A method for producing porous carbon from waste paper using phosphoric acid

Abstract

A method for generating porous carbon from waste paper using phosphoric acid treatment includes the following steps: first, pretreating the waste paper by mixing it with a sodium hydroxide solution; then, mixing and kneading the pretreated waste paper with a phosphoric acid solution of a specific concentration at a certain impregnation ratio; followed by drying and carbonization under a nitrogen atmosphere with programmed temperature increase; the carbonized product is washed with water until neutral and dried, then activated by passing steam through it at a specific temperature; the activated product is then washed with dilute hydrochloric acid, washed with water until neutral, and finally dried to obtain a porous carbon material with high specific surface area and hierarchical pore structure. This invention uses waste paper as raw material, which is low-cost and realizes the high-value utilization of solid waste; the phosphoric acid activation process is mild, environmentally friendly, and has little corrosion to equipment; the prepared porous carbon has high purity and well-developed pore structure, and has broad application prospects in energy storage and adsorption separation.

Description

Technical Field

[0001] This invention belongs to the field of porous carbon technology, specifically relating to a method for generating porous carbon by treating waste paper with phosphoric acid. Background Technology

[0002] Porous carbon materials, with their high specific surface area, tunable pore structure, excellent electrical conductivity and stable chemical properties, have shown great application potential in fields such as supercapacitors, adsorption separation, water treatment, catalyst supports and energy storage.

[0003] Currently, the preparation of traditional porous carbon materials mainly relies on precursors such as coal, petroleum coke, polymers, or specific biomass (e.g., coconut shells). These raw materials are either non-renewable resources with high costs, or require complex pretreatment processes, increasing the complexity and economic burden of the production process. For activation methods, strong alkaline activators such as potassium hydroxide (KOH) are commonly used. While this method can produce porous carbon with high specific surface area, its strong corrosiveness places demanding requirements on production equipment, consumes a lot of energy, and results in relatively low carbon yield. In addition, zinc chloride (ZnCl2) activation has also been widely used, but this method easily leads to heavy metal residues, potentially causing environmental pollution problems and limiting its application in high-end fields, especially those involving human health.

[0004] Therefore, the demand for low-cost, environmentally friendly carbon material preparation technologies is becoming increasingly urgent. Waste paper, as a massive form of household solid waste, is mainly composed of natural cellulose, which is widely available and extremely inexpensive. Its inherent three-dimensional network fiber structure provides an excellent initial template for constructing porous carbon, potentially simplifying or even eliminating complex molding and pretreatment steps, making it one of the ideal precursors for realizing the high-value utilization of solid waste resources.

[0005] Therefore, developing a technology to prepare porous carbon with excellent performance using waste paper as raw material and employing an environmentally friendly and mild activation method not only has significant economic benefits but also aligns with the development requirements of a green circular economy. Phosphoric acid (H3PO4), as a moderately strong activator, has a relatively mild activation process with low equipment corrosivity. Furthermore, the introduction of phosphorus may functionalize the surface of carbon materials, helping to improve their specific application performance. This invention aims to utilize phosphoric acid to activate waste paper to prepare porous carbon materials, overcoming some of the shortcomings of existing technologies. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for generating porous carbon by treating waste paper with phosphoric acid, which has the characteristics of low cost, high yield and adjustable pore structure.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a method for generating porous carbon by treating waste paper with phosphoric acid, comprising the following steps:

[0008] Step S1: Mix waste paper with sodium hydroxide solution;

[0009] Step S2: Mix the material obtained in step S1 with the phosphoric acid solution according to the impregnation ratio, and knead to obtain waste paper uniformly mixed with phosphoric acid solution.

[0010] Step S3: Dry the mixture obtained in step S2 for 48 hours;

[0011] Step S4: Under a nitrogen atmosphere, the material obtained in step S3 is heated and held at that temperature to undergo carbonization.

[0012] Step S5: Wash the material obtained in step S4 with deionized water until pH=6-8;

[0013] Step S6: Dry the material obtained in step S5 for 48 hours;

[0014] Step S7: Activate the material obtained in step S6 by introducing steam at 800℃, wherein the heating rate is 5℃ / min, the steam introduction rate is 0.5L / min, and the holding time is 1-3h.

[0015] Step S8: Wash the material obtained in step S7 with hydrochloric acid, and then rinse with deionized water until pH=6-8.

