CN116673028A - Catalyst for purifying flue gas of rubber asphalt and preparation method thereof - Google Patents

Catalyst for purifying flue gas of rubber asphalt and preparation method thereof Download PDF

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Publication number
CN116673028A
CN116673028A CN202310632880.3A CN202310632880A CN116673028A CN 116673028 A CN116673028 A CN 116673028A CN 202310632880 A CN202310632880 A CN 202310632880A CN 116673028 A CN116673028 A CN 116673028A
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flue gas
preparation
catalyst
biochar
rubber asphalt
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谢娟
赵勖丞
贺文
余帆
卢真真
李帅辉
丁哲宇
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Changsha University of Science and Technology
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Changsha University of Science and Technology
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8621—Removing nitrogen compounds
    • B01D53/8625—Nitrogen oxides
    • B01D53/8628—Processes characterised by a specific catalyst
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    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/48—Sulfur compounds
    • B01D53/52—Hydrogen sulfide
    • B01D53/523—Mixtures of hydrogen sulfide and sulfur oxides
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/46—Removing components of defined structure
    • B01D53/54—Nitrogen compounds
    • B01D53/56—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/8603—Removing sulfur compounds
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    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/72—Copper
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B01J37/10—Heat treatment in the presence of water, e.g. steam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/16—Reducing
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    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/34—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation
    • B01J37/341—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation
    • B01J37/343—Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves ; Ionic sputtering; Flame or plasma spraying; Particle radiation making use of electric or magnetic fields, wave energy or particle radiation of ultrasonic wave energy
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Abstract

The 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, wherein the preparation method comprises the following steps: taking crop wastes as a carbon source, drying and crushing, and carbonizing to obtain biochar; uniformly mixing the biochar with sodium amide, and performing activation treatment to obtain modified biochar; uniformly mixing the modified biochar with acid liquor, performing hydrothermal reaction, filtering, washing and drying to obtain a precursor; placing the precursor in a metal salt solution, and performing ultrasonic treatment to obtain a mixed solution; adding ascorbic acid into the mixed solution, stirring, filtering, washing and drying to obtain the catalyst for purifying the rubber asphalt flue gas. The preparation method has the advantages of low preparation cost, convenient preparation process, high preparation efficiency and good application prospect and industrialization potential; the catalyst prepared by the invention can quickly and efficiently purify pollutants such as sulfur oxides, nitrogen oxides, hydrogen sulfide and the like in the rubber asphalt flue gas.

Description

Catalyst for purifying flue gas of rubber asphalt and preparation method thereof
Technical Field
The invention relates to the technical field of asphalt flue gas purification, in particular to a catalyst for rubber asphalt flue gas purification and a preparation method thereof.
Background
With the rapid development of the traffic industry, the increasing traffic load and traffic volume accelerate the deterioration of asphalt pavement, and the common asphalt pavement cannot meet the current highway grade requirement. The research shows that the rubber powder obtained by crushing the waste tires is added into asphalt, so that the high-temperature stability, the fatigue life and the crack resistance of the asphalt pavement can be improved, and a green mode is provided for the recovery treatment of the waste tires.
Although the rubber asphalt has obvious advantages, compared with the common asphalt, the rubber asphalt can generate more toxic and harmful smoke (such as volatile organic compounds VOCs and hydrogen sulfide H) in the production and mixing process 2 S, sulfur oxides SO x Nitrogen oxides NO x And dust particles, etc.). The release of these fumes not only can adversely affect the respiratory system of the on-site staff, but also can pose a serious threat to the ecological environment. Therefore, the rubber asphalt flue gas must be purified before being discharged to the atmosphere to ensure that the rubber asphalt flue gas meets the environmental protection requirements.
