A starch polysaccharide-based organic chlorine and inorganic chlorine co-removal type dechlorination agent and a preparation method thereof

Abstract

An organochlorine and inorganic chlorine co-removal dechlorinating agent based on starch polysaccharide biochar and its preparation method are disclosed, belonging to the field of dechlorination technology. The preparation method of the organochlorine and inorganic chlorine co-removal dechlorinating agent based on starch polysaccharide biochar includes four steps: preparation of phosphorus and nitrogen-coated microcrystalline cellulose, hydrothermal combined carbonization, potassium salt activation, and secondary steam activation. The resulting organochlorine and inorganic chlorine co-removal dechlorinating agent based on starch polysaccharide biochar exhibits an organochlorine removal rate of 98.8-99.6%, an inorganic chlorine penetration capacity of 38.9-41.3%, and a crushing strength of 134-140 N·cm. ‑1 The wear rate is 1.2~1.5%.

Description

Technical Field

[0001] This invention relates to an organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar and its preparation method, belonging to the field of dechlorination technology. Background Technology

[0002] Crude oil and its secondary processing materials from refining and reforming contain chlorides in both inorganic and organic forms. Inorganic chlorides mainly originate from inorganic salts carried by the crude oil itself, while organic chlorides come from organic chloride complexes present in the crude oil and chemical additives added during extraction and refining. Although advanced electro-desalting technology and equipment exist in crude oil pretreatment, desalted crude oil still contains a small amount of inorganic chloride and the vast majority of organic chlorides. These inorganic and organic chlorides can cause corrosion and blockage of refining equipment and pipelines, and can also affect subsequent extraction solvents, thus impacting downstream production. Therefore, it is necessary to remove inorganic and organic chlorides from crude oil and its secondary processing materials from refining and reforming (such as reformate and naphtha). Currently, the most widely used technology for removing inorganic and organic chlorides both domestically and internationally is solid adsorption dechlorination technology, which utilizes solid dechlorinating agents to adsorb organic and inorganic chlorides from liquid oil. This technology is characterized by its simple process and low investment cost.

[0003] While solid adsorption dechlorination technology possesses significant advantages, the core material used in this technology, namely the solid dechlorinating agent, still has many shortcomings that need to be addressed. Due to the low mass transfer rate in the liquid phase system, the application effect of solid dechlorinating agents is relatively poor, especially for crude oil and its secondary processing materials from refining and reforming processes with particularly high organic chlorine content and low inorganic chlorine content. Solid dechlorinating agents rely on both physical and chemical adsorption to remove trace amounts of inorganic chlorine and high levels of organic chlorine from reformed oil. The adsorption process places high demands on the specific surface area, pore size distribution, and operating pressure of the dechlorinating agent. Solid dechlorinating agents used in the liquid phase are generally prepared by kneading or impregnation methods. Their main reactants are active substances capable of adsorbing organic chlorine and oxides of alkali metals, alkaline earth metals, or transition metals capable of reacting with inorganic chlorine (hydrogen chloride). For example, by impregnating oxides of Cu, Mg, Fe, and Mn onto a porous carrier, these oxide active components can adsorb organic chlorine and react with inorganic chlorine simultaneously, thus achieving the simultaneous removal of trace amounts of organic and inorganic chlorine. However, in the liquid phase, the diffusion resistance of organic and inorganic chlorines is very high. Therefore, when removing organic and inorganic chlorines from the liquid phase, the dechlorinating agent must consider not only the active component but also parameters such as the specific surface area, pore size, and pore size distribution of the carrier. These parameters directly affect the dispersion of the active component in the dechlorinating agent, thus affecting the contact efficiency between the active component and the organic and inorganic chlorines in the reformate, ultimately determining the dechlorination effect. Furthermore, the crushing strength and abrasion rate of the dechlorinating agent are also crucial. Too low a crushing strength can easily lead to an increased pressure drop within the dechlorination unit, posing a risk of damage and severely impacting the dechlorination effect. Simultaneously, the pulverization of the dechlorinating agent can easily contaminate the materials within the unit. The abrasion rate mainly relates to the degradation of the dechlorination performance and the service life of the dechlorinating agent. A high abrasion rate leads to frequent replacements of the dechlorinating agent, increasing the operating costs of the dechlorination unit.

[0004] Chinese patent CN120001332A discloses a dechlorinating agent for reformed oil and its preparation method. The dechlorinating agent comprises: an active component, a carrier, and a binder; wherein the active component is sodium carbonate and / or sodium bicarbonate, and the carrier includes alumina powder and alkaline-washed waste FER molecular sieve; the specific surface area of ​​the dechlorinating agent is 60~150 m² / g. 2 / g, with an average pore size of 10.5~18.5nm. The reforming oil dechlorinating agent obtained by this patent can only remove inorganic chlorine and has no effect on removing organic chlorine.

[0005] Chinese patent CN117504807A discloses a macroporous liquid-phase dechlorination agent, its preparation method, and its application. The raw material composition of the macroporous liquid-phase dechlorination agent includes 45-70 parts of dechlorination active substance M modified silica gel micropowder; 15-25 parts of inorganic macroporous material; and 15-25 parts of clay. The dechlorination active substance M is selected from one or more elements of Ca, Mg, and / or Zn, Fe, and Cu. The liquid-phase dechlorination agent prepared by this patent only has the function of removing inorganic chlorine and cannot simultaneously remove organic chlorine.

[0006] As can be seen, solid dechlorinating agents used for dechlorination of crude oil and its secondary processing materials (such as reformed oil and naphtha) have significant drawbacks, such as difficulty in simultaneously removing organic and inorganic chlorines. They also suffer from low chlorine penetration capacity and poor mechanical properties. Therefore, in the field of dechlorination of crude oil and its secondary processing materials, developing a co-dechlorinating agent that combines inorganic chlorine penetration capacity, high organic chlorine removal rate, good mechanical properties, and long-term recyclability is a product development solution with great practical value. Summary of the Invention

