Carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization and preparation method

Abstract

The invention discloses a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization and a preparation method, and relates to the technical field of preparation of carbon materials. Ca < 2 + > and sodium alginate synchronously react with a vinyl monomer and a polystyrene-polyether amphiphilic block copolymer, so that a high-molecular-weight double-network interpenetrating structure formed by ionic crosslinking and free radical copolymerization is constructed. Acrylamide and an acrylic copolymer are adopted as a built-in nitrogen source, NH3 is introduced in the carbonization process to serve as exogenous nitrogen doping, and a graded nitrogen doping structure rich in pyridine N and graphite N is achieved. By optimizing raw material selection and improving a preparation process and a surface modification technology, the carbon material with efficient desulfurization performance is produced, and the method disclosed by the invention has the advantages of lower production cost and excellent desulfurization effect, and can realize efficient and economical removal of organic sulfur in a natural gas purification process.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon material preparation, and particularly relates to a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization and a preparation method thereof. Background Art

[0002] With the continuous growth of global energy demand, natural gas, as a clean energy source, has become one of the important energy sources. However, natural gas usually contains a certain amount of organic sulfides (such as carbonyl sulfide, methanethiol, etc.). These organic sulfides not only affect the quality of natural gas, but also generate sulfur dioxide during the combustion process, 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, the methods for removing organic sulfur mainly include physical adsorption, chemical adsorption, and catalytic methods, etc. Among them, the adsorption method has received extensive attention due to its simple operation and low cost. Adsorption materials usually include metal oxides, molecular sieves, activated carbon, and some modified carbon materials, etc. However, conventional adsorption materials have some limitations in the process of treating organic sulfur in natural gas, such as low adsorption capacity, difficult regeneration, and short service life, etc.

[0004] To overcome these drawbacks, carbon materials, as an adsorption medium with a high specific surface area, adjustable pore structure, and excellent chemical stability, have become an important research direction in desulfurization technologies. In recent years, researchers have aimed to improve the adsorption capacity and catalytic performance of carbon materials by adjusting the preparation process and modification methods of carbon materials. Carbon materials such as activated carbon, graphene, and carbon nanotubes have shown good application potential in removing organic sulfur, but there are still some problems in the existing carbon material preparation methods, such as high preparation cost and complex production process, etc.

[0005] It can be seen that the existing technology needs to be further improved. Summary of the Invention

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

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A preparation method of a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization successively includes the following steps:

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

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

[0011] c. Immerse the hydrogel precursor in a metal salt solution so that metal ions are uniformly dispersed and anchored in the double network interpenetrating structure of the hydrogel precursor;

[0012] d. Perform vacuum freeze-drying treatment on the sample obtained in step c; then introduce NH3 for high-temperature carbonization. NH3 provides external nitrogen doping and combines with the copolymer of acrylamide and acrylic acid as the internal nitrogen source in the hydrogel precursor to obtain a carbon material with a hierarchical nitrogen-doped structure.

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

[0014] This technical solution reacts Ca 2+ , sodium alginate, vinyl monomers, and polystyrene-polyether amphiphilic block copolymers synchronously to construct a high molecular weight double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization. And use the copolymer of acrylamide and acrylic acid as the internal nitrogen source, and introduce NH3 as external nitrogen doping during the carbonization process to realize a hierarchical nitrogen-doped structure rich in pyridine N and graphite N. The epoxy groups in the amphiphilic block copolymer react with the amino groups in the vinyl monomers acrylamide and acrylic acid copolymer and the carboxyl groups in sodium alginate to generate hydroxyl groups, providing a strong alkaline environment for the removal of organic sulfur. This material has the characteristics of high specific surface area, hierarchical pores, and uniform distribution of Cu-N active sites, and shows excellent adsorption and catalytic synergistic efficiency in the removal of organic sulfur. Its preparation process innovatively combines biomass templates, controlled polymerization, and hierarchical nitrogen doping technologies to realize the development of carbon-based functional materials with low cost, environmental friendliness, and scalable production, providing a new solution for the efficient removal of organic sulfur.

[0015] In the above preparation method of a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization, in step a, sodium alginate is dispersed in a mixed solution of deionized water and ethanol, and the temperature is controlled at 50-70 °C and stirred for 1-3 h for dissolution.

