A carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization and its preparation method

Abstract

The application discloses a carbon material for removing organic sulfur based on ion cross-linking-radical copolymerization and a preparation method thereof, and relates to the technical field of carbon material preparation. 2+ Sodium alginate, a vinyl monomer and a polystyrene-polyether type amphiphilic block copolymer are synchronously reacted to construct a high-molecular-weight double-network interpenetrating structure formed by ion cross-linking and radical copolymerization. Acrylamide and acrylic acid copolymer are used as an internal nitrogen source, and NH3 is introduced as an external nitrogen source for nitrogen doping in the carbonization process, so that a hierarchical nitrogen-doped structure rich in pyridine N and graphite N is realized. The carbon material with high desulfurization performance is produced by optimizing raw material selection, improving the preparation process and surface modification technology. The method has low production cost, excellent desulfurization effect, and can realize efficient and economic removal of organic sulfur in the natural gas purification process.

Description

Technical Field

[0001] This invention relates to the field of carbon material preparation technology, specifically to a carbon material and its preparation method based on ion crosslinking-free radical copolymerization for the removal of organic sulfur. Background Technology

[0002] With the continuous growth of global energy demand, natural gas, as a clean energy source, has become an important energy source. However, natural gas typically contains a certain amount of organic sulfides (such as carbonyl sulfide and methanethiol). These organic sulfides not only affect the quality of natural gas but also generate sulfur dioxide during combustion, causing environmental problems such as air pollution and acid rain. Therefore, effectively removing organic sulfur from natural gas has become an important research direction in current gas treatment technologies.

[0003] Currently, methods for removing organic sulfur compounds mainly include physical adsorption, chemical adsorption, and catalytic methods. Among these, adsorption methods have received widespread attention due to their simplicity and low cost. Adsorption materials typically include metal oxides, molecular sieves, activated carbon, and some modified carbon materials. However, conventional adsorption materials have some limitations in treating organic sulfur compounds in natural gas, such as low adsorption capacity, difficulty in regeneration, and short service life.

[0004] To overcome these shortcomings, carbon materials, as adsorption media with high specific surface area, tunable pore structure, and excellent chemical stability, have become an important research direction in desulfurization technology. In recent years, researchers have aimed to improve the adsorption capacity and catalytic performance of carbon materials for organic sulfur by adjusting their preparation processes and modification methods. Carbon materials such as activated carbon, graphene, and carbon nanotubes have shown good application potential in the removal of organic sulfur; however, existing carbon material preparation methods still have some problems, such as high preparation costs and complex production processes.

[0005] This shows that the existing technology needs further improvement. Summary of the Invention

[0006] One objective of this invention is to provide a method for preparing carbon materials for removing organic sulfur based on ion crosslinking-free radical copolymerization. By optimizing raw material selection, improving the preparation process, and surface modification techniques, a carbon material with highly efficient desulfurization performance is produced. This method has low production costs, excellent desulfurization effect, and can achieve efficient and economical removal of organic sulfur during natural gas purification.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0009] a. Dissolve sodium alginate to obtain a sodium alginate solution, and then add polystyrene-polyether amphiphilic block copolymer, a copolymer of acrylamide and acrylic acid, an initiator, and ferrous ions to the sodium alginate solution in sequence to form a homogeneous solution;

[0010] b. Add CaCl2 solution dropwise to the homogeneous solution and raise the temperature to trigger the decomposition of the initiator, so that the polystyrene-polyether type amphiphilic block copolymer and the copolymer of acrylamide and acrylic acid undergo free radical copolymerization to form a hydrogel precursor. The hydrogel precursor has a hydrophobic-hydrophilic alternating double network interpenetrating structure.

[0011] c. The hydrogel precursor is immersed in a metal salt solution, so that the metal ions are uniformly dispersed and anchored in the double-network interpenetrating structure of the hydrogel precursor.

[0012] d. The sample obtained in step c is subjected to vacuum freeze-drying; then NH3 is introduced for high-temperature carbonization. NH3 provides exogenous nitrogen doping and combines with the copolymer of acrylamide and acrylic acid, which serves as the built-in nitrogen source in the hydrogel precursor, to obtain a carbon material with a hierarchical nitrogen-doped structure.