In order to solve the above problems, the prior art proposes the following treatment methods to avoid or reduce the environmental impact of pollutants in flue gas: such as mechanical separation, condensation, filtration, high temperature combustion, low temperature plasma, etc. However, the prior art generally suffers from the following drawbacks: 1) Only has good purifying effect on organic pollutants and dust particles in the flue gas, and cannot effectively purify small molecular pollutants such as hydrogen sulfide, sulfur oxides, nitrogen oxides and the like in the flue gas; 2) When the flue gas purification reaction is carried out, the flue gas is required to be led into different reaction units to be respectively purified, the treatment process is complex, and the time consumption is long; 3) The prepared catalyst for flue gas purification has the advantages of expensive raw materials, high treatment process cost and unfavorable engineering popularization and application.
Therefore, the invention provides a catalyst for purifying rubber asphalt flue gas and a preparation method thereof.
Disclosure of Invention
The invention provides a catalyst for purifying rubber asphalt flue gas and a preparation method thereof, aiming at solving the problems of complex treatment process, long time consumption, high cost of catalytic materials and the like in the prior art.
The invention relates to a catalyst for purifying rubber asphalt flue gas and a preparation method thereof, which are realized by the following technical scheme:
the first object of the invention is to provide a preparation method of a catalyst for purifying flue gas of rubber asphalt, which comprises the following steps:
step 1, taking crop wastes as a carbon source, drying, crushing, and then carbonizing to obtain biochar;
wherein the crop waste is any one of corn straw, wheat straw and bagasse;
step 2, uniformly mixing the biochar with sodium amide, and performing activation treatment to obtain modified biochar;
step 3, uniformly mixing the modified biochar with acid liquor, performing hydrothermal reaction, filtering, washing and drying to obtain a precursor;
step 4, placing the precursor in a metal salt solution, and performing ultrasonic treatment to obtain a mixed solution;
step 5, placing ascorbic acid and gelatin in an aqueous solvent, and regulating the pH to 13.8-14 by using alkali liquor to obtain a reducing agent; and heating the reducing agent to 82-88 ℃, adding the reducing agent into the mixed solution under the stirring action, stirring, filtering, washing and drying to obtain the catalyst for purifying the rubber asphalt flue gas.
Further, the metal salt solution is a cupric ion solution.
Further, the dosage ratio of the metal salt solution to the precursor is 20 mL:0.2-0.5 g;
and the concentration of the metal salt solution is 0.02-0.04 mol/L.
Further, in the reducing agent, the concentration of the ascorbic acid is 0.05-0.2 mol/L, and the mass concentration of the gelatin is 0.1-5%;
and the volume ratio of the reducing agent to the mixed solution is 18-22:1.
Further, the mass ratio of the biochar to the sodium amide is 2-5:1.
Further, the acid liquor is hydrochloric acid or nitric acid;
the dosage ratio of the acid liquor to the modified biochar is 15-25 mL/1 g;
and the concentration of the acid liquor is 0.1-0.5 mol/L.
Further, the carbonization treatment is performed under N 2 Or in Ar atmosphere, the carbonization temperature is 350-750 ℃, and the carbonization time is 0.5-3.5 h.
Further, the activation treatment is performed on N 2 Or in Ar atmosphere, the activation temperature is 300-500 ℃ and the activation time is 1-3 h.
Further, the temperature of the hydrothermal reaction is 70-90 ℃ and the reaction time is 6-12 h.
Further, in the step 4, the ultrasonic frequency of the ultrasonic wave is 35-45 kHz, and the ultrasonic time is 10-30 min.
Further, in the step 5, the stirring speed of the stirring treatment is 300-500 r/min, and the stirring time is 8-16 h.
Further, in the step 1, the drying temperature is 40-70 ℃ and the drying time is 8-24 hours.
Further, in the step 3, the drying temperature is 60-105 ℃ and the drying time is 8-24 hours.
Further, in the step 5, the drying temperature is 20-45 ℃ and the drying time is 8-24 hours.
The second object of the invention is to provide a catalyst for purifying flue gas of rubber asphalt prepared by the preparation method.
Compared with the prior art, the invention has the following beneficial effects:
the 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 bagasse. This not only provides a sufficient carbon source, but also alleviates the problems of environmental pollution and resource waste caused by accumulation of waste crops.
