A method for preparing carbon materials using anion exchange resin

Abstract

This application belongs to the field of porous carbon material preparation technology, specifically relating to a method for preparing carbon materials using anion exchange resin. The anion exchange resin is treated with an acidifying agent, then dried, and finally heated and carbonized in a gas atmosphere to obtain the carbon material. This application uses an acidifying agent pretreatment to convert basic groups into salt forms, suppressing the thermal decomposition pathway. When the acidified resin is carbonized in an inert atmosphere, the skeletal integrity is maintained, and the carbonization yield is improved, solving the problem of inefficient carbonization of anion exchange resins. Furthermore, this application only requires two steps: acidification pretreatment and carbonization, resulting in low energy consumption.

Description

Technical Field

[0001] This application belongs to the field of porous carbon material preparation technology, specifically relating to a method for preparing carbon materials using anion exchange resin. Background Technology

[0002] Ion exchange resins are materials that acquire ion exchange or adsorption capabilities by loading specific functional groups onto cross-linked polystyrene microspheres as a substrate. Due to their excellent performance, these materials have extremely wide applications in many fields such as water treatment and purification, industrial product purification, non-ferrous metallurgy, medical and pharmaceutical applications, and nuclear wastewater treatment. Statistics show that my country's annual production of ion exchange resins is approximately 370,000 tons. With the increasing usage, various industrial sectors also generate a large amount of waste ion exchange resins each year. If these waste resins are not properly treated, they not only occupy land resources but may also cause environmental pollution due to their organic matter and residual ions. Therefore, there is a significant technological need for how to effectively recycle and reuse these waste ion exchange resins to meet environmental protection requirements and achieve value regeneration. In the exploration of resource utilization technologies for waste ion exchange resins, converting them into high-value-added porous carbon materials is an important research direction.

[0003] For cation exchange resins prepared by sulfonation, the carbonization process is relatively direct. High-temperature carbonization under inert gas protection can inherit the resin's excellent spherical morphology and abundant pore structure, resulting in activated carbon spheres. Especially when using macroporous cation exchange resins as precursors, the resulting carbon materials often possess both microporous and mesoporous pore structures. This hierarchical porous material has already achieved industrial applications in hemodialysis materials and the adsorption and treatment of volatile organic compounds (VOCs). Furthermore, target metal ions (such as Zn) can be introduced before carbonization. 2+ Cu 2+ (etc.) are adsorbed onto the resin, and then carbonized to obtain a carbon-based catalytic material loaded with metal oxides, as described in patent CN202010693579.X.

[0004] For example, the technical solution with announcement number CN109896513A discloses a method for preparing ion exchange resin-based porous carbon materials. The specific steps of this method are: ion exchange resin (mainly cation exchange resin) is ion-exchanged with silicate; the silicate-containing ion exchange resin is pyrolyzed at high temperature to obtain a composite material of carbon and silica; the silica component in the composite material is removed, finally obtaining a carbon material with a high specific surface area. The problems with this technical solution are as follows: 1) After carbonization, silica and metal ions remain in the carbon material, making it difficult to completely wash away; 2) The carbonizability of anion exchange resin is extremely poor. Due to the presence of Hofmann elimination, the carbon yield of the resin is very low. Although the addition of silicate reduces the volatilization and loss of carbon in the form of organic matter, the carbon yield is still not high, and the resulting carbon spheres show severe shrinkage.

[0005] The technical solution disclosed in CN114620721A is a method for preparing weakly basic ion exchange resin-based carbon spheres. This method uses basic ion exchange resin as raw material, cross-links it with polychlorinated hydrocarbons (PCHs), and then carbonizes it under an inert atmosphere. Alternatively, physical activators such as water and carbon dioxide can be introduced to obtain activated carbon spheres. The problems with this technical solution are as follows: 1) It requires the use of PCHs, which have a certain degree of toxicity; 2) Long-chain PCHs are expensive and are decomposed and consumed during carbonization, making them unrecoverable and resulting in high costs.

[0006] Chinese invention patent CN114713193B discloses a nitrogen-doped magnetic porous carbon composite material, its preparation method, and its application. This technical solution uses an alkaline ion exchange resin as a raw material, which is reacted with ferrous sulfate and then heated for carbonization to finally obtain a nitrogen-doped carbon material. The problems with this technical solution are as follows: 1) The decomposition of ferrous sulfate produces highly toxic (CN)₂ gas; 2) There is no evidence that ferrous sulfate can prevent the Hoffmann elimination reaction, therefore the carbon yield of the product may be low.

