Activated carbon-molecular sieve composite material as well as preparation method and application thereof

Abstract

The invention relates to the field of carbon dioxide adsorption materials, and provides an activated carbon-molecular sieve composite material and a preparation method and application thereof, the method is simple in process and low in cost, and the provided composite material can give consideration to good mechanical strength, carbon dioxide adsorption performance and water resistance. The preparation method comprises the following steps: (1) dissolving a binder with water, wherein the binder is selected from one or more of carboxymethyl cellulose, carboxyethyl cellulose and phenolic resin; (2) adding molecular sieve powder into the solution obtained in the step (1), and carrying out ultrasonic dispersion to obtain an emulsion; (3) mixing and stirring the emulsion and activated carbon powder to form pug; (4) pugging the pug, and then standing and aging; and (5) molding and drying the pug obtained in the step (4), and then heating and carbonizing.

Description

Technical Field

[0001] The invention relates to the field of carbon dioxide adsorption materials, and in particular to an activated carbon-molecular sieve composite material and a preparation method and application thereof. Background Art

[0002] Chinese patent CN116726879A discloses a zeolite activated carbon composite material. The raw materials for preparation include modified activated carbon and zeolite, wherein the modified activated carbon is a quaternary ammonium salt located on the surface of the activated carbon for modification, and the zeolite is located on the surface of the modified activated carbon. When the quaternary ammonium salt changes the surface charge of the activated carbon to be positively charged, it can generate electrostatic attraction with the zeolite and thus combine to achieve the preparation of the zeolite activated carbon composite material.

[0003] Chinese patent CN102744095B discloses a zeolite-activated carbon-attapulgite composite carrier flue gas denitration catalyst. The preparation process is to first crush and carbonize rice husk to obtain activated carbon, then add NaOH solution and NaAlO2 solution, and then treat it in a stainless steel reactor at 80-90°C under high pressure to obtain zeolite-activated carbon, then add attapulgite and water to stir, extrude, dry and calcine to obtain a zeolite-activated carbon-attapulgite composite material. This material helps to improve the air permeability of attapulgite and improve the catalyst's adsorption and denitration rate of gas.

[0004] Chinese patent CN102744095B discloses a zeolite-activated carbon-attapulgite composite carrier flue gas denitration catalyst. The use of NaOH lye in the preparation process poses a great safety risk, and the cost will be greatly increased due to the lye treatment. In addition, the use of a stainless steel reactor with a polytetrafluoroethylene lining in the preparation process of the zeolite-activated carbon material is a preparation method for a small number of laboratory studies, which is difficult to scale up industrially, thus restricting its prospects for industrial application and having low practical value.

[0005] Chinese patent CN116726879A discloses a zeolite activated carbon composite material. It is required that the isoelectric point of the modified activated carbon is ≥7 and the mass content of the quaternary ammonium salt in the modified activated carbon is 1-5%; the silicon-aluminum ratio of the zeolite is ≤30 and the mass fraction of the zeolite in the zeolite activated carbon composite material is ≥15%. The above requirements lead to restrictions on the types of quaternary ammonium salts and zeolites during the preparation process, making it impossible to promote this method on a large scale.

[0006] How to develop a carbon dioxide adsorption material with simple preparation process, low cost and good performance is still one of the technical problems that urgently needs to be broken through in this field. Summary of the invention

[0007] The present invention provides an activated carbon - molecular sieve composite material, a preparation method thereof and an application. The method of the present invention has a simple process and low cost, and the provided composite material can take into account good mechanical strength, carbon dioxide adsorption performance and water resistance.

