A catalyst for rubber asphalt flue gas purification and its preparation method

Abstract

The present invention belongs to the technical field of asphalt flue gas purification and discloses a catalyst for rubber asphalt flue gas purification and a preparation method thereof. The preparation method comprises the following steps: using crop waste as a carbon source, drying and crushing the crop waste, and then carbonizing the crop to obtain biochar; mixing the biochar with sodium amide and then activating the biochar to obtain modified biochar; mixing the modified biochar with an acid solution, then hydrothermally reacting the crop waste, filtering, washing, and drying the crop waste to obtain a precursor; placing the precursor in a metal salt solution and ultrasonically treating the mixture to obtain a mixed solution; adding ascorbic acid to the mixed solution, stirring the mixture, filtering, washing, and drying the mixture to obtain the catalyst for rubber asphalt flue gas purification. The catalyst has low preparation cost, a convenient preparation process, and high preparation efficiency, and has good application prospects and industrialization potential. The catalyst prepared by the present invention can quickly and efficiently purify pollutants such as sulfur oxides, nitrogen oxides, and hydrogen sulfide in rubber asphalt flue gas.

Description

Technical Field

[0001] The present invention relates to the technical field of asphalt flue gas purification, and in particular to a catalyst for purifying rubber asphalt flue gas and a preparation method thereof. Background Art

[0002] With the rapid development of the transportation industry, increasing traffic loads and volumes have accelerated the deterioration of asphalt pavements. Ordinary asphalt pavements no longer meet current highway grade requirements. Research has found that crushing waste tires into rubber powder and adding it to asphalt not only improves the high-temperature stability, fatigue life, and crack resistance of asphalt pavements, but also provides a green method for recycling waste tires.

[0003] Although rubber asphalt has obvious advantages, compared with ordinary asphalt, rubber asphalt produces more toxic and harmful fumes (such as volatile organic compounds (VOCs), hydrogen sulfide (H2S), sulfur oxides (SO)) during the production and mixing process. x , nitrogen oxides NO x The release of these fumes not only adversely affects the respiratory system of on-site workers but also poses a serious threat to the ecological environment. Therefore, before being released into the atmosphere, rubber asphalt fumes must be purified to ensure they meet environmental protection requirements.

[0004] In order to solve the above problems, the existing technology has proposed the following treatment methods to avoid or reduce the impact of pollutants in flue gas on the environment: such as mechanical separation method, condensation method, filtration method, high-temperature combustion method and low-temperature plasma method. However, the existing technology usually has the following defects: 1) It only has a good purification effect on organic pollutants and dust particles in flue gas, and cannot effectively purify small molecular pollutants such as hydrogen sulfide, sulfur oxides, nitrogen oxides, etc. in the flue gas; 2) When performing the flue gas purification reaction, the flue gas needs to be passed through different reaction units for purification treatment separately, and the treatment process is complicated and time-consuming; 3) The raw materials of the prepared flue gas purification catalyst are expensive, and the treatment process cost is high, which is not conducive to engineering promotion and application.

[0005] To this end, the present invention provides a catalyst for purifying rubber asphalt flue gas and a preparation method thereof. Summary of the Invention

[0006] In order to solve the problems of the above-mentioned prior art such as complex treatment process, long time consumption, and expensive catalytic material cost, the present invention provides a catalyst for rubber asphalt flue gas purification and a preparation method thereof.

[0007] The catalyst for flue gas purification of rubber asphalt and the preparation method thereof of the present invention are achieved through the following technical solutions:

[0008] The first object of the present invention is to provide a method for preparing a catalyst for flue gas purification of rubber asphalt, comprising the following steps:

[0009] Step 1: using crop waste as a carbon source, drying and crushing it, and then carbonizing it to obtain biochar;

[0010] Wherein, the crop waste is any one of corn straw, wheat straw, and sugarcane bagasse;

[0011] Step 2, mixing the biochar with sodium amide and performing activation treatment to obtain modified biochar;

[0012] Step 3, mixing the modified biochar with the acid solution, performing a hydrothermal reaction, filtering, washing, and drying to obtain a precursor;

[0013] Step 4, placing the precursor in a metal salt solution and ultrasonically treating it to obtain a mixed solution;

[0014] Step 5: Place ascorbic acid and gelatin in an aqueous solvent and adjust the pH to 13.8-14 with alkali solution to obtain a reducing agent; and heat the reducing agent to 82-88° C. and then add it to the mixed solution under stirring. After stirring, filtering, washing, and drying, the rubber asphalt flue gas purification catalyst is obtained.

