Preparation method of high-performance activated carbon for carbon tank

Abstract

The invention belongs to the technical field of activated carbon, and particularly relates to a preparation method of high-performance activated carbon for a carbon tank. The modified activated carbon is obtained by doping the boron quantum dots, and the bentonite composite material and the carbon dot-containing polyvinyl alcohol are used together, so that the specific surface area of the activated carbon for the carbon tank is effectively increased, the strength is improved, and meanwhile, the butane working capacity is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon, and in particular relates to a method for preparing high-performance activated carbon for a carbon canister. Background Art

[0002] During the storage, transportation and use of gasoline, there will be the problem of oil evaporation loss; with the increasingly stringent standards for motor vehicle exhaust emissions, the proportion of automobile exhaust emissions in the total vehicle pollution emissions is getting smaller and smaller, while the proportion of pollutants generated by fuel tanks and carburetors is becoming increasingly prominent. At present, adsorption is a commonly used method in oil and gas recovery, and the key material of this technology is activated carbon. As a porous carbon-containing substance, activated carbon has a highly developed pore structure and special surface properties. It is an excellent adsorbent and is widely used in the field of oil and gas recovery. The carbon canister with activated carbon as the core can store the escaped oil and gas in the activated carbon of the carbon canister through adsorption, and reuse this part of the oil and gas through the desorption process, which plays a role in energy saving and environmental protection.

[0003] Phosphoric acid-based wood activated carbon is a process in which wood raw materials (such as sawdust, fruit shells, etc.) are chemically activated at high temperatures using phosphoric acid as an activator. Although the process is relatively mature, the following problems still exist due to its limitations: (1) During the phosphoric acid-based activation process, the formation of the pore structure is affected by many factors (such as phosphoric acid concentration, heating temperature, time, etc.), resulting in a wide distribution of the pore structure. The effective pore structure distribution is also difficult to regionalize and target due to the single activator. (2) In the phosphoric acid-based wood activated carbon preparation process, phosphoric acid reacts with wood cellulose raw materials to generate adhesive substances, achieving self-adhesion and enabling molding and granulation. However, the adhesive substances generated by the reaction system have weak adhesive force after activation, which in turn affects the mechanical strength and other properties of the product. (3) The differences in phosphoric acid recovery in the phosphoric acid-based wood activated carbon preparation process result in different degrees of removal of phosphates generated by the phosphoric acid side reaction during activation, resulting in pore blockage and affecting the butane working capacity.

[0004] Therefore, there is an urgent need for a high-performance activated carbon for carbon canisters. By modifying the activated carbon raw materials and introducing other functional components, the specific surface area and strength of the activated carbon can be increased, while the butane working capacity can be improved. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing high-performance activated carbon for carbon canisters. Modified activated carbon is obtained by doping with boron quantum dots, and the combined use of bentonite composite materials and carbon-dot-containing polyvinyl alcohol can effectively increase the specific surface area and strength of the activated carbon for carbon canisters, while also increasing the butane working capacity.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing high-performance activated carbon for a carbon canister, comprising the following steps:

[0008] Step S1: adding 4 to 6 parts of acetic acid to 200 to 220 parts of deionized water, and then adding 8 to 12 parts of activated carbon and 4 to 6 parts of boron quantum dots, stirring for 2 to 4 hours to obtain a dispersion; freezing the dispersion at -4°C for 20 to 24 hours, and then freeze-drying to obtain modified activated carbon;

[0009] Step S2: by weight, 90 to 100 parts of modified activated carbon, 20 to 30 parts of bentonite, 6 to 8 parts of cellulose, 1 to 3 parts of polyvinyl alcohol and 180 to 220 parts of deionized water are mixed uniformly to obtain a mixture;

[0010] Step S3: placing the mixture in a mold, extruding and molding the mixture to obtain a green body, and sintering the green body to obtain high-performance activated carbon for a carbon canister.

[0011] As a preferred solution, the average particle size of the activated carbon is 90-110 meshes.