[0008] To achieve its purpose, the present invention provides the following technical solutions:

[0009] The present invention provides a preparation method of an activated carbon - molecular sieve composite material, comprising the following steps:

[0010] (1) Dissolve the binder in water, for example, to obtain a colorless and transparent solution. The binder is selected from one or more of carboxymethyl cellulose, carboxyethyl cellulose, and phenolic resin;

[0011] (2) Add the molecular sieve powder to the solution obtained in step (1) and perform ultrasonic dispersion to obtain an emulsion, for example, a white emulsion;

[0012] (3) Mix and stir the emulsion and activated carbon powder to form a mud material, for example, a viscous mud block;

[0013] (4) Knead the mud material, and then let it stand and age;

[0014] (5) Shape and dry the mud material obtained in step (4), and then heat and carbonize it; In some examples, after heating and carbonizing, it is taken out after natural cooling and cut into the required shape, for example, cylindrical;

[0015] Wherein, the dosage of the binder is 10 - 20% of the mass of the activated carbon, for example, 10%, 12%, 14%, 16%, 18% or 20%, etc.; the dosage of the molecular sieve is 5 - 30% of the mass of the activated carbon, for example, 5%, 10%, 15%, 20%, 25% or 30%, etc.; the dosage of water is 0.8 - 1.2 times the total mass of the binder, the molecular sieve and the activated carbon, for example, 0.8, 1.0, 1.1 or 1.2 times, etc.

[0016] In the present invention, each component is combined in a specific dosage and the activated carbon - molecular sieve composite material is prepared in a specific order. First, the binder is dissolved, then the molecular sieve is dispersed in the binder solution, and then mixed and dispersed with the activated carbon powder. Finally, the obtained composite material can take into account good mechanical strength and carbon dioxide adsorption capacity, has a low powdering rate, and has good water resistance. The preparation method provided by the present invention has a simple process, does not need to introduce other components such as acids and bases, does not produce waste liquids such as acids and bases, and the obtained composite material is particularly suitable for the adsorption and separation of carbon dioxide in wet flue gas.

[0017] By adopting the formulation system and preparation process of the present invention, a composite material with good mechanical strength, carbon dioxide adsorption performance and water resistance can be obtained with a relatively small amount of molecular sieve (not exceeding 30%), and at the same time, the cost increase caused by the high price of the molecular sieve can be reduced. In a preferred embodiment, the mass of the molecular sieve is 8-24% of the mass of the activated carbon. By using the preferred amount of the molecular sieve, it is beneficial to further improve the mechanical properties and carbon dioxide adsorption performance of the composite material.

[0018] In the preparation method of the present invention, the amount of the binder is 10-20% of the mass of the activated carbon. The inventors have found that in the preparation system of the present invention, controlling the amount of the binder to 10-20% of the mass of the activated carbon is beneficial to achieving better structural strength and carbon dioxide adsorption performance compared with lower or higher amounts. In a preferred embodiment, the binder is selected from carboxymethyl cellulose. During the carbonization process, carboxymethyl cellulose will form part of the activated carbon as a carbon source. The inventors have found that in the preparation process of the present invention, using carboxymethyl cellulose compared with other binders is beneficial to further improving the mechanical strength and carbon dioxide adsorption capacity of the composite material, and the use of this binder causes less environmental pollution.

[0019] In some embodiments, the molecular sieve is preferably one or more of type A molecular sieve and type X molecular sieve; by using the preferred type of molecular sieve, it is beneficial to obtain better carbon dioxide adsorption performance.

[0020] In some embodiments, the activated carbon is selected from one or more of activated carbon prepared from liquefaction residue, coal-based activated carbon, and coconut shell activated carbon, and preferably activated carbon prepared from liquefaction residue. By using the preferred activated carbon, it is beneficial to further improve the comprehensive performance of the composite material.

[0021] In a more preferred embodiment, the binder is selected from carboxymethyl cellulose, the activated carbon is selected from activated carbon prepared from liquefaction residue, and the mass of the molecular sieve is 8-24% of the mass of the activated carbon. By preparing the composite material by the preparation method of the preferred embodiment, more excellent comprehensive performance can be obtained, and more excellent mechanical strength and carbon dioxide adsorption capacity can be achieved at the same time.

[0022] In some embodiments, in step (2), the dispersion includes first stirring and then ultrasonic dispersion, for example, ultrasonic dispersion for 15-25 minutes;

[0023] In some embodiments, in step (4), the clay kneading includes kneading the clay material in a vacuum clay kneader for multiple times, for example, kneading 3-5 times, such as 3, 4, or 5 times, etc.;

[0024] In some embodiments, in step (4), the standing and aging time is 18-30 h, such as 18, 20, 14, 28, or 30 h, etc.

