Cylindrical activated carbon with high SO2 removal efficiency and preparation method thereof

Abstract

The present application relates to the technical field of activated carbon, in particular to a kind of columnar activated carbon with high SO2 removal efficiency and a preparation method thereof, comprising the following steps: S1, a first modification treatment of activated carbon, S2, a second modification treatment of activated carbon, S3, preparation of composite activated carbon, and S4, preparation of columnar activated carbon.In the present application, the binder composed of starch, carboxymethyl cellulose and xanthan gum is used as the connecting medium, and the second modified activated carbon and the composite activated carbon are bonded into one after being dried at room temperature, avoiding the influence of high-temperature drying on the activity of the Thiobacillus ferroxidans, thereby obtaining columnar activated carbon.The columnar activated carbon has excellent removal effect on sulfur dioxide, and can efficiently remove sulfur dioxide, thereby reducing the pollution of sulfur dioxide in the atmosphere.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of activated carbon, in particular to a columnar activated carbon with high SO2 removal efficiency and a preparation method thereof. BACKGROUND

[0002] SO2 is one of air pollution, and its main human source is related to energy consumption. Economic development cannot be separated from the support of energy, and China is a big country in energy production and consumption. SO2 is a colorless medium irritating gas, mainly affecting the respiratory tract. Most of the SO2 in the air comes from the process of thermal power generation and industrial production. Inhaling SO2 can damage the respiratory system and aggravate existing respiratory diseases. For people who are easily affected, in addition to changes in lung function, there are also some obvious symptoms such as panting, shortness of breath, and coughing.

[0003] At present, the treatment of polluted gas mainly uses activated carbon for adsorption removal. Activated carbon is a very good adsorbent, which is processed and manufactured by physical and chemical methods such as crushing, screening, catalyst activation, rinsing, drying and screening of coconut shell, bamboo charcoal, various fruit shells and high-quality coal as raw materials. It has the dual characteristics of physical and chemical adsorption, and can selectively adsorb various substances in gas and liquid phases to achieve the purposes of decolorization, sterilization, deodorization and pollution purification. For example, the patent for invention with publication number CN110559988A discloses a preparation method of activated carbon with strong adsorption, which uses carbonized coconut shell as the raw material of activated carbon. Through homogenization, activated carbon with strong adsorption performance and recycling performance is prepared, which has potential application value in the field of environmental protection. The technical scheme improves the adsorption efficiency of activated carbon by increasing the specific surface area of activated carbon. Although the activated carbon has strong adsorption, it does not have specificity for gas, so the activated carbon has strong adsorption effect on all toxic and harmful gases. Therefore, when the activated carbon is needed only for sulfur dioxide with strong adsorption effect, the internal space of the activated carbon has been occupied by a large amount of other types of gas, which cannot provide sufficient space for sulfur dioxide, so it cannot meet the needs of special fields. Therefore, in order to better meet the needs of industry, there is an urgent need for activated carbon with strong adsorption effect for sulfur dioxide. SUMMARY

[0004] The purpose of the present application is to provide a columnar activated carbon with high SO2 removal efficiency and a preparation method thereof.

[0005] In order to achieve the above purpose, the present application provides the following technical scheme:

[0006] A preparation method of a columnar activated carbon with high SO2 removal efficiency, specifically comprising the following steps:

[0007] Primary modification treatment of S1 activated carbon

[0008] 1) The activated carbon is ultrasonically washed with anhydrous ethanol and deionized water respectively, and then dried to obtain pretreated activated carbon;

[0009] 2) The pretreated activated carbon is immersed in sufficient treatment liquid A and treatment liquid B respectively, soaked in a constant temperature water bath for 4-6 h, and then shaken on a shaking table for 20-30 h. After filtration, it is repeatedly washed with deionized water until neutral, dried, and then modified activated carbon is obtained;

[0010] Secondary modification treatment of S2 activated carbon

[0011] 1) Diethyl sulfate is added to ethyl acetate, stirred thoroughly, then transferred to an ice water bath, and then tetramethyl ethylenediamine is slowly added dropwise. The reaction is continued for 12-16 h. After the reaction is completed, the upper clear liquid is taken out, and the remaining liquid is repeatedly washed with ethyl acetate, then transferred to a vacuum drying oven for drying, and a treatment agent is obtained;