[0012] As a preferred scheme, the preparation method of the boron quantum dots comprises: adding 2 to 4 parts of boron powder to 70 to 80 parts of isopropanol by weight and mixing evenly, then adding 3 to 5 parts of boric acid and 8 to 10 parts of hydrogen peroxide, ultrasonically crushing at a power of 580 to 600 W for 2 to 4 hours, adding 2 to 4 parts of sodium borohydride after the ultrasonic crushing, stirring for 20 to 24 hours, centrifuging to obtain a supernatant, adding 1 to 3 parts of hydrazine hydrate to the supernatant, ultrasonically shaking for 10 to 20 minutes, and freeze-drying to obtain the boron quantum dots.

[0013] Boron quantum dots in modified activated carbon can be incorporated into the lattice structure of activated carbon, replacing some carbon atoms to form defects or new active sites; by doping, the structure of activated carbon is changed, its chemical activity is improved, and the development of pore structure is affected, thereby increasing the specific surface area of ​​activated carbon for carbon canisters.

[0014] As a preferred solution, the bentonite is a bentonite composite material; the preparation method of the bentonite composite material comprises: mixing 8 to 10 parts of acetic acid and 100 to 120 parts of deionized water by weight, then adding 4 to 6 parts of chitosan and stirring for 2 to 4 hours, then adding 6 to 8 parts of dimethyldiallyl ammonium chloride for stirring reaction, cooling to room temperature after the stirring reaction is completed, adding 90 to 100 parts of acetone, centrifuging, washing the precipitate with anhydrous ethanol, and drying to obtain quaternized chitosan; mixing 4 to 8 parts of acetic acid and 100 to 120 parts of deionized water, then adding 4 to 6 parts of bentonite and 2 to 4 parts of the quaternized chitosan and stirring for 40 to 60 minutes, filtering, washing with water, and drying to obtain the bentonite composite material.

[0015] As a preferred solution, the stirring reaction conditions include: a stirring speed of 200 to 400 r / min, a temperature of 50 to 60° C., and a time of 20 to 30 min.

[0016] The bentonite in the bentonite composite material can fill the pores of the activated carbon, and chitosan can act as a binder to form a carbon cross-linked network during the subsequent sintering process. The bentonite is evenly distributed in the activated carbon matrix to increase the mechanical strength, and the cross-linking effect of chitosan further improves the stability of the material. The synergistic effect improves the strength of the activated carbon for carbon canisters.

[0017] As a preferred scheme, the polyvinyl alcohol is polyvinyl alcohol containing carbon dots; the preparation method of the polyvinyl alcohol containing carbon dots comprises: adding 6 to 8 parts of polyvinyl alcohol to 80 to 100 parts of deionized water by weight, stirring at 70 to 80° C. for 2 to 4 hours, then adding 10 to 20 parts of carbon dot solution and stirring for 40 to 60 minutes, and freeze-drying to obtain polyvinyl alcohol containing carbon dots.

[0018] As a preferred solution, the preparation method of the carbon dot solution includes: adding 4 to 6 parts of split wood to 200 to 220 parts of deionized water by weight and stirring for 40 to 60 minutes, then transferring to a stainless steel high-pressure reactor for heating reaction, naturally cooling after the heating reaction is completed, centrifuging to obtain a reaction liquid, and filtering the reaction liquid with a microporous filter membrane to obtain the carbon dot solution.

[0019] As a preferred solution, the conditions for the heating reaction include: a temperature of 190 to 200° C. and a time of 6 to 8 hours.

[0020] Carbon-dot-containing polyvinyl alcohol can enhance the surface polarity of the material by doping with carbon dots, introduce new adsorption sites, and improve the adsorption capacity of butane molecules, thereby effectively improving the butane working capacity of activated carbon for carbon canisters.

[0021] As a preferred solution, the cellulose is carboxymethyl cellulose and hydroxypropyl cellulose; the mass ratio of the carboxymethyl cellulose to the hydroxypropyl cellulose is (1-2):1.

[0022] By limiting the mass ratio of carboxymethyl cellulose and hydroxypropyl cellulose and ensuring the compounding effect of carboxymethyl cellulose and hydroxypropyl cellulose, the specific surface area and butane working capacity of activated carbon for carbon canisters can be increased, while the strength can be effectively improved.

[0023] As a preferred solution, the sintering conditions include: a sintering temperature of 620-680° C. and a sintering time of 2-4 hours.