[0007] The technical solution disclosed in CN116682673A is a method for the large-scale preparation of transition metal oxide-doped porous carbon as an electrode material for supercapacitors. This method uses various ion exchange resins as raw materials, Na2CO3, K2CO3, NaHCO3, and KHCO3 as pore-forming agents, and Fe... 3+ Co 2+ Ni 2+ Cr 3+ Mn 2+ The supercapacitor material is obtained by calcination using sulfates, chlorides, nitrates, bicarbonates, carbonates, citrates, tartrates, oxalates, acetates, or hydroxides as catalysts.

[0008] The problems with this technical solution are as follows: 1) The added alkali and salt remain in the carbon material, making it difficult to wash away completely; 2) Fe 3+ Co 2+ Ni 2+ Cr 3+ Mn 2+ The hydroxides are all insoluble and cannot be uniformly incorporated into the ion exchange resin; 3) Strongly acidic macroporous resins will break when they come into contact with alkaline solutions.

[0009] The technical solution disclosed in CN109534337A is a graphitized porous carbon material and its preparation method, electrode and its application. This technical solution also uses a salt solution to treat the resin, followed by carbonization by calcination under an inert gas, then calcination in a mixture of carbon dioxide and inert gas, and finally cleaning to obtain the carbon material. This technical solution has the following problems: 1) Using a salt solution as a treatment agent requires thorough washing of the final product, but carbon materials with high specific surface area are difficult to clean once they contain salt ions; 2) Carbon dioxide is added in the second heat treatment process, which is actually a physical activation process in which CO2 reacts with carbon to produce CO. However, this reaction requires temperatures above 900°C to occur, so if the second calcination is carried out at a low temperature, it will not improve the performance of the material.

[0010] Chinese invention patent CN105110330B discloses a method for preparing activated carbon material and its application. This technical solution selects three strong acid resins, one weak acid resin, and one chelating resin as raw materials. The process involves loading chloride and nitrate salts of Ca, Mg, Na, and K, or NaOH and KOH, followed by carbonization under nitrogen, pre-oxidation under air, and then carbonization again under nitrogen to obtain activated carbon material. The final material requires washing with HCl solution. This technical solution has the following problems: 1) Using alkali or salt agents as treatment agents requires thorough washing of the final product; 2) Macroporous strong acid resins will fracture when exposed to alkaline solutions or low-salinity water; 3) The resin calcination process is complex, requiring heat treatment under alternating atmospheres of N2, air, and N2 to achieve carbonization.

[0011] However, in stark contrast to the relatively mature carbonization technology of cation exchange resins, there are no reports of successful high-temperature carbonization of anion exchange resins (including strongly basic and weakly basic anion exchange resins) produced in large quantities in the industrial sector to prepare carbon materials. The fundamental reason is that anion exchange resins cannot be effectively carbonized using conventional methods like cation exchange resins. When anion exchange resins are carbonized at high temperatures under an inert atmosphere, severe volatilization and decomposition occur, releasing large amounts of gaseous organic compounds (such as amines and hydrocarbons), resulting in an extremely low yield of residual carbides, typically less than 2% of the raw material mass. These minimal residual carbides exhibit a heavily aggregated, loosely structured, vacuolated morphology with a very low specific surface area, possessing almost no industrial application value. This is due to the instability of the functional groups of anion exchange resins under heat and their destructive effect on the polystyrene skeleton. For strongly basic anion exchange resins, the functional groups are quaternary ammonium groups. During heating, especially after reaching a certain temperature, quaternary ammonium groups readily undergo Hofmann elimination reactions. This reaction eliminates an organic amine molecule, producing a tertiary amine and an alkene. This elimination reaction directly disrupts the benzene ring structure linked to the quaternary ammonium group, causing the polystyrene crosslinking backbone to break and disintegrate at that position (as shown in the attached image). Figure 26 (This is a diagram illustrating the organic chain disintegration mechanism during the carbonization of common strong-base resins). The disintegration of the skeleton significantly reduces the likelihood of subsequent formation of a stable carbon structure. For weakly basic anion exchange resins, their functional groups are primary, secondary, or tertiary amines. These amine groups also exhibit low thermal stability, beginning to decompose at relatively low temperatures, releasing ammonia or corresponding amines and small molecules such as olefins. These decomposition products not only evaporate and are lost, but their decomposition process also disturbs or even destroys the adjacent benzene ring structure, weakening the stability of the crosslinking network. Ultimately, this leads to increased fragmentation of the entire resin skeleton during high-temperature carbonization, preventing the formation of an effective carbon skeleton.