The invention preferably takes the sodium amide as an activator to activate the biochar, wherein the sodium amide not only can further promote the formation of pores in the carbon-based material, but also can reduce the activation temperature, so that the activation of the biochar can be realized at a lower temperature, and the porous carbon-based material is further obtained. And the sodium amide can also introduce nitrogen atoms into the carbon-based material framework in the activation treatment process, so that the nitrogen doping of the carbon-based material can be realized while the activation treatment is carried out, and the nitrogen doped porous carbon-based material is further obtained.
According to the invention, the modified biochar is further modified by acid liquor, so that the pores of the carbon-based material can be further increased, the functional groups (-C-O, C =O, -O-C=O and the like) on the surface of the carbon-based material can be increased, the construction of oxygen-containing groups is further realized on the basis of doping nitrogen atoms in the carbon-based material, and further, the further catalytic purification treatment of nitrogen oxides in the flue gas by the synergistic effect of nitrogen doping and the oxygen-containing functional groups is facilitated.
The method takes the solution containing the bivalent copper ions as the metal salt solution, and adopts the ultrasonic treatment mode to uniformly disperse the precursor in the metal salt solution, so that the precursor is uniformly surrounded by the metal copper ions in the metal salt, and further the precursor is uniformly converted into the metal copper simple substance on the surface of the precursor. And after the metal copper simple substance is loaded, the adsorption capacity of the precursor on sulfur oxide and hydrogen sulfide gas can be further improved, so that the purification effect of asphalt flue gas can be improved.
The invention preferably takes ascorbic acid as a reducing agent, and adds the ascorbic acid into the mixed solution to reduce metallic copper ions into metallic copper simple substance, and the metallic copper simple substance is evenly separated out on the surface of the precursor, thus forming the carbon-based material with nano copper on the surface, namely the catalyst for purifying the rubber asphalt flue gas.
According to the invention, through a step directional construction strategy of doping nitrogen and adding oxygen-containing functional groups, excellent pore structures are obtained, and simultaneously nitrogen atoms and the oxygen-containing functional groups can be made to act synergistically, so that the purification of small molecular pollutants such as sulfur oxides, nitrogen oxides and the like in rubber asphalt flue gas is realized.
The preparation method disclosed by the invention is convenient to operate, low in preparation cost, mild in reaction condition, high in reaction efficiency, capable of relying on the existing mature physical activation process, and good in application prospect and industrialization potential. The catalyst for purifying the rubber asphalt flue gas has larger porosity, specific surface area and active sites, and can quickly and efficiently purify pollutants such as hydrogen sulfide, nitrogen oxides and the like; the catalyst for purifying the rubber asphalt flue gas has high temperature and wear resistance, long service life and capability of being used as a catalyst for purifying the flue gas for a long time.
Drawings
FIG. 1 is a schematic view showing H of the catalyst for flue gas purification for rubber asphalt obtained in examples 1 to 13 and comparative examples 1 to 3 2 S inhibition test results.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below.
The invention provides a catalyst for purifying flue gas of rubber asphalt, and the preparation method thereof is as follows:
step 1, taking crop wastes as a carbon source, drying, crushing, and then carbonizing to obtain biochar;
in the invention, crop waste is preferably used as a carbon source in consideration of the cost of raw materials and the availability of raw materials, and the crop waste can be selected from any one of corn stalk, wheat straw and bagasse. This not only provides a sufficient carbon source, but also alleviates the problems of environmental pollution and resource waste caused by the stacking of crop wastes.
The invention preferably firstly carries out drying treatment on the crop waste to remove redundant moisture, and then screens the crushed crop waste through a 100-mesh sieve to prepare the crop waste particles, so that the crop waste particles can easily form porous carbon-based materials in the carbonization treatment process. Wherein the temperature of the drying treatment is 40-70 ℃ and the drying time is 8-24 h. Carbonization treatment at N 2 Or in Ar atmosphere, the carbonization temperature is 350-750 ℃, and the carbonization time is 0.5-3.5 h.