[0024] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0025] 1. The bentonite composite material of the present invention uses the lamellar structure of bentonite as a carrier. At the same time, chitosan contains active groups of amino and hydroxyl groups, which can be combined with polyvinyl alcohol containing carbon points at room temperature, and can also be easily adsorbed with modified activated carbon to form an interconnected structure; and during the high-temperature sintering process, the interconnected structure at room temperature is gradually carbonized into a porous carbon network, which effectively improves the specific surface area and butane working capacity of the activated carbon for the carbon canister, and the boron quantum dots in the modified activated carbon and the carbon dots in the polyvinyl alcohol containing carbon points will also migrate during the sintering process, focus on the lamellar structure of bentonite and form a composite material, which significantly improves the strength of the activated carbon for the carbon canister.

[0026] 2. The boron quantum dots in the modified activated carbon of the present invention can be incorporated into the lattice structure of the activated carbon, replacing some carbon atoms to form defects or new active sites; by doping, the structure of the activated carbon is changed, its chemical activity is improved, and the development of the pore structure is affected, thereby increasing the specific surface area of ​​the activated carbon for the carbon canister.

[0027] 3. The bentonite in the bentonite composite material of the present invention can fill the pores of the activated carbon, and chitosan can act as a binder to form a carbon cross-linked network in the subsequent sintering process. The bentonite is evenly distributed in the activated carbon matrix to increase the mechanical strength, and the cross-linking effect of chitosan further improves the stability of the material, and the synergistic effect improves the strength of the activated carbon for the carbon canister.

[0028] 4. The carbon-dot-containing polyvinyl alcohol of the present invention can enhance the surface polarity of the material by doping with carbon dots, introduce new adsorption sites, and improve the adsorption capacity of butane molecules, thereby effectively improving the butane working capacity of the activated carbon for the carbon canister. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The sources of some components in the embodiments and comparative examples are as follows:

[0031] Activated carbon I, from Fujian Xinsen Carbon Industry Co., Ltd.;

[0032] Bentonite, CAS No. 1302-78-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0033] Carboxymethyl cellulose, CAS No. 9004-32-4, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0034] Hydroxypropyl cellulose, CAS No. 9004-64-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0035] Polyvinyl alcohol, product number P139540, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0036] Boron powder, CAS No. 7440-42-8, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0037] Isopropyl alcohol, CAS No. 67-63-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0038] Boric acid, CAS No. 10043-35-3, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0039] Hydrogen peroxide, CAS No. 7722-84-1, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0040] Sodium borohydride, CAS No. 16940-66-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0041] Hydrazine hydrate, CAS No. 10217-52-4, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0042] Acetic acid, CAS No. 64-19-7, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0043] Chitosan, product number C105799, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0044] Dimethyldiallylammonium chloride, CAS No. 7398-69-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0045] Acetone, CAS No. 67-64-1, CAS No. 7398-69-8, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0046] The heartwood was purchased from Mingjie Biotechnology Co., Ltd.

[0047] Example 1

[0048] This embodiment provides a method for preparing high-performance activated carbon for a carbon canister, comprising the following steps:

[0049] Preparation of boron quantum dots: In parts by weight, 4 parts of boron powder are added to 80 parts of isopropanol and mixed evenly, then 5 parts of boric acid and 10 parts of hydrogen peroxide are added, and ultrasonic crushing is performed at a power of 600 W for 2 hours. After the ultrasonic crushing, 4 parts of sodium borohydride are added and stirred for 24 hours. The supernatant is obtained by centrifugation, and 3 parts of hydrazine hydrate are added to the supernatant and ultrasonically shaken for 20 minutes, and freeze-dried to obtain the boron quantum dots.

[0050] Preparation of bentonite composite material: by weight, 10 parts of acetic acid and 120 parts of deionized water are mixed evenly, then 6 parts of chitosan are added and stirred for 4 hours, and then 8 parts of dimethyldiallyl ammonium chloride are added for stirring reaction (stirring speed is 400r / min, temperature is 60°C, time is 20min), after the stirring reaction is completed, it is cooled to room temperature, 100 parts of acetone are added, centrifuged, the precipitate is washed with anhydrous ethanol, and dried to obtain quaternized chitosan; 8 parts of acetic acid and 120 parts of deionized water are mixed evenly, then 6 parts of bentonite and 4 parts of the quaternized chitosan are added and stirred for 60min, filtered, washed with water, and dried to obtain a bentonite composite material.