[0016] Step 9: Dry the material obtained in step S8 to obtain porous carbon.

[0017] In step S1, the NaOH solution has a mass fraction of 75%.

[0018] In step S2, the impregnation ratio is 2:1; the mass fraction of the phosphoric acid solution is 20%.

[0019] In step S3, the drying temperature is 80°C.

[0020] In step S4, the carbonization temperature is 800℃, the heating rate is 5℃ / min, and the holding time is 1-2 hours.

[0021] In step S5, the pH is 6-8.

[0022] In step S6, the drying temperature is 80°C.

[0023] In step S8, the hydrochloric acid has a mass fraction of 5%, and the washing time is 12 hours.

[0024] In step S9, the drying temperature is 80℃.

[0025] Compared with existing technologies, the method for generating porous carbon from waste paper using phosphoric acid provided by this invention has the following significant advantages:

[0026] 1) Low raw material cost and high value utilization of solid waste: This invention uses widely available and extremely low-cost household waste paper as a precursor raw material, replacing expensive or non-renewable resources such as traditional coal, petroleum coke or coconut shells. This not only significantly reduces the cost of raw materials, but also realizes the resource utilization and high value utilization of solid waste.

[0027] 2) Simplified process and simple pretreatment: Waste paper itself has a natural three-dimensional cellulose network structure, which can be directly used in the activation process without complicated pretreatment, simplifying the overall preparation process and improving production efficiency.

[0028] 3) The activation process is mild and environmentally friendly: Phosphoric acid is used as the activator, which significantly reduces the corrosiveness to production equipment compared to the strong alkali (such as KOH) activation method, thereby reducing equipment investment and maintenance costs and improving production safety. At the same time, it avoids the heavy metal residue problem that may be caused by using activators such as ZnCl2, making the preparation process and the final product more environmentally friendly.

[0029] 4) The product has few impurities and an excellent structure: Through optimized chemical pretreatment (NaOH treatment) and stepwise washing (water washing, acid washing) processes, impurities in the raw materials are effectively removed, ensuring the purity of the product. The resulting porous carbon material has both a high specific surface area and a hierarchical pore structure (as shown in the attached figure, including micropores, mesopores, and macropores). This structure is highly conducive to ion transport and adsorption, enabling it to exhibit excellent performance in fields such as supercapacitors and water treatment (as shown in the attached figure, excellent electrochemical performance).

[0030] 5) Low overall preparation cost and great industrialization potential: Considering factors such as raw material cost, equipment requirements, energy consumption and environmental protection, the overall preparation cost of this invention is low and the raw materials are readily available, which has good prospects for large-scale production and industrial application.

[0031] In summary, this invention utilizes phosphoric acid-activated waste paper to prepare porous carbon materials. This method uses low-cost municipal solid waste as a precursor and a mature and mild phosphoric acid activation process as its core, achieving low-cost, high-yield, tunable pore structure, and surface functionalization of porous carbon materials. This provides an economical and efficient material solution for fields such as supercapacitors, water treatment, and photothermal conversion, while simultaneously promoting the high-value recycling of municipal solid waste. The raw materials used in this invention are readily available and low-cost, enabling high-value utilization of solid waste. It eliminates the need for complex pretreatment, simplifies the preparation process, produces pure components with few impurities, minimizes equipment corrosion, enhances production safety, and combines high specific surface area with a hierarchical pore structure. The overall preparation cost is low, with significant industrialization potential, no heavy metal residues, and strong environmental friendliness. Attached Figure Description

[0032] Figure 1 This is a SEM image of the precursor after preliminary carbonization in Example 3 of the present invention.

[0033] Figure 2 This is an EDS image of the precursor after preliminary carbonization in Example 3 of the present invention.

[0034] Figure 3 This is an EDS image of the precursor C element after preliminary carbonization in Example 3 of the present invention.

[0035] Figure 4 This is an EDS image of the precursor O element after preliminary carbonization in Example 3 of the present invention.

[0036] Figure 5 This is a SEM image of the porous carbon material after activation in Example 3 of the present invention.

[0037] Figure 6 This is an EDS image of the porous carbon material after activation in Example 3 of the present invention.

[0038] Figure 7 This is an EDS image of the C element in the porous carbon material after activation in Example 3 of the present invention.