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

[0017] In the above preparation method of a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization, the polystyrene-polyether amphiphilic block copolymer is polystyrene-b-polyoxyethylene glycidyl acrylate; the initiator is hydrogen peroxide.

[0018] In the above preparation method of a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization, in step a, the mass ratio of the polystyrene-polyether amphiphilic block copolymer to sodium alginate is 0.3-1:2.5-3.2; the mass ratio of the copolymer of acrylamide and acrylic acid 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 preparation method of a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization, in step b, the mass percentage concentration of the CaCl2 solution is 5%-8%, and the temperature is raised to 60-80°C to trigger free radical copolymerization, and the copolymerization reaction time is 3-6 hours.

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

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

[0022] Another object of the present invention is to provide a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization, which is prepared by using the above preparation method of a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization. The carbon material has a double-grid structure, the nitrogen doping therein 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) The double-network synergistic enhancement structure performance, through Ca2+ Trigger the ionic crosslinking of sodium alginate to promote the self-assembly of polymer chains to form a hydrogel with a hydrophobic-hydrophilic alternating double-network interpenetrating structure. Meanwhile, trigger the free radical copolymerization reaction to construct a hydrophobic-hydrophilic alternating polymer network. The high molecular weight double-network interpenetrating structure formed by ionic crosslinking and free radical copolymerization significantly improves the mechanical stability of the material and the ability to regulate the pore structure, providing a high specific surface area and active sites for subsequent metal loading and sulfur adsorption.

[0025] (2) Hierarchical nitrogen doping to optimize the structure. Using acrylamide and acrylic acid copolymer as an internal nitrogen source, combined with the introduction of NH3 during the carbonization process as an external nitrogen doping, realizing the synergistic distribution of pyridine N and graphite N. This hierarchical doping structure effectively regulates the electron transfer performance of the carbon matrix and improves the sulfide adsorption and catalytic activity.

[0026] (3) Efficient anchoring and dispersion of metal ions. The carboxyl groups (-COOH) of sodium alginate and acrylic acid provide uniform anchoring sites for Cu 2+ to avoid agglomeration during the high-temperature carbonization process, forming highly dispersed metal active centers and enhancing the catalytic oxidation ability of organic sulfur.

[0027] (4) Green process and cost advantages. Using natural polymer sodium alginate as a carbon source, combined with a water-ethanol mixed solvent system, avoiding the use of toxic reagents. The 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. Brief Description of the Drawings

[0028] The present invention will be further described below in conjunction with the drawings:

[0029] Figure 1 SEM image of the carbon material prepared in Example 1 of the present invention. Detailed Embodiments

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

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

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

[0033] Detection method: Use a fixed-bed reactor and a gas chromatograph (GC-9720P1us) to detect the concentration of organic sulfur at the outlet.

[0034] Experimental conditions: Space velocity 30000h -1, The temperature is 25 °C. The simulated gas composition is: 25% CO, 400 ppm COS, 200 ppm CH3SH, 10% CO2, and balanced nitrogen. A saturator system is used to supply water, and the water content is expressed as relative humidity (RH). A mass flow controller is used to control the total flow rate at 50 mL / min.

[0035] The main technical concept of the present invention is: through a high-molecular-weight double-network synergistic construction strategy formed by ionic crosslinking and free radical copolymerization, combined with a hierarchical nitrogen doping design, to prepare an efficient desulfurization carbon material with hierarchical pores and active sites. The core technology lies in using Ca 2+ While inducing sodium alginate to form an ionic crosslinked network, through hydrogen peroxide and ferrous ions to initiate the free radical copolymerization of vinyl monomers and block copolymers, a high-molecular-weight double-network interpenetrating structure is formed to achieve the regulation of hydrophobic-hydrophilic microdomains; innovatively using acrylamide and acrylic acid copolymer as an internal nitrogen source, and synergistically introducing NH3 as an external doping during the carbonization stage to construct gradient nitrogen active sites mainly composed of pyridine N and graphite N; through the in-situ anchoring of metal salts and the integration of the carbonization process, a metal-nitrogen coordination active center is formed, and finally a carbon material with a high specific surface area, rich surface functional groups, and many catalytic active sites is obtained.

[0036] The following further illustrates the present invention with specific examples.

