient and reversible absorption of ammonia, its preparation method, and its application. Using quaternary ammonium salts as hydrogen bond acceptors and organic acids as hydrogen bond donors, the prepared eutectic solvent solves the problem of irreversible reactions in existing technologies through hydrogen bond interactions between hydroxyl and carboxyl groups and ammonia molecules, thereby synergistically achieving efficient and reversible absorption and desorption regeneration of ammonia.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] This invention provides a green eutectic solvent for the efficient and reversible absorption of ammonia. The eutectic solvent is composed of a quaternary ammonium salt as a hydrogen bond acceptor and a hydrogen bond donor, wherein the hydrogen bond donor is an organic acid.

[0013] Preferably, the quaternary ammonium salt is one of acetylcholine, choline chloride, betaine, carnitine, carbamoylcholine chloride, succinylcholine, 2-chloroethyltrimethylammonium chloride, yancoumon bromide, choline bicarbonate, tetrabutylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium chloride, tetramethylammonium sulfate, hexadecyltrimethylammonium nitrate, tetraethylammonium tetrafluoroborate, and tributylmethylammonium hexafluorophosphate.

[0014] Preferably, the organic acid is one of formic acid, acetic acid, propionic acid, n-butyric acid, acrylic acid, levulinic acid, methoxyacetic acid, ethoxyacetic acid, α-methacrylic acid, D-malic acid, L-malic acid, D-aspartic acid, L-aspartic acid, D-glutamic acid, L-glutamic acid, maleic acid, trans-butenedioic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, lactic acid, tartaric acid, citric acid, salicylic acid, gallic acid, glycolic acid, glyceric acid, 2-hydroxybutyric acid, and 3-hydroxypropionic acid.

[0015] Preferably, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:0.1 to 5.

[0016] The present invention also provides a method for preparing the above-mentioned highly efficient and reversible green eutectic solvent for ammonia absorption, comprising the following steps: mixing hydrogen bond acceptor and hydrogen bond donor at a molar ratio of 1:0.1 to 5, stirring at 60 to 120°C until homogeneous, drying under vacuum at 60 to 120°C, and cooling to room temperature to obtain the final product.

[0017] The present invention also provides an application of the above-mentioned highly efficient and reversible green eutectic solvent for absorbing and capturing ammonia.

[0018] Preferably, the highly efficient and reversible green eutectic solvent is used as the absorbent, which absorbs ammonia or a mixture containing ammonia at an absorption temperature of 20℃~80℃ and an absorption pressure of 0.01~0.1MPa; then a vacuum operation is performed to desorb the ammonia in the absorbent, so as to realize the regeneration of the absorbent and the recovery of ammonia.

[0019] Preferably, the highly efficient and reversible green eutectic solvent ammonia absorbent of the present invention can be regenerated by depressurization and heating after absorbing ammonia; the regeneration conditions are: temperature of 40℃~100℃ and regeneration pressure of 0.1KPa~20KPa, so that the eutectic solvent can be cyclically regenerated.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: Currently, most eutectic solvents are composed of amides, azoles, metal chlorides, polyols, and resorcinol as hydrogen bond acceptors and hydrogen bond donors. This invention proposes a stable eutectic solvent composed of quaternary ammonium salts as hydrogen bond acceptors and organic acids as hydrogen bond donors, thus expanding the range of eutectic solvents.

[0021] The highly efficient and reversible green eutectic solvent prepared by this invention has abundant raw materials and is simple to synthesize. It can achieve efficient and reversible absorption of ammonia through strong hydrogen bond interactions between multiple active sites on the hydroxyl and carboxyl groups and ammonia gas. The simple operation of heating and depressurization allows for convenient and effective desorption of ammonia from the solvent, exhibiting good recyclability and promising application prospects in the field of ammonia purification and separation.

[0022] The eutectic solvent prepared by this invention utilizes the hydroxyl and carboxylic acid groups in the eutectic solvent to provide abundant active sites for the absorption of ammonia, and can form hydrogen bond interactions with ammonia. It is suitable for the capture of ammonia in the exhaust gas emitted from the ammonia synthesis industry and chemical product production process, and can achieve selective absorption of ammonia.

