A nitrogen-modified ordered core-shell desulfurizing agent, its preparation method and application

Abstract

This invention relates to the field of air pollution control technology, providing a nitrogen-modified ordered core-shell desulfurizer, its preparation method, and its applications. This invention utilizes a carbon source as the core, forming a metal-modified silicon-based ordered porous shell through a silicon source and a template agent. Nitrogen modification is then achieved through calcination in an ammonia-containing atmosphere, forming an M-N-C structure (M being a metal) and amino functional groups on the surface, ultimately yielding a nitrogen-modified ordered core-shell desulfurizer for the catalytic removal of organic sulfur. The nitrogen-modified ordered core-shell desulfurizer synthesized by this invention possesses a regular surface structure and abundant pore structure, which is beneficial for the adsorption and catalytic removal of organic sulfur. Nitrogen modification can increase the surface alkaline functional groups of the desulfurizer, effectively improving its chemical adsorption capacity and service life, providing more possibilities for the industrial application of desulfurizers. Example results show that the desulfurizer of this invention can achieve a desulfurization rate of 100% under low-temperature conditions (≤100℃).

Description

Technical Field

[0001] This invention relates to the field of air pollution control technology, and in particular to a nitrogen-modified ordered core-shell structured desulfurizer, its preparation method, and its application. Background Technology

[0002] Carbonyl sulfide (COS) and methanethiol (CH3SH) are common organic sulfur pollutants in industrial production, mostly existing as associated gases in energy production. The presence of COS and CH3SH not only significantly impacts the utilization of energy gases but also produces pungent odors. Their release into production and living environments poses serious threats to human health and ecological safety. Therefore, the simultaneous purification of multiple organic sulfur compounds in energy gases is urgently needed.

[0003] Currently, desulfurization processes are broadly classified into wet and dry methods. Compared to wet desulfurization, dry desulfurization offers advantages such as better gas volume adaptability, higher desulfurization efficiency, simpler operation, and no secondary pollution. Among various dry desulfurizing agents, carbon-based materials possess both economic and environmental advantages and are widely used in the purification of organic sulfur. However, traditional activated carbon has low water and sulfur resistance, requiring frequent replacement in practical applications. Therefore, necessary optimization of the surface structure of the desulfurizing agent is required. In summary, current research on organic sulfur purification mainly focuses on disordered supported catalysts, but the desulfurization performance and service life of these catalysts still do not meet requirements.

[0004] Chinese patent CN115739095A discloses "a preparation method and application of Ni-Co@C carbon core-shell hydrophobic nanoparticle catalyst". This method uses Ni-Co bimetallic MOF crystal layers as a precursor and phenyl dicarboxylic acid or polycarboxylic acid as a carbon source to synthesize Ni-Co@C carbon core-shell hydrophobic nanoparticle catalyst via hydrothermal synthesis. The catalyst has a typical core-shell structure and exhibits hydrophobic properties, effectively enhancing its water resistance. However, this catalyst is mainly used for the continuous amination reaction of alcohol hydroxyl groups, and there is no record of its application in the catalytic removal of organosulfur compounds.

[0005] In summary, there is currently no research in this field on the use of ordered core-shell structured desulfurizers for the simultaneous purification of multiple organic sulfur compounds. There is an urgent need to provide an ordered core-shell structured desulfurizer that can efficiently and simultaneously purify and remove multiple organic sulfur compounds. Summary of the Invention

[0006] In view of this, the present invention provides a nitrogen-modified ordered core-shell structured desulfurizer, its preparation method, and its application. The nitrogen-modified ordered core-shell structured desulfurizer provided by the present invention can achieve efficient and simultaneous removal of various organic sulfur compounds, exhibiting good desulfurization effect, long service life, and significant environmental and economic value.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A method for preparing a nitrogen-modified ordered core-shell structured desulfurizer includes the following steps:

[0009] A mixture of carbon source, template agent, acid, water, transition metal salt and silicon source is obtained;

[0010] The mixture was subjected to a hydrothermal synthesis reaction to obtain a desulfurizing agent precursor;

[0011] The desulfurizing agent precursor was calcined in an ammonia-containing atmosphere to obtain a nitrogen-modified ordered core-shell structured desulfurizing agent.

