Ionic liquid modified active carbon fiber and method for trapping organic amine

Abstract

The invention provides an ionic liquid modified active carbon fiber and a method for capturing and purifying gas-phase organic amine escaped after decarburization of flue gas. The ionic liquid modified active carbon fiber is prepared by the following steps: 1) reacting active carbon fiber containing active groups with a substituted silane compound to obtain silane modified active carbon fiber; 2) reacting the silane modified active carbon fiber obtained in the step 1) with a nitrogen-containing ionic liquid precursor; and 3) carrying out anion exchange reaction on the product obtained in the step 2) and a salt solution containing specific anions. The ionic liquid modified activated carbon fiber can capture and purify gas-phase organic amine escaping after flue gas decarbonization, effectively reduces the concentration of discharged organic amine, recycles high-concentration organic amine for reuse, does not generate wastewater discharge, effectively reduces the cost, and has a very good application prospect in the field of carbon capture and separation post-treatment.

Description

Technical Field

[0001] The present invention belongs to the field of gas separation and purification, and relates to a modified activated carbon fiber and a method for capturing and purifying gaseous organic amines escaping after flue gas decarbonization using the modified activated carbon fiber. Background Art

[0002] The CCUS technology is an important way to achieve carbon neutrality and carbon peak. Among them, the solvent-based carbon capture is a potential capture method, and the organic amine solution is the current practical path for low-cost large-scale carbon capture. From the current domestic and international demonstration application projects, the volatilization and escape of gaseous amines are one of the potential hazards of secondary pollution in this process. Therefore, researchers and engineers have adopted the method of water washing to remove the escaping organic amines, which can reduce the emission of organic amines to a certain extent, but it also brings the problems of a large amount of low-concentration organic amines generated after water washing and difficult to utilize, and the amine concentration in the tail gas fluctuates greatly with the water temperature and seasons, making it difficult to meet the standards.

[0003] Therefore, there is an urgent need for a new method for efficiently capturing amines. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides an ionic liquid-modified activated carbon fiber and a method for capturing and purifying gaseous organic amines escaping after flue gas decarbonization using the ionic liquid-modified activated carbon fiber. The ionic liquid-modified activated carbon fiber selectively captures and absorbs organic amines in the exhaust gas of the absorption tower and enriches them in the functional ionic liquid functional sites and material pores of the ionic liquid-modified activated carbon fiber. When the organic amines enriched in the ionic liquid-modified activated carbon fiber reach a certain value, regeneration is carried out to realize the purification, recovery, and reuse of organic amines in the exhaust gas of the absorption tower.

[0005] According to the first aspect of the present invention, there is provided an ionic liquid-modified activated carbon fiber, which is prepared by the following steps:

[0006] 1) Reacting a carbon fiber containing an active group with a substituted silane compound to obtain a silane-modified activated carbon fiber, wherein the substituted silane compound is a silane substituted by one or more substituents selected from halogen, halo-C 1～6 alkyl, C 1～6 alkyl, and C 1～6 alkoxy, and the substituted silane compound contains at least one halo-C 1～6 alkyl and at least one C 1～6 alkoxy;

[0007] 2) React the silane-modified activated carbon fiber containing active groups obtained in step 1) with a nitrogen-containing ionic liquid precursor, wherein the nitrogen-containing ionic liquid precursor is selected from substituted or unsubstituted imidazole compounds, substituted or unsubstituted pyrrolidine compounds, quaternary amine compounds, substituted or unsubstituted pyridine compounds, substituted or unsubstituted piperidine compounds, substituted or unsubstituted piperazine compounds, and substituted or unsubstituted pyrrole compounds;

[0008] 3) React the product obtained in step 2) with a salt solution containing one or more of the following: Cl - , Br - , I - , BF4 - , PF6 - , NO3 - , ClO4 - , HSO3 - , HSO4 - , H2PO4 - , CH3COO - , CH3(CH2) p COO - , SCN - , SbF6 - , AsF6 - , CF3 - , CF3COO - , CH3SO4 - , C2H6SO4 - , C8H 17 SO4 - , C4F9SO3 - , CF3(CF2) p SO3 - , (CF3SO2)3C - , (C2F5SO2)2N - , (CF3SO2)2N - , CH3CH(OH)COO - , dodecylsulfonate, benzenesulfonate, and p-toluenesulfonate to carry out an anion exchange reaction to obtain an ionic liquid-modified activated carbon fiber, where p is independently an integer selected from 0 to 12, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12.