[0012] In summary, finding a way to carbonize anion exchange resin into carbon materials with high specific surface area is of great significance for the resource utilization of large quantities of waste anion exchange resin. Summary of the Invention

[0013] To address the problem of direct high-temperature carbonization of anion exchange resins in existing technologies, this application uses an acidifying agent to neutralize and acidify the anion exchange resin, followed by carbonization in an inert gas to obtain a carbon material with a high specific surface area. With a reasonable amount of acidifying agent, the morphology and quality yield of the product can be guaranteed, providing a reliable solution for the carbonization of waste anion exchange resins.

[0014] The technical solution of this application is as follows:

[0015] A method for preparing carbon materials using anion exchange resin involves treating the anion exchange resin with an acidifying agent, drying the acidified anion exchange resin, and finally heating and carbonizing the dried anion exchange resin in a gaseous atmosphere to obtain the carbon material.

[0016] Preferably, the acidifying agent is any one or a mixture of any proportion of sulfuric acid, aminosulfonic acid, and chlorosulfonic acid.

[0017] Preferably, the anion exchange resin is any one of macroporous strong-base anion exchange resin, macroporous weak-base anion exchange resin, or gel-type strong-base anion exchange resin.

[0018] Preferably, when the anion exchange resin is a macroporous strong base anion exchange resin or a gel-type strong base anion exchange resin, the ratio of the amount of hydrogen ions provided by the acidifying agent to the amount of basic groups in the macroporous strong base anion exchange resin or the gel-type strong base anion exchange resin is 7:1 to 1.5:1.

[0019] Preferably, when the anion exchange resin is a macroporous strong base anion exchange resin or a gel-type strong base anion exchange resin, the ratio of the amount of hydrogen ions provided by the acidifying agent to the amount of basic groups in the macroporous strong base anion exchange resin or the gel-type strong base anion exchange resin is 5:1 to 1.5:1.

[0020] Preferably, when the anion exchange resin is a macroporous weakly basic anion exchange resin, the ratio of the amount of hydrogen ions provided by the acidifying agent to the amount of basic groups in the macroporous weakly basic anion exchange resin is 9:1 to 1.5:1.

[0021] Preferably, when the anion exchange resin is a macroporous weakly basic anion exchange resin, the ratio of the amount of hydrogen ions provided by the acidifying agent to the amount of basic groups in the macroporous weakly basic anion exchange resin is 6:1 to 2:1.

[0022] Preferably, the carbonization heat treatment temperature of the acidified anion exchange resin is 500~900℃, the heating rate is 2℃ / min~10℃ / min, and the carbonization time is 2hr~10hr.

[0023] Preferably, the heating rate is 5℃ / min.

[0024] Preferably, the carbonization heat treatment gas atmosphere of the acidified anion exchange resin is any one or a mixture of any proportion of nitrogen, argon, water vapor, and carbon dioxide.

[0025] The beneficial effects of this application are as follows:

[0026] This application utilizes an acidifying agent pretreatment. During carbonization in an inert atmosphere after acidification, the integrity of the resin skeleton is maintained, resulting in improved carbonization yield and overcoming the technical bottleneck of inefficient carbonization of anion exchange resins. This application requires only two steps: acidification pretreatment and carbonization, thus consuming less energy. Attached Figure Description

[0027] Figure 1 This is a scanning electron microscope image of the carbon material obtained in Example 1;

[0028] Figure 2 This is a scanning electron microscope image of the carbon material obtained in Example 2;

[0029] Figure 3 This is a scanning electron microscope image of the carbon material obtained in Example 3;

[0030] Figure 4 This is a scanning electron microscope image of the carbon material obtained in Example 4;

[0031] Figure 5 This is a scanning electron microscope image of the carbon material obtained in Example 5;

[0032] Figure 6 This is a scanning electron microscope image of the carbon material obtained in Example 6;

[0033] Figure 7 This is a scanning electron microscope image of the carbon material obtained in Example 7;

[0034] Figure 8 This is a scanning electron microscope image of the carbon material obtained in Example 8;

[0035] Figure 9 This is a scanning electron microscope image of the carbon material obtained in Example 11;

[0036] Figure 10 This is a scanning electron microscope image of the carbon material obtained in Example 12;

[0037] Figure 11 This is a scanning electron microscope image of the carbon material obtained in Example 13;

[0038] Figure 12 This is a scanning electron microscope image of the carbon material obtained in Example 14;

[0039] Figure 13 This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 1;

[0040] Figure 14 This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 2;

[0041] Figure 15This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 3;

[0042] Figure 16 This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 4;

[0043] Figure 17 This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 5;

[0044] Figure 18 This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 6;

[0045] Figure 19 This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 7;

[0046] Figure 20 This is a micropore distribution diagram (MD method) of the carbon material obtained in Example 8;

[0047] Figure 21 This is a micropore distribution diagram of the carbon material obtained in Example 11 (Harkins-Jura absolute method).