[0015] Furthermore, the metal salt solution is a divalent copper ion solution.

[0016] Furthermore, the ratio of the metal salt solution to the precursor is 20 mL: 0.2-0.5 g;

[0017] The concentration of the metal salt solution is 0.02-0.04 mol / L.

[0018] Furthermore, in the reducing agent, the concentration of ascorbic acid is 0.05 to 0.2 mol / L, and the mass concentration of gelatin is 0.1% to 5%;

[0019] The volume ratio of the reducing agent to the mixed solution is 18 to 22:1.

[0020] Furthermore, the mass ratio of the biochar to the sodium amide is 2 to 5:1.

[0021] Furthermore, the acid solution is hydrochloric acid or nitric acid;

[0022] The ratio of the acid solution to the modified biochar is 15-25 mL:1 g;

[0023] The acid concentration in the acid solution is 0.1-0.5 mol / L.

[0024] Furthermore, the carbonization treatment is carried out in an N2 or Ar atmosphere, and the carbonization temperature is 350 to 750°C, and the carbonization time is 0.5 to 3.5 hours.

[0025] Furthermore, the activation treatment is carried out in an N2 or Ar atmosphere, and the activation temperature is 300-500°C, and the activation time is 1-3 hours.

[0026] Furthermore, the temperature of the hydrothermal reaction is 70-90° C., and the reaction time is 6-12 hours.

[0027] Furthermore, in step 4, the ultrasonic frequency is 35 to 45 kHz, and the ultrasonic time is 10 to 30 minutes.

[0028] Furthermore, in step 5, the stirring rate of the stirring treatment is 300 to 500 r / min, and the stirring time is 8 to 16 hours.

[0029] Furthermore, in step 1, the drying temperature is 40 to 70° C., and the drying time is 8 to 24 hours.

[0030] Furthermore, in step 3, the drying temperature is 60 to 105° C., and the drying time is 8 to 24 hours.

[0031] Furthermore, in step 5, the drying temperature is 20 to 45° C., and the drying time is 8 to 24 hours.

[0032] The second object of the present invention is to provide a catalyst for purifying flue gas of rubber asphalt prepared by the above preparation method.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention preferably uses crop waste as a carbon source, and the crop waste can be selected from any one of corn straw, wheat straw, and sugarcane bagasse. This not only provides a sufficient carbon source, but also alleviates the environmental pollution and resource waste caused by the accumulation of waste crops.

[0035] The present invention preferably uses sodium amide as an activating agent to activate the biochar. Sodium amide not only further promotes the formation of pores in the carbon-based material, but also reduces the activation temperature, enabling activation of the biochar at a lower temperature, thereby obtaining a porous carbon-based material. Furthermore, sodium amide can introduce nitrogen atoms into the carbon-based material skeleton during the activation process, thereby simultaneously achieving nitrogen doping of the carbon-based material during the activation process, thereby obtaining a nitrogen-doped porous carbon-based material.

[0036] The present invention further modifies the modified biochar by acid solution, which can further increase the pores of the carbon-based material and increase the functional groups (-C-O, C=O, -O-C=O, etc.) on the surface of the carbon-based material. On the basis of doping nitrogen atoms in the carbon-based material, the construction of oxygen-containing groups is further realized, and then through the synergistic effect of nitrogen doping and oxygen-containing functional groups, the carbon-based material is helped to further catalyze and purify nitrogen oxides in flue gas.

[0037] The present invention preferably uses a solution containing divalent copper ions as the metal salt solution and employs ultrasonic treatment to evenly disperse the precursor within the metal salt solution. This allows the copper ions in the metal salt to evenly surround the precursor, thereby facilitating the subsequent uniform conversion of the metal ions to elemental copper on the precursor surface. Furthermore, the addition of elemental copper further enhances the precursor's adsorption capacity for sulfur oxides and hydrogen sulfide, thereby improving the purification of asphalt fumes.

[0038] The present invention preferably uses ascorbic acid as a reducing agent, which is added to the mixed solution to reduce the metallic copper ions to metallic copper, and uniformly precipitates them on the surface of the precursor to form a carbon-based material with nano-copper on the surface, namely, a catalyst for rubber asphalt flue gas purification.