[0009] Preferably, the substituted silane compound is selected from halo C 1～6 alkyl C 1～6 alkoxysilane, bis(halo C 1～6 alkyl)C 1～6 alkoxysilane, tris(halo C 1～6 alkyl)C 1～6Alkoxysilane, (halo C 1～6 alkyl)di(C 1～6 alkoxy)silane, (halo C 1～6 alkyl)tri(C 1～6 alkoxy)silane, di(halo C 1～6 alkyl)di(C 1～6 alkoxy)silane, halo C 1～6 alkyl C 1～6Alkoxyhalosilanes; more preferably selected from chloropropylmethoxysilane, bis(chloropropyl)methoxysilane, tris(chloropropyl)methoxysilane, chloropropyldimethoxysilane, bis(chloropropyl)dimethoxysilane, chloropropyltrimethoxysilane, chloropropylethoxysilane, bis(chloropropyl)ethoxysilane, tris(chloropropyl)ethoxysilane, chloropropyldiethoxysilane, bis(chloropropyl)diethoxysilane, chloropropyltriethoxysilane, chloropropylpropoxysilane, bis(chloropropyl)propoxysilane, tris(chloropropyl)propoxysilane, chloropropyldipropoxysilane, bis(chloropropyl)dipropoxysilane, chloropropyltripropoxysilane, chloropropylbutoxysilane, bis(chloropropyl)butoxysilane, tris(chloropropyl)butoxysilane, chloropropyldibutoxysilane, bis(chloropropyl)dibutoxysilane, chloropropyltributoxysilane, chlorobutylmethoxysilane, bis(chlorobutyl)methoxysilane, tris(chlorobutyl)methoxysilane, chlorobutyldimethoxysilane, bis(chlorobutyl)dimethoxysilane, chlorobutyltrimethoxysilane, chlorobutylethoxysilane, bis(chlorobutyl)ethoxysilane, tris(chlorobutyl)ethoxysilane, chlorobutyldiethoxysilane, bis(chlorobutyl)diethoxysilane, chlorobutyltriethoxysilane, chlorobutylpropoxysilane, chlorobutyldipropoxysilane, chlorobutyltripropoxysilane, chlorobutylbutoxysilane, bis(chlorobutyl)butoxysilane, tris(chlorobutyl)butoxysilane, chlorobutyldibutoxysilane, bis(chlorobutyl)dibutoxysilane, chlorobutyltributoxysilane, chloropentylmethoxysilane, bis(chloropentyl)methoxysilane, tris(chloropentyl)methoxysilane, chloropentyldimethoxysilane, bis(chloropentyl)dimethoxysilane, chloropentyltrimethoxysilane, chloropentylethoxysilane, bis(chloropentyl)ethoxysilane, tris(chloropentyl)ethoxysilane, chloropentyldiethoxysilane, bis(chloropentyl)diethoxysilane, chloropentyltriethoxysilane, chloropentylpropoxysilane, bis(chloropentyl)propoxysilane, tris(chloropentyl)propoxysilane, chloropentyldipropoxysilane, bis(chloropentyl)dipropoxysilane, chloropentyltripropoxysilane, chloropentylbutoxysilane, bis(chloropentyl)butoxysilane, tris(chloropentyl)butoxysilane, chloropentyldibutoxysilane, bis(chloropentyl)dibutoxysilane, chloropentyltributoxysilane, chlorohexylmethoxysilane, bis(chlorohexyl)methoxysilane, tris(chlorohexyl)methoxysilane, chlorohexyldimethoxysilane, bis(chlorohexyl)dimethoxysilane, chlorohexyltrimethoxysilane, chlorohexylethoxysilane, bis(chlorohexyl)ethoxysilane, tris(chlorohexyl)ethoxysilane, chlorohexyldiethoxysilane, bis(chlorohexyl)diethoxysilane, chlorohexyltriethoxysilane, chlorohexylpropoxysilane, bis(chlorohexyl)propoxysilane, tris(chlorohexyl)propoxysilane, chlorohexyldipropoxysilane, bis(chlorohexyl)dipropoxysilane, chlorohexyltripropoxysilane, chloroethylethoxysilane, bis(chloroethyl)ethoxysilane, tris(chloroethyl)ethoxysilane,Chloroethyl diethoxysilane, bis(chloroethyl)diethoxysilane, chloroethyl triethoxysilane, chloroethyl methoxysilane, bis(chloroethyl)methoxysilane, tris(chloroethyl)methoxysilane, chloroethyl dimethoxysilane, bis(chloroethyl)dimethoxysilane, chloroethyl trimethoxysilane, chloroethyl propoxysilane, bis(chloroethyl)propoxysilane, tris(chloroethyl)propoxysilane, chloroethyl dipropoxysilane, bis(chloroethyl)dipropoxysilane or chloroethyl tripropoxysilane, more preferably 3-chloropropyltriethoxysilane or 3-chlorohexyltriethoxysilane.