[0023] The eutectic solvent provided by this invention has the characteristics of large ammonia absorption capacity, good stability, easy regeneration, and multiple recycling. Its raw materials are cheap and readily available, and the synthesis method is simple, which is conducive to large-scale production. It has potential application prospects in the absorption and storage of ammonia in industry. Attached Figure Description

[0024] Figure 1 These are ammonia absorption kinetic curves of choline chloride / lactic acid (ChCl / LA) eutectic solvents with different ratios prepared in this invention; Figure 2These are viscosity curves of different ratios of choline chloride / lactic acid (ChCl / LA) eutectic solvent prepared in this invention at different temperatures. Figure 3 This is a thermogravimetric analysis result of the choline chloride / lactic acid (ChCl / LA) eutectic solvent prepared in this invention; Figure 4 This is a differential scanning calorimetry curve of the choline chloride / lactic acid (ChCl / LA) eutectic solvent prepared in this invention; Figure 5 This is a graph showing the absorption results of five cycles of the eutectic solvent of choline chloride / lactic acid (ChCl / LA) prepared in this invention.

[0025] Figure 6 These are ammonia absorption kinetic curves of betaine / lactic acid (Bet / LA) eutectic solvents with different ratios prepared in this invention; Figure 7 These are viscosity curves of different ratios of betaine / lactic acid (Bet / LA) eutectic solvent prepared according to the present invention at different temperatures.

[0026] Figure 8 This is a thermogravimetric analysis result of the betaine / lactic acid (Bet / LA) eutectic solvent prepared in this invention; Figure 9 This is a differential scanning calorimetry curve of the betaine / lactic acid (Bet / LA) eutectic solvent prepared in this invention; Figure 10 This is a graph showing the absorption results of five cycles of the betaine / lactic acid (Bet / LA) eutectic solvent prepared in this invention. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0028] Unless otherwise specified, the instruments, reagents, and materials used in the following embodiments are all conventional instruments, reagents, and materials already available in the prior art and can be obtained through legitimate commercial channels. Unless otherwise specified, the experimental methods and detection methods used in the following embodiments are all conventional experimental methods and detection methods already available in the prior art.

[0029] This invention provides a green eutectic solvent for the efficient and reversible absorption of ammonia, which is composed of quaternary ammonium salts as hydrogen bond acceptors and organic acids as hydrogen bond donors. The quaternary ammonium salt is one of acetylcholine, choline chloride, betaine, carnitine, carbamoylcholine chloride, succinylcholine, 2-chloroethyltrimethylammonium chloride, yancoumonium bromide, choline bicarbonate, tetrabutylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium chloride, tetramethylammonium sulfate, hexadecyltrimethylammonium nitrate, tetraethylammonium tetrafluoroborate, and tributylmethylammonium hexafluorophosphate; the organic acid is one of formic acid, acetic acid, propionic acid, n-butyric acid, acrylic acid, levulinic acid, methoxyacetic acid, ethoxyacetic acid, α-methacrylic acid, D-malic acid, L-malic acid, D-aspartic acid, L-aspartic acid, D-glutamic acid, L-glutamic acid, maleic acid, trans-butenedioic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, lactic acid, tartaric acid, citric acid, salicylic acid, gallic acid, glycolic acid, glyceric acid, 2-hydroxybutyric acid, and 3-hydroxypropionic acid.

[0030] The method for preparing the eutectic solvent of the present invention specifically includes the following steps: mixing a hydrogen bond acceptor quaternary ammonium salt and a hydrogen bond donor organic acid at a molar ratio of 1:0.1 to 1:5, stirring at 60 to 120°C until a homogeneous liquid state is reached, then further drying under vacuum at 60 to 120°C for 18 to 24 hours, and finally cooling to room temperature to obtain the final product, the eutectic solvent.

