Preparation process of chemical waste gas adsorbent

Abstract

The invention relates to the technical field of waste gas purification, in particular to a preparation process of a chemical waste gas adsorbent. According to the invention, macromolecular substances capable of adsorbing industrial waste gas are chemically grafted on the surface of an inorganic porous material, and other functional treatment steps are combined, so that the chemical waste gas adsorbent with high adsorption capacity, high selectivity, good stability and renewability is prepared, and efficient adsorption and removal of various pollutants in the chemical waste gas are realized; the technical defects of an existing adsorbent are effectively overcome, the chemical waste gas treatment efficiency and quality are improved, and environmental pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas purification, in particular to a preparation process of a chemical waste gas adsorbent. Background Art

[0002] The chemical industry produces a large amount of waste gas with a complex composition during production, including volatile organic compounds (VOCs), acidic gases (such as sulfur dioxide and nitrogen oxides), alkaline gases (such as ammonia), and gaseous pollutants containing heavy metals. If these waste gases are directly discharged into the atmosphere without effective treatment, they will cause serious environmental pollution, leading to environmental problems such as smog and acid rain. They will also pose a serious threat to human health, potentially causing respiratory diseases, cardiovascular diseases, and even cancer. At present, adsorption is one of the commonly used methods for treating chemical waste gas, and its core lies in the performance of the adsorbent. Traditional adsorbents such as activated carbon, silica gel, etc., although they have certain adsorption capacity, have many limitations. Activated carbon has poor adsorption selectivity for different pollutants, making it difficult to efficiently and effectively remove specific waste gas components; the adsorption performance of silica gel is greatly affected by the ambient humidity, and the adsorption efficiency drops significantly in a high humidity environment. In recent years, researchers have tried to improve the performance of adsorption materials by modifying them. Among them, chemical grafting technology, as an effective modification method, can introduce groups or macromolecules with specific functions on the surface of the material, giving the material new adsorption properties. However, the chemical waste gas adsorbents prepared by existing chemical grafting technology still have deficiencies in adsorption efficiency, selectivity, stability, and the ability to synergistically treat multiple pollutants, and cannot meet increasingly stringent environmental protection requirements. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation process for a chemical waste gas adsorbent. By chemically grafting the surface of an inorganic porous material to adsorb macromolecular substances in industrial waste gas, and combining other functional treatment steps, a chemical waste gas adsorbent with high adsorption capacity, high selectivity, good stability and renewability is prepared, thereby achieving efficient adsorption and removal of various pollutants in chemical waste gas, effectively filling the technical defects of existing adsorbents, improving the efficiency and quality of chemical waste gas treatment, and reducing environmental pollution.

[0004] To achieve the above object, the present invention provides the following technical solutions: A preparation process for a chemical waste gas adsorbent comprises the following steps: Step 1: Under the protection of nitrogen, 0.85 to 0.9 times the volume of methyl acrylate and 1.5 to 2.5 times the volume of diethylenetriamine are slowly added dropwise to diethylenetriamine in an ice-water bath environment, the mixture is stirred evenly, and the mixture is reacted at room temperature for 4 to 6 hours. After the reaction is completed, the residual solvent in the product is recovered by vacuum distillation, and the obtained reaction monomer is stored for future use; Step 2: Add the amino activated carbon and the amino composite substrate into a reaction monomer 8 to 15 times the mass of the amino activated carbon and the amino composite substrate respectively, mix them, react at a temperature of 65 to 75° C. for 2 to 3 hours, and then heat them to 80 to 95° C. for 3 to 5 hours; filter the reaction products, wash them with methanol 4 to 5 times, and vacuum dry them to obtain modified activated carbon and modified composite substrate respectively; wherein the composite substrate is graphene oxide loaded with nano-titanium dioxide; Step 3: After the modified activated carbon is activated twice, it is put into a mixing device together with 6-10% of nano-cerium oxide and 15-20% of the modified composite substrate by mass, and the chemical waste gas adsorbent is obtained after mixing.

[0005] Furthermore, the preparation method of the amino composite substrate is: 3-aminopropyltrimethoxysilane is uniformly dispersed in an ethanol aqueous solution with a volume concentration of 85-90% at a dosage ratio of 0.1-0.2 g / mL, the pH is adjusted to 3.6-4.2 with formic acid, and a composite substrate with a mass 3-5 times that of 3-aminopropyltrimethoxysilane is added, and the reaction is stirred at a temperature of 50-60°C for 5-8 hours; after the reaction is completed, the reaction product is filtered, washed with water and dried in sequence.