[0010] Preferably, the weight ratio of the activated carbon fiber containing active groups to the substituted silane compound is 1:(0.01 - 1), more preferably 1:(0.2 - 1), further more preferably 1:(0.3 - 1), and further more preferably 1:(0.5 - 1).

[0011] Preferably, the activated carbon fiber containing active groups is one or more selected from phenolic fibers, PAN-based fibers, viscose-based fibers and pitch-based fibers.

[0012] Preferably, the active groups on the activated carbon fiber containing active groups are one or more selected from hydroxyl groups, carboxyl groups, phenolic groups, quinone groups, sulfur groups, nitrogen-containing groups and halogens.

[0013] The activated carbon fiber containing active groups can be commercially available, such as ACF-BOL activated carbon fiber, which contains hydroxyl active groups.

[0014] Preferably, the reaction conditions in step 1) are as follows: Cut the activated carbon fiber A containing active groups into square pieces of 3 - 5 cm, place the activated carbon fiber containing active groups in a flask, add a solvent and a substituted silane compound, and react under nitrogen protection and reflux condensation conditions to obtain a silane-modified activated carbon fiber.

[0015] Preferably, the solvent used in step 1) is one or several selected from acetonitrile, ethanol, ethylene glycol, glycerol, propanol, isopropanol, n-butanol, isobutanol, pentanol, dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, methyl ethyl ether, ethyl propyl ether, propyl butyl ether, polyethylene glycol dimethyl ether, ethyl acetate, butyl acetate, N-methyl-2-pyrrolidone, 2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide and sulfolane.

[0016] Preferably, the reaction conditions in step 1) are 60 - 100 °C and the reaction time is 1 - 15 hours.

[0017] Preferably, the precursor of the nitrogen-containing ionic liquid is one or more selected from the following compounds:

[0018]

[0019] Wherein, R1 and R2 are each independently H or -(CH2) n CH3, and at least one of them is -H, n is an integer between 0 and 12, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12; R3 to R9 are independently selected from -H, -(CH2) m CH3, -(CH2) m CH=CH2, and m is each independently an integer between 0 and 12, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12.

[0020] Preferably, the weight of the nitrogen-containing ionic liquid precursor added is 0.03 to 1 times, preferably 0.03 to 0.5 times, the weight of the activated carbon fiber containing active groups.

[0021] Preferably, the reaction conditions in step 2) are: mixing the silane-modified activated carbon fiber with the nitrogen-containing ionic liquid precursor in a solvent, and carrying out a reaction under nitrogen protection and reflux condensation.

[0022] Preferably, the concentration of the salt solution in step 3) is 0.01 to 5 mol / L.

[0023] Preferably, the solvent of the salt solution in step 3) is water.

[0024] By chemically reacting the acidic ionic liquid with functional groups such as rich carboxyl, phenolic, quinone, sulfhydryl, nitrogen-containing groups or halogens on the activated carbon fiber structure containing active groups, the active ionic liquid component is grafted onto the activated carbon fiber containing active groups through chemical bonds to form an ionic liquid-modified activated carbon fiber.

[0025] According to the second aspect of the present invention, there is provided a method for capturing and purifying gaseous organic amines escaping after flue gas decarbonization, which comprises the following steps:

[0026] a) Contacting the ionic liquid-modified activated carbon fiber according to the present invention with the gas after flue gas decarbonization purification.

[0027] The gas after flue gas decarbonization purification refers to the flue gas discharged after CO2 is captured by a CO2 absorption tower and washed with water.

[0028] The gaseous organic phase is components such as volatile organic amines in the solvent used for CO2 absorption, including but not limited to one or more of ammonia, ethanolamine, diethanolamine, triethanolamine, diisopropylamine, piperazine, hydroxyethyl ethylenediamine, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, etc.

[0029] Preferably, the contact conditions in step a) are: gas-solid contact mode, and the temperature is 10-60°C.

[0030] The method uses activated carbon fibers modified with ionic liquid to capture trace organic amine components contained in the exhaust gas from the absorption tower through gas-solid contact.

[0031] Preferably, the method for capturing and purifying the gaseous organic amine escaping after flue gas decarbonization further includes the following steps:

[0032] b) After the activated carbon fibers modified with ionic liquid are saturated by enrichment, the adsorbed organic amine is desorbed and regenerated by thermal evaporation to obtain a high-concentration organic amine solution, and the regenerated activated carbon fibers modified with ionic liquid are then continued to be used for capturing gaseous organic amine.