[0012] Preferably, the carbon source includes one or more of carbon nanofibers, carbon nanotubes, carbon nanospheres, and carbon nanosheets;

[0013] The template agent includes one or more of hexadecyltrimethylammonium bromide, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and tetrapropylammonium hydroxide;

[0014] The acid includes one or more of hydrochloric acid, nitric acid, and acetic acid;

[0015] The mass ratio of the template agent to the carbon source is 5-50:1; the mass ratio of the acid to the carbon source is 3-50:1; and the mass ratio of the water to the carbon source is 50-100:1.

[0016] Preferably, the transition metal salt includes one or more of the nitrates, chlorides, and acetates of copper, iron, manganese, nickel, and zinc; the mass ratio of the transition metal salt to the carbon source is 0.1 to 0.5:1.

[0017] Preferably, the silicon source includes one of tetraethyl orthosilicate, fuming silica gel, silica powder, and water glass; the mass ratio of the silicon source to the carbon source is 10 to 100:1.

[0018] Preferably, the method for mixing the carbon source, template agent, acid, water, transition metal salt, and silicon source includes: adding the carbon source, template agent, and acid to water and stirring for a first time to obtain a first mixture; adding the transition metal salt to the first mixture and stirring for a second time to obtain a second mixture; adding the silicon source to the second mixture and stirring for a third time to obtain the mixed liquid; the stirring temperature of the first stirring is 25-50°C, and the stirring time is 1-3 hours; the stirring temperature of the second stirring is 30-60°C, and the stirring time is 0.5-3 hours; the stirring temperature of the third stirring is 30-60°C, and the stirring time is 6-10 hours; the addition rate of the silicon source is 1-10 g / min.

[0019] Preferably, the temperature of the hydrothermal synthesis reaction is 100–150°C, and the reaction time is 8–72 h.

[0020] Preferably, after the hydrothermal synthesis reaction is completed, the process further includes filtering the resulting reaction solution, washing the resulting solid product alternately with water and an organic solvent until the filtrate is neutral, and then drying it; the organic solvent includes one or more of N,N-dimethylformamide, anhydrous ethanol, and isopropanol; the drying temperature is 70-110°C, and the time is 8-36 hours.

[0021] Preferably, the ammonia-containing atmosphere is an ammonia-nitrogen mixed atmosphere, wherein the volume fraction of ammonia in the ammonia-nitrogen mixed atmosphere is 1-10%; the gas flow rate of the ammonia-containing atmosphere is 30-100 mL / min; and the calcination temperature is 400-600℃, and the time is 2-5 h.

[0022] The present invention also provides a nitrogen-modified ordered core-shell structured desulfurizer prepared by the preparation method described above.

[0023] This invention also provides the application of the nitrogen-modified ordered core-shell structured desulfurizer described above in the catalytic removal of organic sulfur.

[0024] This invention provides a method for preparing a nitrogen-modified ordered core-shell desulfurizer, comprising the following steps: mixing a carbon source, a template agent, an acid, water, a transition metal salt, and a silicon source to obtain a mixed solution; subjecting the mixed solution to a hydrothermal synthesis reaction to obtain a desulfurizer precursor; and calcining the desulfurizer precursor in an ammonia-containing atmosphere to obtain a nitrogen-modified ordered core-shell desulfurizer. This invention utilizes a carbon source as the core, and a silicon source and template agent to form a metal-modified silicon-based ordered porous shell, followed by nitrogen modification through calcination in an ammonia-containing atmosphere, ultimately yielding a nitrogen-modified ordered core-shell desulfurizer. Compared with conventional carbon-based desulfurizers, the nitrogen-modified ordered core-shell desulfurizer prepared by this invention has the following advantages:

[0025] (1) Commonly used carbon-based desulfurizers have disordered structures and suffer from uneven distribution of catalytic sites. Therefore, it is often necessary to optimize the pore structure of the catalyst to further improve its activity and selectivity. Ordering the catalyst pore structure exposes more active sites, promotes uniform dispersion of active components on the catalyst surface, and facilitates the full conduct of surface reactions. This invention synthesizes a nitrogen-modified ordered core-shell structure desulfurizer with a large specific surface area by adding a template agent. Nitrogen modification forms an MNC structure (M being a metal) and amino functional groups on the surface of the desulfurizer, effectively improving its chemical adsorption capacity and service life, and providing more possibilities for the industrial application of desulfurizers.

