CN103432897A - Nitrogen-rich porous carbon desulfurizer and preparation method thereof - Google Patents

Abstract

The invention discloses a nitrogen-rich porous carbon desulfurizer and a preparation method thereof. The desulfurizer is composed of porous carbon material pretreated by surface oxidation and nitrogen-containing functional groups fixed on the surface of the porous carbon material by impregnation and sintering, and the mass content of nitrogen element is 0.5-5.0% of the total mass of the desulfurizer. For the preparation of porous carbon desulfurizer, the porous carbon material is first soaked in a strong oxidant solution for surface oxidation pretreatment, and then mixed with a nitrogen-containing compound solution for impregnation, fully impregnated, evaporated to remove the solvent, dried and placed in a high-temperature calciner. Calcination is carried out at 400-1000°C under the protection of inert gas to decompose nitrogen-containing compounds and react with the surface of activated carbon. After fully calcined and cooled, the nitrogen-rich porous carbon desulfurizer is prepared. The surface nitrogen-containing functional group content of the desulfurizer carbon material prepared by the invention is high, and the desulfurization capacity is 1.5-2 times higher than that of the activated carbon desulfurizer whose surface is directly modified with nitrogen without surface oxidation pretreatment.

Description

Nitrogen-rich porous carbon desulfurizer and preparation method thereof

technical field

The invention relates to desulfurizing agent technology, in particular to a porous carbon desulfurizing agent containing abundant nitrogen-containing functional groups on the surface for removing sulfur dioxide from industrial exhaust gas and a preparation method thereof, belonging to the fields of material science and engineering, chemical engineering and environmental protection.

Background technique

China's SO ₂ pollution is very serious, and the SO ₂ emitted into the atmosphere exceeds 20 million tons every year, ranking first in the world. The harmful area of acid rain pollution caused by SO ₂ emissions has reached 30% of the country's land area, which has become an important factor restricting the sustainable development of China's economy and society. Therefore, it is very urgent to increase the control of _SO2 pollution.

The wet flue gas desulfurization technology represented by the limestone-gypsum method is currently the most widely used desulfurization technology in the world. This method uses limestone as an absorbent to absorb _SO2 in the flue gas and generate gypsum as a by-product. However, in practical engineering applications, this desulfurization technology faces problems such as large equipment corrosion and wear, large investment, large output of by-product gypsum, and low utilization value of by-product gypsum.

Carbon-based flue gas desulfurization technology uses porous carbon materials such as granular activated carbon (GAC) or activated carbon fiber (ACF) as desulfurizers, and utilizes the nanopore structure of porous carbon materials to adsorb and catalyze SO ₂ in the flue gas to SO ₃ . The final desulfurizer can be regenerated by washing or heating. Unlike limestone-gypsum desulfurization technology, which produces gypsum by-product, the by-product of carbon-based flue gas desulfurization technology is dilute sulfuric acid (water washing regeneration) or concentrated SO ₂ (heating regeneration), which has high utilization value.

Porous carbon material desulfurizer is the basis of carbon-based flue gas desulfurization technology. Nitrogen function) is very relevant. Increasing the number of nitrogen-containing functional groups on the surface of activated carbon is beneficial to improve its desulfurization activity. However, the current porous carbon materials such as commercial activated carbon have a single surface structure, contain only a very small amount of oxygen-containing functional groups, and usually have no nitrogen-containing functional groups. When porous carbon materials such as ordinary commercial activated carbon are used as desulfurizers for flue gas desulfurization, the desulfurization performance is usually poor.

There are usually two methods for preparing nitrogen-containing porous carbon in the prior art: 1) mixing nitrogen-containing compounds into the production raw materials to embed nitrogen elements in the carbon skeleton; 2) post-processing finished porous carbon such as activated carbon and activated carbon fibers, and Nitrogen-containing functional groups are grafted on the surface of porous carbon.