[0007] To address the shortcomings of the existing technologies, this invention provides an organochlorine and inorganic chlorine co-removal dechlorinating agent based on starch polysaccharide biochar and its preparation method, achieving the following objectives: to prepare an organochlorine and inorganic chlorine co-removal dechlorinating agent with high organochlorine adsorption capacity and inorganic chlorine penetration capacity, which also has the advantages of high crushing strength and low abrasion rate, and can be used for the simultaneous removal of organochlorine and inorganic chlorine from crude oil and its secondary refining and reforming materials.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: An organochlorine and inorganic chlorine co-removal dechlorinating agent based on starch polysaccharide biochar and its preparation method are disclosed. The organochlorine removal rate of the dechlorinating agent based on starch polysaccharide biochar is 98.8-99.6%, the inorganic chlorine penetration capacity is 38.9-41.3%, and the crushing strength is 134-140 N·cm. -1 The wear rate is 1.2~1.5%; The preparation method of the organochlorine and inorganic chlorine co-dechlorination dechlorinator based on starch polysaccharide biochar includes four steps: preparation of phosphorus and nitrogen coated microcrystalline cellulose, hydrothermal combined carbonization, potassium salt activation, and secondary activation by steam. The following are further improvements to the above technical solution: Step 1: Preparation of phosphorus and nitrogen-coated microcrystalline cellulose Microcrystalline cellulose and deionized water were added to the reaction vessel and quickly stirred to disperse them evenly. Phytic acid was added under low-speed stirring. After heating to the esterification reaction temperature, sulfuric acid aqueous solution was added. After the esterification reaction was complete, melamine resin prepolymer aqueous solution was added. Stirring was continued at a constant temperature until the reaction was complete. The material was then cooled and discharged. After filtration, washing and drying, phosphorus and nitrogen coated microcrystalline cellulose was obtained. The microcrystalline cellulose has a particle size of 1~35μm; The melamine resin prepolymer is one or a mixture of two of hexamethylol melamine and methyl etherified hexamethylol melamine in any mass ratio; The sulfuric acid aqueous solution has a sulfuric acid concentration of 6-15% by mass. The mass concentration of melamine resin prepolymer in the aqueous solution of the melamine resin prepolymer is 10-30%; The mass ratio of the microcrystalline cellulose, deionized water, phytic acid, sulfuric acid aqueous solution, and melamine resin prepolymer aqueous solution is 40~150:100~600:8~50:10~45:25~90; The rapid stirring and dispersion is carried out at a stirring rate of 5000~9500 rpm for 1~5 hours. The low-speed stirring has a stirring rate of 900~2600 rpm; The esterification reaction temperature is 60~95℃; After the esterification reaction is complete, the esterification reaction time is 4-8 hours. The mixture is stirred at a constant temperature until the reaction is complete, and the reaction time is 5-11 hours. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 6.4-7. The drying process involves a drying temperature of 60-85℃ and a drying time of 15-28 hours.

[0009] Step 2, hydrothermal combined carbonization Starch, phosphorus and nitrogen-coated microcrystalline cellulose, and deionized water are added to a dispersion vessel and stirred at a constant temperature until evenly dispersed. The mixture is then transferred to a hydrothermal reactor and subjected to hydrothermal carbonization. After cooling to room temperature, the mixture is discharged, filtered, washed, and dried to obtain the hydrothermal product. After further carbonization, the activated carbon is obtained as a primary product. The mass ratio of starch, phosphorus-nitrogen coated microcrystalline cellulose, and deionized water is 60~200:10~70:200~1200; The constant temperature stirring and dispersion is uniform, with a temperature of 40~75℃, a stirring and dispersion rate of 3000~6500 rpm, and a stirring and dispersion time of 1.5~4h; The hydrothermal carbonization reaction is carried out at a temperature of 180~230℃ for a reaction time of 8~20h. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 6.8 to 7.3. The drying process involves a drying temperature of 80-115℃ and a drying time of 13-24 hours. The carbonization process specifically involves placing the hydrothermal product into a carbonization furnace, heating it to 750-900℃ at a heating rate of 5-9℃ / min under nitrogen protection at a flow rate of 100-200 mL / min, and then carbonizing it at a constant temperature for 0.5-1.5 hours.

[0010] Step 3: Potassium salt activation After mixing the activated carbon raw material, potassium tetraborate powder, and carbon-containing potassium salt powder evenly, the mixture is placed in an activation furnace and fully activated. After cooling to room temperature, the material is discharged to obtain potassium salt activated activated carbon. The carbon-containing potassium salt is selected from one or more of potassium carbonate, potassium oxalate, and potassium citrate, or a mixture of any two or more in any mass ratio. The mass ratio of the activated carbon primary product, potassium tetraborate powder, and carbon-containing potassium salt powder is 180~550:8~30:20~90; The specific operating conditions for full activation are as follows: under nitrogen protection at a flow rate of 150~300mL / min, the temperature is increased to 850~940℃ at a heating rate of 3~10℃ / min, and activated at a constant temperature for 0.8~2h.

[0011] Step 4: Secondary activation with water vapor Potassium salt activated carbon is placed in an aqueous solution of potassium methylsilicate, fully impregnated, and then dried at low temperature. The dried activated carbon is then placed in an activation furnace for secondary activation with steam, and then dried again to obtain an organochlorine and inorganic chlorine co-dechlorination dechlorinating agent based on starch polysaccharide biochar. The potassium methylsilicate aqueous solution has a mass concentration of 15-40 wt%. The specific operation of the full impregnation is as follows: the activated carbon activated by potassium salt is completely immersed in an aqueous solution of potassium methylsilicate, and after standing for 8 to 15 hours, it is filtered to obtain the impregnated activated carbon. The low-temperature drying process involves a drying temperature of 60-85℃ and a drying time of 12-26 hours. The secondary activation with steam is specifically performed as follows: After the activated carbon is placed in the activation furnace, nitrogen gas with a flow rate of 200-500 mL / min is introduced and continuously introduced for 20-30 minutes to completely replace the air in the activation furnace and the activated carbon with nitrogen gas. Under nitrogen protection, the temperature is increased at a rate of 4-10℃ / min and kept constant at 800-900℃. Then, the nitrogen gas is stopped, and water vapor with a flow rate of 0.4-1.5 g / min is introduced. After constant temperature activation for 1-3.5 hours, the water vapor is switched to nitrogen gas, and the nitrogen protection is reduced to room temperature to obtain activated carbon with secondary activation with steam. The subsequent drying process involves placing the activated carbon, which has been activated a second time with steam, into an oven and drying it at 85-100°C for 13-20 hours.