[0013] The beneficial technical effects directly brought about by the above technical solution are as follows:

[0014] This technical solution utilizes Ca 2+ Sodium alginate was simultaneously reacted with vinyl monomers and polystyrene-polyether amphiphilic block copolymers to construct a high-molecular-weight double-network interpenetrating structure formed by ionic crosslinking and free radical copolymerization. Acrylamide and acrylic acid copolymers were used as internal nitrogen sources, and NH3 was introduced as exogenous nitrogen dopant during the carbonization process, achieving a hierarchical nitrogen-doped structure rich in pyridine N and graphitic N. The epoxy groups in the amphiphilic block copolymers react with the amino groups in the vinyl monomer acrylamide, the amino groups in the acrylic acid copolymer, and the carboxylic acid groups in sodium alginate to generate hydroxyl groups, providing a strongly alkaline environment for the removal of organic sulfur. This material possesses high specific surface area, hierarchical pores, and uniform distribution of Cu-N active sites, exhibiting excellent adsorption and catalytic synergistic efficiency in organic sulfur removal. Its preparation process innovatively combines biomass templates, controlled polymerization, and hierarchical nitrogen doping technology, realizing the development of low-cost, environmentally friendly, and scalable carbon-based functional materials, providing a novel solution for the efficient removal of organic sulfur.

[0015] In the above-mentioned method for preparing carbon materials based on ion crosslinking-free radical copolymerization to remove organic sulfur, in step a, sodium alginate is dispersed in a mixed solution of deionized water and ethanol, and the temperature is controlled at 50-70℃ and stirred for 1-3 hours to dissolve it.

[0016] In the above-mentioned method for preparing a carbon material based on ion crosslinking-free radical copolymerization for removing organic sulfur, in step a, the polystyrene-polyether type amphiphilic block copolymer is polystyrene-polyethylene glycol, polystyrene-polyethylene oxide, or polystyrene-b-polyoxyethylene glycidyl acrylate; and the initiator is a peroxide initiator.

[0017] The above-mentioned method for preparing carbon materials based on ion crosslinking-free radical copolymerization for removing organic sulfur, wherein the polystyrene-polyether type amphiphilic block copolymer is polystyrene-b-polyoxyethylene glycidyl acrylate; and the initiator is hydrogen peroxide.

[0018] In the above-mentioned method for preparing a carbon material based on ion crosslinking-free radical copolymerization for removing organic sulfur, in step a, the mass ratio of polystyrene-polyether amphiphilic block copolymer to sodium alginate is 0.3-1:2.5-3.2; the mass ratio of acrylamide-acrylic acid copolymer to sodium alginate is 1.5-2.2:2.5-3.2. Preferably, the mass ratio of acrylamide to acrylic acid is 1:1-4:1.

[0019] In the above-mentioned method for preparing carbon materials based on ion crosslinking-free radical copolymerization to remove organic sulfur, in step b, the mass percentage concentration of CaCl2 solution is 5% to 8%, the temperature is raised to 60 to 80°C to trigger free radical copolymerization, and the copolymerization reaction time is 3 to 6 hours.

[0020] In the above-mentioned method for preparing carbon materials based on ion crosslinking-free radical copolymerization for removing organic sulfur, in step c, the metal salt solution is a Cu(NO3)2 solution with a concentration of 0.1-0.4 mol / L, the reaction temperature is 25-50℃, the pH is 5-7, and the impregnation time is 6-12 hours.

[0021] In the above-mentioned method for preparing carbon materials based on ion crosslinking-free radical copolymerization for removing organic sulfur, in step d, the carbonization temperature is 550-950℃, the carbonization time is 2-4 hours, the NH3 flow rate is 50mL / min, and the doping time is 0.5-2 hours.

[0022] Another objective of this invention is to provide a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization, which is prepared by the above-mentioned method for preparing a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization. The carbon material has a dual-grid structure, wherein the nitrogen doping includes pyridine N and graphite N, and the metal active site is a Cu-N coordination center.

[0023] Compared with the prior art, the present invention brings the following beneficial technical effects:

[0024] (1) Dual-network collaborative enhancement of structural performance, through Ca2+ The ionic crosslinking of sodium alginate triggers the self-assembly of polymer chains to form a hydrogel with an alternating hydrophobic and hydrophilic double-network interpenetrating structure. Simultaneously, it triggers a free radical copolymerization reaction to construct an alternating hydrophobic and hydrophilic polymer network. The high-molecular-weight double-network interpenetrating structure formed by ionic crosslinking and free radical copolymerization significantly enhances the material's mechanical stability and pore structure controllability, providing high specific surface area and active sites for subsequent metal loading and sulfur adsorption.