Nitrogen-containing activated carbon can be obtained by mixing nitrogen-containing compounds into the raw materials for the production of porous carbon materials such as activated carbon, and through carbonization and activation. For example, a method for preparing nitrogen-containing pitch spherical activated carbon is disclosed in the patent document whose application number is 200810035853.3. In the method, nitrogen-containing compounds such as melamine or melamine-formaldehyde resin are mixed into pelletized raw materials such as pitch and naphthalene, and then nitrogen-containing pitch-based spherical activated carbon is prepared through pelletizing, non-melting, carbonization and activation treatments. Another example is the preparation method of a nitrogen-rich activated carbon electrode disclosed in the patent document with the application number of 201110291513.9. This method uses waste wood-based panels containing amino resins as raw materials to prepare nitrogen-containing activated carbon through carbonization and activation processes, and use Electrode material for electric double layer capacitors.

According to the preparation methods disclosed in the patent documents of application numbers 200810035853.3 and 201110291513.9, nitrogen-containing compounds are mixed into the raw materials, and carbonization and activation processes are performed simultaneously with the raw materials for producing activated carbon to prepare nitrogen-containing activated carbon. However, since the activation process is usually required to be carried out at a high temperature above 900°C, the pyrolysis and volatilization of nitrogen-containing compounds is relatively complete, so only a small amount of nitrogen remains in the activated carbon. At the same time, in the nitrogen-containing activated carbon prepared by this method, the nitrogen element is more uniformly embedded in the skeleton of the carbon material, and the nitrogen-containing functions on the surface of the activated carbon are not many. The desulfurization of activated carbon or activated carbon fiber is a process of surface adsorption and catalytic oxidation, and the nitrogen element in the bulk phase does not contribute much to the desulfurization process. Therefore, how to prepare nitrogen-rich porous carbon desulfurizers with abundant nitrogen-containing functional groups on the surface is still very important.

Journal of Environmental Engineering, Volume 5, Issue 4 (2011) disclosed a method of nitrogen modification of activated carbon fibers by impregnating high-temperature grafting method and used for flue gas desulfurization. In this document, activated carbon fibers are soaked in an aqueous solution of melamine, ammonium chloride, and urea, and then heat-treated in a box-type resistance furnace under nitrogen protection after drying. The desulfurization performance of activated carbon fiber after nitrogen modification is improved. However, due to the graphitized structure on the surface of carbon materials such as activated carbon fibers, its surface is hydrophobic and has low reactivity, and it is difficult for nitrogen to graft on the surface of carbon materials such as activated carbon fibers. Therefore, the degree of improvement in the desulfurization performance of activated carbon fibers is limited.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention aims to provide a nitrogen-rich porous carbon material desulfurizer with abundant nitrogen-containing functional groups on the surface and a preparation method thereof, so as to overcome the problems existing in the nitrogen-containing porous carbon material desulfurizer prepared by the prior art. The problem of low content of nitrogen-containing functional groups on the surface of carbon materials.

The basic concept of the present invention is as follows: firstly, carry out surface oxidation pretreatment to porous carbon materials such as commercially available activated carbon and activated carbon fiber, increase the oxygen-containing functional groups on the surface of porous carbon, and improve its surface reactivity; then, the pretreated The porous carbon material is immersed in a solution of nitrogen-containing compound in water or an organic solvent. After soaking for a certain period of time, the solvent is evaporated, so that the nitrogen-containing compound is evenly dispersed in the pores and on the outer surface of the porous carbon; finally, calcined in an inert atmosphere The nitrogen-containing compound is decomposed, and the decomposition product reacts with the surface carbon atoms of the porous carbon at high temperature to form a nitrogen-containing functional group on the surface, and a nitrogen-rich porous carbon desulfurizer is prepared.

The nitrogen-rich porous carbon material desulfurizer provided by the present invention is composed of a porous carbon material pretreated by surface oxidation and a nitrogen-containing functional group fixed on the surface of the porous carbon material through impregnation and sintering, wherein the mass content of nitrogen element is the total amount of the desulfurizer. 0.5~5.0% of the mass. The porous carbon material is preferably granular activated carbon or activated carbon fiber.