[0031] The eutectic solvent of this invention absorbs ammonia at a temperature of 20℃ to 80℃ and an absorption pressure of 0.01MPa to 0.1MPa. The absorbent can be regenerated by heating and depressurizing; the regeneration temperature is 40℃ to 100℃ and the regeneration pressure is 0.1KPa to 20KPa. The regenerated solvent can be recycled. Notably, this regeneration can be achieved under conditions of higher temperature or lower pressure compared to the absorption conditions.

[0032] Example 1 Preparation of the eutectic solvent for the choline chloride / lactic acid system: 7.4775 g of choline chloride (hydrogen bond acceptor) was added to a 100 ml round-bottom flask. Based on a 1:5 molar ratio, 20 ml of lactic acid (hydrogen bond donor) was weighed and added to the flask. The mixture was then magnetically stirred in an oil bath at 80°C until a homogeneous and transparent liquid was formed. The prepared liquid was transferred to a vacuum drying oven and dried at 60°C for 24 hours. After cooling to room temperature, the final product, the eutectic solvent, was obtained.

[0033] Ammonia absorption and desorption process of the eutectic solvent in the choline chloride / lactic acid system: The eutectic solvent prepared above was transferred to a glass sample vial of approximately 40 ml. The vial was then passed through at a flow rate of 80 cm⁻¹ under conditions of a 40°C water bath and 0.1 MPa. 3Ammonia gas is introduced at a rate of [amount] / min, while the mixture is magnetically stirred until the eutectic solvent is saturated with ammonia. Excess gas flows into liquid paraffin and is eventually completely absorbed by water. The mass of the eutectic solvent and the mass of ammonia absorbed are obtained by weighing (the mass of the eutectic solvent before and after ammonia absorption is measured using an electronic balance; the mass difference is the mass of absorbed ammonia). The specific operation for desorption and regeneration of the eutectic solvent is as follows: the eutectic solvent after ammonia absorption is placed in an 80℃ vacuum drying oven at a pressure of 0.15 kPa for 24 hours. The desorbed eutectic solvent is weighed to obtain the mass of desorbed ammonia and the residual amount of ammonia.

[0034] The experiment of Example 1 was repeated under different molar ratios, with choline chloride as the hydrogen bond acceptor and lactic acid as the hydrogen bond donor. The specific eutectic solvent composition and molar ratio are shown in Table 1.

[0035] The absorption and desorption processes of ammonia in the eutectic solvent of choline chloride and lactic acid are the same as in Example 1, and the amount of ammonia absorbed by the eutectic solvent of choline chloride and lactic acid is shown in Table 1.

[0036] Table 1. Molar ratios of eutectic solvents with different compositions and ammonia absorption rates.

[0037] Table 1 shows the curves of ammonia absorption of the eutectic solvent in the choline chloride / lactic acid system over time. Figure 1 As shown in the figure, it can be seen that the eutectic solvent of the choline chloride / lactic acid system has a faster ammonia absorption rate, and its ammonia absorption increases with the increase of lactic acid content.

[0038] Viscosity affects mass and heat transfer between the gas and the absorbent during the absorption process, thus influencing absorption kinetics and the amount absorbed. Table 2 shows the viscosities of different ratios of choline chloride / lactic acid eutectic solvents at 40°C.

[0039] Table 2 Viscosities of eutectic solvents with different compositions

[0040] Viscosity curves of choline chloride / lactic acid eutectic solvents at different ratios at different temperatures are shown below. Figure 2 As shown, the viscosity of the choline chloride / lactic acid system increases with increasing choline chloride content. The viscosity of this system gradually decreases with increasing temperature.

[0041] For different ratios of choline chloride / lactic acid eutectic solvents, the ammonia absorption reached its maximum when the molar ratio of choline chloride / lactic acid was 1:5. The thermogravimetric analysis results and differential scanning calorimetry curves are shown below. Figure 3 , 4As shown, the eutectic solvothermal stability of the choline chloride / lactic acid system is good, and its properties are basically stable under desorption conditions at 80℃. The experimental results are safe and reliable.