Step 2, uniformly mixing the biochar with sodium amide, and performing activation treatment to obtain modified biochar;
in the invention, the activated carbon is preferably activated by taking the sodium amide as an activator, wherein the sodium amide not only can further promote the formation of pores in the carbon-based material, but also can reduce the activation temperature, so that the activated carbon can be activated at a lower temperature, and the porous carbon-based material is obtained. And the sodium amide can also introduce nitrogen atoms into the carbon-based material framework in the activation treatment process, so that the nitrogen doping of the carbon-based material is realized at the same time of the activation treatment, and the nitrogen doped porous carbon-based material is further obtained. And the alkalinity of the activated carbon is increased through nitrogen doping, the electronic structure of the surface of the activated carbon is improved, and the chemical activity of the activated carbon is enhanced, so that the adsorption capacity of the activated carbon on acidic pollutants (hydrogen sulfide and the like) is enhanced. In addition, the preferred mass ratio of the biochar to the sodium amide is 2-5:1; and the activation treatment is carried out on N 2 Or in Ar atmosphere, the activation temperature is 300-500 ℃ and the activation time is 1-3 h.
Step 3, uniformly mixing the modified biochar with acid liquor, performing hydrothermal reaction, filtering, washing and drying to obtain a precursor;
the acid liquor adopted in the invention is preferably hydrochloric acid or nitric acid, and the dosage ratio of the acid liquor to the modified biochar is 15-25 mL/1 g; and the concentration of the acid liquor is 0.1-0.5 mol/L. The modified biochar is further modified by acid liquor, so that the pores of the carbon-based material can be further increased, functional groups (-C-O, C =O, -O-C=O and the like) on the surface of the carbon-based material can be increased, the construction of oxygen-containing groups is further realized on the basis of doping nitrogen atoms in the carbon-based material, and further, the further catalytic purification treatment of nitrogen oxides by the carbon-based material is facilitated through the synergistic effect of nitrogen doping and the oxygen-containing functional groups. The temperature of the hydrothermal reaction is 70-90 ℃ and the reaction time is 6-12 h. And the drying temperature is 60-105 ℃ and the drying time is 8-24 h.
Step 4, placing the precursor in a metal salt solution, and performing ultrasonic treatment to obtain a mixed solution;
the solution containing cupric ions is preferably used as the metal salt solution in the present invention, and may be selected from copper nitrate, copper chloride, copper sulfate solution, and the like, preferably copper chloride solution; and the dosage ratio of the metal salt solution to the precursor is 20 mL:0.2-0.5 g; and the concentration of the metal salt solution is 0.02-0.04 mol/L. In addition, the precursor is uniformly dispersed in the metal salt solution by adopting the ultrasonic treatment mode, so that the precursor is uniformly surrounded by the metal copper ions in the metal salt, and further the precursor surface is uniformly converted into the metal copper simple substance by the subsequent metal ions. And after the metal copper simple substance is loaded, the adsorption capacity to hydrogen sulfide can be further improved, and the desulfurization effect is further improved. In order to ensure the effect of ultrasonic treatment, the preferred ultrasonic frequency is 35-45 kHz, and the ultrasonic time is 10-30 min.
Step 5, placing ascorbic acid and gelatin in an aqueous solvent, and regulating the pH to 13.8-14 by using alkali liquor to obtain a reducing agent; heating the reducing agent to 82-88 ℃, adding the reducing agent into the mixed solution under the stirring action, stirring, filtering, washing and drying to obtain the catalyst for purifying the rubber asphalt flue gas;
in the invention, ascorbic acid is preferably used as a reducing agent, and is added into the mixed solution, so that metallic copper ions can be reduced into metallic copper simple substances in an alkaline environment, and the metallic copper simple substances are uniformly separated out on the surface of a precursor, so that a carbon-based material with nano copper on the surface, namely the catalyst for purifying the rubber asphalt flue gas, is formed. In the reducing agent, the concentration of the ascorbic acid is 0.05-0.2 mol/L, and the mass concentration of the gelatin is 0.1-5%; and the volume ratio of the reducing agent to the mixed solution is 1:18-22. In order to ensure the uniformity of reduction, the stirring speed of stirring treatment is 300-500 r/min, and the stirring time is 8-16 h. In the invention, alkali liquor and deionized water are preferably used as detergents for washing treatment until the washing liquid is neutral. Wherein the alkaline solution is selected from sodium hydroxide solution or potassium hydroxide solution. And the drying temperature is 20-45 ℃ and the drying time is 8-24 h.