[0048] Figure 22 This is a micropore distribution diagram of the carbon material obtained in Example 12 (Harkins-Jura absolute method).

[0049] Figure 23 This is a micropore distribution diagram of the carbon material obtained in Example 13 (Harkins-Jura absolute method).

[0050] Figure 24 This is a micropore distribution diagram of the carbon material obtained in Example 14 (Harkins-Jura absolute method).

[0051] Figure 25 This is a flowchart of the technical solution of this application;

[0052] Figure 26 This diagram illustrates the organic chain disintegration mechanism during the carbonization of common strong alkali resins.

[0053] Figure 27 This is a schematic diagram of the carbonization process of strong base resin involving sulfuric acid. Detailed Implementation

[0054] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0055] After reviewing a large amount of technical literature, the applicant found no simple and easy method to obtain spherical activated carbon materials from basic ion exchange resins. Furthermore, it is generally understood in the art that direct carbonization of ordinary strong basic resins would destroy the benzene ring structure, rendering them unusable. Sulfonation methods may result in low carbon material yields and complicated post-carbonization processing. The applicant, however, discovered that by acidifying and carbonizing basic ion exchange resins with sulfuric acid, chlorosulfonic acid, or aminosulfonic acid, they were able to obtain structurally intact carbon materials with a high yield.

[0056] Example 1

[0057] This embodiment provides a method for preparing carbon materials using sulfuric acid solution as an acidifying agent based on macroporous strong base anion exchange resin. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0058] Step S1. Weigh 100g of fully dried macroporous strong base anion exchange resin with a saturated absorption liquid volume of 110mL. Prepare 110mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 7 times the exchange capacity of the basic groups of the resin. Immerse the resin in the acidifying agent until the acidifying agent is completely absorbed. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0059] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heating to 800℃, holding for carbonization for 4h, cooling to 250℃ under nitrogen atmosphere and then opening the furnace to obtain 50.5g of carbon material.

[0060] Performance testing: The particle morphology was tested using scanning electron microscopy, as shown in the attached figure. Figure 1 As shown in the figure, scanning electron microscopy reveals that the prepared carbon spheres are broken carbon spheres, possibly due to a large amount of acidifying agent. The pore distribution curve was determined using the MD method as shown in the figure. Figure 13 As shown, its specific surface area, measured by nitrogen adsorption, is 843.5 m². 2 / g, pore volume is 0.331mL / g, average pore size is 1.58nm, mass yield is about 50%, and sulfur content of the sample measured by EDX method is 2.49wt%.

[0061] Example 2

[0062] This embodiment provides a method for preparing carbon materials based on macroporous strong-base anion exchange resin using chlorosulfonic acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0063] Step S1. Weigh 500g of fully dried macroporous strong base anion exchange resin with a saturated absorption liquid volume of 550mL. Prepare 550mL of chlorosulfonic acid solution as an acidifying agent, wherein the hydrogen ion content of chlorosulfonic acid is 5 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 110℃.

[0064] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with argon gas, heating at a rate of 10℃ / min, heating to 900℃, holding at that temperature for 2 hours, cooling the argon atmosphere to 250℃ and then opening the furnace to obtain 219.6g of carbon material.

[0065] Performance testing:

[0066] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 2 As shown in the figure, scanning electron microscopy reveals that the prepared carbon spheres have good morphology, which may be due to the appropriate amount of acid used; the pore distribution curve measured by MD method is shown in the figure. Figure 14 As shown, its specific surface area, measured by nitrogen adsorption, is 930.8 m². 2 / g, pore volume is 0.434mL / g, average pore size is 1.86nm, mass yield is about 44.8%, and sulfur content of the sample determined by EDX method is 2.12wt%.

[0067] Example 3

[0068] This embodiment provides a method for preparing carbon materials based on macroporous strong base anion exchange resin using aminosulfonic acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0069] Step S1. Weigh 1000g of fully dried macroporous strong base anion exchange resin with a saturated absorption liquid volume of 1150mL. Prepare 1150mL of aminosulfonic acid solution as an acidifying agent, wherein the hydrogen ion content of aminosulfonic acid is 3 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 130℃.

[0070] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with carbon dioxide gas, heating rate 2℃ / min, heating to 500℃, holding for carbonization for 10h, cooling the carbon dioxide atmosphere to 250℃ and then opening the furnace to obtain 380.4g of carbon material.