[0039] The present invention adopts a step-by-step directional construction strategy of nitrogen doping and adding oxygen-containing functional groups, which can achieve an excellent pore structure while enabling nitrogen atoms and oxygen-containing functional groups to work synergistically, thereby purifying small molecular pollutants such as sulfur oxides and nitrogen oxides in rubber asphalt flue gas.

[0040] The preparation method of the present invention is easy to operate, has low preparation costs, mild reaction conditions, high reaction efficiency, and can rely on existing mature physical activation processes, thus having good application prospects and industrial potential. Furthermore, the rubber asphalt flue gas purification catalyst prepared by the present invention has large porosity, specific surface area, and active sites, enabling rapid and efficient purification of pollutants such as hydrogen sulfide and nitrogen oxides. Furthermore, the rubber asphalt flue gas purification catalyst prepared by the present invention is high-temperature wear-resistant and has a long service life, allowing it to be used as a catalyst for long-term flue gas purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 These are the test results of H2S inhibition rates of the rubber asphalt flue gas purification catalysts prepared in Examples 1-13 and Comparative Examples 1-3. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0043] The present invention provides a catalyst for purifying flue gas from rubber asphalt, and the preparation method thereof is as follows:

[0044] Step 1: using crop waste as a carbon source, drying and crushing it, and then carbonizing it to obtain biochar;

[0045] It should be noted that, considering the cost and availability of raw materials, the present invention prefers crop waste as a carbon source, and the crop waste can be selected from any one of corn straw, wheat straw, and sugarcane bagasse. This not only provides a sufficient carbon source but also alleviates the environmental pollution and resource waste caused by the storage of crop waste.

[0046] The present invention preferably first dries the crop waste to remove excess moisture, then crushes it and passes it through a 100-mesh sieve to form crop waste pellets, thereby making it easier to form a porous carbon-based material during the carbonization process. The drying temperature is 40 to 70°C and the drying time is 8 to 24 hours. The carbonization process is carried out in an N2 or Ar atmosphere at a carbonization temperature of 350 to 750°C and a carbonization time of 0.5 to 3.5 hours.

[0047] Step 2, mixing the biochar with sodium amide and performing activation treatment to obtain modified biochar;

[0048] It should be noted that the present invention preferably uses sodium amide as an activating agent to activate the biochar. Sodium amide not only further promotes the formation of pores in the carbon-based material, but also reduces the activation temperature, allowing the biochar to be activated at a lower temperature, thereby obtaining a porous carbon-based material. Furthermore, sodium amide can introduce nitrogen atoms into the carbon-based material skeleton during the activation process, thereby simultaneously nitrogen-doping the carbon-based material and obtaining a nitrogen-doped porous carbon-based material. Nitrogen doping increases the alkalinity of the activated carbon, improves its surface electronic structure, and enhances its chemical activity, thereby enhancing the activated carbon's adsorption capacity for acidic pollutants (such as hydrogen sulfide). Furthermore, the present invention preferably uses a mass ratio of biochar to sodium amide of 2 to 5:1; the activation process is carried out in an N2 or Ar atmosphere, the activation temperature is 300 to 500°C, and the activation time is 1 to 3 hours.

[0049] Step 3, mixing the modified biochar with the acid solution, performing a hydrothermal reaction, filtering, washing, and drying to obtain a precursor;

[0050] It should be noted that the preferred acid used in the present invention is hydrochloric acid or nitric acid, with the ratio of acid to modified biochar being 15-25 mL:1 g; and the acid concentration in the acid is 0.1-0.5 mol / L. Further modification of the modified biochar with the acid can further increase the pores of the carbon-based material and increase the number of functional groups (-C-O, C=O, -O-C=O, etc.) on its surface. Furthermore, by doping the carbon-based material with nitrogen atoms, oxygen-containing groups are further constructed. The synergistic effect of nitrogen doping and oxygen-containing functional groups further facilitates the catalytic purification of nitrogen oxides by the carbon-based material. The hydrothermal reaction temperature is 70-90°C, and the reaction time is 6-12 hours. The drying temperature is 60-105°C, and the drying time is 8-24 hours.