[0012] Compared with the prior art, the present invention achieves the following beneficial effects: 1. This invention utilizes the esterification reaction between phytic acid and the hydroxyl groups on the surface of microcrystalline cellulose, and the surface coating of esterified microcrystalline cellulose with melamine prepolymer, to introduce phosphorus and nitrogen elements into the polysaccharide precursor of activated carbon. The esterification reaction between phytic acid and the hydroxyl groups on the surface of microcrystalline cellulose results in a more uniform distribution of phosphorus on the surface of the polysaccharide precursor. Similarly, the surface coating of esterified microcrystalline cellulose with melamine prepolymer also results in a more uniform distribution of nitrogen on the surface of the polysaccharide precursor. Thus, the activated carbon obtained after blending starch and microcrystalline cellulose containing both phosphorus and nitrogen elements exhibits a very uniform distribution of phosphorus and nitrogen elements. This uniform distribution of phosphorus and nitrogen avoids excessive damage to the microscopic carbon skeleton structure inside the activated carbon caused by the introduction of large-volume phosphorus and nitrogen atoms, and also improves the internal microstructure of the activated carbon. The polarity of the pore walls enhances the adsorption capacity for highly polar organic chlorides and chloride ions. Furthermore, compared to direct one-step carbonization, hydrothermal co-carbonization, at a lower temperature, allows phosphorus and nitrogen to readily undergo a preliminary co-carbonization reaction with carbon. This avoids the drawbacks of one-step carbonization, where phosphorus and nitrogen rapidly decompose and overflow during high-temperature carbonization, resulting in low phosphorus and nitrogen content in the final activated carbon and difficulty in embedding them into the carbon atom microstructure. The wider hydrothermal carbonization reaction temperature range also allows for the regulation of the bonding between phosphorus and nitrogen and the activated carbon atom microstructure, as well as the content of phosphorus and nitrogen. Ultimately, hydrothermal co-carbonization aims to adjust the polarity of the micropore walls and the micropore structure within the activated carbon. 2. This invention uses potassium tetraborate powder and carbon-containing potassium salt powder to replace conventional potassium hydroxide for activating and pore-forming activated carbon. Compared to potassium hydroxide, potassium tetraborate powder and carbon-containing potassium salt powder are much less alkaline, which can reduce the corrosive effect of the strong alkali potassium hydroxide on equipment. However, the activation effect of potassium tetraborate powder or carbon-containing potassium salt powder alone is far inferior to that of potassium hydroxide. This invention achieves an effect comparable to potassium hydroxide activation by optimizing the combination of potassium tetraborate powder and carbon-containing potassium salt powder, and combining it with a secondary steam activation process. Potassium tetraborate and carbon-containing potassium salt powder have a very good synergistic effect in promoting activation efficiency and increasing the number of micropores in activated carbon. This may be because the carbon-containing potassium salt powder reacts with heat... Both potassium carbonate and potassium tetraborate decompose to form potassium carbonate, but potassium carbonate has a higher decomposition temperature and lower activation efficiency on the carbon matrix. Potassium tetraborate, on the other hand, has a relatively lower decomposition temperature, and the boron oxide produced by decomposition is in a molten liquid state, which has good wettability on the internal pores of the carbon matrix. Moreover, liquid boron oxide can dissolve potassium oxide, which promotes the decomposition of potassium carbonate, increases the amount of potassium oxide produced, and thus promotes the rate of potassium vapor production from potassium oxide decomposition. Potassium vapor plays a very important role in etching and expanding the microporous structure of the carbon matrix. Therefore, potassium tetraborate and carbon-containing potassium salt powder show a very good synergistic effect in activation and pore formation, which can significantly increase the number of micropores inside activated carbon, thereby improving the inorganic chlorine penetration capacity and organic chlorine removal rate. 3. In the secondary steam activation process of this invention, the activated carbon activated by potassium salt is impregnated with potassium methylsilicate. Utilizing the strong permeability of potassium methylsilicate, more potassium elements are injected into the micropores of the activated carbon during impregnation. Under the high temperature conditions of steam activation, potassium methylsilicate easily decomposes into a large amount of potassium oxide. This potassium oxide reacts with steam to form potassium hydroxide, which has a strong corrosive and pore-expanding effect on the carbon matrix. Furthermore, in the potassium salt activation process, this invention does not further degrade the activated carbon after potassium salt activation. Washing or acid-washing activated carbon leaves a large amount of potassium in the micropores. Most of this potassium exists in the form of potassium oxide, which reacts with water vapor to form potassium hydroxide, promoting the activation and pore-forming process. In addition, potassium ions are easily adsorbed and deposited on the inner surface of the micropores of activated carbon. Strongly alkaline potassium ions are active substances that increase the removal of inorganic chlorine. Therefore, activated carbon impregnated with potassium methylsilicate and activated by potassium salts is not washed or acid-washed, which can greatly improve the adsorption performance of activated carbon for inorganic chlorine, thereby greatly increasing the inorganic chlorine penetration capacity. 4. The organochlorine and inorganic chlorine co-removal dechlorinator based on starch polysaccharide biochar obtained in this invention has an organochlorine removal rate of 98.8-99.6%. In reformed oil with an inorganic chlorine content of approximately 5 μg / L and a water content of approximately 25 μg / L, the dechlorination was carried out at 80℃, 1 MPa, and a liquid hourly space velocity of 6 h⁻¹. -1Under approximately [condition], the measured inorganic chlorine breakthrough chlorine capacity was 38.9%–41.3%, and the crushing strength was 134–140 N·cm. -1 The wear rate is 1.2~1.5%. Attached Figure Description

[0013] Figure 1 The cross-sectional image of the organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar obtained in Example 1 is magnified 10,000 times. Figure 2 The image shows a scanning electron microscope (SEM) image of the cross-section of the organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar obtained in Example 1, magnified 50,000 times. Detailed Implementation

[0014] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0015] Example 1: A method for preparing an organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar Step 1: Preparation of phosphorus and nitrogen-coated microcrystalline cellulose Microcrystalline cellulose and deionized water were added to the reaction vessel and quickly stirred to disperse them evenly. Phytic acid was added under low-speed stirring. After heating to the esterification reaction temperature, sulfuric acid aqueous solution was added. After the esterification reaction was complete, melamine resin prepolymer aqueous solution was added. Stirring was continued at a constant temperature until the reaction was complete. The material was then cooled and discharged. After filtration, washing and drying, phosphorus and nitrogen coated microcrystalline cellulose was obtained. The microcrystalline cellulose has a particle size of 20 μm; The melamine resin prepolymer is hexamethylol melamine; The sulfuric acid in the aqueous solution has a sulfuric acid concentration of 11% by mass. The mass concentration of melamine resin prepolymer in the aqueous solution of the melamine resin prepolymer is 20%. The mass ratio of the microcrystalline cellulose, deionized water, phytic acid, sulfuric acid aqueous solution, and melamine resin prepolymer aqueous solution is 100:400:24:30:65. The rapid stirring and dispersion process involves a stirring rate of 7500 rpm and a stirring and dispersion time of 4 hours. The low-speed stirring has a stirring rate of 1600 rpm; The esterification reaction temperature is 85°C; After the esterification reaction is complete, the esterification reaction time is 7 hours. The mixture is stirred at a constant temperature until the reaction is complete, and the reaction time is 9 hours. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 6.8. The drying process was carried out at a temperature of 75°C for 22 hours.