The method for preparing the above-mentioned nitrogen-rich porous carbon desulfurizer provided by the present invention comprises the following steps:

(1) Surface oxidation pretreatment: Soak the commercially available porous carbon material in a strong oxidant solution at a temperature not higher than 60°C for surface oxidation pretreatment, increase the oxygen-containing functional groups on the surface of the porous carbon material, and fully oxidize Finally, take it out, wash it with deionized water until the pH value of the washing liquid is 6-7, and then enter the next process after drying;

(2) Impregnation of nitrogen-containing compounds: dissolving nitrogen-containing compounds in a solvent to prepare a solution, uniformly mixing with the porous carbon material obtained by surface oxidation pretreatment in step (1), and fully impregnating to make the nitrogen-containing compounds evenly dispersed in the porous carbon The pores and outer surface of the material are evaporated at a temperature not higher than 100°C to remove the solvent in the porous carbon material impregnated with nitrogen-containing compounds, and then dried to enter the next process. The quality of porous carbon materials and nitrogen-containing compounds The ratio is 1:0.02~3;

(3) High-temperature calcination: put the porous carbon material impregnated with nitrogen-containing compounds obtained in step (2) into a high-temperature calcination furnace, and heat up to 400-1000°C for 0.5-12 hours under the protection of inert gas to decompose the nitrogen-containing compounds and react with the surface of the activated carbon, and prepare a nitrogen-rich porous carbon desulfurizer with rich nitrogen-containing functional groups on the surface after cooling.

The porous carbon material used in step (1) can be granular activated carbon, activated carbon fiber, etc., and the source is not limited. Activated carbon can be mineral activated carbon (such as coal-based activated carbon, pitch-based activated carbon, etc.), wood activated carbon (such as coconut shell activated carbon, apricot shell activated carbon, wood powder carbon, etc.) or activated carbon made of other raw materials (such as waste rubber, waste plastic, Activated carbon made from agricultural waste, etc.); activated carbon fiber can be viscose-based activated carbon fiber, pitch-based activated carbon fiber or polypropylene cyano-based activated carbon fiber, etc. The strong oxidant used in step (1) can be nitric acid, phosphoric acid, or a mixed solution of sulfuric acid and potassium permanganate. Nitric acid with a mass concentration of 20-50% is preferred, and the preparation is more economical.

The nitrogen-containing compound used in step (2) may be dicyandiamine, urea, melamine, or a mixture of any two or more thereof. When a mixture is used, the ratio of each nitrogen-containing compound is not limited. The solvent used to dissolve nitrogen-containing compounds such as urea in step (2) can be water, ethanol, other organic solvents or a mixture of water and organic solvents, and the mixing ratio is not limited if the mixture is used as the solvent. Increasing the proportion of organic solvent can speed up the evaporation rate of the solvent in the drying step. The dissolving temperature of the nitrogen-containing compound in step (2) is from room temperature to 100° C., increasing the dissolving temperature can reduce the amount of water or organic solvent used. In step (2), the mass mixing ratio of nitrogen-containing compounds and porous carbon materials such as activated carbon and activated carbon fiber can be controlled in the range of 1:0.02-3, and the nitrogen content of the prepared nitrogen-rich porous carbon desulfurizer can be determined by this mixing ratio Make adjustments. After the nitrogen-containing compound and the porous carbon are uniformly impregnated in step (2), the temperature for evaporating the solvent is from room temperature to 100°C, preferably controlled within the range of 40-100°C. Increasing the evaporation temperature can save evaporation time, but it is not conducive to the uniform mixing of nitrogen-containing compounds and porous carbon.

The inert atmosphere in step (3) can be realized by feeding a certain amount of inert gas into the high temperature calciner, and the inert gas can be nitrogen, argon or helium. To reduce production costs, nitrogen is preferred. The heating rate can be 1-20°C/min, saving time while ensuring quality, preferably 3-10°C/min. It can be directly raised from room temperature to the target temperature according to a certain heating rate, or can be raised to a certain temperature and kept for a certain period of time, and then the temperature is raised in stages.