[0071] Performance testing:

[0072] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 3 As shown in the figure, scanning electron microscopy reveals that the prepared carbon spheres have good morphology, which is due to the appropriate amount of acidifying agent. The pore distribution curve was tested using the MD method as shown in the figure. Figure 15As shown, its specific surface area, measured by nitrogen adsorption, is 769.5 m². 2 The pore volume is 0.496 mL / g, the average pore size is 2.58 nm, so the obtained carbon material is a carbon ball with good morphology, and the mass yield is about 38%. The sulfur content of the sample measured by EDX method is 2.15 wt%. It can also be seen that the less acidifying agent used, the smaller the diameter of the obtained carbon ball.

[0073] Example 4

[0074] This embodiment provides a method for preparing carbon materials based on macroporous strong base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0075] Step S1. Weigh 200g of fully dried macroporous strong base anion exchange resin with a saturated absorption liquid volume of 221mL. Prepare 221mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 1.5 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0076] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with water vapor in the atmosphere. The heating rate is 5℃ / min. The temperature is raised to 600℃ and carbonized for 4 hours. After the water vapor atmosphere is cooled to 250℃, the furnace is opened to obtain 56.3g of carbon material.

[0077] Performance testing:

[0078] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 4 As shown in the figure, scanning electron microscopy reveals that the prepared carbon spheres have a small diameter, which is due to the small amount of acidifying agent used; the pore distribution curve measured by the MD method is shown in the figure. Figure 16 As shown, its specific surface area, measured by nitrogen adsorption, is 552.4 m². 2 / g, pore volume is 0.21mL / g, average pore size is 1.56nm, mass yield is about 28%, and sulfur content of the sample determined by EDX method is 2.03wt%.

[0079] Examples 1-4 were conducted on macroporous strong-base anion exchange resins. It was found that within the scope of this application, macroporous strong-base anion exchange resins can be effectively treated to obtain carbon materials. When the basic ion exchange resin is acidified and treated with sulfuric acid, chlorosulfonic acid, or aminosulfonic acid, its quaternary ammonium, tertiary amine, secondary amine, and primary amine are neutralized with sulfate and other acid radicals to form salts. Excess acid beyond the neutralization stoichiometry is likely adsorbed into the resin pores. During the subsequent carbonization process, due to the increased temperature, the strong-base resin undergoes Hofmann elimination, and its quaternary ammonium cation decomposes into trimethylamine and is instantly lost. The sulfate or hydrogen sulfate ions that are in charge balance with it may first attack the methylene group attached to the quaternary ammonium group, temporarily forming a sulfate ester, and then continue to attack the benzene ring originally attached to the quaternary ammonium group, leading to rapid carbonization of the benzene ring and thus avoiding the rupture and decomposition of the benzene ring (the participation of sulfuric acid in the carbonization process of strong-base resins is shown in the attached figure). Figure 27 As shown in the figure, this greatly improves the quality yield of carbonization products. In addition, the acid with a higher stoichiometric number than the neutralization stoichiometry may also play a role in sulfonating the benzene ring while the quaternary ammonium ion is lost, thus protecting the integrity of the benzene ring structure and further carbonization.

[0080] Example 5

[0081] This embodiment provides a method for preparing carbon materials based on macroporous weak base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0082] Step S1. Weigh 1000g of fully dried macroporous weak base anion exchange resin with a saturated absorption liquid volume of 2100mL. Prepare 2100mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 9 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0083] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heating to 800℃, holding for carbonization for 4h, cooling to 250℃ under nitrogen atmosphere and then opening the furnace to obtain 621.4g of carbon material.

[0084] Performance testing:

[0085] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 5 As shown, scanning electron microscopy reveals surface damage to the prepared carbon spheres, which may be due to the large amount of acidifying agent used. The pore distribution curve was tested using the MD method as shown in the figure. Figure 17 As shown, its specific surface area, measured by nitrogen adsorption, is 933.04 m². 2 / g, pore volume is 0.359mL / g, average pore size is 1.54nm, mass yield is about 62%, and sulfur content of the sample determined by EDX method is 2.89wt%.

[0086] Example 6

[0087] This embodiment provides a method for preparing carbon materials based on macroporous weak base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0088] Step S1. Weigh 1000g of fully dried macroporous weak base anion exchange resin with a saturated absorption liquid volume of 2000mL. Prepare 2000mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 6 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0089] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heating to 700℃, holding for carbonization for 6h, cooling to 250℃ in nitrogen atmosphere and then opening the furnace to obtain 600.5g of carbon material.