[0006] Furthermore, the activated carbon is selected from any one of coconut shell activated carbon and apricot kernel shell activated carbon, and its particle size is 2 to 4 mm.

[0007] Furthermore, the preparation method of the composite substrate is: acetic acid, anhydrous ethanol and tetrabutyl titanate are mixed and stirred in a volume ratio of 0.15-0.25:1:4-6 for 40-60 minutes, and then an aqueous dispersion of graphene oxide is added to the resulting colloid, and stirred at a rate of 300-500 r / min for 80-150 minutes; the resulting mixed components are transferred to a microwave reactor, treated at a power of 500 W for 50-80 minutes, and then dried and sintered to obtain a composite substrate; wherein the concentration of graphene oxide in the aqueous dispersion of graphene oxide is 30-60 g / L, and the amount of graphene oxide used is 5-8% of the mass of the colloid.

[0008] Furthermore, the drying temperature is 100-120° C., and the drying time is 100-150 minutes.

[0009] Furthermore, the sintering temperature is set to 400-480° C., and the sintering time is set to 2-3 hours.

[0010] Furthermore, the preparation method of the amino activated carbon is as follows: ultrasonically dispersing the pretreated activated carbon in thionyl chloride with a mass of 6 to 10 times that of the pretreated activated carbon, refluxing the reaction for 2 to 3 hours, and then distilling the excess thionyl chloride under reduced pressure to recover the excess thionyl chloride, adding N,N-dimethylformamide with a mass of 4 to 6 times that of thionyl chloride to the remaining components after distillation, and dripping triethylamine with a mass of 10 to 15 times that of the pretreated activated carbon and triethylenetetramine with a mass of 1.5 to 2 times that of the pretreated activated carbon under ice-water bath conditions, stirring the reaction for 3 to 5 hours, and then filtering the resultant components, washing the filter cake alternately with ethanol and deionized water until the washing liquid is neutral, and then drying the filter cake.

[0011] Furthermore, the preparation method of the pretreated activated carbon is: immersing the cleaned and dried activated carbon in a 5-10wt% potassium permanganate solution, adjusting the pH to 3.5-4 with dilute sulfuric acid, and heat-treating at a temperature of 30-40°C for 10-15 hours; then performing solid-liquid separation, water washing and drying to obtain the pretreated activated carbon.

[0012] Furthermore, the specific steps of the first activation are: by weight, 40 to 50 parts of amino activated carbon, 1.5 to 2.5 parts of tetrahydroxymethylmethane, 0.5 to 0.8 parts of tannic acid, 0.1 to 0.3 parts of citric acid, 0.2 to 0.4 parts of xanthophylls, 3 to 5 parts of ethyl acetate, and 50 to 75 parts of an ethanol aqueous solution with a volume concentration of 20 to 40% are mixed, and heat-treated at a temperature of 40 to 50° C. for 2 to 4 hours; and then evaporated and dehydrated.

[0013] Furthermore, the specific steps of the secondary activation are: mixing the activated material obtained after the first activation with 4-6% ammonium molybdate and 8-12% sodium tripolyphosphate by mass of amino activated carbon, and heat treating it at a temperature of 120-140°C for 25-35 minutes under the protection of nitrogen.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention uses tetrabutyl titanate and graphene oxide as raw materials to prepare nano-titanium dioxide-loaded graphene oxide, a composite substrate. The surface of graphene oxide is rich in oxygen-containing functional groups such as hydroxyl, carboxyl, and epoxy groups, which can adsorb polar molecules and aromatic compounds through hydrogen bonding, electrostatic interactions, or π-π stacking. Nano-titanium dioxide exhibits photocatalytic activity. Under ultraviolet light excitation, electron-hole pairs are generated, generating hydroxyl radicals and superoxide radicals, which can oxidatively degrade pollutants in industrial waste gas. Furthermore, graphene oxide and nano-titanium dioxide combine through π-π conjugation, electrostatic interactions, or chemical bonds (such as Ti-OC bonds), forming an integrated "adsorption-catalysis" system. Graphene oxide improves the dispersibility of nano-titanium dioxide and inhibits its aggregation. Simultaneously, as an electron acceptor, it accelerates charge separation, enhancing photocatalytic efficiency. Nano-titanium dioxide photocatalytically degrades pollutants adsorbed by the graphene oxide, preventing saturation of adsorption sites and achieving efficient adsorption and purification of pollutants and contaminated gases in industrial waste gas.