[0025] (2) A hierarchical nitrogen-doped optimized structure was achieved by using acrylamide and acrylic acid copolymers as the built-in nitrogen source and introducing NH3 as an exogenous nitrogen dopant during the carbonization process, thus realizing the synergistic distribution of pyridine N and graphitic N. This hierarchical doping structure effectively modulates the electron transfer performance of the carbon matrix and enhances the adsorption and catalytic activity of sulfides.

[0026] (3) Highly efficient anchoring and dispersion of metal ions; the carboxylic acid groups (-COOH) of sodium alginate and acrylic acid are Cu. 2+ It provides uniform anchoring points, avoids agglomeration during high-temperature carbonization, forms highly dispersed metal active centers, and enhances the catalytic oxidation ability of organic sulfur.

[0027] (4) Green process and cost advantages: Using natural high molecular weight sodium alginate as carbon source and combining water and ethanol mixed solvent system, the use of toxic reagents is avoided. Freeze-drying technology retains the porous structure and reduces the pore collapse caused by traditional high temperature drying. The process is more environmentally friendly and has lower energy consumption. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings:

[0029] Figure 1 This is a SEM image of the carbon material prepared in Example 1 of the present invention. Detailed Implementation

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0031] All the raw materials required for this invention can be purchased through commercial channels.

[0032] The evaluation method for the removal of organic sulfur by carbon materials of the present invention is as follows:

[0033] Detection method: A fixed-bed reactor was used, and the concentration of organic sulfur at the outlet was detected by gas chromatography (GC-9720P1us).

[0034] Experimental conditions: air velocity 30,000 h⁻¹ -1The temperature was 25℃. The simulated gas composition was: 25% CO, 400ppm COS, 200ppm CH3SH, 10% CO2, and balanced nitrogen. A saturator system was used to supply water, and the water content was expressed as relative humidity (RH). A mass flow controller was used to control the total flow rate at 50 mL / min.

[0035] The main technical concept of this invention is to prepare highly efficient desulfurization carbon materials with multi-level channels and active sites by synergistic construction strategy of high molecular weight dual network formed by ionic crosslinking and free radical copolymerization, combined with hierarchical nitrogen doping design. Its core technology lies in utilizing Ca... 2+ While inducing sodium alginate to form an ionic cross-linked network, free radical copolymerization of vinyl monomers and block copolymers is initiated by hydrogen peroxide and ferrous ions to form a high molecular weight double-network interpenetrating structure, achieving hydrophobic-hydrophilic micro-region regulation. Acrylamide and acrylic acid copolymers are innovatively used as built-in nitrogen sources, and NH3 is introduced as an exogenous dopant in the synergistic carbonization stage to construct gradient nitrogen active sites mainly composed of pyridine N and graphitic N. Through the integration of in-situ anchoring of metal salts and carbonization process, metal-nitrogen coordination active centers are formed, and carbon materials with high specific surface area, rich surface functional groups and many catalytic active sites are finally obtained.

[0036] The present invention will be further described below with reference to specific embodiments.

[0037] Example 1:

[0038] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0039] Step 1: Disperse 2.8g of sodium alginate in a mixture of 45ml deionized water and 25ml ethanol, stir at 60℃ for 2h until completely dissolved, add 1g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 2.2g of vinyl monomer acrylamide, acrylic copolymer (mass ratio 1:1), 0.2g of initiator hydrogen peroxide, and 0.1g of ferrous ions in sequence, stir at room temperature for 1h to form a homogeneous solution;

[0040] Step 2: Add 10 mL of 6% CaCl2 solution and react for 30 min. Simultaneously, raise the temperature to 70 °C to trigger the decomposition of the initiator, which promotes the free radical copolymerization of vinyl monomers and block copolymers for 6 h to form a hydrophobic and hydrophilic alternating polymer network. Allow to stand for 24 h to ensure that the two networks fully interpenetrate, thus obtaining a high molecular weight hydrogel precursor with a double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization.