[0033] Preferably, the regeneration conditions in step b) are: 70-100°C, 10-50 kPa absolute pressure.

[0034] The method for capturing and purifying the gaseous organic amine escaping after flue gas decarbonization of the present invention can replace the traditional water washing process, effectively reduce the concentration of the discharged organic amine, and recycle the high-concentration organic amine for reuse without generating wastewater discharge, effectively reducing costs, and having good application prospects in the field of post-treatment of carbon capture and separation. Detailed implementation manners

[0035] The present invention will be described in detail below in conjunction with embodiments. It should be noted that the following embodiments are only used to illustrate the purpose of the present invention, rather than limiting the scope of the present invention.

[0036] Example 1

[0037] The activated carbon fiber A (ACF-BOL) containing hydroxyl groups was cut into square pieces of 3-5 cm, 3 g of the activated carbon fiber containing hydroxyl groups was weighed and placed in a flask, 50 mL of acetonitrile solvent and 2.4 g of 3-chloropropyltriethoxysilane were added, and the reaction was carried out at 80°C for 10 h under nitrogen protection and reflux condensation. After filtration, washing with acetonitrile and drying, the activated carbon fiber B modified with silane was obtained.

[0038] The activated carbon fiber B modified with silane and 0.72 g of 2-methylimidazole were placed in 50 mL of acetonitrile solution, and the reaction was carried out at 80°C under nitrogen protection and reflux condensation for 12 h. The product was filtered, washed with ethanol and dried to obtain the protonic acidic imidazole chloride modified activated carbon fiber C.

[0039] The protonic acidic imidazole chloride modified activated carbon fiber C was placed in a funnel, rinsed with a flowing sodium tetrafluoroborate solution, and then rinsed with deionized water to obtain the protonic acidic imidazole tetrafluoroborate modified activated carbon fiber D.

[0040] Place the protonic acidic imidazole tetrafluoroborate modified activated carbon fiber D in a funnel, rinse it with a flowing LiNTf2 solution, and then rinse it with deionized water to obtain the protonic acidic imidazole bis(trifluoromethanesulfonyl)imide modified activated carbon fiber E.

[0041] Example 2

[0042] Cut the activated carbon fiber A (ACF-BOL) containing hydroxyl groups into square pieces of 3 - 5 cm, weigh 3 g of the activated carbon fiber containing hydroxyl groups and place it in a flask, add 50 mL of acetonitrile solvent and 0.6 g of 3-chloropropyltriethoxysilane, react at 80 °C for 10 h under nitrogen protection and reflux condensation conditions, filter, wash with acetonitrile, and dry to obtain the silane modified activated carbon fiber B'.

[0043] Place the silane modified activated carbon fiber B' and 0.18 g of 2-methylimidazole in 50 mL of acetonitrile solution, react at 80 °C under nitrogen protection and reflux condensation for 12 h, filter the product, wash with ethanol, and dry to obtain the protonic acidic imidazole chloride modified activated carbon fiber C'.

[0044] Place the protonic acidic imidazole chloride modified activated carbon fiber C' in a funnel, rinse it with a flowing sodium tetrafluoroborate solution, and then rinse it with deionized water to obtain the protonic acidic imidazole tetrafluoroborate modified activated carbon fiber D'.

[0045] Place the protonic acidic imidazole tetrafluoroborate modified activated carbon fiber D' in a funnel, rinse it with a flowing LiNTf2 solution, and then rinse it with deionized water to obtain the protonic acidic imidazole bis(trifluoromethanesulfonyl)imide modified activated carbon fiber E'.

[0046] Example 3

[0047] Cut the activated carbon fiber A (ACF-BOL) containing hydroxyl groups into square pieces of 3 - 5 cm, weigh 3 g of the activated carbon fiber containing hydroxyl groups and place it in a flask, add 50 mL of acetonitrile solvent and 2.76 g of 3-chlorohexyltriethoxysilane, react at 80 °C for 10 h under nitrogen protection and reflux condensation conditions, filter, wash with acetonitrile, and dry to obtain the silane modified activated carbon fiber b.

[0048] Place the silane modified activated carbon fiber b and 0.72 g of 2-methylimidazole in 50 mL of acetonitrile solution, react at 80 °C under nitrogen protection and reflux condensation for 12 h, filter the product, wash with ethanol, and dry to obtain the protonic acidic imidazole chloride modified activated carbon fiber c.

