A polymer-based ammonia adsorbent and its preparation method

Abstract

This invention discloses a polymer-based ammonia adsorbent and its preparation method. The polymer-based adsorbent achieves highly efficient ammonia adsorption primarily through the coordination of metal ions. First, vinylimidazole is quaternized with a polyhalogenated alkane-substituted benzene, followed by a chelation reaction with a metal halide to functionalize the pre-product. Finally, the chelated product undergoes free radical cross-linking polymerization to obtain the functionalized polymer-based ammonia adsorbent. This adsorbent exhibits extremely high adsorption capacity for ammonia, reaching 26.59 mmol / g at 25℃ and 100 kPa. Furthermore, this polymer-based adsorbent also possesses excellent regeneration performance and ammonia adsorption selectivity, demonstrating significant potential for industrial applications.

Description

Technical Field

[0001] This invention belongs to the field of new chemical materials, specifically relating to a polymer-based ammonia adsorbent with high-density metal sites and its preparation method. Background Technology

[0002] Ammonia is one of the world's most produced inorganic compounds, widely used in fertilizers, synthetic fibers, and chemicals. The development of the synthetic ammonia industry has driven progress in human society, but it has also brought ammonia pollution. On the one hand, ammonia has a strong, pungent odor; direct contact can damage the mucous membranes of the respiratory tract. When the concentration of ammonia in the environment reaches 25 mg / kg, it can irritate the eyes and skin, even causing chemical burns, leading to tearing, photophobia, and conjunctival congestion. Higher concentrations can even threaten life. On the other hand, ammonia emitted into the atmosphere reacts with SO2... x NO x Aerosol particles generated from the reaction of acidic gases are a significant source of PM2.5 (fine particulate matter). Furthermore, ammonia, as a hydrogen-rich fuel, is an excellent hydrogen energy carrier with zero carbon dioxide emissions, thus possessing great development potential in the field of fuel cells. From both environmental and resource utilization perspectives, the adsorption separation and recycling of ammonia are of paramount research importance.

[0003] Liquid absorption and solid adsorption are two typical methods for separating ammonia. To achieve efficient, selective, and reversible gas absorption or adsorption, the key is to find suitable liquid or solid adsorbents. In liquid absorption methods for ammonia separation, ionic liquids (ILs) and their analogues, deep eutectic solvents (DESs), are currently widely used liquid adsorbents. They share some similar properties, such as a wide liquid range, extremely low volatility, and unrestricted structural designability. However, the ionic nature of ILs and DESs results in high viscosity, which is unfavorable for practical applications as they require continuous transport in towers and pipelines. In contrast, solid adsorption does not have this problem because the solid adsorbent is typically fixed in two parallel towers for sequential adsorption and regeneration. Furthermore, solid adsorption generally requires lower regeneration energy input compared to liquid absorption. Therefore, the development of solid adsorbents is of great significance for industrial development.

[0004] Currently, the main adsorbents used for ammonia adsorption and recovery both domestically and internationally include zeolites, activated carbon, graphene oxide, alumina, silica gel, and metal-organic frameworks. However, due to their limited number of functional sites, low density, and unstable structure, these materials often have low ammonia adsorption capacity. The purpose of this invention is to provide a high-density metal-site polymer-based ammonia adsorbent with high ammonia adsorption capacity. Summary of the Invention

[0005] To address the challenges posed by the aforementioned solid adsorbents, this invention presents a high-density metal-site polymer-based ammonia adsorbent with high ammonia adsorption capacity, good regenerability, and high selectivity. This polymer-based adsorbent achieves efficient ammonia adsorption primarily through the coordination of metal ions. First, vinylimidazole is quaternized with a polyhalogenated alkane-substituted benzene, followed by a chelation reaction with a metal halide to functionalize the pre-product. Finally, the chelated product undergoes free radical cross-linking polymerization to obtain the functionalized polymer-based ammonia adsorbent. This adsorbent exhibits extremely high ammonia adsorption capacity, reaching 26.59 mmol / g at 25 °C and 100 kPa. Furthermore, this polymer-based adsorbent also possesses excellent regeneration performance and ammonia adsorption selectivity, demonstrating significant potential for industrial applications.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A polymer-based ammonia adsorbent has the following structural features as shown in (1) or (2) or (3) or (4): Where M is one of the metals Ni, Co, Ca, Mg, Zn, Fe, Cu, Sr, Be, and Ba, n ranges from 1 to 3, and X and Y are Cl or Br.