[0039] Figure 8 This is an EDS image of the O element in the porous carbon material after activation in Example 3 of the present invention.

[0040] Figure 9 This is the current-voltage cycle curve of the battery made of the activated porous carbon material in Example 3 of the present invention.

[0041] Figure 10 This is a charge-discharge curve of the carbonized material battery in Embodiment 6 of the present invention.

[0042] Figure 11 This is a charge-discharge curve of the material battery after activation in Example 6 of the present invention. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0044] Example 1

[0045] A method for generating porous carbon by treating waste paper with phosphoric acid includes the following steps:

[0046] Step S1: Mix waste paper with sodium hydroxide solution; the mass fraction of the NaOH solution is 75%.

[0047] Step S2: Mix the treated waste paper with a phosphoric acid (20% by mass) solution at a 2:1 impregnation ratio. After mixing, rub the waste paper to obtain waste paper uniformly mixed with phosphoric acid solution.

[0048] Step S3: Place the obtained mixture in an oven and dry it at 80°C for 48 hours.

[0049] Step S4: Under a nitrogen atmosphere, the material dried in step S3 is heated to 800°C at a heating rate of 5°C / min and held at that temperature for 1 hour for carbonization.

[0050] Step S5: Wash the obtained material with water to make its pH=6;

[0051] Step S6: Continue to dry the washed material in the oven at 80℃ for 48 hours.

[0052] Step S7: The dried material is activated by passing steam through it. The activation temperature is 800℃, and the temperature is maintained for 1 hour. The temperature is increased at a rate of 5℃ / min, and steam is introduced at a rate of 0.5L / min.

[0053] Step S8: The activated material is acid-washed by preparing a 5wt% dilute hydrochloric acid solution and washing for 12 hours, and finally rinsed with deionized water until neutral.

[0054] Step S9: Place the obtained material in an oven to dry at a temperature of 80°C. After drying, porous carbon is obtained.

[0055] The porous carbon obtained in Example 1 has a specific surface area of ​​1650 m² / g, a total pore volume of 0.6 cm³ / g, and a micropore volume of 0.4 cm³ / g, exhibiting a hierarchical microporous-mesoporous pore structure. Electrochemical testing (1M TEATFB / organic system) showed that the specific capacitance was 150 F / g at a current density of 0.1 A / g, and remained above 70 F / g at 10 A / g, with a capacity retention of 80%, demonstrating excellent rate performance.

[0056] Example 2

[0057] A method for generating porous carbon by treating waste paper with phosphoric acid includes the following steps:

[0058] Step S1: Mix waste paper with sodium hydroxide solution; the mass fraction of the NaOH solution is 75%.

[0059] Step S2: Mix the treated waste paper with a phosphoric acid (20% by mass) solution at a 2:1 impregnation ratio. After mixing, rub the waste paper to obtain waste paper uniformly mixed with phosphoric acid solution.

[0060] Step S3: Place the obtained mixture in an oven and dry it at 80°C for 48 hours.

[0061] Step S4: Under a nitrogen atmosphere, the material dried in step S3 is heated to 800°C at a heating rate of 5°C / min and held at that temperature for 1.5 hours for carbonization.

[0062] Step S5: Wash the obtained material with water to make its pH=7;

[0063] Step S6: Continue to dry the washed material in the oven at 80℃ for 48 hours.

[0064] Step S7: The dried material is activated by passing steam through it. The activation temperature is 800℃, and the temperature is maintained for 2 hours. The temperature is increased at a rate of 5℃ / min, and steam is introduced at a rate of 0.5L / min.

[0065] Step S8: The activated material is acid-washed by preparing a 5wt% dilute hydrochloric acid solution and washing for 12 hours, and finally rinsed with deionized water until neutral.

[0066] Step S9: Place the obtained material in an oven to dry at a temperature of 80°C. After drying, porous carbon is obtained.

[0067] The porous carbon obtained in Example 2 has a specific surface area of ​​1700 m² / g, a total pore volume of 0.65 cm³ / g, and a micropore volume of 0.6 cm³ / g, exhibiting a hierarchical pore structure of micropores-mesopores-macropores. Electrochemical testing (1M TEATFB / organic system) showed that the specific capacitance was 120 F / g at a current density of 0.5 A / g, and remained above 80 F / g at 10 A / g, with a capacity retention of 81%, demonstrating excellent rate performance.