[0051] Step 4, placing the precursor in a metal salt solution and ultrasonically treating it to obtain a mixed solution;

[0052] It should be noted that the present invention preferably uses a solution containing divalent copper ions as the metal salt solution, such as copper nitrate, copper chloride and copper sulfate solution, preferably a copper chloride solution; and the amount of the metal salt solution to the precursor is 20mL: 0.2~0.5g; and the concentration of the metal salt solution is 0.02~0.04mol / L. And the present invention preferably adopts ultrasonic treatment to uniformly disperse the precursor in the metal salt solution, so that the metal copper ions in the metal salt uniformly surround the precursor, thereby facilitating the subsequent metal ions to uniformly convert into metallic copper on the surface of the precursor. And after being loaded with metallic copper, the adsorption capacity for hydrogen sulfide can be further improved, thereby helping to improve the desulfurization effect. And in order to ensure the effect of ultrasonic treatment, the preferred ultrasonic frequency of the present invention is 35~45kHz, and the ultrasonic time is 10~30min.

[0053] Step 5: placing ascorbic acid and gelatin in an aqueous solvent and adjusting the pH to 13.8-14 with an alkali solution to obtain a reducing agent; heating the reducing agent to 82-88° C. and adding the reducing agent to the mixed solution under stirring, stirring, filtering, washing, and drying to obtain the rubber asphalt flue gas purification catalyst;

[0054] It should be noted that the present invention preferably uses ascorbic acid as a reducing agent. Adding it to the mixed solution, in an alkaline environment, reduces metallic copper ions to elemental copper and uniformly precipitates it on the surface of the precursor, forming a carbon-based material with nano-copper on its surface, namely, a catalyst for rubber asphalt flue gas purification. The preferred reducing agent of the present invention comprises an ascorbic acid concentration of 0.05-0.2 mol / L and a gelatin concentration of 0.1%-5%. The volume ratio of the reducing agent to the mixed solution is 1:18-22. To ensure uniform reduction, the stirring rate during the stirring process is 300-500 rpm, and the stirring time is 8-16 hours. The present invention also preferably uses an alkaline solution and deionized water as the detergents for the washing process, until the washing solution is neutral. The alkaline solution used can be selected from sodium hydroxide solution or potassium hydroxide solution. The drying temperature is 20-45°C, and the drying time is 8-24 hours.

[0055] Example 1

[0056] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method is as follows:

[0057] Step 1: Prepare biochar

[0058] 1) Preparation of crop waste pellets

[0059] Sugarcane bagasse was used as a carbon source and dried in an oven at 60°C for 12 h. It was then pulverized using a pulverizer, and the pulverized product was passed through a 100-mesh sieve to obtain crop waste particles.

[0060] 2) Carbonized crop waste pellets

[0061] The crop waste particles obtained above were heated to 500° C. in an Ar atmosphere, kept at this temperature for 2 h, and cooled to room temperature to obtain biochar.

[0062] Step 2: Modify the biochar with sodium amide

[0063] The biochar obtained above was mixed with sodium amide at a mass ratio of 2.5:1 and then ground for 15 minutes to refine the grains and mix them uniformly to obtain a mixed material;

[0064] Subsequently, the mixture was activated in an Ar atmosphere, heated to 400°C and kept warm for 2 h, and then cooled to room temperature to obtain modified biochar.

[0065] Step 3: Prepare the precursor

[0066] Take 1 g of the modified biochar prepared above, place it in 20 mL of a 0.2 mol / L hydrochloric acid solution, and stir it at a stirring rate of 300 r / min for 10 min to mix it evenly. Then transfer it to a polytetrafluoroethylene liner, put it into a kettle, and react at 80°C for 8 h. After cooling to room temperature, the reaction product is filtered and washed alternately with ethanol and deionized water until the washing liquid is neutral. Then, it is dried at 85°C for 12 h to obtain a precursor.

[0067] Step 4: Preparation of catalyst

[0068] The precursor obtained above was ground in a mortar for 10 minutes to obtain a precursor powder; 0.3 g of the precursor powder prepared above was placed in 20 mL of a 0.03 mol / L copper chloride solution, and ultrasonically treated at an ultrasonic frequency of 40 kHz for 20 minutes to obtain a mixed solution.

[0069] Ascorbic acid and gelatin are placed in an aqueous solvent to prepare a solution with an ascorbic acid concentration of 0.1 mol / L and a gelatin mass concentration of 2%. The reducing agent is obtained by adjusting the pH to 14 with a 6 mol / L sodium hydroxide solution and heating the solution to 86°C for use.

[0070] The mixed solution is stirred at a rate of 400 r / min and heated to 80°C, and then, under the action of heating and stirring, a heated reducing agent is added thereto, and the volume ratio of the added reducing agent to the mixed solution is 1:20 to obtain a mixed slurry; the mixed slurry is continued to be stirred at a rate of 400 r / min for 12 hours at a temperature of 85°C. After cooling to room temperature, the reaction product is filtered and washed alternately with ethanol and deionized water until the washing liquid is neutral; and then dried at a temperature of 40°C for 12 hours to obtain a rubber asphalt flue gas purification catalyst.