[0007] The preparation method of the polymer-based ammonia adsorbent of the present invention includes the following steps: S1. A certain molar ratio of haloalkanes-substituted benzene and vinylimidazole is placed in a flask, and organic solvent a is added. The mixture is sonicated until the solid is completely dissolved in the solvent. Then, the mixture is heated in an oil bath under an inert atmosphere to allow the reaction to proceed. A stirring and reflux condenser should be used during the reaction. After the reaction is complete, the mixture is washed with organic solvent b, and finally dried under vacuum to obtain intermediate product 1.

[0008] S2. Intermediate product 1 and a metal halide are placed in a flask in a certain molar ratio. Organic solvent c is added, and the mixture is heated in an oil bath to allow the reaction to proceed. After the reaction is complete, the resulting mixture is rotary evaporated at a certain temperature and then dried under vacuum to obtain intermediate product 2.

[0009] S3. A certain amount of intermediate product 2 and azobisisobutyronitrile (AIBN) were placed in the lining of a hydrothermal reactor, and tetrahydrofuran and water were added in equal volume proportions. After stirring at room temperature for a certain time, the mixture was placed in the hydrothermal reactor and reacted in an oven at a certain temperature for a certain time. After the reaction was completed, the solvent in the lining of the hydrothermal reactor was evaporated at room temperature, and then dried in a vacuum drying oven for a certain time to obtain the polymer-based ammonia adsorbent.

[0010] Further, in step S1, the alkyl halobenzene is one of 1,4-di(chloromethyl)benzene, 1,4-di(bromomethyl)benzene, 1,3,5-tri(chloromethyl)benzene, 1,3,5-tri(bromomethyl)benzene, 1,2,4,5-tetra(chloromethyl)benzene, 1,2,4,5-tetra(bromomethyl)benzene, and hexabromomethylbenzene; the molar ratio of alkyl halobenzene to vinylimidazole is 1:2~6; organic solvent a is one of N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile; the reaction temperature of alkyl halobenzene and vinylimidazole is 60~100 °C; the reaction time of alkyl halobenzene and vinylimidazole is 12~48 h; organic solvent b is diethyl ether or ethyl acetate; the vacuum drying temperature is 40~120 °C, and the drying time is 12~48 h.

[0011] Further, in step S2, the metal halide is NiCl2, NiBr2, CoCl2, CoBr2, CaCl2, CaBr2, MgCl2, MgBr2, ZnCl2, ZnBr2, FeCl2, or CuCl2. 2、 One of SrCl2, BeCl2, and BaCl2; the molar ratio of intermediate product 1 to metal halide is 1:2~18; organic solvent c is one of ethanol, dimethyl sulfoxide, and methanol; the reaction temperature of intermediate product 1 and metal halide is 60~80 ℃; the rotary evaporation temperature is 40-80 ℃; the vacuum drying temperature is 60~100 ℃, and the drying time is 12~48 h.

[0012] Further, in step S3, the mass ratio of intermediate product 2 and azobisisobutyronitrile is 1:0.05~0.2; the stirring time at room temperature is 2~5 h; the reaction temperature in the oven is 100~160 ℃, and the reaction time is 24~36 h; the time for standing at room temperature after the reaction is completed is 12~48 h; the drying temperature in the vacuum drying oven is 80~120 ℃, and the drying time is 12~72 h.

[0013] Furthermore, the above-mentioned polymer-based ammonia adsorbent is used in ammonia adsorption and separation: the ammonia adsorbent adsorption temperature is 25~80 ℃, the adsorption pressure is 0~1.0 bar, the desorption temperature is 60~150 ℃, and the desorption pressure is 0~1.0 bar.