[0016] Step 2, hydrothermal combined carbonization Starch, phosphorus and nitrogen-coated microcrystalline cellulose, and deionized water are added to a dispersion vessel and stirred at a constant temperature until evenly dispersed. The mixture is then transferred to a hydrothermal reactor and subjected to hydrothermal carbonization. After cooling to room temperature, the mixture is discharged, filtered, washed, and dried to obtain the hydrothermal product. After further carbonization, the activated carbon is obtained as a primary product. The mass ratio of starch, phosphorus-nitrogen coated microcrystalline cellulose, and deionized water is 130:40:800; The constant temperature stirring and dispersion is uniform, with a temperature of 65℃, a stirring and dispersion rate of 4500 rpm, and a stirring and dispersion time of 3 hours; The hydrothermal carbonization reaction is carried out at a temperature of 200°C for a reaction time of 15 hours. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 7.1. The drying process is carried out at a temperature of 100°C for 18 hours. The carbonization process specifically involves placing the hydrothermal product into a carbonization furnace, heating it to 800°C at a rate of 7°C / min under nitrogen protection at a flow rate of 160 mL / min, and then carbonizing it at this constant temperature for 1 hour.

[0017] Step 3: Potassium salt activation After mixing the activated carbon raw material, potassium tetraborate powder, and carbon-containing potassium salt powder evenly, the mixture is placed in an activation furnace and fully activated. After cooling to room temperature, the material is discharged to obtain potassium salt activated activated carbon. The carbon-containing potassium salt is potassium carbonate; The mass ratio of the activated carbon primary product, potassium tetraborate powder, and carbon-containing potassium salt powder is 350:20:73. The specific operating conditions for full activation are as follows: under nitrogen protection at a flow rate of 220 mL / min, the temperature is increased to 900℃ at a heating rate of 5℃ / min, and activated at a constant temperature for 1 hour.

[0018] Step 4: Secondary activation with water vapor Potassium salt activated carbon is placed in an aqueous solution of potassium methylsilicate, fully impregnated, and then dried at low temperature. The dried activated carbon is then placed in an activation furnace for secondary activation with steam, and then dried again to obtain an organochlorine and inorganic chlorine co-dechlorination dechlorinating agent based on starch polysaccharide biochar. The potassium methylsilicate aqueous solution has a mass concentration of 25 wt%. The specific operation of the full impregnation is as follows: the activated carbon activated by potassium salt is completely immersed in an aqueous solution of potassium methylsilicate, and after standing for 11 hours, the impregnated activated carbon is obtained by filtration. The low-temperature drying process involves a drying temperature of 80°C and a drying time of 16 hours. The secondary activation with steam is specifically performed as follows: After the activated carbon is placed in the activation furnace, nitrogen gas with a flow rate of 300 mL / min is introduced and continuously introduced for 26 minutes to completely replace the air in the activation furnace and the activated carbon with nitrogen gas. Under nitrogen protection, the temperature is raised at a rate of 8℃ / min and kept constant at 860℃. Then, the nitrogen gas is stopped, and water vapor with a flow rate of 1 g / min is introduced. After constant temperature activation for 2 hours, the water vapor is switched to nitrogen gas, and the nitrogen protection is lowered to room temperature to obtain activated carbon with secondary activation with steam. The subsequent drying process involves placing the activated carbon, which has been reactivated by steam, into an oven and drying it at 90°C for 18 hours.

[0019] Example 2: A method for preparing an organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar Step 1: Preparation of phosphorus and nitrogen-coated microcrystalline cellulose Microcrystalline cellulose and deionized water were added to the reaction vessel and quickly stirred to disperse them evenly. Phytic acid was added under low-speed stirring. After heating to the esterification reaction temperature, sulfuric acid aqueous solution was added. After the esterification reaction was complete, melamine resin prepolymer aqueous solution was added. Stirring was continued at a constant temperature until the reaction was complete. The material was then cooled and discharged. After filtration, washing and drying, phosphorus and nitrogen coated microcrystalline cellulose was obtained. The microcrystalline cellulose has a particle size of 1 μm; The melamine resin prepolymer is methyl etherified hexamethyl hydroxymethyl melamine; The sulfuric acid in the sulfuric acid aqueous solution has a mass concentration of 6%. The mass concentration of melamine resin prepolymer in the aqueous solution of the melamine resin prepolymer is 10%. The mass ratio of the microcrystalline cellulose, deionized water, phytic acid, sulfuric acid aqueous solution, and melamine resin prepolymer aqueous solution is 40:100:8:10:25. The rapid stirring and dispersion is carried out at a stirring rate of 5000 rpm for 1 hour. The low-speed stirring has a stirring rate of 900 rpm; The esterification reaction temperature is 60°C; After the esterification reaction is complete, the esterification reaction time is 4 hours. The mixture is stirred at a constant temperature until the reaction is complete, and the reaction time is 5 hours. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 6.4. The drying process is carried out at a temperature of 60°C for 28 hours.

