Preparation method of nitrogen and phosphorus doped activated carbon

Abstract

The present invention relates to the technical field of hydrogen sulfide treatment, and discloses a method for preparing nitrogen-phosphorus doped activated carbon with excellent selective oxidation catalytic effect on hydrogen sulfide. The method for preparing nitrogen-phosphorus doped activated carbon comprises the steps of: heat-treating a mixture containing a biomass raw material, a pyridine nitrogen source, a pyrrole nitrogen source, and an oxidant solution to obtain a first precursor; annealing the first precursor under an inert atmosphere to obtain a second precursor; mixing the second precursor, an activator, a binder, and a dispersant, and then extruding the mixture into a blank; carbonizing the blank under an inert atmosphere to obtain a carbonized body; activating the carbonized body under an activating gas atmosphere to obtain an activated body; immersing the activated body in a solution containing a phosphorus-containing precursor, collecting the solid after the immersion is completed, and drying the solid to obtain a third precursor; calcining the third precursor in an inert atmosphere to obtain nitrogen-phosphorus doped activated carbon.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen sulfide treatment, and in particular to a method for preparing nitrogen-phosphorus doped activated carbon. Background Art

[0002] Hydrogen sulfide is a highly toxic compound and an important resource. It is usually associated or by-produced in natural gas extraction, oil refining and coal chemical processes. The elimination and resource utilization of hydrogen sulfide is a long-term issue faced by industries such as natural gas extraction, oil refining, and coal chemical industry. It is an important research topic with a history of 100 years. The current high-temperature oxidation Claus process eliminates hydrogen sulfide by oxidizing it into sulfur and water, but the process emits a large amount of sulfur-containing compound tail gas, which often requires further secondary treatment, or even a multi-step Claus process, in order to completely eliminate sulfur-containing pollutants.

[0003] The commonly used hydrogen sulfide selective oxidation catalysts in industry are metal oxides, such as Fe2O3, V2O5, TiO2 and Cr2O3. These metal oxide catalysts have shortcomings during use, such as: Fe2O3 catalysts have excessive oxygen demand; vanadium and chromium-based catalysts are non-environmentally friendly oxides; TiO2-based catalysts are easily deactivated in the presence of water vapor. In view of the shortcomings of the above-mentioned metal oxide catalysts, it is urgent to develop an environmentally friendly, highly active and highly stable non-metallic desulfurization catalyst that can replace metal oxide catalysts.

[0004] Activated carbon materials have attracted more and more attention as a promising metal-free catalyst in the selective oxidation of hydrogen sulfide due to their rich pore structure, controllable surface functions, excellent regeneration ability and anti-poisoning ability. However, pure activated carbon has a poor catalytic effect on the selective oxidation of hydrogen sulfide. Chinese invention patent CN115159522B and Chinese invention patent application CN112225127A both disclose a nitrogen-phosphorus co-doped activated carbon, which are both used as electrode materials and have not yet been applied in the field of hydrogen sulfide treatment. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing nitrogen-phosphorus-doped activated carbon having excellent catalytic effect on the selective oxidation of hydrogen sulfide.

[0006] In order to achieve the above object, the present invention provides a method for preparing nitrogen and phosphorus doped activated carbon, and the technical scheme is as follows:

[0007] The preparation method of nitrogen and phosphorus doped activated carbon comprises the following steps:

[0008] Heat-treating a mixture containing a biomass raw material, a pyridinic nitrogen source, a pyrrolic nitrogen source, and an oxidant solution, and collecting a solid after the heat treatment is completed to obtain a first precursor;

[0009] annealing the first precursor under an inert atmosphere to obtain a second precursor;

[0010] The second precursor, the activator, the binder and the dispersant are mixed and then extruded to obtain a green body;

[0011] Carrying out carbonization treatment on the green body in an inert atmosphere to obtain a carbonized body;

[0012] Activating the carbonized body in an activation gas atmosphere to obtain an activated body;

[0013] The activated body is immersed in a solution containing a phosphorus-containing precursor, and after the immersion is completed, a solid is collected and dried to obtain a third precursor;

[0014] The third precursor is calcined in an inert atmosphere to obtain nitrogen and phosphorus doped activated carbon.