[0041] Step 3: Add the precursor to a 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30℃, pH = 6.5, and reaction time at 6h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0042] Step 4: Vacuum freeze drying at -50℃ for 30h; carbonization treatment at 950℃ for 2h, during which NH3 is introduced for 2h at a flow rate of 50mL / min to obtain carbon material.

[0043] Experiments were conducted on the carbon material prepared in this embodiment at a space velocity of 30,000 h⁻¹. -1 The temperature was 25℃. The simulated gas composition was: 25% CO, 400ppm COS, 200ppm CH3SH, 10% CO2, and balanced nitrogen. A saturator system was used to supply water, and the water content was expressed as relative humidity (RH). A mass flow controller was used to control the total flow rate at 50mL / min. The results showed that 100% COS removal rate could be maintained for 12.5h, and 100% CH3SH removal rate could be maintained for 10.5h, indicating that the carbon material has a significant effect on the removal of COS and CH3SH.

[0044] Example 2:

[0045] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0046] Step 1: Disperse 2.5g of sodium alginate in a mixture of 40ml deionized water and 30ml ethanol, stir at 60℃ for 2h until completely dissolved, add 0.8g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 1.5g of vinyl monomer acrylamide, acrylic copolymer (mass ratio 2:1), 0.15g of initiator hydrogen peroxide, and 0.08g of ferrous ions in sequence, stir at room temperature for 1h to form a homogeneous solution;

[0047] Step 2: Add 10 mL of 7% CaCl2 solution and react for 50 min. Simultaneously, raise the temperature to 70 °C to trigger the decomposition of the initiator, which promotes the free radical copolymerization of vinyl monomers and block copolymers for 5 h to form a hydrophobic and hydrophilic alternating polymer network. Allow it to stand for aging for 16 h to ensure that the two networks fully interpenetrate, thus obtaining a high molecular weight hydrogel precursor with a double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization.

[0048] Step 3: Add the precursor to a 0.3 mol / L Cu(NO3)2 solution, control the reaction temperature at 50℃, pH = 5.5, and reaction time at 10 h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0049] Step 4: Vacuum freeze drying at -50℃ for 28 hours; carbonization treatment at 850℃ for 2.5 hours, during which NH3 is introduced for 1.5 hours at a flow rate of 50 mL / min to obtain carbon material.

[0050] The carbon material prepared in this embodiment was tested at room temperature using the same method as in Example 1. The results showed that a 100% COS removal rate could be maintained for 11 hours, and a 100% CH3SH removal rate could be maintained for 9.5 hours, indicating that the carbon material has a significant effect on the removal of COS and CH3SH.

[0051] Example 3:

[0052] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0053] Step 1: Disperse 3g of sodium alginate in a mixture of 50ml deionized water and 20ml ethanol, stir at 60℃ for 2h until completely dissolved, add 0.5g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 2g of vinyl monomer acrylamide, acrylic copolymer (mass ratio 3:1), 0.1g of initiator hydrogen peroxide, and 0.05g of ferrous ions in sequence, stir at room temperature for 1h to form a homogeneous solution;

[0054] Step 2: Add 10 mL of 5% CaCl2 solution and react for 40 min. Simultaneously, raise the temperature to 70 °C to trigger the decomposition of the initiator, which promotes the free radical copolymerization of vinyl monomers and block copolymers for 4 h to form a hydrophobic and hydrophilic alternating polymer network. Allow to stand for 12 h to ensure that the two networks fully interpenetrate, thus obtaining a high molecular weight hydrogel precursor with a double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization.

[0055] Step 3: Add the precursor to a 0.2 mol / L Cu(NO3)2 solution, control the reaction temperature at 40℃, pH=6, and reaction time at 7h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0056] Step 4: Vacuum freeze drying at -50℃ for 24 hours; carbonization treatment at 750℃ for 3 hours, during which NH3 is introduced for 1 hour at a flow rate of 50 mL / min to obtain carbon material.

[0057] The carbon material prepared in this embodiment was tested at room temperature using the same method as in Example 1. The results showed that a 100% COS removal rate could be maintained for 9.5 hours, and a 100% CH3SH removal rate could be maintained for 8 hours, indicating that the carbon material has a significant effect on the removal of COS and CH3SH.