[0051] Preparation of polyvinyl alcohol containing carbon dots: (1) By weight, add 6 parts of split wood to 220 parts of deionized water and stir for 60 minutes, then transfer to a stainless steel autoclave for heating reaction (temperature of 200°C, time of 6 hours), cool naturally after the heating reaction is completed, centrifuge to obtain a reaction liquid, filter the reaction liquid with a microporous filter membrane to obtain a carbon dot solution. (2) By weight, add 8 parts of polyvinyl alcohol to 100 parts of deionized water, stir at 80°C for 2 hours, then add 20 parts of the carbon dot solution and stir for 60 minutes, and freeze-dry to obtain polyvinyl alcohol containing carbon dots.

[0052] Step S1: In parts by weight, 6 parts of acetic acid are added to 220 parts of deionized water, and then 12 parts of activated carbon I and 6 parts of boron quantum dots are added and stirred for 4 hours to obtain a dispersion; the dispersion is frozen at -4°C for 24 hours, and then freeze-dried to obtain modified activated carbon;

[0053] Step S2: by weight, 100 parts of modified activated carbon, 30 parts of bentonite composite material, 6 parts of cellulose (4 parts of carboxymethyl cellulose and 2 parts of hydroxypropyl cellulose), 3 parts of carbon point-containing polyvinyl alcohol and 220 parts of deionized water are mixed uniformly to obtain a mixture;

[0054] Step S3: placing the mixture in a mold, extruding and molding to obtain a green body, and sintering the green body (sintering temperature is 680° C., sintering time is 2 h) to obtain high-performance activated carbon for carbon canisters.

[0055] Example 2

[0056] This embodiment provides a method for preparing high-performance activated carbon for a carbon canister, comprising the following steps:

[0057] Preparation of boron quantum dots: In parts by weight, 2 parts of boron powder are added to 70 parts of isopropanol and mixed evenly, then 3 parts of boric acid and 8 parts of hydrogen peroxide are added, and ultrasonic crushing is performed at a power of 580 W for 4 hours. After the ultrasonic crushing, 2 parts of sodium borohydride are added and stirred for 20 hours. The supernatant is obtained by centrifugation, 1 part of hydrazine hydrate is added to the supernatant, ultrasonically shaken for 10 minutes, and freeze-dried to obtain the boron quantum dots.

[0058] Preparation of bentonite composite material: in parts by weight, 8 parts of acetic acid and 100 parts of deionized water are mixed evenly, then 4 parts of chitosan are added and stirred for 2 hours, and then 6 parts of dimethyldiallyl ammonium chloride are added for stirring reaction (stirring speed is 200r / min, temperature is 50°C, time is 30min), after the stirring reaction is completed, it is cooled to room temperature, 90 parts of acetone are added, centrifuged, the precipitate is washed with anhydrous ethanol, and dried to obtain quaternized chitosan; 4 parts of acetic acid and 100 parts of deionized water are mixed evenly, then 4 parts of bentonite and 2 parts of the quaternized chitosan are added and stirred for 40min, filtered, washed with water, and dried to obtain a bentonite composite material.

[0059] Preparation of polyvinyl alcohol containing carbon dots: (1) By weight, 4 parts of split wood were added to 200 parts of deionized water and stirred for 40 minutes, then transferred to a stainless steel autoclave for heating reaction (temperature of 190°C, time of 8 hours), cooled naturally after the heating reaction was completed, centrifuged to obtain a reaction liquid, and the reaction liquid was filtered with a microporous filter membrane to obtain a carbon dot solution. (2) By weight, 6 parts of polyvinyl alcohol were added to 80 parts of deionized water, stirred at 70°C for 4 hours, then 10 parts of the carbon dot solution were added and stirred for 40 minutes, and freeze-dried to obtain polyvinyl alcohol containing carbon dots.