[0015] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon:

[0016] The biomass raw material is fresh bamboo dried at 90-110° C. for 6-10 hours;

[0017] The mixture also contains at least one of PVP, CTAB, SDS, PEG, PAA, sodium citrate, and sodium gluconate;

[0018] The pyridinic nitrogen source is at least one of melamine, pyridine, aniline and pyrazine;

[0019] The pyrrolic nitrogen source is at least one of urea, melamine and polypyrrole;

[0020] The oxidant is any one of potassium permanganate, potassium ferrate and hydrogen peroxide.

[0021] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon: the heat treatment is heating at 160-200° C. for 8-24 hours.

[0022] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon: the annealing treatment is annealing at 700-900° C. for 1-3 hours.

[0023] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon:

[0024] The activator is potassium carbonate and / or potassium hydroxide;

[0025] The adhesive is at least one of starch, cellulose and molasses; the starch is corn starch and / or cassava starch; the cellulose is sodium carboxymethyl cellulose and / or hydroxypropyl methyl cellulose; the molasses is cane molasses and / or beet molasses;

[0026] The dispersant is water.

[0027] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon: the carbonization treatment is carbonization at 600-800° C. for 1-3 hours.

[0028] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon: the activation treatment is activation at 700-900° C. for 1-3 hours, and the activation gas atmosphere is water vapor.

[0029] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon: the phosphorus-containing precursor is any one of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and ammonium hydrogen phosphate.

[0030] As a further improvement of the above-mentioned preparation method of nitrogen and phosphorus doped activated carbon: the calcination treatment is calcined at 350-500°C for 0.5-2 hours.

[0031] The preparation method of nitrogen and phosphorus doped activated carbon of the present invention has the following advantages:

[0032] (1) Biomass raw materials such as bamboo have a high lignin content, and lignin is more stable than cellulose and hemicellulose. The present invention uses the amino group in the nitrogen source to react with the carbonyl group in the biochar to undergo the Maillard reaction, so that the nitrogen remains in the carbon skeleton; at the same time, in the weakly alkaline or alkaline environment provided by the nitrogen source, an oxidant is used at a relatively low temperature (160-200°C) to destroy the stubborn lignin, and lignin has a three-dimensional cross-linked structure, which is decomposed by the oxidant to form interconnected mesopores, thereby increasing the mesopore content. The nitrogen atoms in the activated carbon prepared by this method are evenly distributed, and most of them are structural nitrogen, which has good stability. At the same time, the oxidant can promote the oxidative depolymerization of hemicellulose and cellulose to generate by-products such as organic acids, furfural, and catechol. The by-products in the activation stage can further undergo a violent decomposition reaction with the oxidant, releasing a large amount of gas (such as carbon dioxide and water vapor), which reacts with the carbon skeleton at high temperature to form micropores and mesopores.

[0033] (2) Since the electronegativity of nitrogen atoms is higher than that of carbon atoms, the lone pair of electrons of carbon atoms are easily captured by nitrogen atoms, resulting in the nitrogen atoms being negatively charged, while the carbon atoms adjacent to the nitrogen atoms are positively charged. Negatively charged nitrogen atoms promote the formation of alkaline conditions and the adsorption of hydrogen sulfide by interacting with the positively charged hydrogen atoms of water or hydrogen sulfide. The alkaline conditions formed can not only further promote the dissociation of hydrogen sulfide into HS -The positively charged carbon atom adsorbs oxygen with an extra lone pair of electrons, promoting the chemical adsorption of oxygen. The chemically adsorbed oxygen is then activated into superoxide radicals (·O2 - ), O2 - HS that can be oxidatively dissociated - Therefore, the present invention changes the charge distribution of activated carbon by nitrogen doping, improves the alkalinity of the activated carbon surface for decomposing hydrogen sulfide and the activity of activating oxygen, thereby enhancing the desulfurization activity of the activated carbon and improving the desulfurization efficiency.

[0034] (3) The present invention introduces pyridinic nitrogen and pyrrolic nitrogen through pyridinic nitrogen sources and pyrrolic nitrogen sources. The nitrogen element has diversity, so that the surface of the activated carbon has different adsorption sites at the same time, which enhances the adsorption capacity of gas molecules such as hydrogen sulfide. In addition, the present invention promotes the Maillard reaction between the amino group in the nitrogen source and the carbonyl group in the biochar through the oxidant, thereby improving the nitrogen doping efficiency; on the other hand, by adding an activator to the blank, the activation temperature can be reduced, thereby avoiding the conversion of nitrogen-containing species into inactive graphite nitrogen and increasing the content of pyridinic nitrogen and pyrrolic nitrogen. Therefore, the present invention reduces the decomposition temperature of lignin through the combined action of the oxidant and the activator, so that the nitrogen-containing species are converted into pyridinic nitrogen and pyrrolic nitrogen with higher activity as much as possible, thereby improving the desulfurization activity of the activated carbon.