[0071] Example 2

[0072] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0073] In this embodiment, the mass ratio of biochar to sodium amide is 2:1; the activation treatment temperature is 300° C., and the activation time is 3 hours.

[0074] Example 3

[0075] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0076] In this embodiment, the mass ratio of biochar to sodium amide is 5:1; the activation treatment temperature is 500° C., and the activation time is 1 hour.

[0077] Example 4

[0078] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0079] In this embodiment, the ratio of the acid solution to the modified biochar is 15 mL:1 g; and the concentration of the acid in the acid solution is 0.1 mol / L.

[0080] Example 5

[0081] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0082] In this embodiment, the ratio of the acid solution to the modified biochar is 25 mL:1 g; and the concentration of the acid in the acid solution is 0.5 mol / L.

[0083] Example 6

[0084] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0085] In this embodiment, the ratio of the copper chloride solution to the precursor is 20 mL:0.2 g; and the concentration of the metal salt solution is 0.02 mol / L.

[0086] Example 7

[0087] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0088] In this embodiment, the ratio of the copper chloride solution to the precursor is 20 mL:0.5 g; and the concentration of the metal salt solution is 0.04 mol / L.

[0089] Example 8

[0090] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0091] In this embodiment, the ultrasonic frequency is 35 kHz and the ultrasonic time is 10 minutes.

[0092] Example 9

[0093] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0094] In this embodiment, the ultrasonic frequency is 45 kHz and the ultrasonic time is 30 minutes.

[0095] Example 10

[0096] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0097] In this embodiment, the concentration of ascorbic acid in the reducing agent is 0.05 mol / L, the mass concentration of gelatin is 0.1%; and the volume ratio of the reducing agent to the mixed solution is 1:18.

[0098] Example 11

[0099] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0100] In this embodiment, the concentration of ascorbic acid in the reducing agent is 0.2 mol / L, the mass concentration of gelatin is 5%, and the volume ratio of the reducing agent to the mixed solution is 1:22.

[0101] Example 12

[0102] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0103] In this embodiment, corn stalks are used as the carbon source during the carbonization treatment.

[0104] Example 13

[0105] This embodiment provides a catalyst for purifying flue gas from rubber asphalt, and its preparation method differs from that of Example 1 only in that:

[0106] In this embodiment, wheat straw is used as the carbon source during the carbonization treatment.

[0107] Comparative Example 1

[0108] The difference between this comparative example and Example 1 is only that:

[0109] In this comparative example, no sodium amide was added for activation treatment, and the biochar was directly subjected to hydrothermal reaction with the acid solution.

[0110] Comparative Example 2

[0111] The difference between this comparative example and Example 1 is only that:

[0112] In this comparative example, no acid solution was added, and the modified biochar was directly placed in the metal salt solution.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 1 is only that:

[0115] In this comparative example, no metal salt solution or reducing agent is added, that is, no nano-metal single substance layer is coated on the surface of the precursor material.

[0116] Experimental part

[0117] (1) SO2 and NO removal efficiency test

[0118] 10g of each of the rubber asphalt flue gas purification catalysts prepared in Examples 1-13 and Comparative Examples 1-3 were weighed and placed in a fixed reactor. The temperature was raised to 120°C, and simulated flue gas was introduced for testing. The simulated flue gas consisted of a mixture of SO2 (3%), NO (2%), and O2 (10%) at a flow rate of 0.5 L / min, with the balance gas being N2. The SO2 and NO removal efficiencies of the rubber asphalt flue gas purification catalysts prepared in Examples 1-13 and Comparative Examples 1-3 were tested. The test results are shown in Table 1.

[0119] Table 1 SO2 and NO removal efficiency test

[0120]

[0121]

[0122] As can be seen from Table 1, the catalyst for flue gas purification of rubber asphalt prepared in Example 1 of the present invention has the best treatment effect, with an SO2 removal efficiency of up to 87.5% and an NO removal efficiency of over 70%. Furthermore, by comparing the test results of Examples 1-13, it can be seen that the effective flue gas purification effect achieved by the present invention is not achieved by a single component or step, but is achieved by the various components and steps being carried out in sequence. The technical solution of the present invention is a whole, and its technical effect is the embodiment of its organic combination. Furthermore, by comparing the test results of Example 1 and Comparative Examples 1-3, it can be seen that the modification treatment of biochar with sodium amide has the greatest impact on the efficiency of flue gas purification, followed by the impact of acid treatment, and the least impact of metal salts and reducing agents.