Example 1
The embodiment provides a catalyst for purifying flue gas of rubber asphalt, and the preparation method thereof is as follows:
step one, preparing biochar
1) Preparation of crop waste particles
The bagasse is taken as a carbon source, is dried in an oven at 60 ℃ for 12 hours, is crushed by a crusher, and passes through a 100-mesh sieve to obtain crop waste particles.
2) Carbonized crop waste particles
And (3) heating the obtained crop waste particles to 500 ℃ in Ar atmosphere, preserving heat for 2 hours, and cooling to room temperature to obtain the biochar.
Modifying the biochar by adopting sodium amide
Mixing the obtained biochar with sodium amide according to the mass ratio of 2.5:1, and grinding for 15min to refine crystal grains and uniformly mix the crystal grains to obtain a mixed material;
and then, carrying out activation treatment on the mixture in Ar atmosphere, heating to 400 ℃, preserving heat for 2 hours, and cooling to room temperature to obtain the modified biochar.
Step three, preparing a precursor
Taking 1g of the prepared modified biochar, placing the modified biochar into 20mL of hydrochloric acid solution with the concentration of 0.2mol/L, stirring the solution for 10min at the stirring rate of 300r/min to uniformly mix the solution, then transferring the solution into a polytetrafluoroethylene lining, loading the polytetrafluoroethylene lining into a kettle, reacting for 8h at the temperature of 80 ℃, cooling the solution to room temperature, filtering the reaction product, alternately washing the reaction product with ethanol and deionized water until the washing solution is neutral, and then drying the reaction product at the temperature of 85 ℃ for 12h to obtain the precursor.
Step four, preparing a catalyst
Grinding the obtained precursor in a mortar for 10min to obtain precursor powder; 0.3g of the precursor powder prepared above was taken, placed in 20mL of a copper chloride solution having a concentration of 0.03mol/L, and subjected to ultrasonic treatment at an ultrasonic frequency of 40kHz for 20 minutes to obtain a mixed solution.
The ascorbic acid and the gelatin are placed in an aqueous solvent to prepare a solution with the concentration of the ascorbic acid being 0.1mol/L and the mass concentration of the gelatin being 2%, and the pH of the solution is regulated to 14 by a sodium hydroxide solution with the concentration of 6mol/L to obtain a reducing agent, and the reducing agent is heated to 86 ℃ for standby.
Stirring the mixed solution at a speed of 400r/min, heating the mixed solution to 80 ℃, and then adding a heated reducing agent into the mixed solution under the heating and stirring effects, wherein the volume ratio of the adding amount of the reducing agent to the mixed solution is 1:20, so as to obtain mixed slurry; continuously stirring and stirring the mixed slurry at the temperature of 85 ℃ at the speed of 400r/min for 12 hours, cooling to room temperature, filtering a reaction product, and alternately washing with ethanol and deionized water until a washing solution is neutral; and then drying for 12 hours at the temperature of 40 ℃ to obtain the catalyst for purifying the rubber asphalt flue gas.
Example 2
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in the embodiment, the mass ratio of the biochar to the sodium amide is 2:1; and the temperature of the activation treatment is 300 ℃ and the activation time is 3 hours.
Example 3
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in the embodiment, the mass ratio of the biochar to the sodium amide is 5:1; and the activation treatment temperature is 500 ℃ and the activation time is 1h.
Example 4
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in the embodiment, the dosage ratio of the acid liquor to the modified biochar is 15mL to 1g; and the concentration of the acid liquor is 0.1mol/L.
Example 5
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in the embodiment, the dosage ratio of the acid liquor to the modified biochar is 25mL to 1g; and the concentration of the acid liquor is 0.5mol/L.