[0035] (4) The present invention introduces phosphorus doping into activated carbon. The introduced phosphorus groups interact with the pyridine nitrogen sites as the reaction active centers. This interaction can inhibit the adsorption and activity of oxygen molecules on the active sites, thereby avoiding the occurrence of over-oxidation, improving the selectivity of the product sulfur, and promoting the stable formation of elemental sulfur. At the same time, phosphorus doping helps to improve the thermal stability and antioxidant properties of activated carbon, making it more durable in high temperature environments. In addition, by calcining the third precursor under an inert atmosphere, the phosphorus doping sites are further fixed, reducing the loss of phosphorus during use.

[0036] (5) The multi-stage heat treatment designed by the present invention (including heat treatment, annealing, carbonization and activation treatment) allows the internal pore structure of the activated carbon to be fully developed while ensuring the stability of the carbon skeleton. These steps not only increase the specific surface area and structural stability of the activated carbon, but also optimize the pore size distribution, so that it has better selective adsorption capacity for gas molecules of different sizes. Among them, after the nitrogen source and the oxidant act together, high-temperature annealing treatment is further carried out at high temperature, which can fix nitrogen at high temperature and repair defects in the carbon skeleton, so that the mechanical strength and chemical stability of the activated carbon during use can be improved. After the activation treatment obtains an activated body with well-developed pores, phosphorus doping is carried out, which helps to increase the number of acidic sites and thus improve sulfur selectivity.

[0037] (6) Adding an activator to the green body can promote the formation of pores. Activation treatment under a water vapor atmosphere can effectively open the pore structure of the material. Thus, the specific surface area and micropore content of the activated carbon can be increased by the combined activation pore formation of the activator and water vapor, and an activated carbon with a developed pore structure and a large specific surface area can be obtained. Among them, the developed pore structure is conducive to the mass transfer of reactants and products, allowing the reactants to quickly contact the active sites and avoid the solid products from quickly blocking the pores. The large specific surface area can provide abundant active sites, which can increase the collision probability of the reactants and the active sites, thereby enhancing the adsorption capacity of hydrogen sulfide and promoting the rapid catalytic oxidation of hydrogen sulfide.

[0038] It can be seen that the preparation method of nitrogen-phosphorus doped activated carbon of the present invention breaks the traditional nitrogen-phosphorus doping process, and is combined with the existing biomass activated carbon preparation process (primary carbonization-molding-secondary carbonization-activation), providing a new simple method for preparing non-metallic desulfurization catalysts. The prepared nitrogen-phosphorus co-doped activated carbon has excellent physical and chemical properties and excellent desulfurization performance, and is extremely practical in the technical field of hydrogen sulfide control.

[0039] The following is a further description of the embodiments of the invention provided in this specification in conjunction with the accompanying drawings and specific implementation methods. Additional aspects and advantages of the embodiments of the invention provided in this specification will be partially given in the following description, and partially will become apparent from the following description, or will be understood through the practice of the embodiments of the invention provided in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings that constitute part of the embodiments of the inventions provided in this specification are used to assist in understanding the embodiments of the inventions provided in this specification. The contents provided in the drawings and their related descriptions in the embodiments of the inventions provided in this specification can be used to explain the embodiments of the inventions provided in this specification, but do not constitute improper limitations on the embodiments of the inventions provided in this specification.

[0041] Figure 1 This is the XPS spectrum of N1s of the activated carbon of Example 1 of the present invention.

[0042] Figure 2 This is the XPS spectrum of N1s of the activated carbon of Example 2 of the present invention.

[0043] Figure 3 This is the XPS spectrum of N1s of the activated carbon of Control Example 5 of the present invention.

[0044] Figure 4 It is a schematic structural diagram of the desulfurization performance evaluation device of the present invention. DETAILED DESCRIPTION

[0045] The following is a clear and complete description of the embodiments of the inventions provided in this specification in conjunction with the accompanying drawings. A person of ordinary skill in the art will be able to implement the embodiments of the inventions provided in this specification based on these descriptions. Before describing the embodiments of the inventions provided in this specification in conjunction with the accompanying drawings, it should be particularly noted that:

[0046] The technical solutions and technical features provided in each part of the embodiments of the invention provided in this specification, including the following description, may be combined with each other if there is no conflict.