[0012] 2) The modified activated carbon is ultrasonically dispersed in anhydrous ethanol to obtain a suspension, the treatment agent is added to the suspension, stirred at room temperature for 10-15 h, then the mixed liquid formed is rotary evaporated to remove anhydrous ethanol, transferred to a vacuum drying oven for drying, and secondary modified activated carbon is obtained;

[0013] Preparation of S3 composite activated carbon

[0014] 1) Thiobacillus ferroxidans is inoculated into the culture medium at an inoculation amount of 10-20%, placed in a culture box, and shaken at 100-150 r / min for 5-10 h. The culture solution is collected, centrifuged, washed, and resuspended in Tris-HCl buffer to obtain a suspension;

[0015] 2) Sodium alginate and polyvinyl alcohol are added to deionized water, stirred in a constant temperature water bath at 90-95℃ until completely dissolved, cooled to room temperature, then the modified activated carbon is added, dispersed uniformly to obtain a dispersion, then an equal volume of the dispersion and the suspension are mixed uniformly, slowly dropped into a saturated calcium salt solution, and constant temperature standing for 8-10 h. The product is taken out and repeatedly washed with normal saline to obtain composite activated carbon;

[0016] Preparation of S4 columnar activated carbon

[0017] Starch, carboxymethyl cellulose, and deionized water are uniformly mixed, heated to 40-45℃, and xanthan gum is added under stirring. The mixture is continuously stirred for 20-30 min to obtain a binder. The secondary modified activated carbon, the composite activated carbon, and the binder are thoroughly mixed, kneaded into a columnar shape, and then dried at room temperature to obtain the desired columnar activated carbon.

[0018] As a further preferred scheme of the present application, the processing liquid A is composed of 5-10 mol / L nitric acid solution, 3-6 mol / L sulfuric acid solution and 5-8 mol / L phosphoric acid solution with a volume ratio of 1:(1-2):(1-2);

[0019] The processing liquid B is composed of 3-7 mol / L sodium hydroxide solution and 10-15 wt% ammonia water with a volume ratio of 1:(2-3).

[0020] As a further preferred scheme of the present application, the water bath temperature is 70-80℃;

[0021] The shaking table oscillation is carried out at 35-40℃ and 300-500 r / min.

[0022] As a further preferred scheme of the present application, the use amount ratio of diethyl sulfate, ethyl acetate and tetramethyl ethylenediamine is (1.5-2.5) g:(200-300) mL:(1.2-1.8) g;

[0023] As a further preferred scheme of the present application, the use amount ratio of modified activated carbon, anhydrous ethanol and processing agent is (1-3) g:(20-50) mL:(1.5-3.0) g;

[0024] The stirring rotation speed is 300-500 r / min.

[0025] As a further preferred scheme of the present application, the culture medium is composed of A liquid and B liquid both of which are subjected to sterilization treatment, and the volume ratio of the two is (7-8):(2-3), wherein the A liquid is composed of ammonium sulfate, potassium chloride, magnesium sulfate, calcium nitrate and distilled water with a mass ratio of (3-5):(0.1-0.5):(0.5-1.2):(0.01-0.06):(700-800);

[0026] The B liquid is composed of ferrous sulfate and distilled water with a mass ratio of (42-50):(200-300).

[0027] As a further preferred scheme of the present application, the temperature of the incubator is 30-35℃;

[0028] The concentration of the Tris-HCl buffer solution is 0.2-0.5 mol / L;

[0029] The concentration of the suspension is 30-50 mg / L.

[0030] As a further preferred scheme of the present application, the use amount ratio of sodium alginate, polyvinyl alcohol, deionized water and modified activated carbon is (5-10) g:(8-13) g:(80-100) mL:(3-7) g;

[0031] The temperature of the constant temperature standing is 40-45 DEG C.

[0032] As a further preferred scheme of the present application, the proportion of the starch, carboxymethyl cellulose, deionized water and xanthan gum in the binder is (5-10) g:(5-10) g:(30-50) mL:(3-7) g.

[0033] The mass ratio of the secondary modified activated carbon, the composite activated carbon and the binder is (15-20):(5-10):(8-12).