[0026] (2) Conventional core-shell catalysts suffer from problems such as a single pore structure and low selective adsorption capacity. This invention uses a template agent to regulate the pore structure of the shell material, achieving selective removal of organic sulfur from the energy gas. This avoids the competitive adsorption of organic sulfur by water vapor in the gas source, thus improving the catalyst's lifespan. The desulfurization rate can reach 100% under low temperature (≤100℃) conditions. Attached Figure Description

[0027] Figure 1 This is an electron microscope image of the nitrogen-modified ordered core-shell structured desulfurizer of Example 1 of the present invention;

[0028] Figure 2 The removal efficiency of COS and CH3SH by the desulfurizing agents prepared in Examples 1-4 and Comparative Examples 1-3 of this invention. Detailed Implementation

[0029] This invention provides a method for preparing a nitrogen-modified ordered core-shell structured desulfurizer, comprising the following steps:

[0030] A mixture of carbon source, template agent, acid, water, transition metal salt and silicon source is obtained;

[0031] The mixture was subjected to a hydrothermal synthesis reaction to obtain a desulfurizing agent precursor.

[0032] The desulfurizing agent precursor was calcined in an ammonia-containing atmosphere to obtain a nitrogen-modified ordered core-shell structured desulfurizing agent.

[0033] This invention mixes a carbon source, a template agent, an acid, water, a transition metal salt, and a silicon source to obtain a mixed solution. In this invention, the carbon source preferably includes one or more of carbon nanofibers, carbon nanotubes, carbon nanospheres, and carbon nanosheets; the template agent preferably includes one or more of hexadecyltrimethylammonium bromide (CTAB), polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123), and tetrapropylammonium hydroxide (TPAOH); the acid preferably includes one or more of hydrochloric acid, nitric acid, and acetic acid; the hydrochloric acid is preferably concentrated hydrochloric acid, the nitric acid is preferably concentrated nitric acid, and the acetic acid is preferably glacial acetic acid; the mass ratio of the template agent to the carbon source... The preferred ratio is 5-50:1, more preferably 15-30:1; the preferred mass ratio of the acid to the carbon source is 3-50:1, more preferably 5-40:1; in a specific embodiment of the present invention, when the acid is hydrochloric acid, the preferred mass ratio of the acid to the carbon source is 25-50:1; when the acid is nitric acid, the preferred mass ratio of the acid to the carbon source is 3:1; when the acid is acetic acid, the preferred mass ratio of the acid to the carbon source is 35:1; the preferred mass ratio of the water to the carbon source is 50-100:1, more preferably 70-80:1; the preferred water is deionized water.

[0034] In this invention, the transition metal salt preferably includes one or more of the nitrates, chlorides, and acetates of copper, iron, manganese, nickel, and zinc, specifically one or more of copper chloride, ferric nitrate, manganese acetate, zinc acetate, and nickel chloride; when there are multiple transition metal salts, the transition metal salts are preferably manganese acetate and zinc acetate, and the mass ratio of manganese acetate to zinc acetate is preferably 3:2; the mass ratio of the transition metal salt to the carbon source is preferably 0.1 to 0.5:1, more preferably 0.2 to 0.4:1.

[0035] In this invention, the silicon source preferably includes one of tetraethyl orthosilicate, fuming silica gel, silica powder, and water glass; the mass ratio of the silicon source to the carbon source is preferably 10 to 100:1, more preferably 20 to 80:1.

[0036] In this invention, the method for mixing the carbon source, template agent, acid, water, transition metal salt, and silicon source preferably includes: adding the carbon source, template agent, and acid to water and stirring for a first time to obtain a first mixture (denoted as mixed acidic solution A); adding the transition metal salt to the first mixture and stirring for a second time to obtain a second mixture (denoted as mixed solution B); adding the silicon source to the second mixture and stirring for a third time to obtain the mixed liquid (denoted as milky white turbid liquid C); the temperature of the first stirring is preferably 25-50°C, more preferably 30-40°C. The stirring temperature is 0℃, and the stirring time is preferably 1-3 hours, more preferably 2 hours; the second stirring temperature is preferably 30-60℃, more preferably 40-50℃, and the stirring time is preferably 0.5-3 hours, more preferably 1-2.5 hours; the third stirring temperature is preferably 30-60℃, more preferably 40-50℃, and the stirring time is preferably 6-10 hours, more preferably 7-9 hours; the silicon source addition rate is preferably 1-10 g / min, more preferably 2-8 g / min; the third stirring time is calculated from the start of silicon source addition. After the third stirring is completed, a milky white turbid liquid is obtained, which is the final mixed liquid.