[0047] In addition, the embodiments of the embodiments of the inventions provided in this specification involved in the following description are generally only a partial embodiment of the embodiments of the inventions provided in this specification rather than all the embodiments. Therefore, based on the embodiments of the embodiments of the inventions provided in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative work should fall within the scope of protection of the embodiments of the inventions provided in this specification.

[0048] Regarding the terms and units in the embodiments of the inventions provided in this specification: The terms "including", "comprising", "having" and any variations thereof in the descriptions and claims of the embodiments of the inventions provided in this specification and in the related parts are intended to cover non-exclusive inclusions. In addition, other relevant terms and units in the embodiments of the inventions provided in this specification can be reasonably interpreted based on the relevant contents of the embodiments of the inventions provided in this specification.

[0049] Example 1: The preparation method of nitrogen and phosphorus doped activated carbon in this example comprises the following steps:

[0050] (1) A mixture containing a biomass raw material, a pyridinic nitrogen source, a pyrrolic nitrogen source, and a hydrogen peroxide solution (mass fraction of 30%) is heated at 190° C. for 12 hours, and after the heat treatment is completed, a solid is collected to obtain a first precursor; the biomass raw material is fresh bamboo dried at 100° C. for 8 hours; the pyridinic nitrogen source and the pyrrolic nitrogen source are both melamine; and the mass ratio of hydrogen peroxide to the biomass raw material is 0.6.

[0051] (2) Annealing the first precursor at 800° C. for 2 hours in an inert atmosphere to obtain a second precursor.

[0052] (3) The second precursor, potassium carbonate, a binder and a dispersant are mixed and extruded to obtain a green body; the mass ratio of potassium carbonate to the second precursor is 0.5; the binder is sugar cane molasses, and the mass ratio of sugar cane molasses to the second precursor is 0.4; the dispersant is water, and 30 mL of water is added for every 100 g of the second precursor.

[0053] (4) The green body was carbonized at 800°C for 2 hours under an inert atmosphere to obtain a carbonized body.

[0054] (5) The carbonized body was activated at 800°C for 2 hours in a water vapor atmosphere to obtain an activated body.

[0055] (6) immersing the activated product in a diammonium hydrogen phosphate solution (5% by mass), collecting the solid after immersion for 1 hour, and drying the solid to obtain a third precursor;

[0056] (7) The third precursor was calcined at 450° C. for 1 hour in a nitrogen atmosphere to obtain nitrogen-phosphorus doped activated carbon.

[0057] Example 2: Compared with Example 1, the preparation method of nitrogen-phosphorus doped activated carbon in this example is different in that: the mixture also contains PVP solution (mass fraction is 2%), and the mass ratio of PVP to biomass raw material is 0.01.

[0058] Example 3: Compared with Example 1, the preparation method of nitrogen-phosphorus doped activated carbon in this example is different in that the pyridinic nitrogen source is pyridine, the pyrrolic nitrogen source is urea, and the mass ratio of pyridine to urea is 1:1.

[0059] Example 4: Compared with Example 1, the preparation method of nitrogen and phosphorus doped activated carbon in this example is different in that the oxidant is potassium permanganate solution, the activator is potassium hydroxide, and the phosphorus-containing precursor is diammonium phosphate.

[0060] Control Example 1: Compared with Example 1, the preparation method of nitrogen-phosphorus doped activated carbon in this control example is different in that no nitrogen source is used.

[0061] Control Example 2: Compared with Example 1, the preparation method of nitrogen-phosphorus doped activated carbon in this control example is different in that only pyridine is used as the nitrogen source.

[0062] Control Example 3: Compared with Example 1, the preparation method of nitrogen-phosphorus doped activated carbon in this control example is different in that only urea is used as the nitrogen source.

[0063] Comparative Example 4: Compared with Example 1, the preparation method of nitrogen-phosphorus doped activated carbon in this comparative example is different in that only diphenylamine is used as the nitrogen source.

[0064] Control Example 5: Compared with Example 1, the preparation method of nitrogen and phosphorus doped activated carbon in this control example is different in that no oxidant is used.