[0025] In some embodiments, in step (5), the shaping is to extrude the mud into strips;

[0026] In some embodiments, the drying is natural drying at room temperature, preferably natural drying under conditions of avoiding light and wind, and preferably the drying time is 3 - 6 days, such as 3, 4, 5 or 6 days, etc.

[0027] In some embodiments, in step (5), the temperature of the heating carbonization ≥ 450 °C.

[0028] Preferably, the temperature of the heating carbonization is 450 - 700 °C, such as 450 °C, 500 °C, 600 °C or 700 °C, etc.

[0029] In some embodiments, the heating carbonization is carried out in a nitrogen atmosphere.

[0030] The present invention also provides an activated carbon - molecular sieve composite material prepared by the preparation method described above.

[0031] The present invention also provides the application of the activated carbon - molecular sieve composite material described above, using the activated carbon - molecular sieve composite material for the purification of flue gas. Preferably, the flue gas is wet flue gas; preferably, the activated carbon - molecular sieve composite material is used for the adsorption of carbon dioxide in flue gas.

[0032] The technical solution provided by the present invention has the following beneficial effects:

[0033] The preparation method provided by the present invention, each component is combined in a specific dosage and the activated carbon - molecular sieve composite material is prepared in a specific order. The finally prepared composite material can take into account good mechanical strength and carbon dioxide adsorption capacity, with a low powdering rate, and at the same time has good water resistance. The preparation method provided by the present invention has a simple process, does not need to introduce other components such as acids and alkalis, does not produce waste liquids such as acids and alkalis, and the obtained composite material is particularly suitable for the adsorption and separation of carbon dioxide in wet flue gas. Specific Embodiments

[0034] For the convenience of understanding the present invention, the present invention will be further described below in conjunction with embodiments. It should be understood that the following embodiments are only for better understanding of the present invention, and do not mean that the present invention is only limited to the following embodiments.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. The term "and / or" as used herein may include any and all combinations of one or more of the related listed items.

[0036] Where specific experimental steps or conditions are not specified in the examples, the operations or conditions of the corresponding conventional experimental steps in this technical field can be followed. For reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0037] Raw material description:

[0038] Bituminous coal-based activated carbon: Shijiazhuang Hongsen Activated Carbon Co., Ltd., bituminous coal-based activated carbon powder with an iodine value of 800;

[0039] Coconut shell-based activated carbon: Henan Zhongju Activated Carbon Co., Ltd., coconut shell-based activated carbon powder with an iodine value of 800;

[0040] Liquefaction residue-based activated carbon: Prepared from the liquefaction residue raw material of China Shenhua Ordos Coal Liquefaction Company. The preparation method refers to "Preparation and Performance Optimization of CO2 Adsorbents Based on Liquefaction Residue" (DOI: 10.16085 / j.issn.1000 - 6613.2023 - 0090). Specifically: Take liquefaction residue (ash content 2wt%) and potassium nitrate and mix and grind them evenly according to a mass ratio of 10:3. Heat from room temperature to 300°C at a rate of 10°C / min under air conditions, and after constant temperature treatment for 60 min, obtain a pre-oxidized sample; then mix and grind it evenly with potassium hydroxide according to a mass ratio of 1:1, and heat to 650°C at a heating rate of 5°C / min in a nitrogen atmosphere in a tubular furnace for 60 min for carbonization and activation treatment. The carbonized and activated sample is treated in a 5wt% dilute hydrochloric acid solution for 20 min; finally, the acid-treated sample is washed with deionized water until neutral, and dried in a forced-air drying oven at 120°C to obtain an activated carbon sample.

[0041] 13X molecular sieve: 200-mesh powdered sample purchased from Zhuoran Environmental Protection Co., Ltd.;

[0042] 4A molecular sieve: 200-mesh powdered sample purchased from Zhuoran Environmental Protection Co., Ltd.;

[0043] Testing method description:

[0044] Testing method for the strength of the composite material: GB / T7702.3 - 2008 Test Methods for Coal-based Granular Activated Carbon - Determination of Strength;

[0045] Adsorption capacity of the composite material: Add a certain amount of the sample to a fixed adsorption bed, pretreat it at 120°C for 30 min to allow the sample to discharge impurities, then cool it to 40°C, and introduce a mixed gas (composition: 15% (v / v) CO2 and 85% (v / v) N2). Calculate the adsorption capacity according to the adsorption breakthrough curve of the sample. Repeat the test three times, and take the average of the three tests as the experimental result and list it in Table 2.