[0037] After obtaining the mixed liquid, the present invention performs a hydrothermal synthesis reaction on the mixed liquid to obtain a desulfurizing agent precursor. In the present invention, the temperature of the hydrothermal synthesis reaction is preferably 100-150℃, more preferably 110-140℃, and the reaction time is preferably 8-72h, more preferably 8h, 9h, 16h or 64h; the hydrothermal synthesis reaction is preferably carried out in a reactor. During the hydrothermal synthesis reaction, the silicon source forms an ordered core-shell coating structure on the surface of the carbon source through self-assembly under the action of the template agent. The transition metal enters the silicon source through doping to form a Si-OM structure, and then gradually crystallizes over a certain period of time to form a large-particle precursor.

[0038] After the hydrothermal synthesis reaction is completed, the present invention preferably further includes filtering the obtained reaction solution, washing the obtained solid product alternately with water and an organic solvent until the filtrate is neutral, and then drying; the organic solvent preferably includes one or more of N,N-dimethylformamide, anhydrous ethanol, and isopropanol; the drying is preferably oven drying; the drying temperature is preferably 70-110°C, and the drying time is preferably 8-36 hours. The present invention removes unreacted metal ions and acid from the solid surface by rinsing, which is beneficial for forming a higher purity desulfurizer during the calcination process.

[0039] After obtaining the desulfurizing agent precursor, the present invention calcines the precursor under an ammonia-containing atmosphere to obtain a nitrogen-modified ordered core-shell structured desulfurizing agent. In this invention, the ammonia-containing atmosphere is preferably an ammonia-nitrogen mixed atmosphere, with the volume fraction of ammonia in the ammonia-nitrogen mixed atmosphere preferably being 1-10%, more preferably 4-5%; the gas flow rate of the ammonia-containing atmosphere is preferably 30-100 mL / min, more preferably 50-80 mL / min; the calcination temperature is preferably 400-600℃, more preferably 400℃, 500℃, or 600℃; the calcination time is preferably 2-5 h, more preferably 3-4 h; the calcination is preferably carried out in a tube furnace, during which the template agent decomposes, forming an ordered porous structure. This invention, by calcining under an ammonia-containing atmosphere to nitrogen-modify the surface of the desulfurizing agent, forms an MNC structure (M being a metal) and amino functional groups on the surface, thereby increasing the surface alkaline functional groups of the desulfurizing agent and effectively improving its chemical adsorption capacity and service life.

[0040] This invention also provides a nitrogen-modified ordered core-shell structured desulfurizer prepared by the preparation method described above; the nitrogen-modified ordered core-shell structured desulfurizer includes a core and a shell; the core is a carbon material, and the shell is a nitrogen- and metal-modified ordered porous silicon-based material. In this invention, the desulfurizer has a mesoporous structure, with an average pore size preferably of 3–11 nm, and a specific surface area preferably of 500–750 m². 2 / g.

[0041] The present invention also provides the application of the nitrogen-modified ordered core-shell structured desulfurizer described above in the catalytic removal of organic sulfur; the organic sulfur is preferably carbonyl sulfide (COS) and / or methanethiol (CH3SH); the nitrogen-modified ordered core-shell structured desulfurizer provided by the present invention can achieve efficient simultaneous removal of multiple organic sulfur, especially simultaneous removal of carbonyl sulfide and methanethiol; in a specific embodiment of the present invention, the desulfurization temperature is preferably 30-100℃, more preferably 60℃.

[0042] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0043] In the following examples and comparative examples, the hydrochloric acid used was concentrated hydrochloric acid, the nitric acid was concentrated nitric acid, and the acetic acid was glacial acetic acid.