[0020] Step 2, hydrothermal combined carbonization Starch, phosphorus and nitrogen-coated microcrystalline cellulose, and deionized water are added to a dispersion vessel and stirred at a constant temperature until evenly dispersed. The mixture is then transferred to a hydrothermal reactor and subjected to hydrothermal carbonization. After cooling to room temperature, the mixture is discharged, filtered, washed, and dried to obtain the hydrothermal product. After further carbonization, the activated carbon is obtained as a primary product. The mass ratio of starch, phosphorus-nitrogen coated microcrystalline cellulose, and deionized water is 60:10:200. The constant temperature stirring and dispersion is uniform, with a temperature of 40℃, a stirring and dispersion rate of 3000 rpm, and a stirring and dispersion time of 1.5 h; The hydrothermal carbonization reaction is carried out at a temperature of 180°C for 8 hours. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 6.8. The drying process is carried out at a temperature of 80°C for 24 hours. The carbonization process specifically involves placing the hydrothermal product into a carbonization furnace, heating it to 750°C at a rate of 5°C / min under nitrogen protection at a flow rate of 100 mL / min, and then carbonizing it at this constant temperature for 1.5 hours.

[0021] Step 3: Potassium salt activation After mixing the activated carbon raw material, potassium tetraborate powder, and carbon-containing potassium salt powder evenly, the mixture is placed in an activation furnace and fully activated. After cooling to room temperature, the material is discharged to obtain potassium salt activated activated carbon. The carbon-containing potassium salt is potassium oxalate; The mass ratio of the activated carbon primary product, potassium tetraborate powder, and carbon-containing potassium salt powder is 180:8:20. The specific operating conditions for full activation are as follows: under nitrogen protection at a flow rate of 150 mL / min, the temperature is increased to 850°C at a heating rate of 3°C / min, and activated at a constant temperature for 2 hours.

[0022] Step 4: Secondary activation with water vapor Potassium salt activated carbon is placed in an aqueous solution of potassium methylsilicate, fully impregnated, and then dried at low temperature. The dried activated carbon is then placed in an activation furnace for secondary activation with steam, and then dried again to obtain an organochlorine and inorganic chlorine co-dechlorination dechlorinating agent based on starch polysaccharide biochar. The potassium methylsilicate aqueous solution has a mass concentration of 15 wt%. The specific operation of the full impregnation is as follows: the activated carbon activated by potassium salt is completely immersed in an aqueous solution of potassium methylsilicate, and after standing for 8 hours, the impregnated activated carbon is obtained by filtration. The low-temperature drying process involves a drying temperature of 60°C and a drying time of 26 hours. The secondary activation with steam is specifically performed as follows: After the activated carbon is placed in the activation furnace, nitrogen gas with a flow rate of 200 mL / min is introduced and continuously introduced for 30 minutes to completely replace the air in the activation furnace and the activated carbon with nitrogen gas. Under nitrogen protection, the temperature is increased at a rate of 4℃ / min and kept constant at 900℃. Then, the nitrogen gas is stopped, and water vapor with a flow rate of 0.4 g / min is introduced. After constant temperature activation for 3.5 hours, the water vapor is switched to nitrogen gas, and the nitrogen protection is reduced to room temperature to obtain activated carbon with secondary activation with steam. The subsequent drying process involves placing the activated carbon, which has been reactivated by steam, into an oven and drying it at 85°C for 20 hours.

[0023] Example 3: A method for preparing an organochlorine-inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar Step 1: Preparation of phosphorus and nitrogen-coated microcrystalline cellulose Microcrystalline cellulose and deionized water were added to the reaction vessel and quickly stirred to disperse them evenly. Phytic acid was added under low-speed stirring. After heating to the esterification reaction temperature, sulfuric acid aqueous solution was added. After the esterification reaction was complete, melamine resin prepolymer aqueous solution was added. Stirring was continued at a constant temperature until the reaction was complete. The material was then cooled and discharged. After filtration, washing and drying, phosphorus and nitrogen coated microcrystalline cellulose was obtained. The microcrystalline cellulose has a particle size of 35 μm; The melamine resin prepolymer is hexamethylol melamine; The sulfuric acid in the aqueous solution has a sulfuric acid concentration of 15% by mass. The mass concentration of melamine resin prepolymer in the aqueous solution of the melamine resin prepolymer is 30%. The mass ratio of the microcrystalline cellulose, deionized water, phytic acid, sulfuric acid aqueous solution, and melamine resin prepolymer aqueous solution is 150:600:50:45:90. The rapid stirring and dispersion process involves a stirring rate of 9500 rpm and a stirring and dispersion time of 5 hours. The low-speed stirring has a stirring rate of 2600 rpm; The esterification reaction temperature is 95°C; After the esterification reaction is complete, the esterification reaction time is 8 hours. The mixture was stirred at a constant temperature until the reaction was complete, and the reaction time was 11 hours. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 7. The drying process is carried out at a temperature of 85°C for 15 hours.

[0024] Step 2, hydrothermal combined carbonization Starch, phosphorus and nitrogen-coated microcrystalline cellulose, and deionized water are added to a dispersion vessel and stirred at a constant temperature until evenly dispersed. The mixture is then transferred to a hydrothermal reactor and subjected to hydrothermal carbonization. After cooling to room temperature, the mixture is discharged, filtered, washed, and dried to obtain the hydrothermal product. After further carbonization, the activated carbon is obtained as a primary product. The mass ratio of starch, phosphorus-nitrogen coated microcrystalline cellulose, and deionized water is 200:70:1200; The constant temperature stirring and dispersion is uniform, the temperature is 75℃, the stirring and dispersion rate is 6500 rpm, and the stirring and dispersion time is 4 hours; The hydrothermal carbonization reaction is carried out at a temperature of 230°C for a reaction time of 20 hours. The washing process involves washing the filtrate with deionized water until the pH of the washing solution reaches 7.3. The drying process was carried out at a temperature of 115°C for 13 hours. The carbonization process specifically involves placing the hydrothermal product into a carbonization furnace, heating it to 900°C at a rate of 9°C / min under nitrogen protection at a flow rate of 200 mL / min, and then carbonizing it at a constant temperature for 0.5 h.

[0025] Step 3: Potassium salt activation After mixing the activated carbon raw material, potassium tetraborate powder, and carbon-containing potassium salt powder evenly, the mixture is placed in an activation furnace and fully activated. After cooling to room temperature, the material is discharged to obtain potassium salt activated activated carbon. The carbon-containing potassium salt is potassium citrate; The mass ratio of the activated carbon primary product, potassium tetraborate powder, and carbon-containing potassium salt powder is 550:30:90. The specific operating conditions for full activation are as follows: under nitrogen protection at a flow rate of 300 mL / min, the temperature is increased to 940°C at a heating rate of 10°C / min, and then activated at a constant temperature for 0.8 h.