[0060] Step S1: In parts by weight, 4 parts of acetic acid are added to 200 parts of deionized water, and then 8 parts of activated carbon I and 4 parts of boron quantum dots are added and stirred for 2 hours to obtain a dispersion; the dispersion is frozen at -4°C for 20 hours, and then freeze-dried to obtain modified activated carbon;

[0061] Step S2: by weight, 90 parts of modified activated carbon, 20 parts of bentonite composite material, 8 parts of cellulose (4 parts of carboxymethyl cellulose and 4 parts of hydroxypropyl cellulose), 1 part of carbon point-containing polyvinyl alcohol and 180 parts of deionized water are mixed uniformly to obtain a mixture;

[0062] Step S3: placing the mixture in a mold, extruding and molding to obtain a green body, and sintering the green body (sintering temperature is 620° C., sintering time is 4 h) to obtain high-performance activated carbon for a carbon canister.

[0063] Example 3

[0064] This embodiment provides a method for preparing high-performance activated carbon for a carbon canister, comprising the following steps:

[0065] Preparation of boron quantum dots: In parts by weight, 3 parts of boron powder are added to 75 parts of isopropanol and mixed evenly, then 4 parts of boric acid and 9 parts of hydrogen peroxide are added, and ultrasonic crushing is performed at a power of 590 W for 3 hours. After the ultrasonic crushing, 3 parts of sodium borohydride are added and stirred for 22 hours. The supernatant is obtained by centrifugation, and 2 parts of hydrazine hydrate are added to the supernatant and ultrasonically shaken for 15 minutes, and freeze-dried to obtain the boron quantum dots.

[0066] Preparation of bentonite composite material: in parts by weight, 9 parts of acetic acid and 110 parts of deionized water are mixed evenly, then 5 parts of chitosan are added and stirred for 3 hours, and then 7 parts of dimethyldiallyl ammonium chloride are added for stirring reaction (stirring speed is 300r / min, temperature is 55°C, time is 25min), after the stirring reaction is completed, it is cooled to room temperature, 95 parts of acetone are added, centrifuged, the precipitate is washed with anhydrous ethanol, and dried to obtain quaternized chitosan; 6 parts of acetic acid and 110 parts of deionized water are mixed evenly, then 5 parts of bentonite and 3 parts of the quaternized chitosan are added and stirred for 50min, filtered, washed with water, and dried to obtain a bentonite composite material.

[0067] Preparation of polyvinyl alcohol containing carbon dots: (1) By weight, 5 parts of split wood were added to 210 parts of deionized water and stirred for 50 minutes, then transferred to a stainless steel autoclave for heating reaction (temperature of 195°C, time of 7 hours), cooled naturally after the heating reaction was completed, centrifuged to obtain a reaction liquid, and the reaction liquid was filtered with a microporous filter membrane to obtain a carbon dot solution. (2) By weight, 7 parts of polyvinyl alcohol were added to 90 parts of deionized water, stirred at 75°C for 3 hours, then 15 parts of the carbon dot solution were added and stirred for 50 minutes, and freeze-dried to obtain polyvinyl alcohol containing carbon dots.

[0068] Step S1: In parts by weight, 5 parts of acetic acid are added to 210 parts of deionized water, and then 10 parts of activated carbon I and 5 parts of boron quantum dots are added and stirred for 3 hours to obtain a dispersion; the dispersion is frozen at -4°C for 22 hours, and then freeze-dried to obtain modified activated carbon;

[0069] Step S2: by weight, 95 parts of modified activated carbon, 25 parts of bentonite composite material, 7 parts of cellulose (4 parts of carboxymethyl cellulose and 3 parts of hydroxypropyl cellulose), 2 parts of carbon point-containing polyvinyl alcohol and 200 parts of deionized water are mixed uniformly to obtain a mixture;

[0070] Step S3: placing the mixture in a mold, extruding and molding the mixture to obtain a green body, and sintering the green body (sintering temperature is 640° C., sintering time is 3 h) to obtain high-performance activated carbon for a carbon canister.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 1 is that activated carbon I is used instead of modified activated carbon.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that commercially available bentonite is used instead of the bentonite composite material.

[0075] Comparative Example 3

[0076] The difference between this comparative example and Example 1 is that commercially available polyvinyl alcohol is used instead of the carbon-dot-containing polyvinyl alcohol.