[0090] Performance testing:

[0091] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 6 As shown in the figure, scanning electron microscopy reveals that the prepared carbon spheres have good morphology, which may be due to the appropriate acidifying agent. The pore distribution curve was measured using the MD method as shown in the figure. Figure 18 As shown, its specific surface area, measured by nitrogen adsorption, is 777.7 m². 2 / g, pore volume is 0.301mL / g, average pore size is 1.54nm, mass yield is about 60%, and sulfur content of the sample measured by EDX method is 2.71wt%.

[0092] Example 7

[0093] This embodiment provides a method for preparing carbon materials based on macroporous weak base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0094] Step S1. Weigh 1000g of fully dried macroporous weak base anion exchange resin with a saturated absorption liquid volume of 2100mL. Prepare 2100mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 4 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0095] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with argon gas, heating at a rate of 5°C / min until it reaches 600°C. Hold the temperature for 8 hours and then cool down to 250°C in the argon atmosphere before opening the furnace to obtain 535g of carbon material.

[0096] Performance testing:

[0097] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 7 As shown, scanning electron microscopy reveals surface damage to the prepared carbon spheres, which may be due to the large amount of acidifying agent used. The pore distribution curve was tested using the MD method as shown in the figure. Figure 19 As shown, its specific surface area, measured by nitrogen adsorption, is 729.6. 2 / g, pore volume is 0.38mL / g, average pore size is 2.1nm, mass yield is about 53%, and sulfur content of the sample determined by EDX method is 2.02wt%.

[0098] Example 8

[0099] This embodiment provides a method for preparing carbon materials based on macroporous weak base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0100] Step S1. Weigh 1000g of fully dried macroporous weak base anion exchange resin with a saturated absorption liquid volume of 2100mL. Prepare 2100mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 1.5 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0101] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heating to 600℃, holding for carbonization for 8h, cooling to 250℃ under nitrogen atmosphere and then opening the furnace to obtain 366.3g of carbon material.

[0102] Performance testing:

[0103] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 8 As shown in the figure, scanning electron microscopy reveals that the prepared carbon spheres have a small diameter, which may be due to the small amount of acidifying agent used; the pore distribution curve was tested using the MD method as shown in the figure. Figure 20 As shown, its specific surface area, measured by nitrogen adsorption, is 876.05 m². 2 / g, pore volume is 0.386mL / g, average pore size is 1.76nm, mass yield is about 36.6%, and sulfur content of the sample determined by EDX method is 1.78wt%.

[0104] Example 9

[0105] This embodiment provides a method for preparing carbon materials based on macroporous weak base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0106] Step S1. Weigh 1000g of fully dried macroporous weak base anion exchange resin with a saturated absorption liquid volume of 1980mL. Prepare 1980mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 4.5 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0107] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heating to 600℃, holding for carbonization for 8h, cooling to 250℃ under nitrogen atmosphere and then opening the furnace to obtain 437.5g of carbon material.

[0108] Performance testing:

[0109] Its specific surface area was determined to be 913.7 m² using the nitrogen adsorption method. 2 / g, pore volume is 0.235mL / g, average pore size is 1.03nm, mass yield is about 43.7%, and sulfur content of the sample determined by EDX method is 1.97wt%.

[0110] Example 10

[0111] This embodiment provides a method for preparing carbon materials based on macroporous weak base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0112] Step S1. Weigh 1000g of fully dried macroporous weak base anion exchange resin with a saturated absorption liquid volume of 2150mL. Prepare 2150mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 5 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0113] Step S2. The acidified and dried resin is carbonized in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heated to 700℃, held at this temperature for 6h, cooled to 250℃ under nitrogen atmosphere and then the furnace is opened to obtain 546.2g of carbon material.

[0114] Performance testing:

[0115] Its specific surface area was determined to be 875.6 m² using the nitrogen adsorption method. 2 / g, pore volume is 0.265mL / g, average pore size is 1.21nm, mass yield is about 54.6%, and sulfur content of the sample determined by EDX method is 2.09wt%.

[0116] Examples 5 to 10 conducted experiments on macroporous weak base anion exchange resins and found that within the scope of protection of this application, macroporous weak base anion exchange resins can be effectively processed to obtain carbon materials.

[0117] Example 11

[0118] This embodiment provides a method for preparing carbon materials based on a gel-type strong base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0119] Step S1. Weigh 1000g of fully dried gel-type strong base anion exchange resin with a saturated absorption liquid volume of 1350mL. Prepare 1350mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 7 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 110℃.

[0120] Step S2. Carbonize the acidified and dried resin in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heating to 800℃, holding for carbonization for 3h, cooling to 250℃ in nitrogen atmosphere and then opening the furnace to obtain 650.3g of carbon material.