[0049] Place the protonic acidic imidazole chloride modified activated carbon fiber c in a funnel, rinse it with a flowing sodium tetrafluoroborate solution, and then rinse it with deionized water to obtain the protonic acidic imidazole tetrafluoroborate modified activated carbon fiber d.

[0050] Place the protonic acidic imidazole tetrafluoroborate modified activated carbon fiber d in a funnel, rinse it with a flowing LiNTf2 solution, and then rinse it with deionized water to obtain the protonic acidic imidazole bis(trifluoromethanesulfonyl)imide modified activated carbon fiber e.

[0051] Example 4

[0052] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a 40 °C water bath and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the ethanolamine liquid surface and does not pass below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously pass the prepared simulated gas into another drying tube containing 2 g of silane-modified activated carbon fiber B and weigh it every 5 minutes. After 2 h, the weight of the drying tube containing silane-modified activated carbon fiber B no longer changes. The ethanolamine adsorption capacity of the component of the silane-modified activated carbon fiber B is 28% (weight percentage increase by the weighing method, ethanolamine adsorption capacity = (weight of the fiber after adsorbing ethanolamine - weight of the fiber before adsorbing ethanolamine) / weight of the activated carbon fiber before adsorbing ethanolamine).

[0053] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a 40 °C water bath and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the ethanolamine liquid surface and does not pass below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously pass the prepared simulated gas into another drying tube containing 2 g of protonic acidic imidazole chloride modified activated carbon fiber C and weigh it every 5 minutes. After 2 h, the weight of the drying tube containing protonic acidic imidazole chloride modified activated carbon fiber C no longer changes. The ethanolamine adsorption capacity of the component of the protonic acidic imidazole chloride modified activated carbon fiber C is 28%.

[0054] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a 40 °C water bath and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the ethanolamine liquid surface and does not pass below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously pass the prepared simulated gas into another drying tube containing 2 g of protonic acidic imidazole tetrafluoroborate modified activated carbon fiber D and weigh it every 5 minutes. After 4 h, the weight of the drying tube containing protonic acidic imidazole tetrafluoroborate modified activated carbon fiber D no longer changes. The ethanolamine adsorption capacity of the component of the protonic acidic imidazole tetrafluoroborate modified activated carbon fiber D is 52%.

[0055] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a water bath at 40 °C and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the surface of the ethanolamine and does not penetrate below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously introduce the prepared simulated gas into another drying tube containing 2 g of activated carbon fiber E modified with protonic acidic imidazole bis(trifluoromethanesulfonyl)imide, and weigh it every 5 minutes. After 4.5 h, the weight of the drying tube containing the activated carbon fiber E modified with protonic acidic imidazole tetrafluoroborate no longer changes, and the ethanolamine adsorption capacity of the component of the activated carbon fiber E modified with protonic acidic imidazole tetrafluoroborate is 60%.

[0056] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a water bath at 40 °C and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the surface of the ethanolamine and does not penetrate below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously introduce the prepared simulated gas into another drying tube containing 2 g of activated carbon fiber D' modified with protonic acidic imidazole tetrafluoroborate, and weigh it every 5 minutes. After 3.5 h, the weight of the drying tube containing the activated carbon fiber D' modified with protonic acidic imidazole tetrafluoroborate no longer changes, and the ethanolamine adsorption capacity of the component of the activated carbon fiber D' modified with protonic acidic imidazole tetrafluoroborate is 39%.

[0057] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a water bath at 40 °C and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the surface of the ethanolamine and does not penetrate below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously introduce the prepared simulated gas into another drying tube containing 2 g of activated carbon fiber E' modified with protonic acidic imidazole bis(trifluoromethanesulfonyl)imide, and weigh it every 5 minutes. After 3.5 h, the weight of the drying tube containing the activated carbon fiber E' modified with protonic acidic imidazole bis(trifluoromethanesulfonyl)imide no longer changes, and the ethanolamine adsorption capacity of the component of the activated carbon fiber E' modified with protonic acidic imidazole bis(trifluoromethanesulfonyl)imide is 42%.

[0058] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a water bath at 40 °C and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the surface of the ethanolamine and does not penetrate below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously introduce the prepared simulated gas into another drying tube containing 2 g of activated carbon fiber d modified with protonic acidic imidazole tetrafluoroborate, and weigh it every 5 minutes. After 4 h, the weight of the drying tube containing the activated carbon fiber d modified with protonic acidic imidazole tetrafluoroborate no longer changes, and the ethanolamine adsorption capacity of the component of the activated carbon fiber d modified with protonic acidic imidazole tetrafluoroborate is 54%.