The nitrogen-enriched activated carbon and activated carbon fiber desulfurizer prepared according to the present invention were tested by the inventor in a fixed-bed reactor for removing _SO2 from simulated flue gas. The test conditions are: the sulfur dioxide content in the simulated flue gas is 0.3%, the oxygen content is 10%, the water vapor content is 8-20%, the bed temperature is 60-150°C, and the space velocity is 500-3000h ^-1 . When the concentration of sulfur dioxide in the outlet is greater than 0.02%, the evaluation experiment is ended and the desulfurization capacity is calculated.

The present invention has the following technical characteristics and advantages:

(1) The present invention uses commercially available activated carbon or activated carbon fiber as a raw material to prepare a desulfurizer through surface nitrogen doping modification. Before the surface nitrogen doping modification, the reactivity of the carbon surface with the pyrolysis products of nitrogen-containing compounds is improved by pretreatment of the surface of activated carbon or activated carbon fiber by oxidation. The nitrogen-rich porous carbon desulfurizer prepared by the invention is rich in nitrogen-containing functional groups on the surface, and the nitrogen content is between 0.5% and 5%.

(2) The desulfurization agent prepared by the present invention has good desulfurization performance. Compared with the original activated carbon or activated carbon fiber, its desulfurization capacity is increased by 4-10 times; compared with the activated carbon or activated carbon fiber directly modified by surface nitrogen without surface oxidation pretreatment, its desulfurization capacity is increased by 1.5-2 times .

(3) The present invention uses nitrogen-containing functional groups on the surface of porous carbon materials such as activated carbon and activated carbon fibers as active components for desulfurization. At lower temperatures (<150°C), SO ₂ in the flue gas can be catalytically converted to SO ₃ , and SO ₃ then reacts with water vapor in the flue gas to form H ₂ SO ₄ as a by-product. Compared with catalysts with Fe, Cu and other metal oxides as active components as desulfurizers, it has the characteristics of high desulfurization efficiency. At the same time, since the active components do not react with dilute sulfuric acid, the problems of rapid loss of active components and low acid quality caused by metal cations in by-product dilute sulfuric acid are avoided.

(4) The nitrogen-rich porous carbon desulfurizer prepared by the present invention has a wide range of applications. It has a good desulfurization effect on the SO ₂ concentration of 0.01%-0.8% in the flue gas, and the outlet SO ₂ concentration can be lower than 100mg/Nm ³ , and the SO ₂ concentration has a wide range; at the same time, it can be used when the flue gas temperature is 30-150°C Both have good desulfurization effect, and the operating temperature range is wide.

(5) The mechanical strength of the nitrogen-rich porous carbon desulfurizer prepared by the present invention is determined by the strength of the activated carbon or activated carbon fiber used in the preparation process. After the nitrogen-containing compound is impregnated, only high-temperature calcination treatment is required without further activation treatment, and the entire surface modification process will not cause a decrease in the strength of activated carbon or activated carbon fibers.

(6) The application number is 200810035853.3 and other invention patents, which prepare nitrogen-containing or nitrogen-rich porous carbon by mixing nitrogen-containing substances into the raw materials for preparing activated carbon. Compared with them, the present invention directly uses commercially available activated carbon and activated carbon fiber Nitrogen-rich porous carbon desulfurizer materials can be prepared by simple impregnation and calcination as raw materials. The nitrogen-containing functional groups in the nitrogen-rich porous carbon desulfurizer materials are evenly dispersed in the pores and outer surfaces of the porous carbon materials. The nitrogen element can be The invention is effectively utilized, has simple preparation process, strong adaptability and wide application prospect.

Description of drawings

Accompanying drawing 1 is the desulfurization comparison time-efficiency curve chart of the nitrogen-enriched activated carbon fiber prepared with dicyandiamine as nitrogen source and other desulfurizers. The test comparison and evaluation conditions are: the sulfur dioxide content in the simulated flue gas is 0.3%, the oxygen content is 5%, the water vapor content is 10%, the bed temperature is 80°C, and the space velocity is 600h ^-1 .