[0046] Water resistance: Place the sample in water for one week to see if it dissolves.

[0047] Example 1

[0048] An activated carbon-molecular sieve composite material, the weight percentage of the raw materials for preparing the activated carbon is: 80% of activated carbon, 10% of 13X molecular sieve and 10% of carboxymethyl cellulose.

[0049] The method for preparing an activated carbon-molecular sieve composite material comprises the following steps:

[0050] (1) Add 1 kg of carboxymethyl cellulose to 10 kg of water and stir continuously until the carboxymethyl cellulose is completely dissolved and the solution becomes colorless and transparent;

[0051] (2) adding 1 kg of 13X molecular sieve powder to the solution of step (1) and ultrasonically dispersing for 20 minutes until the solution turns into a white emulsion;

[0052] (3) Pour the white emulsion in step (2) into 8 kg of activated carbon powder (coal-based activated carbon) and stir continuously. As the stirring proceeds, the raw material begins to form a sticky mass of mud;

[0053] (4) placing the clay material in step (3) into a vacuum clay machine and repeatedly kneading it for 5 times, and leaving it to stand for 24 hours;

[0054] (5) placing the clay material after standing in step (4) into a hydraulic press, extruding it into strips, and drying it naturally at room temperature in a dark and wind-proof environment for 4 days to obtain dried activated carbon-molecular sieve strips;

[0055] The dried activated carbon-molecular sieve strips were heated and carbonized in a nitrogen atmosphere, and maintained at a carbonization temperature of 650°C for 5 hours (ie, the "carbonization time"). After natural cooling, they were taken out and cut into cylindrical segments of uniform size.

[0056] Embodiment 2-6

[0057] The process was carried out with reference to Example 1, except that the amounts of the components and the process conditions were changed. The specific changes are shown in Tables 1 and 2.

[0058] Example 7

[0059] The preparation was carried out in accordance with Example 4, except that the amount of each component was changed. The specific preparation steps are as follows:

[0060] (1) Add 1.5 kg of carboxymethyl cellulose to 9.2 kg of water and stir continuously until the carboxymethyl cellulose is completely dissolved and the solution becomes colorless and transparent;

[0061] (2) adding 0.5 kg of 13X molecular sieve powder to the solution of step (1) and ultrasonically dispersing for 20 minutes until the solution becomes a white emulsion;

[0062] (3) Pour the white emulsion in step (2) into 8 kg of liquefied residue-based activated carbon powder and continuously stir. As the stirring progresses, the raw materials begin to form a viscous lump-shaped mud.

[0063] (4) Put the mud in step (3) into a vacuum pug mill and knead it repeatedly 5 times, then let it stand and age for 24 hours.

[0064] (5) Put the mud after standing in step (4) into a hydraulic press to extrude it into strips and naturally dry it in the dark and wind-free at room temperature for 3 days to obtain dried activated carbon-molecular sieve strips.

[0065] Heat and carbonize the dried activated carbon-molecular sieve strips under a nitrogen atmosphere, maintain them at a carbonization temperature of 550 °C for 3 hours (i.e., "carbonization time"), take them out after natural cooling, and cut them into uniformly sized cylindrical segments.

[0066] Compared with Example 4, the main difference in Example 7 is that the preferred dosage of molecular sieve is not used, and as a result, both the mechanical strength and the carbon dioxide adsorption capacity decrease; while Example 4 can achieve better mechanical strength and carbon dioxide adsorption capacity.

[0067] Example 8

[0068] It is carried out with reference to Example 4, and the only difference is that the binder used is carboxymethyl cellulose. The specific preparation steps are as follows:

[0069] (1) Add 1.5 kg of carboxymethyl cellulose to 9.2 kg of water and continuously stir until the carboxymethyl cellulose is completely dissolved and the solution becomes colorless and transparent.

[0070] (2) Add 0.9 kg of 13X molecular sieve powder to the solution in step (1) and ultrasonically disperse it for 20 minutes, and the solution becomes a white emulsion.