[0014] Beneficial effects of the present invention The advantages of the polymer-based ammonia adsorbent and its preparation method provided by this invention are mainly as follows: (1) The preparation method of this ammonia adsorbent is simple, the process conditions are simple and easy to control, it is easy to realize industrial production, and it has broad application prospects. (2) This ammonia adsorbent has an ultra-high ammonia absorption capacity, for example, its ammonia adsorption capacity can reach 26.5 mol / kg at 25 ℃ and 1 bar. (3) The functional groups of this ammonia adsorbent can be adjusted, and a variety of metal ions can be introduced as ammonia adsorption sites. (4) This ammonia adsorbent has good regeneration performance and high ammonia selectivity. Attached Figure Description

[0015] Figure 1 Diagram of ammonia static adsorption dual-reactor device; 1: Gas cylinder; 2: Storage chamber; 3: Adsorption chamber; 4: Water bath; 5-6: Pressure sensor; 7: Digital display; 8-10: Needle valve; 11: Temperature probe; 12: Vacuum pump; 13: Elevator; 14: Temperature controller; Figure 2 The XRD patterns are for adsorbents A, C, E, and NiCl2. Figure 3 The breakthrough test curve of adsorbent E in a ternary gas mixture (3 vol.%NH3 / 24.25 vol.%N2 / 72.75 vol.%H2) at 25 °C; Figure 4 The results show the repeated adsorption performance test results of adsorbent E at 40 °C and 1.1 bar for ammonia. Figure 5 The structure of the adsorbent is AI. Detailed Implementation

[0016] The present invention will be further illustrated by specific embodiments below, but the present invention is not limited to the following embodiments.

[0017] Example 1 1,4-bis(chloromethyl)benzene (0.035 mol, 6.25 g) and vinylimidazole (0.07 mol, 6.72 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The reaction was carried out under an argon atmosphere, heated to 70 °C, and stirred for 30 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [DCB-MVim][2Cl].

[0018] [DCB-MVim][2Cl] (0.004 mol, 1.74 g) and NiCl2 (0.008 mol, 1.04 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was completed, the mixture was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [DCB-MVim][Ni2Cl6].

[0019] 1.25 g of [DCB-MVim][Ni2Cl6] and 0.065 g of azobisisobutyronitrile were placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water in a 1:1 volume ratio were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 ℃ for 24 h. After the reaction was completed, the resulting product was allowed to evaporate at room temperature for 24 h, and then dried in a vacuum drying oven at 80 ℃ for 24 h to obtain a high-density metal site polymer-based ammonia adsorbent, denoted as adsorbent A.

[0020] Example 2 1,4-Di(bromomethyl)benzene (0.025 mol, 6.60 g) and vinylimidazole (0.050 mol, 4.71 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The reaction was carried out under an argon atmosphere at 70 °C with stirring for 30 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [DBB-MVim][2Br].

[0021] [DBB-MVim][2Br] (0.004 mol, 1.81 g) and NiCl2 (0.008 mol, 1.04 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was completed, the mixed solution was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [DBB-MVim][Ni2Cl4Br2].

[0022] 1.25 g of [DCB-MVim][Ni2Cl4Br2] and 0.065 g of azobisisobutyronitrile were placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water (volume ratio 1:1) were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the resulting product was allowed to evaporate at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal-site polymer-based ammonia adsorbent, denoted as Adsorbent B.

[0023] Example 3 1,4-Di(chloromethyl)benzene (0.035 mol, 6.25 g) and vinylimidazole (0.07 mol, 6.72 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The reaction was carried out under an argon atmosphere at 70 °C with stirring for 30 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [DCB-MVim][2Cl].

[0024] [DCB-MVim][2Cl] (0.004 mol, 1.74 g) and NiCl2 (0.016 mol, 2.07 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was complete, the mixture was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [DCB-MVim][Ni4Cl]. 10 ].

[0025] Take 1.25 g of [DCB-MVim][Ni4Cl] 10 0.065 g of azobisisobutyronitrile (AIBN) was placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water (volume ratio 1:1) were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the resulting product was volatilized at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal-site polymer-based ammonia adsorbent, denoted as adsorbent C.

[0026] Example 4 1,4-Di(bromomethyl)benzene (0.025 mol, 6.60 g) and vinylimidazole (0.050 mol, 4.71 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The reaction was carried out under an argon atmosphere at 70 °C with stirring for 30 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [DBB-MVim][2Br].

[0027] [DBB-MVim][2Br] (0.004 mol, 1.81 g) and NiCl2 (0.016 mol, 2.07 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was complete, the mixture was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [DBB-MVim][Ni4Cl]. 10 Br2].

[0028] Take 1.25 g of [DCB-MVim][Ni4Cl] 10 Br2] and 0.065 g of azobisisobutyronitrile were placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water in a 1:1 volume ratio were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the resulting product was volatilized at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal site polymer-based ammonia adsorbent, denoted as adsorbent D.