[0026] Step 4: Secondary activation with water vapor Potassium salt activated carbon is placed in an aqueous solution of potassium methylsilicate, fully impregnated, and then dried at low temperature. The dried activated carbon is then placed in an activation furnace for secondary activation with steam, and then dried again to obtain an organochlorine and inorganic chlorine co-dechlorination dechlorinating agent based on starch polysaccharide biochar. The potassium methylsilicate aqueous solution has a mass concentration of 40 wt%. The specific operation of the full impregnation is as follows: the activated carbon activated by potassium salt is completely immersed in an aqueous solution of potassium methylsilicate, and after standing for 15 hours, the impregnated activated carbon is obtained by filtration. The low-temperature drying process involves a drying temperature of 85°C and a drying time of 12 hours. The secondary activation with steam is specifically performed as follows: After the activated carbon is placed in the activation furnace, nitrogen gas with a flow rate of 500 mL / min is introduced and continuously introduced for 20 minutes to completely replace the air in the activation furnace and the activated carbon with nitrogen gas. Under nitrogen protection, the temperature is raised at a rate of 10℃ / min and kept constant at 800℃. Then, the nitrogen gas is stopped, and water vapor with a flow rate of 1.5 g / min is introduced. After constant temperature activation for 1 hour, the water vapor is switched to nitrogen gas, and the nitrogen protection is lowered to room temperature to obtain activated carbon with secondary activation with steam. The subsequent drying process involves placing the activated carbon, which has been reactivated by steam, into an oven and drying it at 100°C for 13 hours.

[0027] Comparative Example 1: Based on Example 1, step 1, preparation of phosphorus and nitrogen-coated microcrystalline cellulose, was omitted. In step 2, hydrothermal co-carbonization, 40 parts of phosphorus and nitrogen-coated microcrystalline cellulose were replaced with an equal amount of 40 parts of microcrystalline cellulose. The specific operation is as follows: Step 1, preparing phosphorus and nitrogen-coated microcrystalline cellulose, is omitted; Step 2, hydrothermal combined carbonization Based on Example 1, 40 parts of phosphorus and nitrogen coated microcrystalline cellulose were replaced with an equal amount of microcrystalline cellulose, and other operations were the same as in Example 1; The microcrystalline cellulose has a particle size of 20 μm; Steps 3 and 4 are the same as in Example 1.

[0028] Comparative Example 2: Based on Example 1, in step 3, potassium salt activation, 20 parts of potassium tetraborate powder were replaced with 20 parts of carbon-containing potassium salt powder. The specific operation is as follows: Steps 1 and 2 are the same as in Example 1; Step 3: Potassium salt activation Replace 20 parts of potassium tetraborate powder with 20 parts of carbon-containing potassium salt powder, and perform the other operations as in Example 1; The carbon-containing potassium salt is potassium carbonate; Step 4 is the same as in Example 1.

[0029] Comparative Example 3: Based on Example 1, in step 3, potassium salt activation, 73 parts of carbon-containing potassium salt powder were replaced with 73 parts of potassium tetraborate powder in equal amounts. The specific operation is as follows: Steps 1 and 2 are the same as in Example 1; Step 3: Potassium salt activation Replace 73 parts of carbon-containing potassium salt powder with 73 parts of potassium tetraborate powder, and perform the same operations as in Example 1. Step 4 is the same as in Example 1.

[0030] Comparative Example 4: Based on Example 1, without step 4 (secondary activation with steam), and after step 3 (potassium salt activation), an organochlorine-inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar was directly obtained. The specific operation is as follows: Steps 1 and 2 are the same as in Example 1; Step 3: Potassium salt activation After mixing the activated carbon raw material, potassium tetraborate powder, and carbon-containing potassium salt powder evenly, the mixture is placed in an activation furnace and fully activated. After being cooled to room temperature, the material is discharged to obtain an organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar. Other operations are the same as in Example 1. Step 4, secondary activation with water vapor, is not performed.

[0031] Comparative Example 5: Based on Example 1, in step 4, the secondary activation with steam, the activated carbon activated with potassium salt is not impregnated with an aqueous solution of potassium methylsilicate. The specific operation is as follows: Steps 1, 2, and 3 are the same as in Example 1; Step 4: Secondary activation with water vapor The activated carbon activated by potassium salt was dried at low temperature, and then the dried activated carbon was placed in an activation furnace for secondary activation with steam. After drying, an organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar was obtained. Other operations were the same as in Example 1.