[0034] A columnar activated carbon with high SO2 removal efficiency is prepared by the preparation method.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] In the present application, the activated carbon is modified by acid and alkali liquor, the acid and alkali liquor can etch the activated carbon to some extent, resulting in the change of the carbon skeleton structure, the internal pore of the activated carbon is opened to form micropores, so that the surface area and the micropore volume of the activated carbon are increased, providing sufficient space for the infiltration of the subsequent treatment agent and the suspension; in order to realize the qualitative adsorption of sulfur dioxide, the treatment agent formed by diethyl sulfate, ethyl acetate and tetramethyl ethylenediamine is immersed into the modified activated carbon by a simple immersion method, thereby forming the secondary modified activated carbon with a coating layer, the coating layer fills the pores on the surface of the secondary modified activated carbon, so that the surface of the secondary modified activated carbon is almost in a non-porous state, and since the treatment agent in the secondary modified activated carbon can have a good trapping effect on sulfur dioxide, the trapped sulfur dioxide enters the interior of the secondary modified activated carbon after the treatment agent and fills in the internal pores, while other kinds of gas are blocked by the treatment agent and cannot enter the interior of the secondary modified activated carbon, so that the secondary modified activated carbon can perform directional adsorption on sulfur dioxide, and since the immersion treatment of the treatment agent adopts a conventional immersion, the treatment agent cannot infiltrate into the deep part of the modified activated carbon and mainly exists on the surface of the modified activated carbon, so that the pore volume of the modified activated carbon is not greatly affected, so that the formed secondary modified activated carbon not only can perform directional adsorption on sulfur dioxide, but also has a large adsorption capacity and a good removal effect.

[0037] In order to further improve the removal effect of sulfur dioxide, in the application, polyvinyl alcohol, sodium alginate and modified activated carbon are used as a composite carrier, and the ferrous iron oxidizing bacteria are limited in the microporous structure of the composite carrier to obtain the composite activated carbon, and the ferrous iron oxidizing bacteria can remove sulfur dioxide, and the removal effect of sulfur dioxide is good, and in order to prevent the ferrous iron oxidizing bacteria from separating from the composite carrier, the polyvinyl alcohol and the sodium alginate are mixed and crosslinked in a calcium salt solution to form a network structure, so that the activity space of the ferrous iron oxidizing bacteria can be limited, and the loss of the ferrous iron oxidizing bacteria can be inhibited, and the ferrous iron oxidizing bacteria can be limited and fixed, so that the retention rate of the ferrous iron oxidizing bacteria in the composite carrier is greatly improved, and the composite activated carbon has a long service life.

[0038] In the application, the binder composed of starch, carboxymethyl cellulose and xanthan gum is used as a connecting medium, the secondary modified activated carbon and the composite activated carbon are bonded into one after drying at room temperature, the influence of high-temperature drying on the activity of the ferrous iron oxidizing bacteria is avoided, and the columnar activated carbon is obtained, the columnar activated carbon has excellent removal effect on sulfur dioxide, and sulfur dioxide can be removed with high efficiency, so that the pollution of sulfur dioxide in the atmosphere is reduced. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the application will be clearly and completely described below, obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0040] In the embodiments of the application, the treatment liquid A is composed of 8mol / L nitric acid solution, 4mol / L sulfuric acid solution and 6mol / L phosphoric acid solution with a volume ratio of 1:1.5:1.5;

[0041] The treatment liquid B is composed of 5mol / L sodium hydroxide solution and 12wt% ammonia water with a volume ratio of 1:2.5.

[0042] The culture medium is composed of the A liquid and the B liquid which are both subjected to sterilization treatment, and the volume ratio of the two is 7:3.

[0043] The A liquid is composed of ammonium sulfate, potassium chloride, magnesium sulfate, calcium nitrate and distilled water with a mass ratio of 3:0.1:1.2:0.06:700.

[0044] The B liquid is composed of ferrous sulfate and distilled water with a mass ratio of 50:300.