[0042] The preparation process of the eutectic solvent in Example 1 was repeated. Under the condition of a molar ratio of 1:5, the eutectic solvent of the choline chloride / lactic acid system was prepared. The ammonia absorption temperature was changed by adjusting the water bath temperature, and the mixing ratio of nitrogen and ammonia was adjusted to adjust the partial pressure of ammonia. The experimental results are shown in Table 3, which proves that low temperature and high pressure are beneficial to the absorption of ammonia.

[0043] Table 3. Ammonia absorption of the eutectic solvent in the choline chloride / lactic acid system at different pressures and temperatures.

[0044] The ammonia absorption and desorption process of the eutectic solvent in Example 1 was repeated. Under the condition of a molar ratio of 1:5, the eutectic solvent of the choline chloride / lactic acid system was subjected to 5 repeated tests after the desorption operation was completed. The results of the cyclic desorption are as follows: Figure 5 As shown, the eutectic solvent of this system has good cycling performance, and its ammonia absorption capacity is almost unaffected after 5 cycles.

[0045] Example 2 Preparation of the eutectic solvent for the betaine / lactic acid system: 6.2737 g of betaine (hydrogen bond acceptor) was added to a 100 ml round-bottom flask. Based on a 1:5 molar ratio, 20 ml of lactic acid (hydrogen bond donor) was weighed and added to the flask. The mixture was then magnetically stirred in an oil bath at 80°C until a homogeneous and transparent liquid was formed. The prepared liquid was transferred to a vacuum drying oven and dried at 60°C for 24 hours. After cooling to room temperature, the final product, the eutectic solvent, was obtained.

[0046] Ammonia absorption and desorption process of the eutectic solvent in the betaine / lactic acid system: The eutectic solvent prepared above was transferred to a glass sample vial of approximately 40 ml. The vial was then passed through at a flow rate of 80 cm⁻¹ under conditions of a 40°C water bath and 0.1 MPa. 3 Ammonia gas is introduced at a rate of [amount] / min, while the mixture is magnetically stirred until the eutectic solvent is saturated with ammonia. Excess gas flows into liquid paraffin and is eventually completely absorbed by water. The mass of the eutectic solvent and the mass of ammonia absorbed are obtained by weighing (the mass of the eutectic solvent before and after ammonia absorption is measured using an electronic balance; the mass difference is the mass of absorbed ammonia). The specific operation for desorption and regeneration of the eutectic solvent is as follows: the eutectic solvent after ammonia absorption is placed in an 80℃ vacuum drying oven at a pressure of 0.15 kPa for 24 hours. The desorbed eutectic solvent is weighed to obtain the mass of desorbed ammonia and the residual amount of ammonia.

[0047] The experiment of Example 2 was repeated under different molar ratios, with betaine as hydrogen bond acceptor and lactic acid as hydrogen bond donor. The specific eutectic solvent composition and molar ratio are shown in Table 4.

[0048] The absorption and desorption processes of ammonia in the eutectic solvent of betaine lactic acid are the same as in Example 2, and the amount of ammonia absorbed by the eutectic solvent of betaine lactic acid is shown in Table 4.

[0049] Table 4. Molar ratios and ammonia absorption of eutectic solvents with different compositions

[0050] Table 4 shows the curves of ammonia absorption of the eutectic solvent in the betaine / lactic acid system over time. Figure 6 As shown in the figure, the eutectic solvent of the betaine / lactic acid system has a faster ammonia absorption rate, and its ammonia absorption increases with the increase of lactic acid content.

[0051] Viscosity affects mass and heat transfer between the gas and the absorbent during the absorption process, thus influencing absorption kinetics and the amount absorbed. Table 5 shows the viscosity of different ratios of betaine / lactic acid eutectic solvents at 40°C.

[0052] Table 5 Viscosities of eutectic solvents with different compositions

[0053] Viscosity curves of different ratios of betaine / lactic acid eutectic solvents at different temperatures are shown in the figure. Figure 7 As shown, the viscosity of the betaine / lactic acid system increases with increasing betaine content. The viscosity of this system gradually decreases with increasing temperature.