[0032] Performance testing: The following indicators were tested on the organochlorine and inorganic chlorine co-dechlorination agents based on starch polysaccharide biochar obtained in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4, 5: 1. Inorganic chlorine breakthrough chlorine capacity, the test method is as follows: reformed oil with an inorganic chlorine content of approximately 5 μg / L and a water content of approximately 30 μg / L is subjected to chlorination at 80℃, 1 MPa, and a liquid hourly space velocity of 6 h⁻¹. -1 Under certain conditions, a liquid-phase dynamic dechlorination experiment was conducted by loading the dechlorinating agent and measuring the chlorine content in the reformate flowing out of the dechlorination tank. When the chlorine content of the effluent is greater than 0.5 μg / L, it can be considered as breakthrough. The breakthrough chlorine capacity of the dechlorinating agent is obtained by the formula: Breakthrough chlorine capacity = (mass content of chlorine in the dechlorinating agent after breakthrough) / (total mass of the dechlorinating agent after breakthrough) × 100%. 2. Organochlorine removal efficiency: The test method is as follows: Dichloromethane, trichloromethane, carbon tetrachloride, and 1,2-dichloroethane are added to reformed oil with zero organic and inorganic chlorine content. The volume ratio of the four chlorides is 1:1:1:1. After mixing evenly, reformed oil containing organic chlorine is obtained. The content of organic chloride is measured. A certain mass of reformed oil containing organic chlorine is weighed and added to a 250mL round-bottom flask. Then, it is placed in a constant temperature water bath and kept at 80℃. Dechlorinating agent and reformed oil containing organic chlorine are added to the reformed oil containing organic chlorine at a volume ratio of 1:1. Adsorption is carried out at a stirring speed of 200 rpm for 3 hours. After settling, the supernatant is taken and the content of organic chloride in the reformed oil after adsorption is measured to obtain the organic chlorine removal rate of the dechlorinating agent. 3. Crushing strength: The crushing strength shall be tested in accordance with the "HG / T 2782-2024 Determination of Crushing Resistance of Chemical Catalyst Particles"; 4. Wear rate: The wear rate is tested in accordance with "HG / T 2976-2011 Determination of Wear Rate of Fertilizer Catalysts"; The specific test results are shown in Table 1: Table 1 As shown in Table 1, the inorganic chlorine penetration capacity of Examples 1-3 is above 38.9%, the organic chlorine removal rate is above 98.8%, and the crushing strength is above 134 N·cm. -1 The above shows that the abrasion rate is less than 1.2%, indicating that the organochlorine and inorganic chlorine co-removal dechlorinator based on starch polysaccharide biochar obtained in this invention has a very high inorganic chlorine penetration capacity and a very good organic chlorine adsorption capacity. Furthermore, it exhibits high crushing strength and low abrasion rate in terms of mechanical properties. This demonstrates that the organochlorine and inorganic chlorine co-removal dechlorinator prepared in this invention not only possesses excellent inorganic and organic chlorine co-removal performance but also excellent mechanical properties, resulting in good durability and the ability to be recycled multiple times after regeneration. In Comparative Example 1, without step 1 (preparing phosphorus and nitrogen-coated microcrystalline cellulose), the inorganic chlorine penetration capacity of Comparative Example 1 decreased drastically to 22.8%, the organic chlorine removal rate also decreased significantly to 70.4%, and the crushing strength increased significantly to 158 N·cm. -1The wear rate decreased to 0.5%, indicating that the addition of phosphorus and nitrogen to the activated carbon precursor plays a crucial and positive role in improving the adsorption capacity of activated carbon for inorganic and organic chlorines. However, it does damage the mechanical properties of the activated carbon. This may be because phosphorus and nitrogen can be embedded into the original structure of the carbon matrix during the carbonization process of the activated carbon precursor, thereby changing the electron cloud distribution in the original structure. Moreover, nitrogen and phosphorus have stronger electronegativity, which greatly enhances the polarity of the activated carbon, thus significantly improving its adsorption capacity for highly polar chloride ions and chlorinated organic compounds. Macroscopically, this manifests as an increase in the chlorine penetration capacity of inorganic chlorine and an increase in the adsorption efficiency of organic chlorine. Furthermore, the doping of phosphorus and nitrogen elements impairs the mechanical properties of activated carbon. This is mainly because the volume of phosphorus and nitrogen atoms is significantly larger than that of carbon atoms, especially phosphorus atoms, which are much larger than carbon atoms. This makes it very easy to cause dislocation defects between carbon atoms, thus reducing the ordered and regular arrangement of the carbon matrix lattice network inside the activated carbon, which macroscopically manifests as a decrease in mechanical properties. However, compared with Comparative Example 1, the decrease in mechanical properties in the three embodiments of this invention is not serious and is fully capable of meeting the requirements for dechlorination. In Comparative Examples 2 and 3, in step 3, potassium salt activation, Comparative Example 2 only added carbon-containing potassium salt powder, and Comparative Example 3 only added potassium tetraborate powder, which is similar to Example 1. Compared to Example 1, Comparative Examples 2 and 3 showed significant decreases in both inorganic chlorine penetration capacity and organic chlorine removal rate. Comparative Example 2, which only added carbon-containing potassium salt powder, exhibited a greater decrease in both inorganic chlorine penetration capacity and organic chlorine removal rate. Furthermore, the mechanical properties of Comparative Examples 2 and 3 were slightly higher than those of Example 1. This indicates that potassium tetraborate and carbon-containing potassium salt powder have a very good synergistic effect in promoting activation efficiency and increasing the number of micropores in activated carbon. This may be because the carbon-containing potassium salt powder decomposes upon heating to produce potassium carbonate, but potassium carbonate has a high decomposition temperature and relatively low activation efficiency on the carbon matrix. In contrast, potassium tetraborate has a relatively lower decomposition temperature, and the resulting boron oxide is in a molten liquid state. The liquid boron oxide has good wettability to the internal pores of the carbon matrix, and it can dissolve potassium oxide, which promotes the decomposition of potassium carbonate, increases the amount of potassium oxide generated, and thus promotes the rate of potassium vapor production from potassium oxide decomposition. Potassium vapor plays a very important role in etching and expanding the microporous structure of the carbon matrix. Therefore, potassium tetraborate and carbon-containing potassium salt powder have a very good synergistic effect in activating and creating pores, which can significantly increase the number of micropores inside the activated carbon, thereby improving the inorganic chlorine penetration capacity and organic chlorine removal rate. Of course, the increase in the number of micropores will have a certain impact on mechanical properties. Macroscopically, it can be seen that the mechanical properties of Example 1 are slightly worse than those of Comparative Example 2 and Comparative Example 3.In Comparative Example 4, without step 4 and secondary activation with steam, both the inorganic chlorine penetration capacity and the organic chlorine removal rate were significantly reduced, but the mechanical properties were significantly increased. This indicates that secondary activation with steam has a very significant pore-expanding effect, further promoting the formation of micropores and the expansion of existing pores, thereby improving the adsorption capacity of inorganic and organic chlorine. In addition, secondary activation with steam may more easily form oxygen-containing polar groups on the inner surface of the micropores of activated carbon, which will increase the polarity of activated carbon and enhance its adsorption of inorganic and organic chlorine. In Comparative Example 5, where potassium salt activated activated carbon was not impregnated with potassium methylsilicate aqueous solution in step 4 and secondary activation with steam, both the inorganic chlorine penetration capacity and the organic chlorine removal rate were significantly reduced. The reduction in inorganic chlorine penetration capacity was particularly large, indicating that impregnation with potassium methylsilicate aqueous solution played a very significant role in pore expansion during secondary activation, simultaneously affecting the activated carbon's adsorption capacity. The inorganic chlorine penetration capacity and organic chlorine removal rate of activated carbon were compared, and the effect of impregnation with potassium methylsilicate aqueous solution on the adsorption of inorganic chlorine was more significant. This may be due to the strong permeability of potassium methylsilicate, which allows more potassium to penetrate into the micropores of the activated carbon after potassium salt activation. Under the high temperature conditions of steam activation, potassium methylsilicate easily decomposes into a large amount of potassium oxide. In step 3, the potassium salt activation process also leaves a large amount of potassium in the micropores of the activated carbon. Most of this potassium exists in the form of potassium oxide in the micropores of activated carbon. This potassium oxide, together with the potassium oxide generated from the decomposition of potassium methylsilicate, reacts with water vapor to form potassium hydroxide. Potassium hydroxide has a strong corrosive and pore-expanding effect on the carbon matrix. In addition, potassium ions are easily adsorbed and deposited on the inner surface of the micropores of activated carbon. Strongly alkaline potassium ions are active substances that increase the removal of inorganic chlorine. Therefore, Comparative Example 5 shows a significant reduction in the inorganic chlorine penetration capacity.