[0045] Embodiment 1

[0046] A method for preparing a columnar activated carbon with high SO2 removal efficiency, specifically comprising the following steps:

[0047] S1 primary modification treatment of activated carbon

[0048] 1) ultrasonic washing of activated carbon in anhydrous ethanol for 10 min, soaking for 20 min, ultrasonic washing with deionized water for 20 min, repeated rinsing, and drying in an oven at 110 DEG C until constant weight to obtain pretreated activated carbon;

[0049] 2) preparation of treatment liquid A and treatment liquid B, immersion of pretreated activated carbon in sufficient treatment liquid A and treatment liquid B respectively, constant temperature soaking in a 70 DEG C water bath for 4 h, shaking bed oscillation at 35 DEG C and 300 r / min for 20 h, repeated washing with deionized water until neutral, drying to obtain modified activated carbon;

[0050] S2 secondary modification treatment of activated carbon

[0051] 1) addition of 1.5 g diethyl sulfate to 200 mL ethyl acetate, stirring, transfer to an ice water bath, slow dropwise addition of 1.2 g tetramethyl ethylenediamine, continuous reaction for 12 h, after the reaction is completed, removal of the upper clear liquid, repeated washing of the remaining liquid with ethyl acetate, and transfer to a vacuum drying oven for drying at 80 DEG C for 10 h to obtain a treatment agent;

[0052] 2) ultrasonic dispersion of 1 g modified activated carbon in 20 mL anhydrous ethanol to obtain a suspension, addition of 1.5 g treatment agent to the suspension, stirring at 300 r / min at room temperature for 10 h, removal of anhydrous ethanol from the formed mixture by rotary evaporation, and transfer to a vacuum drying oven for drying at 80 DEG C for 10 h to obtain secondary modified activated carbon;

[0053] S3 preparation of composite activated carbon

[0054] 1) inoculation of Thiobacillus ferroxidans into culture medium at an inoculation amount of 10%, adjustment of the temperature of the incubator to 30 DEG C, shaking bed culture at 100 r / min for 5 h, collection of the culture liquid, centrifugation at 10000 r / min for 5 min, washing and resuspension in Tris-HCl buffer with a concentration of 0.2 mol / L to obtain a suspension with a concentration of 30 mg / L;

[0055] 2) addition of 5 g sodium alginate and 8 g polyvinyl alcohol to 80 mL deionized water, stirring in a 90 DEG C constant temperature water bath until completely dissolved, cooling to room temperature, addition of 3 g modified activated carbon, uniform dispersion to obtain a dispersion liquid, then mixing equal volumes of the dispersion liquid and the suspension, and slow dropwise addition to saturated calcium chloride solution, constant temperature standing at 40 DEG C for 8 h, removal of the product, repeated washing with normal saline to obtain composite activated carbon.

[0056] Preparation of S4 columnar activated carbon

[0057] 5g starch, 5g carboxymethyl cellulose and 30mL deionized water were uniformly mixed, heated to 40℃, 3g xanthan gum was added under stirring, and stirring was continued for 20min to obtain a binder. After 15g of secondary modified activated carbon, 5g of composite activated carbon and 8g of the binder were thoroughly mixed, kneading into columnar shape, and dried at room temperature, the desired columnar activated carbon was obtained.

[0058] Example 2

[0059] A method for preparing columnar activated carbon with high SO2 removal efficiency, specifically comprising the following steps:

[0060] S1 primary modification treatment of activated carbon

[0061] 1) The activated carbon was placed in anhydrous ethanol and ultrasonically washed for 15min, soaked for 25min, then ultrasonically washed with deionized water for 25min, and after repeated rinsing, placed in an oven and dried at 130℃ to constant weight to obtain pretreated activated carbon;

[0062] 2) Preparation of treatment liquid A and treatment liquid B, the pretreated activated carbon was immersed in sufficient treatment liquid A and treatment liquid B respectively, and soaked in a 75℃ water bath for 5h, and then shaken in a shaking table at 37℃ and 400r / min for 25h, then filtered and washed repeatedly with deionized water until neutral, and dried to obtain modified activated carbon;

[0063] S2 secondary modification treatment of activated carbon

[0064] 1) 2g of diethyl sulfate was added to 250mL of ethyl acetate, stirred thoroughly, then transferred to an ice water bath, and 1.5g of tetramethyl ethylenediamine was slowly added dropwise, and the reaction was continued for 14h. After the reaction was completed, the upper clear liquid was taken out, and the remaining liquid was repeatedly washed with ethyl acetate, then transferred to a vacuum drying oven and dried at 83℃ for 12h to obtain a treatment agent;