[0068] Example 3,

[0069] A method for generating porous carbon by treating waste paper with phosphoric acid includes the following steps:

[0070] Step S1: Mix waste paper with sodium hydroxide solution; the mass fraction of the NaOH solution is 75%.

[0071] Step S2: Mix the treated waste paper with a phosphoric acid (20% by mass) solution at a 2:1 impregnation ratio. After mixing, rub the waste paper to obtain waste paper uniformly mixed with phosphoric acid solution.

[0072] Step S3: Place the obtained mixture in an oven and dry it at 80°C for 48 hours.

[0073] Step S4: Under a nitrogen atmosphere, the material dried in step S3 is heated to 800°C at a heating rate of 5°C / min and held at that temperature for 1 hour for carbonization.

[0074] Step S5: Wash the obtained material with water to make its pH=8;

[0075] Step S6: Continue to dry the washed material in the oven at 80℃ for 48 hours.

[0076] Step S7: The dried material is activated by passing steam through it. The activation temperature is 800℃, and the temperature is maintained for 3 hours. The temperature is increased at a rate of 5℃ / min, and steam is introduced at a rate of 0.5L / min.

[0077] Step S8: The activated material is acid-washed by preparing a 5wt% dilute hydrochloric acid solution and washing for 12 hours, and finally rinsed with deionized water until neutral.

[0078] Step S9: Place the obtained material in an oven to dry at a temperature of 80°C. After drying, porous carbon is obtained.

[0079] The porous carbon obtained in Example 3 has a specific surface area of ​​1850 m² / g, a total pore volume of 0.6 cm³ / g, and a micropore volume of 0.5 cm³ / g, exhibiting a hierarchical pore structure of micropores-mesopores-macropores. Electrochemical testing (1M TEATFB / organic system) showed that the specific capacitance was 140 F / g at a current density of 0.5 A / g, and remained above 90 F / g at 10 A / g, with a capacity retention of 85%, demonstrating excellent rate performance.

[0080] Example 4

[0081] A method for generating porous carbon by treating waste paper with phosphoric acid includes the following steps:

[0082] Step S1: Mix waste paper with sodium hydroxide solution; the mass fraction of the NaOH solution is 75%.

[0083] Step S2: Mix the treated waste paper with a phosphoric acid (20% by mass) solution at a 2:1 impregnation ratio. After mixing, rub the waste paper to obtain waste paper uniformly mixed with phosphoric acid solution.

[0084] Step S3: Place the obtained mixture in an oven and dry it at 80°C for 48 hours.

[0085] Step S4: Under a nitrogen atmosphere, the material dried in step S3 is heated to 800°C at a heating rate of 5°C / min and held at that temperature for 2 hours for carbonization.

[0086] Step S5: Wash the obtained material with water to make its pH=6;

[0087] Step S6: Continue to dry the washed material in the oven at 80℃ for 48 hours.

[0088] Step S7: The dried material is activated by passing steam through it. The activation temperature is 800℃, and the temperature is maintained for 1 hour. The temperature is increased at a rate of 5℃ / min, and steam is introduced at a rate of 0.5L / min.

[0089] Step S8: The activated material is acid-washed with a 5wt% dilute hydrochloric acid solution for 12 hours, and finally rinsed with deionized water until neutral.

[0090] Step S9: Place the obtained material in an oven to dry at a temperature of 80°C. After drying, porous carbon is obtained.

[0091] The porous carbon obtained in Example 4 has a specific surface area of ​​1900 m² / g, a total pore volume of 0.7 cm³ / g, and a micropore volume of 0.6 cm³ / g, exhibiting a hierarchical microporous-mesoporous pore structure. Electrochemical testing (1M TEATFB / organic system) showed that the specific capacitance was 150 F / g at a current density of 0.5 A / g, and remained above 85 F / g at 10 A / g, with a capacity retention of 81%, demonstrating excellent rate performance.

[0092] Example 5

[0093] A method for generating porous carbon by treating waste paper with phosphoric acid includes the following steps:

[0094] Step S1: Mix waste paper with sodium hydroxide solution; the mass fraction of the NaOH solution is 75%.

[0095] Step S2: Mix the treated waste paper with a phosphoric acid (20% by mass) solution at a 2:1 impregnation ratio. After mixing, rub the waste paper to obtain waste paper uniformly mixed with phosphoric acid solution.