[0015] 2. The present invention pre-treats activated carbon with potassium permanganate, introducing a high number of highly polar oxygen-containing functional groups (such as hydroxyl and carboxyl groups) onto the surface of the activated carbon. The pre-treated activated carbon is then subjected to an amination treatment, paving the way for subsequent grafting of a hyperbranched polymer. The amination-treated composite substrate and the amination-treated activated carbon are then separately introduced into a reaction monomer, which undergoes an amidation reaction with the relevant active groups on their surfaces, ultimately grafting the hyperbranched polymer onto their surfaces and interiors. The presence of the hyperbranched polymer creates a dense, three-dimensional envelope on the surfaces and interiors of the modified activated carbon and the modified composite substrate, significantly enhancing the physical adsorption performance of the adsorbent. Furthermore, due to the high density of amino groups on the molecular chain of the hyperbranched polymer, the prepared adsorbent can not only have a good adsorption effect on acidic gases (such as SO2, CO2 and NOx), halogenated hydrocarbons and polar VOCs (such as formaldehyde and acetone) in the exhaust gas, but also can combine with metal ions through coordination to form stable chelates, thereby achieving the effect of adsorbing heavy metals (Hg, Cd, Pb and other metal vapors or compounds).

[0016] 3. During the initial activation of the modified activated carbon, the polyhydroxyl groups of tetramethylolmethane react with amino groups on the modified activated carbon surface through hydrogen bonding or condensation reactions to form a three-dimensional network structure, increasing adsorption sites. Tannic acid (containing phenolic hydroxyl groups) and xanthophylls (containing conjugated double bonds) adhere to the modified activated carbon surface through π-π stacking and polar interactions, enhancing their affinity for polar VOCs (such as formaldehyde) and aromatic compounds (such as toluene). Ethyl acetate, used as a solvent, promotes uniform dispersion. After evaporation, it optimizes the pore structure and increases physical adsorption capacity.

[0017] During the secondary activation process, ammonium molybdate decomposes at high temperature to generate MoO3, which is loaded on the surface of modified activated carbon and catalyzes the oxidation of SO2 and NO. xThe modified composite substrate synergistically enhances the photocatalytic degradation of VOCs. DETAILED DESCRIPTION

[0018] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 any creative efforts shall fall within the scope of protection of the present invention. Example 1

[0019] A preparation process for a chemical waste gas adsorbent comprises the following steps: Step 1: Under the protection of nitrogen, 0.85 times the volume of methyl acrylate and 1.5 times the volume of methanol were slowly added dropwise to diethylenetriamine in an ice-water bath environment, mixed and stirred evenly, and reacted at room temperature for 4 hours. After the reaction was completed, the residual solvent in the product was recovered by vacuum distillation, and the obtained reaction monomer was stored for future use; Step 2: Add the amino activated carbon and the amino composite substrate into a reaction monomer 8 times the mass of the amino activated carbon and the amino composite substrate respectively, mix them, react at 65°C for 3 hours, and then heat them to 80°C for 5 hours; filter the reaction products, wash them with methanol 4 times, and vacuum dry them to obtain modified activated carbon and modified composite substrate respectively; wherein the composite substrate is graphene oxide loaded with nano-titanium dioxide; Step 3: After the modified activated carbon is activated twice, it is put into a mixing device together with 6% of nano-cerium oxide and 15% of the modified composite substrate by weight, and the chemical waste gas adsorbent is obtained after mixing.

[0020] The preparation method of the amino-containing composite substrate is as follows: 3-aminopropyltrimethoxysilane is uniformly dispersed in an ethanol aqueous solution with a volume concentration of 85% at a dosage ratio of 0.1 g / mL, the pH is adjusted to 3.6 with formic acid, and then a composite substrate with a mass three times that of 3-aminopropyltrimethoxysilane is added, and the reaction is stirred at a temperature of 50°C for 8 hours; after the reaction is completed, the reaction product is filtered, washed with water and dried in sequence.

[0021] The activated carbon is coconut shell activated carbon with a particle size of 2 mm.

[0022] The preparation method of the composite substrate is as follows: acetic acid, anhydrous ethanol and tetrabutyl titanate are mixed and stirred at a volume ratio of 0.15:1:4 for 40 minutes, then a graphene oxide aqueous dispersion is added to the obtained colloid, and stirred at a rate of 300 r / min for 150 minutes; the obtained mixed components are transferred to a microwave reactor, treated at a power of 500 W for 50 minutes, and then dried and sintered to obtain a composite substrate; wherein the concentration of graphene oxide in the graphene oxide aqueous dispersion is 30 g / L, and the amount of graphene oxide is 5% of the mass of the colloid; the drying temperature is 100°C, and the drying time is 150 minutes; the sintering temperature is set to 400°C, and the sintering time is set to 3 hours.