[0077] Comparative Example 4

[0078] The difference between this comparative example and Example 1 is that the amount of carboxymethyl cellulose is changed to 5 parts and the amount of hydroxypropyl cellulose is changed to 1 part.

[0079] Comparative Example 5

[0080] The difference between this comparative example and Example 1 is that the amount of carboxymethyl cellulose is changed to 2 parts and the amount of hydroxypropyl cellulose is changed to 4 parts.

[0081] The carbon canisters of the above embodiments and comparative examples were subjected to the following tests using high-performance activated carbon:

[0082] (1) Specific surface area test: refer to the requirements of GB / T 19587-2017 Determination of specific surface area of ​​solid substances by gas adsorption BET method.

[0083] (2) Strength test: Test according to the requirements of GB / T 12496.6-1999 Test method for wood activated carbon - Determination of strength.

[0084] (3) Butane working capacity test: Test according to the requirements of GB / T 20449-2006 Test method for butane working capacity of activated carbon.

[0085] Table 1 Performance test results

[0086] <![CDATA[Specific surface area (m 2 / g)]]> strength(%) Butane working capacity (g / 100mL) Example 1 2738 97.18 16.53 Example 2 2716 97.05 16.37 Example 3 2725 97.12 16.46 Comparative Example 1 2187 89.26 9.39 Comparative Example 2 2198 89.43 9.51 Comparative Example 3 2191 89.35 9.46 Comparative Example 4 2487 93.72 12.07 Comparative Example 5 2494 93.79 12.15

[0087] From the above performance test results, it can be seen that the effects of Examples 1-3 are good, and the specific surface area of ​​activated carbon for carbon canisters is 2716-2738m 2 / g, the strength is 97.05~97.18%, and the butane working capacity is 16.37~16.53g / 100mL; this is because it is modified activated carbon obtained by doping with boron quantum dots, and is used together with bentonite composite materials and carbon-dot-containing polyvinyl alcohol, which effectively increases the specific surface area of ​​activated carbon for carbon canisters and improves its strength, while also improving the butane working capacity.

[0088] However, since the necessary technical solutions were not adopted in the comparative examples, the corresponding performance tests were obviously worse than those of the embodiments. Compared with Example 1, the comparative example 1 used activated carbon I instead of modified activated carbon, and the specific surface area of ​​the activated carbon for the carbon canister became smaller, the strength was reduced, and the butane working capacity was reduced; compared with Example 1, the comparative example 2 used commercially available bentonite instead of the bentonite composite material, and the specific surface area of ​​the activated carbon for the carbon canister became smaller, the strength was reduced, and the butane working capacity was reduced; compared with Example 1, the comparative example 3 used commercially available polyvinyl alcohol instead of carbon point-containing polyvinyl alcohol, and the specific surface area of ​​the activated carbon for the carbon canister became smaller, the strength was reduced, and the butane working capacity was reduced. The amount of carboxymethyl cellulose in comparative example 4 is changed to 5 parts and the amount of hydroxypropyl cellulose is changed to 1 part compared with Example 1. Due to the excessive amount of carboxymethyl cellulose, the compounding effect is not good, the specific surface area of ​​activated carbon for carbon canister becomes smaller, the strength is reduced, and the butane working capacity is reduced; Compared with Example 1, the amount of carboxymethyl cellulose in comparative example 5 is changed to 2 parts and the amount of hydroxypropyl cellulose is changed to 4 parts. Due to the small amount of carboxymethyl cellulose, the compounding effect is not good, the specific surface area of ​​activated carbon for carbon canister becomes smaller, the strength is reduced, and the butane working capacity is reduced. The above experimental results further prove the importance of the technical scheme defined in the present invention for its technical effect.

[0089] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing high-performance activated carbon for a carbon canister, characterized in that: The following steps are involved: Step S1: adding 4 to 6 parts of acetic acid to 200 to 220 parts of deionized water, and then adding 8 to 12 parts of activated carbon and 4 to 6 parts of boron quantum dots, stirring for 2 to 4 hours to obtain a dispersion; freezing the dispersion at -4°C for 20 to 24 hours, and then freeze-drying to obtain modified activated carbon; Step S2: by weight, 90 to 100 parts of modified activated carbon, 20 to 30 parts of bentonite, 6 to 8 parts of cellulose, 1 to 3 parts of polyvinyl alcohol and 180 to 220 parts of deionized water are mixed uniformly to obtain a mixture; Step S3: placing the mixture in a mold, extruding and molding the mixture to obtain a green body, and sintering the green body to obtain high-performance activated carbon for a carbon canister.