[0096] Step S3: Place the obtained mixture in an oven and dry it at 80°C for 48 hours.

[0097] Step S4: Under a nitrogen atmosphere, the material dried in step S3 is heated to 800°C at a heating rate of 5°C / min and held at that temperature for 2 hours for carbonization.

[0098] Step S5: Wash the obtained material with water to make its pH=7.5;

[0099] Step S6: Continue to dry the washed material in the oven at 80℃ for 48 hours.

[0100] Step S7: The dried material is activated by passing steam through it. The activation temperature is 800℃, and the temperature is maintained for 2 hours. The temperature is increased at a rate of 5℃ / min, and steam is introduced at a rate of 0.5L / min.

[0101] Step S8: The activated material is acid-washed by preparing a 5wt% dilute hydrochloric acid solution and washing for 12 hours, and finally rinsed with deionized water until neutral.

[0102] Step S9: Place the obtained material in an oven to dry at a temperature of 80°C. After drying, porous carbon is obtained.

[0103] The porous carbon obtained in Example 5 has a specific surface area of ​​1700 m² / g, a total pore volume of 0.5 cm³ / g, and a micropore volume of 0.3 cm³ / g, exhibiting a hierarchical microporous-mesoporous pore structure. Electrochemical testing (1M TEATFB / organic system) showed that the specific capacitance was 110 F / g at a current density of 0.5 A / g, and remained above 75 F / g at 10 A / g, with a capacity retention of 80%, demonstrating excellent rate performance.

[0104] Example 6

[0105] A method for generating porous carbon by treating waste paper with phosphoric acid includes the following steps:

[0106] Step S1: Mix waste paper with sodium hydroxide solution; the mass fraction of the NaOH solution is 75%.

[0107] Step S2: Mix the treated waste paper with a phosphoric acid (20% by mass) solution at a 2:1 impregnation ratio. After mixing, rub the waste paper to obtain waste paper uniformly mixed with phosphoric acid solution.

[0108] Step S3: Place the obtained mixture in an oven and dry it at 80°C for 48 hours.

[0109] Step S4: Under a nitrogen atmosphere, the material dried in step S3 is heated to 800°C at a heating rate of 5°C / min and held at that temperature for 2 hours for carbonization.

[0110] Step S5: Wash the obtained material with water to make its pH=8;

[0111] Step S6: Continue to dry the washed material in the oven at 80℃ for 48 hours.

[0112] Step S7: The dried material is activated by passing steam through it. The activation temperature is 800℃, and the temperature is maintained for 3 hours. The temperature is increased at a rate of 5℃ / min, and steam is introduced at a rate of 0.5L / min.

[0113] Step S8: The activated material is acid-washed with a 5wt% dilute hydrochloric acid solution for 12 hours, and finally rinsed with deionized water until neutral.

[0114] Step S9: Place the obtained material in an oven to dry at a temperature of 80°C. After drying, porous carbon is obtained.

[0115] The porous carbon obtained in Example 6 has a specific surface area of ​​1750 m² / g, a total pore volume of 0.5 cm³ / g, and a micropore volume of 0.4 cm³ / g, exhibiting a hierarchical pore structure of micropores-mesopores-macropores. Electrochemical testing (1M TEATFB / organic system) showed that the specific capacitance was 120 F / g at a current density of 0.5 A / g, and remained above 80 F / g at 10 A / g, with a capacity retention of 78%, demonstrating excellent rate performance.

[0116] See Figure 1 ,from Figure 1 It can be seen that it exhibits an irregular sheet-like / block-like morphology, retaining the original layered and wrinkled skeleton of waste paper cellulose fibers. However, after high-temperature activation, the fibers shrink, carbonize, and etch, becoming denser and more brittle, with a large number of micropores / mesoporosis visible on the surface.

[0117] See Figure 2 ,from Figure 2 It can be seen that after carbonization, C and O elements are evenly distributed on the sample surface.

[0118] See Figure 3-4 ,from Figure 3-4 As can be seen, C and O visually demonstrate that the carbon skeleton of phosphoric acid activated waste paper-based porous carbon is continuous, uniform, and has well-developed pores.