[0033] Appendix Figure 1 and attached Figure 2 The images shown are scanning electron microscope (SEM) images at 10,000x and 50,000x magnification of the cross-section of the organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar obtained in Example 1. Figure 1 Some submicron to micron-sized pores can be observed. These larger pores are likely formed mainly during the activation of potassium tetraborate powder and carbon-containing potassium salt powder at 800℃, and further expanded during the secondary activation process with water vapor. Figure 2Numerous submicron to nanometer-sized micropores can be observed. These micropores are likely due to the incorporation of nitrogen and phosphorus, which creates numerous easily activated defects in the carbon atom framework network. These micropores can form under high temperatures of 800℃ and during secondary activation by steam. This combination of relatively large pore size and microporous microstructure effectively reduces the resistance to the permeation of crude oil and its secondary processing materials through the dechlorinating agent. Simultaneously, the micropores provide a large adsorption surface area, significantly improving the penetration capacity of inorganic chlorine and the removal efficiency of organic chlorine.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an organochlorine-inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar, characterized in that: The preparation method of the organochlorine and inorganic chlorine co-dechlorination dechlorinator based on starch polysaccharide biochar includes four steps: preparation of phosphorus and nitrogen coated microcrystalline cellulose, hydrothermal combined carbonization, potassium salt activation, and secondary activation by steam. To prepare phosphorus and nitrogen-coated microcrystalline cellulose, microcrystalline cellulose and deionized water are added to a reaction vessel, and after rapid stirring and uniform dispersion, phytic acid is added under low-speed stirring. After heating to the esterification reaction temperature, sulfuric acid aqueous solution is added. After the esterification reaction is complete, melamine resin prepolymer aqueous solution is added, and stirring is continued at a constant temperature until the reaction is complete. The material is then cooled and discharged, and after filtration, washing, and drying, phosphorus and nitrogen-coated microcrystalline cellulose is obtained. The hydrothermal combined carbonization process involves adding starch, phosphorus and nitrogen-coated microcrystalline cellulose, and deionized water to a dispersion vessel, stirring and dispersing them evenly at a constant temperature, then transferring them to a hydrothermal reactor. After hydrothermal carbonization, the mixture is cooled to room temperature and discharged. After filtration, washing, and drying, the hydrothermal product is obtained, and after further carbonization, the initial activated carbon product is obtained. The potassium salt activation involves mixing the activated carbon raw material, potassium tetraborate powder, and carbon-containing potassium salt powder evenly, placing them in an activation furnace, activating them fully, and then discharging them at room temperature to obtain potassium salt activated activated carbon. The secondary activation with steam involves immersing the potassium-activated activated carbon in an aqueous solution of potassium methylsilicate, drying it at low temperature, and then placing the dried activated carbon in an activation furnace for secondary activation with steam. After drying, an organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar is obtained.

2. The preparation method of the organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar according to claim 1, characterized in that: The microcrystalline cellulose has a particle size of 1~35μm; The melamine resin prepolymer is one or a mixture of two of hexamethylol melamine and methyl etherified hexamethylol melamine in any mass ratio; The sulfuric acid aqueous solution has a sulfuric acid concentration of 6-15% by mass. The mass concentration of melamine resin prepolymer in the aqueous solution of the melamine resin prepolymer is 10-30%; The mass ratio of the microcrystalline cellulose, deionized water, phytic acid, sulfuric acid aqueous solution, and melamine resin prepolymer aqueous solution is 40~150:100~600:8~50:10~45:25~90.

3. The preparation method of the organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar according to claim 1, characterized in that: The mass ratio of starch, phosphorus-nitrogen coated microcrystalline cellulose, and deionized water is 60~200:10~70:200~1200.

4. The preparation method of the organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar according to claim 1, characterized in that: The carbon-containing potassium salt is selected from one or more of potassium carbonate, potassium oxalate, and potassium citrate, or a mixture of any two or more in any mass ratio. The mass ratio of the activated carbon primary product, potassium tetraborate powder, and carbon-containing potassium salt powder is 180~550:8~30:20~90; The specific operating conditions for full activation are as follows: under nitrogen protection at a flow rate of 150~300mL / min, the temperature is increased to 850~940℃ at a heating rate of 3~10℃ / min, and activated at a constant temperature for 0.8~2h.

5. The preparation method of the organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar according to claim 1, characterized in that: The potassium methylsilicate aqueous solution has a mass concentration of 15-40 wt%. The specific operation of the full impregnation is as follows: the activated carbon activated by potassium salt is completely immersed in an aqueous solution of potassium methylsilicate, and after standing for 8 to 15 hours, it is filtered to obtain the impregnated activated carbon. The low-temperature drying process involves a drying temperature of 60-85℃ and a drying time of 12-26 hours. The secondary activation with steam is specifically performed as follows: After the activated carbon is placed in the activation furnace, nitrogen gas with a flow rate of 200-500 mL / min is introduced and continuously introduced for 20-30 minutes to completely replace the air in the activation furnace and the activated carbon with nitrogen gas. Under nitrogen protection, the temperature is increased at a rate of 4-10℃ / min and kept constant at 800-900℃. Then, the nitrogen gas is stopped, and water vapor with a flow rate of 0.4-1.5 g / min is introduced. After constant temperature activation for 1-3.5 hours, the water vapor is switched to nitrogen gas, and the nitrogen protection is reduced to room temperature to obtain activated carbon with secondary activation by steam.

6. The organochlorine and inorganic chlorine co-dechlorination agent based on starch polysaccharide biochar obtained by any one of the preparation methods according to claims 1-5, characterized in that: The aforementioned dechlorinating agent based on starch polysaccharide biochar, which co-dechlorinates both organic and inorganic chlorines, exhibits an organic chlorine removal rate of 98.8–99.6%, an inorganic chlorine penetration capacity of 38.9–41.3%, and a crushing strength of 134–140 N·cm. -1 The wear rate is 1.2~1.5%.

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