[0037] Example 1:

[0038] A preparation method of a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization, comprising the following steps:

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

[0040] Step 2: Dropwise add 10 mL of 6% CaCl2 solution, react for 30 min, and at the same time raise the temperature to 70 °C to trigger the decomposition of the initiator, promote the free radical copolymerization of vinyl monomers and block copolymers for 6 h, form a hydrophobic-hydrophilic alternating polymer network, and stand for aging for 24 h to ensure full interpenetration of the double network, that is, obtain a hydrogel precursor with a high-molecular-weight double-network interpenetrating structure formed by ionic crosslinking and free radical copolymerization;

[0041] Step 3: Add the precursor into 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30 °C, pH = 6.5, and reaction time at 6 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0042] Step 4: Conduct vacuum freeze-drying at -50 °C for 30 h; perform carbonization treatment at 950 °C for 2 h. Introduce NH3 during the high-temperature carbonization process for 2 h with a flow rate of 50 mL / min to obtain the carbon material.

[0043] Experiment was conducted on the carbon material prepared in this example with an airspeed of 30000 h -1 , and the temperature was 25 °C. The simulated gas composition was: 25% CO, 400 ppm COS, 200 ppm CH3SH, 10% CO2, and balance nitrogen. A saturator system was used to supply water and the water content was expressed by relative humidity (RH). A mass flow controller was used to control the total flow rate at 50 mL / min. The results showed that the 100% COS removal rate could be maintained for 12.5 h and the 100% CH3SH removal rate could be maintained for 10.5 h, indicating that the carbon material had obvious effects on the removal of COS and CH3SH.

[0044] Example 2:

[0045] A preparation method of a carbon material for removing organic sulfur based on ion cross-linking - free radical copolymerization, comprising the following steps:

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

[0047] Step 2: Dropwise add 10 mL of 7% CaCl2 solution, react for 50 min, and simultaneously raise the temperature to 70 °C to trigger the decomposition of the initiator, promote the free radical copolymerization of vinyl monomers and block copolymer for 5 h to form a hydrophobic-hydrophilic alternating polymer network, and let it stand and age for 16 h to ensure that the double networks fully interpenetrate, thus obtaining a hydrogel precursor with a high molecular weight double network interpenetrating structure formed by ion cross-linking and free radical copolymerization;

[0048] Step 3: Add the precursor into 0.3 mol / L Cu(NO3)2 solution, control the reaction temperature at 50 °C, pH = 5.5, and reaction time at 10 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0049] Step 4: Vacuum freeze-dry at -50°C for 28 h; carbonize at 850°C for 2.5 h, introduce NH3 during the high-temperature carbonization process for 1.5 h with a flow rate of 50 mL / min to obtain the carbon material.

[0050] The carbon material prepared in this example was tested at room temperature, and the specific method was the same as that in Example 1. The results showed that the 100% COS removal rate could be maintained for 11 h, and the 100% CH3SH removal rate could be maintained for 9.5 h, indicating that the carbon material has obvious effects on the removal of COS and CH3SH.

[0051] Example 3:

[0052] A preparation method of a carbon material for removing organic sulfur based on ion cross-linking-free radical copolymerization, comprising the following steps:

[0053] Step 1: Disperse 3 g of sodium alginate in a mixed solution of 50 ml of deionized water and 20 ml of ethanol, stir at 60°C for 2 h until completely dissolved, add 0.5 g of amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) glycidyl acrylate, ultrasonically treat for 30 min to eliminate aggregation, and sequentially add 2 g of vinyl monomers acrylamide and acrylic acid copolymer (mass ratio 3:1) and 0.1 g of initiator hydrogen peroxide and 0.05 g of ferrous ions, and stir at room temperature for 1 h to form a homogeneous solution;

[0054] Step 2: Dropwise add 10 mL of 5% CaCl2 solution, react for 40 min, and simultaneously raise the temperature to 70°C to trigger the decomposition of the initiator, promote the free radical copolymerization of vinyl monomers and block copolymer for 4 h to form a hydrophobic-hydrophilic alternating polymer network, and let it stand and age for 12 h to ensure that the double network fully interpenetrates, that is, obtain a hydrogel precursor with a high molecular weight double network interpenetrating structure formed by ion cross-linking and free radical copolymerization;

[0055] Step 3: Add the precursor to 0.2 mol / L Cu(NO3)2 solution, control the reaction temperature at 40°C, pH = 6, and reaction time at 7 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0056] Step 4: Vacuum freeze-dry at -50°C for 24 h; carbonize at 750°C for 3 h, introduce NH3 during the high-temperature carbonization process for 1 h with a flow rate of 50 mL / min to obtain the carbon material.