[0044] Example 1

[0045] 1g of carbon nanosheets, 5g of CTAB, and 25g of hydrochloric acid were added to 100g of deionized water and stirred continuously at 50℃ for 3h to obtain a mixed acidic solution A. 0.2g of copper chloride was added to mixed acidic solution A and stirred continuously at 45℃ for 0.5h to obtain mixed solution B. 30g of tetraethyl orthosilicate was slowly added to mixed solution B and stirred continuously at 30℃ for 8h to form a milky white turbid liquid C. The milky white turbid liquid C was placed in a reactor and hydrothermally synthesized at 110℃ for 72h. The mixture after hydrothermal synthesis was filtered to obtain a solid, which was washed with water and N,N-dimethylformamide until the filtrate was neutral, and then dried at 90℃ for 8h to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was placed in a tube furnace and calcined at 400℃ for 3h under an ammonia atmosphere of 70ml / min (4% nitrogen in ammonia by volume) to finally obtain a nitrogen-modified ordered core-shell structure desulfurizing agent, denoted as desulfurizing agent A. The desulfurizing agent has an average pore size of 3.97 nm and a specific surface area of ​​628 m². 2 / g. Figure 1 The image shows the electron micrograph of the nitrogen-modified ordered core-shell desulfurizer prepared in Example 1. According to... Figure 1 It can be seen that the desulfurizer has a rich pore structure. The shell structure, due to its rich pore structure and small particle size, cannot be independently aggregated and formed. Therefore, it is coated on the core surface in the form of shell particles.

[0046] Example 2

[0047] 1g of carbon nanotubes, 20g of P123, and 3g of nitric acid were added to 50g of deionized water and stirred continuously at 30℃ for 1h to obtain a mixed acidic solution A. 0.4g of ferric nitrate was added to mixed acidic solution A and stirred continuously at 30℃ for 2h to obtain mixed solution B. 10g of fuming silica gel was slowly added to mixed solution B and stirred continuously at 50℃ for 10h to form a milky white turbid liquid C. The milky white turbid liquid C was placed in a reactor and hydrothermally synthesized at 100℃ for 64h. The mixture after the hydrothermal reaction was filtered to obtain a solid, which was washed with water and anhydrous ethanol until the filtrate was neutral. Then, it was dried at 110℃ for 16h to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was placed in a tube furnace and calcined at 500℃ for 5h under an ammonia atmosphere of 30mL / min (1% nitrogen in ammonia solution by volume) to finally obtain a nitrogen-modified ordered core-shell structure desulfurizing agent, denoted as desulfurizing agent B. The desulfurizing agent has an average pore size of 6.05 nm and a specific surface area of ​​531 m². 2 / g.

[0048] Example 3

[0049] 1g of carbon nanospheres, 50g of TPAOH, and 35g of acetic acid were added to 80g of deionized water and stirred continuously at 40℃ for 2h to obtain a mixed acidic solution A. 0.3g of manganese acetate and 0.2g of zinc acetate were added to mixed acidic solution A and stirred continuously at 50℃ for 3h to obtain mixed solution B. 70g of silica powder was slowly added to mixed solution B and stirred continuously at 40℃ for 6h to form a milky white turbid liquid C. The milky white turbid liquid C was placed in a reactor and hydrothermally synthesized at 140℃ for 16h. The mixture after the hydrothermal reaction was filtered to obtain a solid, which was washed with water and isopropanol until the filtrate was neutral. Then, it was dried at 100℃ for 28h to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was placed in a tube furnace and calcined at 550℃ for 2h under an ammonia atmosphere of 55ml / min (10% nitrogen in ammonia solution by volume) to finally obtain a nitrogen-modified ordered core-shell structure desulfurizing agent, denoted as desulfurizing agent C. The desulfurizing agent has an average pore size of 10.16 nm and a specific surface area of ​​517 m². 2 / g.

[0050] Example 4

[0051] 1g of carbon nanofibers, 15g of P123, and 50g of hydrochloric acid were added to 70g of deionized water and stirred continuously at 25℃ for 1.5h to obtain a mixed acidic solution A. 0.1g of nickel chloride was added to mixed acidic solution A and stirred continuously at 60℃ for 1h to obtain mixed solution B. 100g of water glass was slowly added to mixed solution B and stirred continuously at 60℃ for 9h to form a milky white turbid liquid C. The milky white turbid liquid C was placed in a reactor and hydrothermally synthesized at 140℃ for 8h. The mixture after the hydrothermal reaction was filtered to obtain a solid, which was washed with water and anhydrous ethanol until the filtrate was neutral, and then dried at 70℃ for 36h to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was placed in a tube furnace and calcined at 600℃ for 4h under an atmosphere of 100mL / min ammonia (5% nitrogen by volume) to finally obtain a nitrogen-modified ordered core-shell structure desulfurizing agent, denoted as desulfurizing agent D. The desulfurizing agent has an average pore size of 3.24 nm and a specific surface area of ​​736 m². 2 / g.