[0121] Performance testing:

[0122] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 9 As shown in the figure, scanning electron microscopy reveals that the prepared carbon spheres have poor sphericity and contain amorphous aggregated particles, which may be due to the large amount of acidifying agent used. The pore distribution curve of the micropores was calculated using the Harkins-Jura absolute method, as shown in the figure. Figure 21 As shown, its pores are mainly micropores of 1-2 nm, with a relatively narrow pore size distribution. Its specific surface area, measured by nitrogen adsorption, is 573.3 m². 2 / g, pore volume is 0.248mL / g, average pore size is 1.73 nm, mass yield is about 65.03%, and sulfur content of the sample determined by EDX method is 2.57wt%.

[0123] Example 12

[0124] This embodiment provides a method for preparing carbon materials based on a gel-type strong base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0125] Step S1. Weigh 1000g of fully dried gel-type strong base anion exchange resin with a saturated absorption liquid volume of 1350mL. Prepare 1350mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 5 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 100℃.

[0126] Step S2. The acidified and dried resin is carbonized in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heated to 800℃, held at this temperature for 4h, cooled to 250℃ under nitrogen atmosphere and then the furnace is opened to obtain 571.0 g of carbon material.

[0127] Performance testing:

[0128] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 10 As shown in the scanning electron microscope, the prepared carbon spheres exhibit good sphericity, with particle diameters slightly smaller than those in Example 11. This may be due to the relatively reasonable amount of acidifying agent used. The pore distribution curve of the micropores was calculated using the Harkins-Jura absolute method, as shown in the figure. Figure 22 As shown, the material exhibits a very wide pore distribution, primarily mesoporous, with the most probable channels ranging from 5 to 8 nm. Its specific surface area, measured by nitrogen adsorption, is 436.0 m². 2 / g, pore volume is 0.184 mL / g, average pore size is 1.68 nm, mass yield is about 57.1%, and sulfur content of the sample determined by EDX method is 2.24 wt%.

[0129] Example 13

[0130] This embodiment provides a method for preparing carbon materials based on a gel-type strong base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0131] Step S1. Weigh 1000g of fully dried gel-type strong base anion exchange resin with a saturated absorption liquid volume of 1350mL. Prepare 1350mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 3 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 110℃.

[0132] Step S2. The acidified and dried resin is carbonized in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heated to 900℃, held at the temperature for 2h, cooled to 250℃ in nitrogen atmosphere and then the furnace is opened to obtain 488.6 g of carbon material.

[0133] Performance testing:

[0134] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 11As shown in the image, scanning electron microscopy reveals that the prepared carbon spheres have good sphericity, but some particles are broken, which may be due to the relatively low amount of acidifying agent. The pore distribution curve of the micropores was calculated using the Harkins-Jura absolute method, as shown in the image. Figure 23 As shown, the material exhibits a very wide pore distribution, primarily mesoporous, with the most probable channels ranging from 3 to 7 nm. Its specific surface area, measured by nitrogen adsorption, is 255.4 m². 2 / g, pore volume is 0.113 mL / g, average pore size is 1.75 nm, mass yield is about 48.86%, and sulfur content of the sample determined by EDX method is 1.93 wt%.

[0135] Example 14

[0136] This embodiment provides a method for preparing carbon materials based on a gel-type strong base anion exchange resin using sulfuric acid solution as an acidifying agent. The technical solution flow of this application is as follows: Figure 25 The details are as follows:

[0137] Step S1. Weigh 1000g of fully dried gel-type strong base anion exchange resin with a saturated absorption liquid volume of 1350mL. Prepare 1350mL of sulfuric acid solution as an acidifying agent, wherein the hydrogen ion content of the sulfuric acid is 1.5 times the exchange capacity of the basic groups of the resin. After the resin has absorbed the acidifying agent, dry it thoroughly at 110℃.

[0138] Step S2. The acidified and dried resin is carbonized in an atmosphere furnace with nitrogen atmosphere, heating rate 5℃ / min, heated to 800℃, held at this temperature for 3h, cooled to 250℃ under nitrogen atmosphere and then the furnace is opened to obtain 288.4 g of carbon material.

[0139] Performance testing:

[0140] The particle morphology was analyzed by scanning electron microscopy, as shown in the attached figure. Figure 12 As shown in the image, scanning electron microscopy reveals that most of the prepared carbon spheres exhibit longitudinal cracks. The cross-sections of the fractured particles show a distinct hollow structure inside. This is likely due to insufficient acidifier dosage, resulting in weak protection of the gel spheres and causing a large amount of polystyrene chains to disintegrate and volatilize, leading to a hollow structure and low yield in the final product. The pore size distribution curve of the micropores was calculated using the Harkins-Jura absolute method, as shown in the image. Figure 24 As shown, the material exhibits a very wide pore distribution, primarily mesoporous, with the most probable channels ranging from 4 to 8 nm. Its specific surface area, measured by nitrogen adsorption, is 174.9 m². 2 / g, pore volume is 0.091 mL / g, average pore size is 2.05 nm, mass yield is about 28.84%, and sulfur content of the sample determined by EDX method is 1.41 wt%.