[0023] The preparation method of amino activated carbon is as follows: ultrasonically disperse the pretreated activated carbon in thionyl chloride with a mass 6 times that of the pretreated activated carbon, reflux the reaction for 2 hours, and then distill under reduced pressure to recover excess thionyl chloride, add N,N-dimethylformamide with a mass 4 times that of thionyl chloride to the remaining components after distillation, and dropwise add triethylamine with a mass 10 times that of the pretreated activated carbon and triethylenetetramine with a mass 1.5 times that of the pretreated activated carbon under ice-water bath conditions, stir and react for 3 hours, then filter the resultant components, wash the filter cake alternately with ethanol and deionized water until the washing liquid is neutral, and then dry it.

[0024] The preparation method of pretreated activated carbon is as follows: immersing the cleaned and dried activated carbon in a 5wt% potassium permanganate solution, adjusting the pH to 3.5 with dilute sulfuric acid, and heat-treating at 30°C for 15 hours; then performing solid-liquid separation, water washing and drying to obtain the pretreated activated carbon.

[0025] The specific steps of the first activation are: by weight, 40 parts of amino activated carbon, 1.5 parts of tetrahydroxymethylmethane, 0.5 parts of tannic acid, 0.1 parts of citric acid, 0.2 parts of xanthophylls, 3 parts of ethyl acetate, and 50 parts of 20% ethanol aqueous solution are mixed, and heat-treated at 40°C for 3 hours; then evaporated and dehydrated.

[0026] The specific steps of the secondary activation are: mixing the activated material obtained after the first activation with 4% ammonium molybdate and 8% sodium tripolyphosphate of amino activated carbon respectively, and heat treating at 120°C for 35 minutes under the protection of nitrogen. Example 2

[0027] A preparation process for a chemical waste gas adsorbent comprises the following steps: Step 1: Under the protection of nitrogen, 0.9 times the volume of methyl acrylate and 2 times the volume of methanol were slowly added dropwise to diethylenetriamine in an ice-water bath environment, mixed and stirred evenly, and reacted at room temperature for 5 hours. After the reaction was completed, the residual solvent in the product was recovered by vacuum distillation, and the obtained reaction monomer was stored for future use; Step 2: Add the amino activated carbon and the amino composite substrate into a reaction monomer 10 times the mass of the amino activated carbon and the amino composite substrate respectively, mix them, react at 70°C for 3 hours, and then heat them to 85°C for 4 hours; filter the reaction products, wash them with methanol 5 times, and vacuum dry them to obtain modified activated carbon and modified composite substrate respectively; wherein the composite substrate is graphene oxide loaded with nano-titanium dioxide; Step 3: After the modified activated carbon is activated twice, it is put into a mixing device together with 8% by mass of nano-cerium oxide and 15% by mass of the modified composite substrate, and the chemical waste gas adsorbent is obtained after mixing.

[0028] The aminated composite substrate, composite substrate, aminated activated carbon, preparation method of pretreated activated carbon, modified activated carbon through two activation steps, and selection of activated carbon in this embodiment are the same as those in Example 1. Example 3

[0029] A preparation process for a chemical waste gas adsorbent comprises the following steps: Step 1: Under the protection of nitrogen, 0.9 times the volume of methyl acrylate and 2.5 times the volume of methanol were slowly added dropwise to diethylenetriamine in an ice-water bath environment, mixed and stirred evenly, and reacted at room temperature for 6 hours. After the reaction was completed, the residual solvent in the product was recovered by vacuum distillation, and the obtained reaction monomer was stored for future use; Step 2: Add the amino activated carbon and the amino composite substrate into a reaction monomer 15 times the mass of the amino activated carbon and the amino composite substrate respectively, mix them, react at 75°C for 2 hours, and then heat them to 95°C for 3 hours; filter the reaction products, wash them with methanol 5 times, and vacuum dry them to obtain modified activated carbon and modified composite substrate respectively; wherein the composite substrate is graphene oxide loaded with nano-titanium dioxide; Step 3: After the modified activated carbon is activated twice, it is put into a mixing device together with 10% of nano-cerium oxide and 20% of the modified composite substrate by mass, and the chemical waste gas adsorbent is obtained after mixing.