[0052] Comparative Example 1 (without template agent)

[0053] 1g of carbon nanotubes and 15g of acetic acid were added to 100g of deionized water and stirred continuously at 45℃ for 3h to obtain a mixed acidic solution A. 0.15g of copper acetate was added to mixed acidic solution A and stirred continuously at 60℃ for 2h to obtain mixed solution B. 40g of tetraethyl orthosilicate was slowly added to mixed solution B and stirred continuously at 60℃ for 10h to form a milky white turbid liquid C. The milky white turbid liquid C was placed in a reactor and hydrothermally synthesized at 130℃ for 24h. The mixture after the hydrothermal reaction was filtered to obtain a solid, which was washed with water and isopropanol until the filtrate was neutral, and then dried at 95℃ for 12h to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was placed in a tube furnace and calcined at 550℃ for 4h under an ammonia atmosphere (4% nitrogen by volume) at a flow rate of 80ml / min to finally obtain the desulfurizing agent, denoted as DB-1. The desulfurizing agent has an average pore size of 14.07nm and a specific surface area of ​​172m². 2 / g.

[0054] Comparative Example 2 (No Silicon Source)

[0055] 1g of carbon nanospheres, 25g of P123, and 20g of nitric acid were added to 90g of deionized water and stirred continuously at 30℃ for 2h to obtain a mixed acidic solution A. 0.25g of ferric nitrate was added to mixed acidic solution A and stirred continuously at 50℃ for 1h to obtain mixed solution B. Mixed solution B was placed in a reactor and hydrothermally synthesized at 110℃ for 54h. The mixture after the hydrothermal reaction was filtered to obtain a solid, which was washed with water and anhydrous ethanol until the filtrate was neutral. Then, it was dried at 100℃ for 24h to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was placed in a tube furnace and calcined at 500℃ for 2h under an ammonia atmosphere of 60mL / min (2% nitrogen in ammonia solution) to finally obtain the desulfurizing agent, denoted as DB-2. The desulfurizing agent has an average pore size of 22.37nm and a specific surface area of ​​97m². 2 / g.

[0056] Comparative Example 3 (roasting atmosphere without ammonia)

[0057] 1g of carbon nanofibers, 30g of CTAB, and 8g of hydrochloric acid were added to 85g of deionized water and stirred continuously at 50℃ for 1h to obtain a mixed acidic solution A. 0.4g of manganese chloride was added to mixed acidic solution A and stirred continuously at 40℃ for 3h to obtain mixed solution B. 60g of water glass was slowly added to mixed solution B and stirred continuously at 40℃ for 8h to form a milky white turbid liquid C. The milky white turbid liquid C was placed in a reactor and hydrothermally synthesized at 120℃ for 72h. The mixture after the hydrothermal reaction was filtered to obtain a solid, which was washed with water and N,N-dimethylformamide until the filtrate was neutral. Then, it was dried at 105℃ for 16h to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was placed in a tube furnace and calcined at 600℃ for 3h under a nitrogen atmosphere at 100mL / min to finally obtain the desulfurizing agent, denoted as DB-3. The desulfurizing agent has an average pore size of 16.76nm and a specific surface area of ​​203m². 2 / g.

[0058] Desulfurization activity test:

[0059] The desulfurizing agents prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to activity tests. The activity tests were conducted in a fixed-bed quartz reactor under the following conditions: water vapor content in the gas source was 0.5% vol, COS concentration was 400 ppm, CH3SH concentration was 200 ppm, and the balance was nitrogen, with a space velocity of 20000 h⁻¹. -1 The reaction temperature is 60℃.

[0060] The removal rates of COS and CH3SH in Examples 1-4 and Comparative Examples 1-3 are shown in the figure. Figure 2 Where A-COS represents the removal rate of COS by desulfurizing agent A, and A-CH3SH represents the removal rate of CH3SH by desulfurizing agent A, the meanings of other icons follow the same logic and will not be repeated here. From Figure 2As can be seen from the above, the desulfurization performance of the desulfurizers prepared in Examples 1-4 is far superior to that of Comparative Examples 1-3. Under the above reaction conditions, they can achieve 100% desulfurization efficiency and have a significantly extended service life. This indicates that the nitrogen-modified ordered core-shell structure desulfurizer has a significant effect on the removal of COS and CH3SH.