[0058] Example 4:

[0059] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0060] Step 1: Disperse 3.2g of sodium alginate in a mixture of 60ml deionized water and 10ml ethanol, stir at 60℃ for 2h until completely dissolved, add 0.3g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 1.8g of vinyl monomer acrylamide, acrylic copolymer (mass ratio 4:1), 0.12g of initiator hydrogen peroxide, and 0.06g of ferrous ions in sequence, stir at room temperature for 1h to form a homogeneous solution;

[0061] Step 2: Add 10 mL of 8% CaCl2 solution and react for 60 min. Simultaneously, raise the temperature to 70 °C to trigger the decomposition of the initiator, which promotes the free radical copolymerization of vinyl monomers and block copolymers for 3 h to form a hydrophobic and hydrophilic alternating polymer network. Allow it to stand for 10 h to ensure that the two networks fully interpenetrate, thus obtaining a high molecular weight hydrogel precursor with a double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization.

[0062] Step 3: Add the precursor to a 0.1 mol / L Cu(NO3)2 solution, control the reaction temperature at 25℃, pH=7, and reaction time at 12h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0063] Step 4: Vacuum freeze drying at -50℃ for 20h; carbonization treatment at 550℃ for 4h, during which NH3 is introduced for 0.5h at a flow rate of 50mL / min to obtain carbon material.

[0064] The carbon material prepared in this embodiment was tested at room temperature using the same method as in Example 1. The results showed that a 100% COS removal rate could be maintained for 9 hours, and a 100% CH3SH removal rate could be maintained for 6 hours, indicating that the carbon material has a significant effect on the removal of COS and CH3SH.

[0065] Following the guidance of Examples 1 to 4 above, those skilled in the art can also replace the amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate with polystyrene-polyethylene glycol or polystyrene-polyethylene oxide.

[0066] Comparative Example 1:

[0067] The difference from Example 1 is that no amphiphilic block copolymer is added.

[0068] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0069] Step 1: Disperse 2.8g of sodium alginate in a mixture of 45ml of deionized water and 25ml of ethanol, and stir at 60℃ for 2h until completely dissolved. Then, add 2.2g of vinyl monomer acrylamide, acrylic acid copolymer (mass ratio 1:1), 0.2g of initiator hydrogen peroxide, and 0.1g of ferrous ions in sequence, and stir at room temperature for 1h to form a homogeneous solution.

[0070] Step 2: Add 10 mL of 6% CaCl2 solution and react for 30 min. At the same time, raise the temperature to 70 °C to trigger the decomposition of the initiator and promote the copolymerization of vinyl monomers.

[0071] Step 3: Add the sample prepared above to a 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30℃, pH = 6.5, and reaction time at 6h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0072] Step 4: Vacuum freeze drying at -50℃ for 30h; carbonization treatment at 950℃ for 2h, during which NH3 is introduced for 2h at a flow rate of 50mL / min to obtain carbon material.

[0073] The results showed that the 100% COS removal rate could be maintained for 4.5 hours and the 100% CH3SH removal rate could be maintained for 4 hours, indicating that the carbon material has a significant effect on reducing the removal of COS and CH3SH.

[0074] Comparative Example 2:

[0075] The difference from Example 1 is that no initiator was used.

[0076] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0077] Step 1: Disperse 2.8g of sodium alginate in a mixture of 45ml deionized water and 25ml ethanol, stir at 60℃ for 2h until completely dissolved, add 1g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 2.2g of vinyl monomer acrylamide and acrylic acid copolymer (mass ratio 1:1), stir at room temperature for 1h to form a homogeneous solution;

[0078] Step 2: Add 10 mL of 6% CaCl2 solution, react for 30 min, and let stand for 24 h to age.

[0079] Step 3: Add the sample prepared above to a 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30℃, pH = 6.5, and reaction time at 6h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0080] Step 4: Vacuum freeze drying at -50℃ for 30h; carbonization treatment at 950℃ for 2h, during which NH3 is introduced for 2h at a flow rate of 50mL / min to obtain carbon material.

[0081] The results showed that the 100% COS removal rate could be maintained for 4 hours and the 100% CH3SH removal rate could be maintained for 3.5 hours, indicating that the carbon material has a significant effect on reducing the removal of COS and CH3SH.

[0082] Comparative Example 3:

[0083] The difference from Example 1 is that a vinyl monomer without a built-in nitrogen source was used.