Accompanying drawing 2 is the desulfurization comparison time-efficiency curve graph of nitrogen-enriched granular activated carbon prepared with melamine as nitrogen source and other desulfurizers; the test comparison evaluation conditions are: the sulfur dioxide content in the simulated flue gas is 0.3%, the oxygen content is 10%, The water vapor content is 10%, the bed temperature is 80°C, and the space velocity is 1800h ^-1 .

Accompanying drawing 3 is the desulfurization comparison time-efficiency curve chart of nitrogen-enriched granular activated carbon prepared with urea as nitrogen source and other desulfurizers. The test comparison and evaluation conditions are: the sulfur dioxide content in the simulated flue gas is 0.3%, the oxygen content is 10%, the water vapor content is 10%, the bed temperature is 80 ℃, and the space velocity is 1800h ^-1 .

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments, the purpose of which is to better understand the content of the present invention rather than limit the content of the present invention.

Example 1

Soak the activated carbon fiber in a nitric acid solution with a mass concentration of 30%, stir it in a constant temperature water bath at 60°C for 2 hours, take it out, rinse the activated carbon fiber with deionized water to pH=6-7, and then dry it in an oven at 105°C overnight . Dissolve 100 grams of dicyandiamide in 200 milliliters of ethanol solution with a mass concentration of 50% to form a dicyandiamide solution. Pour 100 grams of acid-washed activated carbon fibers into the above-mentioned dicyandiamide solution, heat while stirring at 60° C., slowly evaporate ethanol and moisture, and then dry overnight at 105° C. in an oven. Put the activated carbon fiber loaded with dicyandiamide into a high-temperature calcination furnace, under the condition of nitrogen protection, raise the temperature from room temperature to 750°C at a rate of 5°C/min, and keep it at 750°C for 1 hour, then cool Finally, a nitrogen-rich activated carbon fiber desulfurizer with dicyandiamine as a nitrogen source for surface nitrogen doping is obtained.

Elemental analysis shows that its nitrogen content is 4.1%. The desulfurization performance test results are shown in Figure 1, and its desulfurization capacity is 231mg/g.

Comparative example 1

The desulfurization performance test of the original activated carbon fiber is shown in Figure 1, and its breakthrough sulfur capacity is 24.5mg/g.

Comparative example 2

Dissolve 100 grams of dicyandiamide in 200 ml of 50% aqueous ethanol to form a dicyandiamide solution. After soaking 100 grams of activated carbon fibers in the above-mentioned dicyandiamide solution for 24 hours, heat at 60° C. to slowly evaporate ethanol and moisture, and then dry overnight at 105° C. in an oven. Put the activated carbon loaded with dicyandiamide into a high-temperature calcination furnace, and raise the temperature from room temperature to 750°C at a rate of 5°C/min under nitrogen protection, and keep it at 750°C for 1 hour. After cooling A nitrogen-rich activated carbon fiber desulfurizer with dicyandiamine as a nitrogen source for surface nitrogen doping is obtained.

Elemental analysis shows that its nitrogen content is 3.1%. The desulfurization performance test results are shown in Figure 1, and its desulfurization capacity is 148mg/g.

Example 2

Soak 10-20 mesh granular activated carbon in a nitric acid solution with a mass concentration of 20%, and stir in a constant temperature water bath at 60°C for 3 hours. The acid-washed granular activated carbon was rinsed with deionized water to pH=6-7, and then dried overnight in an oven at 105°C. Dissolve 5 grams of melamine in 100 milliliters of water to make a melamine solution. Pour 30 grams of acid-washed 10-20 mesh granular activated carbon into the above-mentioned melamine solution, heat while stirring at 60°C, slowly evaporate the water, and then dry in an oven at 105°C overnight. The granular activated carbon loaded with melamine was placed in a high-temperature calciner, and under the condition of nitrogen protection, the temperature was raised from room temperature to 800 °C at a heating rate of 5 °C/min, and kept at 800 °C for 1 hour. After cooling, the following Nitrogen-rich granular activated carbon desulfurizer with melamine as nitrogen source and surface nitrogen doping.

Elemental analysis shows that its nitrogen content is 3.5%. The desulfurization performance test results are shown in Figure 2, and its breakthrough sulfur capacity is 393mg/g.