[0057] The carbon material prepared in this example was tested at room temperature, and the specific method was the same as that in Example 1. The results showed that the 100% COS removal rate could be maintained for 9.5 h, and the 100% CH3SH removal rate could be maintained for 8 h, indicating that the carbon material has obvious effects on the removal of COS and CH3SH.

[0058] Example 4:

[0059] A preparation method of a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization, comprising the following steps:

[0060] Step 1: Disperse 3.2 g of sodium alginate in a mixed solution of 60 ml of deionized water and 10 ml of ethanol, stir at 60 °C for 2 h until completely dissolved, add 0.3 g of amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) glycidyl acrylate, and perform ultrasonic treatment for 30 min to eliminate aggregation. Then, successively add 1.8 g of vinyl monomers acrylamide and acrylic acid copolymer (mass ratio 4:1) and 0.12 g of initiator hydrogen peroxide and 0.06 g of ferrous ions, and stir at room temperature for 1 h to form a homogeneous solution;

[0061] Step 2: Dropwise add 10 mL of 8% CaCl2 solution, react for 60 min, and simultaneously raise the temperature to 70 °C to trigger the decomposition of the initiator, promote the free radical copolymerization of vinyl monomers and block copolymer for 3 h to form a hydrophobic-hydrophilic alternating polymer network, and let it stand and age for 10 h to ensure that the double network fully interpenetrates, thus obtaining a hydrogel precursor with a high molecular weight double network interpenetrating structure formed by ion crosslinking and free radical copolymerization;

[0062] Step 3: Add the precursor to 0.1 mol / L Cu(NO3)2 solution, control the reaction temperature at 25 °C, pH = 7, and reaction time at 12 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0063] Step 4: Vacuum freeze-dry at -50 °C for 20 h; carbonize at 550 °C for 4 h, introduce NH3 during the high-temperature carbonization process for 0.5 h, and the flow rate is 50 mL / min to obtain the carbon material.

[0064] The carbon material prepared in this example was tested at room temperature, and the specific method was the same as that in Example 1. The results showed that the 100% COS removal rate could be maintained for 9 h, and the 100% CH3SH removal rate could be maintained for 6 h, indicating that the carbon material had obvious effects on the removal of COS and CH3SH.

[0065] Under the guidance of the above Examples 1 to 4, those skilled in the art can also replace the amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) glycidyl acrylate with polystyrene-polyethylene glycol and polystyrene-polyethylene oxide.

[0066] Comparative Example 1:

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

[0068] A preparation method of a carbon material for removing organic sulfur based on ion crosslinking-free radical copolymerization, comprising the following steps:

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

[0070] Step 2: Dropwise add 10 mL of 6% CaCl2 solution, react for 30 min, and simultaneously 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 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30 °C, pH = 6.5, and reaction time at 6 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0072] Step 4: Vacuum freeze-dry at -50 °C for 30 h; carbonize at 950 °C for 2 h, introduce NH3 during the high-temperature carbonization process for 2 h at a flow rate of 50 mL / min to obtain a carbon material.

[0073] The results show that a 100% COS removal rate can be maintained for 4.5 h, and a 100% CH3SH removal rate can be maintained for 4 h, indicating that the carbon material has an obvious effect on reducing the removal of COS and CH3SH.

[0074] Comparative Example 2:

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

[0076] A preparation method of a carbon material for removing organic sulfur based on ion cross-linking-free radical copolymerization, comprising the following steps:

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

[0078] Step 2: Dropwise add 10 mL of 6% CaCl2 solution, react for 30 min, and stand for aging for 24 h;

[0079] Step 3: Add the sample prepared above to 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30 °C, pH = 6.5, and reaction time at 6 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0080] Step 4: Vacuum freeze-dry at -50°C for 30 h; carbonize at 950°C for 2 h, introducing NH3 during the high-temperature carbonization process for 2 h with a flow rate of 50 mL / min to obtain a carbon material.