[0029] Example 5 1,4-Di(chloromethyl)benzene (0.035 mol, 6.25 g) and vinylimidazole (0.07 mol, 6.72 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The reaction was carried out under an argon atmosphere at 70 °C with stirring for 30 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [DCB-MVim][2Cl].

[0030] [DCB-MVim][2Cl] (0.004 mol, 1.74 g) and NiCl2 (0.024 mol, 3.11 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was complete, the mixture was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [DCB-MVim][Ni6Cl]. 14 ].

[0031] Take 1.25 g of [DCB-MVim][Ni6Cl] 14 0.065 g of azobisisobutyronitrile (AIBN) was placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water (volume ratio 1:1) were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the resulting product was allowed to evaporate at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal-site polymer-based ammonia adsorbent, denoted as adsorbent E.

[0032] Example 6 1,4-Di(bromomethyl)benzene (0.025 mol, 6.60 g) and vinylimidazole (0.050 mol, 4.71 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The reaction was carried out under an argon atmosphere at 70 °C with stirring for 30 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [DBB-MVim][2Br].

[0033] [DBB-MVim][2Br] (0.004 mol, 1.81 g) and NiCl2 (0.024 mol, 3.11 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was completed, the mixed solution was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [DBB-MVim][Ni4Cl8Br2].

[0034] 1.25 g of [DCB-MVim][Ni4Cl8Br2] and 0.065 g of azobisisobutyronitrile were placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water (volume ratio 1:1) were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the product was allowed to evaporate at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal-site polymer-based ammonia adsorbent, denoted as adsorbent F.

[0035] Example 7 1,3,5-tris(chloromethyl)benzene (0.005 mol, 1.12 g) and vinylimidazole (0.015 mol, 1.41 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The reaction was carried out under an argon atmosphere, heated to 100 °C, and stirred for 48 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [TrCB-MVim][3Cl].

[0036] [TrCB-MVim][3Cl] (0.004 mol, 2.02 g) and NiCl2 (0.036 mol, 4.66 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was complete, the mixture was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [TrCB-MVim][Ni6Cl]. 15 ].

[0037] Take 1.25 g of [TrCB-MVim][Ni6Cl] 15 0.065 g of azobisisobutyronitrile (AIBN) was placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water (volume ratio 1:1) were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the resulting product was volatilized at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal-site polymer-based ammonia adsorbent, denoted as adsorbent G.

[0038] Example 8 1,2,4,5-Tetra(chloromethyl)benzene (0.005 mol, 1.36 g) and vinylimidazole (0.020 mol, 1.88 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The mixture was heated to 100 °C and stirred under an argon atmosphere for 48 h. After the reaction was complete, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [TeCB-MVim][4Cl].

[0039] [TeCB-MVim][4Cl] (0.002 mol, 1.30 g) and NiCl2 (0.024 mol, 3.11 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was complete, the mixture was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [TeBB-MVim][NiCl2]. 12 Cl 28 ].

[0040] Take 1.25 g of [TeBB-MVim][Ni 12 Cl 28 0.065 g of azobisisobutyronitrile (AIBN) was placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water (volume ratio 1:1) were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the resulting product was volatilized at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal-site polymer-based ammonia adsorbent, denoted as adsorbent H.

[0041] Example 9 Hexabromomethylbenzene (0.005 mol, 3.18 g) and vinylimidazole (0.030 mol, 2.82 g) were placed in a flask, and 100 mL of N,N-dimethylformamide was added. The mixture was heated to 100 °C and stirred under an argon atmosphere for 48 h. After the reaction, the resulting mixture was washed five times with diethyl ether to remove unreacted reactants and solvent. Finally, the washed product was placed in a vacuum drying oven and dried at 80 °C for 24 h to obtain the intermediate product [HCB-MVim][6Br].

[0042] [HCB-MVim][6Br] (0.002 mol, 2.40 g) and NiCl2 (0.036 mol, 4.66 g) were placed in a flask, and 50 mL of ethanol was added. The mixture was then heated to 80 °C and stirred for 2 h. After the reaction was complete, the mixture was rotary evaporated at 70 °C to remove most of the solvent. The evaporated product was then dried in a vacuum drying oven at 80 °C for 12 h to obtain the intermediate product [HCB-MVim][6Br]. 18 Cl 36 Br6].