[0030] The aminated composite substrate, composite substrate, aminated activated carbon, preparation method of pretreated activated carbon, modified activated carbon through two activation steps, and selection of activated carbon in this embodiment are the same as those in Example 1.

[0031] Comparative Example 1: The difference between this comparative example and the embodiment is that in this comparative example, a composite substrate is used to replace an equal amount of modified composite substrate.

[0032] Comparative Example 2: The difference between this comparative example and the embodiment is that in this comparative example, graphene oxide is used to replace an equal amount of the composite substrate.

[0033] Comparative Example 3: The difference between this comparative example and the embodiment is that in this comparative example, nano-titanium dioxide is used to replace an equal amount of the composite substrate.

[0034] Comparative Example 4: The difference between this comparative example and the embodiment is that activated carbon is used in this comparative example instead of an equal amount of modified activated carbon.

[0035] Comparative Example 5: The difference between this comparative example and the embodiment is that the modified activated carbon is not activated for the first time in this comparative example.

[0036] Comparative Example 6: The difference between this comparative example and the embodiment is that in this comparative example, the modified activated carbon is not subjected to secondary activation.

[0037] Adsorption performance test methods and data 1. Testing standards and methods 1. Adsorption capacity and penetration time (GB / T35239-2017) Apparatus: 10mm inner diameter glass adsorption column, constant temperature 25℃ step: (a) Filled with 0.5 g of adsorbent; (b) introducing simulated exhaust gas (benzene: 500 ppm, SO2: 300 ppm, formaldehyde: 200 ppm, flow rate 0.5 L / min); (c) Gas chromatography (GC-FID) monitors the outlet concentration and records the breakthrough time (when the outlet concentration reaches 5% of the inlet concentration); (d) Calculation of adsorption capacity:

[0038] in, m: adsorbent mass (unit: g) C0: inlet concentration (unit: ppm) C t : Outlet concentration (5% C0 at penetration, unit: ppm) V: Gas flow rate (L / min) t: penetration time (min) 2. Heavy metal removal rate (EPAMethod29) step: (a) Introducing exhaust gas containing Hg vapor (50 μg / m³), Cd compounds (30 μg / m³), and Pb vapor (40 μg / m³); (b) ICP-MS determination of inlet and outlet concentrations; (c) Calculation of removal rate: (C0 is the inlet concentration, C t is the outlet concentration).

[0039] 3. Regeneration performance step: (a) Nitrogen desorption at 120 °C for 2 h (flow rate 1 L / min); (b) Repeat the adsorption-desorption cycle 5 times; (c) Calculation of capacity retention rate: .

[0040] 2. Adsorption performance data of each group of adsorbents

[0041] By comparing and analyzing the relevant data in the table, it can be seen that the present invention, through chemical grafting on the surface of an inorganic porous material to adsorb macromolecular substances in industrial waste gas, combined with other functional processing steps, prepares a chemical waste gas adsorbent with high adsorption capacity, high selectivity, good stability and renewability. This achieves efficient adsorption and removal of multiple pollutants in chemical waste gas, effectively filling the technical defects of existing adsorbents, improving the efficiency and quality of chemical waste gas treatment, and reducing environmental pollution. This shows that the preparation process of the chemical waste gas adsorbent provided by the present invention has a broader market prospect and is more suitable for promotion.

[0042] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0043] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A preparation process for a chemical waste gas adsorbent, characterized in that: The following steps are involved: Step 1: Under the protection of nitrogen, 0.85 to 0.9 times the volume of methyl acrylate and 1.5 to 2.5 times the volume of diethylenetriamine are slowly added dropwise to diethylenetriamine in an ice-water bath environment, the mixture is stirred evenly, and the mixture is reacted at room temperature for 4 to 6 hours. After the reaction is completed, the residual solvent in the product is recovered by vacuum distillation, and the obtained reaction monomer is stored for future use; Step 2: Add the amino activated carbon and the amino composite substrate into a reaction monomer 8 to 15 times the mass of the amino activated carbon and the amino composite substrate respectively, mix them, react at a temperature of 65 to 75° C. for 2 to 3 hours, and then heat them to 80 to 95° C. for 3 to 5 hours; filter the reaction products, wash them with methanol 4 to 5 times, and vacuum dry them to obtain modified activated carbon and modified composite substrate respectively; wherein the composite substrate is graphene oxide loaded with nano-titanium dioxide; Step 3: After the modified activated carbon is activated twice, it is put into a mixing device together with 6-10% of nano-cerium oxide and 15-20% of the modified composite substrate by mass, and the chemical waste gas adsorbent is obtained after mixing.