[0065] Control Example 6: Compared with Example 1, the preparation method of nitrogen and phosphorus doped activated carbon in this control example is different in that no activator is used.

[0066] Comparative Example 7: Compared with Example 1, the preparation method of nitrogen-phosphorus-doped activated carbon in this comparative example is different in that step (6) and step (7) are not performed, and the activated body is the final activated carbon.

[0067] Then the catalytic performance of the activated carbons of Examples 1-4 and Comparative Examples 1-7 was tested. The test results are shown in Table 1.

[0068]

[0069] As can be seen from Table 1, the various indicators of the activated carbon of Examples 1-4 are excellent. The XPS spectra of N1s of the activated carbon of Examples 1-2 obtained by X-ray photoelectron spectroscopy (XPS) testing are as follows: Figure 1-2 As shown, the total nitrogen content of the activated carbon of Example 1 is 7.02%, of which the contents of pyridinic nitrogen, pyrrolic nitrogen and graphitic nitrogen are 56.3%, 34.2% and 9.5%, respectively. The total nitrogen content of the activated carbon of Example 2 is 7.74%, of which the contents of pyridinic nitrogen, pyrrolic nitrogen and graphitic nitrogen are 59.1%, 34.6% and 6.4%, respectively, indicating that the nitrogen element mainly exists in the form of pyridinic nitrogen and pyrrolic nitrogen, which helps to show high catalytic activity. Among them, the various indicators of Example 2 are better than those of Example 1, indicating that adding a small amount of PVP to the mixture can promote the introduction of nitrogen elements and the formation of pyridinic nitrogen and pyrrolic nitrogen.

[0070] In addition, the specific surface area, total pore volume and average pore diameter of the activated carbon of Example 1 were 1371 m 2 / g, 0.746cm 3 / g, 2.18nm, the specific surface area, total pore volume and average pore diameter of the activated carbon in Example 2 are 1382m 2 / g, 0.732cm 3 / g, 2.12nm.

[0071] The various indicators of Control Example 1 are significantly weaker than those of Example 1, indicating that nitrogen doping can significantly improve the desulfurization activity of activated carbon. Different nitrogen sources were selected in Control Examples 2-4, and the changes in the indicators showed that a suitable nitrogen source is particularly important for desulfurization performance; among them, Control Example 4 selected a neutral nitrogen source, which resulted in a significant decrease in various indicators, indicating that the activated carbon prepared under alkaline conditions has better desulfurization activity.

[0072] Comparative Example 5 does not use an oxidant. The XPS spectrum of N1s of the activated carbon of Comparative Example 5 obtained by XPS analysis is as follows: Figure 3 As shown in the figure, there is no characteristic peak of pyrrolic nitrogen, and the content of graphitic nitrogen is as high as 62.0%, which leads to a significant reduction in the sulfur generation rate.

[0073] The control example 6 did not use an activator. The specific surface area, total pore volume and average pore diameter of the activated carbon in the control example 6 were 620 m 2 / g, 0.284cm 3 / g, 1.83nm, the specific surface area and total pore volume are significantly reduced, which leads to a significant decrease in the sulfur generation rate.

[0074] Since no phosphorus was doped in Control Example 7, the sulfur selectivity dropped sharply, indicating that the high sulfur selectivity of Examples 1-4 benefited from phosphorus doping modification.

[0075] The schematic diagram of the structure of the device used to evaluate the desulfurization performance of the above activated carbon is as follows: Figure 4 As shown, nitrogen and oxygen are mixed in a gas mixing bottle, then humidified by a humidifier and mixed with H2S, and then flow into a reactor (with an inner diameter of 29 cm) loaded with a desulfurization catalyst (i.e., activated carbon). Test conditions: bed temperature of 190°C, test air velocity of 3000h -1 , H2S concentration is 1%, oxygen concentration is 1vol%, water vapor content is 2vol%, and the rest is nitrogen. Exhaust gas concentration test: The concentrations of oxygen and sulfur dioxide are tested using Gasboard-3000 flue gas analyzer (Hubei Ruiyi Automatic Control System Co., Ltd.), and the concentration of hydrogen sulfide is tested using HF-901 gas chromatograph (Shandong Huifen Instrument Co., Ltd.).