[0071] (3) Pour the white emulsion in step (2) into 7.6 kg of liquefied residue-based activated carbon powder and continuously stir. As the stirring progresses, the raw materials begin to form a viscous lump-shaped mud.

[0072] (4) Put the mud in step (3) into a vacuum pug mill and knead it repeatedly 5 times, then let it stand and age for 24 hours.

[0073] (5) Put the mud after standing in step (4) into a hydraulic press to extrude it into strips and naturally dry it in the dark and wind-free at room temperature for 3 days to obtain dried activated carbon-molecular sieve strips.

[0074] Heat and carbonize the dried activated carbon-molecular sieve strips under a nitrogen atmosphere, maintain them at a carbonization temperature of 550 °C for 3 hours (i.e., "carbonization time"), take them out after natural cooling, and cut them into uniformly sized cylindrical segments.

[0075] Compared with Example 4, Example 8 differs only in that the preferred binder carboxymethyl cellulose is not used, and as a result, both the mechanical strength and the carbon dioxide adsorption capacity are significantly reduced. It can be seen that in the preparation system of the present invention, under the same other conditions, the use of the preferred carboxymethyl cellulose is conducive to further improving the mechanical strength and carbon dioxide adsorption capacity.

[0076] Comparative Example 1 (Compared with Example 4, the amount of binder used is reduced)

[0077] The method for preparing an activated carbon-molecular sieve composite material comprises the following steps:

[0078] (1) Add 0.5 kg of carboxymethyl cellulose to 9.2 kg of water and stir continuously until the carboxymethyl cellulose is completely dissolved and the solution becomes colorless and transparent;

[0079] (2) adding 0.9 kg of 13X molecular sieve powder to the solution of step (1) and ultrasonically dispersing for 20 minutes until the solution turns into a white emulsion;

[0080] (3) Pour the white emulsion in step (2) into 7.6 kg of liquefied residue-based activated carbon powder and stir continuously. As the stirring proceeds, the raw material begins to form a sticky mass of mud;

[0081] (4) placing the clay material in step (3) in a vacuum clay machine and repeatedly kneading it for 5 times, and leaving it to stand for 24 hours;

[0082] (5) placing the clay material after standing in step (4) into a hydraulic press, extruding it into strips, and drying it naturally at room temperature in a dark and wind-proof environment for 3 days to obtain dried activated carbon-molecular sieve strips;

[0083] The dried activated carbon-molecular sieve strips were heated and carbonized in a nitrogen atmosphere, and kept at a carbonization temperature of 550°C for 3 hours (i.e., "carbonization time"). After natural cooling, they were taken out and found that most of the samples had been powdered and could not be well formed. The strength test of the sieved part of the sample after forming was performed, and the result showed that the strength was only 76%, which was difficult to achieve good mechanical strength.

[0084] Comparative Example 2

[0085] The same method as in Example 4 was used, except that the amount of the binder carboxymethyl cellulose was increased to 1.9 kg, which was 25% of the mass of the activated carbon. The specific preparation steps were as follows:

[0086] (1) Add 1.9 kg of carboxymethyl cellulose to 9.2 kg of water and stir continuously until the carboxymethyl cellulose is completely dissolved and the solution becomes colorless and transparent;

[0087] (2) Add 0.9 kg of 13X molecular sieve powder to the solution in step (1) and ultrasonically disperse it for 20 minutes. The solution becomes a white emulsion.

[0088] (3) Pour the white emulsion in step (2) into 7.6 kg of liquefied residue-based activated carbon powder and continuously stir. As the stirring progresses, the raw materials begin to form a viscous mass of mud.

[0089] (4) Put the mud in step (3) into a vacuum pug mill and knead it repeatedly 5 times, then let it stand and age for 24 hours.

[0090] (5) Put the aged mud in step (4) into a hydraulic press to extrude it into strips and naturally dry it in the dark and windless at room temperature for 3 days to obtain dried activated carbon-molecular sieve strips.

[0091] Heat and carbonize the dried activated carbon-molecular sieve strips under a nitrogen atmosphere, maintain at a carbonization temperature of 550 °C for 3 hours (i.e., "carbonization time"), take them out after natural cooling, and cut them into uniformly sized cylindrical segments.