[0065] 2) 2g of modified activated carbon was ultrasonically dispersed in 40mL of anhydrous ethanol to obtain a suspension, 2.6g of the treatment agent was added to the suspension, and stirred at room temperature at 400r / min for 13h, then the mixed liquid was rotary evaporated to remove anhydrous ethanol, and transferred to a vacuum drying oven and dried at 82℃ for 13h to obtain secondary modified activated carbon;

[0066] S3 preparation of composite activated carbon

[0067] 1) inoculate Thiobacillus ferroxidans into the culture medium at a 15% inoculation amount, adjust the temperature of the incubator to 32℃, and shake culture at 130 r / min for 8h, collect the culture solution, centrifuge at 15000 r / min for 7min, wash and resuspend in Tris-HCl buffer with a concentration of 0.4mol / L, to obtain a suspension with a concentration of 40mg / L;

[0068] 2) add 7g of sodium alginate and 10g of polyvinyl alcohol into 90mL of deionized water, stir in a constant temperature water bath at 92℃ until completely dissolved, cool to room temperature, then add 5g of modified activated carbon, disperse uniformly to obtain a dispersion, then mix equal volume of the dispersion and the suspension uniformly, slowly drop into saturated calcium nitrate solution, incubate at 42℃ for 9h, take out the product and wash repeatedly with normal saline to obtain the composite activated carbon;

[0069] Preparation of S4 columnar activated carbon

[0070] Mix 7g of starch, 8g of carboxymethyl cellulose and 40mL of deionized water uniformly, heat to 42℃, add 5g of xanthan gum under stirring, continue stirring for 25min to obtain a binder, mix 18g of secondary modified activated carbon, 6g of composite activated carbon and 10g of binder thoroughly, then knead into columnar shape, dry at room temperature to obtain the desired columnar activated carbon.

[0071] Example 3

[0072] A method for preparing columnar activated carbon with high SO2 removal efficiency, specifically comprising the following steps:

[0073] S1 primary modification treatment of activated carbon

[0074] 1) ultrasonically wash the activated carbon in anhydrous ethanol for 20min, soak for 30min, then ultrasonically wash with deionized water for 30min, repeatedly rinse and place in an oven to dry at 150℃ until constant weight to obtain pretreated activated carbon;

[0075] 2) prepare treatment solution A and treatment solution B, immerse the pretreated activated carbon in sufficient treatment solution A and treatment solution B respectively, incubate in a 80℃ water bath for 6h, shake at 40℃ and 500r / min for 30h, then filter, repeatedly wash with deionized water until neutral, dry to obtain modified activated carbon;

[0076] S2 secondary modification treatment of activated carbon

[0077] 1) 2.5 g diethyl sulfate was added to 300 mL ethyl acetate, after being stirred thoroughly, it was transferred to an ice water bath, then 1.8 g tetramethyl ethylenediamine was slowly added dropwise, the reaction was continued for 16 h, after the reaction was completed, the supernatant was taken out, the remaining liquid was repeatedly washed with ethyl acetate, then it was transferred to a vacuum drying oven, dried at 85 °C for 15 h to obtain a treating agent;

[0078] 2) 3 g modified activated carbon was ultrasonically dispersed in 50 mL anhydrous ethanol to obtain a suspension, 3.0 g treating agent was added to the suspension, stirred at 500 r / min for 15 h at room temperature, then the formed mixture was rotary evaporated to remove anhydrous ethanol, transferred to a vacuum drying oven, dried at 85 °C for 15 h to obtain a second modified activated carbon;

[0079] S3 Preparation of composite activated carbon

[0080] 1) Thiobacillus ferroxidans was inoculated into the culture medium at an inoculation amount of 20%, the temperature of the incubator was adjusted to 35 °C, and the culture was incubated at 150 r / min for 10 h, the culture solution was collected, centrifuged at 20,000 r / min for 10 min, washed and resuspended in Tris-HCl buffer with a concentration of 0.5 mol / L to obtain a suspension with a concentration of 50 mg / L;