Example 6
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in this example, the ratio of copper chloride solution to precursor was 20mL:0.2g; and the concentration of the metal salt solution is 0.02mol/L.
Example 7
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in this example, the ratio of copper chloride solution to precursor was 20mL:0.5g; and the concentration of the metal salt solution is 0.04mol/L.
Example 8
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in this example, the ultrasonic frequency was 35kHz and the ultrasonic time was 10 minutes.
Example 9
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in this example, the ultrasonic frequency was 45kHz and the ultrasonic time was 30 minutes.
Example 10
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in the embodiment, the concentration of the ascorbic acid in the reducing agent is 0.05mol/L, and the mass concentration of the gelatin is 0.1%; and the volume ratio of the reducing agent to the mixed solution is 1:18.
Example 11
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in the embodiment, the concentration of the ascorbic acid in the reducing agent is 0.2mol/L, and the mass concentration of the gelatin is 5%; and the volume ratio of the reducing agent to the mixed solution is 1:22.
Example 12
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in this embodiment, during the carbonization treatment, corn stalks are used as a carbon source.
Example 13
This example provides a catalyst for flue gas purification of rubber asphalt, and the preparation method thereof differs from example 1 only in that:
in this embodiment, during the carbonization treatment, the wheat straw is used as a carbon source.
Comparative example 1
This comparative example differs from example 1 only in that:
in the comparative example, the activated treatment is carried out without adding sodium amide, and the hydrothermal reaction is directly carried out by using biochar and acid liquor.
Comparative example 2
This comparative example differs from example 1 only in that:
in this comparative example, the modified biochar was directly placed in a metal salt solution without adding an acid solution.
Comparative example 3
This comparative example differs from example 1 only in that:
in the comparative example, no metal salt solution or reducing agent is added, i.e., no nano metal simple substance layer is coated on the surface of the precursor material.
Test section
(1)SO 2 Test of NO removal efficiency
According to the invention, 10g of the rubber asphalt flue gas purifying catalysts prepared in examples 1-13 and comparative examples 1-3 are respectively weighed, placed in a fixed reactor, heated to 120 ℃, and subjected to simulated flue gas test. Wherein, the simulated flue gas composition is: SO (SO) 2 (3％)、NO(2％)、O 2 (10%) and the balance gas is N, the gas flow is 0.5L/min 2 The rubber asphalt smoke purifying catalyst pairs SO prepared in examples 1 to 13 and comparative examples 1 to 3 were tested 2 And NO removal efficiency. The test results are shown in table 1:
TABLE 1SO 2 Test of NO removal efficiency
As is clear 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, SO 2 The removal efficiency is up to 87.5%, and the NO removal efficiency can reach more than 70%. And it is understood from the test results of comparative examples 1 to 13 that the present invention achieves an effective flue gas cleaning effectThe invention is realized by processing a single component or step, and is realized by each component and each step in turn. And it is apparent from the test results of comparative examples 1 and comparative examples 1 to 3 that the modification treatment of biochar by sodium amide has the greatest effect on the efficiency of flue gas purification, the next least effect on acid treatment, and the least effect on metal salts and reducing agents.
(2) Hydrogen sulfide inhibition test
The present invention weighed 10g of the catalysts for purifying rubber asphalt flue gas prepared in examples 1 to 13 and comparative examples 1 to 3, respectively, and conducted H 2 S inhibition rate test, which comprises the following steps: 250g of rubber asphalt was poured into a three-necked flask, and then heated at constant temperature, and the rubber asphalt flue gas purifying catalysts prepared in examples 1 to 13 and comparative examples 1 to 3 were placed in a fixed reactor at the tail of the apparatus. Wherein the heating temperature is 200 ℃, the heating time is 1h, and the carrier gas is N 2 And the test results are shown in fig. 1.