[0043] Take 1.25 g of [HCB-MVim][Ni 18 Cl 36 Br6] and 0.065 g of azobisisobutyronitrile were placed in the lining of a hydrothermal reactor, and 25 mL of tetrahydrofuran and water in a 1:1 volume ratio were added. After stirring at room temperature for 3 h, the mixture was transferred to the hydrothermal reactor and placed in an oven at 120 °C for 24 h. After the reaction was completed, the resulting product was volatilized at room temperature for 24 h, and then dried in a vacuum drying oven at 80 °C for 24 h to obtain a high-density metal site polymer-based ammonia adsorbent, denoted as Adsorbent I.

[0044] The test procedure for the static adsorption performance of ammonia is as follows: use Figure 1 The dual-reactor absorption device shown measures the ammonia adsorption performance of the adsorbent. For each measurement, approximately 0.1 g of sample is placed in the ammonia absorption tank.

[0045] The testing procedure for the dynamic adsorption performance of ammonia is as follows: In the test, approximately 0.15 g of adsorbent was fixed in a quartz tube and a flowing He gas was introduced. The tube was stabilized at the target temperature for 0.5 hours. Then, the He stream was switched to a mixed stream of 3 vol.% NH3 / 24.25 vol.% N2 / 72.75 vol.% H2, and the composition of the outlet gas was monitored using gas chromatography-mass spectrometry (GC-MS).

[0046] The ammonia circulation performance test process is as follows: Adsorption: Take approximately 0.1 g of adsorbent E and place it in... Figure 1 The ammonia absorption tank was introduced with ammonia gas at 40 °C. After the adsorption reached equilibrium, the amount of ammonia gas adsorbed at 1.1 bar was calculated.

[0047] Desorption: The sample saturated with ammonia adsorption was kept at 120 °C and 0 kPa for 2 h to allow it to desorb.

[0048] The regeneration performance of the adsorbent was measured by repeatedly performing the adsorption-desorption process under the same conditions.

[0049] Table 1. Ammonia adsorption capacity (mol / kg) of adsorbents A, C, and E at different pressures at 25 °C. Table 1 shows that this high-density metal site ammonia adsorbent has a high adsorption capacity for ammonia, and also has a high adsorption capacity for low concentrations of ammonia.

[0050] Figure 2 The XRD patterns of adsorbents A, C, and E show that the characteristic diffraction peaks of NiCl2 become more and more obvious with the increase of metal content. Figure 3 The table shows the selective adsorption curves of adsorbent E for a mixed gas of 3 vol.% NH3 / 24.25 vol.% N2 / 72.75 vol.% H2 at 25 °C. It can be seen that nitrogen and hydrogen penetrate instantaneously and reach adsorption equilibrium, while adsorbent E exhibits excellent selective adsorption capacity for ammonia. Figure 4 The data shows the ammonia adsorption capacity of adsorbent E after ten cycles. It can be seen that the ammonia adsorption capacity decreases slightly in the first cycle, but remains essentially unchanged in the next nine cycles, hovering around 19.89 mol / kg. This is higher than most previously reported materials, such as Co4(IDC)4(pda)4 reported by Chen Y et al., which has an NH3 adsorption capacity of only 11.5 mol / kg at 25 ℃ and 100 kPa, and BPP-5 reported by Van Humbeck J. F et al., which has an NH3 adsorption capacity of 17.70 mol / kg at 25 ℃ and 100 kPa. This demonstrates that the invented material has excellent recyclability and great potential for industrial application.

[0051] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A polymer-based ammonia adsorbent, characterized in that, It has the following structure (1) or (2) or (3) or (4): ； Where M is one of the metals Ni, Co, Ca, Mg, Zn, Fe, Cu, Sr, Be, and Ba, n ranges from 1 to 3, and X and Y are Cl or Br; The preparation method of the polymer-based ammonia adsorbent includes the following steps: S1. Place a certain molar ratio of haloalkanes-substituted benzene and vinylimidazole in a flask, add organic solvent a, sonicate until the solid is completely dissolved in the solvent, and then heat in an oil bath under an inert atmosphere to react. During the reaction, a stirring and reflux condenser should be provided. After the reaction is completed, wash the mixture obtained with organic solvent b, and finally dry under vacuum to obtain intermediate product 1. S2. Place intermediate product 1 and metal halide in a flask at a certain molar ratio, add organic solvent c, heat in an oil bath to react, after the reaction is completed, rotary evaporate the mixed solution at a certain temperature, and finally vacuum dry to obtain intermediate product 2. S3. A certain amount of intermediate product 2 and azobisisobutyronitrile are placed in the lining of a hydrothermal reactor, and tetrahydrofuran and water are added in equal volume proportions. After stirring at room temperature for a certain time, the mixture is loaded into the hydrothermal reactor and placed in an oven at a certain temperature for a certain time. After the reaction is completed, the solvent in the lining of the hydrothermal reactor is evaporated at room temperature, and then placed in a vacuum drying oven for a certain time to obtain a polymer-based ammonia adsorbent.