[0076] Hydrogen sulfide conversion rate X H2S , Sulfur selectivity S s , sulfur generation rate λ cat The calculation formulas are as follows:

[0077]

[0078] In the formula, F and F 0 represents the gas inlet flow rate and outlet flow rate respectively; C H2S and C SO2 Respectively represent the concentrations of hydrogen sulfide and sulfur dioxide (inlet represents the inlet concentration, outlet represents the outlet concentration); m cat Indicates the mass of the catalyst, its unit is kg cat ; g H2S It is the unit of mass of hydrogen sulfide.

[0079] The surface element analysis of activated carbon was carried out by X-ray photoelectron spectrometer (Thermo ESCALAB 250XI), with the excitation source being a monochromatic Al target and the power being 120 W. The basic vacuum during the analysis was 3×10 -9mbar. The binding energy of the measured elements was calibrated using the carbon C1s peak 284.8eV. The element XPS spectra were processed using Avantage5.9922 software, and the relative content of atoms on the sample surface was calculated based on the peak area.

[0080] The specific surface area and pore structure of activated carbon were analyzed by a high-performance specific surface and micropore analyzer (BSD-PM2). The specific surface area of ​​the sample was calculated by the Brunauer-Emmett-Teller (BET) method. The total pore volume and pore size distribution were analyzed by the density functional theory (DFT) model. Before the test, the sample was pretreated by vacuum degassing at a degassing temperature of 120°C and a degassing time of 12 hours.

[0081] The above is a description of the relevant contents of the embodiments of the inventions provided in this specification. Based on these descriptions, a person of ordinary skill in the art will be able to implement the embodiments of the inventions provided in this specification. Based on the above contents of the embodiments of the inventions provided in this specification, all other preferred implementations and embodiments obtained by a person of ordinary skill in the art without making any creative work shall fall within the scope of protection of the embodiments of the inventions provided in this specification.

Claims

1. A method for preparing nitrogen and phosphorus doped activated carbon, characterized in that: The following steps are involved: Heat-treating a mixture containing a biomass raw material, a pyridine nitrogen source, a pyrrole nitrogen source, and an oxidant solution, and collecting a solid after the heat treatment is completed to obtain a first precursor; the heat treatment is heating at 160 to 200° C. for 8 to 24 hours; Annealing the first precursor in an inert atmosphere to obtain a second precursor; the annealing is performed at 700 to 900° C. for 1 to 3 hours; The second precursor, the activator, the binder and the dispersant are mixed and then extruded to obtain a green body; Carrying out carbonization treatment on the green body in an inert atmosphere to obtain a carbonized body; Activating the carbonized body in an activation gas atmosphere to obtain an activated body; The activated body is immersed in a solution containing a phosphorus-containing precursor, and after the immersion is completed, a solid is collected and dried to obtain a third precursor; The third precursor is calcined in an air atmosphere to obtain nitrogen-phosphorus doped activated carbon; The nitrogen and phosphorus doped activated carbon is used for desulfurization.

2. The method for preparing nitrogen and phosphorus doped activated carbon according to claim 1, characterized in that: The biomass raw material is fresh bamboo dried at 90-110° C. for 6-10 hours; The mixture also contains at least one of PVP, CTAB, SDS, PEG, PAA, sodium citrate, and sodium gluconate; The pyridinic nitrogen source is at least one of melamine, pyridine, aniline and pyrazine; The pyrrolic nitrogen source is at least one of urea, melamine and polypyrrole; The oxidant is any one of potassium permanganate, potassium ferrate and hydrogen peroxide.

3. The method for preparing nitrogen and phosphorus doped activated carbon according to claim 1, characterized in that: The activator is potassium carbonate and / or potassium hydroxide; The adhesive is at least one of starch, cellulose and molasses; The dispersant is water.

4. The method for preparing nitrogen and phosphorus doped activated carbon according to claim 1, characterized in that: The carbonization treatment is carried out at 600-800° C. for 1-3 hours.

5. The method for preparing nitrogen and phosphorus doped activated carbon according to claim 1, characterized in that: The activation treatment is performed at 700-900° C. for 1-3 hours, and the activation gas atmosphere is water vapor.

6. The method for preparing nitrogen and phosphorus doped activated carbon according to claim 1, characterized in that: The phosphorus-containing precursor is any one of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and ammonium hydrogen phosphate.

7. The method for preparing nitrogen and phosphorus doped activated carbon according to claim 6, characterized in that: The calcination treatment is performed at 350-500° C. for 0.5-2 hours.

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