[0141] Examples 11-14 conducted experiments on gel-type strong base anion exchange resins and found that gel-type strong base anion exchange resins could also achieve carbonization after acidification. However, compared with macroporous strong base anion exchange resins and macroporous weak base anion exchange resins, the carbon material obtained after acidification and carbonization of gel-type strong base anion exchange resins had a relatively low specific surface area, and the sphericity and integrity of the particles were relatively poor. This is likely because gel-type strong base anion exchange resins lack internal pores, making it difficult for the acidifying agent to diffuse within the particles. It is also difficult to protect the adjacent methylene and benzene rings after the quaternary ammonium groups disintegrate. Therefore, the specific surface area, pore volume, and particle sphericity of its carbonization products are all poor.

[0142] Comparative Example 1

[0143] In this comparative example, macroporous strong-base anion exchange resin was used as the raw material for preparing carbon material. The ion exchange resin was not acidified and was directly subjected to high-temperature carbonization: 100g of fully dried macroporous strong-base anion exchange resin was taken and carbonized directly in an atmosphere furnace with argon gas. The heating rate was 5℃ / min, and the temperature was raised to 700℃. The carbonization was carried out at this temperature for 6 hours. After cooling to 250℃ in the argon atmosphere, the furnace was opened, and 1.4g of carbon material was obtained. The sample was in the form of cavitation bubbles that were stuck together, easily broken, and had no strength.

[0144] Comparative Example 2

[0145] This comparative example uses gel-type strong base anion exchange resin as the raw material for preparing carbon material. The ion exchange resin was not acidified and was directly subjected to high-temperature carbonization: 100g of fully dried gel-type strong base anion exchange resin was taken and carbonized directly in an atmosphere furnace with argon atmosphere. The heating rate was 5℃ / min, the temperature was raised to 700℃, and carbonized at that temperature for 6 hours. After cooling to 250℃ in the argon atmosphere, the furnace was opened, and 2.0g of carbon material was obtained. The sample was agglomerated into a hollow plate shape, which was easy to break and had no strength.

[0146] In summary, this application, through acidifying agent pretreatment, ensures the integrity of the resin skeleton during carbonization in an inert atmosphere after acidification, thereby improving the carbonization yield and overcoming the technical bottleneck of inefficient carbonization of anion exchange resins. This application requires only two steps: acidification pretreatment and carbonization, resulting in low energy consumption.

[0147] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing carbon materials using anion exchange resin, characterized in that, Anion exchange resin is treated with an acidifying agent, then the acidified anion exchange resin is dried, and finally the dried anion exchange resin is heated and carbonized in a gas atmosphere to obtain carbon material. The acidifying agent is any one or more of sulfuric acid, aminosulfonic acid, and chlorosulfonic acid; The anion exchange resin is any one of macroporous strong-base anion exchange resin, macroporous weak-base anion exchange resin, or gel-type strong-base anion exchange resin.

2. The method for preparing carbon materials using anion exchange resin according to claim 1, characterized in that, When the anion exchange resin is a macroporous strong base anion exchange resin or a gel-type strong base anion exchange resin, the ratio of the amount of hydrogen ions provided by the acidifying agent to the amount of basic groups in the macroporous strong base anion exchange resin or the gel-type strong base anion exchange resin is 7:1 to 1.5:

1.

3. The method for preparing carbon materials using anion exchange resin according to claim 1, characterized in that, When the anion exchange resin is a macroporous weakly basic anion exchange resin, the ratio of the amount of hydrogen ions provided by the acidifying agent to the amount of basic groups in the macroporous weakly basic anion exchange resin is 9:1 to 1.5:

1.

4. The method for preparing carbon materials using anion exchange resin according to claim 1, characterized in that, The carbonization heat treatment temperature of the acidified anion exchange resin is 500~900℃, the heating rate is 2℃ / min~10℃ / min, and the carbonization time is 2hr~10hr.

5. The method for preparing carbon materials using anion exchange resin according to claim 1, characterized in that, The drying temperature is 100℃~130℃.

6. The method for preparing carbon materials using anion exchange resin according to claim 1, characterized in that, The carbonization heat treatment gas atmosphere of the acidified anion exchange resin is any one or any mixture of several of nitrogen, argon, water vapor, and carbon dioxide in any proportion.

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