[0059] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a water bath at 40 °C and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the ethanolamine liquid surface and does not pass below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously introduce the prepared simulated gas into another drying tube containing 2 g of activated carbon fiber e modified with protonic acidic imidazole bis(trifluoromethanesulfonate). Weigh it every 5 minutes. After 4.5 h, the weight of the drying tube containing the activated carbon fiber e modified with protonic acidic imidazole bis(trifluoromethanesulfonate) no longer changes, and the ethanolamine adsorption capacity of the component of the activated carbon fiber e modified with protonic acidic imidazole bis(trifluoromethanesulfonate) is 61%.

[0060] Example 5

[0061] Regenerate the activated carbon fiber E modified with protonic acidic imidazole bis(trifluoromethanesulfonate) that is saturated with adsorption by heating and rotary evaporation at 80 °C and 25 kPa. After regeneration, the ethanolamine adsorption capacity of the activated carbon fiber E modified with protonic acidic imidazole bis(trifluoromethanesulfonate) is 58%, and it can be completely restored.

[0062] Regenerate the activated carbon fiber E' modified with protonic acidic imidazole bis(trifluoromethanesulfonate) that is saturated with adsorption by heating and rotary evaporation at 80 °C and 25 kPa. After regeneration, the ethanolamine adsorption capacity of the activated carbon fiber E' modified with protonic acidic imidazole bis(trifluoromethanesulfonate) is 42%, and it can be completely restored.

[0063] Regenerate the activated carbon fiber e modified with protonic acidic imidazole bis(trifluoromethanesulfonate) that is saturated with adsorption by heating and rotary evaporation at 80 °C and 25 kPa. After regeneration, the ethanolamine adsorption capacity of the activated carbon fiber e modified with protonic acidic imidazole bis(trifluoromethanesulfonate) is 62%, and it can be completely restored.

[0064] Comparative Example 1

[0065] Add 20 g of ethanolamine to a 50 mL two-necked flask. Place the two-necked flask in a water bath at 40 °C and introduce nitrogen at a rate of 0.4 L / min. The gas passes over the ethanolamine liquid surface and does not pass below the liquid surface to simulate the exhaust gas from an absorption tower at a certain concentration. Continuously introduce the prepared simulated gas into another drying tube containing 2 g of activated carbon fiber A. Weigh it every 5 minutes. After 2 h, the weight of the drying tube containing the activated carbon fiber A no longer changes, and the ethanolamine adsorption capacity of the component of the activated carbon fiber A is 25%.

[0066] Comparing the examples and the comparative examples, it can be seen that the method for capturing and purifying the gaseous organic amine escaping after carbon dioxide removal from flue gas according to the present invention can replace the traditional water washing process, effectively reduce the concentration of the discharged organic amine, and recycle the high-concentration organic amine for reuse without generating wastewater discharge, effectively reducing costs, and having good application prospects in the field of post-treatment of carbon capture and separation.

Claims

1. An ionic liquid-modified activated carbon fiber, which is prepared by the following steps: 1) React an activated carbon fiber containing an active group with a substituted silane compound to obtain a silane-modified activated carbon fiber, wherein the substituted silane compound is a silane substituted by one or more substituents selected from halogen, halo-C 1～6 alkyl, C 1～6 alkyl, and C 1～6 alkoxy, and the substituted silane compound contains at least one halo-C 1～6 alkyl and at least one C 1～6 alkoxy; 2) React the silane-modified activated carbon fiber obtained in step 1) with a nitrogen-containing ionic liquid precursor, where, The precursor of the nitrogen-containing ionic liquid is selected from substituted or unsubstituted imidazole compounds, substituted or unsubstituted pyrrolidine compounds, quaternary amine compounds, substituted or unsubstituted pyridine compounds, substituted or unsubstituted piperidine compounds, substituted or unsubstituted piperazine compounds, and substituted or unsubstituted pyrrole compounds; 3) React the product obtained in step 2) with a salt solution containing one or more selected from Cl - 、Br - 、I - 、BF4 - 、PF6 - 、NO3 - 、ClO4 - 、HSO3 - 、HSO4 - 、H2PO4 - 、CH3COO - 、CH3(CH2) p COO - 、SCN - 、SbF6 - 、AsF6 - 、CF3 - 、CF3COO - 、CH3SO4 - 、C2H6SO4 - 、C8H 17 SO4 - 、C4F9SO3 - 、CF3(CF2) p SO3 - 、(CF3SO2)3C - 、(C2F5SO2)2N - 、(CF3SO2)2N - 、CH3CH(OH)COO - 、dodecyl sulfonate, benzenesulfonate, and p-toluenesulfonate to carry out an anion exchange reaction to obtain an ionic liquid-modified activated carbon fiber, where p is independently selected from integers from 0 to 12.