[0061] In summary, this invention utilizes a carbon source as the core, forms a metal-modified silicon-based ordered porous shell on the surface using a template agent, and then forms an MNC structure (M being a metal) and amino functional groups on the surface through nitrogen modification, ultimately obtaining a nitrogen-modified ordered core-shell desulfurizer for the catalytic removal of organic sulfur. The nitrogen-modified ordered core-shell desulfurizer synthesized in this invention possesses a regular surface structure and abundant pore structure, which is beneficial for the adsorption and catalytic removal of organic sulfur. Nitrogen modification can increase the surface alkaline functional groups of the desulfurizer, effectively improving its chemical adsorption capacity and service life, and providing more possibilities for the industrial application of desulfurizers.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a nitrogen-modified ordered core-shell structured desulfurizing agent for catalytic removal of organic sulfur, characterized in that, Includes the following steps: A carbon source, template agent, acid, water, transition metal salt, and silicon source are mixed to obtain a mixed solution; the acid includes one or more of hydrochloric acid, nitric acid, and acetic acid; the transition metal salt includes one or more of nitrates, chlorides, and acetates of copper, iron, manganese, nickel, and zinc; the mass ratio of the transition metal salt to the carbon source is 0.1~0.5:1; the mass ratio of the silicon source to the carbon source is 10~100:

1. The mixture was subjected to a hydrothermal synthesis reaction to obtain a desulfurizing agent precursor; The desulfurizing agent precursor is calcined in an ammonia-containing atmosphere to obtain a nitrogen-modified ordered core-shell structured desulfurizing agent; the carbon source is one or more of carbon nanofibers, carbon nanotubes, carbon nanospheres, and carbon nanosheets; the ammonia-containing atmosphere is an ammonia-nitrogen mixed atmosphere, and the volume fraction of ammonia in the ammonia-nitrogen mixed atmosphere is 1~10%; the nitrogen-modified ordered core-shell structured desulfurizing agent includes a core and a shell; the core is a carbon material, and the shell is a nitrogen and metal-modified ordered porous silicon-based material.

2. The preparation method according to claim 1, characterized in that, The template agent includes one or more of hexadecyltrimethylammonium bromide, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and tetrapropylammonium hydroxide; The mass ratio of the template agent to the carbon source is 5~50:1; the mass ratio of the acid to the carbon source is 3~50:1; and the mass ratio of the water to the carbon source is 50~100:

1.

3. The preparation method according to claim 1, characterized in that, The silicon source includes one of tetraethyl orthosilicate, fuming silica gel, silica powder, and water glass.

4. The preparation method according to claim 1, characterized in that, The method for mixing carbon source, template agent, acid, water, transition metal salt and silicon source includes: adding carbon source, template agent and acid to water and stirring for a first time to obtain a first mixture; adding transition metal salt to the first mixture and stirring for a second time to obtain a second mixture; adding silicon source to the second mixture and stirring for a third time to obtain the mixed liquid; the temperature of the first stirring is 25~50℃ and the stirring time is 1~3h; the temperature of the second stirring is 30~60℃ and the stirring time is 0.5~3h; the temperature of the third stirring is 30~60℃ and the stirring time is 6~10h; the addition rate of silicon source is 1~10g / min.

5. The preparation method according to claim 1, characterized in that, The hydrothermal synthesis reaction is carried out at a temperature of 100-150℃ for 8-72 hours.

6. The preparation method according to claim 1 or 5, characterized in that, After the hydrothermal synthesis reaction is completed, the process further includes filtering the resulting reaction solution, washing the resulting solid product alternately with water and organic solvent until the filtrate is neutral, and then drying it; the organic solvent includes one or more of N,N-dimethylformamide, anhydrous ethanol and isopropanol; the drying temperature is 70~110℃ and the time is 8~36h.

7. The preparation method according to claim 1, characterized in that, The flow rate of the ammonia-containing atmosphere is 30~100mL / min; the calcination temperature is 400~600℃, and the time is 2~5h.

8. The nitrogen-modified ordered core-shell structured desulfurizer prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the nitrogen-modified ordered core-shell structured desulfurizer according to claim 8 in the catalytic removal of organic sulfur.

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