Comparative example 3

The 10-20 mesh raw granular activated carbon was tested for desulfurization performance, the results are shown in Figure 2, and its breakthrough sulfur capacity was 68mg/g.

Comparative example 4

Dissolve 5 grams of melamine in 100 milliliters of water to make a melamine solution. Pour 30 grams of 10-20 mesh granular activated carbon into the above melamine solution, heat while stirring at 60°C, slowly evaporate the water, and then dry in an oven at 105°C overnight. Put the activated carbon loaded with melamine into a high-temperature calcination furnace, under the condition of nitrogen protection, raise the temperature from room temperature to 800°C at a heating rate of 5°C/min, and keep it at 800°C for 1 hour, and obtain melamine after cooling. Nitrogen-enriched granular activated carbon desulfurizer with surface nitrogen doping as nitrogen source.

Elemental analysis shows that its nitrogen content is 2.6%. The desulfurization performance test results are shown in Figure 2, and its breakthrough sulfur capacity is 255mg/g.

Example 3

Soak 10-20 mesh granular activated carbon in a nitric acid solution with a mass concentration of 50%, and react at 60°C for 1 hour. The acid-washed granular activated carbon was rinsed with deionized water to pH=6-7, and then dried overnight in an oven at 105°C. Dissolve 200 grams of urea in 1000 milliliters of 50% ethanol aqueous solution to form a urea solution. Pour 100 grams of acid-washed granular activated carbon into the above-mentioned urea solution, heat while stirring at 60°C, slowly evaporate ethanol and water, and then dry in an oven at 105°C overnight. The activated carbon loaded with urea was placed in a high-temperature calciner, and under the condition of nitrogen protection, the temperature was raised from room temperature to 850 °C at a heating rate of 5 °C/min, and kept at 850 °C for 1 hour. After cooling, urea was obtained. Nitrogen-enriched granular activated carbon desulfurizer with surface nitrogen doping as nitrogen source.

Elemental analysis shows that its nitrogen content is 3.7%. The desulfurization performance test results are shown in Figure 3, and its desulfurization capacity is 208mg/g.

Comparative example 5

Dissolve 200 grams of urea in 1000 milliliters of 50% aqueous ethanol to form a urea solution. Pour 100 grams of 10-20 mesh granular activated carbon into the above urea solution, heat while stirring at 60°C, slowly evaporate ethanol and water, and then dry in an oven at 105°C overnight. Put the activated carbon loaded with urea into a high-temperature calcination furnace, under the condition of nitrogen protection, raise the temperature from room temperature to 750°C at a heating rate of 5°C/min, and keep it at 750°C for 1 hour, and obtain urea after cooling. Nitrogen-enriched granular activated carbon desulfurizer with surface nitrogen doping as nitrogen source.

Elemental analysis shows that its nitrogen content is 3.1%. The desulfurization performance test results are shown in Figure 3, and its desulfurization capacity is 97mg/g.

Example 4

Soak 10-20 mesh granular activated carbon in a phosphoric acid solution with a mass concentration of 30%, and react at 60°C for 2 hours. The acid-washed granular activated carbon was rinsed with deionized water to pH=6-7, and then dried overnight in an oven at 105°C. Dissolve 100 grams of urea in 1000 ml of water to make a urea solution. Pour 100 grams of acid-washed 10-20 mesh granular activated carbon into the above urea solution, heat while stirring at 60°C, slowly evaporate the water, and then dry it in an oven at 105°C overnight. Put the activated carbon loaded with urea into a high-temperature calcination furnace, under the condition of nitrogen protection, raise the temperature from room temperature to 850°C at a rate of 5°C/min, and keep it at 850°C for 1 hour, and obtain nitrogen-enriched Granular activated carbon desulfurizer.