2. The ionic liquid-modified activated carbon fiber according to claim 1, wherein The precursor of the nitrogen-containing ionic liquid is one or more selected from the following compounds: Wherein, R1 and R2 are each independently H or -(CH2) n CH3, and at least one of them is -H, and n is an integer between 0 and 12; R3 to R9 are independently selected from -H, -(CH2) m CH3, -(CH2) m CH=CH2, and m are each independently an integer between 0 and 12.

3. The activated carbon fiber modified with ionic liquid according to claim 1 or 2, wherein, The substituted silane compound is selected from halo C 1～6 alkyl C 1～6 alkoxysilane, bis(halo C 1～6 alkyl)C 1～6 alkoxysilane, tris(halo C 1～6 alkyl)C 1～6 alkoxysilane, (halo C 1～6 alkyl)di(C 1～6 alkoxy)silane, (halo C 1～6 alkyl)tri(C 1～6 alkoxy)silane, bis(halo C 1～6 alkyl)di(C 1～6 alkoxy)silane, halo C 1～6 alkyl C 1～6 Alkoxyhalosilanes; more preferably selected from chloropropylmethoxysilane, bis(chloropropyl)methoxysilane, tris(chloropropyl)methoxysilane, chloropropyldimethoxysilane, bis(chloropropyl)dimethoxysilane, chloropropyltrimethoxysilane, chloropropylethoxysilane, bis(chloropropyl)ethoxysilane, tris(chloropropyl)ethoxysilane, chloropropyldiethoxysilane, bis(chloropropyl)diethoxysilane, chloropropyltriethoxysilane, chloropropylpropoxysilane, bis(chloropropyl)propoxysilane, tris(chloropropyl)propoxysilane, chloropropyldipropoxysilane, bis(chloropropyl)dipropoxysilane, chloropropyltripropoxysilane, chloropropylbutoxysilane, bis(chloropropyl)butoxysilane, tris(chloropropyl)butoxysilane, chloropropyldibutoxysilane, bis(chloropropyl)dibutoxysilane, chloropropyltributoxysilane, chlorobutylmethoxysilane, bis(chlorobutyl)methoxysilane, tris(chlorobutyl)methoxysilane, chlorobutyldimethoxysilane, bis(chlorobutyl)dimethoxysilane, chlorobutyltrimethoxysilane, chlorobutylethoxysilane, bis(chlorobutyl)ethoxysilane, tris(chlorobutyl)ethoxysilane, chlorobutyldiethoxysilane, bis(chlorobutyl)diethoxysilane, chlorobutyltriethoxysilane, chlorobutylpropoxysilane, chlorobutyldipropoxysilane, chlorobutyltripropoxysilane, chlorobutylbutoxysilane, bis(chlorobutyl)butoxysilane, tris(chlorobutyl)butoxysilane, chlorobutyldibutoxysilane, bis(chlorobutyl)dibutoxysilane, chlorobutyltributoxysilane, chloropentylmethoxysilane, bis(chloropentyl)methoxysilane, tris(chloropentyl)methoxysilane, chloropentyldimethoxysilane, bis(chloropentyl)dimethoxysilane, chloropentyltrimethoxysilane, chloropentylethoxysilane, bis(chloropentyl)ethoxysilane, tris(chloropentyl)ethoxysilane, chloropentyldiethoxysilane, bis(chloropentyl)diethoxysilane, chloropentyltriethoxysilane, chloropentylpropoxysilane, bis(chloropentyl)propoxysilane, tris(chloropentyl)propoxysilane, chloropentyldipropoxysilane, bis(chloropentyl)dipropoxysilane, chloropentyltripropoxysilane, chloropentylbutoxysilane, bis(chloropentyl)butoxysilane, tris(chloropentyl)butoxysilane, chloropentyldibutoxysilane, bis(chloropentyl)dibutoxysilane, chloropentyltributoxysilane, chlorohexylmethoxysilane, bis(chlorohexyl)methoxysilane, tris(chlorohexyl)methoxysilane, chlorohexyldimethoxysilane, bis(chlorohexyl)dimethoxysilane, chlorohexyltrimethoxysilane, chlorohexylethoxysilane, bis(chlorohexyl)ethoxysilane, tris(chlorohexyl)ethoxysilane, chlorohexyldiethoxysilane, bis(chlorohexyl)diethoxysilane, chlorohexyltriethoxysilane, chlorohexylpropoxysilane, bis(chlorohexyl)propoxysilane, tris(chlorohexyl)propoxysilane, chlorohexyldipropoxysilane, bis(chlorohexyl)dipropoxysilane, chlorohexyltripropoxysilane, chloroethylethoxysilane, bis(chloroethyl)ethoxysilane, tris(chloroethyl)ethoxysilane,Chloroethyl diethoxysilane, bis(chloroethyl)diethoxysilane, chloroethyl triethoxysilane, chloroethyl methoxysilane, bis(chloroethyl)methoxysilane, tris(chloroethyl)methoxysilane, chloroethyl dimethoxysilane, bis(chloroethyl)dimethoxysilane, chloroethyl trimethoxysilane, chloroethyl propoxysilane, bis(chloroethyl)propoxysilane, tris(chloroethyl)propoxysilane, chloroethyl dipropoxysilane, bis(chloroethyl)dipropoxysilane or chloroethyl tripropoxysilane, more preferably 3-chloropropyltriethoxysilane or 3-chlorohexyltriethoxysilane.