[0123] (2) Hydrogen sulfide inhibition rate test

[0124] The present invention weighed 10g of the rubber asphalt flue gas purification catalyst prepared in Examples 1-13 and Comparative Examples 1-3 to test the H2S inhibition rate. The test steps are as follows: 250g of rubber asphalt was poured into a three-necked flask and heated at a constant temperature. The rubber asphalt flue gas purification catalyst prepared in Examples 1-13 and Comparative Examples 1-3 was placed in a fixed reactor at the rear of the device. The heating temperature was 200°C, the heating time was 1h, the carrier gas was N2, and the test results were as follows: Figure 1shown.

[0125] Depend on Figure 1 It can be seen that the catalyst for flue gas purification of rubber asphalt prepared in Example 1 of the present invention has the best hydrogen sulfide inhibition effect, with an inhibition rate of over 60% at 200°C. Furthermore, a comparison of the test results of Examples 1-13 shows that the effective hydrogen sulfide inhibition effect achieved by the present invention is not achieved by a single component or step, but rather by the sequential implementation of various components and steps. The technical solution of the present invention is a holistic whole, and its technical effect is the embodiment of its organic combination. Furthermore, a comparison of the test results of Example 1 and Comparative Examples 1-3 shows that sodium amide modification of biochar has the greatest impact on its hydrogen sulfide inhibition effect, followed by acid treatment, and the least impact of metal salts and reducing agents.

[0126] Obviously, the above embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for flue gas purification of rubber asphalt, characterized in that: The following steps are involved: Step 1: using crop waste as a carbon source, drying and crushing it, and then carbonizing it to obtain biochar; Wherein, the crop waste is any one of corn straw, wheat straw, and sugarcane bagasse; Step 2, mixing the biochar with sodium amide and performing activation treatment to obtain modified biochar; Step 3, mixing the modified biochar with the acid solution, performing a hydrothermal reaction, filtering, washing, and drying to obtain a precursor; Step 4, placing the precursor in a metal salt solution and ultrasonically treating it to obtain a mixed solution; Step 5: placing ascorbic acid and gelatin in an aqueous solvent and adjusting the pH to 13.8-14 with an alkali solution to obtain a reducing agent; heating the reducing agent to 82-88° C. and adding the reducing agent to the mixed solution under stirring, stirring, filtering, washing, and drying to obtain the rubber asphalt flue gas purification catalyst; The mass ratio of biochar to sodium amide is 2-5:1; Activation temperature is 300~500℃; The metal salt solution is a divalent copper ion solution.

2. The preparation method according to claim 1, wherein The ratio of the metal salt solution to the precursor is 20 mL: 0.2-0.5 g; The concentration of the metal salt solution is 0.02-0.04 mol / L.

3. The preparation method according to claim 1, wherein In the reducing agent, the concentration of ascorbic acid is 0.05-0.2 mol / L, and the mass concentration of gelatin is 0.1%-5%; The volume ratio of the reducing agent to the mixed solution is 1:18-22.

4. The preparation method according to claim 1, wherein The acid solution is hydrochloric acid or nitric acid; The ratio of the acid solution to the modified biochar is 15-25 mL: 1 g; The acid concentration in the acid solution is 0.1-0.5 mol / L.

5. The preparation method according to claim 1, wherein The carbonization treatment is carried out in an N2 or Ar atmosphere, with a carbonization temperature of 350-750°C and a carbonization time of 0.5-3.5h.

6. The preparation method according to claim 1, wherein The activation treatment is carried out in an N2 or Ar atmosphere, and the activation time is 1 to 3 hours.

7. The preparation method according to claim 1, wherein The temperature of the hydrothermal reaction is 70-90° C., and the reaction time is 6-12 hours.

8. The preparation method according to claim 1, wherein In step 4, the ultrasonic frequency is 35-45 kHz, and the ultrasonic time is 10-30 min; In step 5, the stirring temperature is 80-85° C., the stirring rate is 300-500 r / min, and the stirring time is 8-16 h.

9. A catalyst for purifying flue gas from rubber asphalt prepared by the preparation method according to any one of claims 1 to 8.

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