As is clear from FIG. 1, the catalyst for flue gas purification of rubber asphalt prepared in example 1 of the present invention has an optimal hydrogen sulfide inhibition effect, and the inhibition rate is as high as 60% or more at 200 ℃. And as is clear from the test results of comparative examples 1 to 13, the present invention achieves an effective hydrogen sulfide inhibition effect not by a single component or step treatment but by each component and each step being performed sequentially. And it is apparent from the test results of comparative example 1 and comparative examples 1 to 3 that the modification treatment of biochar by sodium amide has the greatest effect on the hydrogen sulfide inhibition effect, the next least effect on the acid treatment, and the least effect on the metal salt and the reducing agent.
It should be apparent that the embodiments described above are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Claims (10)

1. The preparation method of the catalyst for purifying the rubber asphalt flue gas is characterized by comprising the following steps of:
step 1, taking crop wastes as a carbon source, drying, crushing, and then carbonizing to obtain biochar;
wherein the crop waste is any one of corn straw, wheat straw and bagasse;
step 2, uniformly mixing the biochar with sodium amide, and performing activation treatment to obtain modified biochar;
step 3, uniformly mixing the modified biochar with acid liquor, performing hydrothermal reaction, filtering, washing and drying to obtain a precursor;
step 4, placing the precursor in a metal salt solution, and performing ultrasonic treatment to obtain a mixed solution;
step 5, placing ascorbic acid and gelatin in an aqueous solvent, and regulating the pH to 13.8-14 by using alkali liquor to obtain a reducing agent; and heating the reducing agent to 82-88 ℃, adding the reducing agent into the mixed solution under the stirring action, stirring, filtering, washing and drying to obtain the catalyst for purifying the rubber asphalt flue gas.
2. The method of claim 1, wherein the metal salt solution is a cupric ion solution;
the dosage ratio of the metal salt solution to the precursor is 20 mL:0.2-0.5 g;
and the concentration of the metal salt solution is 0.02-0.04 mol/L.
3. The preparation method according to claim 1, wherein the concentration of ascorbic acid in the reducing agent is 0.05-0.2 mol/L, and the mass concentration of gelatin is 0.1% -5%;
and the volume ratio of the reducing agent to the mixed solution is 1:18-22.
4. The method according to claim 1, wherein the mass ratio of the biochar to the sodium amide is 2-5:1.
5. The method of claim 1, wherein the acid solution is hydrochloric acid or nitric acid;
the dosage ratio of the acid liquor to the modified biochar is 15-25 mL/1 g;
and the concentration of the acid liquor is 0.1-0.5 mol/L.
6. The method of claim 1, wherein the carbonization treatment is performed in N 2 Or in Ar atmosphere, the carbonization temperature is 350-750 ℃, and the carbonization time is 0.5-3.5 h.
7. The method of claim 1, wherein the activation treatment is performed on N 2 Or in Ar atmosphere, the activation temperature is 300-500 ℃ and the activation time is 1-3 h.
8. The preparation method according to claim 1, wherein the hydrothermal reaction is carried out at a temperature of 70 to 90 ℃ for a reaction time of 6 to 12 hours.
9. The preparation method of claim 1, wherein in step 4, the ultrasonic frequency of the ultrasonic wave is 35-45 kHz, and the ultrasonic time is 10-30 min;
in the step 5, the temperature of the stirring treatment is 80-85 ℃, the stirring speed is 300-500 r/min, and the stirring time is 8-16 h.
10. A catalyst for flue gas purification of rubber asphalt prepared by the preparation method of any one of claims 1 to 9.
CN202310632880.3A 2023-05-31 2023-05-31 Catalyst for purifying flue gas of rubber asphalt and preparation method thereof Pending CN116673028A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117101675A (en) * 2023-10-17 2023-11-24 中国农业科学院农业环境与可持续发展研究所 High-entropy alloy modified nitrogen-doped biochar as well as preparation method and application thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117101675A (en) * 2023-10-17 2023-11-24 中国农业科学院农业环境与可持续发展研究所 High-entropy alloy modified nitrogen-doped biochar as well as preparation method and application thereof
CN117101675B (en) * 2023-10-17 2024-02-09 中国农业科学院农业环境与可持续发展研究所 High-entropy alloy modified nitrogen-doped biochar as well as preparation method and application thereof

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