[0119] See Figure 5 ,from Figure 5 It can be seen that the surface of carbon sheets / carbon fibers is rough and uneven, covered with micropores / small pores, and there are a large number of gaps between the sheets and fibers, forming a three-dimensional interconnected network of pores. Although the fibers and sheets have been carbonized and activated, the overall structure is intact and has not collapsed severely.

[0120] See Figure 6 ,from Figure 6 It can be seen that C and O elements are evenly distributed on the surface of the material.

[0121] See Figure 7 ,from Figure 7It can be seen that carbon elements continuously and uniformly cover the sample area, and the red signal is strong and uniformly distributed, indicating that the main body of the sample is a carbon skeleton.

[0122] See Figure 8 ,from Figure 8 It can be seen that oxygen is uniformly and diffusely distributed throughout the sample area, without obvious local enrichment or depletion, which is highly consistent with the distribution of the carbon skeleton.

[0123] See Figure 9 ,from Figure 9 It can be seen that as the scan rate increases from 10 mV... . s −1 Increased to 300 mV . s −1 The overall current density of the curves increased significantly, and the curves at all scan rates showed a "bulging" or "rectangular" shape without sharp redox peaks. In the high potential region (2.0 V to 2.5 V), the current density increased sharply, and the curves showed a clear "upward" trend. Comparing the curves at different scan rates, the increasing trend of current density remained consistent, and the curve shape did not undergo serious distortion. This indicates that the charge storage mechanism of this material is dominated by surface control / pseudocapacitive behavior, with fast ion transport dynamics and good fast charge and discharge capabilities.

[0124] See Figure 10-11 ,from Figure 10 and 11 As can be seen, the charge-discharge segments of all curves are approximately straight lines, without obvious voltage plateaus or bends, indicating that the sample mainly exhibits double-layer capacitance or surface pseudocapacitance, with rapid ion adsorption and desorption on the electrode surface / inside the pores, and no obvious diffusion-controlled battery-like reaction; the high linearity indicates that the material maintains good capacitive reversibility at various current densities. From 0.1 A g -1 Up to 50 A g -1 The sample was still able to complete charging and discharging, indicating that it has excellent rate performance and can be charged and discharged quickly under high current.

Claims

1. A method for generating porous carbon by treating waste paper with phosphoric acid, characterized in that, Includes the following steps: Step S1: Mix waste paper with sodium hydroxide solution; Step S2: Mix the material obtained in step S1 with the phosphoric acid solution according to the impregnation ratio, and knead to obtain waste paper uniformly mixed with phosphoric acid solution. Step S3: Dry the mixture obtained in step S2 for 48 hours; Step S4: Under a nitrogen atmosphere, the material obtained in step S3 is heated and held at that temperature to undergo carbonization. Step S5: Wash the material obtained in step S4 with deionized water until pH=6-8; Step S6: Dry the material obtained in step S5 for 48 hours; Step S7: Activate the material obtained in step S6 by introducing steam at 800℃, wherein the heating rate is 5℃ / min, the steam introduction rate is 0.5L / min, and the holding time is 1-3h. Step S8: Wash the material obtained in step S7 with hydrochloric acid, and then rinse with deionized water until pH=6-8. Step 9: Dry the material obtained in step S8 to obtain porous carbon.

2. The method for generating porous carbon from waste paper using phosphoric acid according to claim 1, characterized in that, In step S1, the NaOH solution has a mass fraction of 75%.

3. The method for generating porous carbon from waste paper using phosphoric acid according to claim 1, characterized in that, In step S2, the impregnation ratio is 2:1; the mass fraction of the phosphoric acid solution is 20%.

4. The method for generating porous carbon from waste paper using phosphoric acid according to claim 1, characterized in that: In step S3, the drying temperature is 80°C.

5. The method for generating porous carbon from waste paper using phosphoric acid according to claim 1, characterized in that, In step S4, the carbonization temperature is 800℃, the heating rate is 5℃ / min, and the holding time is 1-2 hours.

6. The method for generating porous carbon from waste paper using phosphoric acid according to claim 1, characterized in that, In step S6, the drying temperature is 80°C.

7. The method for generating porous carbon from waste paper using phosphoric acid according to claim 1, characterized in that, In step S8, the hydrochloric acid has a mass fraction of 5%, and the washing time is 12 hours.

8. The method for generating porous carbon from waste paper using phosphoric acid according to claim 1, characterized in that, In step S9, the drying temperature is 80℃.

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