[0084] Step 1: Disperse 2.8g of sodium alginate in a mixture of 45ml deionized water and 25ml ethanol, stir at 60℃ for 2h until completely dissolved, add 1g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 2.2g of vinyl monomer styrene, methacrylic acid copolymer (mass ratio 1:1), 0.2g of initiator hydrogen peroxide, and 0.1g of ferrous ions in sequence, stir at room temperature for 1h to form a homogeneous solution;

[0085] Step 2: Add 10 mL of 6% CaCl2 solution and react for 30 min. Simultaneously, raise the temperature to 70 °C to trigger the decomposition of the initiator, which promotes the free radical copolymerization of vinyl monomers and block copolymers for 6 h to form a hydrophobic and hydrophilic alternating polymer network. Allow to stand for 24 h to ensure that the two networks fully interpenetrate, thus obtaining a high molecular weight hydrogel precursor with a double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization.

[0086] Step 3: Add the precursor to a 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30℃, pH = 6.5, and reaction time at 6h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0087] Step 4: Vacuum freeze drying at -50℃ for 30h; carbonization treatment at 950℃ for 2h, during which NH3 is introduced for 2h at a flow rate of 50mL / min to obtain carbon material.

[0088] The results showed that a 100% COS removal rate could be maintained for 5.5 hours and a 100% CH3SH removal rate could be maintained for 4 hours, indicating that the carbon material had a significant effect on reducing the removal of COS and CH3SH.

[0089] Comparative Example 4:

[0090] The difference from Example 1 is that the metal salt is replaced with Fe(NO3)3.

[0091] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0092] Step 1: Disperse 2.8g of sodium alginate in a mixture of 45ml deionized water and 25ml ethanol, stir at 60℃ for 2h until completely dissolved, add 1g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 2.2g of vinyl monomer acrylamide, acrylic copolymer (mass ratio 1:1), 0.2g of initiator hydrogen peroxide, and 0.1g of ferrous ions in sequence, stir at room temperature for 1h to form a homogeneous solution;

[0093] Step 2: Add 10 mL of 6% CaCl2 solution and react for 30 min. Simultaneously, raise the temperature to 70 °C to trigger the decomposition of the initiator, which promotes the free radical copolymerization of vinyl monomers and block copolymers for 6 h to form a hydrophobic and hydrophilic alternating polymer network. Allow to stand for 24 h to ensure that the two networks fully interpenetrate, thus obtaining a high molecular weight hydrogel precursor with a double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization.

[0094] Step 3: Add the precursor to a 0.4 mol / L Fe(NO3)3 solution, control the reaction temperature at 30℃, pH = 6.5, and reaction time at 6h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0095] Step 4: Vacuum freeze drying at -50℃ for 30h; carbonization treatment at 950℃ for 2h, during which NH3 is introduced for 2h at a flow rate of 50mL / min to obtain carbon material.

[0096] The results showed that the 100% COS removal rate could be maintained for 5 hours and the 100% CH3SH removal rate could be maintained for 4.5 hours, indicating that the carbon material has a significant effect on reducing the removal of COS and CH3SH.

[0097] Comparative Example 5:

[0098] The difference from Example 1 is that no NH3 is introduced during the carbonization process.

[0099] A method for preparing carbon materials based on ion crosslinking-free radical copolymerization for the removal of organic sulfur includes the following steps:

[0100] Step 1: Disperse 2.8g of sodium alginate in a mixture of 45ml deionized water and 25ml ethanol, stir at 60℃ for 2h until completely dissolved, add 1g of amphiphilic block copolymer polystyrene-b-polyoxyethylene glycidyl acrylate, sonicate for 30min to eliminate aggregation, then add 2.2g of vinyl monomer acrylamide, acrylic copolymer (mass ratio 1:1), 0.2g of initiator hydrogen peroxide, and 0.1g of ferrous ions in sequence, stir at room temperature for 1h to form a homogeneous solution;

[0101] Step 2: Add 10 mL of 6% CaCl2 solution and react for 30 min. Simultaneously, raise the temperature to 70 °C to trigger the decomposition of the initiator, which promotes the free radical copolymerization of vinyl monomers and block copolymers for 6 h to form a hydrophobic and hydrophilic alternating polymer network. Allow to stand for 24 h to ensure that the two networks fully interpenetrate, thus obtaining a high molecular weight hydrogel precursor with a double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization.