Example 5

Soak 10-20 mesh granular activated carbon in 150 ml of concentrated sulfuric acid with a mass concentration of 98%, slowly add 18 g of potassium permanganate under ice bath stirring, react for 1 hour under ice bath, and then react for 1 hour at 35°C. The granular activated carbon after surface oxidation treatment was rinsed with deionized water to pH = 6-7, and then dried overnight in an oven at 105°C. Dissolve 100 grams of urea in 1000 ml of water to make a urea solution. Pour 100 grams of 10-20 mesh activated carbon after surface oxidation treatment into the above urea solution, heat while stirring at 60°C, slowly evaporate the water, and then dry in an oven at 105°C overnight. Put the activated carbon loaded with urea into a high-temperature calcination furnace, under the condition of nitrogen protection, raise the temperature from room temperature to 800°C at a heating rate of 5°C/min, and keep it at 800°C for 1 hour, and obtain nitrogen-enriched Granular activated carbon desulfurizer.

Claims (10)

1. A nitrogen-rich porous carbon desulfurizer is characterized in that it is made of porous carbon material after surface oxidation pretreatment and a nitrogen-containing functional group fixed on the surface of the porous carbon material through impregnation and sintering, wherein the mass content of nitrogen element is 0.5-5.0% of the total mass of desulfurizer. 2. The nitrogen-rich porous carbon desulfurizer according to claim 1, wherein the porous carbon material is granular activated carbon or activated carbon fiber. 3. the method for preparing the described nitrogen-rich porous carbon desulfurizer of claim 1 or 2, comprises the steps: (1) Surface oxidation pretreatment: Soak the commercially available porous carbon material in a strong oxidant solution for surface oxidation pretreatment at no higher than 60°C to increase the oxygen-containing functional groups on the surface of the porous carbon material, and take it out after full oxidation treatment , rinse with deionized water until the pH of the washing solution is 6-7, and then enter the next process after drying; (2) Impregnation of nitrogen-containing compounds: dissolving nitrogen-containing compounds in a solvent to prepare a solution, uniformly mixing with the porous carbon material obtained through oxidation pretreatment in step (1), and fully impregnating to make the nitrogen-containing compound evenly dispersed in the porous carbon material The pores and outer surface of the porous carbon material impregnated with nitrogen-containing compounds are evaporated at a temperature not higher than 100°C to remove the solvent in the porous carbon material impregnated with nitrogen-containing compounds, and then dried to enter the next process. The mass ratio of porous carbon materials to nitrogen-containing compounds 1: 0.02~3; (3) High-temperature calcination: put the porous carbon material impregnated with nitrogen-containing compounds obtained in step (2) into a high-temperature calcination furnace, and heat up to 400-1000°C for 0.5-12 hours under the protection of inert gas to decompose the nitrogen-containing compounds and react with the surface of the activated carbon, and prepare a nitrogen-rich porous carbon desulfurizer with rich nitrogen-containing functional groups on the surface after cooling. 4. The method for preparing the nitrogen-rich porous carbon desulfurizer according to claim 3, wherein the strong oxidizing agent is selected from nitric acid, phosphoric acid, or a mixed solution of sulfuric acid and potassium permanganate. 5. The method for preparing the nitrogen-rich porous carbon desulfurizer according to claim 4, wherein the strong oxidizing agent is nitric acid having a mass concentration of 20-50%. 6. The method for preparing the nitrogen-rich porous carbon desulfurizer according to claim 3, wherein the nitrogen-containing compound is selected from the group consisting of dicyandiamide, urea and melamine. 7. The method for preparing the nitrogen-rich porous carbon desulfurizer according to claim 3, wherein the solvent is water, ethanol, other organic solvents or a mixture of water and organic solvents. 8. The method for preparing a nitrogen-rich porous carbon desulfurizer according to any one of claims 3 to 7, wherein the porous carbon material impregnated with a nitrogen-containing compound is evaporated to remove the solvent at 40-100°C, and at 105- Dry at 150°C. 9. The method for preparing a nitrogen-rich porous carbon desulfurizer according to any one of claims 3 to 7, characterized in that the calcination is heated up to 400-1000°C at a heating rate of 1-20°C/min. 10 . The method for preparing the nitrogen-rich porous carbon desulfurizer according to claim 9 , wherein the calcination is heated to 400-1000° C. at a heating rate of 3-10° C./min. 11 .

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