[0081] 2) 10 g sodium alginate and 13 g polyvinyl alcohol were added to 100 mL deionized water, stirred in a constant temperature water bath at 95 °C until completely dissolved, cooled to room temperature, then 7 g modified activated carbon was added, uniformly dispersed to obtain a dispersion, then an equal volume of the dispersion and the suspension were mixed uniformly, slowly dropped into a saturated calcium nitrate solution, placed at a constant temperature of 45 °C for 10 h, the product was taken out and repeatedly washed with normal saline to obtain a composite activated carbon;

[0082] S4 Preparation of columnar activated carbon

[0083] 10 g starch, 10 g carboxymethyl cellulose and 50 mL deionized water were uniformly mixed, heated to 45 °C, 7 g xanthan gum was added under stirring, and the stirring was continued for 30 min to obtain a binder, 20 g second modified activated carbon, 10 g composite activated carbon and 12 g binder were thoroughly mixed, then kneaded into a columnar shape, and the columnar activated carbon was obtained after drying at room temperature.

[0084] Comparative Example 1: The comparative example was basically the same as Example 1, except that the activated carbon was not pretreated.

[0085] Comparative Example 2: The comparative example was basically the same as Example 1, except that the pretreated activated carbon was used instead of the modified activated carbon in the second modification of the activated carbon.

[0086] Comparative Example 3: The comparative example is basically the same as Example 1, except that the preparation process of the composite activated carbon uses the pretreated activated carbon instead of the modified activated carbon.

[0087] Comparative Example 4: The comparative example is basically the same as Example 1, except that the preparation process of the columnar activated carbon does not contain the secondary modified activated carbon.

[0088] Comparative Example 5: The comparative example is basically the same as Example 1, except that the preparation process of the columnar activated carbon does not contain the composite activated carbon.

[0089] Control group: directly using the modified activated carbon.

[0090] Test experiment:

[0091] The columnar activated carbon provided by Examples 1-3, Comparative Examples 1-5 and the control group is subjected to a sulfur dioxide adsorption removal test, and the method is as follows: the columnar activated carbon provided by Examples 1-3, Comparative Examples 1-5 and the control group is placed in a closed reaction chamber, and the pollution gas in the reaction chamber is a mixed gas of sulfur dioxide and carbon dioxide, and the concentration is 1.0 mg / m 3 After the columnar activated carbon is exposed and placed for 8 hours, the indoor gas reaches equilibrium again, the concentration of sulfur dioxide in the reaction chamber is determined by gas chromatography, and the removal rate of sulfur dioxide in 8 hours is calculated; the results are shown in Table 1.

[0092] Table 1

[0093]

[0094]

[0095] As can be seen from Table 1, the columnar activated carbon in the present application has high removal efficiency for sulfur dioxide, and can quickly and efficiently remove sulfur dioxide in the atmosphere, thereby reducing pollution.

[0096] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details, nor limit the present application to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of the present application. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited only by the claims and their entire scope and equivalents.