2. The preparation process of a chemical waste gas adsorbent according to claim 1, characterized in that: The preparation method of the amino-containing composite substrate is as follows: 3-aminopropyltrimethoxysilane is uniformly dispersed in an ethanol aqueous solution with a volume concentration of 85-90% at a dosage ratio of 0.1-0.2 g / mL, the pH is adjusted to 3.6-4.2 with formic acid, and then the composite substrate is added with a mass 3-5 times that of 3-aminopropyltrimethoxysilane, and the mixture is stirred and reacted at a temperature of 50-60°C for 5-8 hours; after the reaction is completed, the reaction product is filtered, washed with water, and dried.

3. The preparation process of a chemical waste gas adsorbent according to claim 1, characterized in that: The activated carbon is selected from any one of coconut shell activated carbon and apricot kernel shell activated carbon, and its particle size is 2-4 mm.

4. The preparation process of a chemical waste gas adsorbent according to claim 1 or 2, characterized in that: The preparation method of the composite substrate comprises: mixing acetic acid, anhydrous ethanol and tetrabutyl titanate in a volume ratio of 0.15-0.25:1:4-6 and stirring for 40-60 minutes; then adding graphene oxide aqueous dispersion to the obtained colloid and stirring at a rate of 300-500 r / min for 80-150 minutes; transferring the obtained mixed components into a microwave reactor, treating them at a power of 500 W for 50-80 minutes, and then drying and sintering to obtain the composite substrate; wherein the concentration of graphene oxide in the graphene oxide aqueous dispersion is 30-60 g / L, and the amount of graphene oxide used is 5-8% of the mass of the colloid.

5. The preparation process of a chemical waste gas adsorbent according to claim 4, characterized in that: The drying temperature is 100-120° C., and the drying time is 100-150 minutes.

6. The preparation process of a chemical waste gas adsorbent according to claim 4, characterized in that: The sintering temperature is set to 400-480° C., and the sintering time is set to 2-3 hours.

7. The preparation process of a chemical waste gas adsorbent according to claim 1, characterized in that: The preparation method of the amino activated carbon comprises the following steps: ultrasonically dispersing the pretreated activated carbon in thionyl chloride with a mass of 6 to 10 times that of the pretreated activated carbon, performing a reflux reaction for 2 to 3 hours, and then performing a reduced pressure distillation to recover excess thionyl chloride; adding N,N-dimethylformamide with a mass of 4 to 6 times that of the thionyl chloride to the remaining components after the distillation; and dropwise adding triethylamine with a mass of 10 to 15 times that of the pretreated activated carbon and triethylenetetramine with a mass of 1.5 to 2 times that of the pretreated activated carbon in an ice-water bath; stirring and reacting for 3 to 5 hours, and then filtering the resultant components; washing the filter cake alternately with ethanol and deionized water until the washing liquid is neutral; and then drying the filter cake.

8. The preparation process of a chemical waste gas adsorbent according to claim 7, characterized in that: The preparation method of the pretreated activated carbon comprises the following steps: immersing the cleaned and dried activated carbon in a 5-10wt% potassium permanganate solution, adjusting the pH to 3.5-4 with dilute sulfuric acid, and heat-treating the solution at a temperature of 30-40°C for 10-15 hours; and then performing solid-liquid separation, water washing, and drying to obtain the pretreated activated carbon.

9. The preparation process of a chemical waste gas adsorbent according to claim 1, characterized in that: In step three, the specific steps of the first activation are: by weight, 40 to 50 parts of amino activated carbon, 1.5 to 2.5 parts of tetrahydroxymethylmethane, 0.5 to 0.8 parts of tannic acid, 0.1 to 0.3 parts of citric acid, 0.2 to 0.4 parts of xanthophylls, 3 to 5 parts of ethyl acetate, and 50 to 75 parts of an ethanol aqueous solution with a volume concentration of 20 to 40% are mixed, and heat treated at a temperature of 40 to 50° C. for 2 to 4 hours; and then evaporated and dehydrated.

10. The preparation process of a chemical waste gas adsorbent according to claim 1, characterized in that: In step three, the specific steps of the secondary activation are: mixing the activated material obtained after the first activation with 4-6% ammonium molybdate and 8-12% sodium tripolyphosphate by mass of amino activated carbon, and heat treating it at a temperature of 120-140°C for 25-35 minutes under the protection of nitrogen.

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