[0081] The results show that a 100% COS removal rate can be maintained for 4 h and a 100% CH3SH removal rate can be maintained for 3.5 h, indicating that the carbon material has an obvious 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 an internal nitrogen source was used.

[0084] Step 1: Disperse 2.8 g of sodium alginate in a mixed solution of 45 ml of deionized water and 25 ml of ethanol, stir at 60°C for 2 h until completely dissolved, add 1 g of amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) glycidyl methacrylate, perform ultrasonic treatment for 30 min to eliminate aggregation, and sequentially add 2.2 g of vinyl monomers styrene and methacrylic acid copolymer (mass ratio 1:1) and 0.2 g of initiator hydrogen peroxide and 0.1 g of ferrous ion, and stir at room temperature for 1 h to form a homogeneous solution;

[0085] Step 2: Dropwise add 10 mL of 6% CaCl2 solution, react for 30 min, and simultaneously raise the temperature to 70°C to trigger the decomposition of the initiator, promoting the free radical copolymerization of vinyl monomers and block copolymers for 6 h to form a hydrophobic-hydrophilic alternating polymer network, and let it stand and age for 24 h to ensure that the double network fully interpenetrates, obtaining a hydrogel precursor with a high molecular weight double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization;

[0086] Step 3: Add the precursor to 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30°C, pH = 6.5, and reaction time at 6 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0087] Step 4: Vacuum freeze-dry at -50°C for 30 h; carbonize at 950°C for 2 h, introducing NH3 during the high-temperature carbonization process for 2 h with a flow rate of 50 mL / min to obtain a carbon material.

[0088] The results show that a 100% COS removal rate can be maintained for 5.5 h and a 100% CH3SH removal rate can be maintained for 4 h, indicating that the carbon material has an obvious effect on reducing the removal of COS and CH3SH.

[0089] Comparative Example 4:

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

[0091] A preparation method of a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization, comprising the following steps:

[0092] Step 1: Disperse 2.8 g of sodium alginate in a mixed solution of 45 ml of deionized water and 25 ml of ethanol, stir at 60 °C for 2 h until completely dissolved, add 1 g of amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) glycidyl acrylate, and perform ultrasonic treatment for 30 min to eliminate aggregation. Then, sequentially add 2.2 g of vinyl monomers acrylamide and acrylic acid copolymer (mass ratio 1:1) and 0.2 g of initiator hydrogen peroxide and 0.1 g of ferrous ions, and stir at room temperature for 1 h to form a homogeneous solution;

[0093] Step 2: Dropwise add 10 mL of 6% CaCl2 solution, react for 30 min, and simultaneously raise the temperature to 70 °C to trigger the decomposition of the initiator, and promote the free radical copolymerization of vinyl monomers and block copolymer for 6 h to form a hydrophobic-hydrophilic alternating polymer network. Let it stand and age for 24 h to ensure that the double network fully interpenetrates, and obtain a hydrogel precursor with a high molecular weight double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization;

[0094] Step 3: Add the precursor to 0.4 mol / L Fe(NO3)3 solution, control the reaction temperature at 30 °C, pH = 6.5, and reaction time at 6 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0095] Step 4: Vacuum freeze-dry at -50 °C for 30 h; perform carbonization treatment at 950 °C for 2 h, introduce NH3 during the high-temperature carbonization process for 2 h, and the flow rate is 50 mL / min to obtain the carbon material.

[0096] The results show that: the 100% COS removal rate can be maintained for 5 h, and the 100% CH3SH removal rate can be maintained for 4.5 h, indicating that the carbon material has an obvious effect on reducing the removal of COS and CH3SH.

[0097] Comparative Example 5:

[0098] The difference from Example 1 is that NH3 is not introduced during the carbonization process.

[0099] A preparation method of a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization, comprising the following steps:

[0100] Step 1: Dissolve 2.8 g of sodium alginate in a mixed solution of 45 ml of deionized water and 25 ml of ethanol. Stir at 60 °C for 2 h until completely dissolved. Add 1 g of amphiphilic block copolymer polystyrene-b-poly(ethylene oxide) glycidyl acrylate, and ultrasonically treat for 30 min to eliminate aggregation. Then, sequentially add 2.2 g of vinyl monomers acrylamide and acrylic acid copolymer (mass ratio 1:1) and 0.2 g of initiator hydrogen peroxide and 0.1 g of ferrous ions, and stir at room temperature for 1 h to form a homogeneous solution;