Claims

1. A method for producing a columnar activated carbon having a high SO2 removal efficiency, characterized by comprising the steps of: Specifically comprising the following steps: ​ S1 primary modification treatment of activated carbon 1) The activated carbon is ultrasonically washed with anhydrous ethanol and deionized water respectively and then dried to obtain pretreated activated carbon; 2) The pretreated activated carbon is immersed in sufficient prepared treatment liquid A and treatment liquid B respectively, soaked in a constant-temperature water bath for 4-6 h and then shaken on a shaking table for 20-30 h, washed repeatedly with deionized water until neutral, dried to obtain modified activated carbon; S2 secondary modification treatment of activated carbon 1) Diethyl sulfate is added to ethyl acetate, stirred thoroughly, transferred to an ice water bath, and then tetramethyl ethylenediamine is slowly added dropwise, continuously reacted for 12-16 h, after the reaction is completed, the upper clear liquid is taken out, the remaining liquid is washed repeatedly with ethyl acetate, and then transferred to a vacuum drying oven for drying to obtain a treatment agent; 2) The modified activated carbon is ultrasonically dispersed in anhydrous ethanol to obtain a suspension, the treatment agent is added to the suspension, stirred at room temperature for 10-15 h, then the mixed liquid formed is rotary evaporated to remove anhydrous ethanol, and then transferred to a vacuum drying oven for drying to obtain secondary modified activated carbon; S3 preparation of composite activated carbon 1) The thiobacillus ferroxidans is inoculated into a culture medium at an inoculation amount of 10-20%, placed in a culture box and shaken on a shaking table at 100-150 r / min for 5-10 h, the culture solution is collected, washed after centrifugation, and resuspended in a Tris-HCl buffer to obtain a suspension; 2) Sodium alginate and polyvinyl alcohol are added to deionized water, stirred in a constant-temperature water bath at 90-95℃ until completely dissolved, cooled to room temperature, the modified activated carbon is added, uniformly dispersed to obtain a dispersion, then equal volumes of the dispersion and the suspension are mixed uniformly, slowly dropped into a saturated calcium salt solution, and constant-temperature standing is performed for 8-10 h, the product is taken out and washed repeatedly with normal saline to obtain composite activated carbon; S4 preparation of columnar activated carbon The starch, carboxymethyl cellulose and deionized water are uniformly mixed, heated to 40-45℃, and then xanthan gum is added under stirring, continuously stirred for 20-30 min to obtain a binder, the secondary modified activated carbon, the composite activated carbon and the binder are thoroughly mixed, and then kneaded into a columnar shape, and then dried at room temperature to obtain the required columnar activated carbon; The treatment liquid A is composed of 5-10 mol / L nitric acid solution, 3-6 mol / L sulfuric acid solution and 5-8 mol / L phosphoric acid solution with a volume ratio of 1:(1-2):(1-2); The treatment liquid B is composed of 3-7 mol / L sodium hydroxide solution and 10-15 wt% ammonia water with a volume ratio of 1:(2-3); The culture medium is composed of A liquid and B liquid which have been sterilized, and the volume ratio of the two is (7-8):(2-3), wherein the A liquid is composed of ammonium sulfate, potassium chloride, magnesium sulfate, calcium nitrate and distilled water with a mass ratio of (3-5):(0.1-0.5):(0.5-1.2):(0.01-0.06):(700-800); The B liquid is composed of ferrous sulfate and distilled water with a mass ratio of (42-50):(200-300).

2. The method for preparing columnar activated carbon with high SO2 removal efficiency according to claim 1, characterized in that, The water bath temperature is 70-80℃; The shaking bed oscillation is carried out at 35-40℃ and 300-500r / min.

3. The method for preparing columnar activated carbon with high SO2 removal efficiency according to claim 1, characterized in that, The proportion of diethyl sulfate, ethyl acetate and tetramethyl ethylenediamine is (1.5-2.5)g:(200-300)mL:(1.2-1.8)g.

4. The method for preparing columnar activated carbon with high SO2 removal efficiency according to claim 1, characterized in that, The proportion of modified activated carbon, absolute ethyl alcohol and treating agent is (1-3)g:(20-50)mL:(1.5-3.0)g. The stirring speed is 300-500r / min.

5. The method for preparing columnar activated carbon with high SO2 removal efficiency according to claim 1, characterized in that, The temperature of the incubator is 30-35℃. The concentration of Tris-HCl buffer is 0.2-0.5mol / L. The concentration of the suspension is 30-50mg / L.

6. The method for preparing columnar activated carbon with high SO2 removal efficiency according to claim 1, characterized in that, The proportion of sodium alginate, polyvinyl alcohol, deionized water and modified activated carbon is (5-10)g:(8-13)g:(80-100)mL:(3-7)g. The temperature of the constant temperature standing is 40-45℃.

7. The method for preparing columnar activated carbon with high SO2 removal efficiency according to claim 1, characterized in that, The proportion of starch, carboxymethyl cellulose, deionized water and xanthan gum in the binder is (5-10)g:(5-10)g:(30-50)mL:(3-7)g. The mass ratio of the secondary modified activated carbon, composite activated carbon and binder is (15-20):(5-10):(8-12).

8. A columnar activated carbon with high SO2 removal efficiency, characterized in that, The preparation method of any one of claims 1-7. The preparation method of any one of claims 1-7.

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