2. The method for preparing the polymer-based ammonia adsorbent according to claim 1, characterized in that, Includes the following steps: S1. Place a certain molar ratio of haloalkanes-substituted benzene and vinylimidazole in a flask, add organic solvent a, sonicate until the solid is completely dissolved in the solvent, and then heat in an oil bath under an inert atmosphere to react. During the reaction, a stirring and reflux condenser should be provided. After the reaction is completed, wash the mixture obtained with organic solvent b, and finally dry under vacuum to obtain intermediate product 1. S2. Place intermediate product 1 and metal halide in a flask at a certain molar ratio, add organic solvent c, heat in an oil bath to react, after the reaction is completed, rotary evaporate the mixed solution at a certain temperature, and finally vacuum dry to obtain intermediate product 2. S3. A certain amount of intermediate product 2 and azobisisobutyronitrile are placed in the lining of a hydrothermal reactor, and tetrahydrofuran and water are added in equal volume proportions. After stirring at room temperature for a certain time, the mixture is loaded into the hydrothermal reactor and placed in an oven at a certain temperature for a certain time. After the reaction is completed, the solvent in the lining of the hydrothermal reactor is evaporated at room temperature, and then placed in a vacuum drying oven for a certain time to obtain a polymer-based ammonia adsorbent.

3. The method for preparing a polymer-based ammonia adsorbent according to claim 2, characterized in that: In step S1, the alkyl halobenzene is one of 1,4-di(chloromethyl)benzene, 1,4-di(bromomethyl)benzene, 1,3,5-tri(chloromethyl)benzene, 1,3,5-tri(bromomethyl)benzene, 1,2,4,5-tetra(chloromethyl)benzene, 1,2,4,5-tetra(bromomethyl)benzene, and hexabromomethylbenzene; the molar ratio of alkyl halobenzene to vinylimidazole is 1:2~6; organic solvent a is one of N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile; the reaction temperature of alkyl halobenzene and vinylimidazole is 60~100 ℃; the reaction time of alkyl halobenzene and vinylimidazole is 12~48 h; organic solvent b is diethyl ether or ethyl acetate; the vacuum drying temperature is 40~120 ℃, and the drying time is 12~48 h.

4. The method for preparing a polymer-based ammonia adsorbent according to claim 2, characterized in that: In step S2, the metal halide is NiCl2, NiBr2, CoCl2, CoBr2, CaCl2, CaBr2, MgCl2, MgBr2, ZnCl2, ZnBr2, FeCl2, or CuCl2. 2、 One of SrCl2, BeCl2, and BaCl2; the molar ratio of intermediate product 1 to metal halide is 1:2~18; organic solvent c is one of ethanol, dimethyl sulfoxide, and methanol; the reaction temperature of intermediate product 1 and metal halide is 60~80 ℃; the rotary evaporation temperature is 40-80 ℃; the vacuum drying temperature is 60~100 ℃, and the drying time is 12~48 h.

5. The method for preparing a polymer-based ammonia adsorbent according to claim 2, characterized in that: In step S3, the mass ratio of intermediate product 2 and azobisisobutyronitrile is 1:0.05~0.2; the stirring time at room temperature is 2~5 h; the reaction temperature in the oven is 100~160 ℃, and the reaction time is 24~36 h; the time for standing at room temperature after the reaction is completed is 12~48 h; the drying temperature in the vacuum drying oven is 80~120 ℃, and the drying time is 12~72 h.

6. The application of the polymer-based ammonia adsorbent according to claim 1 in ammonia adsorption and separation.

7. The application according to claim 6, characterized in that: The ammonia adsorption temperature is 25~80 ℃, the adsorption pressure is 0~1.0 bar, the desorption temperature is 60~150 ℃, and the desorption pressure is 0~1.0 bar.

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