[0101] Step 2: Dropwise add 10 mL of 6% CaCl2 solution, react for 30 min, and simultaneously raise the temperature to 70 °C to trigger the decomposition of the initiator, promoting the free radical copolymerization of vinyl monomers and block copolymer for 6 h to form a hydrophobic-hydrophilic alternating polymer network. Let it stand and age for 24 h to ensure full interpenetration of the double network, thus obtaining a hydrogel precursor with a high molecular weight double network interpenetrating structure formed by ionic crosslinking and free radical copolymerization;

[0102] Step 3: Add the precursor to 0.4 mol / L Cu(NO3)2 solution, control the reaction temperature at 30 °C, pH = 6.5, and reaction time at 6 h to uniformly disperse and anchor metal ions in the sodium alginate network;

[0103] Step 4: Vacuum freeze-dry at -50 °C for 30 h; carbonize at 950 °C for 2 h to obtain a carbon material.

[0104] The results show that the 100% COS removal rate can be maintained for 4.5 h, and the 100% CH3SH removal rate can be maintained for 3 h, indicating that the carbon material has an obvious effect on reducing the removal of COS and CH3SH.

[0105] The parts not described in the present invention can be realized by referring to the prior art.

[0106] Those of ordinary skill in the art of this technology should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. As long as within the scope of the spirit of the present application, appropriate changes and variations made to the above embodiments fall within the scope of protection required by the present application.

Claims

1. A method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization, characterized in that: The following steps are included in sequence: a. dissolving sodium alginate to obtain a sodium alginate solution, and sequentially adding a polystyrene-polyether type amphiphilic block copolymer, a copolymer of acrylamide and acrylic acid, an initiator, and ferrous ions to the sodium alginate solution to form a homogeneous solution; b. Adding a CaCl2 solution dropwise to the homogeneous solution, heating the solution 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 having a hydrophobic-hydrophilic alternating double-network interpenetrating structure; c. Immersing the hydrogel precursor in a metal salt solution so that the metal ions are evenly dispersed and anchored in the double-network interpenetrating structure of the hydrogel precursor; d. The sample obtained in step c is subjected to vacuum freeze-drying treatment; then NH3 is introduced for high-temperature carbonization, wherein NH3 provides exogenous nitrogen doping and combines with the copolymer of acrylamide and acrylic acid as a built-in nitrogen source in the hydrogel precursor to obtain a carbon material with a graded nitrogen-doped structure.

2. The method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization according to claim 1, characterized in that: In step a, sodium alginate is dispersed in a mixed solution of deionized water and ethanol, and the temperature is controlled to be 50-70° C. and stirred for 1-3 hours to dissolve.

3. The method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization according to claim 1, characterized in that: 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.

4. The method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization according to claim 3, characterized in that: The polystyrene-polyether type amphiphilic block copolymer is polystyrene-b-polyoxyethylene glycidyl acrylate; and the initiator is hydrogen peroxide.

5. The method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization according to claim 1, characterized in that: In step a, the mass ratio of the polystyrene-polyether type amphiphilic block copolymer to sodium alginate is 0.3-1:2.5-3.2; the mass ratio of the copolymer of acrylamide and acrylic acid to sodium alginate is 1.5-2.2:2.5-3.

2.

6. The method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization according to claim 1, characterized in that: In step b, the mass percentage concentration of the CaCl2 solution is 5% to 8%, and the temperature is raised to 60 to 80°C to trigger free radical copolymerization, and the copolymerization reaction time is 3 to 6 hours.

7. The method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization according to claim 1, characterized in that: In step c, the metal salt solution is a Cu(NO3)2 solution with a concentration of 0.1-0.4 mol / L, a reaction temperature of 25-50°C, a pH of 5-7, and an immersion time of 6-12 hours.

8. The method for preparing a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization according to claim 1, characterized in that: In step d, the carbonization temperature is 550-950° C., the carbonization time is 2-4 hours, the NH3 introduction rate is 50 mL / min, and the doping time is 0.5-2 hours.

9. A carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization, characterized in that: It is prepared by the preparation method of a carbon material for removing organic sulfur based on ionic crosslinking-free radical copolymerization as described in any one of claims 1 to 8, wherein the carbon material has a double grid 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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