2. The method for preparing high-performance activated carbon for a carbon canister according to claim 1, characterized in that: The average particle size of the activated carbon is 90 to 110 meshes.

3. The method for preparing high-performance activated carbon for a carbon canister according to claim 1, characterized in that: The preparation method of the boron quantum dots comprises: adding 2 to 4 parts of boron powder to 70 to 80 parts of isopropanol by weight and mixing evenly, then adding 3 to 5 parts of boric acid and 8 to 10 parts of hydrogen peroxide, ultrasonically crushing for 2 to 4 hours at a power of 580 to 600 W, adding 2 to 4 parts of sodium borohydride after the ultrasonic crushing, stirring for 20 to 24 hours, centrifuging to obtain a supernatant, adding 1 to 3 parts of hydrazine hydrate to the supernatant, ultrasonically shaking for 10 to 20 minutes, and freeze-drying to obtain the boron quantum dots.

4. The method for preparing high-performance activated carbon for a carbon canister according to claim 1, characterized in that: The bentonite is a bentonite composite material; The preparation method of the bentonite composite material comprises: mixing 8 to 10 parts of acetic acid and 100 to 120 parts of deionized water by weight, then adding 4 to 6 parts of chitosan and stirring for 2 to 4 hours, then adding 6 to 8 parts of dimethyldiallyl ammonium chloride for stirring reaction, cooling to room temperature after the stirring reaction is completed, adding 90 to 100 parts of acetone, centrifuging, washing the precipitate with anhydrous ethanol, and drying to obtain quaternized chitosan; mixing 4 to 8 parts of acetic acid and 100 to 120 parts of deionized water, then adding 4 to 6 parts of bentonite and 2 to 4 parts of the quaternized chitosan and stirring for 40 to 60 minutes, filtering, washing with water, and drying to obtain the bentonite composite material.

5. The method for preparing high-performance activated carbon for a carbon canister according to claim 4, characterized in that: The stirring reaction conditions include: a stirring speed of 200 to 400 r / min, a temperature of 50 to 60° C., and a time of 20 to 30 min.

6. The method for preparing high-performance activated carbon for a carbon canister according to claim 1, characterized in that: The polyvinyl alcohol is polyvinyl alcohol containing carbon dots; The preparation method of the carbon-dot-containing polyvinyl alcohol comprises: adding 6 to 8 parts of polyvinyl alcohol to 80 to 100 parts of deionized water by weight, stirring for 2 to 4 hours at 70 to 80° C., then adding 10 to 20 parts of carbon dot solution and stirring for 40 to 60 minutes, and freeze-drying to obtain the carbon-dot-containing polyvinyl alcohol.

7. The method for preparing high-performance activated carbon for a carbon canister according to claim 6, characterized in that: The preparation method of the carbon dot solution comprises: adding 4 to 6 parts of split wood to 200 to 220 parts of deionized water by weight, stirring for 40 to 60 minutes, and then transferring to a stainless steel high-pressure reactor for heating reaction, cooling naturally after the heating reaction is completed, centrifuging to obtain a reaction liquid, and filtering the reaction liquid with a microporous filter membrane to obtain the carbon dot solution.

8. The method for preparing high-performance activated carbon for a carbon canister according to claim 6, characterized in that: The conditions of the heating reaction include: temperature of 190-200° C. and time of 6-8 hours.

9. The method for preparing high-performance activated carbon for a carbon canister according to claim 1, characterized in that: The cellulose is carboxymethyl cellulose and hydroxypropyl cellulose; the mass ratio of the carboxymethyl cellulose to the hydroxypropyl cellulose is (1-2):

1.

10. The method for preparing high-performance activated carbon for a carbon canister according to claim 1 The method is characterized in that The sintering conditions include: sintering temperature is 620-680°C, The sintering time is 2 to 4 hours.