[0102] Step 3: Add the precursor to a 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30℃, pH = 6.5, and reaction time at 6h, so that the metal ions are uniformly dispersed and anchored to the sodium alginate network;

[0103] Step 4: Vacuum freeze drying at -50℃ for 30 hours; carbonization treatment at 950℃ for 2 hours to obtain carbon material.

[0104] The results showed that the 100% COS removal rate could be maintained for 4.5 hours and the 100% CH3SH removal rate could be maintained for 3 hours, indicating that the carbon material has a significant effect on reducing the removal of COS and CH3SH.

[0105] Any parts not mentioned in this invention can be achieved by referring to existing technologies.

[0106] Those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any appropriate changes and variations made to the above embodiments within the essential spirit and scope of this application fall within the scope of protection claimed in this application.

Claims

1. A method for producing a carbon material based on ion crosslinking-radical copolymerization removal of organic sulfur, characterized by, Comprise the following steps in sequence: a. Dissolve sodium alginate to obtain a sodium alginate solution, and sequentially add polystyrene-polyether amphiphilic block copolymer, acrylamide-acrylic acid copolymer, initiator and ferrous ion to the sodium alginate solution to form a homogeneous solution; b. Drop CaCl2 solution into the homogeneous solution, and trigger the decomposition of the initiator by increasing the temperature to make the polystyrene-polyether amphiphilic block copolymer and the acrylamide-acrylic acid copolymer undergo radical copolymerization to form a hydrogel precursor, wherein the hydrogel precursor has a hydrophobic-hydrophilic alternating double-network interpenetrating structure; c. Immerse the hydrogel precursor in a metal salt solution to make metal ions uniformly disperse and anchor in the double-network interpenetrating structure of the hydrogel precursor; d. Perform vacuum freeze-drying treatment on the sample obtained in step c, and then introduce NH3 for high-temperature carbonization, wherein NH3 provides exogenous nitrogen doping and combines with the acrylamide-acrylic acid copolymer in the hydrogel precursor as an internal nitrogen source to obtain a carbon material with a hierarchical nitrogen-doped structure.

2. The method according to claim 1, wherein the method is characterized by: In step a, the sodium alginate is dispersed in a deionized water-ethanol mixed solution, and the temperature is controlled at 50-70℃ for stirring for 1-3h for dissolution.

3. The method according to claim 1, wherein the method is characterized by: In step a, the polystyrene-polyether amphiphilic block copolymer is polystyrene-polyethylene glycol, polystyrene-polyethylene oxide or polystyrene-b-polyoxyethylene glycidyl acrylate; and the initiator is a peroxide initiator.

4. The method according to claim 3, wherein the method is characterized by: The polystyrene-polyether amphiphilic block copolymer is polystyrene-b-polyoxyethylene glycidyl acrylate; and the initiator is hydrogen peroxide.

5. The method according to claim 1, wherein the method is characterized by: In step a, the mass ratio of the polystyrene-polyether amphiphilic block copolymer to the sodium alginate is 0.3-1:2.5-3.2; and the mass ratio of the acrylamide-acrylic acid copolymer to the sodium alginate is 1.5-2.2:2.5-3.

2.

6. The method according to claim 1, wherein the method is characterized by: In step b, the mass percentage concentration of the CaCl2 solution is 5%-8%, the temperature is increased to 60-80℃ to trigger the radical copolymerization, and the copolymerization reaction time is 3-6 hours.

7. The method according to claim 1, wherein the method is characterized by: In step c, the metal salt solution is a Cu(NO3)2 solution, the concentration of which is 0.1-0.4 mol / L, the reaction temperature is 25-50℃, the pH is 5-7, and the immersion time is 6-12 hours.

8. The method according to claim 1, wherein the method is characterized by: In step d, the carbonization temperature is 550-950℃, the carbonization time is 2-4 hours, the flow rate of NH3 introduction is 50 mL / min, and the doping time is 0.5-2 hours.

9. A carbon material based on ion crosslinking-radical copolymerization for removing organic sulfur, characterized by, The carbon material is prepared by the method of any one of claims 1-8, and has a double-network structure, wherein the nitrogen doping includes pyridine N and graphite N, and the metal active site is a Cu-N coordination center.

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