[0092] The process conditions and experimental results are shown in Tables 1 and 2. It can be seen from the experimental results that when the binder dosage is higher than 20%, although the obtained composite material has better strength, the carbon dioxide adsorption capacity decreases significantly, and it is difficult to reach a level above 5%.

[0093] Comparative Example 3

[0094] It is carried out with reference to Example 4, only different in that: the one-step mixing method is adopted. The specific preparation steps are as follows:

[0095] (1) Add 1.5 kg of carboxymethyl cellulose, 0.9 kg of 13X molecular sieve powder and 7.6 kg of liquefied residue-based activated carbon powder into 9.2 kg of water at the same time, and continuously mix and stir until a mass of mud is formed.

[0096] (2) Put the mud in step (1) into a vacuum pug mill and knead it repeatedly 5 times, then let it stand and age for 24 hours.

[0097] (3) Put the aged mud in step (2) into a hydraulic press to extrude it into strips and naturally dry it in the dark and windless at room temperature for 3 days to obtain dried activated carbon-molecular sieve strips.

[0098] Heat and carbonize the dried activated carbon-molecular sieve strips under a nitrogen atmosphere, maintain at a carbonization temperature of 550 °C for 3 hours (i.e., "carbonization time"), take them out after natural cooling, and cut them into uniformly sized cylindrical segments.

[0099] Results: During the preparation of this sample, it was difficult to disperse each component evenly, and the resulting composite material had poor uniformity. When performing performance tests on this sample, especially during the adsorption performance test, the repeatability of the results obtained from three repeated tests was very poor. The carbon dioxide adsorption amount fluctuated between 4.5 - 6.8 wt%, and the difference between the three test results exceeded 30%. In Examples 1 - 8 of the present invention, the difference between the results of three adsorption performance tests was within 0.1 - 0.3%, and the sample had good uniformity. The strength test result of the sample in this comparative example was 85%.

[0100] Comparative Example 4

[0101] It was carried out with reference to Example 2, with the only difference being: changing the mixing order of each component. The specific preparation steps are as follows:

[0102] (1) Add 7.5 kg of coconut shell activated carbon powder to 9.8 kg of water and stir continuously until the solution turns black;

[0103] (2) Add 1.3 kg of carboxymethyl cellulose to the solution in step (1) and stir continuously. As the stirring progresses, small lump-like mud materials start to gradually form;

[0104] (3) Add 2.2 kg of 4A molecular sieve powder to the lump-like mud material in step (2). First, the molecular sieve powder adheres to the surface of the mud material and then mixes into the mud material as the stirring continues;

[0105] (4) Put the mud material in step (3) into a vacuum pug mill and knead it repeatedly 3 times, then let it stand and age for 24 hours;

[0106] (5) Put the aged mud material in step (4) into a hydraulic press to extrude it into strips and let it dry naturally in the dark, avoiding wind, at room temperature for 4 days to obtain dried activated carbon - molecular sieve strips;

[0107] Heat and carbonize the dried activated carbon - molecular sieve strips in a nitrogen atmosphere, maintain at a carbonization temperature of 500 °C for 5 hours (i.e., "carbonization time"), take them out after natural cooling, and cut them into uniformly sized cylindrical segments.

[0108] From the experimental results of Example 2 and Comparative Example 4, it can be seen that under the same other conditions, Comparative Example 4 did not prepare the composite material according to the mixing order of the present invention, and as a result, both the mechanical strength and carbon dioxide adsorption capacity of the obtained composite material decreased significantly compared to Example 2. It can be seen that under the same other conditions, preparing the mixture of each component and the composite material according to the specific process sequence of the present invention can significantly take into account the improvement of both mechanical strength and carbon dioxide adsorption capacity.

[0109] Table 1: Dosage of each raw material in each example

[0110]

[0111]

[0112] Table 2: Conditions of Each Step in Each Example

[0113]

[0114] It can be seen from the comparison between Example 3 and Example 4 that, under the condition that other conditions are the same, it is preferably to use liquefied residue-based activated carbon, which is beneficial to further significantly improve the mechanical strength and carbon dioxide adsorption capacity of the composite material.