4. The ionic liquid-modified activated carbon fiber according to any one of claims 1 to 3, wherein, The weight ratio of the activated carbon fiber containing active groups to the substituted silane compound is 1:(0.01 - 1), preferably 1:(0.2 - 1), more preferably 1:(0.3 - 1); and / or The activated carbon fiber containing active groups is one or more selected from phenolic fibers, PAN-based fibers, viscose-based fibers, and pitch-based fibers; and / or The active groups on the activated carbon fiber containing active groups are one or more selected from hydroxyl groups, carboxyl groups, phenolic groups, quinone groups, sulfhydryl groups, nitrogen-containing groups, and halogens.

5. The ionic liquid-modified activated carbon fiber according to any one of claims 1 to 4, wherein The reaction conditions in step 1) are: cutting the activated carbon fiber A containing active groups into square pieces of 3 - 5 cm, placing the activated carbon fiber containing active groups in a flask, adding a solvent and a substituted silane compound, and reacting under nitrogen protection and reflux condensation conditions to obtain a modified activated carbon fiber; Preferably, the solvent used in step 1) is one or several selected from acetonitrile, ethanol, ethylene glycol, glycerol, propanol, isopropanol, n-butanol, isobutanol, pentanol, dimethyl ether, diethyl ether, dipropyl ether, dibutyl ether, methyl ethyl ether, ethyl propyl ether, propyl butyl ether, polyethylene glycol dimethyl ether, ethyl acetate, butyl acetate, N-methyl-2-pyrrolidone, 2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and sulfolane.

6. The ionic liquid-modified activated carbon fiber according to any one of claims 1 to 5, wherein The weight of the added nitrogen-containing ionic liquid precursor is 0.03 - 1 times, preferably 0.03 - 0.5 times, the weight of the activated carbon fiber containing active groups.

7. The ionic liquid-modified activated carbon fiber according to any one of claims 1 to 6, wherein The reaction conditions in step 2) are: mixing the silane-modified activated carbon fiber with the nitrogen-containing ionic liquid precursor in a solvent, and reacting under nitrogen protection and reflux condensation.

8. The ionic liquid-modified activated carbon fiber according to any one of claims 1 to 7, wherein, The concentration of the salt solution in step 3) is 0.01 - 5 mol / L; Preferably, the solvent in the salt solution in step 3) is water.

9. A method for trapping and purifying gaseous organic amines escaping after flue gas decarbonization, which comprises the following steps: a) Contacting the ionic liquid-modified activated carbon fiber according to any one of claims 1 to 8 with the gas after flue gas decarbonization purification; and / or The gas-phase organic phase is one or more selected from ammonia, ethanolamine, diethanolamine, triethanolamine, diisopropylamine, piperazine, hydroxyethyl ethylenediamine, N-methyldiethanolamine, 2-amino-2-methyl-1-propanol, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine; Preferably, the contact conditions in step a) are: gas-solid contact mode, and the temperature is 10-60 °C.

10. The method for capturing and purifying the gas-phase organic amine escaping after the flue gas decarbonization according to claim 9, further comprising the following steps: b) After the ionic liquid-modified activated carbon fiber is saturated by enrichment, the adsorbed organic amine is desorbed and regenerated by a thermal evaporation method to obtain an organic amine solution, and the regenerated ionic liquid-modified activated carbon fiber is then continued to be used for capturing the gas-phase organic amine. Preferably, the regeneration conditions in step b) are: 70-100 °C, 10-50 kPa absolute pressure.

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