[0054] For different ratios of betaine / lactic acid eutectic solvents, the ammonia absorption reached its maximum when the molar ratio of betaine / lactic acid was 1:5. The thermogravimetric analysis results and differential scanning calorimetry curves are shown below. Figure 8 , 9 As shown, the eutectic solvothermal stability of the betaine / lactic acid system is good, and its properties are basically stable under desorption conditions at 80℃. The experimental results are safe and reliable.

[0055] The preparation process of the eutectic solvent in Example 2 was repeated. Under the condition of a molar ratio of 1:5, the eutectic solvent of the betaine / lactic acid system was prepared. The ammonia absorption temperature was changed by adjusting the water bath temperature, and the mixing ratio of nitrogen and ammonia was adjusted to adjust the partial pressure of ammonia. The experimental results are shown in Table 6, which proves that low temperature and high pressure are beneficial to the absorption of ammonia.

[0056] Table 6. Ammonia absorption of the eutectic solvent in the betaine / lactic acid system under different pressures and temperatures.

[0057] The ammonia absorption and desorption process of the eutectic solvent in Example 2 was repeated. Under the condition of a molar ratio of 1:5, the eutectic solvent of the betaine / lactic acid system was subjected to 5 repeated tests after the desorption operation was completed. The results of the cyclic desorption are as follows: Figure 10 As shown, the eutectic solvent of this system has good cycling performance, and its ammonia absorption capacity is almost unaffected after 5 cycles.

[0058] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention, or equivalent embodiments can be modified based on the disclosed technical content, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. A green eutectic solvent for the efficient and reversible absorption of ammonia, characterized in that, The eutectic solvent is composed of a quaternary ammonium salt as a hydrogen bond acceptor and a hydrogen bond donor; the hydrogen bond donor is an organic acid.

2. The green eutectic solvent for highly efficient and reversible ammonia absorption according to claim 1, characterized in that, The quaternary ammonium salt is one of acetylcholine, choline chloride, betaine, carnitine, carbamoylcholine chloride, succinylcholine, 2-chloroethyltrimethylammonium chloride, yancoumon bromide, choline bicarbonate, tetrabutylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium chloride, tetramethylammonium sulfate, hexadecyltrimethylammonium nitrate, tetraethylammonium tetrafluoroborate, and tributylmethylammonium hexafluorophosphate.

3. The green eutectic solvent for highly efficient and reversible ammonia absorption according to claim 1, characterized in that, The organic acids are one of the following: formic acid, acetic acid, propionic acid, n-butyric acid, acrylic acid, levulinic acid, methoxyacetic acid, ethoxyacetic acid, α-methacrylic acid, D-malic acid, L-malic acid, D-aspartic acid, L-aspartic acid, D-glutamic acid, L-glutamic acid, maleic acid, trans-butenedioic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, lactic acid, tartaric acid, citric acid, salicylic acid, gallic acid, glycolic acid, glyceric acid, 2-hydroxybutyric acid, and 3-hydroxypropionic acid.

4. The green eutectic solvent for highly efficient and reversible ammonia absorption according to claim 1, characterized in that, The molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:0.1 to 5.

5. The method for preparing the highly efficient, reversible, green eutectic solvent for ammonia absorption according to any one of claims 1-4, characterized in that, The process includes the following steps: mixing hydrogen bond acceptor and hydrogen bond donor at a molar ratio of 1:0.1 to 5, stirring at 60 to 120°C until homogeneous, drying under vacuum at 60 to 120°C, and cooling to room temperature to obtain the final product.

6. The application of the green eutectic solvent according to any one of claims 1-4, characterized in that, Used for the absorption and capture of ammonia.

7. The application of the green eutectic solvent according to claim 6, characterized in that, The regeneration temperature is set to 40℃~100℃ and the regeneration pressure is set to 0.1KPa~20KPa, so that the eutectic solvent is regenerated in a cyclic manner.

8. The application of the green eutectic solvent according to claim 6, characterized in that, The temperature for eutectic solvent absorption of ammonia is set at 20℃~80℃, and the absorption pressure is set at 0.01MPa~0.1MPa.

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