[0115] Through the comparison between Example 2 and Example 6, under the condition that other conditions are basically the same, Example 2 did not adopt the preferred dosage of molecular sieve (8-24% of the mass of activated carbon), and as a result, both the mechanical strength and carbon dioxide adsorption of the obtained composite material decreased; similarly, through the comparison between Example 7 and Example 4, under the condition that other conditions are basically the same, Example 7 did not adopt the preferred dosage of molecular sieve (8-24% of the mass of activated carbon), and as a result, both the mechanical strength and carbon dioxide adsorption of the obtained composite material decreased.

[0116] Among Examples 1-8 adopting the preparation process of the present invention, the effect of Example 4 is better. Example 4 simultaneously adopts the preferred activated carbon (liquefied residue-based activated carbon) and the preferred binder (carboxymethyl cellulose), and simultaneously controls the mass of the molecular sieve to be 8-24% of the mass of the activated carbon. The obtained composite material has better comprehensive performance and can balance more excellent mechanical strength and carbon dioxide adsorption capacity.

[0117] In the above Examples 1-8, no obvious dissolution phenomenon occurred in the water resistance test of the obtained composite material, and it has better water resistance.

[0118] It is easy to understand that the above examples are merely illustrations for clear explanation and do not mean that the present invention is only limited thereto. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A preparation method of an activated carbon - molecular sieve composite material, characterized in that, It includes the following steps: (1) Dissolve the binder in water. The binder is selected from one or more of carboxymethyl cellulose, carboxyethyl cellulose, and phenolic resin; (2) Add the molecular sieve powder to the solution obtained in step (1) and perform ultrasonic dispersion to obtain an emulsion; (3) Mix and stir the emulsion and activated carbon powder to form a mud; (4) Knead the mud, and then let it stand and age; (5) Shape and dry the mud obtained in step (4), and then heat and carbonize it; Wherein, the dosage of the binder is 10-20% of the mass of the activated carbon, the dosage of the molecular sieve is 5-30% of the mass of the activated carbon, and the dosage of water is 0.8-1.2 times the total mass of the binder, the molecular sieve, and the activated carbon.

2. The preparation method according to claim 1, wherein, The mass of the molecular sieve is 8-24% of the mass of the activated carbon.

3. The preparation method according to claim 1 or 2, characterized in that, The binder is selected from carboxymethyl cellulose.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The molecular sieve is one or more of A-type molecular sieve and X-type molecular sieve; And / or, the activated carbon is selected from one or more of activated carbon prepared from liquefaction residue, coal-based activated carbon, and coconut shell activated carbon, preferably activated carbon prepared from liquefaction residue.

5. The preparation method according to any one of claims 1-4, characterized in that, The binder is selected from carboxymethyl cellulose, the activated carbon is selected from activated carbon prepared from liquefaction residue, and the mass of the molecular sieve is 8-24% of the mass of the activated carbon.

6. The preparation method according to any one of claims 1-5, characterized in that, In step (4), the kneading includes kneading the mud in a vacuum kneader for multiple times, such as kneading 3-5 times; And / or, in step (4), the time for standing and aging is 18-30h.

7. The preparation method according to any one of claims 1-6, characterized in that, In step (5), the shaping is to extrude the mud into strips; And / or, the drying is natural drying at room temperature, preferably natural drying under light- and wind-proof conditions, and preferably the drying time is 3-6 days; And / or, in step (5), the temperature for heating and carbonizing is ≥450°C, and the carbonization time is, for example, 3-6h; preferably, the temperature for heating and carbonizing is 450-700°C.

8. The preparation method according to any one of claims 1 to 7, characterized in that, The heating and carbonization are carried out under air-insulated conditions, such as in a nitrogen atmosphere.

9. An activated carbon-molecular sieve composite material prepared by the preparation method according to any one of claims 1-8.

10. Use of the activated carbon-molecular sieve composite material according to claim 9, characterized in that, Use the activated carbon-molecular sieve composite material for the purification of flue gas. Preferably, the flue gas is wet flue gas; preferably, the activated carbon-molecular sieve composite material is used for the adsorption of carbon dioxide in the flue gas.

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